The USGS Reference Sample 

Devonian Ohio Shale SD0-1 

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The USGS Reference Sample 

Devonian Ohio Shale SD0-1 

Edited by JEAN S. KANE 

This publication presents a collection of detailed analytical 

procedures used by some of the laboratories whose data was 

used to derive recommended concentrations for SD0-1 as a 

geochemical reference sample, and outlines the statistical 

evaluation used in the derivation of those concentrations from 

the total data base. 

U.S. GEOLOGICAL SURVEY BULLETIN 2046 
U.S. DEPARTMENT OF THE INTERIOR 

BRUCE BABBITI, Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas l. Peck, Director 

Any use of trade, product, or firm names 

in this publication is for descriptive purposes only 

and does not imply endorsement by the U.S. Government 

UNITED STATES GOVERNMENT PRINTING OFFICE: 1993 

For sale by 

U.S. Geological Survey, Map Distribution 

Box 25286, Bldg. 810, Federal Center 

Denver, CO 80225 

Library of Congress Cataloging in Publication Data 

The USGS reference sample Devonian Ohio Shale SD0-1 I edited by jean S. 

Kane. 

p. em. - (U.S. Geological Survey bulletin ; 2046) 

Includes bibliographical references. 

Supt. of Docs. no.: I 19.3:2046 

1. Ohio Shale. I. Kane, jean S. II. Series. 

QE75.B9 no. 2046 

[QE471.15.S5] 

557.3 s-dc20 

[553.2'83'0973] 92-38658 

CIP 
CONTENTS 

[Letters designate the chapters] 

A. Statistical Treatment of Contributed Data in the Derivation of Recommended 

Concentrations for Devonian Ohio Shale SD0-1, by JeanS. Kane 

B. Determination of Major and 11 Trace Elements (XRF), Gold (AAS), Carbon and 

Sulfur (COUL) in USGS Devonian Ohio Shale SD0-1, by Otmar Spies, Bernhard 

Stribmy, Josef Konopasek, and Hans Urban 

C. Inductively Coupled Plasma Determination of Nine Rare Earth Elements in the 

USGS Devonian Ohio Shale SD0-1, by I wan Roelandts 

D. Instrumental Neutron Activation Analysis of Devonian Ohio Shale SD0-1, by 

Gregory A. Wandless 

E. Relation Between Volatile Components and Loss on Ignition, as Applied to the 

Analysis of USGS Reference Devonian Ohio Shale SD0-1 and Rare Earth 

Element Analyses, by Miroslav Huka and Ivan Rubeska 

F. A Study to Determine Sources of Interlaboratory Variability in Measured Loss on 

Ignition (LOI) for Devonian Ohio Shale SD0-1, by Jean S. Kane and Carol J. 

Skeen 

G. Analysis of SD0-1 Pressed Powder Pellets by X-ray Fluorescence-A Note of 

Caution, by Otto C. Kopp and Francis C. Furman 

The USGS Reference Sample Devonian Ohio Shale 

SD0-1 

Edited by Jean S. Kane 

INTRODUCTION 

The United States Geological Survey (USGS) has 

maintained a geochemical reference sample (GRS) program 

since 1951, when the Fairbairn report on the cooperative 

analysis of G-1 and W-1 was issued. Many of the reference 

samples developed and issued to the worldwide geochemical community since then have been igneous rocks whose 

elemental concentrations are quite well established, making 

the GRS's comparable to National Institute of Standards 

and Technology (NIST) certified or standard reference 

samples (SRM's). For the most part, these igneous rock 

reference samples have trace element concentrations at 

rather low levels, approaching average crustal abundances. 

These materials are quite useful in baseline geochemical 

applications, but of less value in exploration programs or in 

studies of ore genesis where higher trace elemental abundances are characteristic of the samples actually being 

analyzed. These materials are sometimes poorly suited, by 

virtue of matrix mismatches, for use in studies of metamorphic and sedimentary rocks, including gas and oil shales 

and coal. USGS has begun developing a number of new 

reference samples to meet these added needs. This bulletin 

is devoted to the development of one of these new materials, Devonian Ohio Shale SD0-1. (Note that there is a 

homonym of this material, the marine sediment SD0-1 

issued by the USSR Academy of Sciences (Arnautov, 

1987).) 

SD0-1, a gas shale, was first introduced in the 

seventies as a control sample during the Eastern Gas Shale 

Project sponsored by the U.S. Department of Energy (DOE) 

(1978), in which the USGS was a participant. The sample is 

a brownish-black, relatively radioactive shale (40-100 

counts/second, or 2-4 times background over 0-200 ft) that 

weathers blocky and massive in the lower two-thirds of the 

unit and is less resistant in the upper one-third of the unit. 

Manuscript approved for publication September 15, 1992. 

Thin-sections show the shale to be organic-rich with a 

fine-ground clay matrix and abundant microfossils and 

pyrite; the pyrite is also observed in hand specimens 

(Kepferle and others, 1985; Provo and others, 1978). The 

sample was collected from a fresh road cut along U.S. 

Highway 64, about 8 mi west of Morehead, Rowan County, 

Ky., at lat 38°09'56''N., long 83°35'38''W. (Kepferle and 

others, 1985). 

A preliminary report (Kepferle and others, 1985) 

proposed elemental concentrations based on a limited data 

base. Recommended concentrations published since then 

(Kane and others, 1990) (table 1) were derived from a larger 

data set that included the original Eastern Gas Shale Project 

data the International Geological Congress (IGC) Metalliferou~ Black Shales (#254) Project, and concurrent contributions from USGS and other laboratories. 

This report contains details of the statistical treatment 

used for derivation of recommended concentrations from 

the collected data. That treatment, published previously 

(Kane and others, 1990), is summarized in table 2. This 

report also contains conclusions as to analytical method(s) 

of choice for individual elements and presents some of the 

more accurate methods used in the collaborative analytical 

programs leading to recommended concentrations for the 

material. Some of these methods (for example, Spies and 

others (chap. B, this vol.) and Roelandts (chap. C, this 

vol.)) are routine procedures applied without any necessary 

modifications due to the unique sample matrix. Other 

methods (for example, Wandless (chap. D, this vol.) and 

Huka and Rubeska (chap. E, this vol.)) require nonroutine 

application to obtain accurate analyses of SD0-1. The shale 

is the most sulfur-rich and the most organic-rich of any 

samples in the USGS GRS suite. The high sulfur and 

organic carbon contents of the material presented unique 

analytical problems affecting the accuracy or trueness of 

analysis. The analytical methods are presented here in order 

to assist laboratories in improving their procedures for shale 

analysis. 

Introduction 
Table 1. Summary of constituent concentrations for USGS Devonian Ohio Shale SD0-1 

Si02 

Al20 3 

Fe203 ToT 

CaO 

MgO 

Na20 

K20 

P20s 

Ti02 

MnO 

Recommended: weight percent 

in sample, as received 

49.28±0.63 

12.27±0.23 

9.34±0.21 

1.05±0.047 

1.54±0.038 

.38±0.026 

3.35±0.061 

.11±0.007 

.71±0.031 

.042±0.005 

As 

Ba 

Ce 

Co 

Cr 

Dy 

Eu 

Ga 

La 

Mo 

Nb 

Nd 

Recommended: f.Lg/g 

in sample, as received 

68.5±8.6 Ni 

397±38 Pr 

79.3±7.8 Rb 

46.8±6.3 Sc 

66.4±7.6 Sm 

6.0±0.65 Sr 

1.6±0.22 u 

16.8± 1.8 v 

38.5±4.4 y 

134±21 Yb 

11.4± 1.2 Zn 

36.6±3.3 Zr 

99.5±9.9 

8.9±0.66 

126±3.9 

13.2± 1.5 

7.7±0.81 

75.1±11.0 

48.8±6.5 

160±21 

40.6±6.5 

3.4±0.46 

64.1±6.9 

165±24 

Average: weight percent 

in sample, as received 

Average: f.Lg/g Range: f.Lg/g 

LOI 

s 

C02 

CTOT 

corg (measured) 

corg (calculated) 

H20- (moisture) 

HTOT 

NTOT 

21.7±0.90 

5.35±0.44 

1.01 ±0.21 

9.95±0.44 

(range 8.98-10.4) 

9.68±0.45 

1.21 ±0.50 

1.34±0.06 

.347±0.043 

in sample, as received 

B 128±11 

Be 3.3±0.57 

Cs 6.9±1.2 

Cu 60.2±9.6 

Er 3.6±0.55 

F 697±88.5 

Gd 7.4±1.9 

Hf 4.7±0.75 

Hg .19±0.08 

Ho 1.2±0.11 

Li 28.6±5.5 

Lu .54±0.14 

Pb 27.9±5.2 

Sn 3.7±1.2 

Ta 1.1±0.13 

Tb 1.2±0.24 

Tm .45±0.08 

in sample, as received 

Ag 0.094-0.17 

Au .002--0.0035 

Bi 2-<10 

Br 5 

Cd <2-<10 

Ge 1.3 

In <0.2 

Sb 4.1-4.8 

Se 1.9-6.8 

Ti 8.3 

w 3.3 

Table 2. Statistical treatment of compiled data (Kane and others, 1990, and references therein; also chap. A, this vol.) 

1. Assess normalcy of data distribution of laboratory results (each of which are the average of several replicate analyses) and iteratively 

reject as gross outliers the individual data that lead to significant deviation from normalcy at the 95 percent confidence level. 

tests: a. Arithmetic mean and median are approximately equal; 

b. Distribution is neither skewed nor kurtopic; and 

c. Chi-square and (or) Kolmogorov-Smirnov tests indicate normalcy. 

2. Calculate mean and standard deviation for compiled data after gross outlier rejection; convert standard deviation to relative standard 

deviation (rsd). If rsd is 2 percent for major elements, between 5 and 10 percent for minors, or 15 percent for trace elements, proceed 

to step 4. 

3. Test extreme individual laboratory average data against the compiled data mean X calculated in step 2 by means of a two-sided t-test. 

Reject any data shown to differ significantly at the 95-percent confidence level from X. Repeat steps 1 and 2 until no further rejection 

is indicated. 

4. Group laboratory average data surviving the rejection procedure by analytical method. Perform a one-way analysis of variance with 

method as the classification variable; determine significance of intermethod differences at the 95-percent confidence level. 

5a. Recommend concentrations of oxide/element ( 1) if the final iterated X is based on at least five laboratory data determined by at least 

three independent methods showing no significant method differences and (2) if the rsd of X meets step 2 criteria. 

5b. Cite the final iterated X as the average concentration of the oxide/element if it is based on at least five laboratory data but in some 

other aspect does not meet the criteria in 5a for a recommended concentration. Cite only a concentration range if there are fewer than 

five laboratory data after rejection steps 1-3. 

2 The USGS Reference Sample Devonian Ohio Shale SD0-1 
REFERENCES 

Arnautov, N. V., 1987, Reference samples of chemical composition of natural substances (in Russian): Novosibersk, USSR 

Academy of Sciences, (seeK. Govindaraju, 1989). 

Department of Energy, 1978, Second Eastern Gas Shales Symposium, 1978: Morgantown Energy Technology Center Report 

METC/SP-78/6, 461 p. 

Kane, J.S., Arbogast, B.F., and Leventhal, J.S., 1990, Characterization of Devonian Ohio Shale SD0-1 as a USGS 

geochemical reference sample: Geostandards Newsletter, v. 

14, p. 169-196. 

Kepferle, R.C., de Witt, Wallace, Jr., and Flanagan, F.J., 1985, 

Ohio Shale (Devonian), SD0-1, from Rowan County, 

Kentucky: U.S. Geological Survey Open-File Report 

85-145. 

Provo, L.J., Kepferle, R.C., and Potter, P.E., 1978, Division of 

black Ohio Shale in eastern Kentucky: American Association 

of Petrology and Geology Bulletin, 62, p. 1703-1713. 

Introduction 3 

Chapter A 

Statistical Treatment of Contributed Data 

in the Derivation of Recommended 

Concentrations for Devonian Ohio Shale 

SD0-1 

By JEAN S. KANE 

U.S. GEOLOGICAL SURVEY BULLETIN 2046 

THE USGS REFERENCE SAMPLE DEVONIAN OHIO SHALE SD0-1 

CONTENTS 

Abstract Al 

Introduction Al 

Between-Bottle Variances Al 

Tests to Identify Outliers for Rejection A2 

Distribution of the Data A2 

t-Test for Comparison of Individual Laboratory Results With the Overall 

Mean A3 

Between-Method Variance A3 

Alternative Identification of Outliers Based on Quality-Control Practices AS 

Frequency of Use and Accuracy of Methods Used by Laboratories in SD0-1 

Analysis A6 

Major Oxides A6 

Trace Elements A 7 

Updates of the Original Compilation Recommended Concentrations All 

Conclusion Al2 

References Al2 

Appendix 1. Major/Minor Oxides: Laboratory Methods and Averages Al4 

Appendix 2. Trace Elements: Laboratory Methods and Averages A20 

FIGURES 

1. S-curve showing distribution of Si02 results for SD0-1 A2 

2. Graphs showing fit of data (cumulative frequency) to theoretical Chi-square 

distribution and to normal distribution A3 

3. Ce data ranges for each method of analysis A9 

4. As data ranges for each method of analysis A9 

5. Co data ranges for each method of analysis AlO 

6. Cr data ranges for each method of analysis AlO 

7. Ni data ranges for each method of analysis AlO 

8. Cu data ranges for each method of analysis AlO 

TABLES 

1. Step-by-step iteration of SD0-1 Ba recommended concentration in ~g/g A4 

2. Between-laboratory analysis of variance: Si02 AS 

3. Between-method analysis of variance: Si02 AS 

4. Summary of major oxide analyses by method A6 

5. Summary of trace element analyses by method AS 

6. Selected rare earth elements: Comparison of results from INAA, ICP-AES after 

separation, ICP-MS methods A9 

7. Between-method analysis of variance for trace elements whose concentrations are 

recommended All 

8. Examples for which newly added data do not lead to changes in recommended 

concentrations Al2 

9. Examples for which newly added data result in changes in reported concentrations 

except as noted Al2 

Statistical Treatment of Contributed Data in the 

Derivation of Recommended Concentrations for 

Devonian Ohio Shale SD0-1 

By jean S. Kane 

Abstract 

This report presents details of the statistical procedures used to derive recommended concentrations for 

the U.S. Geological Survey reference shale SD0-1 from 

data contributed by many U.S. Geological Survey and 

oth.er geochemical laboratories. These include analysis of 

vanance both to evaluate material homogeneity and to 

assess the significance of differences in constituent analyses between laboratories and (or) methods of analysis. 

Also included is a review of analytical methods used for 

individual elements, with evaluation of which one(s) are 

most accurate and precise and which are most subject to 

potential systematic error. 

INTRODUCTION 

The U.S. Geological Survey (USGS) geochemical 

reference sample (GRS) Devonian Ohio Shale SD0-1 (note 

that a Russian reference sediment sample is also called 

SD0-1) was first introduced as a control sample in conjunction with the Eastern Gas Shale program, 1976-1981. 

Publications of analytical results from that program (Leventhal and others, 1978; Department of Energy, 1978) and 

tentative recommended concentrations (Kepferle and others, 1985) have been followed by a number of reports (for 

example, Frost and others, 1985; Coveney and Glascock, 

1989; Kane and others, 1990; Leventhal and Knapp, 1988) 

that indicate the continued geochemical interest in metalliferous black shales. One of these (Kane and others, 1990) 

presented recommended concentrations and their uncertainties for 40 elements, based on contributed data from more 

than 50 laboratories worldwide. 

Analytical laboratories providing analyses for metalliferous black shale geochemical studies require an appropriately matrix-matched GRS to validate analytical methods 

and otherwise ensure analytical accuracy. A review of the 

collaborative data base for Devonian Ohio Shale SD0-1 

Manuscript approved for publication September 15, 1992. 

(Kane and others, 1990) indicates that although many 

laboratories are performing analyses with the required 

accuracy on SD0-1 (and presumably on metalliferous black 

shales, in general), some are experiencing difficulty with 

accurate analyses of one or several elements in samples of 

this type. This report examines the total data base with a 

view to identifying the method(s) of choice for a given 

element. The identification will be based on those methods 

showing the highest within-laboratory precision, the best 

between-laboratory repeatability, and lowest rejection rates 

in the process of deriving recommended concentrations, 

following the iterative procedure outlined in Kane and 

others (1990). 

BETWEEN-BOTTLE VARIANCES 

We begin the discussion with a review of the 

between-bottle analysis of variance (anova) presented in 

Kane and others (1990). Mineralogically, SD0-1 has three 

principal components (clay, pyrite, and organic matter) that 

differ considerably in density and composition. Sampling 

errors can be highly significant in the analyses of such 

mixtures. The ability to detect sampling error between 

bottles is a function of measurement precision for withinbottle subsamples (Kane, 1992). It is the latter which 

Ingamells illustrates for Cr in G-1 (Ingamells and Pitard, 

1986). In this example, the within-bottle subsampling error 

results for the trace element Cr because it occurs at a very 

high concentration in the mineral chromite but at a much 

lower concentration in the bulk sample. The anorthite-

/orthoclase mixture described in Ingamells and Pitard 

(1986) demonstrates that within-bottle subsampling errors 

can still be significant even though much less pronounced 

for mixtures of major mineral phases than for dispersed 

minerals in bulk sample. 

The basic homogeneity study for a reference sample 

looks primarily at sampling variance between bottles or 

between units-of-issue for the GRS. For SD0-1, significant 

bottle variances for several major oxides were found by and 

many collaborating laboratories (Kane and others, 1990), 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A1 
..... 

w 

(f) 

~ <{ 

0 

~ 

1-

...J 30 - 0 

::> c9 (f) 0 

w 0 

a: 0 

0 

LL 0 

0 8 

20 a: 

w 0 

~ 0 

a: ( 0 0 

~ 0 

10 0 

z 0 

<{ I a: 

0 0 

0 

20 30 40 50 

Si02, IN WEIGHT PERCENT 

Figure 1. 5-curve showing distribution of Si02 results for SD0-1. 

the between-bottle variances identified amounted to 90 

percent or more of the total laboratory variance for several 

of those laboratories. Furthermore, these between-bottle 

variances appear to account for roughly 50 percent of the 

between-laboratory variances for the total data set, which 

amounted to 1-percent relative standard deviations (rsd's) 

for Si02 , Al20 3 , and Fe20 3T and to about a 10 percent rsd 

for loss on ignition (LOI). 

The trace elements associated with a particular principal mineral component should be expected to exhibit 

bottle variances parallel to those for the major oxides 

comprising that mineral fraction. Thus, between-bottle 

subsampling error would be expected to occur for Cu and 

other chalcophile trace elements associated with the pyrite 

phase in SD0-1 as well as for iron. However, the occurrence of within-bottle sampling variance would degrade the 

ability to detect between-bottle sampling variance in the 

same way as would the use of a relatively imprecise 

analytical method (Kane, 1992). None of the chalcophile 

trace elements were found to be heterogeneously distributed 

between bottles. However, many had larger standard deviations of measurement in the compiled data set than 

expected for the concentrations at which they occurred, 

presumably because of a large within-bottle subsampling 

component of variance. Similarly, the rare earth elements 

(REE' s), expected to be distributed in the same manner as 

the clays, do not show the between-bottle variances noted 

for AI and Si. Although uranium and molybdenum, whose 

distributions should parallel the organic matter, are not 

measurably heterogeneous between bottles, LOI is heterogeneous. Therefore, sampling is thought to be a major 

factor in the uncertainty of compiled data averages for these 

elements. 

A2 The USGS Reference Sample Devonian Ohio Shale SD0-1 

TESTS TO IDENTIFY OUTLIERS FOR REJECTION 

Despite the reality of a significant sampling component in the between-laboratory/method analysis of variance 

for some elements, what follows will neglect that subsampling error. We will instead attempt to discern the other 

causes of interlaboratory and intermethod disagreements, 

and focus on those. 

Distribution of the Data 

The iterative process by which contributed data are 

accepted or rejected begins with an evaluation of the 

normalcy of the distribution of submitted data. Assuming 

that no bias affects any contributed data, but that all error is 

truly random, the contributed data should have a normal 

distribution (Deming, 1943; Youden, 1960). Several measures of normalcy of the distribution can be made, each 

having limitations related to the size of the data set. These 

measures are the agreement between the arithmetic mean 

and the median, the coefficients of skewness (yb1) and of 

kurtosis (b2), chi-square (X2

) and the Kolmogorov-Smimov 

maximum deviation (D) (Dixon and Massey, 1983; Lister, 

1982; Deming, 1943; Siegel, 1956). The data for Si02 

before any rejection is both negatively skewed and leptokurtic. The mean and median differ in the second significant 

figure, and the standard deviation of the mean indicates that 

error begins in the third significant figure. Both X2 and D 

indicate less than 1-percent probability of the distribution 

being normal. Visual inspection of a simple S-curve distribution of the data (fig. 1) readily reveals the outliers to be 

the two lowest and one highest compiled values. With their 

removal, all measures of goodness of fit indicate that the 

distribution is normal. The mean and median now differ 
30 

25 

>- u 20 

z 

w 

::> 15 

d 

w 

a: 10 LL 

5 

0 

48.39 49.17 50.14 

30 

25 

>- u 20 

z 

w 

::> 15 

d 

w 

a: 10 LL 

5 

0 

A 

48.39 

B 

49.17 

Si02, IN WEIGHT PERCENT 

Category (upper limits) 

50.14 

Figure 2. Fit of data (cumulative frequency) to (A) theoretical Chi-square distribution and (8) to normal distribution. 

only in the fourth significant figure. The fit of the data to 

theoretical X2 and normal distributions are shown in figures 

2A, 2B. 

t-Test for Comparison of Individual 

Laboratory Results With the Overall Mean 

Once the data distribution is normal, the high and 

jlow individual laboratory averages (XJ are compared 

to the iterated mean (X T) using a !-test (Dixon and Massey, 

1983; Lister, 1982). This rejection procedure can be overly 

severe when n is large, and inadequately rigorous when 

n is small. For example, at n=30 rejection occurs at 

I xi-XT I =0.5s, but at n=3 it occurs at I xi-XT I = 3s, where s is the standard deviation of X T" Particularly in 

view of the bottle inhomogeneities already noted, excessive 

rejection must be avoided to arrive at realistic uncertainty 

estimations for the recommended concentrations. 

Returning to the Si02 data set, once the data distribution was normal after eliminating the two lowest and one 

highest results, the interlaboratory mean had an rsd of 1.3 

percent, within the criteria range for a recommended 

major-oxide concentration. t-test criteria for n=27 would 

reject individual laboratory results deviating from the overall average by only 0. 56s, but this value approaches the 

bottle-to-bottle variation identified in the homogeneity 

study. Several successive iterations based on the t-test 

criteria have little to no effect on either the final mean or the 

final uncertainty of that value (49.28±0.63 percent at 

n=27, rsd 1.3; 49.27±0.49 percent at n= 19, rsd 1.0). 

t-test rejection is therefore not carried out. Instead, method 

analysis of variance is performed, as discussed in the next 

section, and the value of 49.28±0.63 percent is recommended for Si02 in SD0-1. 

The Ba data set will illustrate the case where all 

parameters, with the possible exception of X2

, showed the 

initial distribution to be normal. No data were rejected 

through data distribution tests, but six laboratory results 

were rejected based on !-tests. The procedure and results 

are shown in table 1. The initial X T for Ba is 440 ± 117 J.Lg/ g 

for n=26. Despite normalcy of the distribution, the uncertainty of the interlaboratory average (rsd 27 percent) is 

unacceptably large. !-test rejection occurred pairwise for 

the high and low extreme values, which differed by more 

than 0.56s (66 J.Lg/g) from XT. Iteration gave a new XT of 

437±93 J.Lg/g for n=24. At this point, reevaluation of the 

distribution indicated deterioration; all parameters were 

closer than initially to critical values at which the hypotheses of normal distribution would be rejected. Additionally, 

the magnitude of the rsd (22 percent) required further 

rejection. After the next two cycles of pairwise !-testing 

that led to one-sided rejection of high values, skewness was 

serious, X2 also indicated that the distribution was not 

normal, and the rsd (18 percent) was still too large to permit 

recommending the interlaboratory average Ba concentration 

of 419 J.Lg/g. Three further t-test iteration cycles, again 

rejecting only high values, led to XT=394±37 J.Lg/g for 

n = 19. Iteration was then suspended since the distribution 

was then normal under all tests, and the rsd of 9.4 percent 

met procedural criteria. 

Between-Method Variance 

Intermethod agreement, the final criterion for recommending an elemental concentration, parallels the National 

Institute of Standards and Technology (NIST) certification 

procedures (Uriano and Gravatt, 1977; Natrella, 1963; Cali 

and Reed, 1974; Michaelis, 1975), which require betweenmethod agreement for the certification of concentrations in 

standard reference materials (SRM's). These certified concentrations represent the closest possible estimation of "true 

value," an ideal that all analyses attempt to approach but 

nonetheless remains unknown (Youden, 1960; International 

Organization for Standardization (ISO), 1978, 1989). We 

accept the hypothesis that method averages are the same 

when that is true at the 95 percent confidence level, that is, 

when there is :::;5 percent probability that the method 

averages are statistically different. 

In the SD0-1 and most other compiled data bases, 

significant between-laboratory variances are the rule, 

not the exception, where data permits their evaluation. This 

variance is not entirely unexpected (Y ouden, 1960; 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A3 
Table 1. Step-by-step iteration of SD0-1 Ba recommended concentration in ~J-g/g 

[rds, relative standard deviation; NS, not significant; (S), significant at 95%, but not at 99%, confidence level; S, significant at both 95% and 99% 

confidence level] 

Test for normal distribution 

Mean and Number Kolmogorov- Chi-s~uare 

Smirnov (D) (X) 

standard using: 

deviation (rsd) Data Median Skewness Kurtosis (Probability dist. is normal) Decision/comment 

440±117 (27%) 26 406 NS NS 0.227 (0.14) 15.48 (0.000) Four of five tests show distribution 

428± 102 (24%) 25 404 NS NS 

437±94 (22%) 24 406 (S) NS 

428 ± 85 (20%) 23 404 s NS 

419±74 (18%) 22 401 s NS 

419±63 (15%) 21 399 s NS 

401±47 (12%) 20 394 NS NS 

394±37 (9.4%) 19 388 NS NS 

398±33 (8.3%) 18 394 NS NS 

394±29 (7.4%) 17 388 NS NS 

Bastenaire, 1979), as subtle bias is likely to affect even the 

most carefully developed and applied analytical method. 

Interlaboratory differences are evaluated with a standard 

anova procedure using laboratory rather than bottle as the 

classification variable. Complete evaluation requires that all 

contributing laboratories submit individual analytical 

results, and not just laboratory averages, so that withinlaboratory or within-method variance can be calculated. 

Although 11 laboratory averages for Si02 based 

on X-ray fluorescence (XRF) analysis survived the iterative rejection process, only four of those laboratories 

reported individual results in addition to the final laboratory 

average. For those four laboratories, the between-laboratory 

an ova shows highly significant differences, as seen in table 

2. Similarly, three laboratories using some variation of the 

Shapiro and Brannock ( 1962) "rapid rock" procedure 

obtained significantly different results. The same is true for 

three other laboratories using inductively coupled plasmaatomic emission spectrometry (ICP-AES) after an unspecified decomposition and for two laboratories using colorimetry (table 2). 

However, when method rather than laboratory 

becomes the classification variable and interlaboratory 

method averages are compared, no significant differences 

A4 The USGS Reference Sample Devonian Ohio Shale SD0-1 

normal; however, rsd exceeds limit, 

and t-test of extreme high and low 

values leads to their rejection. 

.205 (.247) 14.04 (.000) 

.263 (.063) 12.08 (.007) rsd still unacceptable and distribution 

deteriorating; continue t-test rejection. 

.255 (.098) 8.77 (.032) 

.228 (.202) 6.91 (.032) Rejection is one-sided (high values 

only) at this point; skewness is significant; with each new rejection, D 

and X2 show increasing probability 

that distribution is normal. 

.193 (.413) 5.05 (.080) 

.117 (.946) 2.86 (.240) Rsd remains unacceptable until skewness is removed. t-test indicates 

unacceptability of high value. 

.088 (.998) .249 (.618) At n= 19, rsd=9.4 percent and distribution is normal. Criteria to recommend concentration are met. 

t-tests indicate further rejection, but 

iterated concentrations change only 

slightly; further iteration is unwarranted. 

are found. The method averages for Si02 , based on XRF 

(n= 11), colorimetric (n=2), de arc AES (n= 1), and "rapid 

rock" (n=3) analyses, are the same, with >95-percent 

probability, as shown in table 3. The intermethod average 

of 49.28±0.63 percent Si02 is designated a recommended 

concentration because both the intermethod agreement and 

the magnitude of the interlaboratory relative standard deviation (rsd) meet USGS criteria for recommended concentrations (Kane and others, 1990). Again, we point out that 

roughly half of the final interlaboratory rsd is due to bottle 

differences. 

A similar evaluation process led to recommended 

concentrations for all rock-forming major oxides measured 

in SD0-1. For most major oxides other than Si02 , the 

iteration proceeded through several cycles, removing either 

a single point or paired high and low outliers as appropriate, 

before resulting in an acceptable, normal data distribution. 

For the Ba data set, five methods of analysis were 

also used by contributing laboratories; the anova procedure 

resulted in an 82 percent probability that results from all 

five methods were the same. Therefore, the Ba concentration was also recommended. 

Similarly, concentrations were recommended for 23 

other trace elements based on the outlined procedure. 
Table 2. Between-laboratory analysis of variance: Si02 in weight percent 

Method/ Laboratory mean 

laboratory and standard deviation 

XRF 2 48.43±0.59 

5 50.05±0.09 

6 48.57±0.52 

15 50.16±0.077 

17 49.54±0.067 

Fusion 1 50.05±0.12 

ICP-AES 4 48.68±0.22 

16 48.77±0.23 

Color 14 49.45±0.16 

15 48.73±0.17 

1 variance between laboratories 

F-ratio----------

variance within laboratories 

Table 3. Between-method analysis of variance anova: Si02 

Method Number of 

mean and laboratories 

standard using 

Method deviation method Anova data 

XRF 49.12±0.47 11 Degrees of 

freedom= 3, 13 

Fusion ICP-AES 49.29±0.71 3 

Color 48.97±0.39 2 F-ratio=0.115 

de arc AES 49.22 1 Probability 

method means do 

not differ=0.97 

Average values, which did not meet criteria for recommended values, were derived for LOI, moisture, C02 , Corg• 

CTOT• and 16 trace elements. 

Alternative Identification of Outliers Based on 

Quality-Control Practices 

Rejection of data could be more appropriately based 

on quality- control (QC) evidence rather than statistical tests 

by referencing a method standard operating procedure 

(SOP). For example, if the SOP reported that the routinely 

achievable accuracy of the method did not meet the criteria 

for recommended concentrations, data obtained using the 

procedure would be rejected. QC evidence could also be 

provided by reporting accurate data for an appropriate, 

previously characterized reference sample. Since neither 

option was available in characterizing SD0-1, statistical 

procedures alone were relied on in determining which data 

to reject or accept in the final data set. 

Ba data provides an excellent illustration of the 

desirability of QC criteria for rejection. In another paper in 

this volume (chap. D), Wandless discusses the large interference that U can cause in the Ba result in instrumental 

neutron activation analysis (INAA). In fact, several of the 

rejected high values in the data set were INAA values; the 

Degrees of 

freedom 

4,21 

2,11 

1,10 

F-ratio1 

29.72 

93.53 

51.04 

Probability laboratory 

means do not differ 

0.0000 

.0000 

.0001 

correction indicated in the Wandless paper would bring all 

rejected values within the uncertainty of the recommended 

concentration. SOP's from each of the contributing laboratories would be required, however, to identify whether or 

not this factor actually explained the high INAA results that 

were rejected. Acid decomposition prior to ICP-AES might 

be expected to result in low Ba results, or at least to more 

within-method variation than in a fusion data set, because of 

sulfur oxidation to sulfate and potential precipitation of Ba 

during the decomposition. The QC approach allows the 

underlying causes of poor data to be identified and, thus, 

permits correction of procedures to eliminate the error. 

Statistical procedures alone do not accomplish this aim. 

It is not always obvious how best to identify methods. 

The original rapid-rock procedure (Shapiro and Brannock, 

1962) used several single-element colorimetric or flame 

atomic absorption determinations after a fusion decomposition of the sample; today, ICP-AES substitutes for most of 

those other final measurements. Is a single, broad method 

specification of rapid rock sufficient for all of these variations? ICP-AES preceded by acid decomposition is in some 

ways distinctly different from ICP-AES preceded by fusion 

decomposition, but in other ways the two are identical. 

ICP-AES and de arc AES are distinctly different in that one 

analyzes sample after decomposition and the other analyzes 

sample without prior decomposition. The two methods have 

different excitation mechanisms, and excitation occurs at 

different temperatures, but in the final analysis both are 

based on the single atomic emission principle. We have 

used rather broad classifications rather than extremely 

narrow ones, while maintaining a distinction between solid 

sample and solution analysis. 

Ideally, at least three methods of analysis have been 

used to analyze both solid and decomposed sample, and the 

methods differ in broad classification: X-ray spectrometry, 

atomic (absorption/ emission) spectrometry, instrumental 

neutron activation analysis, mass spectrometry, classical 

wet chemistry, and others. With few exceptions, most 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 AS 
Table 4. Summary of major oxide analyses by method 

[( ), reported, but rejected; leaders (-), none reported] 

Total Number of accepted analyses that were determined by: 

number 

of data Fusion Unknown decomp de arc 

accepted Oxide WDXR ICP-AES ICP-AES INAA AAS AES Color 

26 Si02 11 3 2 1 1 

23 Al20 3 11 2 6 ( ) 4 ( ) 1 

26 Fe203TOT * 10 3 5 2 4 2 ( ) 

24 MgO 8 3 4 ( ) 4 1 

27 CaO 10 3 4 () 3 1 

24 Na20 7 3 4 3 3 2 

22 K20 10 3 3 2 3 ( ) 

25 Ti02 10 3 3 ( ) ( ) 1 

20 P20s 8 2 5 ( ) () ( ) 1 

22 MnO 7 3 6 ( ) 4 2 ( ) 

Number of rejected analyses that were determined by: 

Fusion Unknown decomp de arc 

WDXR ICP-AES ICP-AES INAA AAS AES Color 

Si02 0 0 0 1 

Al20 3 2 1 1 2 1 1 

Fe203TOT * 0 0 0 3 1 0 

MgO 1 0 2 1 0 0 

CaO 0 0 2 1 0 1 

Na20 3 0 1 0 1 0 

K20 0 0 2 1 0 2 

Ti02 0 0 0 2 0 

P20s 1 1 1 0 

MnO 1 0 0 0 0 

100 x total number rejected for method 

total number accepted for method 9% 7% 24% 140% 12% 78% 75% 

*Total iron reported as Fe20 3; occurs as FeS2 , FeC03 or FeO (Leventhal and Hosterman, 1982) 

notably LOI and H20 (tot), this goal is readily achievable 

for major oxides but much more difficult to achieve for 

trace constituents, as will be seen shortly. 

FREQUENCY OF USE AND ACCURACY OF 

METHODS USED BY LABORATORIES IN 

SD0-1 ANALYSIS 

Based on the method averages from which recommended concentrations were derived, we can draw conclusions as to (1) frequency of use, or popularity, of specific 

methods and (2) general acceptability of each of those 

methods in terms of accuracy and precision (or in ISO 

(1978) terminology, trueness and repeatability) for each 

constituent measured. Based on the percentage of laboratory averages obtained by any acceptable method that had to 

be rejected during the iteration leading to the recommended 

concentration, some conclusion regarding ease of application or trouble-free nature of the method can also be drawn. 

We now examine the compiled data with respect to these 

A6 The USGS Reference Sample Devonian Ohio Shale SD0-1 

conclusions. In doing so we must note that a sizeable 

number of laboratories did not specify the method of 

analysis used. 

Major Oxides 

Approximately 70 percent of the laboratories reporting data specified the analytical method used; from that 

specification, it was determined that X-ray fluorescence and 

atomic spectrometry provided the bulk of the major constituent data, as shown in table 4. Most laboratories using XRF 

for these analyses used the wavelength-dispersive method 

(WDXRF) and fused the samples into glass beads or discs 

prior to X-ray excitation, as described, for example, by 

Spies and others (chap. B, this vol.). Energy-dispersive 

X-ray analysis of pressed powder (EDXRF) was used by 

only one laboratory (Kopp and Furman, chap. G, this vol.). 

The standard protocol developed for clays and soils in 

Kopp's laboratory was inadequate in correcting for the shale 

matrix effects encountered in analyzing SD0-1 (Kopp and 

Furman, chap. G, this vol.). Since less than 10 percent of 
all WDXRF data in the compilation was rejected during the 

iterative process leading to recommended concentrations, it 

can be concluded that the WDXRF method is highly 

repeatable between laboratories and readily applied with 

accuracy to samples of the shale matrix. The method is 

particularly advantageous because it permits determination 

of sulfur along with other major constituents. During 

ignition prior to fusion, most sulfur is lost, but some is 

retained in ignited sample (Kane and Skeen, chap. F, this 

vol.). Measurement of both retained sulfur in ash and LOI 

is important if oxide summations are used to assess acceptability of the analysis. However, the nature of the shale 

sample introduces considerably more error in the oxide 

summation evaluation than that which occurs for typical 

igneous rocks (Lechler and Desilets, 1987), as discussed 

elsewhere in this volume (Kane and Skeen, chap. F, this 

vol.; Huka and Rubeska, chap. E, this vol.). Also, it must 

be recognized that the reporting of total iron as ferric oxide, 

following normal rock analysis convention, accurately 

reflects the iron occurrence in the ignited and fused XRF 

analytical sample, but not in the shale itself (Leventhal and 

Hosterman, 1982). This reporting convention also affects 

the oxide summation of the recommended concentrations 

for the reference sample itself, although not for the ignited 

residue that is analyzed by XRF. 

Atomic spectrometry can be subdivided into emission 

(AES) and absorption (AAS) spectrometries, and each of 

these can be subdivided as well. For example, subdivision 

of AES by excitation process would result in inductively 

coupled plasma (ICP-AES), direct current plasma (DCPAES), and de arc AES methods. In this work, each was 

treated as a different method for the method an ova statistics. 

Also, both AES and AAS could be subdivided depending 

on whether or not prior sample decomposition was required 

for analysis, leading to solid/flux, acid decomposition, 

fusion decomposition categories for the method anova. 

Although this subdivision led to several distinct atomic 

spectrometric methods for method anova, intermethod 

agreement was not considered sufficient for purposes of 

recommending concentrations if all methods were fundamentally atomic spectrometric methods. A totally independent method, for example, XRF, INAA, or gravimetry, in 

agreement with the atomic spectrometric methods, was 

required. Based on low rejection rates indicating overall 

accuracy of submitted data, fusion ICP-AES is a method of 

choice for major constituents; within-laboratory precision 

for some oxides is slightly poorer than for WDXRF, and S 

cannot be included in the analysis; but otherwise the two 

methods are equally suited to accurate and precise characterization of reference samples for their major constituents. 

Acid (or unspecified) decomposition ICP-AES and 

acid decomposition AAS were also applied successfully to 

SD0-1 analysis, as was flame photometry for Na and K. 

The obvious disadvantage of any analysis following acid 

decomposition is the inability to provide Si02 results. For 

some major constituents, chemical methods including colorimetry, volumetric analysis, and gravimetry were used by 

a small number of contributors, as were INAA analyses. 

Combustion/coulometry was the primary method for carbon 

and sulfur analyses. Chemical analyses and INAA, neither 

of which show the robustness between laboratories of 

WDXRF and atomic spectrometry, were used less frequently and had higher rejection rates and larger betweenlaboratory rsds for data surviving the rejection process than 

the optimum methods. 

Trace Elements 

Intermethod comparisons of trace element determinations are more difficult to generalize than those for major 

oxides. A wider range of methods are used, but the extent 

of overlapping coverage of specific elemental suites 

between methods is much more limited, as indicated in 

table 5. For example, INAA is used to provide a sizeable 

portion of the REE data; XRF analyses are also used 

extensively to provide Ce and La analyses, but no other 

REE data. However, direct ICP-AES without prior group 

separations and AAS are seldom used to provide any REE 

data. On the other hand, those atomic spectroscopic methods provide a major portion of data for such elements as Cu, 

Li, and Pb where INAA data are totally absent. Confirmation of values by several independent techniques was 

readily achieved for the major oxides but much harder to 

accomplish for the traces. Also, the data sets for each trace 

element were generally smaller (average n=9) than those 

for the majors (average n=20) except in a relatively few 

instances. We have already examined the intermethod Ba 

data in detail, while discussing the rejection process and 

recommended value derivation. We now will look at a 

number of other trace elements in similar detail. 

Although INAA methods historically dominated in 

the determination of REE, IDMS has long been considered 

the method of choice for the odd atomic weight REE. 

However, even in data bases for reference samples like 

BCR-1 and BHV0-1 used throughout the U.S. space 

program, the number of IDMS data points available have 

represented only a small fraction (18 percent for BCR-1 and 

5 percent for BHV0-1) of the total data set (Flanagan, 

1976; Gladney and others, 1983). More recently, both 

ICP-AES following group separation and ICP-MS methods 

have been developed for the REE, making intermethod 

validation of REE recommended concentrations possible. 

Table 6 shows that no clear superiority of one method over 

the others results from F-tests comparing method variances 

or t-tests comparing the several method averages to one 

another for most of the REE. Larger data sets, however, 

would improve the rigor of the tests and might show subtle 

differences between methods results that are not statistically 

significant in the current data set. A case in point is Ce, for 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A7 
Table 5. Summary of trace element analyses by method 

[leaders (-), none reported by that method; sepn., separation] 

Number of accepted (rejected) analyses that were determined by: 

Elements whose ICP-AES MS Other 

concentrations 

were Sepn. Hydride De arc 

recommended XRF INM Direct prior Flame or CV HGA AES ICP-MS DCP Color DNA 

As 1(1) 3(0) 3(1) 0(1) 3(1) 

Ba 8(1) 1(3) 6(2) 1(0) 3(4) 

Ce 7(0) 5(1) 3(3) 5(1) 3(0) 1(0) 

Co 3(0) 5(1) 7(0) 3(1) 

Cr 6(2) 6(0) 8(0) 5(1) 1(0) 

Dy 2(0) 6(2) 1(0) 

Eu 6(1) 1(2) 7(1) 1(0) 

Ga 2(0) 3(8) 0(1) 5(0) 

La 5(2) 7(0) 7(0) 5(0) 5(1) 1(0) 

Mo 3(1) 3(0) 7(1) 4(1) 

Nb 6(3) 4(2) 1(1) 

Nd 1(0) 7(0) 3(0) 7(0) 1(0) 1(0) 

Ni 8(1) 2(0) 6(1) 4(2) 1(0) 6(0) 1(0) 

Pr 1(0) 0(1) 6(0) 1(0) 

Rb 7(1) 3(2) 1(0) 0(1) 

Sc 1(0) 4(1) 7(0) 1(0) 4(0) 1(0) 

Sm 6(1) 1(1) 7(0) 1(0) 

Sr 9(0) 0(1) 7(0) 3(5) 

u 1(1) 8(1) 2(1) 1(0) 

v 4(0) 1(0) 9(0) 5(1) 1(0) 1(0) 

y 9(1) 5(4) 2(2) 3(3) 

Yb 6(0) 4(0) 6(1) 0(3) 1(0) 

Zn 7(0) 2(1) 6(0) 5(0) 3(2) 1(0) 

Zr 9(0) 0(2) 3(1) 5(1) 

Elements whose concentrations were reported as average 

B 0(1) 5(1) 1(0) 

Be 5(1) 1(0) 3(2) 0(1) 

Cs 1(0) 6(1) 0(1) 

Cu 6(1) 8(0) 6(0) 5(1) 1(0) 

Er 0(1) 7(0) 1(0) 

Gd 2(0) 0(1) 6(2) 1(0) 

Hf 1(0) 7(0) 

Ho 0(2) 6(0) 1(0) 

Li 5(0) 1(0) 0(2) 

Lu 7(0) 0(1) 8(0) 1(0) 

Pb 2(0) 4(0) 5(0) 5(2) 1(0) 

Sn 2(2) 0(2) 2(2) 

Ta 0(2) 6(0) 0(2) 

Tb 7(0) 0(1) 6(0) 1(0) 

Th 5(1) 

Tm 2(0) 5(0) 1(0) 1(0) 

which the individual method ranges are plotted in figure 3. probabilities increase to 55 percent and 88 percent, looking 

Apparently, solution methods (ICP-AES, with and without for agreement between either the solution (ICP-AES, 

separation, and ICP-MS) produce results that are slightly ICP-MS) or the solid-sample methods (de arc AES, XRF, 

lower than solid-sample methods (INAA, XRF, de arc INAA). 

AES). Ce is known to occur in minerals resistant to acid In deriving the recommended concentration for As, 

attack, which was used almost exclusively in obtaining the the last iteration acceptance range was 52-84 j.Lg/g. Intersolution-method results. Results from all six methods are method agreement exists with a probability of only 3 

the same, having a 33-percent probability; however, the percent between XRF, ICP-AES, INAA, and hydride 

A8 The USGS Reference Sample Devonian Ohio Shale SD0-1 
Table 6. Selected rare earth elements: Comparison of results in JJ.g/g from INAA, 

ICP-AES after separation, ICP-MS methods 

[S, significant at 95% confidence; NS, not significance at 95% confidence] 

lon exch. Sepn. 

Element INAA ICP-AES 

Ce 78.1±6.1 74.0±2.8 

Nd 36.6±3.2 37.4± 1.6 

Srn 7.8±0.40 7 .8±0.81 

Eu 1.74±0.18 1.65±0.23 

Gd 7.82±0.78 6.55±0.49 

Tb 1.07±0.19 1.28±0.19 

Lu .63±0.16 .45±0.02 

*Omits ICP-MS 

ICP 

INAA 

L OES 

60 70 80 90 

Ce (J.tglg) -METHOD RANGES 

Figure 3. Ce data ranges for each method of 

analysis. 

generation-AAS method means, but within each method 

group between-laboratory relative standard deviations of 

approximately 10 percent are found. If, we plot the full 

range of As data before rejection by method (fig. 4), we 

would intuitively reject the XRF method as providing data 

which differs from that for the other three methods. Repeating the between-method anova after removing the one XRF 

result previously retained reveals that the probability that 

the three method averages from ICP-AES, INAA, and 

hydride-AAS are the same improves considerably, to 43 

percent. Although two methods require sample dissolution, 

one does not, which suggests no decomposition error. Two 

totally different classes of method, atomic spectrometry and 

nuclear, are in agreement. The intermethod average can 

therefore be recommended, having fair confidence that no 

method-specific error source is affecting its reliability. 

On the other hand, few of the individual laboratory 

results for As agree with one another if the anova is 

performed between laboratories rather than between methods, as discussed earlier. A considerable part of the discrepancy is probably attributable to calibration protocol 

Anova* for t-Test for 

differences differences 

ICP- MS in precision in means 

73.2±1 NS NS 

7.0 NS NS 

6.8 NS NS 

1.71 NS NS 

6.9 NS NS 

.80 NS NS 

.42 NS NS 

XRF 

50 60 70 80 

As (J.tglg) - METHOD RANGES 

Figure 4. As data ranges for each method 

of analysis. 

differences. INAA and XRF in particular are often calibrated with secondary standards, and uncertainties in the 

calibration standard values can be a significant factor in the 

overall analytical error for each laboratory. A notable 

absence of hydride generation data for the sample suggests 

difficulties with that method in analyzing organic-rich (and 

(or) sulfur-rich) samples. One late addition to the data set, 

in fact, was a hydride generation As result of 38 JJ.g/g, the 

lowest result submitted. There is some indication that the 

observed bias may be due to the presence of As in an 

organo-metallic complex that does not decompose under the 

conditions used to prepare samples for hydride generation 

(A. Horowitz, personal commun., 1990). 

Because the concentration of Se in uraniferous shales 

is sometimes enriched considerably over that in most 

geochemical samples (Schultz and others, 1980) and additional Se reference samples are environmentally desirable, 

it is unfortunate that so few (3) laboratories contributed Se 

data for SD0-1. The range of those results, however, 

implies that SD0-1 contains less Se than many shales, 

approximately 5 JJ.g/g in comparison to as much as 300 JJ.g/g 

in the most enriched of the Cretaceous Pierre Shale samples 

(Schultz and others, 1980). All available Se data for SD0-1 

was obtained by INAA; hydride analysis for Se could be 

subject to interferences similar to those that affected As 

analysis by that method. 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A9 
30 40 50 60 70 

Co (JLQIQ)- METHOD RANGES 

Figure 5. Co data ranges for each method of analysis. 

B was reported by relatively few laboratories, and 

only AES methods using DCP and de arc excitation were 

used; thus, adequate confirmation of the interlaboratory 

averages by an independent technique was impossible. 

Therefore, despite the precision (rsd of 9 percent) of the 

intermethod result and an adequate number of laboratories 

(n=6) reporting B, the B value was not recommended. 

Be was similarly determined only by atomic spectrometric techniques; for this element, results obtained by 

AAS, ICP-AES, and de arc AES agreed. Confirmation by 

independent techniques is marginal; all methods are in the 

same general category, atomic spectrometry. The Be concentration is given as an average but not recommended, 

based on both an intermethod rsd of 17 percent and the lack 

of adequate independence of methods. 

Co and Cr were determined by XRF, INAA, 

ICP-AES, and de arc AES with very similar results 

regardless of method (figs. 5, 6). The same is true of Ni 

determined by XRF, ICP-AES, AAS, and de arc AES (fig. 

7). However, Cu determined by the same methods (fig. 8) 

shows a distinct difference between the XRF result and the 

three atomic spectroscopic results. In SD0-1, Cu could be 

associated with the pyritic fraction of the sample and 

therefore subject to sampling error within bottle as well as 

between bottle. This relation would make significant 

between-bottle variance, which could result in betweenlaboratory and between-method variance, very difficult to 

identify (Kane, 1992). We observe that the de arc results are 

highest, whereas those for XRF, which uses the largest 

sample weight, are lowest. If sampling were the dominant 

source of discrepancy between methods, we would expect 

the reverse, based on sample-size considerations. The 

largest sample size should provide the highest result, and 

also the most accurate (Ingamells and Pitard, 1986); therefore, other factors must account for the intermethod discrepancy in Cu results. Possibly the XRF Cu result is biased 

due to a matrix effect such as that found by Kopp and 

Furman (chap. G, this vol.) for several major oxides. 

Table 7 summarizes all of the trace element intermethod comparisons derived from the SD0-1 data base. 

A 1 0 The USGS Reference Sample Devonian Ohio Shale SD0-1 

80 

OES 

INAA 

ICP 

XRF 

50 60 70 80 

Cr(~-tglg)- METHOD RANGES 

Figure 6. Cr data ranges for each method of 

analysis. 

OES I 

ICP I 

XRF l 

AAS I 

90 100 110 

Ni (JLQig) -METHOD RANGES 

Figure 7. Ni data ranges for each method of analysis. 

XRF 

OocP ~~ -------AA-s------~~ 

ICP I 

OES 

40 50 60 70 

Cu (~-tglg) -METHOD RANGES 

Figure 8. Cu data ranges for each method of analysis. 

120 

80 

The reader is referred to the table for conclusions on 

intermethod agreement for elements not already discussed. 

We have already noted that the new methods being 

used for REE analyses, ICP-AES after separation and 

ICP-MS, are as accurate as the traditional INAA data for 

these elements. IN AA is used by compilers of referencesample data as the method of choice for a number of other 

analyses as well. The data in table 7, and the method-range 

data plotted in figures 3-8, do not support the superiority of 

INAA for many of those elements. For example, Co and Cr 

results (figs. 6, 7), discussed above, provide specific 

illustrations that XRF and ICP-AES both compare very 

favorably with INAA methods with respect to overall 

method accuracy and between-laboratory robustness. It is 
Table 7. Between-method analysis of variance for trace elements whose concentrations are recommended 

Method means in f.Lg/g 

Probability 

Element XRF ICP NAA 

As 67.5±7.1 67.8±7.1 

Ba 400±47.6 398±35.5 380 

Be 3.06±45 

Ce 80.6±9.7 74.1±3.2 78.3±9.1 

Co 43.6±6.4 46.6±4.1 46.8±5.5 

Cr 68.2±5.9 65.8±4.6 68.4±8.1 

Dy 6.1 ± 1.1 

Eu 1.7 1.7±0.03 

Ga 15.8± 1.1 17.3 

La 35±5.5 37.6±2.4 38.3±4.5 

Li 32.0±2.5 

Mo 130.7 135.6±9.6 143.2±24.6 

Nb 13.8±3.5 10.3±5.7 

Nd 36.2 34.5±3.4 38.1±5.3 

Ni 98.1±9.4 106.4±8.2 91.8 

Pb 30.1±1.9 

Sc 12.9±1.5 12.2± 1.3 

Sm 8.2±1.7 8.8±2.3 

Sr 73.5±2.6 77.8±4.9 

Th 13.3±7.3 9.95±1.0 

u 55.0±2.2 42.8±2.2 46.0±5.96 

v 179.3±27.1 160.8± 12 167 

y 41 ±6.6 38.5±6.7 39.7 

Yb 3.11±0.24 3.61±0.36 

Zn 63.5±6.2 63.8±7.6 63.4±3.4 

Zr 166.7± 13.1 156.2±13.6 

Number of elements 

determined by method 13 18 12 

more difficult to comment on comparability of withinlaboratory precision for these methods. In general, where 

concentrations are high enough and counting times long 

enough, INAA can be more precise than the other methods, 

but these conditions are not always possible. Withinlaboratory precision, however, is only one of several figures 

of merit in determining the general preferability of one 

analytical method over all others. 

UPDATES OF THE ORIGINAL COMPILATION 

RECOMMENDED CONCENTRATIONS 

Since the time SD0-1 recommended concentrations 

were first derived (March 1989) for inclusion in the July 

1989 Special Issue of Geostandards Newsletter (Govindaraju, 1989), a number of new data contributions have 

been received and incorporated in the data base. Most of 

these appeared 1 year later in the full compilation (Kane and 

others, 1990); additions since then represent less than 1 

percent of the total data base. The 1990 recommended 

concentrations for several rare earth elements differ from 

DNA(U) method 

OES Sepn. or means 

AAS de arc ICP ICP-MS the same 

76.9±4.2 0.36 

399 370± 15 .825 

4.0 3.57±.62 .234 

83.9±3.7 .64 

49.3±10.9 45.2±7.5 .85 

60.5±11.2 .33 

6.1 ±0.49 5.8 .94 

1.7 1.5 

15.5±2.5 .62 

39.4±4.2 35.9 .62 

28.8±5.4 32.4± 15.3 .78 

121.8±20.8 .47 

9.5 .30 

37 .0± 1.6 37.0 .78 

98.9±13.9 95.1±5.8 .23 

28.8±7.3 29.±5.7 .95 

13.9± 1.1 .29 

7.93±0.48 6.80 .62 

73.9±23.1 .76 

.24 

55.6 .11 

156.5 140.5±20.3 .13 

38.9±6.8 37.5 .88 

3.15±0.31 3.40 .05 

62.8±6.6 64.3±11.1 .99 

173.8±48.3 .70 

9 15 3 2 

the 1989 concentrations (Govindaraju, 1989). Fluorine data 

received just prior to publication of this volume allowed the 

fluorine reported in table 1 of the Introduction to be 

upgraded from range to average. However, revision of most 

other initial recommended concentrations cannot be justified. It is important that reference-sample recommended 

concentrations be stable over time for them to be used for 

instrumental-calibration and method-validation purposes. 

Some change in a compilation iterated mean must occur any 

time new data is added to the data base. However, because 

the changes will have no statistical significance if the newly 

contributed data value lies within the uncertainty range of 

the initial recommended concentration, "updating" the recommended concentration based on that change is unwarranted. Several iterations of the compilation average for 

Si02 , Al20 3 , and several other constituents at different 

points during the characterization program illustrate 

changes that did not justify updating the original recommended concentration (table 8). Changes that did lead to 

updating of concentrations as initially reported for REE are 

shown in table 9. In these instances, intermethod agreement 

could be established for the updated data but not for the 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A 11 
Table 8. Samples for which newly added data do not lead 

to changes in recommended concentrations 

Recommended 

based on data 

Element/ submitted before New average New average 

oxide 3/89 1/89 2/91 

Major in weight percent 

Si02 49.3±0.63 (26) 49.3±0.61 (27) 49.3±0.61 (29) 

Al20 3 12.3±0.23 (22) 2.3±0.40 (27) 2.3±0.23 (28) 

Fe20 3 9.34±0.21 (24) .36±0.27 (30) 9.38±0.21 (34) 

Trace in ~gig 

As 68.5±8.6 (7) 68.2±8.0 (8) 67.6±9.4 (11) 

Ba 397±38 (17) 394±37 (19) 394±36 (20) 

Ce 79.3±7.8 (18) 78.2±7.1 (23) 78.3±7 .03 (24) 

La 38.5±4.4 (18) 37 .6±3.0 (29) 37 .8±3.1 (30) 

Mo 134±21 (15) 136± 12 (17) 138± 18 (19) 

Zn 64.1 ±6.9 (23) 64.5±7 .0 (25) 64.6±7 .0 (26) 

original (for example, Dy); or the required number of 

individual laboratory contributions increased enough to 

meet previously unmet criteria for recommending the concentration, that is, that a minimum of five laboratory results 

remain after all rejection cycles (for example, Eu). 

CONCLUSION 

This study indicates how much information is available in compilation data bases beyond the obvious recommended or average concentrations of individual constituents. Little of that information, however, is typically 

extracted or applied either to the derivation of recommended concentrations or to uses of the reference samples 

in calibration, quality control, or other applications. The 

statistical calculations themselves, having become almost 

totally automated with the availability of modem computers, are an essential starting point. However, improvement 

of reference-sample recommended concentrations and 

thoughtful use of those concentrations in all applications 

would benefit from a detailed examination of the wealth of 

information that these data bases provide. Perhaps this 

discussion will be a first step in that direction. 

REFERENCES 

Arnautov, N.V., 1987, Reference samples of chemical composition of natural substances (in Russian): Novosibersk, USSR 

Academy of Sciences, (see K. Govindaraju, 1989). 

Bastenaire, F., 1979, Role of statistics in the certification of 

standard reference materials: Geostandards Newsletter, v. 3, 

p. 115-120. 

Cali, J.P., and Reed, W.P., 1974, The role of the National Bureau 

of Standards standard reference materials in accurate trace 

analysis in LaFleur, P.D., ed., NBS Special Publication 422, 

v. 1 ' p. 41-63 . 

Coveney, R.M., Jr., and Glascock, M.D., 1989, A review of the 

origins of metal-rich Pennsylvanian black shales, central 

USA with a inferred role for basinal brines: Applied Geochemistry, v. 4, p. 347-367. 

Deming, W.E., 1943, Statistical adjustment of data: New York, 

Dover, 18 p. 

Department of Energy, 1978, Second Eastern Gas Shales Symposium, 1978, Morgantown Energy Technology Center Report 

METC/SP-78/6, 461 p. 

Dixon, W.J., and Massey, F.J., Jr., 1983, Introduction to 

statistical analysis (4th ed.): New York, McGraw-Hill, p. 

116-119, 123-124. 

Flanagan, F.J., 1976, Descriptions and analyses of eight new 

USGS rock standards: U.S. Geological Survey Professional 

Paper 840, 192 pp. 

Frost, J.K., Zierath, D.L., and Shimp, N.F., 1985, Chemical 

composition and geochemistry of the new Albany Shale 

Group (Devonian-Mississippian) in Illinois: Illinois State 

Geological Survey Contract/Grant Report 1985-4, 134 pp. 

Gladney, E.S., Burns, C.E., and Roelandts, Iwan, 1983, 1982 

compilation of elemental concentrations in eleven United 

States Geological Survey rock standards: Geostandards 

Newsletter, v. 7, p. 3-226. 

Gladney, E.S., and Roelandts, Iwan, 1988, 1987 compilation of 

elemental concentration data for USGS BHV0-1, MAG-1, 

QL0-1, RGM-1, SCo-1, SDC-1, SGR-1, and STM-1: Geestandards Newsletter, v. 12, p. 253-362. 

Govindaraju, Kuppisami, 1989, 1989 compilation of working 

values and sample description for 272 geostandards: Geostandards Newsletter, v. 13, Special Issue, 113 pp. 

Ingamells, C.O., and Pitard, F.F., 1986, Applied geochemical 

analysis: New York, Wiley, p. 1-50. 

Table 9. Examples for which newly added data result in changes in reported concentrations in ~g/g 

except as noted 

Original 

Element Govindaraju, 1989 

Dy 5.7±0.99 Avg 

Er 2.5-4.7 Range 

Eu 1.6±0.22 Avg 

Gd 6.5± 1.2 Avg 

Ho 1.1 ±3.3 Range 

Pr 6-13.8 Range 

Tm 0.34--0.56 Range 

F (%) <0.010-<0.072 Range 

A 12 The USGS Reference Sample Devonian Ohio Shale SD0-1 

Update 

Kane and others, 1990 

6.0±0.65 

3.6±0.55 

1.6±0.22 

7.4±1.9 

1.2±0.11 

8.9±0.66 

0.45±0.08 

<0.010--0.072 

Rec 

Avg 

Rec 

Avg 

Avg 

Rec 

Avg 

Range 

This volume 

0.0697±0.0089 AVG 
International Organization for Standardization (ISO), 1978, Guide 

30-Terms and definitions used in connection with reference 

materials, 5 pp. 

---1989, Guide 35-Certification of reference materialsgeneral and statistical principles, 32 pp. 

Kane, J.S., 1992, Reference samples for use in analytical geochemistry, their availability, preparation, and appropriate 

use. Journal of Geochemical Exploration, v. 44, p. 37-63. 

Kane, J.S., Arbogast, B.F., and Leventhal, J.S., 1990, Characterization of Devonian Ohio Shale SD0-1 as a USGS 

geochemical reference sample: Geostandards Newsletter, v. 

14, p. 169-196. 

Kepferle, R.C., de Witt, Wallace, Jr., Flanagan, F.J., 1985, Ohio 

shale (Devonian), SD0-1, from Rowan County, Kentucky: 

U.S. Geological Survey Open-File Report 85-145, 14 p. 

Lechler, P.J., and Desilets, M.O., 1987, A review of the use of 

loss on ignition as a measure of total volatiles in whole rock 

analysis: Chemical Geology, v. 63, p. 341-344. 

Leventhal, J.S., Crock, J.G., Mountjoy, Wayne, Thomas, J.A., 

Shale, V.E., Briggs, P.H., Wahlberg, J.S., and Malcolm, 

M.J., 1978, Preliminary analytical results for a new U.S. 

Geological Survey Devonian Ohio Shale standard SD0-1: 

U.S. Geological Survey Open-File Report 78-447, 11 p. 

Leventhal, J.S., and Hosterman, J.W., 1982, Chemical and 

mineralogical analysis of Devonian black shale samples from 

Martin County, Kentucky; Carroll and Washington Counties, 

Ohio; Wise County, Virginia; and Overton County, Tennessee, USA: Chemical Geology, v. 37, p. 239-264. 

Leventhal, J.S., and Knapp, T.A., 1988, Preliminary microexamination of polished thin sections of Devonian black shales 

from the Appalachian Basin by optical microscopy, electron 

micro-probe and fission track methods, in Lasave, J., Gabriel, Z., eds., Proceedings of the IGCP 254 Inaugural 

Meeting, October 1987 in Jesenik, Czechoslovakia: Geological Survey, Prague, p. 57-65. 

Lister, Brian, 1982, Evaluation of analytical data-A practical 

guide for geoanalysts: Geostandards Newsletter, v. 6, p. 

175-205. 

Michaelis, R.E., 1975, The SRM story at NBS in NBS Special 

Publication 408, p. 237-242. 

Natrella, M.G., 1963, Experimental statistics: National Bureau of 

Standards Handbook 91. 

Schultz, L.G., Tourtelot, H.A., Gill, J.R., and Boerngen, J.G., 

1980, Composition and properties of the Pierre shale and 

equivalent rocks, Northern Great Plains region: Geological 

Survey Professional Paper 1064-B, p. B1-B2. 

Shapiro, Leonard, and Brannock, W.W., 1962, Rapid analysis of 

silicate, carbonate, and phosphate rocks: U.S. Geological 

Survey Bulletin 1144-A, 56 pp. 

Siegel, Sidney, 1956, Nonparametric statistics for the behavioral 

sciences: New York, McGraw-Hill, p. 47-52. 

Uriano, G.A., and Gravatt, C.C., 1977, The role of reference 

materials and reference methods in chemical analysis: CRC 

Critical Review in Analytical Chemistry, v. 6, p. 361-441. 

Y ouden, W. J. , 1960, The sample, the procedure, and the laboratory: Analytical Chemistry, v. 32, p. 23A-37 A. 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A 13 
APPENDIX 1. 

MAJOR/MINOR OXIDES: LABORATORY METHODS AND AVERAGES 

Lab code/ 

method 

Si02 data 

20- ........................................ . 

30- ........................................ . 

19- ........................................ . 

3-ICP ...................................... . 

2-XRF ..................................... . 

57-XRF .................................... . 

6-XRF ..................................... . 

4-RR ....................................... . 

15-COLOR ................................. . 

17-RR ..................................... . 

24-XRF .................................... . 

21-XRF .................................... . 

23-XRF .................................... . 

28-XRF .................................... . 

16-XRF .................................... . 

25-0ES .................................... . 

13-XRF .................................... . 

58-ICP ..................................... . 

14-CHEM .................................. . 

26-XRF .................................... . 

18-XRF .................................... . 

27-GRAV .................................. . 

36-ICP ..................................... . 

37- ........................................ . 

34- ........................................ . 

31- ........................................ . 

60-XRF .................................... . 

33- ........................................ . 

5-XRF ..................................... . 

1-RR ....................................... . 

32- ........................................ . 

29-COLOR ................................. . 

_11-0ES .................................... . 

Weight percent 

in sample 

23.00 

30.72 

48.10 

48.29 

48.43 

48.50 

48.57 

48.67 

48.73 

48.77 

48.86 

48.94 

49.00 

49.00 

49.15 

49.22 

49.24 

49.28 

49.45 

49.56 

49.56 

49.90 

49.90 

49.90 

49.90 

49.91 

49.91 

49.95 

50.05 

50.05 

50.06 

50.50 

54.53 

A14 The USGS Reference Sample Devonian Ohio Shale SD0-1 

Lab code/ 

method 

11-0ES .................................... . 

24-XRF .................................... . 

12-NAA .................................... . 

20- ........................................ . 

22-ICP ..................................... . 

37- ........................................ . 

23-XRF .................................... . 

33- ........................................ . 

31- ........................................ . 

60-XRF .................................... . 

15-COLOR ................................. . 

14-CHEM .................................. . 

17-RR ..................................... . 

36-ICP ..................................... . 

6-XRF ..................................... . 

2-XRF ..................................... . 

7-ICP ...................................... . 

3-ICP ...................................... . 

26-XRF .................................... . 

4-RR ....................................... . 

50-ICP ..................................... . 

19- ........................................ . 

18-XRF .................................... . 

13-XRF .................................... . 

27-AAS .................................... . 

57-XRF .................................... . 

58-XRF .................................... . 

21-XRF .................................... . 

16-XRF .................................... . 

28-XRF .................................... . 

8-ICP ...................................... . 

63-ICPMS .................................. . 

25-0ES .................................... . 

29-AAS .................................... . 

5-XRF ..................................... . 

Weight percent 

in sample 

11.34 

11.65 

11.68 

11.70 

11.88 

12.00 

12.00 

12.00 

12.04 

12.04 

12.08 

12.08 

12.08 

12.10 

12.10 

12.14 

12.29 

12.32 

12.33 

12.34 

12.38 

12.38 

12.43 

12.44 

12.50 

12.50 

12.50 

12.51 

12.55 

12.60 

12.67 

12.67 

12.68 

12.70 

13.02 

34- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.10 

35-AA . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.10 

1-RR........................................ 13.11 

32- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.01 

30-NAA..................................... 17.45 
Lab code/ 

method 

32- ........................................ . 

30-NAA .................................... . 

20- ........................................ . 

15-COLOR ................................. . 

31- ........................................ . 

25-0ES .................................... . 

22-ICP ..................................... . 

19- ........................................ . 

9-NAA ..................................... . 

16-XRF .................................... . 

8-ICP ...................................... . 

2-XRF ..................................... . 

4-RR ....................................... . 

13-XRF .................................... . 

37- ........................................ . 

14-CHEM .................................. . 

1-RR ....................................... . 

21-XRF .................................... . 

5-XRF ..................................... . 

6-XRF ..................................... . 

63-ICPMS .................................. . 

33- ........................................ . 

60-NAA .................................... . 

10-NAA .................................... . 

50-ICP ..................................... . 

55-NAA .................................... . 

17-RR ..................................... . 

57-XRF .................................... . 

28-XRF .................................... . 

27-COLOR ................................. . 

7-ICP ...................................... . 

11-0ES .................................... . 

58-ICP ..................................... . 

18-XRF .................................... . 

29-XRF .................................... . 

36-ICP ..................................... . 

26-XRF .................................... . 

24-XRF .................................... . 

60-AAS .................................... . 

35-AAS .................................... . 

34- ........................................ . 

12-NAA .................................... . 

56-NAA .................................... . 

Weight percent 

in sample 

0.28 

2.31 

8.30 

8.30 

8.60 

8.82 

9.01 

9.14 

9.15 

9.15 

9.15 

9.16 

9.17 

9.19 

9.22 

9.22 

9.34 

9.34 

9.38 

9.41 

9.41 

9.43 

9.43 

9.44 

9.45 

9.45 

9.49 

9.49 

9.50 

9.54 

9.54 

9.54 

9.55 

9.58 

9.60 

9.65 

9.66 

9.70 

9.71 

9.75 

9.76 

10.12 

10.19 

* For reporting of total iron only; does not accurately represent iron 

speciation in sample. 

FeO data 

Lab code/ Weight percent 

method in sample 

24-CHEM................................... 1.31 

3-CHEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.25 

19-CHEM................................... 2.94 

14-CHEM................................... 5.63 

Lab code/ Weight percent 

method in sample 

14-CHEM................................... 3.03 

3-CHEM.................................... 7.17 

24-CHEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8. 26 

CaO data 

Lab code/ Weight percent 

method in sample 

36-ICP...................................... 0.11 

30-NAA..................................... .13 

11-0ES..................................... .84 

33- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89 

23-XRF.................. .. . . . . . . . . . . . . . . . . . .90 

8-ICP....................................... .96 

24-XRF.................. .. . . . . . . . . . . . . . . . . . .97 

25-0ES..................................... .97 

12-NAA..................................... 1.01 

31- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.01 

37- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.01 

60-XRF..................................... 1.01 

21-XRF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.03 

50-ICP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.04 

2-XRF...................................... 1.05 

29-AAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.05 

16-XRF..................................... 1.05 

13-XRF..................................... 1.05 

58-ICP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.06 

14-CHEM................................... 1.06 

19- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.06 

32- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.06 

26-XRF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.06 

18-XRF..................................... 1.06 

1-RR........................................ 1.06 

6-XRF...................................... 1.07 

15-AAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.08 

7-ICP....................................... 1.08 

5-XRF...................................... 1.09 

28-XRF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.10 

57-XRF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.10 

17-RR...................................... 1.11 

22-ICP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.12 

27-CHEM........................ .. ......... 1.12 

4-RR........................................ 1.13 

34- ........................................ . 

35-AAS .................................... . 

3-ICP ...................................... . 

20- ........................................ . 

1.20 

1.20 

1.37 

1.60 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A 15 
MgO data 

Lab code/ Weight percent Lab code/ Weight percent 

method in sample method in sample 

37- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.29 26-XRF..................................... 0.25 

31- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.29 24-XRF..................................... .26 

60-XRF..................................... 1.29 22-ICP...................................... .29 

26-XRF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.43 4-RR........................................ .33 

12-NAA.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.45 13-XRF..................................... .34 

36-ICP...................................... 1.47 25-0ES..................................... .35 

14-AAS..................................... 1.48 6-XRF...................................... .35 

25-0ES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.49 32- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36 

58-ICP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.49 10-NAA..................................... .36 

33- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.51 15-FP....................................... .37 

29-AAS..................................... 1.51 57-XRF..................................... .37 

13-XRF..................................... 1.52 2-XRF........... .. . . . . . . . . . . . . . . . . . . . . . . . . . .37 

19- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.52 17-RR...................................... .37 

8-ICP....................................... 1.52 58-AAS..................................... .38 

17-RR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.53 9-NAA..... .. . . . . .. . . . . .. . . . . . . . . . . . . .. .. .. . .38 

21-XRF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.53 12-NAA..................................... .38 

28-AAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.53 8-ICP....................................... .38 

6-XRF...................................... 1.54 7-ICP....................................... .38 

7-ICP....................................... 1.54 16-XRF..................................... .38 

5-XRF...................................... 1.54 29-AAS..................................... .38 

2-XRF...................................... 1.55 31- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38 

1-RR........................................ 1.55 37- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38 

4-RR........................................ 1.57 18-XRF..................................... .39 

50-ICP.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.57 55-NAA................................ .. . . . .39 

15-AAS..................................... 1.57 50-ICP...................................... .39 

18-XRF..................................... 1.59 26-XRF................................ .. . . . .39 

35-AAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.59 1-RR............................ .. . . . . . . . . . . .40 

24-XRF . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.59 5-FP........................................ .42 

34- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.59 27-AAS..................................... .42 

27-CHEM................................... 1.59 36-ICP...................................... .42 

20- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.60 56-NAA............ ........... ... .. . . .. . . . . . .42 

57-XRF..................................... 1.60 14-AAS..................................... .43 

11-0ES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.63 19- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .44 

16-XRF..................................... 1.65 11-0ES..................................... .44 

22-ICP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1. 66 21-XRF..................................... .51 

3-ICP....................................... 1.74 20-......................................... .60 

32- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.81 35-AAS..................................... .60 

34-......................................... .60 

23-XRF..................................... .67 

3-ICP....................................... .95 

A 16 The USGS Reference Sample Devonian Ohio Shale SD0-1 
Ti02 data 

Lab code/ Weight percent Lab code/ Weight percent 

method in sample method in sample 

30-NAA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.68 30-NAA.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.34 

22-ICP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2. 79 7-ICP....................................... .48 

25-0ES..................................... 2.80 50-ICP...................................... .48 

15-FM...................................... 2.95 3-ICP....................................... .51 

23-XRF..................................... 3.00 29-COLOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .60 

31- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.06 23-XRF..................................... .60 

60-XRF..................................... 3.06 12-NAA..................................... .62 

4-RR........................................ 3.16 11-0ES..................................... .63 

13-XRF..................................... 3.18 25-0ES..................................... .63 

19- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.20 17-RR...................................... .67 

14-CHEM................................... 3.23 2-XRF...................................... .68 

2-XRF...................................... 3.24 20- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68 

12-NAA..................................... 3.27 19- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .68 

37- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.29 13-XRF..................................... .68 

16-XRF..................................... 3.29 36-ICP...................................... .69 

6-XRF...................................... 3.29 24-XRF................................ .. . . . .69 

28-XRF..................................... 3.30 28-XRF................................ .. . . . .69 

21-XRF..................................... 3.31 4-RR........................................ .70 

50-ICP...................................... 3.34 22-ICP...................................... .70 

26-XRF..................................... 3.35 6-XRF...................................... .70 

55-NAA..................................... 3.35 32- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .70 

17-RR...................................... 3.36 21-XRF..................................... .70 

36-ICP...................................... 3.36 16-XRF..................................... .70 

33- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.37 15-0ES..................................... .70 

27-AAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.37 15-COLOR. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72 

7-ICP....................................... 3.37 14-CHEM.......... .. . . . . .. .. . . . . .. . . . . .. . . . .72 

18-XRF..................................... 3.37 8-ICP....................................... .73 

1-RR........................................ 3.39 1-RR........................................ .73 

5-FP........................................ 3.40 58-ICP...................................... .74 

35-AAS..................................... 3.41 18-XRF..................................... .74 

34- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.41 27-COLOR.................................. .74 

24-XRF..................................... 3.43 37- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .74 

55-NAA..................................... 3.44 57-XRF..................................... .74 

60-NAA..................................... 3.45 60-XRF..................................... .74 

32- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.46 5-XRF...................................... .75 

31- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.51 31- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 

3-ICP....................................... 3.60 26-XRF..................................... .78 

20- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.70 35-AAS..................................... 1.01 

11-0ES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3.82 

8-ICP....................................... 4.60 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A 17 
Lab code/ 

method 

18-XRF .................................... . 

3-ICP ...................................... . 

19- ........................................ . 

21-XRF .................................... . 

20- ........................................ . 

34- ........................................ . 

28-COLOR ................................. . 

35-AAS .................................... . 

37- ........................................ . 

60-XRF .................................... . 

14-CHEM .................................. . 

5-COLOR .................................. . 

15-COLOR ................................. . 

27-COLOR ................................. . 

13-XRF .................................... . 

22-ICP ..................................... . 

33- ........................................ . 

2-XRF ..................................... . 

24-XRF .................................... . 

36-ICP ..................................... . 

16-XRF .................................... . 

58-COLOR ................................. . 

7-ICP ...................................... . 

29-COLOR ................................. . 

6-XRF ..................................... . 

4-RR ....................................... . 

26-XRF .................................... . 

57-XRF .................................... . 

8-ICP ...................................... . 

1-RR ....................................... . 

50-ICP ..................................... . 

17-RR ..................................... . 

25-0ES .................................... . 

11-0ES .................................... . 

Weight percent 

in sample 

0.07 

. 07 

. 08 

. 09 

. 10 

. 10 

. 10 

. 10 

. 10 

. 10 

.10 

. 11 

. 11 

. 11 

. 11 

. 11 

. 11 

. 11 

. 11 

. 11 

. 11 

. 11 

. 12 

. 12 

. 12 

. 12 

.12 

. 12 

. 13 

. 14 

.14 

.15 

.24 

.29 

A 18 The USGS Reference Sample Devonian Ohio Shale SD0-1 

Lab code/ 

method 

MnO data 

6-XRF ..................................... . 

25-0ES .................................... . 

26-XRF .................................... . 

3-ICP ...................................... . 

1-RR ....................................... . 

7-ICP ...................................... . 

25-AAS .................................... . 

13-XRF .................................... . 

11-0ES .................................... . 

58-ICP ..................................... . 

18-XRF .................................... . 

15-0ES .................................... . 

36-ICP ..................................... . 

4-RR ....................................... . 

17-RR ..................................... . 

21-XRF .................................... . 

37- ........................................ . 

28-XRF .................................... . 

14-AAS .................................... . 

36-ICP ..................................... . 

50-ICP ..................................... . 

35-AAS .................................... . 

29-AAS .................................... . 

12-NAA .................................... . 

37- ........................................ . 

27-AAS .................................... . 

8-ICP ...................................... . 

22-ICP ..................................... . 

19- ........................................ . 

2-XRF ..................................... . 

24-XRF .................................... . 

Weight percent 

in sample 

0.030 

.030 

.031 

.032 

.038 

.039 

.039 

.039 

.039 

.039 

.039 

.040 

.040 

.040 

.040 

.040 

.040 

.040 

.041 

.041 

.041 

.042 

.042 

.043 

.043 

.043 

.046 

.046 

.050 

.050 

.080 
Lab code/ 

method 

LOI data 

3-GRAV ................................... . 

1-GRAV ................................... . 

27-GRAV .................................. . 

13-GRAV .................................. . 

18-GRAV .................................. . 

58-GRAV .................................. . 

16-GRAV .................................. . 

6-GRAV ................................... . 

4-GRAV ................................... . 

17-GRAV .................................. . 

21-GRAV .................................. . 

15-GRAV .................................. . 

57-GRAV .................................. . 

26-GRAV .................................. . 

19-GRAV .................................. . 

2-GRAV ................................... . 

22-GRAV .................................. . 

20-GRAV .................................. . 

Lab code/ 

method 

CToT data 

20- ........................................ . 

27- ........................................ . 

7-.......................................... . 

6-.......................................... . 

19- ........................................ . 

13- ........................................ . 

8-.......................................... . 

28- ........................................ . 

14- ........................................ . 

23- ........................................ . 

Weight percent 

in sample 

19.56 

19.56 

19.78 

20.83 

20.91 

21.37 

21.38 

21.57 

21.63 

21.82 

21.90 

21.93 

22.00 

22.35 

22.37 

22.84 

23.08 

33.00 

Weight percent 

in sample 

8.97 

9.27 

9.85 

9.96 

9.96 

9.96 

9.98 

10.00 

10.26 

10.36 

29- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.40 

30- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.40 

34- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.40 

32- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.43 

60-COMB. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.53 

38- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10.89 

39- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.80 

31- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.79 

Lab code/ 

rejection method 

Hydrogen (percent) 

39- ........................................ . 

30- ........................................ . 

38- ........................................ . 

23- ........................................ . 

32- ........................................ . 

This work .................................. . 

34- ........................................ . 

29- ........................................ . 

55- ........................................ . 

31- ........................................ . 

Nitrogen (percent) 

Weight percent 

in sample 

1.24 

1.30 

1.30 

1.33 

1.34 

1.34 

1.35 

1.40 

1.45 

1.83 

Lab code/ Weight percent 

rejection method in sample 

31- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 0.31 

38- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .31 

34- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .32 

This work . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .33 

32- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .34 

23- ........................................ . 

30- ........................................ . 

39- ........................................ . 

Constitutional water (percent) 

.40 

.40 

1.21 

Lab code/ Weight percent 

rejection method in sample 

Compilation average.......................... 2.93 

17- . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.41 

14-......................................... 7.12 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A 19 
APPENDIX 2. 

TRACE ELEMENTS: LABORATORY METHODS AND AVERAGES 

Lab code/ 

method 

Ag data 

15-AAS .................................... . 

15-0ES .................................... . 

58-AAS .................................... . 

27-0ES .................................... . 

3-ICP ...................................... . 

57-DCP .................................... . 

7-ICP ...................................... . 

11-0ES .................................... . 

42-0ES .................................... . 

12-NAA .................................... . 

Lab code/ 

method 

As data 

3-ICP ...................................... . 

7-HYD ..................................... . 

14--XRF .................................... . 

21-XRF .................................... . 

7-ICP ...................................... . 

10-NAA .................................... . 

50-ICP ..................................... . 

57-FAA .................................... . 

8-ICP ...................................... . 

12-NAA .................................... . 

29-HGA .................................... . 

60-NAA .................................... . 

55-NAA .................................... . 

46-HGA .................................... . 

58-AAS .................................... . 

23-HGA .................................... . 

Lab code/ 

method 

Au data 

15-AAS .................................... . 

23-NAA .................................... . 

13-XRF .................................... . 

12-NAA .................................... . 

58-AAS .................................... . 

57-DCP .................................... . 

7-ICP ...................................... . 

f,Lg/g 

in sample 

0.0944 

. 1650 

<.40 

<.40 

<.50 

<.50 

<2 

<2 

<3 

<4 

f,Lg/g 

in sample 

<10.0 

38 

50.3 

55.0 

62.5 

62.7 

66.1 

69.0 

72.5 

72.8 

74.0 

79 

79.0 

79.8 

100 

104 

f.Lg/g 

in sample 

0.0014 

.0020 

.0035 

<.010 

<.10 

<2 

<8 

A20 The USGS Reference Sample Devonian Ohio Shale SD0-1 

Lab code/ 

method 

8 data 

3-ICP ...................................... . 

15-0ES .................................... . 

27-0ES .................................... . 

60-0ESa ................................... . 

16-0ES .................................... . 

11-0ES .................................... . 

57-DCP .................................... . 

60-0ESc ................................... . 

42-0ES .................................... . 

40-0ES .................................... . 

Lab code/ 

method 

Ba data 

3-ICP ...................................... . 

21-XRF .................................... . 

22-ICP ..................................... . 

40-0ES .................................... . 

11-0ES .................................... . 

2-XRF ..................................... . 

12-NAA .................................... . 

17-ICP ..................................... . 

13-XRF .................................... . 

43-XRF .................................... . 

15-0ES .................................... . 

15-AAS .................................... . 

41-XRF .................................... . 

10-NAA .................................... . 

7-ICP ...................................... . 

8-ICP ...................................... . 

27-ICP ..................................... . 

44--XRF .................................... . 

26-ICP ..................................... . 

15-XRF .................................... . 

24--XRF .................................... . 

57-XRF .................................... . 

58-ICP ..................................... . 

42-0ES .................................... . 

55-NAA .................................... . 

10-NAA .................................... . 

27-0ES .................................... . 

9-NAA ..................................... . 

15-0ES .................................... . 

25-0ES .................................... . 

f,Lg/g 

in sample 

92.5 

120 

120 

120 

129 

130 

130 

140 

145 

170 

f.Lg/g 

in sample 

211 

318 

335 

360 

363 

369 

380 

381 

385 

388 

390 

398 

403 

403 

407 

415 

420 

424 

431 

444 

473 

481 

495 

529 

550 

598 

600 

633 

640 

743 
Lab code/ 

method 

Be data 

58-ICP ..................................... . 

8-ICP ...................................... . 

22-ICP ..................................... . 

17-ICP ..................................... . 

7-ICP ...................................... . 

15-0ES .................................... . 

50-ICP ..................................... . 

16-0ES .................................... . 

26-ICP ..................................... . 

2-AAS ..................................... . 

11-0ES .................................... . 

57-DCP .................................... . 

40-0ES .................................... . 

Lab code/ 

method 

Bi data 

57-DCP .................................... . 

2-XRF ..................................... . 

3-ICP ...................................... . 

7-ICP ...................................... . 

21-XRF .................................... . 

Lab code/ 

method 

Br data 

12-NAA .................................... . 

60-NAA .................................... . 

Lab code/ 

method 

Cd data 

57-DCP .................................... . 

29-HGA .................................... . 

58-ICP ..................................... . 

7-ICP ...................................... . 

11-0ES .................................... . 

J.Lg/g 

in sample 

2.00 

2.75 

2.78 

2.93 

3.00 

3.01 

3.09 

3.48 

3.85 

4.0 

4.25 

5.00 

5.83 

J.Lg/g 

in sample 

0.2 

<2 

<10 

<10 

<30 

J.Lg/g 

in sample 

5 

3.6 

J.Lg/g 

in sample 

<0.2 

<.5 

1 

<2 

<3 

27-ICP...................................... 7 

21-XRF..................................... <20 

Lab code/ 

method 

Ce data 

3-ICP ...................................... . 

7-NAA ..................................... . 

14-EXTRIICP .............................. . 

26-ICP ..................................... . 

50-ICP ..................................... . 

2-XRF ..................................... . 

7-ICP ...................................... . 

9-NAA ..................................... . 

14-SEPN/ICP ............................... . 

41-XRF .................................... . 

49-SEPN/ICP ............................... . 

43-XRF .................................... . 

57-ICPMS .................................. . 

56-NAA .................................... . 

8-NAA ..................................... . 

8-ICP ...................................... . 

24-SEPN/ICP ............................... . 

63-ICPMS .................................. . 

17-SEPN/ICP ............................... . 

7-SEPN/ICP ................................ . 

60-NAA .................................... . 

44-XRF .................................... . 

10-NAA .................................... . 

40-0ES .................................... . 

11-0ES .................................... . 

5-NAA ..................................... . 

15-NAA .................................... . 

16-0ES .................................... . 

13-XRF .................................... . 

21-XRF .................................... . 

24-XRF .................................... . 

12-NAA .................................... . 

Lab code/ 

method 

Cl data 

60-XRF .................................... . 

55-NAA .................................... . 

12-NAA .................................... . 

J.Lg/g 

in sample 

63.0 

64.0 

65.0 

68.0 

68.7 

70.0 

70.5 

70.8 

71.3 

71.8 

71.8 

72.3 

73.2 

73.7 

74.2 

75.0 

76.2 

76.2 

76.7 

76.8 

77.4 

78.5 

78.5 

80.2 

84.0 

85.0 

87.3 

87.5 

89.7 

90.0 

92.0 

100 

f.Lg/g 

in sample 

90 

94 

116 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A21 
Lab code/ 

method 

Co data 

60-0ESc ................................... . 

40-0ES .................................... . 

25-0ES .................................... . 

2-XRF ..................................... . 

5-AAS ..................................... . 

21-XRF .................................... . 

11-0ES .................................... . 

22-ICP ..................................... . 

25-AAS .................................... . 

17-ICP ..................................... . 

5-NAA ..................................... . 

9-NAA ..................................... . 

60-NAA .................................... . 

26--ICP ..................................... . 

10-NAA .................................... . 

58-ICP ..................................... . 

45-AAS .................................... . 

12-NAA .................................... . 

3-ICP ...................................... . 

8-ICP ...................................... . 

56--NAA .................................... . 

60-0ESa ................................... . 

27-0ES .................................... . 

24-XRF .................................... . 

7-ICP ...................................... . 

50-ICP ..................................... . 

57-ICP ..................................... . 

27-ICP ..................................... . 

42-0ES .................................... . 

15-0ES .................................... . 

15-NAA .................................... . 

23-AAS .................................... . 

Cr data 

J.Lg/g Lab code/ 

in sample method 

35 42-0ES .................................... . 

36.5 60-0ESc ................................... . 

37.5 25-0ES .................................... . 

39.8 11-0ES .................................... . 

40.0 60-0ESa ................................... . 

40.0 40-0ES .................................... . 

40.3 57-DCP .................................... . 

41.8 3-ICP ...................................... . 

42.0 9-NAA ..................................... . 

42.5 14-XRF .................................... . 

43.1 26--ICP ..................................... . 

43.5 55-NAA .................................... . 

44 60-NAA .................................... . 

44.0 13-XRF .................................... . 

44.4 10-NAA .................................... . 

44.5 58-ICP ..................................... . 

46.5 8-ICP ...................................... . 

46.8 41-XRF .................................... . 

47.0 50-ICP ..................................... . 

48.0 27-ICP ..................................... . 

48.9 22-ICP ..................................... . 

49 21-XRF .................................... . 

50.0 56--NAA .................................... . 

51.0 17-ICP ..................................... . 

51.3 23-0ES .................................... . 

51.4 12-NAA .................................... . 

52.0 7-ICP ...................................... . 

52.0 15-ICP ..................................... . 

53.0 44-XRF .................................... . 

53.0 2-XRF ..................................... . 

56.3 29-HGA .................................... . 

57.0 15-NAA .................................... . -------------------- 27-0ES .................................... . 

43-XRF .................................... . 

24-XRF .................................... . 

A22 The USGS Reference Sample Devonian Ohio Shale SD0-1 

J,Lg/g 

in sample 

47.8 

50 

51.5 

55.8 

56 

56.2 

58.0 

59.0 

59.6 

60.3 

61.0 

61.0 

61 

64.3 

64.5 

65.0 

65.0 

66.3 

66.3 

67.0 

67.0 

68.4 

69.3 

70.0 

70.0 

71.6 

71.8 

73.0 

74.8 

75.3 

77.0 

78.0 

80.0 

95.8 

103 
Lab code/ 

method 

Cs data 

57-NAA .................................... . 

5-NAA ..................................... . 

9-NAA ..................................... . 

10-NAA .................................... . 

56-NAA .................................... . 

60-NAA .................................... . 

12-NAA .................................... . 

2-XRF ..................................... . 

15-NAA .................................... . 

5-FLPHO .................................. . 

Lab code/ 

method 

Cu data 

4--XRF ..................................... . 

21-XRF .................................... . 

57-DCP .................................... . 

2-XRF ..................................... . 

28-XRF .................................... . 

45-AAS .................................... . 

14--XRF .................................... . 

58-ICP ..................................... . 

43-XRF .................................... . 

5-AAS ..................................... . 

60-0ESc ................................... . 

7-ICP ...................................... . 

26-ICP ..................................... . 

41-XRF .................................... . 

8-ICP ...................................... . 

50-ICP ..................................... . 

44--XRF .................................... . 

15-0ES .................................... . 

27-0ES .................................... . 

15-AAS .................................... . 

22-ICP ..................................... . 

3-ICP ...................................... . 

60-AAS .................................... . 

11-0ES .................................... . 

29-HGA .................................... . 

16-0ES .................................... . 

60-0ESa ................................... . 

23-AAS .................................... . 

17-ICP ..................................... . 

27-AAS .................................... . 

40-0ES .................................... . 

42-0ES .................................... . 

j.Lg/g 

in sample 

5.00 

5.23 

5.97 

6.42 

6.97 

7 

7.32 

7.75 

8.65 

11.5 

j.Lg/g 

in sample 

29.0 

37.0 

46.0 

47.5 

50.0 

50.3 

51.8 

53.5 

54.3 

54.5 

55 

56.8 

58.0 

58.3 

58.3 

58.7 

59.3 

60.0 

60.0 

61.0 

61.3 

62.0 

63 

64.8 

67.0 

69.5 

73 

74.0 

74.5 

75.0 

75.5 

225 

Lab code/ 

method 

Dy data 

3-ICP ...................................... . 

8-SEPN/ICP ................................ . 

57-ICPMS .................................. . 

63-ICPMS .................................. . 

26-SEPN/ICP ............................... . 

24-SEPN/ICP ............................... . 

49-SEPN/ICP ............................... . 

14--SEPN/ICP ............................... . 

12-NAA .................................... . 

17-SEPN/ICP ............................... . 

7-NAA ..................................... . 

60-NAA .................................... . 

14-EXTRIICP .............................. . 

7-SEPN/ICP ................................ . 

Lab code/ 

method 

Er data 

8-SEPN/ICP ................................ . 

7-SEPN/ICP ................................ . 

49-SEPN/ICP ............................... . 

26-SEPN/ICP ............................... . 

57-ICPMS .................................. . 

17-SEPN/ICP ............................... . 

14-SEPN/ICP ............................... . 

14--SEPN/ICP ............................... . 

3-ICP ...................................... . 

Lab code/ 

method 

Eu data 

3-ICP ...................................... . 

9-NAA ..................................... . 

5-NAA ..................................... . 

10-NAA .................................... . 

14-SEPN/ICP ............................... . 

7-NAA ..................................... . 

12-NAA .................................... . 

49-SEPN/ICP ............................... . 

14--EXTRIICP .............................. . 

24-SEPN/ICP ............................... . 

50-ICP ..................................... . 

63-ICPMS .................................. . 

26-SEPN/ICP ............................... . 

57-ICPMS .................................. . 

8-SEPN/ICP ................................ . 

56-NAA .................................... . 

60-NAA .................................... . 

17-SEPN/ICP ............................... . 

7-ICP ...................................... . 

7-SEPN/ICP ................................ . 

15-NAA .................................... . 

j.Lg/g 

in sample 

4.75 

5.20 

5.80 

5.90 

6.00 

6.07 

6.10 

6.25 

6.50 

6.72 

6.90 

7.1 

7.11 

7.30 

j.Lg/g 

in sample 

2.90 

3.10 

3.26 

3.40 

3.40 

3.55 

3.81 

3.98 

4.75 

j.Lg/g 

in sample 

<1 

1.43 

1.46 

1.47 

1.47 

1.50 

1.63 

1.65 

1.67 

1.68 

1.68 

1.68 

1.70 

1.71 

1.72 

1.77 

1.9 

1.95 

<2 

2.0 

2.05 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A23 
Lab code/ 

method 

F data 

14- ........................................ . 

60-ISE ..................................... . 

55-ISE ..................................... . 

24-PIGE ................................... . 

18- ........................................ . 

4-ISE ...................................... . 

61-IC ...................................... . 

61-IC ...................................... . 

62-IC ...................................... . 

Lab code/ 

method 

Ga data 

3-ICP ...................................... . 

15-0ES .................................... . 

21-XRF .................................... . 

11-0ES .................................... . 

2-XRF ..................................... . 

50-ICP ..................................... . 

25-0ES .................................... . 

7-ICP ...................................... . 

8-ICP ...................................... . 

40-0ES .................................... . 

55-NAA .................................... . 

60-NAA .................................... . 

58-ICP ..................................... . 

23-0ES .................................... . 

12-NAA .................................... . 

57-ICP ..................................... . 

5-AAS ..................................... . 

Lab code/ 

method 

Gd data 

,..,gig 

in sample 

<100 

534 

590 

687 

720 

727 

742 

780 

808 

,..,gig 

in sample 

<10 

14.0 

15.0 

16.0 

16.5 

16.7 

16.8 

17.3 

17.3 

18.5 

19.0 

19 

<20.0 

20.0 

23.6 

24.0 

27.5 

~J.g/g 

in sample 

3-ICP....................................... 5.0 

26-SEPN/ICP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.1 

7-NAA..... .. ...... .... .. . . . . . . . . . . . . .. ..... 6.2 

8-NAA..... .. .... ........ ...... ... . . . . . . . . . . 6.9 

57-ICPMS................................... 6.9 

14-SEPN/ICP.... . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.1 

17-SEPN/ICP................................ 7.3 

24-SEPN/ICP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7. 8 

49-SEPN/ICP................................ 7.8 

63-ICPMS................................... 7.8 

14-EXTR/ICP............................... 8.1 

7-SEPN/ICP................................. 9.1 

8-SEPN/ICP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9. 7 

40-0ES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.5 

A24 The USGS Reference Sample Devonian Ohio Shale SD0-1 

Lab code/ 

method 

Hf data 

9-NAA ..................................... . 

5-NAA ..................................... . 

57-NAA .................................... . 

9-NAA ..................................... . 

10-NAA .................................... . 

2-XRF ..................................... . 

60-NAA .................................... . 

56-NAA .................................... . 

12-NAA .................................... . 

Lab code/ 

method 

Hg data 

27-0ES .................................... . 

57-CHEM .................................. . 

48-CVAA .................................. . 

3-ICP ...................................... . 

23-CVAA .................................. . 

47-CVAA .................................. . 

12-NAA .................................... . 

29-CVAA .................................. . 

Lab code/ 

method 

Ho data 

3-ICP ...................................... . 

8-SEPN/ICP ................................ . 

57-ICPMS .................................. . 

49-SEPN/ICP ............................... . 

14-SEPN/ICP ............................... . 

7-SEPN/ICP ................................ . 

26-SEPN/ICP ............................... . 

14-EXTR/ICP .............................. . 

7-ICP ...................................... . 

,..,gig 

in sample 

3.28 

3.90 

4.00 

4.03 

4.38 

4.50 

4.6 

4.62 

5.80 

,_.,g/g 

in sample 

<0.05 

.088 

.096 

.18 

.19 

.29 

1.3 

3.0 

,..,gig 

in sample 

<1 

1.07 

1.08 

1.14 

1.19 

1.2 

1.3 

1.38 

<4 
Lab code/ 

method 

La data 

44-XRF ........... : ........................ . 

50-ICP ..................................... . 

10-NAA .................................... . 

9-NAA ..................................... . 

2-XRF ..................................... . 

14-SEPN/1 .................................. . 

49-SEPN/1 .................................. . 

41-XRF .................................... . 

57-ICPMS .................................. . 

3-ICP ...................................... . 

24-XRF .................................... . 

63-ICPMS .................................. . 

7-NAA ..................................... . 

40-0ES .................................... . 

58-ICP ..................................... . 

15-0ES .................................... . 

7-SEPN/IC ................................. . 

43-XRF .................................... . 

17-ICP ..................................... . 

8-SEPN/IC ................................. . 

26-ICP ..................................... . 

14-EXTR/1 ................................. . 

7-ICP ...................................... . 

56-NAA .................................... . 

16-0ES .................................... . 

12-NAA .................................... . 

8-ICP ...................................... . 

15-NAA .................................... . 

13-XRF .................................... . 

5-NAA ..................................... . 

60-NAA .................................... . 

11-0ES .................................... . 

23-0ES .................................... . 

27-0ES .................................... . 

21-XRF .................................... . 

Lab code/ 

method 

Li data 

15-0ES .................................... . 

5-AAS ..................................... . 

27-ICP ..................................... . 

22-ICP ..................................... . 

60-AAS .................................... . 

57-AAS .................................... . 

50-ICP ..................................... . 

7-ICP ...................................... . 

8-ICP ...................................... . 

11-0ES .................................... . 

f,Lg/g 

in sample 

26.7 

33.1 

33.3 

33.7 

33.8 

35.0 

35.2 

35.5 

35.5 

35.5 

35.9 

35.9 

36.0 

36.2 

37.0 

37.0 

37.4 

37.5 

37.8 

37.9 

38.0 

38.5 

38.8 

39.1 

39.5 

40.2 

41.0 

41.5 

41.7 

42.8 

42.8 

45.3 

50.0 

<60 

70.0 

f,Lg/g 

in sample 

21.62 

22.5 

28.0 

31.2 

31.8 

32.0 

32.7 

33.7 

34.2 

43.2 

Lab code/ 

method 

Lu data 

57-ICPMS .................................. . 

26-SEPN/ICP ............................... . 

7-SEPN/ICP ................................ . 

49-SEPN/ICP ............................... . 

8-SEPN/ICP ................................ . 

24-SEPN/ICP ............................... . 

63-ICPMS .................................. . 

17-SEPN/ICP ............................... . 

10-NAA .................................... . 

14-SEPN/ICP ............................... . 

9-NAA ..................................... . 

7-NAA ..................................... . 

60-NAA .................................... . 

14-EXTR/ICP .............................. . 

15-NAA .................................... . 

56-NAA .................................... . 

12-NAA .................................... . 

5-NAA ..................................... . 

3-ICP ...................................... . 

Lab code/ 

method 

Mo data 

50-ICP ..................................... . 

40-0ES .................................... . 

27-0ES .................................... . 

23-COLOR ................................. . 

7-ICP ...................................... . 

10-NAA .................................... . 

2-XRF ..................................... . 

27-ICP ..................................... . 

16-0ES .................................... . 

3-ICP ...................................... . 

15-0ES .................................... . 

22-ICP ..................................... . 

8-ICP ...................................... . 

11-0ES .................................... . 

58-ICP ..................................... . 

55-NAA .................................... . 

60-NAA .................................... . 

60-0ESc ................................... . 

12-NAA .................................... . 

29-COLOR ................................. . 

60-0ESa ................................... . 

28-XRF .................................... . 

14-XRF .................................... . 

44-XRF .................................... . 

f,Lg/g 

in sample 

0.42 

.43 

.43 

.44 

.45 

.45 

.45 

.47 

.48 

.49 

.50 

.53 

.54 

.55 

.63 

.68 

.69 

.96 

4.0 

f,Lg/g 

in sample 

108 

109 

120 

122 

122 

126 

131 

132 

133 

134 

140 

142 

148 

150 

150 

155 

157 

160 

161 

181 

190 

193 

198 

215 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A25 
Lab code/ 

method 

Nb data 

50-ICP ..................................... . 

8-ICP ...................................... . 

7-ICP ...................................... . 

40-0ES .................................... . 

24-XRF .................................... . 

14-XRF .................................... . 

17-ICP ..................................... . 

2-XRF ..................................... . 

41-XRF .................................... . 

22-ICP ..................................... . 

13-XRF .................................... . 

18-XRF .................................... . 

57-XRF .................................... . 

44-XRF .................................... . 

58-ICP ..................................... . 

43-XRF .................................... . 

11-0ES .................................... . 

Lab code/ 

method 

Nd data 

3-ICP ...................................... . 

10-NAA .................................... . 

5-NAA ..................................... . 

7-NAA ..................................... . 

14-SEPN/1 .................................. . 

50-ICP ..................................... . 

14-EXTR/1 ................................. . 

17-SEPN/I. ................................. . 

2-XRF ..................................... . 

49-SEPN/1 .................................. . 

j.t.g/g 

in sample 

5.3 

6.0 

6.3 

9.5 

10.0 

10.8 

12.0 

12.0 

12.3 

12.3 

12.3 

12.5 

17.0 

17.1 

20.0 

20.3 

<25 

~J.g/g 

in sample 

30.8 

32.2 

33.0 

35.0 

35.6 

35.7 

35.7 

36.2 

36.2 

36.3 

57-ICPMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37.0 

7-ICP....................................... 37.2 

56-NAA. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37.4 

63-ICPMS. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.2 

24-SEPN/ICP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38.3 

8-SEPN/IC.................................. 38.6 

15-NAA..................................... 38.8 

9-NAA...................................... 39.3 

7-SEPN/IC.................................. 39.4 

16-0ES . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40.0 

12-NAA.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40.4 

A26 The USGS Reference Sample Devonian Ohio Shale SD0-1 

Lab code/ 

method 

Ni data 

13-XRF .................................... . 

5-AAS ..................................... . 

25-AAS .................................... . 

40-0ES .................................... . 

58-ICP ..................................... . 

25-0ES .................................... . 

11-0ES .................................... . 

28-XRF .................................... . 

45-AAS .................................... . 

10-NAA .................................... . 

2-XRF ..................................... . 

26-ICP ..................................... . 

44-XRF .................................... . 

55-NAA .................................... . 

17-ICP ..................................... . 

42-0ES .................................... . 

57-DCP .................................... . 

27-0ES .................................... . 

15-0ES .................................... . 

41-XRF .................................... . 

14-XRF .................................... . 

43-XRF .................................... . 

27-ICP ..................................... . 

8-ICP ...................................... . 

7-ICP ...................................... . 

29-HGA .................................... . 

3-ICP ...................................... . 

15-AAS .................................... . 

22-ICP ..................................... . 

23-AAS .................................... . 

j.t.g/g 

in sample 

84.0 

86.3 

88.5 

89.3 

89.5 

89.9 

90.0 

90.0 

90.3 

91.8 

93.3 

94.0 

94.9 

98 

99.3 

99.8 

100 

100 

101 

102 

106 

108 

109 

110 

110 

111 

116 

117 

128 

128 
Lab code/ 

method 

Pb data 

27-0ES .................................... . 

11-0ES .................................... . 

23-0ES .................................... . 

14-XRF .................................... . 

5-AAS ..................................... . 

57-DCP .................................... . 

50-ICP ..................................... . 

15-0ES .................................... . 

7-ICP ...................................... . 

25-AAS .................................... . 

16-0ES .................................... . 

15-AAS .................................... . 

3-ICP ...................................... . 

2-XRF ..................................... . 

8-ICP ...................................... . 

60-AAS .................................... . 

40-0ES .................................... . 

45-AAS .................................... . 

60-0ESc ................................... . 

60-0ESa ................................... . 

28-AAS .................................... . 

42-0ES .................................... . 

Lab code/ 

method 

Pr data 

~g/g 

in sample 

10.0 

17.5 

20.0 

20.5 

21.0 

24.0 

25.2 

26.0 

28.0 

28.5 

29.5 

30.0 

30.5 

30.8 

31.8 

33 

34.5 

35.5 

37 

38 

40.0 

42.5 

~gig 

in sample 

14-SEPN/ICP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.0 

2-XRF.......................... .. . . . . . . . . . . 8.0 

14-EXTR/ICP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8.7 

57-ICPMS................................... 8.7 

49-SEPN/ICP................................ 9.2 

26-SEPN/ICP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.4 

8-SEPN/ICP................................. 9.5 

7-SEPN/ICP................................. 9.7 

3-ICP....................................... 13.8 

Lab code/ 

method 

Rb data 

58-XRF .................................... . 

25-0ES .................................... . 

2-XRF ..................................... . 

5-NAA ..................................... . 

44-XRF .................................... . 

14-XRF .................................... . 

24-XRF .................................... . 

41-XRF .................................... . 

10-XRF .................................... . 

17-ICP ..................................... . 

18-XRF .................................... . 

55-NAA .................................... . 

60-NAA .................................... . 

10-NAA .................................... . 

13-XRF .................................... . 

43-XRF .................................... . 

15-NAA .................................... . 

12-NAA .................................... . 

Lab code/ 

method 

Sb data 

57-AAS .................................... . 

9-NAA ..................................... . 

10-NAA .................................... . 

12-NAA .................................... . 

3-NAA ..................................... . 

~gig 

in sample 

114 

117 

117 

121 

122 

124 

124 

124 

125 

125 

126 

127 

127 

128 

132 

134 

149 

154 

~g/g 

in sample 

2.3 

4.12 

4.60 

4.77 

<10 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A27 
lab code/ 

method 

Sc data 

5-NAA ..................................... . 

50-ICP ..................................... . 

3-ICP ...................................... . 

22-ICP ..................................... . 

7-ICP ...................................... . 

57-ICP ..................................... . 

9-NAA ..................................... . 

40-0ES .................................... . 

10-NAA .................................... . 

11-0ES .................................... . 

14--SEPN/ICP ............................... . 

58-XRF .................................... . 

56-NAA .................................... . 

2-XRF ..................................... . 

17-ICP ..................................... . 

15-0ES .................................... . 

23-0ES .................................... . 

55-NAA .................................... . 

8-ICP ...................................... . 

15-NAA .................................... . 

lab code/ 

method 

Se data 

60-NAA .................................... . 

59-INAA ................................... . 

12-NAA .................................... . 

10-NAA .................................... . 

~gig 

in sample 

10.3 

11.8 

11.8 

12.0 

12.0 

12.0 

12.3 

12.6 

12.7 

12.8 

12.8 

14.0 

14.0 

14.3 

14.3 

14.4 

15.0 

15.2 

15.3 

18.3 

~g/g 

in sample 

1.9 

2.68 

3 

6.8 

A28 The USGS Reference Sample Devonian Ohio Shale SD0-1 

lab code/ 

method 

Sm data 

12-NAA .................................... . 

57-ICPMS .................................. . 

56-NAA .................................... . 

3-ICP ...................................... . 

26-SEPN/ICP ............................... . 

8-NAA ..................................... . 

14--SEPN/ICP ............................... . 

49-SEPN/ICP ............................... . 

24--SEPN/ICP ............................... . 

63-ICPMS .................................. . 

10-NAA .................................... . 

8-SEPN/ICP ................................ . 

9-NAA ..................................... . 

17-SEPN/ICP ............................... . 

15-NAA .................................... . 

14--EXTR/ICP .............................. . 

60-NAA .................................... . 

7-ICP ...................................... . 

5-NAA ..................................... . 

lab code/ 

method 

Sn data 

27-0ES .................................... . 

44--XRF .................................... . 

15-0ES .................................... . 

57-XRF .................................... . 

2-XRF ..................................... . 

~gig 

in sample 

6.4 

6.8 

7.41 

7 

7.5 

7.5 

7.5 

7.6 

7.6 

7.6 

7.7 

8.2 

8.3 

8.4 

8.6 

8.7 

8.7 

9.4 

13 

~g/g 

in sample 

2.5 

2.7 

3.2 

5.0 

3.3 

16-0ES..................................... 5.3 

14--XRF..................................... <7 

11-0ES..................................... <10 

3-ICP....................................... <10 

7-ICP....................................... <10 
Lab code/ 

method 

Sr data 

25-0ES .................................... . 

42-0ES .................................... . 

3-ICP ...................................... . 

44-XRF .................................... . 

27-0ES .................................... . 

11-0ES .................................... . 

14-XRF .................................... . 

13-XRF .................................... . 

57-XRF .................................... . 

21-XRF .................................... . 

2-XRF ..................................... . 

18-XRF .................................... . 

8-XRF ..................................... . 

24-XRF .................................... . 

41-XRF .................................... . 

43-XRF .................................... . 

22-ICP ..................................... . 

50-ICP ..................................... . 

17-ICP ..................................... . 

15-0ES .................................... . 

27-ICP ..................................... . 

8-ICP ...................................... . 

26-ICP ..................................... . 

55-NAA .................................... . 

40-0ES .................................... . 

16-0ES .................................... . 

23-0ES .................................... . 

Lab code/ 

method 

Ta data 

60-NAA .................................... . 

9-NAA ..................................... . 

10-NAA .................................... . 

5-NAA ..................................... . 

56-NAA .................................... . 

12-NAA .................................... . 

15-NAA .................................... . 

2-XRF ..................................... . 

2-XRF ..................................... . 

3-ICP ...................................... . 

7-ICP ...................................... . 

J.Lg/g 

in sample 

31.5 

41.5 

68.0 

68.3 

70.0 

72.0 

72.0 

72.7 

73.0 

73.0 

73.8 

74.5 

75.8 

76.0 

76.0 

76.0 

77.5 

78.3 

78.8 

80.0 

80.0 

80.3 

83.5 

93.0 

106.0 

128 

150 

J.Lg/g 

in sample 

1.1 

1.03 

1.07 

1.08 

1.08 

1.19 

1.36 

<3 

4 

<10 

<40 

Lab code/ 

method 

Tb data 

57-ICPMS .................................. . 

14-SEPN/ICP ............................... . 

14-EXTR/ICP .............................. . 

26-SEPN/ICP ............................... . 

7-SEPN/ICP ................................ . 

8-SEPN/ICP ................................ . 

60-NAA .................................... . 

7-NAA ..................................... . 

10-NAA .................................... . 

9-NAA ..................................... . 

15-NAA .................................... . 

56-NAA .................................... . 

49-SEPNIICP ............................... . 

5-NAA ..................................... . 

12-NAA .................................... . 

3-ICP ...................................... . 

Lab code/ 

method 

Th data 

57-NAA .................................... . 

50-ICP ..................................... . 

55-NAA .................................... . 

60-NAA .................................... . 

10-ICP ..................................... . 

9-NAA ..................................... . 

56-NAA .................................... . 

17-ICP ..................................... . 

5-NAA ..................................... . 

12-NAA .................................... . 

7-ICP ...................................... . 

15-NAA .................................... . 

3-ICP ...................................... . 

Lab code/ 

method 

Tm data 

57-ICPMS .................................. . 

27-0ES .................................... . 

8-SEPN/ICP ................................ . 

49-SEPN/ICP ............................... . 

26-SEPN/ICP ............................... . 

f,Lg/g 

in sample 

0.80 

.93 

.96 

1.00 

1.00 

1.00 

1.2 

1.10 

1.15 

1.16 

1.26 

1.28 

1.40 

1.46 

1.65 

3.25 

f,Lg/g 

in sample 

8.10 

9.20 

9.5 

9.5 

9.77 

9.82 

9.95 

10.35 

10.60 

10.62 

11.00 

11.21 

26.25 

f.Lg/g 

in sample 

0.30 

.34 

.34 

.44 

.46 

14-SEPN/ICP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49 

7-SEPN/ICP. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5 

7-NAA..... .. . . . . . . . . . . . . . . . . . . . . .. .. . ...... .55 

9-NAA........... .. . . . . .. . . . . . . .. .. .. . ... .. . .56 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A29 
lab code/ 

method 

U data 

57-NAA .................................... . 

3-ICP ...................................... . 

10-NAA .................................... . 

17-ICP ..................................... . 

50-ICP ..................................... . 

12-NAA .................................... . 

56-NAA .................................... . 

14-XRF .................................... . 

9-NAA ..................................... . 

29-NAA .................................... . 

15-NAA .................................... . 

55-NAA .................................... . 

60-NAA .................................... . 

28-NAA .................................... . 

23-DNA .................................... . 

2-XRF ..................................... . 

lab code/ 

method 

V data 

25-0ES .................................... . 

42-0ES .................................... . 

40-0ES .................................... . 

3-ICP ...................................... . 

15-AAS .................................... . 

8-ICP ...................................... . 

11-0ES .................................... . 

13-XRF .................................... . 

17-ICP ..................................... . 

57-DCP .................................... . 

58-ICP ..................................... . 

23-0ES .................................... . 

50-ICP ..................................... . 

26-ICP ..................................... . 

27-ICP ..................................... . 

12-NAA .................................... . 

21-XRF .................................... . 

29-COLOR ................................. . 

15-0ES .................................... . 

27-0ES .................................... . 

f.Lg/g 

in sample 

34.2 

40.5 

40.8 

43.2 

44.8 

46.2 

46.6 

48.5 

50.7 

51.0 

51.8 

52 

52 

54.0 

55.6 

61.5 

!J.g/g 

in sample 

88 

123 

133 

139 

145 

158 

158 

158 

159 

160 

160 

161 

164 

165 

166 

167 

168 

168 

170 

170 

2-XRF...................................... 172 

7-ICP....................................... 179 

22-ICP...................................... 179 

24-XRF.................. .. .. . . . . .. . . . . . . . . . 219 

28-AAS..................................... 266 

A30 The USGS Reference Sample Devonian Ohio Shale SD0-1 

lab code/ 

method 

Wdata 

16-0ES .................................... . 

2-XRF ..................................... . 

57-NAA .................................... . 

12-NAA .................................... . 

58-ICP ..................................... . 

27-0ES .................................... . 

lab code/ 

method 

Y data 

3-ICP ...................................... . 

57-ICP ..................................... . 

8-SEPN/ICP ................................ . 

40-0ES .................................... . 

49-ICP ..................................... . 

44-XRF .................................... . 

41-XRF .................................... . 

7-ICP ...................................... . 

14-SEPN/ICP ............................... . 

26-ICP ..................................... . 

24-XRF .................................... . 

50-ICP ..................................... . 

58-ICP ..................................... . 

18-XRF .................................... . 

7-NAA ..................................... . 

13-XRF .................................... . 

14-EXTR/ICP .............................. . 

8-ICP ...................................... . 

11-0ES .................................... . 

21-XRF .................................... . 

43-XRF .................................... . 

17-ICP ..................................... . 

16-0ES .................................... . 

22-ICP ..................................... . 

14-XRF .................................... . 

17-SEPN/ICP ............................... . 

2-XRF ..................................... . 

23-0ES .................................... . 

15-0ES .................................... . 

~J.g/g 

in sample 

<0.8 

<3 

<3 

3.34 

5 

<60 

f.Lg/g 

in sample 

29.0 

30.0 

31.0 

31.2 

31.2 

32.4 

32.5 

34.0 

34.9 

35.0 

35.0 

35.6 

36.5 

37.5 

39.7 

40.0 

40.4 

41.5 

41.8 

42.0 

42.3 

42.8 

43.8 

45.3 

45.5 

49.5 

49.8 

50.0 

50.0 
Lab code/ 

method 

Yb data 

26-SEPN/ICP ............................... . 

55-NAA .................................... . 

60-NAA .................................... . 

7-ICP ...................................... . 

3-ICP ...................................... . 

23-ICP ..................................... . 

50-ICP ..................................... . 

24-SEPN/ICP ............................... . 

63-ICPMS .................................. . 

14-SEPN/ICP ............................... . 

7-SEPN/ICP ................................ . 

49-SEPN/ICP ............................... . 

8-SEPN/ICP ................................ . 

9-NAA ..................................... . 

10-NAA .................................... . 

7-NAA ..................................... . 

57-ICPMS .................................. . 

56--NAA .................................... . 

17-ICP ..................................... . 

14-EXTR/ICP .............................. . 

12-NAA .................................... . 

15-NAA .................................... . 

15-0ES .................................... . 

40-0ES .................................... . 

16-0ES .................................... . 

tJ.g/g 

in sample 

2.80 

2.9 

2.9 

3.00 

3.00 

3.00 

3.01 

3.04 

3.04 

3.08 

3.10 

3.11 

3.15 

3.33 

3.39 

3.40 

3.40 

3.52 

3.55 

3.80 

3.92 

4.30 

5.00 

5.05 

5.23 

Lab code/ 

method 

Zn data 

12-NAA .................................... . 

15-0ES .................................... . 

17-ICP ..................................... . 

5-AAS ..................................... . 

14-XRF .................................... . 

21-XRF .................................... . 

7-ICP ...................................... . 

45-AAS .................................... . 

50-ICP ..................................... . 

28-AAS .................................... . 

43-XRF .................................... . 

10-NAA .................................... . 

8-ICP ...................................... . 

24-XRF .................................... . 

41-XRF .................................... . 

40-0ES .................................... . 

9-NAA ..................................... . 

29-HGA .................................... . 

58-ICP ..................................... . 

57-DCP .................................... . 

25-AAS .................................... . 

44-XRF .................................... . 

22-ICP ..................................... . 

2-XRF ..................................... . 

3-ICP ...................................... . 

tJ.g/g 

in sample 

<30 

50.0 

55.5 

55.8 

56.5 

57.0 

57.5 

59.3 

59.4 

60.0 

60.3 

61.0 

62.5 

64.0 

64.3 

65.0 

65.8 

67.0 

68.0 

70.0 

70.5 

71.3 

71.5 

71.8 

72.0 

27-AAS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 72.0 

15-0ES..................................... 73.0 

23-......................................... 76.0 

27-0ES..................................... 100 

Statistical Treatment of Contributed Data in the Derivation of Recommended Concentrations for Devonian Ohio Shale SD0-1 A31 
lab code/ 

method 

Zr data 

3-ICP ...................................... . 

40-0ES .................................... . 

60-0ESa ................................... . 

22-ICP ..................................... . 

23-0ES .................................... . 

41-XRF .................................... . 

2-XRF ..................................... . 

17-ICP ..................................... . 

44-XRF .................................... . 

16-0ES .................................... . 

18-XRF .................................... . 

43-XRF .................................... . 

14-XRF .................................... . 

26-ICP ..................................... . 

13-XRF .................................... . 

25-0ES .................................... . 

24-SEPN/ICP ............................... . 

57-XRF .................................... . 

60-0ESc ................................... . 

24-XRF .................................... . 

27-0ES .................................... . 

11-0ES .................................... . 

9-NAA ..................................... . 

12-NAA .................................... . 

f,Lg/g 

in sample 

101 

112 

130 

141 

150 

153 

156 

159 

160 

160 

163 

164 

167 

168 

169 

170 

171 

172 

181 

191 

230 

237 

318 

408 

A32 The USGS Reference Sample Devonian Ohio Shale SD0-1 
Chapter B 

Determination of Major and 

11 Trace Elements (XRF), Gold (MS), 

Carbon and Sulfur (COUL) in 

USGS Devonian Ohio Shale SD0-1 

By OTMAR SPIES, BERNHARD STRIBRNY, JOSEF 

KONOPASEK, and HANS URBAN 

U.S. GEOLOGICAL SURVEY BULLETIN 2046 

THE USGS REFERENCE SAMPLE DEVONIAN OHIO SHALE SD0-1 

CONTENTS 

Abstract Bl 

Introduction Bl 

Experiment Parameters Bl 

Determination of Major and Trace Elements by X-ray Fluorescence 

Analysis Bl 

Sample Preparation Bl 

Instrumentation B3 

Data Evaluation B3 

Loss on Ignition B4 

Determination of Gold by Graphite Furnace Atomic Absorption 

Spectrometry B4 

Determination of CARBONtotat' CARBONcarbonate' CARBONorganic' and 

SULFUR by Coulometric Titration BS 

Conclusions BS 

References B6 

FIGURES 

1. Flow diagram of analytical sequence for the analysis of SD0-1 B2 

2. Recommended average values for SD0-1 and their ranges of confidence in 

comparison to the mean values as reported in tables 3 and 4 B6 

TABLES 

1. Instrument set-up (Rh-tube) of major and trace element analyses B3 

2. The program parameters for the HGA-400 B4 

3. XRF determinations of major and trace elements in USGS Devonian Ohio Shale 

SD0-1 B4 

4. Coulometric determinations of CARBONtotal' CARBONcarbonate' CARBONorganic 

and SULFUR in USGS Devonian Ohio Shale SD0-1 BS 

5. Results for gold after fire assay preconcentration BS 

Determination of Major and 11 Trace Elements (XRF), 

Gold (AAS), Carbon and Sulfur (COUL) in USGS 

Devonian Ohio Shale SD0-1 

By Otmar Spies, Bernhard Stribrny, josef Konopasek, and Hans Urban 1 

Abstract 

An X-ray fluorescence (XRF) analytical program for 

the determination of 10 major and 11 trace elements in 

rock samples has been developed using a glass bead 32 

mm in diameter. The method was applied to the characterization of the shale SD0-1 as a reference sample in 

conjunction with the Metalliferous Black Shales Project of 

the International Geologic Congress. Additionally, loss on 

ignition and carbon and sulfur, using coulometry (COUL), 

were determined as major constituents in SD0-1; and 

trace gold was determined by graphite furnace atomic 

absorption spectrometry (MS) after fire assay preconcentration. The data were used in establishing recommended 

concentrations for constituents in the reference sample. 

INTRODUCTION 

As a contribution to the International Geologic Congress Project (IGCP) 254, "Metalliferous Black Shales," 

our working group investigated black-shale-hosted copper, 

gold, and lead-zinc deposits in the Northeastern Rhenish 

Massif of central Germany (Stribrny, 1987; Stribrny and 

others, 1988). These deposits occur in the Lower Carboniferous Variscan folded black shale series composed of 

black shales, black lydites, siliceous limestones, and clay 

shales. Commonly, these rocks host low-grade concentrations of stratabound sulfides, which are interpreted as 

sedimentary-exhalative depositions. Intraformational mobilizations and migrations of metals and their reprecipitation 

in physico-chemical traps led locally to minable ores. 

Additional metal concentrations were related to supergene 

processes (Stribrny and Urban, 1989). 

Manuscript approved for publication September 15, 1992. 1

Frankfurt University 

EXPERIMENT PARAMETERS 

Determination of Major and Trace Elements by 

X-ray Fluorescence Analysis 

An X-ray fluorescence (XRF) analytical program 

(called GEO, fig. 1) for the determination of 10 major and 

11 trace elements in rock samples has been developed using 

a glass bead 32 mm in diameter. Fusions of rock samples 

were made using a flux-to-sample ratio of 4:1. Calibration 

was established with 41 international geochemical reference 

standards. 

Sample Preparation 

For the sample preparation, a fusion method has been 

adopted. First, the rock powders were dried at 105°C for 3 

hours, and the flux (Merck A 12 Spectromelt = 66 percent 

Li2B40 7 +34-percent LiB02) was heated at 450°C for 3 

hours. Samples containing nonoxides as sulfides and 

organic carbon required further pretreatment prior to the 

fusion. For this pretreatment, 1.5 g NH4N03 was added to 

the mixture of 1 g rock powder and 4 g Spectromelt. 

Heating the Pt-Au crucible at 450°C for 1 hour disassociated 

the NH4N03 with subsequent oxidation of nonoxides. After 

oxidation, 20 mg NH4Br was added before proceeding with 

the fusions to avoid adhesion and erosion of the non wetting 

Pt-Au alloy crucible. 

The samples were then mixed with flux at a 4:1 

flux-to-sample ratio by weight. The mixtures were fused at 

1 ,200°C for 6 minutes in the Pt-Au crucible utilizing a RF 

induction heater with mechanical agitation (type: KontronRotomelt). At the end of fusion the crucible was inverted, 

and the melt was cast into a polished mold held at 500°C. 

The mold was then removed from the hot plate and cooled 

to room temperature. 

Determination of Trace Elements in USGS Devonian Ohio Shale SD0-1 81 
1'-J = 

-1 

::r 

(I) 

c: 

Vl 

C1 

Vl 

~ 

(I) 

1f 

(I) 

= r'l 

(I) 

V'l 

cu 

3 

"'C 

ii" 

c 

(I) 

~ 

Aj' = 

= 0 

::r 

cs· 

Vl 

::r 

cu 

;-

til 

c 

~ 

ORE ROCK 

LOOSE POWDER 

SPECIMEN 

5g SAMPLE 

39mm0 

MYLARFLM 

2,5p~, 

..... 

JAW CRUSHER 

<1cm0 

I 

J 

QUALITATIVE I SEMIQUANTITATIVE ANALYSIS ( RFA) 

53 ELEMENTS 

Ag, AI,As,Ba,BI,Br,Ca,Cd,Ce,CI,Co,Cr,Cs,Cu, F, Fe,Ga, 

Ge, Hf, H9,1, In, K, La, Mg,Mn,Mo,Na,Nb,Nd,NI,P, Pb,Pr,Rb 

S,Sb,Se,SI,Sm,Sn,Sr,Ta,Te,Th,TI,TI, U, V, W, Y, Zn, Z r, 

SEMI QUANT 

~ 

SHATTERBOX RING MILl 

(WC,AGATE) <50 ,urn 0 

MICRO MILL 

(\\C,AGATE,BC} 

DRYING ..... 105 ·c/3 hours 

WEIG~=~/- (CaaH7&N2Dr f··· ~-:;~;~;~: 

=:. .::::::= MIXER 

Pv'C·VIAL,AGATE BALL ~ .. 

ALU-CAP t1filll~l~lll~~~~~l~l~~~llmtJ 

~ 

HYDRAULIC PRESS 

2000kp/cm2 

PRESSED 

POWDER 

PELLET 

40mm0 

J 

PELLET 

DIE SET 

IDTtmmr~I%iH 

~ 

QUANTITATIVE ANALYSIS ( RFA) 

26 TRACE ELEMENTS 

Ba, Cd,Ce, Co, Cr, Cu, F, Ga, La, M o, 

Nb, Nd, Nl, Pb, Rb, S, Sc, Sm, Sr, Th, 

U, V, W, Y, Zn, Zr, 

TRACE 1+2 

Figure 1. Flow diagram of analytical sequence for the analysis of SD0-1. 

~ 

ROLL MIXER 

INDUCTION HEATER 

FUSE IN 

Pt/Au CRUCIBLE 

1200.C/6 min 

LOSS ON 

IGNITION 

1000 ·c11 hour 

WEIGHED SAMPLE 

1gSAMPLE 

+49 FLUX 

(U2BfJ7+li802) 

/"..... OXIDATION 

OF C,S,METALS 

+ 1,5g NH4N03 

hoor 

~ 

r--....,._ __ ..., CASTING INTO 

PREHEATED 

Pt/Au-MOULD 

-soo·c 

• 1 2 QUENCHING <500•c 

TEMPERING -400·C/2min 

COOLING - 20•c 

GLASS BEAD 

30mm0 

QUANTITATIVE ANALYSIS ( RFA) 

10 MAJOR- AND 12 TRACE ELEMENTS 

SI02, TI02, AI203, Fe203, MnO, MgO, 

CaO,Na20,K20,P203, 

Ba, Ce, Cr, La, Nb, N I, Rb, Sr, Th,V, Y, Z r, 

GEO 
Table 1. Instrument set-up (Rh-tube) of major and trace element analyses 

Element Line kV rnA Coll1 Crystal Dz Angle 

Al Ka 40 75 c PE FL 144.81 

Ba L~ 50 60 c LiF200 FL 79.22 

Ca Ka 40 50 F LiF200 FL 113.14 

Ce Ka 100 30 F LiF420 sc 22.81 

Cr Ka 50 60 F LiF220 FL 107.10 

Fe Ka 50 60 F LiF200 FL 57.53 

K Ka 50 60 F LiF200 FL 136.71 

La La 40 75 F LiF220 FL 138.91 

Mg Ka 40 75 c PX-1 FL 23.45 

Mn Ka 50 60 F LiF220 FL 95.19 

Na Ka 40 75 c PX-1 FL 28.29 

Nb Ka 100 30 F LiF220 sc 30.36 

Ni Ka 50 60 F LiF200 FL 48.67 

p Ka 40 75 c GE FL 141.00 

Rb Ka 100 30 F LiF220 sc 37.91 

Rh-comp. Ka 100 30 F LiF420 sc 41.89 

Si Ka 40 75 c PE FL 109.00 

Sr Ka 100 30 F LiF220 sc 35.77 

Ti Ka 50 60 F LiF200 FL 86.18 

v Ka 40 75 F LiF220 FL 123.18 

y Ka 100 30 F LiF220 sc 33.82 

Zr Ka 100 30 F LiF220 sc 32.01 

Ux6 100 30 F LiF220 sc 31.57 

Ux16 100 30 F LiF220 sc 38.64 

1

Coll: collimator C=550-micron spacing 

F= 150-rnicron spacing 2

0: detector FL =flow counter 

SC =scintillation counter 

Instrumentation 

Analyses were performed on an automated Philips 

PW 1404 sequential X-ray spectrometer controlled by a 

DEC micro-PDP11. The PW 1404 is equipped with a 

100-kV (3-kW) generator and a 12-position sample 

changer. A rhodium side-window tube and LiF420, 

LiF220, LiF200, GE, PE, and PX-1 analyzing crystals 

were used for the determinations (table 1). 

Correction of the quantitative measurement data to 

compensate for drift was done using a monitor sample. A 

polished shoshonitic volcanic rock was prepared as monitor 

sample, and eight major elements (Al, Ca, Fe, K, Mg, Na, 

Si, Ti) in the analytical program were corrected with 

drift -correction factors. 

Data Evaluation 

For matrix correction the new Philips calculation 

model was applied. The Philips model is a combination of 

correction models (Claisse-Quintin, 1967; de Jongh, 1973; 

Background Time (sec) Corrections 

+Offset -Offset Peak Bkg3 Bkg3 Lo4 I~ 

5.00 20 4 

1.34 120 60 

1.70 1.20 10 4 

.18 .30 150 150 X X 

1.30 60 30 X VKa 

1.00 10 4 X 

1.20 20 10 

1.40 200 100 

1.00 30 10 X 

.70 20 10 X 

4.00 30 10 X 

.90 150 150 YKax 

1.08 100 50 X X 

1.50 20 10 

Ux1 Ux 150 150 X X 

2.70 60 30 

2.00 20 4 

Ux1 Ux 150 150 X X 

1.00 20 10 X BaL~ 

2.50 60 30 X TiKa 

Ux1 Ux 150 150 X RbKa 

Ux1 Ux 150 150 X SrKa 

150 

150 

3

Bkg: background 4

Lo: line overlap corrections for line interferences VKI3, YKI3, 

BaLcx, TiKj3, SrKI3 5

Ir: internal ratio: RhKcx Compton 6

Background Correction 

Lucas-Tooth-Pyne, 1964; and Rasberry-Heinrich, 1974). 

The corrections may be based on count rates, concentrations, or combinations of both. The Philips model includes 

terms that can be calculated or entered during the regression 

analyses for spectral interferences, constant background, 

varying background, and line overlap correction factors. 

In the first step of regression analyses, theoretical 

alphas were used based on the fundamental parameter 

method (Criss and Birks, 1968; Shiraiwa and Fujino, 1966). 

The sample matrix, spectrometer geometry, and X-ray tube 

are taken into account in these theoretical alpha values. 

Regression analysis is considered to be more general and 

flexible for application to samples with wide concentration 

ranges. During regression analysis, the matrix correction 

factors (theoretical alphas) are, in part, recalculated. 

For several elements (Ni, Rb, Sr, Y, Zr, Nb, Ce) the 

"internal ratio" method has been applied (Leoni and Saitta, 

1977). This matrix correction is based on RhKa Compton 

scatter and corrects for absorption effects due to the major 

elements without the need to determine these elements 

(table 1). 

Determination of Trace Elements in USGS Devonian Ohio Shale SD0-1 83 
Loss on Ignition 

The rock powders were dried in an oven for 3 hours 

at 1 05°C. The dried rock powders were ignited for 1 hour at 

1 ,000°C in a muffle furnace using platinum crucible. Loss 

on ignition (LOI) was determined in duplicate by igniting 

1-g aliquots of sample powders. 

Determination of Gold by Graphite Furnace 

Atomic Absorption Spectrometry 

The determination of gold in geological samples 

requires its separation from the matrix. Instead of the 

frequently used 4-methyl-2-pentanon, the gold with palladium was extracted quantitatively by dibutyl sulfide in 

toluene, following a method described by Rubeska and 

others (1977). Besides Au and Pd, some Ag will also be 

extracted; whereas extraction of other elements can be 

neglected. A repeated treatment of geological samples with 

Table 2. The program parameters for the HGA-400 

Step 2 3 4 

Temperature °C 120 650 1900 2650 

Ramp time sec 10 10 0 1 

Hold time sec 20 30 5 3 

Gas flow mL/min 50 

aqua regia gives 99 percent recovery of Au. Gold contents 

up to 0.5 ~J.g/g should be detected by graphite furnace 

atomic absorption spectrometry (AAS), whereas higher 

contents demand flame AAS. Two portions of 10 g were 

taken from each bottle (bottles no. 0521 and no. 0756). The 

samples were dried at 11 0°C and then ashed for 2 hours 

each first at 480°C and then at 600°C, to oxidize all organic 

material, carbon, and sulfur. For total decomposition the 

samples were dissolved by HF and HCL04 and then treated 

with aqua regia. Gold was extracted from the solutions 

using 0.2M dibutyl sulfide in toluene. The measurements 

Table 3. X-ray fluorescence (XRF) determinations of major and trace elements in USGS Devonian Ohio Shale SD0-1 

SD0-1 SD0-1 SD0-1 SD0-1 

B. No. 0521 B. No. 0756 B. No. 0310 Mean 

Element X RMS1 RMS2 X RMS1 RMS2 X RMS1 RMS2 X RMS1 RMS2 

(wt%) (n=6) (%) (%rei.) (n=6) (%) (%rei.) (n=6) (%) (%rei.) (n=6) (%) (%rei.) 

Si02 49.82 0.063 0.13 48.19 0.057 0.12 48.61 0.055 0.11 48.88 0.714 1.46 

Ti02 .69 .001 .13 .67 .003 .49 .68 .004 .64 .68 .011 1.62 

Al20 3 12.54 .032 .25 12.15 .026 .22 12.51 .031 .25 12.40 .186 1.50 

Fe203TOT 9.31 .012 .13 8.95 .012 .13 9.12 .007 .08 9.12 .150 1.65 

MnO .039 .001 3.59 .035 .002 4.50 .037 .001 2.75 .037 .020 5.56 

MgO 1.53 .020 1.28 1.49 .008 .53 1.50 .019 1.28 1.51 .024 1.58 

CaO 1.07 .008 .78 1.03 .009 .92 1.04 .006 .58 1.05 .018 1.72 

Na20 .44 .014 3.23 .45 .014 3.15 .31 .018 5.89 .40 .067 16.79 

K20 3.25 .019 .58 3.13 .009 .29 3.17 .011 .36 3.17 .054 1.67 

P20s .11 .003 2.74 .11 .002 2.18 .11 .002 1.89 .11 .003 2.38 

LOI 19.77 21.75 20.98 20.83 

Total 98.57 97.96 98.07 98.19 

(f!.g/g) (f!.g/g) (f!.g/g) (f!.g/g) (f!.g/g) (f!.g/g) (f!.g/g) (f!.g/g) 

v 162 3 2.0 156 4 2.5 156 5 3.3 158 5 3.0 

Cr 63 3 4.5 65 6 8.7 66 5 7.0 65 5 6.8 

Ni 93 2 2.2 92 2 1.5 94 2 2.0 93 2 2.2 

Rb 135 1 .6 131 1 .5 136 1 .5 134 3 1.7 

Sr 84 1 1.2 81 1 1.2 54 1 1.8 73 14 18.6 

y 47 1 1.2 47 1 2.1 29 1 2.4 41 9 21.7 

Zr 175 1 .3 170 1 .3 167 1 .42 171 3 1.6 

Nb 13 1 4.9 13 1 3.4 13 1 1.4 13 1 4.7 

Ba 389 29 7.6 380 13 3.4 357 17 4.6 375 24 6.2 

La 37 10 26.0 34 4 9.8 37 6 14.9 36 7 18.0 

Ce 84 20 24.4 71 7 10.3 92 12 12.6 82 16 19.4 

1

RMS: root mean square (standard deviation) 2

RMS (% rel): percentage relative root mean square 

84 The USGS Reference Sample Devonian Ohio Shale SD0-1 
Table 4. Coulometric determinations of Ctov Ccarb' Corg' and S in USGS Devonian Ohio Shale SD0-1 

SD0-1 SD0-1 SD0-1 SD0-1 

B. No. 0521 B. No. 0756 B. No. 0310 Mean 

Element X RMS1 RMS2 X RMS1 RMS2 X RMS1 RMS2 X RMS1 RMS2 

(wt%) (n=6) (%) (%rei.) (n=6) (%) (%rei.) (n=6) (%) (%rei.) (n=6) (%) (%rei.) 

ctot 10.34 0.061 0.59 9.70 0.025 0.26 9.97 0.086 0.86 10.03 0.288 2.87 

ccarb .30 .013 4.33 .15 .004 2.67 .23 .004 1.74 .23 .066 28.70 

corg 10.04 .063 .63 9.55 .026 .27 9.74 .090 .92 9.80 .226 2.31 

(n=5) (n=4) (n=9) (n= 18) 

s 5.23 .071 1.36 5.10 .022 .43 5.18 .016 .31 5.17 .062 1.20 

1

RMS: root mean square (standard deviation) 2

RMS (% rel): percentage relative root mean square 

Table 5. Results for gold after fire assay preconcentration 

10-g run 

SD0-1 bottle no. 0521 

SD0-1 bottle no. 0756 

<0.005 

.01 

<.005 

.008 

were made using a Perkin Elmer HGA-400 graphite furnace 

in combination with a Zeiss FMD 4 atomic absorption 

spectrometer. The program parameters for the HGA, from 

Konopasek and others (1988), are given in table 2. 

Determination of CARBONtotal' 

CARBONcarbonate' CARBONorganic' and SULFUR 

by Coulometric Titration 

The carbon analyses were made following the method 

of Herrmann and Knake (1973). The sulfur determinations 

were done by adopting the method published by Lange and 

Brumsack (1977). For each run, portions of 100 g were 

taken from the bottles no. 0521, no. 0756, and no. 0310. To 

measure the total carbon content, 100 mg of each sample 

were ignited without additional reagents in an oxygen 

current at about 1 ,250°C. The carbonate carbon content was 

determined by dissolving 100 mg of each sample in orthophosphoric acid and measuring the evolved C02 . The 

organic carbon content was calculated by difference. 

To measure the sulfur content, 100 mg of each 

sample were mixed with 500 mg of V 20 5 and 500 mg of Fe 

and ignited at 1 ,380°C. The analyses were performed on a 

Strohlein Coulomat 702/SO/CS/E. The S02 released is 

absorbed in a Na2S04 solution (10 g Na2S04 in 200-mL 

doubly distilled water to which 2 mL of 30-percent H20 2 

had been added), lowering its pH. Again the pH is returned 

to its starting point by electrolysis. The amount of energy 

required is equivalent to the quantity of so2 absorbed. 

25-g run 

SD0-1 bottle no. 0521 

SD0-1 bottle no. 0756 

CONCLUSIONS 

AU(!J.g/g) 

0.004 

<.003 

Analytical data from all XRF determinations are 

presented in table 3, and analytical data for coulometric 

titrations to determine C and S are presented in table 4. 

Gold data in table 5 show inhomogeneous distribution of 

gold in 10-g samples. Because only a single repeat analysis 

from each bottle at 25-g sample sizes was possible, homogeneity could not be assessed based on the larger sample 

weight. These results also appear in the table. 

Precisions for MnO, Na20, and P20 5 within bottle 

are larger than expected based on past experience with the 

method. As a result, between-bottle analysis of variance 

shows no significant difference despite suspected inhomogeneity cited in Kane and others (1990). Similar inability to 

assess material in inhomogeneity because of large withinbottle imprecision affects the measurement for several trace 

elements (Cr, Sr, Y, Ba, La, and Ce). 

As figure 2 shows, the measured mean values (n= 18) 

presented in table 2 fit well within the range of confidence 

( ± standard deviations) of the recommended average values 

for SD0-1 published by Kane and others (1990). Mean 

values of Fe20 3 , K20, Nb, and Rb do not plot exactly 

within the confidence range shown; however, expansion of 

that range to ± two standard deviations does encompass 

those values (fig. 1); therefore, it can be concluded that the 

analytical methods (XRF, AAS, and coulometry) used are 

satisfactory, reliable tools for solving analytical problems 

related to the geochemistry of black shales. 

Determination of Trace Elements in USGS Devonian Ohio Shale SD0-1 85 
REFERENCES 

[%] 

Si02 

Al203 

Fe20 3 

CaO 

MgO 

NazO 

K20 

P20s 

Ti02 

MnO 

LOI 

s 

ctot 

corg 

[f.Lg/g] 

Au 

Ba 

Ce 

Cr 

La 

Nb 

Ni 

Rb 

Sr 

v 

y 

Zr 

+------------------Width of confidence interval-----------------~ 

Recommended 

values 

.. 48.65 ---------- 48.88 ---------49.28 ------------------

12.04 -----------===----------12.27 ---------12.40 

9.12 9.13 --------------------------- 9. 34 ---------===-- 1.00 -------------------- 1.05 1.05 ------------------

1.50 ---------- 1.51 --==--- 1.54 ------------------

.35 ------------==---------- .38 --------- .40 --

3.17 3. 29 --------------------------- 3. 35 ------------==-- .10 -------------------- .11 .11 ------------------

.68 0.68 ------------==--- . 71 ------------------

.037 .037 ----------------- .042 -----------------

20.8 20.8 --------------------21.7 ------------------

4.91 -==----- 5.17 --------- 5. 35 ------------------

9.51 ------------==---------- 9. 95 ---10.03 --------

9.23 --------------------------- 9.68 --- 9.80 --------

49.91 

12.50 

9.55 

1.10 

1.58 

.41 

3.41 

.12 

.74 

.047 

22.6 

5.79 

10.39 

10.13 

(0.002 ------------------------------------------- 0.0035 0.0035) 

359 --------- 375 -----------397 ----------------===- 435 

71 __________ -::::____________ 79 ------ 82 ------------ 87 

59 -------------------65---- 66 ------=------------- 74 

34 ---------- 36 -----=---- 39 ---------------------- 43 

10.2 -----------=------------ 11.4-------------------- 12.6 13.0 

90 ---------- 93------------100 ---------------------- 109 

122 -----------=------------126 ---------------------- 130 134 

64 -------------------7 3---- 7 5 ---------------------- 86 

139 ------------------158----160 ---------------------- 181 

34 -------------------41---- 41 ---------------------- 4 7 

141 -------------------=----165 -----171 ------------ 189 

Figure 2. Recommended average values for SD0-1 (central column) and their ranges of 

confidence(± standard deviation) (Kane and others, 1990) in comparison to the mean 

values as reported in tables 3 and 4 (italicized and underscored). 

C1aisse, Ferdinand, and Quintin, M., 1967, Generalization of the 

Lachance-Trail method for the correction of the matrix effect 

in X-ray fluorescence analysis: Canadian Spectroscopy, v. 

12, 129 p. 

Kikkert, J .N., 1981, Accurate geochemical analysis of samples of 

unknown composition, 31st Annual Denver X-ray Conference, 12 p. 

Konopasek Josef, Zereini, Fathi, and Urban, Hans, 1988, GoldBestimmung in geologischen Proben: Institute of Geochemistry, Frankfurt University, Open-File Report 1988-3, 1-11. 

Criss, J.W., and Birks, L.S., 1968, Calculation methods for 

fluorescent X-ray spectrometry-empirical coefficients vs. 

fundamental parameters: Analytical Chemistry, v. 46, 81 p. 

de Jongh, W.K., 1973, X-ray fluorescence analysis applying 

theoretical matrix corrections-stainless steel: X-ray Spectrometry, v. 2, p. 151. 

Herrmann, A.G., and Knake, Doris, 1973, Coulometrisches 

Verfahren zur Bestimmung von gesamt-, carbonat- und 

nichtcarbonat-Kohlenstoff in magmatischen, metamorphen 

und sedimentaren Gesteinen: Zeitschrift fiir Analytische 

Chemie, v. 266, p. 196-201. 

Kane, J.S., Arbogast, B.F., and Leventhal, J.S., 1990, Characterization of Devonian Ohio Shale SD0-1 as a USGS 

geochemical reference sample: Geostandards Newsletter, v. 

14, p. 169-196. 

86 The USGS Reference Sample Devonian Ohio Shale SD0-1 

Lange, J., and Brumsack, H.J., 1977, Total sulfur analysis in 

geological and biological materials by coulometric titration 

following combustion: Zeitschrift fiir Analytische Chemie, v. 

286, p. 361-366. 

Leoni, Leonardo, and Saitta, Maurizio, 1977, Matrix effect 

corrections by Ag Ko: Compton scattered ratiation in the 

analysis of rock samples for trace elements: X-ray Spectrometry, v. 6, p. 181. 

Lucas-Tooth, H.J., and Pyne, C., 1964, The accurate determination of major constituents by X-ray fluorescent analysis in the 

presence of large interelement effects: Advances in X-ray 

Analysis, v. 7, 523 p. 

Rasberry, S.D., and Heinrich, K.F.J., 1974, Calibration for 

interelement effects in X-ray fluorescence analysis: Analytical Chemistry, v. 46, 81 p. 
Rubeska, Ivan, Koreckova, J., and Weiss, Dalibor, 1977, The 

determination of gold and palladium in geological materials 

by atomic absorption after extraction with dibutyl sulfide: 

Atomic Absorption Newsletter, v. 16, 1-3. 

Shiraiwa, T., and Fujino, N., 1966, Japan Journal of Applied 

Physics, v. 5, p. 886. 

Stribmy, Bernhard, 1987, Die kupfererzlagerstatte Marsberg im 

rheinischen Schiefergebirge-Rtickblick und Stand der Forschung: Erzmetall, 40, 7/8, p. 423-427. 

Stribmy, Bernhard, and Urban, Hans, 1989, Lagerstiittenbildende, supergene umlagerungsprozesse in Schwarzschiefem: 

in Weisser, J.D. et al., eds.: Supergene Lagerstatten und ihre 

rohstoffwirtschaftliche Bedeutung: Erzmetall, 42, 7/8, p. 

348-350. 

Stribmy, Bernhard, Urban, Hans, and Webor, Herrbert, 1988, 

The lower Carboni Ferous Black Shale Formation, a possible 

source fo noble and base metal deposits in the Northeastern 

Rhenish Massif, FR Germany: Mineralogy and Petrology, 

39, p. 129-143. 

Determination of Trace Elements in USGS Devonian Ohio Shale SD0-1 87 

Chapter C 

Inductively Coupled Plasma Determination 

of Nine Rare Earth Elements in the 

USGS Devonian Ohio Shale SD0-1 

By IWAN ROELANDTS 

U.S. GEOLOGICAL SURVEY BULLETIN 2046 

THE USGS REFERENCE SAMPLE DEVONIAN OHIO SHALE SD0-1 

CONTENTS 

Abstract Cl 

Introduction Cl 

Experiment Parameters Cl 

Apparatus Cl 

ICP Equipment Cl 

Cation-Exchange Columns C2 

Reagents C2 

Cation-Exchange Resin C2 

Rare Earth Element Standard Solutions C2 

Chemicals C2 

Analytical Procedure C2 

Dissolution of the Samples C2 

Cation-Exchange Separation C2 

ICP-AES Measurements C2 

Results and Discussion C2 

Acknowledgments C5 

References C5 

FIGURES 

1. Wavelength scan of the Sm 359.260-nanometer line C3 

2. Chondrite-normalization pattern for the Devonian Ohio Shale SD0-1 C4 

TABLES 

1. Spectral interference correction coefficients C2 

2. Determination of nine rare earth elements in USGS Devonian Ohio Shale 

SD0-1 C3 

3. One-way analysis of variance C3 

4. Results obtained for USGS Devonian Ohio Shale SD0-1 in the present work 

compared with previous ICP data C4 

5. Determination of nine rare earth elements in USGS sedimentary reference 

samples C4 

Inductively Coupled Plasma Determination of 

Nine Rare Earth Elements in the USGS 

Devonian Ohio Shale SD0-1 

By I wan Roelandts 1 

Abstract 

The U.S. Geological Survey Devonian Ohio Shale 

SD0-1 has been analyzed for nine of the rare earth 

elements (REE) by inductively coupled argon plasma 

atomic emission spectrometry (ICP-AES). Triplicate portions from two bottles of the material were analyzed in 

random order to estimate analytical precision and test for 

homogeneity. The precision, based on the samples analyzed, is generally better than 1 percent. The one-way 

analysis of variance was used with our lCP determinations; no evidence for differences in REE concentrations 

between these two randomly selected bottles was 

observed. 

INTRODUCTION 

Nine of the rare earth elements (REE) in the U.S. 

Geological Survey (USGS) Devonian Ohio Shale SD0-1 

were determined by inductively coupled plasma atomic 

emission spectrometry (ICP-AES) following cationexchange separation. Two bottles randomly selected from 

the stock were received and three separate portions from 

each bottle were analyzed to provide a one-way experimental design using the two bottles as the single variable of 

classification. The six portions were analyzed in random 

order. 

The REE have been found to be extremely useful in 

several studies of sedimentary processes (weathering, transport, and diagenesis). Very few years ago, instrumental 

neutron activation analysis (INAA) and isotope dilution 

mass spectrometry (IDMS) were the only sensitive and 

accurate techniques in use for geochemical REE analysis. 

ICP-AES is rapidly becoming an established analytical 

method for the determination of REE, especially when large 

numbers of samples of common silicate rocks must be 

analyzed. This technique has several advantages, the prinManuscript approved for publication September 15, 1992. 1

University of Liege 

cipal of which are low detection limits, good precision and 

accuracy, low sample matrix effects, speed of analysis, and 

wide linear dynamic concentration range. 

ICP spectra of rock samples are not simple; a very 

large number of emission lines are present. To avoid 

interference from other elements and thereby improve 

accuracy and detection limits, some workers chemically 

separated the REE as a group from the rock matrix, in most 

cases by an ion-exchange procedure (for example, Walsh 

and others, 1981; Brenner and others, 1981, 1984; Crock 

and Lichte, 1982; Bolton and others, 1983; Yoshida and 

others, 1983; Crock and others, 1984, 1986; Aulis and 

others, 1985; Jarvis and Jarvis, 1985, 1988; Roelandts and 

Michel, 1986; Roelandts, 1988a; Roelandts, 1990; Govindaraju and Mevelle, 1987; Zachman, 1988; Sulcek and 

others, 1989; Watkins and Nolan, 1990). 

In this work a separation of the REE from the other 

constituents after an acid decomposition of the sample was 

achieved using the strong acid-type resin Dowex 50WX8. 

The REE were first held quantitatively on the cationic resin 

during the initial washing with 1. 15M hydrochloric acid to 

remove unwanted elements and then desorbed using 8M 

nitric acid as an eluent. The experimental conditions of this 

separation procedure have been previously determined 

(Roelandts, unpub. data, 1975). 

EXPERIMENT PARAMETERS 

Apparatus 

ICP Equipment 

A Bausch and Lomb model 3510 sequential ICP 

spectrometer (Applied Research Laboratories) operated at 

1.2 incident kW was used for this study. A DEC PDP-11 

computer controlled all instrument functions. The plasma 

gas-flow and the coolant gas-flow rates were 0.8 and 12.0 

L/min, respectively. A concentric Meinhard type nebulizer 

was employed, and the sample solution uptake was fixed 

at 3 mL/min. The observation height was 15 mm above 

the load coil. Further details on the instrumentation are 

Inductively Coupled Plasma Determination of Nine Rare Earth Elements in the USGS Devonian Ohio Shale SD0-1 C1 
available elsewhere (Roelandts and Michel, 1986; Roelandts, 1988a). 

Cation-Exchange Columns 

Borosilicate glass tubes of 10-mm internal diameter 

filled with Dow ex 50X8 cation-exchange resin ( 6-g dry 

weight) were used as columns. The settled resin height in 

the column was adjusted to 200 mm. Before starting the 

separation, the columns were equilibrated by passing 50 mL 

of 1. 75M hydrochloric acid through them. 

Reagents 

Cation-Exchange Resin 

The resin used was the Dowex 50X8 sulphonated 

cation exchanger (hydrogen form, 100 to 200 mesh) supplied by Fluka Co., Buchs, Switzerland. Before use, the 

fine particles were removed by several decantations. 

Rare Earth Elements Standard Solutions 

Individual REE solutions (1 ,000 J.Lg/mL) were prepared by dissolving high purity (99. 9 percent) REE oxides 

(Rare-Earth Products Ltd., London, U.K.) in hot nitric 

acid. Before weighing, the oxides were heated at 95°C. 

The single-element solutions were prepared by appropriate dilution of the stock solutions. All solutions were 

stored in polypropylene bottles having a total nitric acid 

content of 5 percent by volume. 

Chemicals 

All the acids used were analytical-reagent grade. 

Analytical Procedure 

Dissolution of the Samples 

Samples 1-g each were digested on a water-bath using 

hydrofluoric-nitric acid attack and evaporated to dryness. 

The salts were dissolved in concentrated hydrochloric acid 

by heating. The solutions were again evaporated to dryness. 

The HCl digestion was repeated at least twice. Finally, the 

residues were dissolved in 1. 75M HCl. 

Cation-Exchange Separation 

The 1. 75M HCl sample solution was passed through 

the preequilibrated resin column. After the elution of iron, 

calcium, and other unwanted matrix elements with 100 mL 

of 1.75M HCl, the REE adsorbed on the column were 

washed out with 75 mL 8M HN03 • All separations were 

done at an eluent flow rate of about 1 mL/min. Six separate 

exchange experiments were performed simultaneously. 

The REE eluate was then evaporated to dryness, 

dissolved in 5-percent (VIV) nitric acid, and diluted to 25 

C2 The USGS Reference Sample Devonian Ohio Shale SD0-1 

Table 1. Spectral interference correction coefficients 

Wavelength 

Element (in nanometers) 

La 

Ce 

Nd 

Sm 

Eu 

Gd 

Dy 

Yb 

Lu 

398.852 

418.660 

430.358 

359.260 

381.967 

342.247 

353.170 

328.937 

261.542 

Interfering rare earth elements 

and correction coefficients 

Nd (0.0372) 

Nd (0.0040) 

Ce (0.0037) 

Nd (0.0012) 

Gd (0.0313) 

mL. This solution was stored in a polypropylene bottle until 

the ICP-AES measurements were carried out. 

ICP-AES Measurements 

For each sample solution nebulized into the plasma, a 

stabilization time was set at 30-s ("preflush time") and 

followed by three 1-s signal integrations; the sample 

intensities were calculated as the arithmetic mean of these 

three readings. External calibration was made using singleelement solutions of REE (in 5-percent (VIV) nitric acid). A 

5-percent (VIV) nitric acid solution was used to determine 

the true background under the peak. All intensities were 

corrected for background so obtained. 

After the cation-exchange separation procedure, the 

only important spectral interferences that remained were 

those caused by overlap from other REE peaks. The REE 

analytical lines selected in this work are listed in table 1. 

The choice is a compromise between signal intensity and 

relative freedom from spectral interferences. Spectral profiles of these lines and correction coefficients for mutual 

REE interferences have been previously reported (Roelandts and Michel, 1986). They are largely dependent on 

the resolution of the spectrometer and may vary from 

instrument to instrument. A wavelength scan 0.1 nanometer 

(nm) on each side of the Sm emission line at 359.260 nm 

( 10 J.Lg/mL Sm; 100 J.Lg/mL for other REE) is illustrated in 

figure 1. Overlap corrections introduced in this study are 

indicated in table 1. For example, a sample that contains 1 

J.Lg/g Nd generates the equivalent of 0.0372 J.Lg/g Sm; 

therefore, the contributions from Nd to Sm will be estimated by multiplying the Nd concentrations by 0.0372 and 

subtracting this product from the total measured Sm content. 

RESULTS AND DISCUSSION 

Three portions from the two bottles of SD0-1 were 

analyzed in random order for nine REE (La, Ce, Nd, Sm, 

Eu, Gd, Dy, Yb, and Lu). The experimental results of the 

individual samples (average of three measurements on the 
Table 2. Determination of nine rare earth elements in USGS Devonian Ohio Shale 

SD0-1 

[All concentrations in J.,Lg/g] 

Bottle 0189 

Determination 

Element A B c 

La 36.2 35.6 35.6 

Ce 76.9 75.3 75.3 

Nd 37.9 38.0 38.7 

Sm 7.7 7.6 7.5 

Eu 1.64 1.66 1.65 

Gd 7.8 7.6 7.8 

Dy 6.1 6.0 6.0 

Yb 3.05 2.99 3.00 

Lu .45 .44 .44 

solution) are presented in table 2, including the mean of the 

six separate analyses. Based on these analyses, precision is 

estimated to be better than 1 percent. 

The one-way analysis of variance was used with the 

ICP data to determine if the bottles are homogeneous with 

respect to REE content. Table 3 summarizes the calculations and the conclusions from the analysis of variance. The 

F ratio calculated for REE in no case exceeds the allowable 

I 

I 

I 

Sm 

359.260 

Dy\ · Ho 

I;"\ 

r \ 

;. \ 

I \ \ 

'k \ \ 

' ' 

Nd 

f', 

I I 

I I I I 

I I 

I I 

I 

I 

Gd 

y 

1\ 

,, 

WAVELENGTH, IN NANOMETERS 

Figure 1. Wavelength scan of the Sm 359.260-

nanometer line (10 J.Lg/ml Sm; 100 J.Lg/ml for other 

rare earth elements). 

Bottle 0717 

Determination 

A B c Mean 

36.0 35.9 36.0 35.9 

77.6 76.7 74.9 76.1 

38.5 38.1 38.3 38.3 

7.7 7.6 7.6 7.6 

1.65 1.67 1.69 1.66 

7.8 7.9 7.9 7.8 

6.1 6.1 6.1 6.1 

3.04 3.09 3.08 3.04 

.45 .45 .47 .45 

value F cCO. 95)(1 ,4) = 7. 7086 as shown in the F tables. 

Therefore, the statistical analysis demonstrated that SD0-1 

may be considered homogeneous for the elements specified 

at the 95-percent confidence level. Because of the random 

selection of the bottles for the experiment, this conclusion 

may be extrapolated to the entire lot of bottles. 

In table 4, the average REE concentrations obtained 

in the present work (bottle 0717) are compared with results 

for one analysis of this sample previously undertaken in our 

laboratory about 18 months ago. The agreement between 

these two sets of data is judged to be excellent and reflects 

the long-term reproducibility that can be achieved using the 

outlined method. Additionally, from this table it can be seen 

that our determinations compare favorably with the 

ICP-AES values reported by Crock and others (1986) and 

with the final recommended concentrations (Kane and 

others, 1990). 

The accuracy of our ICP-AES method has been 

established by performing analyses on more that 40 different international geochemical reference materials (Roelandts and Michel, 1986; Roelandts, 1987, 1988a, 1988b, 

1989) and through participation in a series of collaborative 

Table 3. One-way analysis of variance 

[d.f., degree of freedom; NS. not significant] 

Mean squares 

Element d.f.=1 d.f.=4 F-ratio Conclusion 

La 0.04167 0.06167 0.6757 NS 

Ce .48167 1.37167 .3512 NS 

Nd .01500 .11500 .1304 NS 

Sm .00167 .00667 .2500 NS 

Eu .00060 .00025 2.4000 NS 

Gd .01000 .02000 .5000 NS 

Dy .00667 .00167 4.0000 NS 

Yb .00482 .00087 5.5577 NS 

Lu .00027 .00008 3.2000 NS 

Inductively Coupled Plasma Determination of Nine Rare Earth Elements in the USGS Devonian Ohio Shale SD0-1 C3 
Table 4. Results obtained for USGS Devonian Ohio Shale SD0-1 in the present work 

compared with previous ICP data 

[All concentrations in J.Lg/g; ICP, inductively coupled plasma] 

Element This work1 Previous work1

'

2 

La 

Ce 

Nd 

Sm 

Eu 

Gd 

Dy 

Yb 

Lu 

36.0 

76.4 

38.3 

7.6 

1.67 

7.8 

6.1 

3.07 

.46 

1 Bottle 0717 2

Roelandts, 1988b 3

Kane, table 1, p. 2, this volume 

35.9 

76.2 

38.2 

7.6 

1.68 

7.8 

5.9 

3.04 

.45 

*recommended (all others are compilation averages) 

Crock and others, 1986 Average3 

35.6 *38.5±4.4 

71.8 *79.3±7.8 

36.3 36.6±3.3 

7.6 7.7±0.81 

1.65 1.6±0.22 

7.8 7.4± 1.9 

6.1 *6.0±0.65 

3.11 *3.4±0.46 

.44 .54±0.14 

Table 5. Determination of nine rare earth elements in USGS sedimentary reference samples 

[All concentrations in j.Lg/g; ICP, inductively coupled plasma] 

MAG-1 SC0-1 SDC-1 SGR-1 

Marine mud1 Code Shale2 Mica schise Green River Shale 

Consensus 

Element ICP4

'

5 value6 

La 

Ce 

Nd 

Sm 

Eu 

Gd 

Dy 

Yb 

Lu 

(/) 

w 

~ 

a: 

0 

z 

0 

I 

u 

~ 

w 

w 

~ 

I 

0 

0 

(/) 

~ 

w 

w 

a: 

42.6 43±4 

90.2 88±9 

38.3 38±5 

7.4 7.5±0.6 

1.48 1.55±0.14 

5.8 5.8±0.7 

4.8 5.2±0.3 

2.82 2.6±0.27 

.39 .40±0.04 

1

Manheim, and others, 1976 2

Schultz, and others, 1976 3

Flanagan and Carroll, 1976 

100 

50 

La Ce 

57 

Nd Sm Eu Gd Dy 

ATOMIC NUMBER 

lcp4·s 

29.1 

59.0 

26.0 

5.5 

1.12 

4.0 

3.7 

2.28 

.33 

Consensus Consensus Consensus 

value6 lcp4·s value6 lcp4·s value6 

29.5±1.1 42.6 42±3 18.6 20.3± 1.8 

62±6 95.2 93±7 33.8 36±4 

26±2 41.2 40±4 14.8 15.5±1.7 

5.3±0.3 8.3 8.2±0.5 2.1 2.7±0.3 

1.19±0.12 1.67 1.71 ±0.12 .41 .56±0.09 

4.6±0.7 6.7 7.2±0.4 2.21 2.0±0.4 

4.2±0.5 6.4 6.7±0.9 1.82 1.9±0.3 

2.27±0.24 3.9 4.0±0.7 .96 .94±0.16 

.338±0.033 .50 .53±0.11 .17 .14±0.03 

Yb Lu 

71 

4

Roelandts, 1987 5

Roelandts, 1988a 6

Gladney and Roelandts, 1988 

studies. Good agreement between our ICP determinations 

and the preferred values for these reference materials is 

observed in most cases. Table 5 contains results of nine 

REE in USGS sedimentary reference samples. Comparison 

of our ICP values with the consensus values calculated by 

Gladney and Roelandts (1988) indicates an accuracy of ±4 

percent. The absence of any serious systematic bias in our 

REE determinations is also evident and shows the validity 

of the analytical procedure. 

Figure 2. Chondrite-normalization pattern for the Devonian Ohio Shale SD0-1. 

The chondrite normalized concentrations for SD0-1 

are plotted against the atomic number in figure 2 using the 

chondrite values reported by Laul and Rancitelli ( 1977). 

This procedure offers a quick evaluation of the quality of 

data for REE abundances. A smooth curve that is widely 

accepted as a quality criterion for REE analysis can be 

observed in our case. 

C4 The USGS Reference Sample Devonian Ohio Shale SD0-1 
ACKNOWLEDGMENTS 

We are grateful to V. Miocque and G. Delhaze for 

their assistance. The ICP equipment used for this study was 

purchased with funds from the Belgian "Fonds de la 

Recherche Fondamentale Collective," under contract no. 

9.4569.83. 

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selected rare-earth elements in geological materials using 

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377-387. 

Bolton, Alexander, Hwang, Jack, and Vander Voet, Anthony, 

1983, The determination of scandium, yttrium and selected 

rare earth elements in geological materials by inductively 

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Brenner, LB., Jones, E.A., Watson, A.E., and Steele, T.W., 

1984, The application of a N2-Ar medium-power ICP and 

cation-exchange chromatography for the spectrometric determination of the rare-earth elements in geological materials: 

Chemical Geology, v. 45, p, 135-148. 

Brenner, LB., Watson, A.E., Steele, T.W., Jones, E.A., and 

Goncalves, M., 1981, Application of an argon-nitrogen 

inductively-coupled radio frequency plasma (ICP) to the 

analysis of geochemical and related materials for their rareearth contents: Spectrochimica Acta, v. 36B, p. 785-797. 

Crock, J.G., and Lichte, F.E., 1982, Determination of rare-earth 

elements in geological materials by inductively coupled argon 

plasma/atomic emission spectrometry: Analytical Chemistry, 

v. 54, p. 1329-1332. 

Crock, J.G., Lichte, F.E., Riddle, G.O., and Beech, C.L., 1986, 

Separation and preconcentration of the rare-earth elements 

and yttrium from geological materials by ion-exchange and 

sequential acid elution: Talanta, v. 33, p. 601-606. 

Crock, J.G., Lichte, F.E., and Wildemann, T.R., 1984, The 

group separation of the rare-earth elements and yttrium from 

geologic materials by cation-exchange chromatography: 

Chemical Geology, v. 45, p. 149-163. 

Flanagan, F.J., and Carroll, G.V., 1976, Mica-schist, SDC-1 

from Rock Creek Park, Washington, D.C.: U.S. Geological 

Survey Professional Paper 840, p. 29-32. 

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elemental concentration data for USGS BHV0-1, MAG-1, 

QL0-1, RGM-1, SCo-1, SDC-1, SGR-1, and STM-1: 

Geostandards Newsletter, v. 12, p. 253-362. 

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coupled plasma atomic emission spectrometry rock analysis. 

Application to the determination of rare-earth elements: 

Journal of Analytical Atomic Spectrometry, v. 2, p. 

615-621. 

Jarvis, Ian, and Jarvis, K.E., 1985, Rare-earth element geochemistry of standard sediments-a study using inductively coupled plasma spectrometry: Chemical Geology, v. 53, p. 

335-344. 

---1988, Determination of the rare-earth elements and yttrium 

in 37 international silicate reference materials by inductively 

coupled plasma-atomic spectrometry: Geostandards Newsletter, v.12, p. 1-12. 

Kane, J.S., Arbogast, Belinda, and Leventhal, Joel, 1990, Characterization of Devonian Ohio Shale SD0-1 as a USGS 

geochemical reference sample: Geostandards Newsletter, v. 

14, p. 169-196. 

Laul, J.C., and Rancitelli, L.A., 1977, Multielement analysis by 

sequential instrumental and radiochemical neutron activation: 

Journal of Radioanalytical Chemistry, v. 38, p. 461-475. 

Manheim, F.T., Hathaway, J.C., Flanagan, F.J., and Fletcher, 

J.D., 1976, Marine Mud, MAG-1, from the Gulf of 

Maine: U.S. Geological Survey Professional Paper 840, 

p. 25-28. 

Roelandts, I wan, 1987, Determination of nine rare-earth elements 

in eight USGS reference samples and in the ANRT glauconite, GL-0, by sequential inductively coupled argon plasma 

spectrometry: Geostandards Newsletter, v. 11, p. 49-74. 

---1988a, Comparison of inductively coupled plasma and 

neutron activation analysis for precise and accurate determination of nine rare-earth elements in geological materials: 

Chemical Geology 67, p. 171-180. 

---1988b, Application of inductively coupled plasma spectrometry to the determination of nine rare earth elements in 

nine new U.S. Geological Survey reference samples: Atomic 

Spectroscopy, v. 9, p. 49-54. 

---1989, Inductively coupled plasma determination of nine 

rare-earth elements in nine Geological Survey of Japan rock 

reference samples: ICP Information Newsletter, v. 15, p. 

309-310. 

---1990, Inductively coupled plasma determination of nine 

rare-earth elements in sixty international geochemical reference samples: Geostandards Newsletter, v. 14, p. 137-147. 

Roelandts, Iwan, and Michel, G., 1986, Sequential inductively 

coupled plasma determination of some rare-earth elements in 

five French geostandards: Geostandards Newsletter, v. 10, p. 

135-154. 

Schultz, L.G., Tourtelot, H.A., and Flanagan, F.J., 1976, Cody 

Shale SCo-1, from Natrona County, Wyoming: U.S. Geological Survey Professional Paper 840, p. 21-23. 

Sulcek, Zdenek, Rubeska, Ivan, Sixta, Vaclav, and Paukert, 

Tomas, 1989, Determination of rare-earth elements and 

yttrium in rocks using the Plasma II ICP emission spectrometer: Atomic Spectroscopy, v. 10, p. 4-9. 

Walsh, J.N., Buckley, F., and Barker, J., 1981, The simultaneous 

determination of rare-earth elements in rocks using inductively coupled plasma source spectrometry: Chemical Geology, v. 33, p. 141-153. 

Watkins, P.J., and Nolan, J., 1990, Determination of rare-earth 

elements, scadium, yttrium and hafnium in 32 geochemical 

reference materials using inductively coupled plasma atomic 

emission spectrometry: Geostandards Newsletter, v. 14, p. 

11-20. 

Inductively Coupled Plasma Determination of Nine Rare Earth Elements in the USGS Devonian Ohio Shale SD0-1 C5 
Yoshida, K., Fuwa, K., and Haraguchi, H., 1983, Determination 

of 15 rare-earth elements by liquid chromatography with 

inductively coupled plasma atomic emission spectrometric 

detection: Chemical Letter, p. 1879-1882. 

C6 The USGS Reference Sample Devonian Ohio Shale SD0-1 

Zachmann, D.W., 1988, Matrix effects in the separation of rare 

earth elements, scandium, and yttrium and their determination by inductively coupled plasma emission spectrometry: 

Analytical Chemistry, v. 60, p. 420-427. 
Chapter D 

Instrumental Neutron Activation Analysis of 

Devonian Ohio Shale SD0-1 

By GREGORY A. WANDLESS 

U.S. GEOLOGICAL SURVEY BULLETIN 2046 

THE USGS REFERENCE SAMPLE DEVONIAN OHIO SHALE SD0-1 

CONTENTS 

Abstract Dl 

Introduction Dl 

Experiment Parameters Dl 

Results Dl 

Discussion D2 

Acknowledgments D4 

References D4 

FIGURES 

1. The Lu/U(Np) doublet prior to interactive fitting D4 

2. The Lu/U(Np) doublet after interactive fitting D4 

3. Graph showing chondrite normalized rare-earth plot of SD0-1 D4 

TABLES 

1. Instrumental neutron activation analysis results for USGS geochemical reference 

sample SD0-1 D2 

2. Analysis of variance results for INAA of SD0-1 D3 

3. Fission product correction factors D3 

Instrumental Neutron Activation Analysis of 

Devonian Ohio Shale SD0-1 

By Gregory A. Wandless 

Abstract 

The U.S. Geological Survey geochemical reference 

sample Devonian Ohio Shale SD0-1 was analyzed by 

instrumental neutron activation analysis. The relatively 

high uranium concentration in SD0-1 caused several 

isotopic and spectral interferences that had to be 

resolved. Special data processing techniques were applied 

to the assay of lutetium to remove spectral interferences 

from uranium, and significant corrections had to be 

applied to several elements for fission product interferences. A correction for the ruthenium fission product 

interference has been made to barium since the publication of the original SD0-1 compilation, resulting in a 

significant improvement in accuracy. Four replicates from 

two randomly selected bottles were analyzed; and the 

precision was estimated to be 5 percent or better for a 

majority of elements, and the accuracy was demonstrated 

by no rejection of data in the determination of ''recommended values." Analysis of variance shows no significant 

variation between bottles. 

INTRODUCTION 

A discussion of the purpose for collecting SD0-1 , 

sample description and preparation, and the analytical 

program have already been presented (Kane and others, 

1990). Applying instrumental neutron activation analysis 

(INAA) to the analysis of SD0-1 provides an efficient 

means for characterization because the method can provide 

precise data for approximately 30 major, minor, and trace 

elements in a single sample aliquot without chemical 

treatment. The underlying principles and the application of 

INAA to geologic samples have been described numerous 

times (Gordon and others, 1968; Hertogen and Gijbels, 

1971; Baedecker and others, 1977; Jacobs and others, 1977; 

Laul, 1979; Baedecker and McKown, 1987). The most 

significant problems associated with the analysis of SD0-1 

will be discussed in detail. 

Manuscript approved for publication September 15, 1992. 

EXPERIMENT PARAMETERS 

The samples of SD0-1 as received for analysis 

needed no further treatment for activation analysis. Four 

aliquots of SD0-1 from each of two bottles, two multielement standards, a standard for calcium and titanium, and 

the U.S. Geological Survey (USGS) geochemical reference 

sample SGR-1, all weighing approximately 0.5 g, were 

weighed into 2/5-dram polyethylene vials. The vials were 

heat sealed, placed in a polyethylene bag, and packed into 

an aluminum can for irradiation. 

Samples and standards were irradiated simultaneously for 8 hours in the A-2 position of the Texas A&M 

reactor facility, providing a neutron flux of 2X 1012 neutrons em - 2

s -t. After irradiation, the samples were returned 

after decaying for 7 days. The vials were then unpacked, 

washed externally with water and alcohol, and placed in 

clean 2-dram polyethylene vials for counting. 

Samples and standards were counted on coaxial, 

high-purity germanium (HPGe) and low-energy photon 

detectors (LEPD) 7 days after irradiation for 1 hour each, 

after 14 days on a HPGe for 1 hour, and again on the HPGe 

and LEPD after 2 months for 2 hours. Gamma-ray spectra 

were acquired on a Nuclear Data 6700 multichannel analyzer and transferred to a VAX 111780 for data reduction. 

Spectra were analyzed using the SPECTRA program (Raedecker and Grossman, 1989). 

RESULTS 

Results for the eight replicate analyses of SD0-1 are 

given in table 1. Means and standard deviations were 

computed assuming no between-bottle variance. The precision for the majority of elements is 5 percent or better, and 

only two (Ti and Zr) have a coefficient of variation of 

greater than 10 percent. With regard to accuracy, it is noted 

that only data for barium were rejected during the initial 

determination of "recommended values" or averages for the 

SD0-1 standard. Since the initial analysis, corrections for 

fission-product interference on barium have been determined and have improved the accuracy of the barium data 

such that those results can now be included in the derivation 

of recommended values. To evaluate sample homogeneity 

Instrumental Neutron Activation Analysis of Devonian Ohio Shale SD0-1 01 
Table 1. Instrumental neutron activation analysis results for USGS geochemical reference sample SD0-1 

Bottle 699 Bottle 761 

Standard 

Replicate 1 Replicate 2 Replicate 3 Replicate 4 Replicate 1 Replicate 2 Replicate 3 Replicate 4 Mean deviation 

Na (wt. %) 

K 

Ca 

Ti 

Fe 

Sc (JJ.g/g) 

Cr 

Co 

Ni 

Zn 

As 

Se 

Rb 

Sr 

Zr 

Mo 

Sb 

Cs 

Ba 

La 

Ce 

Nd 

Sm 

Eu 

Tb 

Yb 

Lu 

Hf 

Ta 

Th 

u 

0.266 

2.76 

<12 

<.7 

6.56 

12.4 

62.7 

45.0 

95 

62 

63.0 

7.3 

127 

<230 

124 

123 

4.66 

6.41 

404 

33.1 

69.7 

31 

7.56 

1.46 

1.13 

3.43 

.48 

4.43 

1.10 

9.65 

40.4 

0.269 

2.71 

<12 

<.6 

6.59 

12.6 

64 

45.3 

101 

65 

63.2 

6.3 

133 

138 

<260 

126 

4.66 

6.46 

383 

33.6 

72.2 

33 

7.73 

1.51 

1.17 

3.42 

.49 

4.46 

1.08 

9.91 

41.2 

0.269 

2.65 

<11 

.82 

6.53 

12.3 

63 

44.2 

83 

61 

61.9 

<5 

129 

140 

100 

127 

4.62 

6.39 

409 

33.2 

69.5 

31 

7.68 

1.44 

1.20 

3.38 

.48 

4.38 

1.07 

9.70 

41.3 

0.269 

2.71 

<11 

<.9 

6.56 

12.4 

64.5 

44.6 

92 

61 

63.4 

6.6 

129 

140 

140 

129 

4.52 

6.56 

397 

33.6 

70.9 

33 

7.78 

1.48 

1.17 

3.47 

.50 

4.37 

1.09 

9.85 

40.8 

for the elements determined by INAA, an analysis of 

variance was performed on the data, and the F-statistic was 

tabulated in table 2. Since the critical F-value for the given 

degrees of freedom was not exceeded in any case, the 

hypothesis that there is no significant variation between 

bottles is accepted. 

DISCUSSION 

Baedecker and McKown (1987) give a detailed 

description of the factors that can affect the precision and 

accuracy of INAA; and for the majority of the trace 

elements determined in SD0-1, those factors were 

accounted for or insignificant during the analysis. For 

example, errors due to poor counting statistics were unimportant because of the relatively high count rates obtained 

during the analysis of SD0-1. However, the relatively high 

concentration of uranium (40 JJ.g/g) introduced two forms of 

interferences that required evaluation for their effects on the 

analysis of SD0-1. 

02 The USGS Reference Sample Devonian Ohio Shale SD0-1 

0.264 

2.67 

<14 

.53 

6.40 

12.1 

62.5 

43.7 

86 

60 

62.7 

<5 

125 

158 

102 

125 

4.37 

6.29 

394 

33.0 

68.6 

32 

7.60 

1.44 

1.13 

3.27 

.47 

4.27 

1.06 

9.60 

40.4 

0.272 

2.82 

<14 

<.6 

6.50 

12.3 

64.3 

44.3 

86 

58 

62.7 

<8 

130 

140 

84 

126 

4.48 

6.44 

413 

33.1 

70.4 

33 

7.60 

1.47 

1.10 

3.25 

.47 

4.39 

.99 

9.71 

40.4 

0.269 

2.66 

<11 

.62 

6.58 

12.4 

64.6 

45.1 

100 

58 

62.6 

<8 

125 

130 

160 

124 

4.68 

6.42 

423 

33.1 

70.8 

33 

7.60 

1.47 

1.18 

3.49 

.47 

4.38 

1.07 

9.86 

40.5 

0.269 

2.68 

<11 

<.6 

6.61 

12.4 

63.5 

44.9 

91 

63 

62.4 

<5 

126 

140 

<130 

127 

4.68 

6.38 

406 

33.4 

70.6 

33 

7.69 

1.46 

1.13 

3.40 

.48 

4.37 

1.09 

9.85 

41.0 

0.268 

2.71 

.66 

6.54 

12.4 

63.6 

44.6 

92 

61 

62.7 

6.7 

128 

141 

118 

126 

4.58 

6.42 

403 

33.3 

70.3 

32 

7.66 

1.47 

1.15 

3.39 

.48 

4.38 

1.07 

9.77 

40.8 

0.0024 

.050 

.150 

.067 

.140 

.83 

.54 

6.6 

2.36 

.47 

.51 

2.80 

8.4 

28.4 

1.90 

.115 

.070 

12.3 

.240 

1.08 

.80 

.070 

.0220 

.030 

.080 

.0110 

.050 

.030 

.115 

.38 

During neutron irradiation, 235U and 238U undergo 

fission, producing a host of daughter products called fission 

products. Some of these fission products are identical to the 

indicator radionuclides produced by the neutron irradiation 

of certain trace elements in SD0-1 (isotopic interference). 

Others have gamma-ray lines close to the lines of interest 

(spectral interferences). Failing to correct for these interferences will produce anomalous results for some elements. 

There are seven trace elements determined by INAA that 

can have significant interferences from uranium-fission 

products: Ba, Mo, Zr, La, Ce, Nd, and Sm. Corrections for 

the isotopic interference from fission products can be 

determined by theoretical calculations or by irradiating a 

known quantity of uranium and measuring the quantity of 

those elements produced. The analytical data can then be 

corrected based on a determination of the concentration of 

uranium in the sample using the 277 ke V gamma-ray from 239Np. Table 3 gives the correction factors used in this study 

that are consistent with the recent review of the available 

literature of fission-product corrections used in activation 

analysis (Landsberger, 1989). 
Table 2. Analysis of variance results for INAA of SD0-1. 

[F--<:ritical (95%) for Sr 6.6079, Zr 7.7087, all others 5.9874; 

insufficient data] 

Element 

Na ............................................... . 

K ................................................ . 

Ca ............................................... . 

Sc ................................................ . 

Ti ................................................ . 

Cr ................................................ . 

Fe ................................................ . 

Co ............................................... . 

Ni ................................................ . 

Zn ............................................... . 

As ............................................... . 

Se ................................................ . 

Rb ............................................... . 

Sr ................................................ . 

Zr ................................................ . 

Mo ............................................... . 

Sb ............................................... . 

Cs ............................................... . 

Ba ............................................... . 

La ............................................... . 

Ce ............................................... . 

Nd ............................................... . 

Sm ............................................... . 

Eu ............................................... . 

Tb ............................................... . 

Yb ............................................... . 

Lu ............................................... . 

Hf ............................................... . 

Ta ............................................... . 

Th ............................................... . 

u ................................................ . 

F-statistic 

0.019 

<.001 

1.979 

.077 

.597 

.481 

.160 

2.605 

.645 

3.000 

.148 

.054 

.284 

.557 

2.063 

1.673 

2.042 

.349 

3.138 

1.548 

.665 

2.195 

1.447 

2.864 

2.704 

2.053 

.067 

1.947 

The determination of barium is complicated by the 

presence of fission product 103Ru. The 497.1 ke V line from 103Ru interferes with the principle gamma-ray of 131Ba at 

496.4 keV. The half-life of 131Ba is 12 days and of 103Ru is 

39.4 days; therefore, the longer the delay in counting for 131Ba, the more significant is the interference from 103Ru. 

Since no suitable interference-free line of 103Ru is available 

to compute a correction factor for spectral interference, the 

factor was determined by irradiating an aliquot of uranium 

standard and determining the amount of 103Ru produced by 

uranium fission. This time-dependent correction can then be 

applied after determination of the uranium abundance. In 

the initial compilation of SD0-1 analysis (Kane and others, 

1990), a correction for this interference had not been 

applied, and the results from the 124 keV line in the first 

planar count were unacceptable. In this work, the correction 

has been applied to the barium results determined using the 

496 keV line, and the agreement of the corrected results 

with "recommended values" is significantly improved. In 

an earlier compilation of SD0-1 (Kepferle and others, 

Table 3. Fission product correction factors (apparent j.Lg/g 

elementlj.Lg/g U) 

95Zr ...................... 11.3 

99Mo..................... .85 

141Ce..................... .29 

147Nd..................... .23 153Sm . . . . . . . . . . . . . . . . . . . . .00008 

140La..................... .002693 [exp (0.01497 td)-1.0] 131Ba..................... 2.8 [exp (0.0402 td)] 

1985), the barium data also suffer from the same fissionproduct interference. 

Unlike the spectral interference from a different 

nuclide produced by uranium fission, the interferences to 

Mo, Zr, La, Ce, Nd, and Sm are caused by the formation of 

the indicator radionuclides of those elements by uranium 

fission. The correction factors for these element were 

determined both experimentally and theoretically by calculation (Baedecker and McKown, 1987). The interference 

correction to La is complicated because the fission of 

uranium produces the 12.8 d 140Ba isotope that then decays 

to the 40.3 h 140La. Therefore, the amount of interference is 

dependent upon the growth and decay of 140La during the 

delay time, td, between irradiation and counting. The 

corrections to the La abundances were made using the 

time-dependent equation in table 3. The constants were 

determined using the Bateman equation. 

All these corrections are applicable to the neutron 

activation analysis of a material containing uranium, and 

even in geochemical samples containing "normal" relative 

concentrations of uranium, the interference from fission 

products can be significant. For example, the SGR-1 

sample included in this study required a 16-percent correction to Mo values and 2.6-percent and 4-percent corrections 

to the La and Ce data, respectively. The high relative 

concentration of U in SD0-1 produced corrections of 30 

percent for Mo and N d and 11 percent and 16 percent for La 

and Ce, respectively; and the apparent concentration of Zr 

due to fission products was 600 f.Lg/g. 

Spectral interferences from the high uranium content 

also complicated the determination of Lu. The 209.8 keV 

gamma-ray line of 239Np, an activation product of 238U, is 

1.4 keV away from the principal gamma-ray line of 177Lu 

used to assay Lu. The resolution of the HPGe detectors used 

was approximately 1.2 keV in this region (1.85 keV 

FWHM at the 1332 keV line of Co); and because complete 

resolution of the uranium peak from the assay peak for Lu 

is not possible, a doublet results. If the U/Lu ratio is small, 

the interference on Lu by U is small and can be determined 

using other uranium lines and the known intensity ratios. 

However, as the U/Lu ratio increases, the size of the 

uranium peak increases, and the determination of Lu 

becomes increasingly difficult. The doublet produced by U 

e39Np) and Lu for SD0-1 is shown in figure 1. The relative 

Instrumental Neutron Activation Analysis of Devonian Ohio Shale SD0-1 03 
+ 

239 Np 

0 

Figure 1. The lu/U{Np) doublet prior to interactive fitting. 

concentrations of U and Lu in SD0-1 still permitted the 

determination of Lu by performing interactive graphic 

plotting and fitting of the pair as described by Grossman and 

Baedecker (1986). Figure 2 shows the results of fitting and 

the residuals of the fit. Agreement between the 7- and 

14-day counts suggests that the fitting routine successfully 

determined the peak areas for Lu and U. The accuracy of 

the Lu data is often evaluated by looking at the relative 

positions of Yb and Lu in a chondrite normalized plot of 

0 _nn/l n n nO Q 

-3.5 

Figure 2. The lu/U{Np) doublet after interactive fitting. 

04 The USGS Reference Sample Devonian Ohio Shale SD0-1 

0 

~ 100 

a: 

~ 

a: 

a so z 

0 

:I: 

~ _.J 

a.. 

:::?i 20 

~ 

LA CE PR NO PM SM EU GO TB OY HO ER TM YB LU 

RARE EARTH ELEMENT 

Figure 3. Chondrite normalized rare earth plot of SD0-1. 

rare·earth abundances. Figure 3 shows such a plot, and the 

smooth transition from Yb to Lu indicates high-quality Lu 

data. 

ACKNOWLEDGMENTS 

My thanks to Mike Pickering for his dedication 

during the weighing and data-acquisition phases of this 

project and to Phil Baedecker and Jeff Grossman for their 

technical and editorial suggestions. 

REFERENCES 

Baedecker, P.A., and Grossman, J.N., 1989, The computer 

analysis of high resolution gamma-ray spectra from instrumental activation analysis experiments: U.S. Geological 

Survey Open-File Report 89-454. 

Baedecker, P.A., and McKown, D.M., 1987, Instrumental neutron activation analysis of geochemical samples, in Baedecker, P.A., ed., Methods for Geochemical Analysis: U.S. 

Geological Survey Bulletin 1770, p. H1-H14. 

Baedecker, P.A., Rowe, J.J., and Steinnes, Eiliv, 1977, Application of epithermal neutron activation in multielement analysis of silicate rocks employing both coaxial Ge(Li) and low 

energy photon detector systems: Journal of Radioanalytical 

and Nuclear Chemistry, v. 39, p. 239-254. 

Gordon, G.E., Randle, Keith, Goles, G.G., Corliss, J.B., Beeson, M.H., and Oxley, S.S., 1968, Instrumental activation 

analysis of standard rocks with high-resolution X-ray detectors: Geochemica et Cosmochimica Acta, v. 32, p. 369-396. 

Grossman, J.N., and Baedecker, P.A., 1986, Computer graphics 

for quality control in the INAA of geological samples: 

Journal ofRadioanalytical and Nuclear Chemistry, v. 113, p. 

43-59. 

Hertogen, Jan, and Gijbels, R., 1971, Instrumental neutron 

activation analysis of rocks with low-energy photon detector: 

Analytica Chimica Acta, v. 56, p. 61-82. 
Jacobs, J.W., Korotev, R.L., Blanchard, D.P., and Haskin, L.A., 

1977, A well tested procedure for instrumental neutron 

activation analysis of silicate rocks and minerals: Journal of 

Radioanalytical and Nuclear Chemistry, v. 40, p. 93-114. 

Kane, J.S., Arbogast, Belinda, and Leventhal, Joel, 1990, Characterization of Devonian Ohio Shale SD0-1 as a USGS 

geochemical reference sample: Geostandards Newsletter, v. 

14, p. 169-196. 

Kepferle, R.C., de Witt, Wallace, Jr., and Flanagan, F.J., 1985, 

Ohio Shale (Devonian), SD0-1, from Rowan County, Kentucky: U.S. Geological Survey Open-File Report, p. 85-145. 

Landsberger, Sheldon, 1989, Update of uranium fission interferences in neutron activation analysis: Chemical Geology, v. 

77, 65-70. 

Laul, J.C., 1979, Neutron activation analysis of geological materials, Atomic Energy Review, v. 17, p. 603-695. 

Instrumental Neutron Activation Analysis of Devonian Ohio Shale SD0-1 05 

Chapter E 

Relation Between Volatile Components and 

Loss on Ignition as Applied to the Analysis 

of USGS Reference Devonian Ohio Shale 

SD0-1 and Rare Earth Element Analyses 

By MIROSLAV HUKA and IVAN RUBESKA 

U.S. GEOLOGICAL SURVEY BULLETIN 2046 

THE USGS REFERENCE SAMPLE DEVONIAN OHIO SHALE SD0-1 

CONTENTS 

Abstract El 

Introduction El 

Relation of Volatile Components to LOI El 

Normal Igneous Rocks El 

The Effect of Sulfidic Sulfur E2 

The Effect of Inherent Sulfate Occurrences on LOI E3 

The Effect of Organic Carbon on LOI E3 

Experiment Parameters E3 

Results and Discussion E4 

Conclusion E4 

References ES 

TABLES 

1. Reactions during ignition and their effect on the relation between LOI and I 

volatile components E2 

2. Results of major rock-forming constituent analyses of SD0-1 E4 

3. Volatile components as measured in SD0-1 E4 

4. Calculations for correction of measured volatile components to account for ignition 

reactions ES 

5. Results for rare earth elements in SD0-1 ES 

Relation Between Volatile Components and 

Loss on Ignition as Applied to the Analysis of 

USGS Reference Devonian Ohio Shale SD0-1 

and Rare Earth Element Analyses 

By Miroslav Huka and Ivan Rubeska 1 

Abstract 

In organic-rich shales, hydrogen bound to hydrocarbons is oxidized to water and measured together with 

constitutional water, H20+. The amount of hydrogen 

released from the organic matter may be assessed from 

the difference between the experimental loss on ignition, 

after correction for oxidation of ferrous iron and pyritic 

sulfur, and the sum of the experimentally measured volatile components, that is, sulfur, organic carbon (Corg), 

C02 , and the measured H20+. This approach has been 

applied to the analytical data for the reference shale 

SD0-1 to improve the overall summation of major constituents, which should total 100±1 percent. Results for 

the rare earth elements determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), 

after two different separation procedures, are also presented. All results for SD0-1 in this report were included 

in the compiled data base from which recommended 

concentrations were derived. 

INTRODUCTION 

Chemical analysis of shales rich in organic matter for 

the major components included in a typical "silicate analysis" presents certain difficulties in achieving the expected 

summation to approximately 100 percent. These difficulties 

are caused mainly by the fact that oxygen, one of the main 

constituents, is not determined independently. Instead, the 

oxygen content is calculated on the basis of the assumptions 

that the standard oxide representation of the cations is 

correct and that the volatile components can be either 

accurately measured or reasonably estimated from loss on 

ignition (LOI). The relatively high content of organic 

carbon that usually occurs together with sulfide minerals in 

the shales has a deleterious influence on the results from 

Manuscript approved for publication September 15, 1992. 1

Geological Survey of Prague, Czechoslovakia 

several of the well-established procedures used in silicate 

analysis, invalidating these assumptions. Organic carbon 

and sulfide mineralization prevent accurate measurement of 

ferrous iron and H20 + and also affect the relation of H20 +, 

ferrous iron, sulfur, Corg• and C02 to LOI. However, if the 

relation of LOI to iron speciation and the volatile components can be well understood, the content of hydrogen 

bound in organic matter can be calculated for the final 

summation of the analysis. In this report, the LOI relation to 

other components is first discussed on a general level, and 

then the appropriate calculations are applied to data 

obtained for SD0-1 using common laboratory procedures 

for silicate rock analysis. All ignition reactions pertinent to 

the discussion that follows, the errors in LOI and total 

results that ignition reactions introduce, and appropriate 

corrections are summarized in table 1. 

RELATION OF VOLATILE COMPONENTS 

TO LOI 

Normal Igneous Rocks 

In typical silicate rock analysis, LOI approximates 

the sum in the sample of volatile components, mainly C02 

expelled from carbonate, S, H20 +, and halogens. Therefore, it should be possible to calculate one of the volatile 

components, H20+, by difference from the rest and the 

measured LOI (LOiexp). However, some of the sample 

constituents change during ignition, causing analytical error 

to be introduced in the estimation of volatile components 

from LOiexp· Proper corrections must be introduced to 

obtain a corrected value, LOicorr• which will equal, rather 

than only approximate, the sum of the volatile components. 

The effect on LOiexp of oxidizing ferrous iron is a 

well-known example. Commonly, in the analysis of igneous rocks, the LOiexp is decreased in comparison to LOicorr 

by the weight gain from adding oxygen to the sample during 

Relation Between Volatile Components and Loss on Ignition, Analysis of USGS Reference Shale SD0-1 and REE Analyses El 
Table 1. Reactions during ignition and their effect on the relation between LOI and I volatile components 

1 

2 

3 

4 

5 

6 

7 

8 

9 

Sample Cation stays in 

components ignited residue as 

MC03 MO 

Mx0yXnH20 MxOy 

MX MO orM20 

MF+nH2Si03 MO 

FeO Fe20 3 

FeS Fe20 3 x 

FeS2 Fe20 3 

FeS2 + (Ca,Mg)C03 Fe20 3+a(Ca,Mg)S04 

CxHyOzN 

M =alkali or alkaline earth 

X=Cl, Br, I 

Reactions: Apply to: 

Volatile 

components as 

C02 

H20 

x2 

H2SiF6 

so 

so;sxo.3742 

(4-a)S02+C02 

C02 +H20+NO 

Correction for 

LOicorr = 

I volatile components 

FeOXO.lll 

SX0.7484 

0.3742+Signitx 1.497 

Notes 

Uncertain but generally 

neglibigle. 

With S02 fixation. 

H20 + determination biased high by 

oxygen fixed in oxidizing Horg· 

signit = s content in ignited residue 

Horg =hydrogen in organic matter 

1-5 

Up to 8 

Up to 9 

Typical igneous rocks; occasionally reactions 6-7 also apply, but the corrections will be negligibly small 

Sulfide-rich rocks, but 5-8 will dominate errors 

Organic-rich rock 

ignition, oxidizing divalent iron to trivalent. In the absence 

of sulfur, the correction is rather straightforward and may 

be expressed as 

LOicorr=C+C02 + H20 + = LOiexp + FeO x 0.111 

=I volatile components. (1) 

The multiplication factor 0.111 is the molecular mass ratio 

of Fe20 3 to 2Fe0 minus 1 , and the product expresses the 

mass increase of the ignited sample due to fixation of 

oxygen through oxidation of the originally divalent iron. 

After making this correction to LOiexp• the calculation 

of H20+ in "typical" igneous rocks from LOicorr and the 

other volatile components can be made with considerable 

accuracy. 

Also during ignition, the halogens F and Cl are 

partially lost from samples. At high ignition temperatures, 

when H20+ is released, pyrohydrolysis takes place, and Cl 

volatilizes as HCI. The process is supported by the Si02 

present, which acts as a nonvolatile acid. Fluorine behaves 

in a similar way, but the HF formed reacts immediately with 

Si02 and volatilizes as SiF4 or H2SiF6 • The losses are 

greater for acid rocks than for basic ones. In most cases, the 

error in Si02 affecting the final analytical summation is 

negligible, and inclusion of halogens in the sum of volatile 

components is sufficient in obtaining a value for LOicorr 

from which a calculated H20+ can be accurately derived. 

It was noted above that FeO, normally measured 

straightforwardly in "typical" silicate rock analysis, cannot 

be measured directly in the presence of organic matter. Also 

ferrous iron in pyrite is not measured using the standard 

ferrous iron procedure. Obtaining LOicorr for SD0-1, then, 

E2 The USGS Reference Sample Devonian Ohio Shale SD0-1 

is not straightforward; the remainder of this section examines the problem. 

The Effect of Sulfidic Sulfur 

If sulfur is present in appreciable amount (>0.2 

percent), the error in LOiexp becomes more complicated. 

Most often the sulfur in shales occurs bound to iron either as 

pyrite/marcasite (FeS2) or as pyrrhotite (FeS). However, all 

iron is typically reported as Fe20 3 in rock analyses. This 

misrepresentation of iron speciation in the final summation 

of oxides results in a positive numerical error since both the 

sulfur actually bound to iron and the "sulfur equivalent" 

oxygen (SOQ) reportedly bound to iron are included. The 

oxide summation is corrected by subtracting SOQ from the 

initial summation. For pyrite the SOQ is S X0.25 

(16/2X32.06), whereas for pyrrhotite it is Sx0.5 

(16/32.06). Thus, accurate correction requires knowledge 

of the mode of sulfur occurrence in the sample. 

It is possible to differentiate between the pyrite and 

pyrrhotite by showing differences in the solubilities of the 

two materials or by using a qualitative test; the presence of 

pyrrhotite is revealed by the smell of H2S when adding acid 

to the sample. A common-sense judgment can also be used, 

based on the fact that pyrrhotite generally occurs in basic 

rocks, whereas pyrite and marcasite are common in shales. 

Further discussion will therefore be limited to considering 

occurrences of pyrite in the sample. 

In addition to the SOQ correction in the major oxide 

total, a correction of LOiexp must also be introduced for the 

oxygen mass added to oxidize pyritic (divalent) iron to 
Fe20 3 . This oxygen increases the mass of the ignited 

sample and reduces LOiexp in comparison to LOicorr• as 

already discussed for samples containing ferrous oxide. 

Assuming that the sulfur is bound more or less exclusively 

to iron, this correction is made by multiplying the sulfur 

content by 0.3742: 

However, this correction might be inadequate if the 

sample contains CaC03 or MgC03 , either of which can fix 

S in the ignited sample as sulfate. The direct determination 

of C02 as one of the volatiles in the sample gives an 

indication of the potential magnitude of this problem. 

Equation 2 also neglects oxidation of any ferrous iron in 

addition to pyritic iron. To account for both sulfur fixation 

and that oxidation, equation 2 becomes 

LOicorr=(S-Signit)+C02+ H20+ 

=LOiexp + Fe0X0.111 +S X0.3742+Signitx 1.497. (3) 

The Effect of Inherent Sulfate Occurrences on 

LOI 

Although the discussion above assumed that essentially all sulfur in the sample occurred as pyrite or pyrrhotite, sulfur may also be present in the sample initially as 

sulfate. Sulfates of alkali and alkaline earth elements are 

unaltered during ignition, whereas sulfates of heavy or 

trivalent metals (for example, Fe, Mn, Cu) decompose, 

releasing S03 . Oxidation of sulfide to sulfate is a common 

natural geochemical process and may even take place 

during storage of the sample in the laboratory, particularly 

for samples containing considerable H20- stored at high 

temperatures. 

The presence of alkaline earth sulfates in the sample 

generally results in an analytical summation low by an 

amount equal to the excess oxygen in sulfate compared to 

oxide, ssulfx 1.497. The presence of alkaline earth sulfates, 

however, does not cause an error in the estimation of H20 + 

from equations 2 or 3. On the contrary, the presence of 

heavy metal sulfates would overestimate H20 +, using those 

equations, by the excess of oxygen in sulfate compared to 

oxide, that is, by ssulfx 1.497. 

The Effect of Organic Carbon on LOI 

During ignition to determine LOiexp• all organic 

matter in the sample is oxidized and volatilized: 

Volatile components 

=(CHON)org +S+C02+ H20.:e. (4) 

The ignition should proceed slowly at a temperature that 

avoids melting of the sample; otherwise, incomplete oxidation of carbon and partial reduction of Fe20 3 to FeO might 

occur in the molten sample. Either would result in a low 

LOiexp• and an error in the calculation of H20+. 

Assuming that complete oxidation of organic matter 

also occurs during determination of H20 + in organic-rich 

samples, the measured H20+ will be higher than the 

amount calculated from LOI and the other individual 

volatile components (eq. 2). This difference occurs because 

organic hydrogen will be oxidized to water and included in 

the measured H20 + result. The excess water can be used to 

estimate the hydrogen bound in hydrocarbons: 

(5) 

Further, the calculated value can be used to approximate the 

true constitutional water in the sample, which cannot be as 

accurately measured in organic-rich samples as in "typical" 

rocks. 

EXPERIMENT PARAMETERS 

The SD0-1 sample was analyzed on an "as received" 

basis, except for LOiexp• which was determined on the dry 

sample. Duplicate analyses from each of two bottles of 

SD0-1 were made using methods routinely applied in the 

authors' laboratory (Weiss, 1983; Huka and Rubeska, in 

press). The samples were analyzed as part of a batch 

( ~200) of routine samples. The major oxides that are 

required for the analytical summation were determined from 

a single decomposition of the sample using a mixture of HF, 

HN03 , and H2S04 • A 0.200-g sample was decomposed in 

a specially designed polytetrafluoroethylene vessel assembly where the evolving SiF4 was sorbed on KN03 • After 

hydrolysis of the resulting K2SiF6 , Si was determined by 

titrating the released HF with NaOH (Huka and Rubeska, in 

press). Fluorides in the sample residue were removed by 

fuming after the addition of H3B03 and HN03 • About 50 

mL of distilled water were added to the dry residue, and the 

sample was left on a warm plate to hydrolyze for 20 to 30 

minutes. Then, 10 mL 1:1 HCI, with 0.2 g Cs2C03 and 

0.25 mL H2S04 as an ionization buffer, were added. The 

resulting clear solution was transferred to a 100-mL volumetric flask and made up to volume with distilled water. Li, 

Na, K, Mg, Ca, Ti, and Mn were measured by flame atomic 

absorption spectrometry (Fl-AAS). Fetot and P20 5 were 

determined by spectrophotometry, using the sulfosalicylic 

acid and molybdenum blue procedures, respectively. AI 

was determined by the Sajo (Weiss, 1983) chelatometric 

method with ethylenediamine tetraacetic acid. 

Moisture (H20-) was determined to be 0.79 weight 

percent by drying the weighed sample at 11 0°C for 4 hours 

and reweighing. LOI was determined on the dry sample, 

Relation Between Volatile Components and Loss on Ignition, Analysis of USGS Reference Shale SD0-1 and REE Analyses E3 
Table 2. Results of major rock-forming constituent analyses of SD0-1 

[In weight percent] 

Split: 393a 393b 768a 768b 

Component 

Si02 49.43 49.29 49.62 49.26 

Al20 3 12.06 12.13 12.10 12.03 

Fe20 3 3.03 2.98 3.04 3.07 

FeO 5.64 5.66 5.59 5.63 

MnO .041 .040 .040 .042 

MgO 1.47 1.46 1.48 1.49 

CaO 1.01 1.07 1.08 1.06 

Li20 .006 .006 .006 .006 

Na20 .45 .43 .43 .42 

K20 3.24 3.23 3.23 3.22 

P20s .01 .01 .01 .01 

which was ignited at 1 ,050°C for 20 minutes and 

reweighed. Carbonate was measured by the release of C02 

from the sample by boiling with H3PO 4 and its sorption on 

Ba(OH)z; the sorbed C02 was titrated using a Stroehlein 

Coulomat Model 7012. Total carbon was determined from 

the C02 released by igniting the sample in a stream of 

oxygen, measured as just described for C02 in the sample. 

Sulfur was determined after its release as S03 by heating the 

sample with a catalyst, V 20 5+ U30 8 , in a stream of 

nitrogen. After sorption, the S03 was titrated with coulometrically generated iodine, using biamperometric indication of the endpoint. 

Rare earth analyses were performed by inductively 

coupled plasma atomic emission spectrometry following 

two different procedures for the separation of the rare earth 

elements (REE) from the sample matrix. One using ionexchange chromatography was described by Sulcek and 

others (1989); the second involved an organic solvent 

extraction of ion associates of REE nitrates with trioctylphosphine oxide (Weiss and others, 1990). 

RESULTS AND DISCUSSION 

Results for major-oxide analyses of SD0-1 are presented in table 2. Results for the volatile components that 

were measured directly are presented in table 3. Using the 

logic of the preceding section describing the potential 

analytical errors in analytical summation and LOI (summarized in table 1), corrections for those errors were made, as 

follows. 

Since it was not possible to determine FeO directly in 

the presence of organic matter, the assumption was made 

that all S present occurred in pyrite and that a corresponding 

stoichiometric amount of Fe +2 occurred in the sample. The 

balance of the total iron was assumed to be ferric iron. Little 

carbonate was measured in SD0-1; thus, no appreciable 

E4 The USGS Reference Sample Devonian Ohio Shale SD0-1 

Table 3. Volatile components as measured in SD0-1 

[In weight percent] 

Split: 393a 393b 768a 768b 

Component 

F <0.01 <0.01 <0.01 <0.01 

ctot 10.41 10.40 10.48 10.57 

C02 .72 .70 .81 .84 

Corg =Ctot -Cco2 10.21 10.21 10.26 10.35 

s 5.04 5.05 4.99 5.03 

HzO!eas 9.66 9.46 9.53 9.28 

Volatile components 25.63 25.42 25.59 25.49 

LOiexp 21.59 21.45 21.56 21.51 

amount of S is expected to be fixed in the ignited residue as 

sulfate. LOicorr from equation 3 is therefore reduced to 

LOicorr=LOiexp +Sx0.3742, (6) 

which accounts for oxidation of pyrite to hematite. 

From this calculated LOicorr• values for volatile 

components, Horg• and true H20+ are derived. Table 4 

summarizes these calculations and presents the analytical 

summation for the analyses, based on those calculations and 

the major-oxide analyses presented in table 2. The totals are 

not ideal, due to the uncertainties involved in the approach. 

However, as can be seen, the approach improves the 

uncorrected totals significantly. 

The REE data by ICP-AES following the two separations are presented in table 5. They agree well with 

recommended concentrations (Kane and others, 1990) that 

were derived from these and other contributed data. However, the extraction procedure apparently provides higher 

results than those obtained using the ion-exchange procedure. This difference probably occurs because, for the 

extraction, calibration solutions were carried through the 

separation; whereas for ion exchange, they were not. An 

ion- exchange yield of less than 100 percent would cause a 

low bias in the sample analyses. No such bias would occur 

if extraction yields were less than 100 percent, but constant 

for sample and calibration solutions. 

CONCLUSION 

The results presented in this paper formed a part of 

the compiled data base from which the recommended 

concentrations were derived for the gas shale reference 

sample SD0-1. The methods used in our laboratory produce analytical results in excellent agreement with the final 

recommended concentrations for both major oxides and rare 

earth elements. Applying the described corrections to LOI 

provides acceptable major-oxide summations for the analysis of organic-rich and sulfur-rich samples, which are 

generally quite difficult to achieve for such samples. 
Table 4. Calculations for correction of measured volatile components to account for ignition reactions 

Calculation 

SOQ = (S )(0. 25) 

LOicorr=LOiexp +(S)(0.3742) 

LOicorr=S+Corg +C02+ H20~eas 

excess O=eq. 3 LOicorr-eq. 2 LOicorr 

Horg =excess 0-7- 8 

excess H20+ =excess 0+ Horg 

0;ue=H 0~eas -excess H20+ 

Major oxide summation 

C02, Corg, S summation 

H20-

H20:Ue 

Horg 

SOQ 

Analytical summation, whole rock 

Result 

in weight percent 

-1.26 

23.43 

25.54 

2.11 

.27 

2.38 

7.12 

76.29 

16.06 

. 79 

7.12 

.27 

-1.26 

100.53 

Table 5. Results for rare earth elements in SD0-1 

[In J.Lg/g; NA, not analyzed] 

Jon exchange Extraction 

Split: 393 768 393 768 

Element 

La 35.3 34.7 38.6 37.3 

Ce 71.6 70.9 86.1 84.1 

Pr 8.00 7.79 8.55 8.75 

Nd 35.3 36.0 35.5 35.9 

Sm 7.71 7.36 8.47 7.91 

Eu 1.46 1.48 1.65 1.69 

Gd 7.06 7.11 8.40 7.80 

Tb .81 1.04 .91 1.01 

Dy 6.22 6.33 7.14 7.08 

Ho 1.22 1.10 1.31 1.46 

Er 3.83 3.00 4.00 3.96 

Tm .49 .50 <.40 <.40 

Yb 3.05 3.11 3.80 3.80 

Lu .49 .49 .55 .55 

y 34.8 35.0 40.6 40.2 

Sc 13.0 12.5 NA NA 

Comment 

Oxygen equivalent of sulfur for pyritic iron represented 

as FeO in major oxide table 1; see text E2. 

Oxygen added in oxidizing pyrite to Fe20 3 ; see eq. 2. 

Alternative calculation to that above; see eq. 3. 

Fixed on oxidation of organic H; see text E3. 

H20 graumetric factor. 

See text E3. 

Table 1, average 

Unbiased measured volatiles, table 2. 

Moisture; see text E3 . 

Calculated above. 

Calculated above. 

Calculated above. 

Meets 100± 1 test for overall analytical accuracy. 

REFERENCES 

Huka, Miroslav, and Rubeska, Ivan, in press, An expeditious wet 

chemical procedure for silicate analysis with titrimetric determination of silica: Geoanalysis 90 Symposium volume, 

Geological Survey of Canada Paper. 

Kane, J.S., Arbogast, B.F., and Leventhal, J.S., 1990, Characterization of Devonian Ohio Shale SD0-1 as a USGS 

geochemical reference sample: Geostandards Newsletter, v. 

14, p. 169-196. 

Sulcek, Zdenek, Rubeska, Ivan, Sixta, Vaclav, and Paukert, 

Tomas, 1989, Determination of REE and Y in rocks using the 

Plasma 2 ICP emission spectrometer: Atomic Spectroscopy, 

v. 10, p. 4-9. 

Weiss, Dalibor, ed., 1983, Methods of chemical analysis of the 

Geological Survey of Prague. 

Weiss, Dalibor, Paukert, Tomas, and Rubeska, Ivan, 1990, 

Determination of REE and Y in rocks by ICP-AES after 

separation by organic solvent extraction: Journal of Analytical Atomic Spectrometry, v. 5, p. 371-375. 

Relation Between Volatile Components and Loss on Ignition, Analysis of USGS Reference Shale SD0-1 and REE Analyses E5 

Chapter F 

A Study to Determine Sources of 

Interlaboratory Variability in 

Measured Loss on Ignition (LOI) for 

Devonian Ohio Shale SD0-1 

By JEAN S. KANE and CAROL j. SKEEN 

U.S. GEOLOGICAL SURVEY BULLETIN 2046 

THE USGS REFERENCE SAMPLE DEVONIAN OHIO SHALE SD0-1 

CONTENTS 

Abstract Fl 

Introduction Fl 

Review of compiled data for FeO and Volatile Components Fl 

Experiment Parameters F3 

Moisture (H20 -) and LOI F3 

Determination of Ferrous Iron F4 

Measurement of CHNS F4 

Results and Discussion F4 

Moisture (H20-) F4 

LOI FS 

FeO and S in Ignited Sample FS 

CHN in Both "As Received" and Ignited Sample F6 

Analytical Total F6 

Conclusion FS 

References FS 

FIGURES 

1, 2. Graphs showing: 

1. Moisture results after cyclic drying and reabsorption FS 

2. LOI as a function of temperature, illustrating interaction between temperature 

and bottle components of variance FS 

TABlES 

1. Compiled data for volatile components F2 

2. Moisture: Evaluation of bottle differences F4 

3. Loss on ignition: Evaluation of bottle and ignition-temperature differences F6 

4. Reactions during ignition of sample F6 

5. FeO and S in ignited sample residue and weight gain calculations F7 

6. CHN results for SD0-1 F7 

7. Alternative estimates of the sum of volatile components FS 

A Study to Determine Sources of Interlaboratory 

Variability in Measured Loss on Ignition (LOI) for 

Devonian Ohio Shale SD0-1 

By Jean S. Kane and Carol j. Skeen 

Abstract 

Studies are reported that investigate the several 

components in the sizable (approximately 10 percent 

relative) variance between laboratories in measuring loss 

on ignition for the reference sample Devonian Ohio Shale 

SD0-1. This large variance is a major factor in the poor 

analytical summation for the major constituents of the 

shale that was noted in the original compilation report 

(Kane and others, 1990). 

INTRODUCTION 

In reporting recommended concentrations for constituents in the reference shale sample SD0-1, difficulty was 

encountered in verifying the overall SD0-1 analyses using 

a major-oxide summation to 100± 1 percent (Kane and 

others, 1990). Such verification is very common in rock 

analysis (Abbey, 1983; Lechler and Desilets, 1987), but it 

is less applicable to the analysis of either organic-rich or 

sulfur-rich samples. For example, totals of the recommended major-oxide concentrations (including estimated 

volatile components) for marine mud (MAG-1), Cody 

Shale (SCo-1), and Green River Shale (SGR-1) reference 

samples are 105.5, 100.35, and 88.82 percent, respectively 

(Gladney and Roelandts, 1988). 

The difficulty results from the inability to measure 

individual volatile components accurately and from the 

considerable error that results from using measured loss on 

ignition (LOI) as a measure of the sum of volatile components (Lechler and Desilets, 1987; Potts, 1987; Huka and 

Rubeska, chap. E, this vol.). The important volatile components are water (both moisture, H20-, and essential 

water, H20+), carbon dioxide (C02), sulfur (S), and 

organic matter. Only H20-, C02 , and S can be measured 

directly. 

In most rock analyses, total water (H20tot) and 

moisture (H20-) are measured, whereas essential, or 

Manuscript approved for publication September 15, 1992. 

bound, water (H20+) is calculated by difference. For 

organic-rich samples, H20tot as measured includes both the 

H20 + in sample and the water resulting from combustion of 

organic matter. H20 + calculated in the normal way is 

biased high by the organic matter contribution to H20 +. 

Although total carbon (Ctot) and C02 can be measured readily, Corg is most often determined by difference 

between Ctot and Ccarbonate (C02 X0.274). From Corg• total 

organic matter can be estimated, but uncertainties are 

considerable. Ratios of C to H in organic matter (as 

determined by CHN analysis of organic matter isolated 

from shale by Soxlet extraction) are biased low, overestimating Horg (Frost and others, 1985). This error occurs 

because low-molecular-weight organic compounds are preferentially extracted. Correction of H20tot for the Hor 

contribution will be correspondingly inexact. g 

, Frost and others (1985) achieved totals generally 

between 98 and 101 percent, but occasionally as low as 96 

percent or as high as 103 percent, for the analyses of a large 

number ( -250) of Devonian shales from Illinois. They 

assumed that H20 + could be fairly accurately estimated 

from a hydrogen mass balance after measuring Htot and 

moisture and calculating an organic hydrogen value. Huka 

and Rubeska (chap. E, this vol.) present another approach 

to achieving an accurate analytical summation by estimating 

H20+ from the experimental loss on ignition (LOiexp). 

They outline corrections to LOiexp that are required for LOI 

to approximate more accurately the sum of volatile components in sample. This paper reviews the compiled data 

relevant to LOI and presents the experiments undertaken in 

our laboratory to better understand the various components 

of uncertainty in LOI. 

REVIEW OF COMPILED DATA FOR FEO AND 

VOLATILE COMPONENTS 

Table 1 includes all previously contributed and newly 

reported data for LOI, ferrous iron, and individual volatile 

components, and for moisture, H, and N. The moisture, H, 

A Study to Determine Sources of Interlaboratory Variability in Measured Loss on Ignition (LOI) for Devonian Ohio Shale SD0-1 F1 
Table 1. Compiled data for volatile components 

Moisture Total carbon 

(weight percent) (weight percent)-

Continued 

Data lab ID Method and comment 

Data lab ID Method and comment 

0.50 Lab 15 

.71 Lab 55 11 0°C for 1 hr 10.89 Lab 38 

.73 Lab 31 11.80 Lab 39 

.80 Lab 14 11 0°C for 4 hr 13.79 Lab 31 

.99 Lab 6 

1.06 Lab 16 Carbonate C as C02 

1.58 Lab 17 (weight percent) 

1.68 Lab 22 110°C for 18 hr Data lab ID Method and comment 

1.73 Lab 2 

1.79 Lab 3 0.45 Lab 13 

1.80±0.29 This work 110°C 1 hr or 18 hr .55 Lab 57 

.75 Lab 4 

Constitutional water .77 Lab 14 

(weight percent) .63--0.81 This work Assuming measured C in 

lab ID Method and comment residue of 500°C ash Data approximates carbonate C 

2.93 Compilation Calculated .85 Lab 15 

Average (See Kane and others, 1990) .99 Lab 28 

4.41 17 Unknown .99 Lab 29 

7.12 14 Calculated 1.07 Lab 1 

(See Huka and Rubeska, 1.08 Lab 27 

chap. E, this vol.) 1.25 Lab 37 

1.28 Lab 19 

Hydrogen Nitrogen 1.46 Lab 3 

(weight percent) (weight percent) 

Data lab ID Data lab ID Organic C 

(weight percent) 

1.24 Lab 39 0.31 Lab 31 Data lab ID Method and comment 1.30 Lab 30 .31 Lab 38 

1.30 Lab 38 .32 Lab 34 8.30 Lab 20 Unspecified 1.33 Lab 23 .33 This work 8.79 Lab 20 Calculated by difference 

1.34 Lab 32 .34 Lab 32 (total-carbonate) 

1.34 This work .40 Lab 23 8.98 Lab 28 Leco 

1.35 Lab 34 .40 Lab 30 9.72 Lab 17 Unspecified 

1.40 Lab 29 1.21 Lab 39 9.73 Lab 13 Calculated 

1.45 Lab 55 10.08 Lab 23 Calculated 

1.83 lab 31 10.11 Lab 38 Unspecified 

10.19 Lab 55 Calculated Total carbon 10.20 Lab 7 Unspecified (weight percent) 10.44 Lab 23 Wet oxidation 

Data lab ID Method and comment 10.52 Lab 8 Unspecified 

11.30 Lab 39 Unspecified 

8.97 Lab 20 

9.27 Lab 27 Sulfur 

9.72±0.72 This work (weight percent) 

9.85 Lab 7 

Data lab ID Method and comment 9.96 Lab 6 

9.96 Lab 19 Sample as received 9.96 Lab 13 

9.98 Lab 8 4.90 Lab 29 

10.00 Lab 28 5.03 Lab 14 

10.09 Lab 17 Sum Corg+C02 5.06 Lab 19 

10.26 Lab 14 5.19 Lab 13 

10.36 Lab 23 1 ,800°C, combustion 5.23 Lab 15 

10.40 Lab 29 5.29 Lab 58 

10.40 Lab 30 5.30 Lab 28 

10.40 Lab 34 5.36 Lab 27 

10.43 Lab 32 5.38 This work Leco 

10.53 Lab 55 Combustion 5.70 Lab 57 

10.80 Lab 23 Wet oxidation 6.30 Lab 20 

F2 The USGS Reference Sample Devonian Ohio Shale SD0-1 
Table 1. Compiled data for volatile componentsContinued 

Sulfur 

(weight percent)-

Continued 

Data Lab ID 

Ignited sample 

0.71 Lab 21 

.43 This work 

1.41 This work 

Loss on ignition 

(weight percent) 

Data 

19.25 

19.43 

19.56 

19.56 

19.78 

20.82 

20.83 

20.91 

21.37 

21.38 

21.57 

21.63 

21.82 

21.90 

21.93 

22.00 

22.35 

22.37 

22.39 

22.84 

23.06 

23.08 

33.00 

Lab ID 

This work 

This work 

Lab 3 

Lab 1 

Lab 27 

This work 

Lab 13 

Lab 18 

Lab 58 

Lab 16 

Lab 6 

Lab 4 

Lab 17 

Lab 21 

Lab 15 

Lab 57 

Lab 26 

Lab 19 

Lab 14 

Lab 2 

This work 

Lab 22 

Lab 20 

Method and comment 

XRF 

Leco, 1 ,000°C 

Leco, 500°C 

Method and comment 

500°C, 1 hr 

500°C, 18 hr 

550°C, 1 hr 

800°C, 1 hr 

1,050°C, 20 min 

1,000°C, 1 hr 

1,000°C, 1 hr 

and N data were not included in the 1990 compilation (Kane 

and others). 

An examination of the compiled data reveals four 

points. First is the general lack of data for individual 

volatile components in comparison to major oxides, each of 

which was reported by 20 to 30 contributors. Second is that 

LOI, C02 , and H20- all show an unacceptably large 

variation between laboratories. For LOI, fewer than half the 

contributing laboratories reported ignition temperature, 

which significantly affects experimental LOI. For example, 

the omission of the obvious outlier value of 33-percent LOI 

results in the 3.5-percent absolute difference between the 

high and low laboratory average LOI. This variation results 

from several factors, one of which is the significant 

between-bottle variation for LOI noted in the 1990 compilation (Kane and others). Five of eight laboratories identified between-bottle variance, which may be equally significant for H20- and C02 , although the data reported does 

not permit assessment of that possibility. 

Variation of ignition temperature is the third factor 

contributing to between-laboratory variance. Laboratories 

reported using various ignition temperatures from 500°C to 

1 ,000°C. Although ignition to constant weight occurs 

within 1 hour at 1 ,000°C (Lechler and Desilets, 1987), it 

proceeds more slowly at lower temperatures. Therefore 

ignition at 500°C for one hour is incomplete and the LOI 

result is biased low. This factor will be treated more fully in 

the results and discussion section. 

Also, few laboratories indicated whether or not samples were ignited "as received" or after drying. If H20- was 

not reported separately, LOI was assumed to have been 

reported on an "as received" basis so that the final recommended LOI result includes H20- along with all other 

volatile components. Similarly, if H20- was reported 

separately, it was assumed that the reported LOI did not 

include moisture and that value was added, so that LOI as 

compiled would include it. If either (or both) of these 

assumptions is incorrect, that would account for a part of 

the observed between-laboratory variance in LOI results. 

The final point to note regarding the compiled data in 

table 1 is that LOI as measured does not accurately reflect 

the sum of volatile components (Lechler and Desilets, 1987; 

Huka and Rubeska, chap. E, this vol.; Potts, 1987). 

Therefore, LOI cannot be used with the major rock-forming 

oxides in achieving an accurate analytical summation. For 

typical rock analysis, the inaccuracy is due almost exclusively to the weight gain resulting from oxidation of ferrous 

oxide to ferric oxide (Lechler and Desilets, 1987). Since 

FeO and total iron can both be measured directly and 

accurately for most rocks, correction is straightforward. For 

sulfur-rich and organic-rich sedimentary rocks (and SD0-1 

is both), the error is of similar origin-oxidation of both 

pyritic iron and ferrous oxide to ferric oxide. Correction for 

this error is complicated in two ways. First is the inability to 

measure ferrous iron directly in the original sample due to 

interferences in the redox reactions for that measurement by 

both organic matter and sulfur. Second is an additional error 

in measured LOI due to the weight gain resulting from 

fixation of some sulfur as sulfate in the ignited sample. 

Correction for that error requires measurement of sulfur in 

the ignited sample; only one laboratory initially reported 

that measurement. 

This study focused on establishing the significance of 

between-bottle differences for H20-, C02 , and organic 

matter in sample and on the degree of ferrous iron oxidation 

and sulfur fixation during ignition. 

EXPERIMENT PARAMETERS 

Both H20- and LOI were measured following the 

standard procedures of the laboratory (Jackson and others, 

A Study to Determine Sources of Interlaboratory Variability in Measured Loss on Ignition (LOI) for Devonian Ohio Shale SD0-1 F3 
1987; Shapiro and Brannock, 1962), which involve overnight drying at 105°C and 1-hour ignition at 1,000°C. The 

H20- and LOI contents were determined in duplicate for 

four separate bottles to allow between-bottle analysis of 

variance (anova) calculations. The constituent concentrations were obtained as the differences in weight between "as 

received" and dried/ignited sample weights. 

Reabsorption of moisture by dried or ignited samples 

was measured as follows. Accurately weighed, dried/ignited samples, one from each bottle of SD0-1 , were stored 

in separate sealed vials. The second samples from each 

bottle were left exposed to a humid (>90 percent) laboratory atmosphere in open vials. Both groups were reweighed 

8 hours later, and the reabsorbed moisture was calculated by 

difference. The dried (but not ignited) samples were 

returned to the drying oven after reabsorption, and the 

process was repeated through three cycles. 

In addition to the standard ignition for 1 hour at 

1 ,000°C, three other time/temperature ignitions were done 

to assess variations in results attributable to drying time and 

temperature: 1 hour at 500°C; 18 hours at 500°C, and 1 hour 

at 800°C. LOI was generally determined on the "as 

received" sample; in some cases LOI was determined on the 

dried sample instead. 

Determination of Ferrous I ron 

For the ignited samples only, FeO was measured by 

titration with potassium dichromate to a diphenylamine 

sulfonate indicator endpoint using the procedure reported in 

Shapiro and Brannock (1962). The ash was first decomTable 2. Moisture: Evaluation of bottle differences 

[In weight percent; d.f., degrees of freedom] 

Bottle 

1 

6 

5 

4 

2 

7 

3 

Average, 

individual 

results, all 

bottles 

Bottle 

1 

4 

5 

6 

Resultovernight drying 

1.57±0.023 

1.64±0.015 

1.69±0.025 

1.73±0.03 

2.02±0.14 

2.04±0.021 

2.22±0.098 

1.84±0.29 

Result1-hr drying 

1.59 

1.70 

1.71 

1.62 

F-test data 

d.f.=7,13 

F=50.40 

Fcrit(0.95)=2.83 

Fcrit<0.99)=4.44 

F4 The USGS Reference Sample Devonian Ohio Shale SD0-1 

posed in the absence of air with a mixture of hydrofluoric 

and sulfuric acids. 

Measurement of CHNS 

Carbon, hydrogen, and nitrogen were measured in 

replicate samples from three bottles of SD0-1 using a 

Perkin Elmer Model 2400 CHN Elemental Analyzer; and S 

was measured using a Leco Model SC-132 sulfur analyzer 

on both "as received" and ignited samples. Measurements 

are based on combustion to convert the elements in sample 

to simple gases (C to C02 , H to H20, N to N2 , and S to 

S02). CHN are measured by thermal conductivity after 

chromatographic separation, and S is measured by an 

infrared detector (Leco, 1980, Perkin Elmer, 1988). These 

data allow estimation of homogeneity with respect to 

individual C, H, N, and S samples, which had not been 

possible before. 

RESULTS AND DISCUSSION 

Moisture (H20-) 

We have noted that several laboratories included 

moisture in their LOI values, since they ignited samples "as 

received." Subtle changes in the degree to which samples 

exhibit hygroscopic behavior and absorb atmospheric moisture are perhaps related to the between-bottle variation in 

the ratio of clay minerals to other principal components, 

namely pyrite and organic matter. Such between-bottle 

variation is evident from the inhomogeneity found with 

respect to Si02 , Al20 3 , and total iron reported as Fe20 3 , 

which has been documented (Kane and others, 1990). 

H20- measured in this work varied significantly 

between bottles, as shown in table 2. Overnight drying was 

used in this study; some laboratories (for example, Frost 

and others, 1985) employed much briefer drying times of 1 

hour. Presumably, this short time was intended to avoid the 

potential loss of volatile organic compounds from the 

sample (Jackson and others, 1987). Our results are among 

the highest moisture contents of the data contributed to the 

SD0-1 characterization, suggesting a high bias due to loss 

of organic matter during drying. However, a considerable 

fraction of the lost weight was restored as reabsorbed 

moisture in rather short (8-hour) intervals, and more than 85 

percent of the lost weight was restored in a 3-day exposure 

to moist air (fig. 1). Also, moisture determined subsequently in our laboratory using a drying time of 1 hour gave 

the same moisture results as 18-hour drying had given. 

Differences in moisture content from bottle to bottle seem to 

be the principal source of between--laboratory variance in 

the moisture determination and, therefore, also a principal 

factor in the reported between-laboratory variance for LOI. 
tz 

~ a: 

w 

Q. 

t-

::I: 

C!l 

w 

~ 

z 

2.0 

-:. 1.0 w 

a: 

:> 

§ 

Bottle 1 

0.0 --!--

1 2 3 6 7 

Bottle 2 

2 3 6 7 

DAY 

Figure 1. Moisture results after cyclic drying and reabsorption. Days 1, 3, 7: after overnight drying; day 2: after 8 

hours exposure to moist air; and day 6: after 3 days 

exposure to moist air. 

LOI 

In this study, as well as in the original compiled data, 

LOI measured both on an "as received" basis and on a dry 

basis showed considerable variation between bottles (table 

3). This variation suggests that organic matter, as well as 

clay, pyrite, and moisture, are heterogeneously distributed 

between bottles. The compiled total carbon, organic carbon, and C02 results in table 1 do not allow adequate 

homogeneity evaluations, as reported. Bottle-to-bottle 

moisture variation, discussed above, accounts for approximately half the observed LOI between-bottle variance; 

between-bottle variation of organic matter could account 

for most of the remaining variance. CHN data from this 

study appear to confirm this theory. 

Weight gain from pyritic and ferrous iron oxidation 

and possibly from sulfur fixation also accounts for some of 

the observed between-bottle variance in LOI. These aspects 

of between-bottle and between-laboratory variance in LOI 

will be discussed in the next two sections. 

The reactions that potentially occur during ignition 

are summarized in table 4. All are well-documented 

through differential thermal analysis (DT A) studies (Liptay, 

1971; Warne, 1979) to be dependent on ignition temperature. These studies indicate that C02 will not be lost from 

calcite below 800°C; however' magnesite and siderite lose 

C02 at 580 to 690°C and 540 to 620°C, respectively. 

Similarly, pyrite oxidizes to hematite with release of S03 in 

the neighborhood of 580°C. Because DT A studies are 

carried out under very different ignition conditions from 

those for determination of LOI, the reaction temperatures 

found through DT A experiments do not duplicate those for 

ignition reactions; however, DTA results do indicate potential sources of variation in LOI with ignition temperature. 

These factors collectively could explain the observed 

between-laboratory variation that cannot be attributed to 

between-bottle moisture and (or) organic-matter variations. 

One-way anova with temperature as the classification 

variable (table 3) shows the significance of temperature< 

variation. Two-way anova shows the interaction between 

temperature and bottle as a source of variation. That 

interaction is reflected in the nonparallel plots of LOI vs 

ignition temperature for the several bottles included in this 

study (fig. 2). This interaction implies that each of the 

contributions of each of the reactions in table 4 to the 

measured LOI varies somewhat bottle to bottle. 

FeO and S in Ignited Sample 

Total iron reported as Fe20 3 is 9.36±0.22 percent in 

SD0-1; however, based on geochemical and petrological 

evidence (Leventhal and Hosterman, 1982, Frost and others, 1985), little or none of the iron present occurs as ferric 

iron. All iron is instead thought to occur either in pyrite or 

as ferrous iron, occurring mainly in clays, oxides, and to a 

lesser extent in carbonates. Experimentally, both FeO and S 

were determined in samples after ignition. Results of those 

measurements are given in table 5. 

The data show essentially complete oxidation of 

ferrous oxide/carbonate and pyrite at all three ignition 

A Study to Determine Sources of Interlaboratory Variability in Measured Loss on Ignition (LOI) for Devonian Ohio Shale SD0-1 FS 
Table 3. Loss on ignition (in weight percent): Evaluation of bottle and ignitiontemperature differences 

[LOI, loss on ignition; d.f., degrees of freedom; leaders (-), no data] 

Results for lOI as received 

Bottle 550°C, 1 hr 550°C, 18 hr 800°C, 1 hr 1,ooooc, 1 hr 

1 

2 

3 

4 

5 

6 

7 

19.49 

19.97 

19.95 

19.40 

19.49 

19.43 

20.01 

20.89 

21.88 

22.19 

21.04 

8 18.65 

Average 19.25±0.54 

18.85 

19.43±0.53 

20.15 

20.82±0.86 

22.69 

23.22 

23.73 

22.61 

23.72 

21.58 

23.05 

21.58 

23.03±0.59 

F-test data: 

d.f. 2,6 

F 13.3 

Probability LOI 0.007 

same, all bottles 

Fcrit (0.95) 5.14 

3,4 

115.6 

0.001 

4,9 

80.44 

<0.001 

6.59 

Table 4. Reactions during ignition of sample 

Reaction 

Hydrous clays~anhydrous + H20 t 

temperatures (500°C, 800°C, and 1,000°C). This result 

contrasts with the Lechler and Desilets (1987) report that 

oxidation is complete only at 100°C ignition. The weight 

gain of sample during ignition due to iron oxidation, 

therefore, should be the same regardless of ignition temperature. Assuming that all iron in SD0-1 is ferrous initially, 

and that it is totally oxidized to hematite (Fe20 3), that gain 

amounts to 2.25 percent, as shown in table 5. 

Our data also indicate extensive sulfur retention (>20 

percent of initial S) at 500°C ignition, which decreases to 

approximately 10-percent retention at 1 ,000°C ignition. 

Based on the data in table 5, the weight gain of sample will 

be maximum, approximately 2 percent, for ignition at 

500°C, 1.5 percent for ignition at 800°C, and 0. 75 percent 

for ignition at 1 ,000°C. The calculation is given in table 5. 

F6 The USGS Reference Sample Devonian Ohio Shale SD0-1 

Reaction temperatures for specific 

minerals (liptay, 1971; Warne, 1979) 

Siderite: 

Magnesite: 

Calcite: 

Begins at: 

Complete reaction: 

Illite: 

Kaolinite: 

Montmorillonite: 

Essentially complete 

540-620°C 

580-690°C 

>800°C 

580°C 

>1,000°C 

500-550°C 

550-620°C 

700-730°C 

2':1500°C 

CH N in Both "As Received" and Ignited Sample 

Comparison of data for C and H in "as received" and 

ignited sample indicates both complete oxidation of all 

organic matter and nearly complete removal of constitutional water at 500°C. Bottle differences exist for C at both 

the 95-percent and 99-percent confidence levels but are 

less conclusive for H, existing only at the 99-percent 

confidence level (table 6). The data also appear to indicate 

that carbonate remains in 500°C ash but is totally expelled 

as C02 in 800°C ash. 

ANALYTICAL TOTAL 

LOI as measured was shown above to be low by 2.71 

percent (1,000°C) to 4.47 percent (500°C), based on weight 
Table 5. FeO and S in ignited sample residue and weight gain calculations (in weight percent) 

[d.f., degrees of freedom; leaders (-), no data] 

Bottle 

1 

2 

3 

Average 

F -test data: 

d.f. 

F 

Probability S 

same, all bottles 

Fcrit (0.95) 

Oxidation of iron 

Reaction 

Pyritic Fe ~Fe0 

As received 

s 

5.50±0.07 

5.38±0.03 

5.28±0.05 

5.38±0.11 

2,6 

248 

<.001 

5.14 

Analytical data 

500°C 

s FeO 

1.40 0.16 

1.41 .12 

1.60 

Weight gain calculations 

Starting 

weight percent X 

Gravimetric 

factor 

FeO (from pyrite)~Fe 3 

2Fe0 (from clays, etc.)~Fe 3 

4.66 

5.99 

2.41 

55.85+16 

55.85 

2(55.85)+3(16) 

2(55.85+ 16) 

Total gain 

Fixation of sulfur 

Reaction Comment 

Three oxygens for every 

sulfur fixed, or where 

X=Mg, Ca, Fe 

At 550°C ignition 

800°C 

1000°C 

Table 6. CHN results for SD0-1 

[In weight percent; d. f., degree of freedom] 

As received 

After ignition at 

800°C 

s FeO 

0.95 0.08 

.97 

1.00 

Final 

weight percent 

5.99 

6.65 

2.67 

Gravimetric 

factor 

3(16)*S 

32 fix 

(1.5) (1.4) 

(1.5) (1.0) 

(1.5) (0.45) 

After ignition 

Bottle c H N C H N c H 

1,ooooc 

s FeO 

0.44 0.08 

.46 .06 

.44 

Gain in 

weight percent 

1.33 

.66 

.26 

2.25 

Gain in 

weight percent 

N 

1.5*Sfix 

=2.1 

=1.5 

=0.68 

1 

2 

3 

9.92 1.23 0.31 

9.66 1.38 .33 

9.59 1.41 .35 

0.22 0.04 0.06 

.17 .04 .04 

.18 .05 .07 

<0.01 <0.010.05 

<.01 <.01 .06 

<.01 <.01 .06 

Average 

C02 equivalent 

F-test data: 

d.f. 

F 

Probability bottles same 

-----

9.72 1.34 .33 

2,6 

248 5.92 2.66 

<.001 .038 .15 

.187 .043 .057 <.01 <.01 .057 

0.63--0.81 <0.03 

A Study to Determine Sources of Interlaboratory Variability in Measured Loss on Ignition (LOI) for Devonian Ohio Shale SD0-1 F7 
24 

23 

1- 22 

z 

w 

(J 

a: 

w 

a. 

~ 21 (!) 

jjj 

5: 

0 

...J 

20 

19 

18 ~-------------------------------------

500 600 700 800 900 1000 

IGNITION TEMPERATURE, IN oc 

0 Bottle 1 6. Bottle 2 0 Bottle 3 0 Bottle 8 

Figure 2. LOI as a function of temperature, illustrating 

interaction between temperature and bottle components 

of variance. 

gains during ignition due to iron oxidation and sulfur 

fixation that varied as a function of ignition temperature and 

on failure to expel C02 at 500°C. The sum of volatile 

components, based on correction of measured LOI, should 

therefore be 23.92-25.77 percent. The original analytical 

summation of recommended concentrations for (nonvolatile) major rock-forming oxides was calculated having iron 

appropriately included as Fe +2 from pyrite or FeO. That 

summation is 75.81 percent without the volatile components, and 99.73 percent to 101.58 percent including 

volatile components, based on LOI corrections for 500°C 

and 1 ,000°C ignition (table 7). Alternatively, the sum of 

volatile components can be estimated to be 23.16 percent, 

as shown in table 7, leading to a final summation of 98.97 

percent. 

CONCLUSION 

With proper understanding of the components in 

measured LOI, accurate totals of 100±2 percent can be 

achieved for sulfur- and (or) organic-rich samples, of 

which SD0-1 is representative. The acceptability of the 

F8 The USGS Reference Sample Devonian Ohio Shale SD0-1 

Table 7. Alternative estimates of the sum of volatile components 

[Leaders (-), no data] 

Volatile components as corrected 

500°C 800°C 

LOI 19.25 20.83 

so3 in ash 1.40 1.0 

Gain from Fe oxidation 2.26 2.26 

C02 residue 1.01 

Total volatile components 23.92 24.09 

Total oxides* 75.81 75.81 

Analytical summation 99.73 99.90 

Estimate of individual volatiles 

from compilation averages 

Organic=Corgx 1.3 

C02 

H2o+ 

H2os 

Total volatile compoments 

Total oxides* 

Analytical summation 

12.57 

1.01 

2.63 

1.60 

5.35 

23.16 

75.81 

98.97 

1,000°C 

23.06 

.45 

2.26 

25.77 

75.81 

101.58 

*summation includes pyritic iron as Fe +2 , balance of total iron as 

FeO, in weight percent. 

totals does not ensure that the individual recommended 

concentrations are correct but nonetheless adds to our 

confidence in those concentrations. 

REFERENCES 

Abbey, Sidney, 1983, Studies in "Standard Samples" of silicate 

rocks and minerals, 1969-1982: Geological Survey of Canada Paper 83-15, 114 p. 

Frost, J.K., Zierath, D.L., and Shimp, N.F., 1985, Chemical 

Composition and Geochemistry of the new Albany Shale 

Group (Devonian-Mississippian) in Illinois: Illinois State 

Geological Survey Contract/Grant Report 1985-4, 134 p. 

Gladney, E.S., and Roelandts, lwan, 1988, 1987 compilation of 

elemental concentration data for USGS BHV0-1, MAG-1, 

QL0-1, RGM-1, SCo-1, SDC-1, SGR-1, and STM-1: 

Geostandards Newsletter, v. 12, p. 253-362. 

Jackson, L.L., Brown, F.W., and Neil, S.T., 1987, Major and 

minor elements requiring individual determination, classical 

whole rock analysis, and rapid rock analysis, in Baedecker, 

P.A., ed., Methods for geochemical analysis: U.S. Geological Survey Bulletin 1770, p. G1-G23. 

Kane, J.S., Arbogast, B.F., and Leventhal, J.S., 1990, Characterization of Devonian Ohio Shale SD0-1 as a USGS 
geochemical reference sample: Geostandards Newsletter, v. 

14, p. 169-196. 

Lechler, P.J., and Desilets, M.O., 1987, A review of the use of 

loss on ignition as a measure of total volatiles in whole rock 

analysis: Chemical Geology, v. 63, p. 341-344. 

Leco Corporation, 1980. Leco SC-132 sulfur system instruction 

manual 200-192. 

Leventhal, J.S., and Hosterman, J.W., 1982, Chemical and 

mineralogical analysis of Devonian Black Shale samples 

from Martin County, Kentucky; Carroll and Washington Counties, Ohio; Wise County, Virginia; and Overton 

County, Tennessee, USA: Chemical Geology, v. 37, p. 

239-264. 

Liptay, G., ed., 1971, Atlas of thermoanalytical plots: Amsterdam, Hayden and Sons, v. 1-3, p. 116, 161, 162, see 

especially v. 1 , curve 21. 

Perkin Elmer Corporation, 1988. 2400 CHN elemental analyzer 

instruction manual 0993-714 7. 

Potts, P.J., 1987, A handbook of silicate rock analysis: Blackie, 

Glasgow. 

Shapiro, Leonard, and Brannock, W.W., 1962, Rapid analysis of 

silicate, carbonate, and phosphate rocks: U.S. Geological 

Survey Bulletin 1144A, 56 p. 

Warne, S. St. J., 1979, Differential thermal analysis of coal 

minerals in Analytical methods for coal and coal products, v. 

3, Academic Press, p. 447-447. 

A Study to Determine Sources of Interlaboratory Variability in Measured Loss on Ignition (LOI) for Devonian Ohio Shale SD0-1 F9 

Chapter G 

Analysis of SD0-1 Pressed Powder Pellets 

by X-ray Fluorescence-A Note of Caution 

By OTTO C. KOPP and FRANCIS C. FURMAN 

U.S. GEOLOGICAL SURVEY BULLETIN 2046 

THE USGS REFERENCE SAMPLE DEVONIAN OHIO SHALE SD0-1 

Analysis of SD0-1 Pressed Powder Pellets by X-ray 

Fluorescence-A Note of Caution 

By Otto C. Kopp and Francis C. Furman 1 

SD0-1 is an organic-rich shale relatively high in 

sulfur. Caution should be used in analyzing this shale by 

X-ray fluorescence (XRF) using a pressed-pellet technique, 

such as described by Wheeler ( 1984). Most available 

standards, used to generate the calibration curves and to 

establish corrections for any matrix effects encountered in 

the analysis, contain lower concentrations of sulfur and 

organic matter than SD0-1 and, therefore, have matrix 

characteristics quite different from SD0-1. 

We attempted to analyze SD0-1 using our standard 

procedures. Representative splits were air-dried at 105°C 

for 1 hour and ground in a swing mill ("shatterbox") for 6 

minutes; the pellets were pressed at 30,000 psi for 1 minute. 

The concentrations for most elements did not agree with the 

recommended values for SD0-1 (Kane and others, 1990). 

After considering several sources of error, we concluded 

that our results were rendered invalid primarily by the high 

concentrations of organic matter and sulfur in SD0-1. Our 

analytical protocol is based on standard reference materials 

that are low in organic matter and sulfur. The maximum 

organic carbon concentration in our standards is unknown 

while the maximum sulfur concentraztion is 1. 89 percent. 

These concentrations are 9.6 percent Corg and 5.35 percent 

Sin SD0-1. 

Perhaps we had become complacent because our 

analytical protocol for clays, shales, and soils had performed so well over a period of several years. Only when 

the interelement correction steps were reexamined did we 

realize the magnitude of the errors that could be introduced. 

Although the use of elements such as sulfur to make 

interelement corrections for major elements may seem 

unusual, the presence of sulfur reflects matrix effects that 

Manuscript approved for publication September 15, 1992. 1 University of Tennessee 

can enhance (or absorb) some of the secondary X-rays 

generated for other elements. 

Hence, a word of caution is advisable to all who use 

pressed pellets to perform XRF analyses of atypical samples 

such as SD0-1. Results are questionable if the net intensities or calculated concentrations for any elements, and 

especially those elements used in the matrix correction 

steps, fall outside the ranges of the standards used in 

generating the protocol. Information about the reference 

standards and interelement correction steps, possibly 

unknown to most users, can be critical to analytical accuracy. 

Matrix effects can be reduced by analyzing samples 

fused with a flux such as lithium tetraborate (for example, 

Spies and others, chap. B, this vol.). However, the fusion 

technique is more time-consuming and costly than preparing pellets; and the addition of a flux reduces the concentrations of trace elements that might be determined simultaneously, making their determination less precise or even 

diluting them to concentrations below their detection limits. 

The problem will ultimately be resolved when new 

standards with high sulfur concentrations and organic-rich 

matrices (such as SD0-1) are added to the analytical 

protocol. 

REFERENCES 

Kane, J.S., Arbogast, Belinda, and Leventhal, Joel, 1990, Characterization of Devonian Ohio Shale SD0-1 as a USGS 

Geochemical reference sample, Geostandards Newsletter, 

14:169-196. 

Wheeler, B.D., 1984, Analysis of rocks and minerals using 

energy dispersive X-ray fluorescence: XRF Note XRF-4, 

EG&G ORTEC, Oak Ridge, Tenn., and Abstract, 1984 

GEOEXPO: Beijing, China, August 1-10, 1984.50. 

Analysis of SD0-1 Pressed Powder Pellets by X-ray Fluorescence-A Note of Caution Gl 





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Water-Supply Reports and Maps For (State)," may be purchased by 

mail and over the counter in paperback booklet form only. 

"Price and Availability List of U.S. Geological Survey 

Publications," issued annually, is available free of charge in paperba~k 

booklet form only. 

Selected copies of a monthly catalog "New Publications of t'-~ 

U.S. Geological Survey" are available free of charge by mail or mqy 

be obtained over the counter in paperback booklet form only. Thc"e 

wishing a free subscription to the monthly catalog "New Publications of 

the U.S. Geological Survey" should write to the U.S. Geological 

Survey, 582 National Center, Reston, VA 22092. 

Note.- Prices of Government publications listed in olcter 

catalogs, announcements, and publications may be incorre~t. 

Therefore, the prices charged may differ from the prices in catalogs, 

announcements, and publications. 
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