Developments in 

Mineral Deposit Modeling 
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• 

• 

• 
Developments in 

Mineral Deposit Modeling 

JAMES D. BLISS, Editor 

U.S. GEOLOGICAL SURVEY BULLETIN 2004 

• 
U.S. DEPARTMENT OF THE INTERIOR 

MANUEL LUJAN, JR., 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, WASHINGTON : 1992 

For sale by the 

Books and Open-File Reports Section 

U.S. Geological Survey 

Federal Center, Box 25425 

Denver, CO 80225 

Library of Congress Cataloging-in-Publication Data 

Developments in mineral deposits modeling I james D. Bliss, editor. 

p. em. - (U.S. Geological Survey bulletin ; 2004) 

Includes bibliographical references. 

Supt. of Docs. no. : I 19.3:2004 

1. Ore deposits. 2. Mines and mineral resources. I. Bliss, 

james D. II. Series. 

QE75.B9 no. 2004 557.3 S-dc20 91--40084 

[TN263] [622'1] CIP 
',~') 

•• 

CONTENTS 

Introduction and overview of mineral deposit modeling, by Dan L. Mosier and 

James D. Bliss 1 

Numerical mineral deposit models, by Richard B. McCammon 6 

DEPOSIT MODELS 

lld 

19c 

25a 

26a 

28a.l 

32e 

34f 

36a.l 

38g 

Descriptive model of thorium-rare-earth veins, by Mortimer H. Staatz 13 

Grade and tonnage model of thorium-rare-earth veins, by James D. Bliss 16 

Descriptive model of distal disseminated Ag-Au, by Dennis P. Cox 19 

Grade and tonnage model of distal disseminated Ag-Au, by Dennis P. Cox and 

Donald A. Singer 20 

Grade and tonnage model of hot-spring Au-Ag, by Byron R. Berger and 

Donald A. Singer 23 

Grade and tonnage model of sediment-hosted Au, by Dan L. Mosier, 

Donald A. Singer, William C. Bagby, and W. David Menzie 26 

Grade and tonnage model of Sierran kuroko deposits, 

by Donald A. Singer 29 

Descriptive model of solution-collapse breccia pipe uranium deposits, 

by Warren I. Finch 33 

Grade and tonnage model of solution-collapse breccia pipe uranium deposits, 

by Warren I. Finch, Charles T. Pierson, and Hoyt B. Sutphin 36 

Descriptive model of oolitic ironstones, by J.B. Maynard and 

F.B. VanHouten 39 

Grade and tonnage model of oolitic ironstones, by Greta J. Orris 41 

Grade and tonnage model of Chugach-type low-sulfide Au-quartz veins, by 

James D. Bliss 44 

Descriptive model of laterite-saprolite Au, by Gregory E. McKelvey 47 

Grade and tonnage model of laterite-saprolite Au, by James D. Bliss 50 

Preliminary descriptive deposit model for detachment-fault-related mineralization, by 

Keith R. Long 52 

40a Descriptive model of detachment-fault-related polymetalic deposits, 

by Keith R. Long 57 

References cited 59 

APPENDIXES 

A. 

B. 

c. 

D. 

E. 

Classification of deposit models by lithologic-tectonic environment 63 

Locality abbreviations 64 

Taxonomy used to define the attributes of numerical mineral deposit 

models 64 

Worksheets for numerical mineral deposit models 79 

Minerals identified in solution-collapse breccia pipe uranium 

deposits 168 

Contents Ill 
IV Contents 

FIGURES 

1. Sketch of idealized model showing relationship of thorium-rare-earth veins to 

alkalic rocks and carbonatites 15 

2-19. Graphs showing: 

2. Tonnages of thorium-rare-earth veins 17 

3. Thorium-oxide grades of thorium-rare-earth veins 17 

4. Rare-earth-oxide grades of thorium-rare-earth veins 18 

5. Tonnages of distal disseminated Ag-Au deposits 21 

6. Gold grades of distal disseminated Ag-Au deposits 21 

7. Silver grades of distal disseminated Ag-Au deposits 22 

8. Tonnages of hot-spring Au-Ag deposits 24 

9. Gold grades of hot-spring Au-Ag deposits 24 

10. Silver grades of hot-spring Au-Ag deposits 25 

11. Tonnages of sediment-hosted Au deposits 27 

12. Gold grades of sediment-hosted Au deposits 28 

13. Silver grades of sediment-hosted Au deposits 28 

14. Tonnages of Sierran kuroko deposits 30 

15. Copper grades of Sierran kuroko deposits 30 

16. Zinc grades of Sierran kuroko deposits 31 

17. Lead grades of Sierran kuroko deposits 31 

18. Gold grades of Sierran kuroko deposits 32 

19. Silver grades of Sierran kuroko deposits 32 

20 Schematic cross section of a solution-collapse breccia pipe in the Grand Canyon 

region, showing the general distribution of uranium ore within the pipe 35 

21. Graph showing tonnages of solution-collapse breccia pipe uranium 

deposits 36 

22. Graph showing uranium-oxide grades of solution-collapse breccia pipe uranium 

deposits 37 

23. Scatter plot of logarithms of uranium-oxide grade vs. tonnage of uranium 

ore 38 

24. Diagram of generalized stratigraphic model for oolitic ironstones 40 

25-31. Graphs showing: 

25. Tonnages of oolitic ironstone deposits 41 

26. Iron grades of oolitic ironstone deposits 42 

27. Silica grades of oolitic ironstone deposits 42 

28. Phosphate grades of oolitic ironstone deposits 43 

29. Tonnages of Chugach-type low-sulfide Au-quartz vein deposits 45 

30. Gold grades of Chugach-type low-sulfide Au-quartz vein deposits 45 

31. Silver grades of Chugach-type low-sulfide Au-quartz vein deposits 46 

32. Sketch of idealized cross section of laterite-saprolite Au deposit 47 

33. Graph showing tonnages of laterite-saprolite Au deposits 50 

34. Graph showing gold grades of laterite-saprolite Au deposits 51 

35. Location map of major detachment faults and detachment-fault-related mineral 

deposits in Arizona, southeastern California, and southernmost Nevada 53 

36. Schematic diagram showing structural position of detachment-fault-related 

polymetallic mineralization, Ba-F-Mn veins, and lacustrine 

manganese mineralization in detachment-faulted terranes 54 
TABLES 

1. Quantization levels for presence/absence of particular mineral deposit 7 

2. Quantization levels and associated scores for mineral deposit models 8 

3. Worksheet for numerical model of Sn greisen deposits 10 

4. Comparison of classification between Prospector II and panel of geologists 

using the Cox-Singer deposit classification for 124 metalliferous lode deposits 

in Alaska (Nokleberg and others, 1987) 11 

5. Grades and tonnages of distal disseminated Ag-Au deposits 20 

6. Grades and tonnages of hot-spring Au-Ag deposits 23 

7. Grades and tonnages of sediment-hosted Au deposits 27 

8. Grades and tonnages of Sierran kuroko deposits 29 

9. Summary statistics of chemical analyses of one selected sample from each of 

the five solution-collapse breccia pipe uranium deposits 38 

10. Grades and tonnages for detachment-fault-related polymetallic deposits 56 

Contents V 

Introduction and Overview of 

Mineral Deposit Modeling 

By Dan L. Mosier and James D. Bliss 

INTRODUcriON 

Activities in mineral deposit modeling have continued to develop on several fronts since the publication of 

"Mineral Deposit Models/' edited by Cox and Singer 

(1986). That bulletin is a collection of 87 descriptive deposit models and 60 grade and tonnage models prepared 

by many authors both from within and outside of the U.S. 

Geological Survey. The present bulletin continues that effort with the addition of new or revised models. Before 

these models are introduced, a review of modeling as used 

here is provided as well as an overview of mineral deposit 

modeling since the publication of Cox and Singer (1986). 

EXPLANATION OF DESCRIPTIVE AND GRADE 

AND TONNAGE MODELS 

A general definition of a mineral deposit model as 

found in Cox and Singer (1986, p. 2) is "the systematically 

arranged information describing the essential attributes 

(properties) of a class of mineral deposits. The model may 

be empirical (descriptive), in which instance the various 

attributes are recognized as essential even though their relationships are unknown; or it may be theoretical (genetic), 

in which instance the attributes are interrelated through 

some fundamental concept." 

With a descriptive model in hand, member deposits 

can be recognized and their size and grades can be used to 

develop a grade and tonnage model. Ideally, the data 

should be the estimated premining tonnages and grades. 

Estimates should be for the tonnage at the lowest cutoff 

grades. The grade and tonnage model is presented in a 

graphical format in order to make it easy to display the 

data and to compare this type of deposit with other deposit 

types (Cox and Singer, 1986). The plots (figs. 2-19, 

21, 22, 25-34) show either grade or tonnage on the horizontal axis, whereas the vertical axis is always the cumulaManuscript approved for publication, July 25, 1991. 

tive proportion of deposits. The units are all metric, and a 

logarithmic scale is used for tonnage and most grades. 

Each dot represents an individual deposit, and the deposits 

are cumulated in ascending grade or tonnage. Owing to 

limitations in the plot routine, a point will not be shown 

on the plot if it has exactly the same value as the vertical 

axis (for example, the Keystone-Union deposit is not displayed in figure 12). On rare occasions, values less than 

the value of the vertical axis are not shown as well (for 

example, Hog Ranch is not displayed in figure 16). 

Smoothed curves, representing percentiles of a lognormal 

distribution that has the same mean and standard deviation 

as the observed data, are plotted through the points. Intercepts for the 90th, 50th, and lOth percentiles of the lognormal distributions are constructed. 

OVERVIEW OF PAPERS ON DEPOSIT 

MODELING 

A number of papers on deposit modeling and support data have been published in various places since 

1986. These papers focus on descriptive deposit models 

and (or) grade and tonnage models that are useful for resource assessments. Some of the papers document the 

models originally published in Cox and Singer (1986), 

others attempt to improve the models' applicability in resource assessments, and still others present new deposit 

models. The following overview is presented chronologically by type of study. Model numbers shown in parentheses follow the format used in Cox and Singer (1986), with 

some modifications. 

Several papers not cited in Cox and Singer (1986) 

document the data used in some of the grade and tonnage 

models. Orris (1985) provided data for 93 bedded barite 

deposits (No. 31b), of which less than 30 had grade and 

tonnage information. Additional tabulated data for each 

deposit include volume of deposit, associated minerals, 

host formation, host age, host lithology, and references. 

Orris and Bliss (1985) provided data for 330 gold placers 

(No. 39a). The data for each deposit include placer type, 

mining method(s), production history, bedrock source, and 
references. Bagby and Berger (1986) presented data for 31 

of the deposits used in the grade and tonnage model for 

carbonate-hosted Au-Ag (No. 26a) and discussed the geologic characteristics of the deposit type, which (in order to 

accommodate the noncarbonate host rocks) they called the 

sediment-hosted, disseminated precious-metal deposits. A 

number of tables provide information on host rocks, igneous rocks, structure, mineralization age, alteration, ore 

bodies (form, mineralogy, gold or silver site, veins), traceelement geochemistry, tonnage, grades, and references for 

selected deposits. Also included are plots of trace-element 

variations, sulfur isotopic variation in sulfides and barite, 

gold grade versus tonnage, and cumulative frequency distributions of tonnages and grades. Bliss and Jones (1988) 

provided data for 357 deposits used to develop the grade 

and tonnage model for low-sulfide Au-quartz veins (No. 

36a). Tabulated data for each deposit include tonnage, 

grades, mineralogy, and references. This paper also evaluated the frequency of occurrence, order of abundance, and 

assemblages of ore minerals, and displayed the results in 

tables and pie diagrams. 

Grade and tonnage models can provide insight into 

geologic processes. A paper by Mosier and others (1986) 

documented three types of epithermal gold-quartz-adularia 

deposits, based on the types of basement rocks underlying 

the host volcanic pile. The Sado type (No. 25d) occurs 

over an igneous-dominant basement, the Comstock type 

(No. 25c) over a sedimentary-dominant basement, and the 

Creede type (No. 25b) over a saline-carbonate-dominant 

basement. Each type has different tonnages and grades, 

particularly among the base metals. These models indicate 

that basement rocks probably influence the character of the 

ore fluids. Grade and tonnage models are shown for the 

three deposit types. Tabulated data for each district include 

tonnage, grades, basement rocks, and references. A study 

by Page and others (1986) examined the platinum-group 

element values of 250 deposits used in the grade and tonnage model for minor podiform chromite deposits (No. 8a) 

to test for homogeneity of platinum-group elements within 

the deposit type. Analysis of variance of platinum-group 

element content demonstrated that deposits within terranes 

were not significantly different. Relatively small but significant differences in the combined medians for Ir, Ru, 

Rh, and Pt exist (at the 1 percent level) among terranes, 

but the reasons for these differences are not clear. Also, it 

was discovered that the platinum-group element abundances of minor podiform chromite deposits are similar to 

those of major podiform chromite deposits (No. 8b). A 

part of the analysis of platinum-group elements is tabulated, and grade models for individual platinum-group elements are shown. 

There are three new descriptive deposit models 

based on one or two examples. These new models have 

not been included in this bulletin because they do not have 

2 

associated grade and tonnage models. Cox and Rytuba 

(1987) developed a descriptive model for Lihir Island gold 

(No. 25), a gold deposit occurring in the root of a volcanic 

center. This deposit, in Papua New Guinea, is the only 

known example of its type. Tosdal and Smith (1987) developed two descriptive models for deposits in regionally 

metamorphosed eugeosynclinal rocks. (The model numbers assigned to these models should have been 36 rather 

than 37, in that they are not hosted in metasedimentary 

rocks.) First, the gneiss-hosted gold model (No. 37c) is 

based on the Tumco mine group and American Girl-Padre 

y Madre mines in the Cargo Muchaco Mountains, southeastern California. This deposit type either occurs in lenticular bodies of biotite-magnetite-quartz gneiss of volcanic or granitic origin, subparallel to the gneissic foliation, or 

is associated with low-angle ductile shear zones. Second, 

the gneiss-hosted epithermal gold model (37d) is based on 

the Mesquite mine, southern California, which occurs in 

breccia fillings, fracture fillings, and high-angle veins that 

cut subhorizontal amphibolite-facies metavolcanic gneiss 

and plutonic gneiss. The Mesquite deposit is similar to epithermal quartz-adularia-gold vein deposits (Sado type?), 

except that it is hosted in metaigneous rocks-this raises 

the question of whether or not it should be treated as another type of deposit. 

Attempts to distinguish subtypes within existing deposit models have been carried out in several papers. 

Heald and others (1987) successfully distinguished two 

types of volcanic-hosted epithermal precious- and basemetal deposits through a detailed examination of the characteristics of 17 well-documented districts. These characteristics include the ore, gangue, and alteration mineral 

assemblages; the spatial and temporal distributions of mineral assemblages; the host-rock composition; the age relations between ore deposition and emplacement of the host 

rock; the size of the district; the temperatures of mineral 

deposition; the chemical composition and origin of the fluids; the paleodepth estimates; and the regional geologic 

setting. Differences in many of these characteristics were 

documented in the two major types designated the acidsulfate type and the adularia-sericite type. It was found 

that the two most important factors for distinguishing these 

types are (1) the vein and alteration mineral assemblages 

and (2) the age relations between ore deposition and emplacement of the host rock. Bliss and others (1987) examined gold grades and volumes to distinguish among gold 

placer types but found that they could not distinguish most 

types of gold placers, except for the alluvial-plain and fan 

placers. However, when these data were coupled with mining methods, estimates could be made of the amount of 

gold remaining when a placer mine changes from smallvolume mining (such as panning, sluicing, or drift mining) 

to large-volume mining (such as dredging or hydraulic 

mining). New descriptive and grade and tonnage models 
for two subtypes of Au-bearing skarn deposits were designated Au skarn and byproduct Au skarn (Orris and others, 

1987; Theodore and others, 1990). Although the two subtypes do not differ in geologic characteristics or tonnages, 

there are significant differences in the median gold and silver grades. Tabulated data which are largely overlapping 

can be found in both Orris and others (1987) and Theodore 

and others (1990). Data tables give name, location (mining 

district), formation age/name, igneous rocks, age, ore minerals, gangue minerals, ore control, tonnage, gold grade, 

silver grade, base metal grades, comments and references. 

Cox and Singer (1988) examined the distribution of gold 

in three types of porphyry copper deposits designated as 

porphyry copper-gold (No. 20c ), porphyry copper-goldmolybdenum (No. 17), and porphyry copper-molybdenum 

(No. 21a). This paper defines the three types of porphyry 

copper deposit models used in Cox and Singer (1986). It 

was concluded that gold content alone could not define 

porphyry copper-gold systems, but that the three types 

differed significantly in Cu-Mo-Au content, magnetite 

content, deposit morphology, depth of emplacement, 

and tonnage. Mosier and Page (1988) distinguished among 

four subtypes of volcanogenic manganese deposits (No. 

24c) based on tectonic environments. These subtypes are 

supported by differences in tonnage, grades, volume, lithology, mineralogy, and deposit morphology. The new modelscalled Franciscan (No. 24c.1), Cuban (No. 24c.2), Olympic Peninsula (No. 24c.3), and Cyprus (No. 24c.4)-each 

have individual descriptive and grade and tonnage models 

and mineral-deposit density values. 

Berger and Singer (1987) developed a new grade 

and tonnage model for hot-spring gold-silver deposits (No. 

25a) based on 10 deposits in Nevada and California. 

The importance of industrial minerals in economic 

development has been long recognized in national and international assessments and commonly far exceeds that of 

fuels and metals. However, they usually receive only a 

passing reference. This is because, in part, they cannot always be modeled using standard grade-tonnage models. 

Orris and Bliss (1989) took a step in resolving this impasse by formally defining three new model types for describing industrial mineral deposits. These include (1) the 

contained-material model applicable to commodities where 

the material must meet a minimum level of purity (for example, feldspars, travertine); (2) the impurity model for 

commodities where the distribution of impurities affects 

utilization (for example, iron or aluminum in glass sand); 

and (3) the deposit-specific model applicable to commodities that are unique (for example, the distribution of the 

proportion of gem-quality diamonds, and the average diamond size in diamond kimberlite pipes). Descriptive models of 22 industrial mineral deposit types prepared by 13 

contributors can be found in a report edited by Orris and 

Bliss (1991). Sutphin and Bliss (1990) compared amorphous and disseminated deposit types using graphite grade, 

tonnage, and contained carbon. While differences are 

clearly present in the carbon grade and tonnage between 

the two types, this was not the case for contained carbon. 

A graphic method was develop by Bliss and others 

(1990) to show how tonnage data can be used to guide in 

the selection among the 71 deposit types (with grade and 

tonnage models) during the search for deposits amenable 

to small-scale mining. McKelvey and Bliss (1991) compared the contained copper, lead, zinc, gold, and (or) silver 

of a median deposit for all deposit types having grade and 

tonnage models with the 1989 world production of copper, 

lead, zinc, gold, and silver. This work shows the importance of porphyry deposit types as a source of most of 

these metals. 

NEW DEVELOPMENTS IN DEPOSIT MODELING 

This volume will be one of several pertaining to developments in deposit modeling. Future volumes will include studies on predictive resource assessments, exploration modeling, and spatial modeling. Here, we present six 

new descriptive models, nine new or revised grade and 

tonnage models, and a numerical method of matching mineral deposits to deposit models. New descriptive models 

were developed for thorium-rare-earth veins (No. 11d), 

distal disseminated Ag-Au (No. 19c), solution-collapse 

breccia pipe uranium deposits (No. 32e), oolitic ironstones 

(No. 34t), laterite-saprolite Au (No. 38g), and detachmentfault base and preciousmetals (No. 40a). New grade and 

tonnage models include thorium-rare-earth veins (No. 

11d), distal disseminated Ag-Au (No. 19c), Sierran kuroko 

(28a.1), solution-collapse breccia pipe uranium deposits 

(No. 32e), oolitic ironstones (No. 34t), Chugach-type lowsulfide Au-quartz veins (36a.1), and laterite-saprolite Au 

(No. 38g). Revised existing grade and tonnage models include hot-spring Au-Ag (No. 25a) and sediment-hosted Au 

(No. 26a). The principal use of grade and tonnage models 

is for making quantitati~e mineral resource assessments. A 

recent example can be found in a paper by Reed and others ( 1989) for the Seward Peninsula, Alaska. They used 

grade and tonnage models for So skarns (Menzie and 

Reed, 1986a), replacement So (Menzie and Reed, 1986b), 

So veins (Menzie and Reed, 1986c), and So greisen (Menzie and Reed, 1986d). These models, together with estimates of the number of undiscovered deposits, allow computer simulations to be made that estimate the amount of 

So in undiscovered deposits of the Seward Peninsula. 

A new development by R.B. McCammon is the 

numerical characterization of deposit models. This 

method can be used to assign the appropriate deposit 

type to a target mineral deposit, permitting a quantitative matching of the description of a mineral deposit to 

3 
one or more descriptive models. To facilitate the scoring 

used to do this, worksheets are provided for each of the 

descriptive models found in Cox and Singer (1986). 

The descriptive model of thorium-rare-earth veins 

(No. 11d), by Mortimer Staatz, is based on data from 

North American deposits. The grade and tonnage model of 

thorium-rare-earth veins by J.D. Bliss is different from 

those developed for most other deposit types modeled to 

date in that none of the thorium-rare-earth deposits have 

been mined extensively. Instead of using grades and tonnages from production plus reserves plus resources, the 

model is based on estimates of size of unworked veins and 

the median values of rock analyses. The grade and tonnage 

model is based on 28 deposits in the United States and one 

in Mexico. 

The descriptive model of distal disseminated Ag-Au 

(No. 19c) by D.P. Cox, was developed during the analysis 

of Nevada's resources project for deposits that (1) are richer in Ag relative to Au, (2) contain Zn, Pb, Cu, and Mn, 

(3) occur near igneous intrusions, and (4) are distally associated with skarns and polymetallic veins and replacements. Some of these deposits were formerly classified as 

carbonate-hosted Au-Ag deposits (No. 26a; Berger, 

1986a). The grade and tonnage model, by D.P. Cox and 

D.A. Singer, is based on data for 10 deposits from the 

United States, Mexico, and Peru. 

The grade and tonnage model of hot-spring Au-Ag 

(No. 25a), by B.R. Berger and D.A. Singer, is a revision 

of an earlier model by Berger and Singer (1987). It is in 

response to the availability of grade and tonnage data for 

more deposits and of revised data for others. 

The grade and tonnage model of sediment-hosted Au 

(No. 26a), by D.L. Mosier, D.A. Singer, W.C. Bagby, and 

W.D. Menzie, is a revision of an earlier model by Bagby 

and others (1986). It is in response to the availability of 

grade and tonnage data for more deposits and to a new 

definition for a deposit, which combined or separated 

some deposits. The result of this new descriptive definition 

is that some deposits included in the earlier model have 

been reassigned to distal disseminated Ag-Au (No. 19c) by 

D.P. Cox. 

The grade and tonnage model of Sierran kuroko deposits (No. 28a.1), by D.A. Singer, was developed because 

Triassic or Jurassic deposits of the kuroko massive sulfide 

(No. 28a) in North America and, perhaps, South America 

are significantly smaller than the worldwide kuroko group 

as described by Singer and Mosier (1986). 

The descriptive model of solution-collapse breccia 

pipe uranium deposits (No. 32e), by W.I. Finch, is based 

on deposits from the Colorado Plateau of Arizona. This 

deposit type is most likely an important future source of 

uranium. The grade and tonnage model, by W.I. Finch, 

C.T. Pierson, and H.B. Sutphin, is developed from data on 

eight deposits in Arizona. The model is atypical in that the 

4 

deposit tonnages have a very narrow range and the lognormal distribution was rejected. This is also true for uranium 

oxide grades. 

The descriptive model of oolitic ironstones (No. 

34t), by J.B. Maynard and F.B. Van Routon, is an important addition to the two existing descriptive models for 

iron deposits including Superior Fe (Cannon, 1986b) and 

Algoma Fe (Cannon, 1986a). The grade and tonnage model of oolitic ironstones, by G.J. Orris, is based on 40 deposits from North and South America, Europe, and China. 

The grade and tonnage model of Chugach-type lowsulfide Au-quartz veins (No. 36a.l), by J.D. Bliss, was developed because low-sulfide Au-quartz veins in and adjacent to the Chugach National Forest, Alaska, are 

significantly smaller and have lower Au grades than the 

low-sulfide Au-quartz veins (No. 36a) elsewhere in the 

world (modeled by Bliss, 1986). This model and the previous one developed for kuroko massive sulfide exemplify 

the flexibility of grade and tonnage models in conforming 

to a specific geologic criterion that is observed but for 

which the reasons are not yet clear. These and other identified subtypes represent opportunities to identify either economic and (or) geologic factors causing these differences. 

Au placers have been classified using various criteria, including types and modes of transport. Placers are 

identified as "alluvial" when concentration has occurred in 

streams and rivers, "colluvial" when Au has been transported with surface material by downhill creep away from 

the bedrock source, and "eluvial" when a deposit develops 

in situ over or adjacent to the bedrock sources (Boyle, 

1979). The descriptive model of laterite-saprolite Au (No. 

38g), by G.E. McKelvey, is of the latter type, but it is a 

type that develops primarily from chemical rather than 

physical processes. Because these deposits develop chemically, they have been classified here as a residual rather 

than a depositional type of deposit. This continuum between the two types is an enigma in classification schemes 

and should really be represented by both types-hence its 

inclusion in parentheses in the depositional type of deposit 

(see app. A). Au is transported in water under near-surface 

temperature and pressure conditions, and deposition appears to be controlled by ground-water levels in areas that 

have or have had tropical and subtropical climate conditions. The ubiquitous nature and the hydrogeologic and paleoclimatic constraints of this deposit type could affect the 

applicability of the model (depending, of course, on the 

level of information available) in resource assessments. 

The deposits used in the grade and tonnage model of laterite-saprolite Au, by J.D. Bliss, are based on the model 

(No. 38g) by G.E. McKelvey. The grade and tonnage 

model is developed from data on nine, some which are 

poorly defined, deposits from Guyana, Western Australia, 

and Surname. Like the thorium-rare-earth model (No. 

lld), these deposits have yet to be worked extensively. 
The preliminary descriptive model of detachmentfault-related polymetallic deposits (No. 40a), by K.R. 

Long, is part of the continued effort to effectively describe this emerging deposit type(s). The model is preceded by a paper giving an evaluation of available descriptive and grade-tonnage data, including a list of 

distinguishing characteristics of detachment-fault-related mineralization. Also given is a list of deposit types 

commonly confused with detachment-fault-related mineralization. The descriptive model of gold on flat faults 

(No. 37b) by Bouley (1986) is an earlier model for this 

deposit type. An important revision of this model, using 

lithologic-tectonic environment criteria of Cox and 

Singer (1986, table 1), is its reclassification into the 

new categories of "Regional Geologic Structures" and 

"Extended Terranes" (see app. A). 

Each of the grade and tonnage models presented 

in this bulletin is accompanied by a list of the deposits, 

locations, and, in some cases, the grade and tonnage 

data. The location is shown by an abbreviated form that 

identifies efther the country or the country plus a state 

or province. A list of abbreviations is provided in appendix B. 

Descriptive and grade and tonnage models are 

useful in mineral resource assessments, but, as demonstrated in these studies, they may have wider applications. Not only do these models help to define the 

many deposit types present, but they also help to decipher the complexities of mineral concentrations and 

provide insight on the genetic or geologic processes responsible for their formation. 

5 
Numerical Mineral Deposit Models 

By Richard B. McCammon 

INTRODUCTION 

The numerical mineral deposit models described in 

this paper are a part of a continuing effort to develop more 

quantitative approaches to assessing undiscovered mineral 

resources in graphically defined areas. These models have 

their origin in the descriptive mineral deposit models of 

Cox and Singer (1986). As defined by Cox and Singer, 

descriptive mineral deposit models represent a systematic 

arrangement of information summarizing the essential attributes (properties) of a class of mineral deposits. Such 

information is available usually in carrying out regional 

mineral resource assessments (Shawe, 1981). Descriptive 

mineral deposit models provide the geologist with a link 

between deposit types and geologic environments. Establishing links within a given area is the first step of the 

three-step assessment process described by Singer and Ovenshine (1979). The definition of this step is the delineation of areas according to the types of deposits that the 

geology will permit. 

This decision as to which types of deposits are permitted by the geology of an area is subjective. The decision is dependent almost entirely on the experience of the 

geologist performing the assessment. The more experienced the geologist, the more likely the models that are 

selected will be the right ones. Consequently, a team approach involving geologists having knowledge about different deposit models will ensure that a wide range of possibilities will be considered. The best approach is to give 

the team access to geologists with expert knowledge about 

the deposit models being considered. The idea of giving 

the geologist access to experts gave rise to Prospector, an 

expert system developed during the mid-1970's to aid the 

geologist in the search for hidden deposits (Duda, 1980). 

Expert systems are computer programs that achieve competence in performing specialized tasks by reasoning about 

the task and the task domain (Feigenbaum and others, 

1988). During the years of its development, which lasted 

until 1983, Prospector was regarded as a serious attempt to 

model the decision-making process involved in the application of deposit models in mineral exploration. 

Since 1983, much has changed. Prospector II, the 

successor to Prospector, has been developed at the U.S. 

Geological Survey (McCammon, 1989). Two major devel6 

opments have included (1) the format used to represent deposit models, and (2) the algorithm used to classify mineral occurrences, prospects, and deposits. These developments were necessary in order to (1) acquire a more 

comprehensive, economical, and adaptable deposit model 

format, and (2) accommodate changes in the use of descriptive mineral deposit models in regional mineral resource assessments (Singer and Cox, 1988). Numerical 

mineral deposit models have emerged as a result of these 

developments. 

NUMERICAL MINERAL DEPOSIT MODELS 

Numerical models differ from descriptive models in 

that numerical scores are associated with each model. A 

maximum score is obtained when the geologist concludes 

that all of the attributes of a particular model are present. 

However, maximum scores for different models differ. 

The reason is that models are made up of different attributes. In particular, two scores--one that is positive, and 

one that is negative-are associated with each of the attributes. A positive score reflects the degree to which a 

model is suggested by the presence of a particular attribute. A negative score reflects the degree to which a 

model is negated when a particular attribute is absent. If, 

on the other hand, the absence of an attribute is suggestive 

of a model, a positive score is associated with its absence, 

and a negative score is associated with its presence. Consequently, the states of presence and absence correspond, 

respectively, to the conditions of sufficiency and necessity 

in Prospector (Duda, 1980). 

The attributes of numerical models are grouped into 

headings similar to those of descriptive models. The current headings in the numerical models are the "AgeRange," "RockTypes," "TextureStructure," "Alteration," 

"Mineralogy," "GeochemicalSignature," "GeophysicalSignature," and "AssociatedDeposits." In an attempt to represent the linkages within these attributes, a taxonomy has 

been created that facilitates these linkages. For example, 

under RockTypes, "Granite" is defined as a "kind-of' Felsic-plutonic RockType, which is a "kind-of' Plutonic 

RockType, which is a "kind-of' Igneous RockType. Thus, 

numerical models are characterized by generalized at-
tributes as well as by specific attributes. This "kind-of' 

characterization aids greatly in limiting the number of 

models considered at any one time. The taxonomy that defines the attributes of the numerical models described in 

this paper is given in appendix C. 

Virtually all of the terms listed in the taxonomy in 

appendix C appear as attributes in one or more of the descriptive models in Cox and Singer (1986). In creating the 

numerical models, the decision was made to preserve to 

the maximum extent possible the terminology used by the 

authors who contributed the descriptive models. As a result, the taxonomy does not contain terms not found in the 

descriptive models. Thus, the taxonomy is not a glossary 

of geology, but rather a glossary of terms used in the descriptive models. 

Not all of the headings contained in the descriptive 

models are included in the numerical models. The reason 

is that it is not yet possible to define a taxonomy and to 

assign positive and negative scores for attributes that relate 

to headings such as "TectonicSetting," "DepositionalEnvironment," and "OreControls". Despite these shortcomings, 

the numerical models described in this paper offer a further means of quantifying the decision as to which mineral 

deposit models are permitted by the information collected 

in regional mineral resource assessments. 

WEIGHTING OF THE ATTRIBUTES 

The task of assigning positive and negative scores to 

attributes in the numerical models were aided greatly by 

the indices prepared by Barton (1986a, b) and Cox (written commm., 1987). The indices contain information on 

the frequency of occurrence of geochemical anomalies, 

minerals, and types of alteration according to the descriptive models contained in Cox and Singer (1986). Associated with each attribute was an index number ranging from 

+5 down through 0 to -5 in a system similar to Prospector 

(Duda and others, 1977). The numbers represent the commonness or rarity of each attribute. It was the intent to 

have the numbers 1, 2, 3, 4, and 5 correspond, respectively, to the 0-10, 10-30, 30-70, 70-90, and 90-100 percent 

frequency relationship between the attribute and the deposits represented by the models. In almost all instances, the 

numbers assigned were "best" guesses based on experience. In the future, the compilation of such data would 

make the assignments less subjective. For the numerical 

models, the attributes were each assigned a positive and 

negative number for each model according to the levels 

given in table 1. Negative levels correspond to the frequency of occurrence and express how the absence of an 

attribute with respect to a particular model is to be weighted. Positive levels express how the presence of an attribute 

is suggestive of a particular model. For instance, a Leucogranite is highly suggestive (+4) of a Sn-greisen deposit 

Table 1. Quantization levels for presence/absence of particular mineral deposit 

State 

Presence 

Absence 

Level Verbal description 

Degree of sufficiency 

5 Very highly suggestive 

4 

3 

2 

Highly suggestive 

Moderately suggestive 

Mildly suggestive 

Weakly suggestive 

Degree of necessity 

-1 InfrequeJ}tlY present 

-2 Occasionally present 

-3 

-4 

-5 

Commonly present 

Most always present 

Virtually always present 

model. The known absence of Felsic-plutonic rocks in an 

area, however, virtually precludes (-5) the existence of Sn 

greisen deposits. Generally, the numbers were assigned so 

that they reflected as near as possible the context in which 

the attributes were defined by the compilers of each of the 

models. In the final analysis, however, the assignment is a 

trial-and-error process. 

In many cases, it was not possible even by trial and 

error to assign positive and negative numbers to the attributes. A rationale for assigning numbers was simply 

lacking. In these cases, default numbers of +2 and -2, respectively, were used. 

SCORING OF THE ATTRIBUTES 

The score that was assigned to an attribute in a numerical model was dependent upon the heading to which it 

belonged. In reviewing the descriptive models, it was recognized that the number of attributes within a heading varied from one model to the next. Different headings contained a different number of attributes. As a result, it was 

necessary to devise a weighting scheme that would take 

this into account. The intent was to balance the scores associated with each heading with the scores assigned to 

each attribute within each heading. In order to accomplish 

this, the levels in table 1 were associated with the scores 

given in table 2. Thus, the score associated with the highest positive (and negative) level for each heading reflects 

both its relative importance in defining a particular model 

and the number of attributes it contains. For example, the 

maximum score for a particular rock type cannot exceed 

7 
Table 2. Quantization levels and associated scores for mineral deposit models 

[Abbreviations: Age, AgeRange; Rk, RockTypes; Alt, Alteration; Min, Mineralogy; Gx, GeochemicalSignature; Gp, 

GeophysicalSignature; Dep, AssociatedDeposits. Default levels: 2, presence; -2, absence] 

Presence 

Level 5 4 3 2 

Age: 100 40 40 40 40 

Rk: 75 60 45 30 15 

Alt: 400 300 200 100 50 

Min: 75 60 45 30 15 

Gx: 75 60 45 30 15 

Gp: 250 150 50 25 10 

Dep: 400 320 200 150 75 

75. However, virtually all of the numerical models 

are characterized by several rock types. Thus, if all types 

are present, the total score for rock types will be many 

times 75. 

UNCERTAINTY IN THE EVIDENCE 

In Prospector, the geologist was asked to state the 

degree of certainty about the presence or absence of evidence (Duda and others, 1977). The degree of certainty 

was expressed on a scale from +5 through 0 to -5 for 

which +5 was taken as absolute certainty about the presence of the evidence and -5 was taken as absolute certainty about the absence of the evidence. A value of 0 was 

taken to mean indifferent or "don't know." The degree of 

belief expressed by the geologist was used to adjust the 

strength of the rules relating to the evidence. 

For the numerical models, a simpler method has 

been devised. For a given model, an attribute is judged as 

being present, suspected of being present (present?), missing, or absent. Absence is treated as the attribute having 

been looked for but not found. Missing is treated as the 

default, meaning that the attribute is neither present or suspected of being present nor known to be absent. If all of 

the attributes within a heading are missing, a default score 

of 0 is assigned to the heading. Thus, if no information 

exists on the known deposits in an area, the heading "AssociatedDeposits" is assigned a 0 score. If only some of 

the attributes within a heading are missing, the attributes 

that are missing are assigned the score corresponding to 

the level of -1. Attributes suspected of being present are 

assigned the next less positive level than the level associated with their presence. Experience to date indicates that 

this treatment of uncertainty in the observations is sufficient for taking into account the quality of the information 

available in regional mineral resource assessments. 

8 

Absence 

0 -1 -2 -3 -4 -5 

0 -100 -100 -100 -100 -100 

0 -5 -10 -45 -60 -75 

0 -2 -10 -100 -200 -400 

0 0 -5 -10 -30 -75 

0 0 -5 -10 -30 -75 

0 -10 -50 -100 -200 -250 

0 -50 -100 -200 -300 -400 

The "AgeRange" heading is treated differently from 

the other headings. A statement that was made for many of 

the descriptive models in Cox and Singer (1986) was that 

deposits of the type represented by the model are restricted 

mainly to one interval of geologic time but may be of any 

age. In this sense, "AgeRange" is not particularly restrictive for these models. It was decided to assign a single 

score to the "AgeRange" heading-namely, a score of 

+ 100 if any part of the interval specified by the geologist 

lies within the interval specified by the compiler of the 

model, a score of -100 if it did not, a score of +40 if the 

geologist was uncertain about the "AgeRange," and a 

score of 0 if no information is available. As defined by 

Singer and Cox (1988), "Age" refers to the age of the 

event responsible for the formation of the deposit. For 

many areas, this age is unknown. 

"TextureStructure" is not used as a basis for numerical scoring because it describes the morphology of deposits, and morphology is generally not well recognized at the 

time an assessment is made. If the morphology is known, 

the geologist tends to focus quickly on those models 

whose deposits exhibit these characteristics. The attributes 

within "TextureStructure" serve more as a checklist for 

identifying the types of deposit models to be considered in 

any given situation. 

WORKSHEETS FOR NUMERICAL MODELS 

Worksheets for the numerical mineral deposit models are given in appendix D. The model numbers for the 

numerical models correspond to the model numbers for the 

descriptive models in Cox and Singer (1986). The worksheets are designed to be reproduced and used to score 

geologic descriptions of areas that may contain mineral occurrences, prospects, or deposits. The worksheets can be 

used to determine numerically the degree to which a given 
geologic description matches a particular model. If, after 

scoring, there is doubt about the choice of a particular 

model, reference can always be made to the original model 

contained in Cox and Singer (1986). 

A WORKED EXAMPLE 

To illustrate how a person might fill in a worksheet, 

the following example is taken from field observations and 

subsequent thin-section studies and geochemical analyses 

of a massive, quartz-rich, seriate to porphyritic Tertiary 

granite that occurs in the White Mountains of east-central 

Alaska (Weber and others, 1988). An earlier investigation 

(Dean Warner, written commun., 1984) suggested that the 

granite might be a host for Sn greisen deposits. With this 

in mind, the worksheet for the Sn greisen deposit model 

was filled in using the scores in table 2 based on the information that was available. The worksheet along with the 

scores of the attributes, is shown in table 3. 

In the example, the age of the granite was established to be Tertiary and was considered to be the age of 

any mineralization that may have occurred. As a Tertiary 

age falls within the Phanerozoic age interval, a score of 

100 is assigned to Phanerozoic on the worksheet. 

Muscovite-leucogranite was identified as the major 

rock type present. On the worksheet, Muscovite-leucogranite is assigned a level of 3 for presence. Referring to table 

2, the score that is associated with a level of 3 for RockTypes (Rk) is 45. Therefore, the score for Muscovite-leucogranite is 45. Taking note that Muscovite-leucogranite is 

a kind-of Leucogranite, Leucogranite is also present therefore. On the worksheet, Leucogranite is assigned a level of 

4 for presence. Referring to table 2, the score that is associated with a level of 4 for Rk is 60, and therefore the 

score assigned to Leucogranite on the worksheet is 60. By 

similar reasoning, Granite and Felsic-plutonic RockTypes 

are also present, and by referring to table 2, they are each 

assigned the score of 75. The remaining RockType (Biotite-leucogranite) was missing-that is, neither its presence 

nor its absence could be confirmed. On the worksheet, Biotite-leucogranite is assigned a level of -2 for absence. As 

Biotite-leucogranite is considered missing rather than being absent, referring to table 2, the score associated with 

one level higher-that is, a level of -l-is -5, and therefore the score assigned to Biotite-leucogranite on the 

worksheet is -5. 

In a similar way, scores were assigned to the remaining attributes under the different headings on the worksheet. Under each heading, the score assigned to each attribute was based on the score associated with the level 

specified for the attribute depending on whether the attribute was judged to be present, suspected to be present 

(present?), missing, or absent. Attributes whose presenceabsence levels were not specified were assumed to be 2 

and -2, respectively. Under headings for which there was 

no information available, (AssociatedDeposits, for instance, in this example), the score assigned to all of the 

attributes was 0. 

When scores for all of the attributes were assigned, 

the partial scores-that is, the total scores under each 

heading-were calculated. 

The total score in this example was 1,055 out of a 

possible maximum score of 2,930. Although this score 

is relatively low compared with the maximum score, 

scores for the four next highest scores among all of the 

other models obtained using Prospector II were 637 out of 

2,430 for Sn veins, 576 out of 2,445 for Climax Mo, 559 

out of 1,730 for Porphyry Sn, and 466 out of 1,795 for W 

veins. It should be noted that absolute rather than relative 

scores are used for ranking purposes. It was concluded that 

even though this area could not be considered a likely 

prospect for Sn greisen deposits, if deposits should exist, 

they most likely would be of this type rather than any 

other type. 

This example brings out a problem that has persisted 

throughout the development of the models: the continuing 

confusion between regional and local characteristics. In 

performing regional mineral resource assessments, the 

scores obtained in applying the numerical models tend to 

be low, largely owing to the lack of information. At the 

same time, application of a particular model in an area in 

which the information is sufficient to conclude that, in all 

probability, one or more deposits of the type represented 

by the model do not exist results in large scores because 

the model, in detail, is not discriminating enough. Thus, 

even though such differences in scores that are obtained by 

application of the models in different areas are probably 

real and usable, reliance on absolute scores could lead to 

serious misinterpretation, and for this reason, caution is 

urged in applying the results indiscriminately. 

TEST OF NUMERICAL MODELS 

As a test of the numerical models, an experiment was 

performed that was designed to compare the results of classifying 124 lode deposits in Alaska by a panel of eight 

geologists using the Cox and Singer (1986) classification 

with the results obtained by classifying the same deposits 

using the numerical models. The 124 lode deposits were 

classified by the panel using the descriptions of the deposits given in Nokleberg and others (1987). Using the same 

descriptions, the 124 deposits were classified by Prospector 

II using the numerical models. The results of the experiment are summarized in table 4. The 124 deposits were 

classified by the panel of geologists into 27 different deposit types using the Cox and Singer classification. The 

five columns on the right in table 4 record the frequency of 

the rank order in which each of the 124 deposits was clas9 
Table 3. Worksheet for numerical model of Sn greisen deposits 

Model15c 

Worksheet for Numerical Model of Sn greisen deposits 

Deposit, Prospect, or Occurrence: Cache Mountain 

Location: White Mountains, East-Central Alaska 

Description: Quartz-rich seriate porphyritic granite with ubiquitious miarolitic cavities 

and common occurrence of tourmaline. 

AgeRange: Precambrian_ Phanerozoic ....1!!.0. 

RockTypes: Felsic-plutonic (5 -5) ~Granite (5 -5) ~Leucogranite 

(4 -4)...@. Muscovite-leucogranite (3 -2) ~Biotite-leucogranite 

(3 -2) ..:S. 

TextureStructure: Greisen Veinlets ~Stockwork __ 

Alteration: Greisenization (5 -2) ..::l.D Albitization (5 -2) ..:l.!l 

Tourmalinization (3 -2) .lllil 

Mineralogy: Cassiterite ( 4 -5) ...@Molybdenite ( 4 -5) ~Arsenopyrite 

(3 -5) _JU Topaz (4 -2)~ Tourmaline (4 -2)...@ Beryl (2 -4)..!! 

Wolframite (2 -3) ..:1!! Bismuthinite (2 -2) ...:S. Fluorite (4 -3)...@ 

Calcite (1 -3) .ll Pyrite (2 -4) _JU 

GeochemicaiSignature: Sn ( 4 -5) ...@ F (5 -5) ~ B (5 -4) ~ Mo (2 -5) ..!! 

Rb (2 -4) J! Cs (2 -4) Jl Be (2 -3) _JU REE (2 -4) .:J!l U (2 -4) _JU Th 

(2 -4) J! Nb (2 -4) Jl Ta (2 -4) J! Li (2 -4) J! W (2 -3) _JU As 

(2 -4) J! Bi (2 -3) _JU 

GeophysicaiSignature: 

AssociatedDeposits: Sn greisen..!! Sn veins..!! Sn replacement..!! 

MaxScore: 2,930 

Partial Scores 

AgeRange: ...1!!0 RockTypes: .1S.Q TextureStructure: j)_Aiteration: ..1.&! 

Mineralogy:~ GeochemicaiSignature: .Jill! GeophysicaiSignature:.J! 

AssociatedDeposits: ..!! 

Model Score: 1.055 

sified using the numerical models. For example, of the six 

deposits classified by the panel as being a Gabbroic Ni-Cu 

deposit type, four of these were also classified as being a 

Gabbroic Ni-Cu deposit type by Prospector II. For the other two deposits, however, a Gabbroic Ni-Cu deposit type 

was Prospector II's third choice for one and fifth choice for 

the other. It should be noted that for both of these deposits, 

the panel had a question mark after their choice. 

10 
""''' 

~ 

~') 

Table 4. Comparison of classification between Prospector II and panel of geologists using the 

Cox-Singer deposit classification for 124 metalliferous lode deposits in Alaska (Nokleberg and 

others, 1987) 

[Alphanumeric characters in parentheses refer to model numbers in Cox and Singer (1986)] 

Deposit type Frequency of ranking 

(classified by panel of geologists) (classified by Prospector II) 

1st 2nd 3rd 4th 5th 

1. Gabbroic Ni-Cu deposits (7a) 4 0 1 0 1 

2. Podiform chromite deposits (8a) 7 0 0 0 

3. Serpentine-hosted asbestos deposits (8d) 1 0 0 0 0 

4. Alaskan-POE (9) 5 0 0 0 0 

5. W skarn deposits (14a) 1 0 0 0 0 

6. Sn skarn deposits (14b) 2 0 0 0 0 

7. Sn vein deposits (15b) 0 1 0 0 

8. Sn greisen deposis (15c) 1 0 0 0 0 

9. Porphyry Cu deposits ( 17) 4 1 0 0 0 

10. Cu skarn deposits (18b) 2 0 1 0 0 

11. Zn-Pb skarn deposits (18c) 2 0 0 0 0 

12. Fe skarn deposits (18d) 4 1 0 0 0 

13. Porphyry Cu-Mo deposits (21a) 1 0 2 0 0 

14. Porphyry Mo, low F deposits (21b) 1 0 0 0 0 

15. Polymetallic vein deposits (22c) 14 3 0 0 0 

16. Basaltic Cu deposits (23) 0 0 1 0 0 

17. Cyprus massive sulfide deposits (24a) 0 0 1 0 0 

18. Bess hi massive sulfide deposits (24b) 3 0 0 0 0 

19. Epithermal vein deposits (25b, 25c, 25d, 25e) 2 0 0 0 0 

20. Hot-spring Hg deposits (27a) 3 1 0 0 0 

21. Sb-Au vein deposits (27d, 27e) 5 0 0 0 0 

22. Kuroko massive sulfide deposits (28a) 9 0 0 0 0 

23. Sandstone U deposits (30c) 1 0 0 0 0 

24. Sedimentary exhalative Zn-Pb deposits (31a) 2 0 0 0 0 

25. Bedded barite deposits (31 b) 2 0 0 0 0 

26. Kipushi Cu-Pb-Zn deposits (32c) 1 0 0 0 0 

27. Low-sulfide Au quartz vein deposits (36a) 25 0 0 0 

Totals 103 8 7 0 1 

Of the 124 deposits classified by the panel, 103 of 

these were classified the same by Prospector II. This represents an 83 percent agreement between the two sets of 

classifications. The deposit types for which there was perfect agreement between the two were Serpentine-hosted 

asbestos, Alaskan-PGE, W skarn, Sn skarn, Sn greisen, 

Zn-Pb skarn, Porphyry Mo-low F, Besshi massive sulfide, 

Epithermal vein, Sb-Au vein, Kuroko massive sulfide, 

Sandstone U, Sedimentary exhalative Zn-Pb, Bedded barite, and Kipushi Cu-Pb-Zn. In almost all cases, the deposit 

type receiving the highest score was clearly distinguishable 

from the other deposit types, which received considerably 

lower scores. There were 8 deposits for which the classification made by the panel was Prospector II's second 

choice. For 5 of these deposits, the panel either put a question mark after their choice or else suggested that the deposit could be considered one of two different deposit 

types. Such ambiguity highlights the fact that the classifi11 
cation of a deposit often is largely a matter of judgment. 

The scores obtained using Prospector II for each of the 9 

deposits characteristically were not markedly different for 

the first and second choices. By combining Prospector II's 

first and second choices as indicating a match with the 

classification made by the panel, there was agreement in 

111 out of the 119 deposits classified-that is, a 93 percent agreement. 

The deposit for which there was the most disagreement between the panel and Prospector II was the Spirit 

Mountain deposit (Nokleberg and others, 1987, p. 87). The 

panel classified this deposit as a Oabbroic Ni-Cu deposit 

type with a question mark, whereas Prospector II classified 

the deposit unequivocally as a Dunitic Ni-Cu deposit type 

(Cox and Singer, 1986, p. 24). The deposit is described as 

disseminations of sulfides in serpentinized peridotite and 

pyroxenite that are associated with gabbroic sills that have 

intruded upper Paleozoic limestones. The ore minerals 

contain Ni and Cu. This description fits closely with the 

Dunitic Ni-Cu deposit model described as disseminated 

sulfide mineralization in intrusive dunites and olivine peridotites that exhibit prograde and retrograde serpentinization. Although the description of the Oabbroic Ni-Cu deposit model is similar, what is lacking in the model is any 

mention of serpentinization. This attribute was critical in 

this instance. The three other deposit models that Prospector II rated higher than the Oabbroic Ni-Cu deposit model 

were the Alaskan-POE, Podiform chromite, and Serpentine-hosted asbestos deposit models. In order to resolve all 

the differences in the classification of this particular deposit, it would be necessary to review the description 

again with the panel members and compare it with the descriptions of these five models. 

A different situation exists for the Bernard Mountain 

deposit (Nokleberg and others, 1987, p. 55), in which the 

panel members classified the deposit as a Podiform chromite deposit type, whereas Prospector II narrowly classified the deposit as a Bushveld-Cr deposit type. The score 

for the Bushveld-Cr deposit model was 380 out of a possible 1,705, whereas the score for the Podiform chromite deposit model was 360 out of a possible 1 ,325. Situated in 

between these two models, were the scores for the Alaskan-POE and the Merensky-Reef-POE deposit models, 

which were 370 out of a possible 1,925 and 365 out of a 

possible 1 ,750, respectively. The relatively low scores 

obtained for all four of the models suggest that it may not 

12 

be possible with the present information to distinguish 

among them. 

CONCLUSIONS 

Numerical mineral deposit models demonstrate the 

technical feasibility of encoding descriptive mineral deposit 

models to provide (1) a numerical-based consultant for regional mineral resource assessments, (2) objective evaluations of particular geologic settings as part of regional assessments, and (3) determination of the most likely model 

or models that best match a particular geologic setting. This 

approach is potentially valuable for (1) screening data bases 

of mineral occurrences, (2) providing instruction about the 

geology of mineral deposits, (3) systematizing the development of mineral deposit models, and ( 4) introducing objective procedures for evaluating models numerically. 

While these numerical deposit models have useful 

applications in their present form, the extent to which their 

potential can be realized will depend upon future activities, 

some of which are already in progress. First, it is clear that 

the numerical models cannot be better than the descriptive 

models upon which they are based. The 87 numerical 

models represent but a sampling of what is ultimately desirable. Moreover, only a few of the numerical models 

have been completely tested and calibrated for regional 

mineral resource assessments. Many years will be required 

to develop numerical models for all types of deposits of 

economic interest, and refining these models and introducing new models as new deposit types are identified will be 

a continuing task. Fortunately, the formats that have been 

developed for the descriptive models will make it easier to 

carry out this task. 

Because the techniques used to develop numerical 

models are new, few geologists are familiar with them. As 

the advantages of this numerical approach become more 

widely appreciated, more geologists will be interested in 

becoming involved in this activity. Several activities could 

encourage their participation, including (1) further exposure of these ideas at professional conferences and workshops, (2) acceptance of the publication of such models as 

a significant professional activity, (3) incorporation of 

these ideas in a course on economic geology, and (4) provision of ways for geologists in the governmental, academic, and industrial communities to access the models by 

computer. 
Model11d 

DESCRIPTIVE MODEL OF THORIUM-RARE-EARTH VEINS 

By Mortimer H. Staatz 

BRIEF DESCRIPTION 

SYNONYM: Rare-earth-thorium veins. 

DESCRIPTION: Various thorium and rare-earth minerals in a quartz-potassium feldspar-iron-oxide gangue in veins 1 to about 

1,330 m long and less than 1 em to about 16m thick. 

TYPICAL DEPOSITS: Last Chance vein, Lemhi Pass district, Montana (Staatz, 1979); Little Johnnie vein, Powderhorn 

district, Colorado (Olson and Wallace, 1956); vein no. 12, southern Bear Lodge Mountains, Wyoming (Staatz, 1983); 

Wet Mountains area, Colorado (Armbrustmacher, 1988). 

RELATIVE IMPORTANCE: A future thorium resource. Highest grade thorium resource in the United States, second largest 

total resource of thorium (Staatz and others, 1979). Rare earths important byproduct in some deposits; in others, the 

principal product. 

COMMODITIES: Th, rare earths (mainly light rare earths, but at Laughlin Peak, New Mexico, the heavy rare earths most 

important). 

OTHER COMMODITIES: None. 

ASSOCIATED DEPOSIT TYPES (*suspected to be genetically related): Disseminated rare-earth minerals in both massive 

carbonatites and carbonatite dikes; example: one of the world's largest rare-earth deposits in a massive carbonatite at 

Mountain Pass, California (Olson and others, 1954). 

REGIONAL GEOLOGIC ATTRIBUTES 

TECTONOSTRATIGRAPHIC SETTING: Commonly associated with diverse suites of alkaline rocks and carbonatites. 

Thorium-rare-earth veins generally occur in an outerring around alkaline rocks (fig. 1). May be as far as 16 km beyond 

outer limits of the alkaline rocks. Veins most common in the eastern part of the Cordilleran belt associated with 

continental crustal rocks (Staatz and Armbrustmacher, 1982). 

REGIONAL DEPOSITIONAL ENVIRONMENT: Veins formed along fractures in brittle rocks. Vein fluids commonly 

traveled many kilometers before deposition. Ina few areas, such as the Powderhorn district(Olson and Hedlund, 1981), 

all related igneous rocks are exposed. From the center, igneous alkaline rock complex surrounds a massive carbonatite 

and is bordered by fenite. Carbonatite dikes intrude outer part of alkaline rocks and neighboring country rock. Thoriumrare-earth veins intruded into an outer zone (fig. 1). 

AGE RANGE: Host rock for veins: mainly Precambrian, but in several areas is Cretaceous and Tertiary. Veins: in Powderhorn 

and Wet Mountain districts, Colorado, formed between very late Precambrian to Ordovician (Olson and others, 1977); 

in Lemhi Pass district, Idaho and Montana (Staatz, 1972), Bear Lodge Mountains, Wyoming (Staatz, 1983), and 

Laughlin Peak area, New Mexico (Staatz, 1985), formed in Tertiary. 

LOCAL GEOLOGIC ATTRIBUTES 

HOST ROCKS: Hard brittle rocks. Rocks include Precambrian quartzite, hornblende schist, gneiss, granite; Upper Cretaceous 

Dakota Sandstone; Tertiary trachyte, phonolite, and intrusive breccia. 

AS SOCIA TED ROCKS: Alkalic rocks, carbonatites, fenites. 

ORE MINERALOGY: principal ore minerals in most deposits: thorite±monazite. Associated minerals: 

±brockite±allanite±bastnaesite. Exceptions: (1) Bear Lodge Mountains, Wyoming, no thorite, principally 

monazite±brockite±bastnaesite; (2) Laughlin Peak area, New Mexico, neither thorite nor monazite, principally either 

(a) brockite + xenotime or (b) thorium- and rare-earth-bearing crandallite. 

GANGUE MINERALS: Principal minerals: quartz+iron oxides (goethite and (or) hematite)±potassium feldspar. Minor 

minerals: ±barite±apatite±magnetite ±rutile±anatase±zircon (Staatz, 1974). 

13 
Model 11 d-Con. 

STRUCTURE and ZONING: Veins usually fine grained and commonly heavily stained with iron oxides±manganese oxides. 

Mineral zoning unknown. 

ORE CONTROLS: Large alkaline rock body or bodies, whose magma was source of vein fluids within about 20 km of veins 

(Staatz, 1974). Joints and small faults that served both as conduits for ore fluids and as sites of deposition. 

ISOTOPIC SIGNATURES: Unknown. 

FLUID INCLUSIONS: Unknown. 

STRUCTURAL SETTING: All ore in tabular veins. 

ORE DEPOSIT GEOMETRY: Veins of potential economic interest range in length from about 60 to about 1,330 m and in 

thickness from about 0.3 to about 16m. Veins may strike in almost any direction. Dips of all veins steep. 

ALTERATION: Iron minerals, where present, altered to goethite±lepidocrocite±hematite. Clay minerals not common; thorite 

often metamict, sometimes narrow zone of fenitization around vein. 

EFFECT OF WEATHERING: Probably aided in forming iron-oxide minerals. 

EFFECT OF METAMORPHISM: Not applicable. 

GEOCHEMICAL SIGNATURES: Some enrichment of Th and rare earths in alkaline igneous rocks. Th tends to disperse 

rapidly in stream sediments short distances below veins (Staatz and others, 1971). Heavy metals in stream sediments 

not diagnostic. 

GEOPHYSICAL SIGNATURES: Radiation due to thorium used to locate most veins. Generally located by hand-held geiger 

counter or scintillometer. Most veins too narrow and (or) poorly exposed to locate with airborne radiation counters. 

OTHER EXPLORATION GUIDES: Unknown. 

OVERBURDEN: Most known veins have some part exposed at surface. Veins have been traced from original exposure under 

as much as 10m of overburden. 

14 
~') 

~ 

~c 

Massive carbonatite 

T 

~ 

~ y 

A 

-v 

"'\-

{ 

B 

T-1 

c 

* 

T 

~ T 

* 

T 

T~ 

4fT 

~ -*""T 

""'*- T 

Diverse alkalic rocks 

~T 

~T *T * ~ 

Country rock 

Tf * * 

alkalic rocks 

EXPLANATION 

rock T --*- Thorium veins 

c -++- Carbonatite dikes 

Figure 1. Idealized model showing relationship of thorium-rare-earth veins to alkalic 

rocks and carbonatites. A, Plan view. B, Cross-section view. 

Model 11 d-Con. 

15 
Model 11 d-Con. 

GRADE AND TONNAGE MODEL OF THORIUM-RARE-EARTH VEINS 

By James D. Bliss 

COMMENTS Definition of deposits for thorium -rare-earth veins used for this model is subject to several types of complications. 

Definition of vein-type deposits is never an easy task, since veins and mines exhibit various types of spatial relationships. 

Reports about thorium-rare-earth veins also show veins and mines using different scales. Some of the veins have been 

worked by small-scale mining. The majority ofthe veins are unmined. Production data are usually not available. Data on 

reserves, if known, are also not available. Production grades are not known. In some cases the distinction between 

carbonatite veins and thorium-rare-earth veins is unclear, and thus the model may contain carbonatite veins in error. To 

develop a model, several rules were established: ( 1) grades were estimated using the median values reported from samples 

taken from the veins; (2) when possible, veins were treated as a single deposit if they occurred within 1 km of each other; 

and (3) tonnage was estimated using median vein widths, lengths, and depths (depths estimated as 2.5 times length). Rules 

were applied when possible; in some cases, deposits were not used, since the rules could not be clearly applied. Thoriumrare-earth veins in the Powderhorn and Mountain Pass districts were considered, but data were found inadequate for 

estimation of grades and tonnages for veins using the stated rules. Some districts with closely spaced veins are treated as 

a single deposit. The model is probably biased in ways undefined, since none of the data are from deposits worked to 

exhaustion. See appendix B for locality abbreviations. See introduction for explanation of the grade and tonnage model 

as shown in figures 2-4. 

DEPOSITS DEPOSITS 

Name Country Name Country 

Apex USID . I&L USAK 

Beardsley us co Last Chance USMT 

Beaverhead USMT Lone Star No. 2 USID 

Black Bear No. 2 USID Lucky Horseshoe USID 

Black Bull No. 3 USID Nellie B USID 

Black Rock USMT Paystreak USAK 

Black Rock USID Quartzite USAZ 

Buffalo USID Reactor USMT 

CageNo. 12 USID Schwarz Ranch us co 

Capitan Mountain USNM Silver Queen 38A USID 

Contact USID Silver Queen 52B USID 

Cottonwood USAZ Th02 USID 

Deer Fraction 1A USID Tuttle Ranch us co 

Elkhorn USMT Unnamed property MXCO 

General Ike us co Wonder USID 

Haputa Ranch us co Wonder No. 18-Little Dandy USID 

16 
0.9 

0.8 

~ 0.7 

U5 

0 

a.. 

w 0.6 

0 

LL 

0 

z 0.5 

0 

i= 

a: 0 0.4 

a.. 

0 

g: 0.3 

0.2 

0.1 

• • 

o.o USGS 0.007 

0.0016 0.0063 

Thorium-rare-earth veins 

n:32 

1,600 

TONNAGE, IN MILLION METRIC TONS 

Thorium-rare-earth veins 

1.0 r---~-------"T"'""--.-----,----r---or----,---r-----, 

0.9 

0.8 

~ 0.7 

U5 

0 

a.. 

w 0.6 

0 

LL 

0 z 0.5 

0 

i= 

a: 0.4 

0 

a.. 

0 

g: 0.3 

0.2 

0.1 

• 1!=32 

USGS 

THORIUM-OXIDE GRADE, IN PERCENT 

Model 11 d-Con. 

Figure 2. Tonnages of thorium-rare-earth veins. 

Figure 3. Thorium-oxide grades of thoriumrare-earth veins. 

17 
Model 11 d-Con. 

, 

I 

Thorium-rare-earth veins 

1.0 

11=32 

0.9 

0.8 

(/) 0.7 I--

(j) 

0 

a.. 

w 0.6 

0 

u.. 

0 0.5 z 

0 

i= 

a: 0.4 0 

a.. 

0 

a: 0.3 a.. 

0.2 

0.1 

USGS 

10.0 

RARE-EARTH-OXIDE GRADE, IN PERCENT 

Figure 4. Rare-earth-oxide grades of thorium-rare-earth veins. 

18 
Model19c 

DESCRIPTIVE MODEL OF DISTAL DISSEMINATED Ag-Au 

By Dennis P. Cox 

BRIEF DESCRIPTION 

SYNONYM: Sediment-hosted Ag-Au, disseminated Ag 

DESCRIPTION: Disseminated Ag and Au mainly in sedimentary rocks distal to porphyry Cu, skams, and polymetallic veins 

(Graybeal, 1981). 

TYPICAL DEPOSITS: Taylor, Candelaria, Star Pointer, Cove deposits, White Pine district, Nevada; Tecoma, Utah; Vekol, 

Tombstone, and Hardshell, Arizona. · 

DISTINGUISHING FEATURES: This model is similar to sediment-hosted Au but has significantly higher Ag grades than 

that model (see Ag grades in grade and tonnage models for both). It also is characterized by higher geochemical 

background values 

COMMODITIES: Ag, Au 

OTHER COMMODITIES: Locally, Sb 

AS SOCIA TED DEPOSIT TYPES: Porphyry Cu, Cu skarn, Pb-Zn skarn, Au skarn, polymetallic veins, polymetallic 

replacement and replacement Mn deposits. 

REGIONAL GEOLOGIC ATTRIBUTES 

TECTONOSTRATIGRAPHIC SETTING: Continental margins. 

REGIONAL DEPOSITIONAL ENVIRONMENT: Shelf and basinal sedimentary rocks are folded and faulted and intruded 

by 1-type granitic rocks. 

AGE RANGE: Mesozoic-Tertiary in Western United States; may be any age. 

LOCAL GEOLOGIC ATTRIBUTES 

HOST ROCKS: Carbonate and clastic sedimentary rocks. 

AS SOCIA TED ROCKS: Felsic hypabyssal or subvolcanic intrusions. 

ORE MINERALOGY: Native Au, native Ag, electrum, argentite, Ag sulfosalts, tetrahedrite, stibnite, galena, sphalerite, 

chalcopyrite, pyrite, marcasite, arsenopyrite; at Cove deposits, stannite and canfieldite. 

GANGUE MINERALS: Quartz, rhodochrosite, Ag-rich manganocalcite. 

STRUCTURE AND ZONING: Ore minerals sparsely disseminated or in stockwork of thin quartz-sulfide veins. 

ORE CONTROLS: Deposits commonly occur in skarn and polymetallic vein and replacement districts outboard of all other 

types of mineralization. Fracture permeability is the most important ore control. Primary rock permeability may be 

important locally 

STRUCTURAL SETTING: Shear zones, axial plane fractures in folded rocks 

ORE DEPOSIT GEOMETRY: Irregular bodies, locally conformable to bedding 

ALTERATION: Silicification (Taylor, Star Pointer, Cove) and decalcification (Star Pointer) of carbonate rocks; sericite-clay 

in clastic rocks (Candelaria). 

EFFECT OF WEATHERING: Leaching and redeposition of Ag as cerargyrite forms bonanza deposits (White Pine district, 

Nevada; Vekol, Arizona) .. 

GEOCHEMICAL SIGNATURES: Ag±Au±Pb±Mn±Zn±Cu±Sb±As±Hg±Te; Mn introduced at Cove, Candelaria, and Star 

Pointer. Ag:Au ratios are highly variable: Candelaria 400: 1; Taylor, 143:1; Tecoma, 60: 1; Purisima Concepi6n, 51: 1; 

Hilltop, <2: 1. 

19 
Model 19c-Con. 

GRADE AND TONNAGE MODEL OF DISTAL DISSEMINATED Ag-Au 

By Dennis P. Cox and Donald A. Singer 

COMMENTS Estimated premining tonnages and grades from the deposits listed in table 5 were used to construct the model. 

20 

Where several different estimates were available for a deposit, the estimated tonnage associated with lowest cutoff grades 

was used. 

No significant correlations between grades and tonnages were observed. See appendix B for locality abbreviations. See 

introduction for explanation of the grade and tonnage model as shown in figures 5-7. 

Table 5. Grades and tonnages of distal disseminated Ag-Au deposits 

[Tonnages in million metric tons; silver (Ag) and gold (Au) grades in grams per metric ton. Country and state 

abbreviations explained in app. B] 

Deposit Country 

Candelaria---------------------------------- USNV 

Cove----------------------------------------- USNV 

Fresnillo------------------------------------ MXCO 

Hardshell ----------------------------------- USAZ 

Hilltop-------------------------------------- USNV 

Purisima Concepcion-------------------- PERU 

Real de Angeles--------------------------- MXCO 

Star Pointer-------------------------------- USNV 

Taylor--------------------------------------- USNV 

Tecoma-------------------------------------- USUT 

Tonnage 

27 

81 

19 

6 

10.35 

.2 

66 

1.36 

7 

1.5 

Au grade Ag grade 

0.19 50 

1.8 92.5 

.22 141.6 

0 245 

2.5 2 

3.1 7.5 

0 66.6 

4.8 10.3 

0 103 

1.56 93.3 

, 

I 
0.9 

0.8 

~ 0.7 

Ci5 

0 

a. 

w 0.6 

0 

LL 

~ 0.5 

0 

i= 

0:: 0.4 

0 

a. 

0 

g: 0.3 

0.2 

0.1 

0.9 

0.8 

(/) !:: 0.7 

(/) 

0 

a. 

w 0.6 

0 

LL 

~ 0.5 

0 

i= 

0:: 0.4 0 

a. 

0 

g: 0.3 

0.2 

0.1 

Distal disseminated Ag-Au 

USGS 

TONNAGE, IN MILLION METRIC TONS 

Distal disseminated Ag-Au 

• 

• 

GOLD GRADE, IN GRAMS PER METRIC TON 

n=10 

n=10 

100 

Model 19c-Con. 

Figure 5. Tonnages of distal disseminated 

Ag-Au deposits. 

Figure 6. Gold grades of distal disseminated 

Ag-Au deposits. 

21 
Model 19c-Con. 

Distal disseminated Ag-Au 

1.0 

n=10 

0.9 

0.8 

(/') 0.7 tU5 

0 

a.. 

w 0.6 

0 

LL 

0 0.5 z 

Q 

tcr: 0.4 0 

a.. 

0 

cr: 0.3 a.. 

0.2 

0.1 

0.0 USGS 

0.4 1.0 2.5 4000 

SILVER GRADE, IN GRAMS PER METRIC TON 

Figure 7. Silver grades of distal disseminated Ag-Au deposits. 

22 
~·) 

Model25a 

GRADE AND TONNAGE MODEL OF HOT-SPRING Au-Ag 

By Byron R. Berger and Donald A. Singer 

COM:MENTS This model applies to the descriptive model for hot-spring Au-Ag (No. 25a) by Berger (1986b). It is a modified 

version of a previously published report (Berger and Singer, 1987). Estimated premining tonnages and grades from the 

deposits listed in table 6 were used to construct the model. Where several different estimates were available for a deposit, 

the estimated tonnage associated with lowest cutoff grades was used. 

No significant correlations between grades and tonnages were observed. See appendix B for locality abbreviations. See 

introduction for explanation of the grade and tonnage model as shown in figures 8-10. 

Table 6. Grades and tonnages of hot-spring Au-Ag deposits 

[Tonnage in million metric tons; gold (Au) and silver (Ag) grades in grams per metric ton. Country and 

state abbreviations explained in app. B] 

Deposit Country Tonnage Au grade 

Atlanta -------------------------------------- USNV 1.0 2.742 

Borealis ------------------------------------- USNV 4.17 2.571 

Buckhorn ----------------------------------- USNV 4.54 1.51 

Crowfoot ----------------------------------- USNV 22.68 .857 

Fire Creek ---------------------------------- USNV .3174 2.057 

Florida Canyon ---------------------------- USNV 35.87 .788 

Hasbrouck ---------------------------------- USNV 11.7 1.0 

Hog Ranch --------------------------------- USNV 30 1.767 

Ivanhoe ------------------------------------- USNV 75.73 1.166 

Lewis---------------------------------------- USNV 9.07 1.37 

McLaughlin -------------------------------- USCA 18.1 5.48 

Mother l..ode ------------------------------- USNV 4.44 1.851 

Paradise Peak ------------------------------ USNV 16.48 2.894 

Rawhide------------------------------------- USNV 35.46 1.135 

RoundMtn. ---------------- USNV 243.8 1.136 

Sleeper -------------------------------------- USNV 47.41 1.664 

Wind Mtn. ---------------------------------- USNV 13.61 .72 

Ag grade 

54.8 

17.14 

20.05 

0 

0 

0 

20.2 

.088 

0 

0 

0 

0 

80.18 

16.11 

2.113 

5.0 

14.4 

23 
Model 2Sa-Con. 

Figure 8. Tonnages of hot-spring Au-Ag deposits. 

Figure 9. Gold grades of hot-spring Au-Ag 

deposits. 

24 

(/) 

ICi5 

0 

D... 

w 

0 

LL 

0 

z 

Q 

Ia: 

0 

D... 

0 

a: 

D... 

(/) 

ICi5 

0 

D... 

w 

0 

LL 

0 

z 

0 

i= 

a: 

0 

D... 

0 

a: 

D... 

Hot-spring Au-Ag 

1.0 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0.0 USGS 

0.0016 1,600 

TONNAGE, IN MILLION METRIC TONS 

Hot-spring Au-Ag 

1.0 

n=17 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

o.o USGS 

0.01 0.025 0.063 0.16 0.4 1.0 2.5 6.3 16 40 100 

GOLD GRADE, IN GRAMS PER METRIC TON 
0.9 

0.8 

~ 0.7 

Ci5 

0 

Cl.. 

w 0.6 

0 

LL 

0 0.5 z 

0 

~ 

a: 0.4 0 

Cl.. 

0 

g: 0.3 

0.2 

0.1 

Hot-spring Au-Ag 

SILVER GRADE, IN GRAMS PER METRIC TON 

Figure 10. Silver grades of hot-spring Au-Ag deposits. (Silver grade of 

0.088 g/mt for Hog Ranch not shown.) 

Model 25a-Con. 

25 
Model26a 

GRADE AND TONNAGE MODEL OF SEDIMENT-HOSTED Au 

By Dan L. Mosier, Donald A. Singer, William C. Bagby, and W. David Menzie 

COMMENTS This model applies to the descriptive model for carbonate-hosted Au-Ag (Berger, 1986a) and supersedes the 

grade and tonnage model for that deposit type (Bagby and others, 1986). The change in the model name reflects the 

discovery of many deposits in siliceous shale and other noncarbonate host rocks and the reassignment of some silver-rich 

deposits to the distal disseminated Ag-Au type (that is, Hilltop, Candelaria, and Taylor); the few deposits remaining with 

reported silver grades are Alligator Ridge, Dee, and Standard. Other deposits in the original set were deemed atypical (Bald 

Mountain, Windfall, Giltedge, Tolman) or reclassified as other types (Atlanta and Florida Canyon-now considered hot 

spring Au). This model represents considerable refinement ofthe data used by Bagby and others (1986). Deposits where 

mineralization is known to be within 500 m of each other were combined. Most of the names listed in table 7 are property 

names that contain multiple zones or deposits. Well-known property names containing multiple deposits that are over 500 

m apart, such as Jerritt Canyon, are listed individually with corresponding deposit names in parentheses. For some property 

names with multiple deposits, such as Marigold, only the well-explored deposits were included and are shown in 

parentheses. This model excludes deposits for which information on distances between discrete orebodies was not 

available at the time of the compilation (for example, Big Springs, Northumberland, and Tonkin Springs). The distribution 

of tonnages is significantly skewed toward larger tonnages because of the two very large deposits. No geologic reason has 

been found to distinguish these large deposits from the other deposits; however, these two deposits appear to be more 

thoroughly explored, both laterally and vertically, than most of the other deposits, suggesting that many of the other 

deposits will eventually be found to be much larger than now estimated. See appendix B for locality abbreviations. See 

introduction for explanation of the grade and tonnage model as shown in figures 11-13. 

26 

Table 7. Grades and tonnages of sediment-hosted Au deposits 

[Tonnages in million metric tons; gold (Au) and silver (Ag) grades in grams per metric ton. Country and state abbreviations explained in app. B] 

Name Country 

Alligator Ridge-------------------------------- USNV 

A us tin------------------------------------------- USNV 

Bootstrap-Capstone-------------------------- USNV 

Bullion Monarch-Lantern------------------ USNV 

Carlin------------------------------------------- USNV 

Chimney Creek North------------------------ USNV 

Chimney Creek South------------------------ USNV 

Cortez------------------------------------------- USNV 

Dee----------------------------------------------- USNV 

Emigrant Springs 1--------------------------- USNV 

Emigrant Springs 2--------------------------- USNV 

Felix Canyon---------------------------------- USNV 

Getchell----------------------------------------- USNV 

Gold Acres-·------------------------------------- USNV 

Gold Bar ---------------------------------------- USNV 

Goldstone-Gold Ridge----------------------- USNV 

Gold Quarry-Deep West-Maggie Creek USNV 

Goldstrike-Post-Deep Post-Blue StarGenesis-Bobcat-North Star USNV 

Green Springs (C Pit) ------------------------ USNV 

Tonnage 

6.35 

1.59 

22.90 

14.90 

32.85 

27.60 

53.00 

3.18 

5.13 

10.44 

3.60 

.32 

13.97 

8.34 

3.95 

6.75 

464.00 

306.62 

1.1 

Au grade Ag grade 

3.29 0.72 

5.49 0 

1.46 0 

1.11 0 

4.11 0 

2.14 0 

2.4 0 

9.60 0 

2.78 2.6 

.82 0 

1.37 0 

1.03 0 

6.65 0 

3.35 0 

2.87 0 

3.4 0 

1.32 0 

2.89 0 

2.1 0 
1.0 

0.9 

0.8 

(f) 0.7 1-

(j) 

0 

0.... 

w 0.6 

0 

L1.. 

0 0.5 z 

0 

t= 

a: 0.4 0 

0.... 

0 

a: 0.3 0.... 

0.2 

0.1 

0.0 USGS • 0.0011> 

Model 26a-Con. 

Table 7. Grades and tonnages of sediment-hosted Au deposits-Continued 

Name Country 

Horse Canyon--------------------------------- USNV 

Illipah------------------------------------------- USNV 

Jerritt Canyon (Bell mine)------------------ USNV 

Jerritt Canyon (Bums Basin)--------------- USNV 

Jerritt Canyon (Mill Creek)----------------- USNV 

Jerritt Canyon (Saval Canyon)------------- USNV 

Jerritt Canyon (Winters Creek)------------ USNV 

Jerritt Canyon (Wright Window)---------- USNV 

Marigold (East Hill Zone)------------------- USNV 

Marigold (8 South Zone)-------------------- USNV 

Mcrcur ------------------------------------------- USUT 

Nighthawk ------------------------------------- USNV 

Pete---------------------------------------------- USNV 

Pinson------------------------------------------ USNV 

Preble ------------------------------------------- USNV 

Rain-Gnome----------------------------------- USNV 

South Bullion---------------------------------- USNV 

Southern Mining Zone----------------------- USNV 

Standard----------------------------------------- USNV 

Tusc---------------------------------------------- USNV 

Sediment-hosted Au 

TONNAGE, IN MILLION METRIC TONS 

1}=39 

Tonnage Au grade Ag grade 

4.54 3.43 0 

1.03 1.13 0 

15.40 7.06 0 

3.67 5.11 0 

1.00 5.80 0 

2.27 4.15 0 

1.27 5.2 0 

1.18 3.26 0 

6.65 .72 0 

4.5 2.91 0 

29.70 2.07 0 

4.35 1.2 0 

14.29 1.03 0 

9.80 2.60 0 

3.00 3.29 0 

22.95 1.76 0 

18.14 .89 0 

1.44 .65 0 

.80 1.65 3.43 

18.80 1.20 0 

Figure 11. T onnagcs of sediment-hosted Au 

deposits. 

27 
Model 26a-Con. 

Figure 12. Gold grades of sediment-hosted Au 

deposits. 

Figure 13. Silver grades of sediment-hosted Au 

deposits 

28 

C/) 

1--

Ci5 

0 

Q. 

w 

0 

LL 

0 

z 

0 

i= 

c: 

0 

Q. 

0 

c: 

Q. 

(/) 

1--

Ci5 

0 

Q. 

w 

0 

LL 

0 

z 

0 

i= 

a: 

0 

Q. 

0 

a: 

Q. 

1.0 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0.0 USGS 

O.D1 

1.0 I 

0.9 

0.8 r0.7 ~ 

0.6 

0.5 -

0.4 ~ 

0.3 

0.2 -

0.1 ~ 

• 0.0 USGS I 

0.4 1.0 

Sediment-hosted Au 

100 

GOLD GRADE, IN GRAMS PER METRIC TON 

Sediment-hosted Au 

I I I I I I 

n=39 

-

-

-

-

-

-

-

-

-

• 

I e I I I I I I I 

2.5 6.3 16 40 100 250 630 1600 4000 

SILVER GRADE, IN GRAMS PER METRIC TON ~r 
Model28a.1 

GRADE AND TONNAGE MODEL OF SIERRAN KUROKO DEPOSITS 

By Donald A. Singer 

COMMENTS This model applies to the descriptive model for kuroko massive sulfide (No. 28a) by Singer ( 1986); however, only 

kuroko deposits of Triassic or Jurassic age in North America were used to construct this subset (table 8). Because many 

· of the deposits lie in the western foothills of the SierraN evada in California, the name Sierran kuroko is given to the group. 

These deposits are significantly smaller in tonnage than the worldwide kuroko group. The reason for this difference is not 

known. Estimated premining tonnages and grades or total production from the deposits listed below were used to construct 

the model. Where several different estimates were available for a deposit, the estimated tonnage associated with lowest 

cutoff grades was used. 

The breaks in slopes of the lead, silver, gold, and zinc plots (figs. 16-19) may be related to underreporting of production 

grades caused by early ore-processing problems. Silver grade is correlated with gold grade (r= 0. 76, n= 16). See appendix 

B for locality abbreviations. See introduction for explanation of the grade and tonnage model as shown in figures 14-19. 

Table 8. Grades and tonnages of Sierran kuroko deposits 

[Tonnages in million metric tons; silver (Ag) and gold (Au) grades in grams per metric ton; other grades in percent. Country and state 

abbreviations explained in app. B) 

Deposit Country Tonnage Cu grade Zn grade Pb grade Ag grade Au grade 

Afterthought-------------------------------- USCA 0.151 3.23 16.15 2.17 190 1 

Big Bend------------------------------------ USCA .05 1.14 10.7 .2 41.4 1.54 

Blue udge --------------------------------- USCA .18 4.1 2 0 187 4.3 

Blue Moon -.:.------------------------------· USCA .105 .36 12.5 .45 123 2.09 

Bully Hill-Rising Star-------------------- USCA .62 3.8 3.1 0 130 1.98 

Copper Crown ----------------------------- CNBC .211 .31 4.25 0 25 0 

Copper Hill--------------------------------· USCA .266 .43 0 0 0 0 

Cronin--------------------------------------- CNBC .054 8.12 7.11 0 431 .34 

Double Ed ---------------------------------- CNBC 3.63 1 .6 0 0 0 

Duthie ·--------------------------------------· CNBC .118 .4 6.5 2.8 106.5 1.27 

George Copper----------------------------- CNBC .553 2 0 0 17.2 2.06 

Gray Eagle --------------------------------· USCA 1.33 3.8 0 0 17.6 6.17 

Greens Creek------------------------------· USAK 3.629 .5 9 2.5 343 3.4 

Keystone-Union --------------------------· USCA 1.2 2.37 0 0 .75 .01 

Mamie-·-------------------------------------· CNBC .055 .7 7.6 0 0 11 

Newton-------------------------------------- USCA .15 3.51 .2 0 13.6 .17 

North Keystone ---------------------------- USCA .205 2.2 0 0 1.3 .02 

Penn ----------------------------------------- USCA .884 4.24 1.14 .06 75 2.38 

Red Wing ----------------------------------· CNBC .181 2 0 0 0 0 

Silver Queen ------------------------------- CNBC .363 .76 6 2.1 275 3.1 

Spenceville --------------------------------- USCA .136 5 0 0 0 0 

Sunshine -----------------------------------· CNBC .313 .18 4.8 1.69 12.2 0 

Tulsequah ----------------------------------- CNBC 1.62 1.27 6.9 1.26 140 4.04 

29 
Model 28a.1-Con. 

Figure 14. Tonnages of Sierran kuroko deposits. 

Figure 15. Copper grades of Sierran kuroko 

deposits. 

30 

CJ) 

rU5 

0 

c... 

w 

0 

u.. 

0 

z 

0 

~ 

a: 

0 

c... 

0 

a: 

c... 

CJ) 

1-

U5 

0 

c... 

w 

0 

u.. 

0 

z 

0 

~ 

a: 

0 

c... 

0 

a: 

c... 

Sierran kuroko 

1.0 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

1,600 

TONNAGE, IN MILLION METRIC TONS 

Sierran kuroko 

1.0 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0.0 USGS 

0.032 

COPPER GRADE, IN PERCENT 
Model 28a.1-Con. 

~,, 

~ Sierran kuroko 

1.0 

n-23 

0.9 

0.8 

(/') 

0.7 I- • (j) 

0 • 0.. 

w 0.6 

Cl 

LL 

0 

z 0.5 

0 

i= 

a: 0.4 0 

0.. 

0 

a: 0.3 0.. 

0.2 

0.1 

Figure 16. Zinc grades of Sierran kuroko 

0.0 USGS deposits. 

0.01 0.025 0.063 0.16 0.4 1.0 2.5 6.3 16 40 100 

ZINC GRADE, IN PERCENT 

~') 

Sierran kuroko 

1.0 

n=23 

0.9 

0.8 

(/') 0.7 !:::: 

(/') 

0 

0.. 

w 0.6 

Cl 

LL 

0 0.5 z 

0 

i= 

a: 0.4 0 • 0.. 

0 

a: 0.3 0.. 

0.2 

0.1 

Figure 17. Lead grades of Sierran kuroko 

~') deposits. 40 100 

LEAD GRADE, IN PERCENT 

31 
Model 28a.1-Con. 

Figure 18. Gold grades of Sierran kuroko 

deposits. (Gold grade for Keystone-Union not 

shown.) 

Figure 19. Silver grades of Sierran kuroko 

deposits. 

32 

(/) 

1-

U5 

0 

a.. 

w 

0 

LL 

0 

z 

0 

i= 

c: 

0 

a.. 

0 

c: 

a.. 

1.0 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0.0 USGS 

0.01 

Sierran kuroko 

nc23 

• 

• 

• 

100 

GOLD GRADE, IN GRAMS PER METRIC TON 

Sierran kuroko 

nc23 

• 

4000 

SILVER GRADE, IN GRAMS PER METRIC TON 
~fl 

DESCRIPTIVE MODEL OF SOLUTION-COLLAPSE 

BRECCIA PIPE URANIUM DEPOSITS 

By Warren I. Finch 

BRIEF DESCRIPTION 

Model32e 

SYNONYM: Collapse breccia pipe deposits, sedimentary breccia pipe deposits, Orphan Lode-type deposit. 

DESCRIPTION: Uraninite and associated sulfide, arsenide, sulfate, and arsenic-sulfosalt minerals as disseminated replacements and minor fracture fillings in distinct bodies in near-vertical cylindrical solution-collapse breccia pipes, 30-175 

m in diameter and 1,000 m in length. Pipes located in flat-lying upper Paleozoic and Triassic rocks restricted to the 

Grand Canyon region in the southwestern part of the Colorado Plateau. 

TYPICAL DEPOSITS: Orphan Lode (Chenoweth, 1986; Gornitz and others, 1988), EZ-2 (Krewedl and Carisey, 1986), 

Pigeon (Schafer, 1988), all in Arizona. 

RELATIVE IMPORTANCE: One of two dominant high-grade sources ofUnited States uranium production in 1987; expected 

to be major source of future uranium production within the United States. 

COMMODITIES: U 

OTHER COMMODITIES: ± Cu± V± Ag± Au 

AS SOCIA TED DEPOSIT TYPES (*suspected to be genetically related): *Sandstone uranium; supergene enrichment of 

Cu and V and depletion ofU in deeply eroded and weathered pipes-typical example, Ridenour, Arizona (Chenoweth, 

1988); Apex germanium- and gallium-bearing breccia pipe nearby in Basin and Range province (Wenrich and others, 

1987). 

REGIONAL GEOLOGIC ATTRIBUTES 

TECTONOSTRATIGRAPHIC SETTING: Pipes found within and along the southwest margin of the Colorado Plateau, in 

a stable block existent since the Precambrian and resistant to tectonic forces acting on the western part of the North 

American plate. Wall rocks of pipes were deposited on a stable marine platform. Pipes apparently originated along and 

at intersections ofN. SOOE.-and N. 45°W.-trendingjointorfracturesets(Wenrich and Sutphin, 1989),roughlyparallel 

to orthogonal Colorado River(N. 45°E.), Zuni (N. 45°W), and related lineaments shown by Green (1988, fig. 4) that 

developed in the Precambrian and rejuvenated in later periods. No igneous rocks are found in the pipes. 

REGIONAL DEPOSITIONAL ENVIRONMENT: Breccia pipes developed from solution collapse within the thick 

Mississippian Redwall Limestone (0-210 m) beginning in the Late Mississippian and propagated upward into 

overlying strata of carbonate-cemented sandstone, siltstone, limestone, and conglomerate for at least 1,000 m, 

apparently only where the Red wall is> 15m thick. Stoping was intermittently active and reached the lower members 

of the Chinle Formation in Late Triassic time. 

AGE RANGE: Host wall rocks for pipes: Late Mississippian to Late Triassic. Ores: 260-200 Ma(Ludwig and Simmons, 1988). 

LOCAL GEOLOGIC ATTRIBUTES 

HOST ROCKS: Karst-collapse breccia. Breccia clasts as wide as 10 m across, consisting mainly of sandstone (-90 percent) 

and siltstone (-10 percent), occur in a matrix of quartz grains that is commonly well cemented with carbonate minerals. 

Minor claystone and limestone clasts. 

AS SOCIA TED ROCKS: Unbrecciated flat-lying sandstone, siltstone, and limestone. 

ORE MINERALOGY: Principal ore minerals: uraninite±roscoelite± tyuyamunite*±torbernite*±uranophane*±zeunerite* 

±chalcopyrite±bornite*±chalcocite*±malachite*±azurite *±brochantite *±volborthite±naumannite. Associated basemetal minerals: ±sphalerite ±galena±bravoite± rammelsbergite±stibnite ±molybdenite±skutterudite. An asterisk 

indicates sugergene origin. Pre-uraninite mineral assemblages resemble those of Mississippi Valley-type deposits. 

Unusual complexity of mineralogy shown in appendix E. 

GANGUE MINERALS: Pyrite+marcasite+calcite+dolomite+barite+anhydrite±siderite±hematite±limonite±goethite 

±pyrobitumen (see app. E). 

33 
Model 32e-Con. 

TEXTURE AND MINERAL ZONING: Ore bodies occur as discontinuous pods mainly in the core of the breccia pipe, but 

some are also found in the annular-ring structure and may occupy as much as a 200-m vertical interval (fig. 20). Mainly 

replacement and sparse open-space filling. Pyrite/marcasite and base-metal sulfides, locally associated with pyrobitumen, form a discontinuous "massive sulfide cap" above the uranium deposits in many pipes. Uranium, vanadium, 

and copper roughly zoned within some deposits. 

ORE CONTROLS: Fractured,permeablerockwithin breccia pipe. Nearly allprimaryoreconfined to the breccia pipe: rarely, 

a little uranium ore is reported in relatively undisturbed beds outside the ring structure. Vertically, most primary ore 

is below the Coconino Sandstone and at the level of the Hermit Shale and the Esplanade Sandstone of the Supai Group 

(fig. 20). 

ISOTOPIC SIGNATURES: See Age Range above. 

FLUID INCLUSIONS: Fluid-inclusion-filling temperatures of 80-173 oc for ore-related sphalerite, dolomite, and calcite. 

Salinities (in weight percent NaCl equivalent) are for sphalerite, ~9, for dolomite, ~17, and for calcite, ~4 (Wenrich, 

1985; Wenrich and Sutphin, 1988). 

STRUCTURAL SETTING: All ore associated with solution-collapse breccia pipes. 

ORE DEPOSIT GEOMETRY: Orebodies develop in annular-ring structures and in the core (fig. 20). At Orphan Lode, 

ore bodies in core range from 15 to 60 min diameter and from 30 to 90 m high; annular-ring ore bodies are 5-20 m wide 

and a few tens of meters high, and extend variably part way around ring circumference (Chenoweth, 1988). 

ALTERATION: Characteristic bleaching by reduction (some extends locally outward into wall rocks as much as 30m); 

common carbonate recrystallization and calcification, local dolomitization and kaolinization, some weak silicification. 

Calcified rock extends outside boundary shears, completely surrounding the Orphan Lode pipe. Malachite, azurite, 

goethite, and other secondary minerals on surface outcrops of eroded pipes. 

EFFECT OF WEATHERING: Leaching of U and enrichment of Cu and V, particularly in those pipes deeply weathered. 

"Massive sulfide cap" apparently prevented oxidation prior to erosion and exposure. 

EFFECT OF MET AMORPHISM: Not applicable. 

GEOCHEMICAL SIGNATURES: Enrichment of Ag, As, Ba, Cd, Co, Cr, Cs, Cu, Hg, Mo, Ni, Pb, Sb, Se, Sr, U, V, Y, Zn, 

Zr, and REE; indicator elements are Ag, As, Co, Cu, Ni, Pb, and Zn (Wenrich, 1985). 

GEOPHYSICAL SIGNATURES: Electrical conductivity and magnetic properties of the pipes are significantly greater than 

for unbrecciated rocks; diagnostic differences in conductivity shown by scalar audiomagnetotelluric (AMT) and Efield telluric profile data for one pipe (Flanigan and others, 1986). Ground magnetometer surveys show subtle low 

magnetic values over several pipes (Van Gosen and Wenrich, 1989). 

SPATIAL EXPLORATION GUIDES: Collapse features recognized by concentrically inward-dipping beds, circular 

concave topography, circular patches of brecciated and (or) bleached or iron-stained rock (related to "massive sulfide 

cap''), and differences in vegetation. In well-exposed areas of the Marble Plateau, collapse breccia pipe densities are 

0.11 pipes per square kilometer. Marked tendency for pipes to occur in clusters as small as 3 km2 in diameter. The 

presence of one pipe indicates a high probability for other pipes nearby. 

OTHER EXPLORATION GUIDES: For a new area outside of the Grand Canyon region, a thick (>15m) flat-lying,karstforming limestone overlain by a thick sequence of predominantly carbonate-cemented sandstone and siltstone within 

a perpetually stable cratonic environment and a post-pipe formation volcanic source for uranium. Preexisting 

Mississippi Valley-type Cu-Co-Ni-Pb-Zn sulfide-rich ore may be required as a reductant for uranium deposition. 

OVERBURDEN: Favorable area on Coconino Plateau (fig. 20): depths to mineralized portion of pipes are 150-600 m. Area 

exposed on Esplanade surface (fig. 20): depths are 0-120 m. Additional cover by basalt, 0-100 m thick, around San 

Francisco and Mt. Floyd volcanic fields. Quaternary and Tertiary sediments, 0-50 m thick, cover a few areas. 

OTHER: Tectonic stability required for preservation. "Massive sulfide cap" prevented and delayed oxidation of some breccia 

pipe ores. Goethite possible pathfinder mineral for recognition of concealed pipe. 

34 
~') 

Model 32e-Con. 

I I 1-E-----Diameter of surface depression~, I 

I 

Chinle 

Formation 

~ (/) 

(/) 

~ 

a: Moenkopi 1-

Formation 

Kaibab Harrisburg Membe ___ __ 

Limestone Fossil Mountain Member 

Toroweap 

Formation 

z Coconino Sandstone ~ 

~ 

a: 

w 

a.. Hermit Shale 

a. Esplanade Sandstone ::l 

e 

C) 

I 

:...J z .>-~ 

(/)_ 

zz 

z~ 

LLJ> 

Cl. 

z Surprise Canyon 

~ Formation a.. (Mississippian) a.. 

(/) 

(/) 

u; Redwall Limestone (/) 

i 

I 

oz Temple Butte Limestone :>~ 

L.i.lz 

C::l 

f~ t~ 

[~ 

~ 

~ 

(i2[] 

Sandstone 

Conglomeratic sandstone 

Eolian sandstone 

Calcareous sandstone 

Gypsiferous sandstone 

EXPLANATION 

Silty sandstone 

Siltstone 

Claystone 

Limestone 

Argillaceous limestone 

-·-- .. 

Average thickness 

or range in thickness 

(in meters) 

·::.·~·-····.·· .. - .. 12Q-360 

Q-180 

12Q-215 

0-140 

Dolomite 

Gypsum 

Uranium ore 

Breccia-pipe fill, breccia 

derived from enclosed 

strata 

Figure 20. Schematic cross section of a solution-collapse breccia pipe in the Grand Canyon region, showing the general distribution of uranium ore within the pipe (stratigraphic section modified after Van Gosen 

and Wenrich, 1989). 

35 
Model 32e-Con. 

GRADE AND TONNAGE MODEL OF SOLUTION-COLLAPSE 

BRECCIA PIPE URANIUM DEPOSITS 

By Warren I. Finch, Charles T. Pierson, and Hoyt B. Sutphin 

COMMENTS All the deposits in this grade and tonnage compilation are from the Grand Canyon region of northwestern Arizona. 

36 

From the many mineralized solution-collapse breccia pipes in the region, we have chosen eight deposits that contain mostly 

primary, unoxidized minerals and have complete, reliable grade and tonnage data. Other mineralized breccia pipes are 

deeply eroded, strongly weathered, depleted in uranium, and enriched by supergene processes to minable grades of copper, 

vanadium, and other metals. These remnant deposits are not considered here to be a separate, distinct class of deposits. 

Furthermore, grade and tonnage data of these remnant deposits (Chenoweth, 1988) are too incomplete to graph 

meaningfully either separately or combined with the primary deposits. 

During the 1950-70 period when the Orphan Lode was mined, the cutoff grades were around 0.10 percent U 3 0 8• Few, 

if any, breccia pipes were mined in the 1970's. In the 1980's, the cutoff grade was 0.20-0.35 percent U30 8 for the remaining 

seven pipes. The average grade of the Orphan Lode ore mined in the early period was 0.43 percent U3

0 8 (Chenoweth, 1986), 

whereas ores mined from other pipes in the 1980's averaged about 0.65 percent U30 8 (Mathisen, 1987). The grade and 

tonnage data used to plot the graphs in figures 21 and 22 are based on premining reserves calculated at a cutoff grade of 

0.05 percent U30 8• Energy Fuels Nuclear, Inc., operators of all deposits but the Orphan Lode, kindly permitted the use of 

data from their properties. See appendix B for locality abbreviations. See introduction for explanation of the grade and 

tonnage model as shown in figures 21 and 22. 

0.9 

0.8 

C/) t: 0.7 

C/) 

0 

a_ 

w 0.6 

0 

u. 

~ 0.5 

0 

i= 

a: 0.4 

0 

a_ 

0 

g: 0.3 

0.2 

0.1 

Solution-collapse breccia pipe uranium 

.n-8 

1,600 

TONNAGE, IN MILLION METRIC TONS 

Figure 21. Tonnages of solution-collapse breccia pipe uranium deposits. 
Name 

0.9 

0.8 

en !::: 0.7 

en 

0 

c... 

w 0.6 

0 

u.. 

~ 0.5 

0 

i= 

0: 0.4 

0 

c... 

0 

g: 0.3 

0.2 

0.1 

Solution-collapse breccia pipe uranium 

11=8 

URANIUM-OXIDE GRADE, IN PERCENT 

Figure 22. Uranium-oxide grades of solution-collapse breccia pipe 

uranium deposits. 

DEPOSITS DEPOSITS 

Country Name 

Model 32e-Con. 

Country 

Canyon USAZ Kanab North USAZ 

HackNo. 1 USAZ Orphan Lode USAZ 

Hack No.2 USAZ Pigeon USAZ 

Hack No.3 USAZ Pinenut USAZ 

The scatter plot of the logarithms (to base 1 0) of grade and tonnage is shown in figure 23. This plot and the correlation 

coefficient of -0.122 suggest that the log-tonnage and log-grade are not correlated. Neither probability plots nor 

histograms of the grade and tonnage data demonstrate either normality or lognormality. Skewness is 0.13 for log -tonnages 

and -0.90 for log-grades. The mean tonnage and grade are 269,600 metric tons and 0.57 percent U3

0 8, with standard 

deviations of 157,370 metric tons and 0.07 percent U3

0 8, respectively. 

Trace-element contents of five of the eight pipes are shown in table 9. Because the selected samples were high graded, 

these data do not represent the average grade for a given deposit. Hence, grade curves cannot be constructed from the data. 

Nevertheless, they do show that the mean value of the elements As, Co, Cu, Ni, Pb, U, andZn are high locally within breccia 

pipe primary orebodies. Copper, vanadium, gold, and silver have been produced from some highly oxidized breccia pipe 

uranium ores (Chenoweth, 1986, 1988). 

37 
Model 32e-Con. 

38 

fz 

w 

() 

a: 

w 

-0.1 

a. -02 ~ . 

w 

0 

x 

0 

~ 

::> z -0.3 

<( 

a: 

::> 

8 

...J 

-0.4 

• 

-1.0 

Solution-collapse breccia pipe uranium 

• 

• 

• • 

• 

• 

• -0.8 -0.6 -0.4 

LOG URANIUM ORE TONNAGE, 

IN MILLION METRIC TONS 

-0.2 

Figure 23. Scatter plot of logarithms of average 

uranium-oxide grade vs. tonnage of uranium ore. 

Table 9. Summary statistics of chemical analyses 

of one selected sample from each of the five solution-collapse breccia pipe uranium deposits 

(based on analyses by Wenrich and Sutphin, 

1989, and their unpublished data) 

Element 

Ag------------------------

As ------------------------

B a------------------------

Cd------------------------

Ce ------------------------

Co------------------------

Cr ------------------------

Mean 

(ppm) 

34 

8,340 

139 

31 

102 

2,044 

51 

Cu------------------------ 11,440 

Fe------------------------ 4.71 

Ga------------------------ 21 

La------------------------ 17 

Li------------------------- 20 

Mo ----------------------- 403 

Ni ------------------------ 4, 760 

Ph------------------------ 2,978 

Sr------------------------- 3 72 

u ------------------------- 77,400 

v ------------------------- 121 

y ------------------------- 124 

Zn ------------------------ 9,584 

Standard deviation 

(ppm) 

22 

6,981 

109 

40 

94 

3,795 

68 

9,340 

3.71 

9 

7 

16 

312 

5,998 

2,042 

494 

65,569 

99 

112 

11,469 

1

Both the mean and standard deviation for Fe are in percent. 

, 

I 
Model34f 

DESCRIPTIVE MODEL OF OOLITIC IRONSTONES 

By J.B. Maynard1 and F.B. Van Houten2 

BRIEF DESCRIPTION 

SYNONYM: Clinton-type deposit, Minette-type deposit. 

DESCRIPTION: Beds rich in iron silicate and oxide minerals with distinctive oolitic texture deposited in shallow-shelf to 

intertidal, clastic-dominated environments. 

TYPICAL DEPOSITS: Wabana, Newfoundland (Ranger and others, 1984); Birmingham, Alabama (Simpson and Gray, 

1968); Lorraine, France and Luxembourg (Teyssen, 1984); southern Algeria (Guerrak, 1987); Cleveland, northeast 

England (Hallimond, 1925); Northampton Sand, England (Taylor, 1949). 

RELATIVE IMPORTANCE: Important source of Fe from 1850 to 1945. Declining world importance since then because of 

competition from Precambrian banded-iron formations. 

DISTINGUISHING FEATURES: Distinguished from banded-iron formations by absence of chert, presence of oolitic 

textures, and Al-bearing silicates. Distinguished from blackband ironstones by absence of primary siderite and presence 

of oolitic textures. 

COMMODITIES: Fe. 

OTHER COMMODITIES: Ocher. 

ASSOCIATED DEPOSIT TYPES (*suspected to be genetically related): None. 

REGIONAL GEOLOGIC ATTRIBUTES 

TECTONOSTRATIGRAPHIC SETTING: Craton margins, 40 percent; craton interiors, 25 percent; foreland basins, 20 

percent; exotic terranes, 15 percent. 

REGIONAL DEPOSITIONAL ENVIRONMENT: Shallow shelf, most typically close to the transition from nonmarine to 

marine environments. 

AGE RANGE: Phanerozoic, concentrated in the Ordovician to Devonian and Jurassic to Paleogene. A few Proterozoic 

examples. 

LOCAL GEOLOGIC ATTRIBUTES 

HOST ROCKS: Almost always clastic hosted at top of coarsening and shoaling-upward cycles (fig. 24). 

ASSOCIATED ROCKS: Standard vertical succession is black shale at base, followed by gray shale and siltstone, then by 

sandstone with graded bedding and hummocky cross-stratificiation suggesting tempestites, and finally by sandstone 

or oolitic ironstone with bipolar cross-stratification suggesting intertidal deposition. The association with black shale 

(Hallam and Bradshaw, 1979) is significant: 75 percent of well-developed Phanerozoic ironstones have an extensive 

black shale at the base of the shoaling cycle (VanHouten and Arthur, 1989). 

ORE MINERALOGY: Younger rocks: goethite+ berthierine (7-A chlorite). Older rocks: hematite+ chamosite (14-A 

chlorite). Siderite common as a replacement; locally, pyrite found as replacement (Maynard, 1986); occasionally, 

magnetite. 

GANGUE MINERALS: Quartz± calcite± dolomite± clay minerals; apatite (collophane) ubiquitous in small amounts. 

STRUCTURE AND ZONING: Rarely reported. Hematite cemented with Fe silicates to magnetite at Sierra Grande, Argentina 

(Leiding V., 1955). 

ORE CONTROLS: Three-quarters of deposits show strong control by position at the top of sedimentary cycle. Many of the 

larger deposits show features of tidally influenced deposition. 

1 University of Cincinnati, Cincinnati, Ohio. 2 Princeton University, Princeton, New Jersey. 

39 
Model 34f-Con. 

Q,) 

-u 

~ 

u 

Regression Siltstone, sandstone 

Shale 

..................... Condensed deposits i"~P ... ..,~;s~~~~... Hardground -'e~~~~~~~~ ... 

STlLLSTAND ;....~~~=---»~,.~ Oolitic ironstone ~..:-~·,.;..::...:~: ... ·······································~~~~~~~~~~; ..................... . 

Regression ~~~~~~~~~~~ Sil~rone, ~oosrone ~~i~jjii.l@~~(~J~ i:~~g·tr:t.~:~r.-r;~-~~i~~~~~: 

·::J~:.t.I~lli~~~~J:; .. ~-;r-;_: 

!lllllllllliil Black shale 

~{~t~{~~~~~{~~~~~ :,:.:.:~~.&o&o~~-- .. Jransgression ... Jt·~J'~·l.. ...... ~h~ ..................... . ~~~~~~~~~~ ... Condensed deposits $~~~~~~~~... Hardground .&'·~~··4:•••·-< STlLLSTAND ~&_~f Oolitic ironstone 

·:~J::i::7:7:"':f!.~/!l!l!tt. I I I I I I I I I I I I I I I I I I I I II 

-~-=:r-:;.::r-::r-::r-::r-:::-::::;:: 

:~~~~~~~~r~l~j~ Black shale 

shallow 

WATER DEPTH PROCESS LITHOLOGY 

Figure 24. Generalized stratigraphic model for oolitic ironstones. Vertical scale is variable; cycles may range from a few meters to as many as 300 m in thickness (modified 

after Van Houten and Bhattacharyya, 1982; Maynard, 1983). 

ISOTOPIC SIGNATURES: Siderite has light C, about -18 per mil; unknown for other minerals (Maynard, 1983). 

STRUCTURAL SETTING: Major deposits in undeformed to simply folded strata. Some Ordovician deposits on blocks 

complexly deformed by the Armorican (Hercynian) orogeny of Western Europe. 

ORE DEPOSIT GEOMETRY: Tabular bodies 2 to 5 m thick and 2 to 10 km across. 

ALTERATION: None relevant to mineralization. 

EFFECT OFWEA THE RING: Removes carbonate gangue and converts ferrous silicates to ferric oxides. Many older mining 

operations based on weathered ore; typically, workings less than 30m into outcrops. 

EFFECT OF MET AMORPHISM: Goethite converts to hematite above 80 oc (Hodych and others, 1984 ); hematite converts 

to magnetite under metamorphic conditions, but a few apparently unmetamorphosed deposits have magnetite 

(Devonian deposits of Libya). Berthierine converts to chamosite at 130-160 oc (lijima and Matsumoto, 1982). Most 

deposits unmetamorphosed. 

GEOCHEMICAL SIGNATURES: Only Fe. 

GEOPHYSICAL SIGNATURES: Marked positive gravity anomaly (1 mgal over 1-5 km) useful in delineating orebodies 

(Miller, 1983). Magnetite-bearing occurrences detectable by airborne magnetometer. 

OVERBURDEN: Most commonly clastic sedimentary rocks, from 0 to 500 min recently active mines. 

40 
Model 34f-Con. 

GRADE AND TONNAGE MODEL OF OOLITIC IRONSTONES 

By Greta J. Orris 

COMMENTS As with many deposit models, grade-tonnage information was not available for some of the well-known deposits. 

In addition, deposit definition (especially with regard to size information) is complicated by (1) the areally extensive 

bedded nature of the deposits, (2) the presence of multiple mineralized layers interbedded with country rock, and (3) the 

ambiguity of the reporting with regard to mining district or individual mine- or deposit-level information. Some deposits 

and (or) mines had tonnages or grades that were so disparate from the tentative grade-tonnage models that they could not 

be considered. This type of problem is often due to reporting error or deposit definition error. Several tonnages reported 

for English deposits were orders of magnitude too low and might represent reserves of mines working only parts oflarger 

deposits, and some U.S. and French deposits had tonnages so large that it is likely that several deposits were composited 

into single grade and tonnage figures. Lastly, it is impossible to claim that all possible sources of information were found 

and consulted. See appendix B for locality abbreviations. See introduction for explanation of the grade and tonnage model 

as shown in figures 25-28. 

Oolitic ironstones 

1.0 

0.9 

0.8 

(/') 0.7 !:::: 

(/') 

0 

c... 

w 0.6 

0 

LL 

0 0.5 z 

0 

f= 

a: 0.4 0 

c... 

0 

a: 0.3 c... 

0.2 

0.1 

6,300 

TONNAGE, IN MILLION METRIC TONS 

Figure 25. Tonnages of oolitic ironstone deposits. 

41 
Model 34f-Con. 

Figure 26. Iron grades of oolitic ironstone 

deposits. 

Figure 27. Silica grades of oolitic ironstone 

deposits. 

42 

Cl) 

1-

(/) 

0 

0... 

w 

0 

lL 

0 

z 

0 

f= 

a: 

0 

0... 

0 

a: 

0... 

Cl) 

1-

(/) 

0 

0... 

w 

0 

lL 

0 

z 

0 

f= 

a: 

0 

0... 

0 

a: 

0... 

Oolitic ironstones 

1.0 

• 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

0.0 USGS 

100 

IRON GRADE, IN PERCENT 

Oolitic ironstones 

1.0 

0.9 

0.8 

0.7 

0.6 

0.5 

0.4 

0.3 

0.2 

0.1 

100 

SILICA GRADE, IN PERCENT 
Model 34f-Con. 

Oolitic ironstones 

1.0 

n=40 

0.9 

0.8 

en 0.7 tCi5 

0 

c... • w 0.6 

0 

LL 

0 0.5 z 

0 

i= 

c: 0.4 0 

c... 

0 

c: 0.3 c... 

0.2 

0.1 

o.o USGS 

0.032 0.056 0.1 0.18 0.32 0.56 1.0 1.8 10.0 

PHOSPHATE GRADE, IN PERCENT 

Figure 28. Phosphate grades of oolitic ironstone deposits. 

DEPOSITS DEPOSITS 

Name Country Name Country 

AitAmar MRCO Langrial PKTN 

As wan EGPT Ljubija YUGO 

Birmingham USAL Ma-yu-kou CINA 

Boulhaut :MRCO Moncorvo PORT 

Camdag TRKY Musson-Halanzy BLGM 

Cho-lu CINA Nucice CZCL 

Cleveland UKEN Nurra ITLY 

Couthuin BLGM Ouarzemine :MRCO 

DemirHisar YUGO Pang-chia-pu CINA 

Frodingham -Scunthorpe UKEN Paz del Rio CLBA 

Gara Djebilet-Central area ALGR Salzgitter GRMY 

Gara Djebilet-East area ALGR San-cha-kou CINA 

Gara Djebilet-West area ALGR Settat MRCO 

Holoubkha CZCL Sierra Grande AGTN 

Hsin-yao CINA Sui-Ning CINA 

Imi n 'Tow·za MRCO Sumadija YUGO 

Isle of Raasay UKSC Tajmiste YUGO 

Jebel Ank TUNS Wabana CNNF 

~') Kerch USSR Yen-tung -shan CINA 

L' Hermitage-Lorge FRNC Zditz CZCL 

43 
Model36a.1 

GRADE AND TONNAGE MODEL OF CHUGACH-TYPE 

LOW-SULFIDE Au-QUARTZ VEINS 

By James D. Bliss 

COMMENTS Vein deposits in the Chugach National Forest, Alaska, have gross deposit characteristics that are consistent with 

the descriptive model for low-sulfide Au-quartz veins (Berger, 1986c). However, grade and tonnage data collected from 

these deposits during the preparation of the quantitative mineral resource assessment of undiscovered mineral deposits in 

the Chugach National Forest showed that the typical deposit has about half the tonnages and half the Au grades as those 

for low-sulfide Au-quartz veins elsewhere (Bliss, 1986). An important regional aspect of these deposits appears be the 

absence of association with batholithic-scale intrusive bodies, as is commonly found with low-sulfide Au-quartz vein 

deposits elsewhere. These low-sulfide Au-quartz veins are a subtype, here referred to as "Chugach-type low-sulfide Auquartz veins." They are located along faults and joints without a "consistent association with igneous activity" (Goldfarb 

and others, 1986). Major regional faults with mineralization are absent in the Chugach National Forest; such faults are 

important sites of mineralization for these low-sulfide Au-quartz vein deposits elsewhere. Fluid inclusion data for this area 

suggest that these deposits were deposited by low-salinity fluids generated by low-grade metamorphism (Goldfarb and 

others, 1986). The host rocks in the Chugach National Forest are metamorphosed to medium greenschist facies. A 

distinctive local characteristic of these deposits is that they exhibit much less wall-rock alteration (Goldfarb and others, 

1986) than low-sulfide Au-quartz veins elsewhere (Berger, 1986c). 

44 

Data for Chugach-type low-sulfide Au-quartz veins are from deposits in or adjacent to the Chugach National Forest 

and may bias the grade and tonnage model in ways not identified. Deposit definition was made using the same spatial rules 

concerning proximity of workings as in the model for low-sulfide Au-quartz veins (that is, properties within one mi of each 

other are aggregated) (Bliss, 1986). Data sources are from Jansons and others (1984) and the U.S. Geological Survey 

computerized data base on mineralized occurrences, prospects, and mines (the Minerals Resources Data System (MRDS)). 

In some cases, an estimate of tonnage was made using the technique developed by Bliss (1988). Significant correlation 

is present between Ag and Au grades (n=21, r=O. 77); this is also the case for low-sulfide Au-quartz vein deposits (Bliss, 

1986). More Ag grades were found in Chugach-type low sulfide Au-quartz vein deposits (70 percent) than in low sulfide 

Au-quartz vein deposits (10 percent) (Bliss, 1986). WhenAg grades are reported for Chugach-typelow-sulfideAu-quartz 

vein deposits, it is typically from 6 to 40 percent of Au grade compared with 11 to 89 percent for low-sulfide Au-quartz 

vein deposits. The data giving the ratio of Ag to Au grades between the main deposit type and the subtype are not 

significantly different at the 5 percent level (Mann-Whitney U Test). See appendix B for locality abbreviations. See 

introduction for explanation of the grade and tonnage model as shown in figures 29-31. 
0.9 

0.8 

~ 0.7 

U5 

0 

a... 

w 0.6 

0 

LL 

0 z 0.5 

0 

i= 

a: 0.4 

0 

a... 

0 

g: 0.3 

0.2 

0.1 

Chugach-type low-sulfide Au-quartz veins 

USGS o~00 .... 16----~-~--~--'----'------L.--~----L.--~--:1~.600 

0.9 

0.8 

~ 0.7 

U5 

0 

a... w 0.6 

0 

LL 

0 z 0.5 

0 

i= 

a: 0.4 

0 

a... 

0 

[ 0.3 

0.2 

0.1 

TONNAGE, IN TEN THOUSAND METRIC TONS 

Chugach-type low-sulfide Au-quartz veins 

11=29 

16 40 100 

GOLD GRADE, IN GRAMS PER METRIC TON 

Model 36a.1-Con. 

Figure 29. Tonnages of Chugach-type lowsulfide Au-quartz vein deposits. 

Figure 30. Gold grades of Chugach-type lowsulfide Au-quartz vein deposits. 

45 
Model 36a.1-Con. 

DEPOSITS 

Name 

Alaska Homes take 

Cameron-Johnson 

Cliff-Sealy 

Crown Point-Fall Creek 

Cube 

Donohue 

Downing 

Gold King 

Granite Lake (1) 

Granite Lake (2) 

Granite-Snowball 

Heaston-James 

Hercules-Big Four 

Hirshey-Carlson 

Hirshey-Lucky 

46 

Chugach-type low-sulfide Au-quartz veins 

1.0 

11=29 

0.9 

0.8 

en • 1- 0.7 

(j) 

0 

a.. 

w 0.6 

0 

LL 

0 0.5 z 

0 

i= 

a: 0.4 0 

a.. 

0 

a: 0.3 a.. 

0.2 

0.1 

0.0 USGS 

0.01 100 

SILVER GRADE, IN GRAMS PER METRIC TON 

Figure 31. Silver grades of Chugach-type low-sulfide Au-quartz vein 

deposits. 

DEPOSITS 

Country Name 

USAK Imperial 

USAK Kana 

USAK KenaiLu 

USAK Little Giant 

USAK Mayfield 

USAK McMillan 

USAK Mineral King 

USAK Monarch-Bahrenburg 

USAK Nearhouse 

USAK Primrose 

USAK Ramsay-Rutherford 

USAK Rough & Tough 

USAK Seward Bonanza 

USAK Tomboy-Lansing 

USAK 

, 

I 

Country 

USAK 

USAK 

USAK 

USAK 

USAK 

USAK 

USAK 

USAK 

USAK 

USAK 

USAK 

USAK 

USAK 

USAK 
Model38g 

DESCRIPTIVE MODEL OF LATERITE-SAPROLITE Au 

By Gregory E. McKelvey 

BRIEF DESCRIPTION 

SYNONYM: Eluvial gold placers (Boyle, 1979), Au-bearing saprolite (Becker, 1895). 

DESCRIPTION: Au disseminated in laterite and saprolite that developed under conditions of tropical weathering (fig. 32) over 

a wide variety of bedrock types but distal to known bedrock gold deposits. 

TYPICAL DEPOSITS: Boddington, Mt. Gibson, Edna May, Western Australia; Akaiwang, Arakaka, Guyana; Lumpkin and 

White Counties, Georgia. 

LATERITE 

-

'· M1 nere 1" 1 zed zones / 

Figure 32. Idealized cross section of laterite-saprolite Au deposit. Vertical scale is in 

terms of meters; horizontal scale is in terms of kilometers. 

47 
Model 38g-Con. 

DISTINGUISHING FEATURES: Residual and chemical enrichment of gold in tropical areas with laterites and bauxites. 

Deposit type develops under near-surface conditions of temperature and pressure, and unlike most gold placers it lacks 

significant detrital gold. Presence of laterite is essential precondition for deposit type. 

COMMODITIES: Au±Ag. 

OTHER COMMODITIES: Al, PGE, Fe, Sn, W. 

ASSOCIATED DEPOSIT TYPES (*suspected to be genetically related): *laterite-type bauxite, lateritic Ni, *alluvial AuPGE placers. All Au-bearing lodes may be found in the bedrock, including low-sulfide Au-quartz veins, Homestake 

Au, polymetallic replacement and vein deposits, kuroko or Cyprus massive sulfides, porphyry Cu, and rarely lithified 

placers (Boyle, 1987). By definition, lode mineral deposits should not be present directly under this deposit type. 

REGIONAL GEOLOGIC ATTRIBUTES 

TECTONOSTRATIGRAPHIC SETTING: Stable weathering zone commonly above greenstone belts and all other goldbearing terranes. 

REGIONAL DEPOSITIONAL ENVIRONMENT: Stable craton, prolonged weathering. If like laterite-type bauxite, 

deposits should occur commonly along erosional boundaries of old plateau remnants (Patterson, 1986). 

AGE RANGE: Cenozoic; late Oligocene to early Miocene in Western Australia (Monti,1987) 

LOCAL GEOLOGIC ATTRIBUTES 

HOST ROCKS: Regoliths, most are lateritic. Others enriched in aluminum (bauxite) (Boyle, 1979). Also, less frequently, 

deposits found in saprolites, as in the southern Appalachians (Becker, 1895). 

AS SOCIA TED ROCKS: Greenstones with Au-bearing veins and disseminations. Bedrock may contain various lode deposits 

and mineralized occurrences typical of stable craton areas (see Associated Deposit Types). Iron-formation or itabirite ' 

(Brazil). Other gold-bearing terranes. ~ 

ORE MINERALOGY: Finely divided Au. May be splendent, hackle, unworn, rough, and irregular in form. Nuggets are rare. 

No nuggets are found at Boddington but are identified at Edna May (Monti, 1987). Au as flakes, wire, and specks in 

canga(see Structure and Zoning). Au is between 1 and 10 J..L with an average of3-5 J..L at Boddington (Symons and others, 

1988). Ag and other metals usually higher than in alluvial Au placers (however, no Ag was detected in Au grains from 

Boddington (Monti, 1987), but small amounts ofCu (1.4 to 1.7 percent) and Fe (0.04 to 0.06 percent) were). Saprolitic 

Au very rough, with masses of wire Au (Becker, 1895). At the Boddington deposit, the following minerals are 

recognized: malachite, chalcocite, cuprite, chrysocolla, pyrite, chalcopyrite, arsenopyrite, native Cu, and electrum 

(Monti, 1987). 

GANGUE MINERALS: Fe, Al oxides and hydroxides, and Mn oxides. Limonite. Disintegrated bedrock fragments, including 

iron formation and kaolinite (Boyle, 1979). 

STRUCTURE AND ZONING: Mature laterites. Au mineralization may be localized in the laterite or displaced at depth into 

the underlying saprolite; mineralization in laterites likely to have same texture as that of laterite-type bauxite, which 

includes pisolitic, massive, nodular, and earthy (Patterson, 1986). Limonite-cemented fragments of iron formationcalled apanhoancango or canga in Brazil (Boyle, 1979). At the Boddington deposit, hematitic nodules, clay with 

Liesegang rings, and ferruginous and bauxiticlateritesoccurthatarelocallyindurated (Symon and others, 1988). Three 

broad mineralized levels (average 5 m thick) recognized at this deposit, with individual levels hosted by one or more 

of the following: ( 1) a 4- to 12-m-thick ferruginous zone consisting of a hardcap subzone and a B -subzone with nodular 

and rubbly clay; (2) a 20- to 100-m-thick clay zone; and (3) an up to 5-m-thick saprolite zone. Au found in pisoliths 

at Edna May but not at Boddington (Monti, 1987). 

ORE CONTROLS: Mature laterites. Bauxites and saprolites occur in areas where geomorphology allows sufficient drainage, 

so that oxidation is both extensive and deep1 to promote extensive leaching. Develops under conditions of strong 

chemical weathering with mean annual temperatures greater than approximately 10 oc and rainfall greater than 

1 Observed to 90 min Nigeria (Thomas, 1965) and to 500 min Hawaii (S.H. Patterson, written commun., 1978). 

48 
Model 38g-Con. 

approximately 140 em (Peltier, 1950). Deposition of gold at Boddington believed to be controlled by the position of 

the water table. Multiple mineralized horizons are products of fluctuations resulting from several climatic regimes 

(Monti, 1987). 

STRUCTURAL SETTING: Bedrocks sufficiently fractured and (or) faulted (or have other types of porosity) so that ground 

water is below weathered horizon. 

ORE DEPOSIT GEOMETRY: Blanketlike on flat terrains or fanlike on gentle slopes (Boyle, 1979). The area of the 

Boddington, deposit is 4.5 km2 with an average thickness of 35m. Deposits are roughly parallel to the land surface and 

have thicknesses of tens of meters. Pay streaks nonuniform and erratic (Boyle, 1979). Three mineralized zones separated 

by barren or weakly mineralized zones recognized at Boddington (Monti, 1987). At this deposit, gold is homogeneously 

distributed when mineralized zones are in laterites and erratic when in saprolites (Symons and others, 1988). 

TYPICAL ALTERATION/OTHER HALO DIMENSIONS: Iron oxide and clay mineralogy may indicate chemical 

enrichment. 

EFFECT OFWEA THERING: Main processes of Au concentration include residual enrichment of Au, chemical precipitation 

of Au, and a combination of both (Boyle, 1987). 

EFFECT OF METAMORPHISM: No metamorphic equivalents known. 

GEOCHEMICAL SIGNATURES: ±Al±Ga(ifcontained ina laterite-type oouxite) (Patterson, 1986). Au is signature for some 

but not all deposits. A study of enrichment/depletion of elements at Boddington shows that Sc is enriched with the Au, 

and that Fe, AI, Ga, As, Pb, and Sn are enriched as part of the ferruginous zone (Monti, 1987). 

GEOPHYSICAL SIGNATURES: Unknown. May be used to identify bedrock features associated with protore. Electrical 

properties of deposit may prove to be useful. Shallow seismic may be useful in deposit-shape determination. 

OTHER EXPLORATION GUIDES: Vegetation may be useful either in identifying areas of poor fertility or in biogeochemical 

exploration; oxide mineralogy may change systematically from background to adjacent and over the deposits. 

0 VERBURDEN: Mineralization in saprolite may have a cover of unmineralized laterite or a thin" A" horizon as at Boddington 

(Symons and others, 1988), which includes loose pisolites (maximum diameter of 2 em) with gibbsite (45 percent), 

goethite (20 percent), hematite (20 percent), and maghemite (Monti, 1987). 

OTHER: Dissected deposits with very fine gold (several microns) may not have been recognized in the past by placer miners. 

Some bauxites and laterites have been known to contain Au (Boyle, 1979). Deposit type should not include the 

weathered horizon of lode deposit types. 

49 
Model 38g-Con. 

GRADE AND TONNAGE MODEL OF LATERITE-SAPROLITE Au 

By James D. Bliss 

COMMENTS Deposits with data are few and likely subject to revision. Most of the data for laterite-saprolite Au deposits are 

from one area, and this may bias the model. Deposits are under active investigation and have the following qualifications: 

(1) data on deposit sizes and grades are for unworked deposits, (2) deposits may be underlain by unrecognized mineral 

deposits in the bedrocks, and (3) deposits may be placer deposits, not laterite-saprolite Au. One such deposit (Omai, 

Guyana) has residual mineralization at the surface and mineralization in the bedrock and is excluded in conformance with 

the descriptive model. The general pattern in the mining of mineral deposits is that the total tonnage (production plus 

reserves)continues to increase over a portion of the mine life. Therefore, deposit tonnages used in the model are very likely 

minimum values when compared with tonnages at deposit exhaustion. See appendix B for locality abbreviations. See 

introduction for explanation of the grade and tonnage model as shown in figures 33 and 34. 

Saprolite-laterite Au 

1.0 

1'1=9 

0.9 

0.8 

CJ) 

1- 0.7 

u; 

0 

a.. 

w 0.6 

0 

LL 

0 

z 0.5 

0 

i= 

a: 0.4 0 

a.. 

0 

a: 0.3 a.. 

0.2 

0.1 

o.o USGS 

0.0016 0.0063 0.025 0.1 0.4 1.6 6.3 25 100 400 1,600 

TONNAGE, IN MILLION METRIC TONS 

Figure 33. Tonnages of laterite-saprolite Au deposits. 

50 
Model38g-Con. 

Saprolite-laterite Au 

1.0 

0.9 

0.8 

en 0.7 1-

(i) 

0 

a.. 

w 0.6 

0 

LL 

0 0.5 z 

0 

i= 

c: 0.4 0 

a.. 

0 

c: 0.3 a.. 

GOLD GRADE, IN GRAMS PER METRIC TON 

Figure 34. Gold grades of laterite-saprolite Au deposits. 

DEPOSITS DEPOSITS 

~ Country Name Country 

Akaiwang GUYN Millionaire GUYN 

Arakaka GUYN Mt.Gibson AUWA 

Baramita GUYN Royal Hill Gold SRNM 

Boddington AUWA Tassawine GUYN 

B ullabuling AUWA 

51 
Preliminary Descriptive Deposit Model for 

Detachment-Fault-Related Mineralization 

By Keith R. Long 

INTRODUCTION 

Mineralization related to detachment faulting has 

only recently been recognized as a distinct deposit type, 

even though such deposits have been mined since the 

1860's. These deposits have characteristic mineral assemblages, alteration patterns, ore fluid types, and structural 

controls that differ considerably from those of other deposit types found in the Basin and Range province of the 

Western United States. However, detachment-fault-related 

mineralization is not widely known, having been described 

but twice in widely circulated journals (Spencer and Welty, 1986; Roddy and others, 1988); most of the detailed 

studies have appeared as publications of the Arizona Geological Survey and the Arizona Geological Society. 

Awareness of the unique character of these deposits 

has been hampered by confusion with other types of epithermal mineralization that may or may not occur near a 

low-angle or detachment fault, such as the Cyclopic deposit in northwest Arizona (Myers and Smith, 1986) or the 

Mesquite deposit in southeastern California (Manske and 

others, 1988). This discussion sets out the distinguishing 

characteristics of detachment-fault-related mineralization 

vis-a-vis other types of epithermal mineralization in theregion and provides a justification for the new deposit model 

presented (K.R. Long, this volume). This deposit model is 

considered preliminary because this deposit type has yet to 

be fully investigated and has, thus far, only been recognized in a detachment-faulted terrane encompassing parts 

of west-central Arizona, southeastern California, and 

southernmost Nevada (fig. 35). 

DETACHMENT -FAULT -RELATED 

MINERALIZATION 

Detachment faults are low-angle (up to 30°) normal 

faults of regional extent that have accommodated significant regional extension by upward movement of the footwall (lower-plate) producing horizontal displacements on 

the order of tens of kilometers. Common features of these 

faults are supracrustal rocks in the upper-plate on top of 

52 

lower-plate rocks that were once at middle and lower 

crustal depths, mylonitization in lower-plate rocks that are 

cut by the brittle detachment fault, and listric and planar 

normal faults bounding half-graben basins in the upperplate (Davis and Lister, 1988). 

The detachment fault and structurally higher normal 

faults locally host massive replacements, stockworks, and 

veins of iron and copper oxides with locally abundant sulfides, veins of barite and (or) fluorite, and veins of manganese oxides (Spencer and Welty, 1986; fig. 36). Bedded 

manganese oxides occur in sedimentary rocks deposited in 

the half-graben basins and are generally associated with 

fault veins of manganese oxides. These bedded manganese 

deposits should be described separately as another model 

(lacustrine manganese). Intense chloritic alteration of footwall mylonitic rocks and potassium feldspar replacement 

of upper-plate rocks are common alteration types that are 

not always accompanied by mineralization. 

This mineralization is termed detachment fault related not simply because it is strongly controlled by detachment-fault structures, but also because it is apparently related to the formation of detachment faults themselves 

(Roddy and others, 1988). Early chloritic alteration and associated sulfide mineralization appears to result from retrograde metamorphism as hot lower-plate rocks are brought 

up to shallower depths. Potassium feldspar alteration and 

oxide mineralization appear to be related to the upward 

circulation of saline brines derived from syntectonic basins 

along the detachment fault into more steeply dipping upper-plate normal faults. This fluid movement may have 

been driven by heat derived either from lower-plate rocks 

or from syntectonic microdiorite to rhyolite intrusives 

(Reynolds and Lister, 1987). 

DISTINGUISHING CHARACTERISTICS OF 

DETACHMENT-FAULT -RELATED 

Ml N ERALIZA TION 

Features of detachment-fault-related mineralization 

that distinguish it from other deposit types are listed below. Further details are available in Spencer and Welty 

, 

I 
116 

36 

34'' 

~--------------------------------------------, 

I I 

NEVADA I I 

I \ I 

I 

,~-..""~'! \ 

..:v' I 

\ 

I ARIZONA 

CALIFORNIA~ ~' Ql~ ~ 

( ~ ~ ol ),? 0 

l<~ ) :1 

~ \ 

I 

_ _; / 

--·-----l 

''-........,,......__, ............... 

........................... 

............... ............... 

........................... I ............... .... I ........... __________________ __ 0 100 KILOMETERS 

EXPLANATION 

-"--.._ Detachment fault 

0 Known detachment-fault-related deposits 

Figure 35. Major detachment faults and detachment-fault-related mineral deposits in Arizona, southeastern California, and 

southernmost Nevada. 

53 
(1986), Roddy and others (1988), and Spencer and 

Reynolds (1989). 

equivalent weight percent NaCl), compatible with 

precipitation from connate brines. Fluid inclusions 

from barite-fluorite veins have lower homogenization temperatures (90 to 200 °C) and are somewhat 

less saline (6 to 20 equivalent weight percent NaCI), 

compatible with precipitation from variably cooled 

and diluted connate brines. 

54 

1. Deposits are controlled by structures formed during 

detachment faulting. These include the low-angle, 

detachment-fault system, high-angle faults in the 

lower-plate just below the detachment fault, and 

low- to high-angle normal faults in the upper-plate. 

2. Deposits are often brecciated or deformed by movement along or above the detachment fault. 

3. Chlorite-epidote-calcite alteration occurs along and 

below the detachment fault. These altered zones 

sometimes contain base-metal sulfides and barite. 

4. There is massive potassium feldspar replacement of 

upper-plate rocks. This alteration appears to generally precede ore formation and is not always spatially 

associated with mineralization. 

5. Weak sericite-silica alteration of wall rock is sometimes present around barite-fluorite veins. 

6. Most mineralization consists of iron and copper oxides, principally specular to earthy hematite and chrysocolla. Common gangue minerals are chalcedonic to 

amethystine quartz, ferrous to manganiferous calcite, 

barite, fluorite and manganese oxides. Distal baritefluorite veins consist of variable proportions of barite, 

fluorite, and manganese oxides. Common gangue minerals are quartz and manganiferous calcite. 

7. Fluid inclusions have moderate homogenization 

temperatures (150 to 350 °C) and salinities (10 to 23 

8. Host rocks are enriched in Cu, Pb, Zn, Au, Ag, and 

Ba and are depleted in Mn, Sr, Ni, and Rb. Elements 

characteristic of epithermal environments, such as 

As, Sb, Hg, and Tl, occur in very low, backgroundlevel concentrations. 

DEPOSIT TYPES COMMONLY CONFUSED 

WITH DETACHMENT-FAULT-RELATED 

MINERALIZATION 

Epithermal gold-silver deposits that occur along or 

near low-angle faults might be mistaken for detachmentfault-related mineralization. Several possible cases can be 

identified: 

1. Epithermal deposits found in metamorphic rocks (for 

example, Mesquite, California; Manske and others, 

1988). 

2. Epithermal deposits that are overprinted by younger 

detachment-fault-related mineralization (for example, 

Cyclopic, Arizona; Myers and Smith, 1986). 

EXPLANATION 

CiJ Syntectonic basin fill 

a Upper-plate sedimentary a and igneous rocks 

[ili] Lower-plate metamorphic rocks 

~Mylonite 

Mineralization 

Fault 

Cu-Fe-Pb-Zn-Ag-Au replacement 

and veins 

Ba-F veins 

Mn bedded and veins 

Figure 36. Schematic diagram (not to scale) showing structural position of detachment-fault-related polymetallic mineralization, Ba-F-Mn veins, and lacustrine manganese mineralization in detachment-faulted terranes. 
3. Epithermal deposits that overprint detachment-faultrelated mineralization or that were emplaced during 

detachment faulting (for example, Bullfrog, Nevada; 

Jorgeson and others, 1989). 

4. Epithermal deposits that are significantly younger 

than detachment faulting but are controlled by 

detachment-fault structures (no known examples in 

the published literature). 

Epithermal deposits can be distinguished from detachment-fault-related deposits by their characteristic ore 

mineralogy, alteration minerals and patterns, geochemical 

signatures, and fluid-inclusion compositions, as described 

in the deposit model for hot spring Au-Ag (Berger, 

1986b). Principal distinguishing characteristics are the 

following: 

1. Ore mineralogy consists of base- and precious-metal 

sulfides with few or no primary oxide minerals. 

Gangue quartz is not usually amethystine, and 

gangue calcite is poor in iron and manganese. 

2. Extensive propylitic and (or) argillic alteration of upper-·plate host rocks is observed with only local potassic alteration. 

3. Low-salinity ( <6 equivalent weight percent NaCl), 

moderate homogenization temperature (200 to 

300 °C) fluid inclusions are observed. 

4. Anomalous concentrations of the elements As, Sb, 

Hg, and Tl, which are characteristic of epithermal 

deposits, are present. 

SIZES AND GRADES OF DEPOSITS 

Available data on sizes and grades of detachmentfault-related mineral deposits consist mostly of production 

statistics originally collected by the U.S. Bureau of Mines 

and reported by the Arizona Geological Survey (Keith and 

others, 1983; Spencer and Welty, 1989). The only reserve 

data available are for recently explored deposits, such as 

Copperstone, Arizona (Spencer and others, 1988). Attempts 

to model tonnages and grades for detachment-fault-related 

polymetallic deposits using cumulative production data (table 1 0) were not successful. Few of these deposits produced all of the metals that occur in this deposit type, making it difficult to model deposit grades. In fact, indications 

are that there may be two subtypes of detachment-faultrelated mineralization-a Cu-Au type and a Pb-Zn-Ag 

type-but further research is required to confirm this. 

In any case, grade and tonnage models based on the 

production data listed in table 10 would not give an accurate indication of the range in sizes and grades of these 

deposits that could be expected to be encountered in a modem exploration program. Not only were not all metals recovered, but also many of these ores were concentrated in 

part by hand. In hand sorting, a large quantity of waste is 

typically rejected prior to sending ore to the concentrator, 

and these rejects are not always included in recorded production tonnages. Thus, the grades computed from production statistics are not likely representative of the true grade 

of the ore mined. Further, these were underground mines; 

thus, in comparison with the tonnages and grades that might 

be estimated for a modem open-pit operation, these older 

orebodies were smaller in size and higher in grade. 

A better sense of the potential size and grade of 

these deposits is indicated by recently reported reserves for 

deposits that have been excluded from table 10 as a result 

of their lack of production history. These are Copperstone 

(Spencer and others, 1988), a recent producer with reserves of 4.2 million short tons of 0.077 troy ounce per ton 

Au ore as of December 31, 1988, having produced 62,800 

troy ounces Au prior to that date (Cyprus Gold Co., 1989); 

and Newsboy, a recent discovery in Arizona, with reserves 

of 1.5 million short tons of 0.045 troy ounce per ton ore 

(H. Dummett, oral commun., 1989). 

A number of deposits have been excluded from table 

10 because their classification as detachment-fault-related 

deposits is controversial. These include Picacho, California 

(Van Nort and Harris, 1984), and Silver, Arizona (Bradley, 

1986). 

55 
Table 10. Grades and tonnages for detachment-fault-related polymetallic deposits 

[Tonnages in short tons; copper, lead, and zinc grades in percent; silver and gold grades in troy ounces per short ton. Country and sate abbreviations 

explained in app. B) r 

Deposit Country Tonnage Copper Lead Zinc Silver Gold Source 1 

grade grade grade grade grade 

Alamo-Bluebell---------------- USAZ 692 2.80 1.10 .47 0.12 2 

Artillery Peak------------------- USAZ 500 1.30 1.20 1 

Bullard -------------------------- USAZ 17,000 .35 .21 

Cienaga-------------------------- USAZ 19,092 4.50 .08 .63 2 

Clara----------------------------- USAZ 49,728 4.70 .03 2 

Cleopatra-Cleopatra----------- USAZ 14,744 1.50 .23 .11 2 

Cleopatra-Kimble ------------- USAZ 4,482 .30 .03 .01 2 

Cleopatra-Silverfield ---------- USAZ 863 .90 .03 9.50 .06 2 

Harquahala (Eastern) --------- USAZ 21,000 .14 .35 .13 1 

Lead Pill ------------------------ USAZ 1,451 .96 13.90 1.50 .36 2 

Mammon------------------------ USAZ 841 5.20 .17 .07 2 

Midway-Battleship ----------- USAZ 15 4.00 .07 2 

Midway-GreenStreak--------- USAZ 189 1.30 .11 .20 2 

Midway-Mammoth ----------- USAZ 10 16.30 1.30 .80 2 

Moon Mountains -------------- USAZ 300 .33 2.70 

Northern Plomosa ------------- USAZ 7,500 2.30 .16 .93 .67 

Osborne------------------------- USAZ 86,000 .79 4.50 2.30 .15 1 

Owens--------------------------- USAZ 792 .11 3.90 13.00 .13 2 

Picacho-------------------------- USAZ 100 1.20 1.00 

Planet-Mineral Hill------------ USAZ 970,756 .68 2 

Planet-Planet------------------- USAZ 39,015 8.00 .01 .01 2 

Pride----------------------------- USAZ 38 .03 .16 2.00 2 

Rawhide------------------------- USAZ 708 .74 18.4 1.60 11.50 .05 2 

Salt River Mountains --------- USAZ 15,000 .09 .33 .47 1 

Swansea------------------------- USAZ 544,918 2.40 .06 2 

Whipple------------------------- USCA 5,000 2.30 .01 1.90 .26 3 

1

Sources: 1 (Keith and others, 1983), 2 (Spencer and Reynolds, 1989), and 3 (Spencer and Welty, 1986). 

56 
Model40a 

DESCRIPTIVE MODEL OF DETACHMENT~FAULT-RELATED POLYMETALLIC DEPOSITS 

By Keith R. Long 

BRIEF DESCRIPTION 

SYNONYM: Detachment-fault-related gold, flat-fault gold. 

DESCRIPTION: Massive replacements, stockworks, and veins of iron and copper oxides and locally sulfides along 

detachment-fault structures. These deposits sometimes contain economic concentrations of gold and silver. Distal veins 

of quartz-barite-fluorite-Mn oxides emplaced along high -angle faults in the upper plate of detachment-faulted terranes. 

GENERAL REFERENCE: Wilkins and others (1986). 

TYPICAL DEPOSITS: Bullard (Roddy and others, 1988), Copperstone (Spencer and others, 1988), Osborne (Allen, 1985), 

Planet (Lehman and Spencer, 1989), Harris (Roddy and others, 1988), Tiger Wash (Allen, 1985). 

COMMODITIES: Cu +Au+ Ag ± Pb ± Zn. 

OTHER COMMODITIES: Fe-Ba-F-Mn-Mo-V. 

ASSOCIATED DEPOSIT TYPES (*suspected to be genetically related): *Lacustrine Mn. 

REGIONAL GEOLOGIC ATTRIBUTES 

TECTONOSTRATIGRAPHIC SETTING: Extensional terranes characterized by regional detachment faulting. 

REGIONAL DEPOSITIONAL ENVIRONMENT: Half-graben mountain ranges and hydrographically closed basins that 

formed syntectonically with extensional deformation above detachment faults. 

AGE RANGE: Known deposits range from middle to late Tertiary in age. 

LOCAL GEOLOGIC ATTRIBUTES 

HOST ROCKS: (1) Lower-plate mylonitic rocks, chlorite breccias, and structurally emplaced slivers ofupper-platerocks. (2) 

Upper-plate Paleozoic to Mesozoic (meta)sedimentary and (meta)volcanic rocks, Mesozoic to early Tertiary felsic 

intrusive rocks, middle to late Tertiary mafic to intermediate lavas, silicic tuffs, and sedimentary rocks deposited in 

alluvial fan, fluvial, and saline lake environments. 

AS SOCIA TED ROCKS: Syn- to posttectonic alkali basalts, microdiorite dikes, and sedimentary rocks deposited in halfgraben basins. 

ORE MINERALOGY: Specular and earthy hematite, chrysocolla, and gold or clectrum. Locally abundant chalcopyrite and 

other copper sulfides. Rare galena, sphalerite, and tetrahedrite. Sulfides accompany chloritic alteration in early-stage 

mineralization along and below detachment fault. Quartz-hematite-calcite-chrysocolla mineralization follows along 

and above detachment fault. Late-stage quartz-barite-fluorite-manganese oxide veins with locally abundant copper 

oxides, cerargyrite, argentite, gold, and hematite occur above detachment fault. 

GANGUE MINERALS: Quartz (sometimes chalcedonic or amethystine), calcite (often ferrous and (or) manganiferous), 

barite, fluorite, and manganese oxides. Locally abundant pyrite, jasperoid, gypsum, and clays. 

ZONING: Intensity of mineralization and alteration decreases away from detachment fault. Many districts zoned from 

polymetallic deposits outward to Ba-F-Mn veins. Mineralization tends to be base metal-rich and precious metal-poor 

near the detachment fault but precious metal-rich/base metal-poor away from the detachment fault. 

ORECONTROLS:Depositscommonlylocatedaboveaxisorflanksofsynformalstructuresinunderlyingdetachmentsurface. 

Orebodies are localized along high-angle fault zones below the detachment fault, along the detachment fault, and in 

high-angle, sometimes listric, normal faults in the upper plate. Gold is often associated with local silica flooding and 

amethystine quartz veins in brittle, fractured upper-plate rocks. Massive specularite replacements and chrysocolla veins 

occur in reactive calcareous units in both the upper and lower plates. 

ISOTOPIC SIGNATURES: Quartz associated with oxide ore minerals has6to 8 permillo 180,and that associated with sulfide 

ore minerals has 10 to 12 per mill o 180. Calcite associated with oxide ore minerals has 4 per mill o 180 and -4 to --6 

per mill o 13C PDB. K-metasomatizcd rock has lower o 180 than unaltered rock by 2 to 4 per mill. 

57 
Model 40a-Con. 

FLUID INCLUSIONS: In quartz, calcite and barite associated with sulfide ore homogenization temperatures are higher (220 

to 350 °C) than those associated with oxide ore (150 to 350 °C). Salinities, however, are similar at 10 to 23 equivalent 

weight percent NaCl. These fluids are thought to be saline brines derived from syntectonic, hydrographically closed, 

arid basins. Quartz in distal Ba-F-Mn veins have low-temperature (90 to 200 °C) and saline (6 to 20 weight percent 

equivalent NaCl) fluid inclusions. 

STRUCTURAL SETTING: Local flexures of a regional detachment fault with strong development of upper-plate, high-angle, 

listric and planar normal faults. 

ORE DEPOSIT GEOMETRY: (1) Narrow fracture and fault fillings that are 3 em to 12m in width with strike lengths of30 

to 2,000 m. (2) Irregular, pod-shaped massive replacements of reactive lithologies up to 900 m long, 100 m wide and 

3 to 30m thick. (4) Pods and anastomosing veins along low-anglefaults. (5) Veinletsand breccia clasts in fault breccia. 

ALTERATION: Wall rock dependent. Distinct alteration suites are observed: ( 1) Pre-ore to early chloritic (chlorite-epidotehematite) alteration oflower-plate mylonites and fault breccias, sometimes with associated quartz-pyrite-chalcopyrite±galena mineralization. (2) Pre-ore to early K-metasomatism of upper-plate volcanic rocks. Mafic rocks are 

converted into K-feldspar-hematite-calcite-chlorite-epidote rocks, and silicic rocks are converted into K-feldsparhematite-quartz rocks. (3) Pre-ore to early massive carbonate replacement of carbonate rocks. ( 4) Propylitic (chloritecalcite-epidote-sericite-clay) alteration envelopes around veins hosted by mafic rocks. Quartz-chrysocolla veins often 

have clay selvages. (5) Weak sericite-silica-dolomite envelopes around Ba-F-Mn veins in calcareous rocks. 

TYPICAL ALTERATION/OTHER HALO DIMENSIONS: (1) Chloritic alteration may extend from the top of the 

detachment fault down to 300 m below the detachment fault. (2) K -metasomatism may extend more than 2 km above 

the detachment fault in zones more than 10 km in extent. (3) Massive carbonate replacements range up to 900 min 

length, 100m wide, and about 30m thick. (4) Propylitic alteration halos are narrow, up to a few centimeters around 

veins and fracture fillings. 

EFFECT OF WEATHERING: Most ore consists of primary oxides. Locally abundant sulfides may be oxidized. 

EFFECT OF METAMORPHISM: Metamorphosed deposits are not known. 

GEOCHEMICAL SIGNATURES: Host rocks are enriched in Cu, Pb, Zn, Au, Ag, and Ba and depleted in Mn, Sr, Ni, and 

Rb. As, Sb, Hg, and Tl are also very low. 

GEOPHYSICAL SIGNATURES: There may be a resistivity contrast between oxide ores along and above the detachment 

fault and the mylonite zone beneath the detachment fault. Silica flooded zones may have high resistivity. Massive 

hematite ore bodies may produce a magnetic dipole anomaly. Shallow reflection seismic might detect detachment-fault 

structures. 

OTHER EXPLORATION GUIDES: Conodont alteration of upper-platePaleozoic sediments may serve as a guide to regional 

paleo-heat flow related to fluid movement along and above detachment faults. 

OVERBURDEN: Variable, owing to differing degrees of uplift along half-graben structures and regional warps. Polymetallic 

deposits are thought to have formed at a depth of 1 to 3 km (Spencer and Welty, 1986), and Ba-F-Mn veins at a depth 

of 0.5 km (Allen, 1985). 

58 
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61 
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Geological Society Digest, v. 16, p. 108-117. 
Appendix A. Classification of deposit models by lithologic-tectonic environment 

[Partal list of table 1 of Cox and Singer (1986); only applicable parts and modifications given. Some deposit-type numbers have been 

previously assigned for industrial mineral deposit types (G.J. Orris, written commun., May 1990), which has affected the numbers 

given here. *, indicates that model is not included in this bulletin] 

Deposit environment Model No. 

Mafic and ultramafic intrusions 

C. Alakaline intrusions in stable areas 

Carbonatite.. ... ... ..... ... .. ... ...... .. ... ..... ... ...... .. ........ ... ... ... .. ...... .. ...... ... ..... ... .. ... ... ... .. ... ... .. ...... ... .. ...... .. ... ... ..... ... ... .. .. 10 

(Thorium-rare-earth veins)................................................................................................................................. (11d) 

Alkaline complexes............................................................................................................................ 11 

Thorium-rare-earthveins.................................................................................................... 11d 

Felsic intrusions 

E. Porphyroaphanitic intrusions present 

Other felsic and mafic rocks including alkalic 

W allrocks are calcareous 

Deposits far from contact 

DistaldisseminatedAg-Au................................................................................ 19c 

Extrusive rocks 

G. Felsic-mafic extrusive rocks 

Subaerial 

Marine 

Deposits mainly within volcanic rocks 

Hot-spring Au-Ag............................................................................... ............ ............. ...... 25a 

Deposits in older calcareous rocks 

Sedimentary-hostedAul.................................................................................................... 26a 

Sierran kuroko massive sulfide.......................................................................................................... 28a.1 

Sedimentary rocks 

I. Carbonate rocks 

No associated igneous rocks 

Solution-collapse breccia pipe U ............................................................. .......................................... 32e 

J. Chemical sediments 

Shelf 

Oolitic ironstones............................................................................................................................... 34f 

Regionally metamorphosed rocks 

K. Derived mainly from eugeosynclinal rocks 

Chugach-typelow-sulfide Au-quartzvein................................................. ................. ............... ... .. ... 36a.1 

Surficial and unconformity related 

M. Residual 

Laterite-saproliteAu.......................................................................................................................................... 38g 

N. Depositional 

(Laterite-saproliteAu)........................................................................................................................................ (38g) 

Regional geologic structures 

0. Extended terranes 

Detachment fault-related polymetallic deposits................................................................................................ 40a 

LacustrineMn.................................................................................................................................................... 40b* 

1 Note name mange from "Carbonate-hosted Au-Ag" fotm.d in Cox and Singer (1986); other changes described in model text. 

63 
Appendix B. Locality abbreviations 

[Some abbreviations are from Singer and Cox (1986, app. A); some are new] 

AGTN 

ALGR 

AUWA 

CINA 

BLGM 

CZCL 

CLBA 

CNBC 

CNNF 

EGPT 

FRNC 

GRMY 

GUYN 

ITLY 

MRCO 

MXCO 

PERU 

PORT 

PKTN 

Argentina 

Algeria 

Australia, Western Australia 

China 

Belgium 

Czechoslovakia 

Colombia 

Canada, British Columbia 

Canada, Newfoundland 

Egypt 

France 

Germany 

Guyana 

Italy 

Morocco 

Mexico 

Peru 

Portugal 

Pakistan 

SRNM 

TRKY 

TUNS 

YUGO 

UKEN 

UKSC 

USAL 

USAK 

USAZ 

USCA 

us co 

USID 

USMT 

USNM 

USNV 

USSR 

USUT 

USWY 

Suriname 

Turkey 

Tunisia 

Yugoslavia 

United Kingdom, England 

United Kingdom, Scotland 

United States, Alabama 

United States, Alaska 

United States, Arizona 

United States, California 

United States, Colorado 

United States, Idaho 

United States, Montana 

United States, New Mexico 

United States, Nevada 

Union of Soviet Socialist Republics 

United States, Utah 

United States, Wyoming 

Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models 

64 

Findings 

Geologic-Ages 

Precambrian 

Archean 

Proterozoic 

Phanerozoic 

Paleozoic 

Mesozoic 

Cenozoic 

Cambrian 

Ordovician 

Silurian 

Devonian 

Carboniferous 

Mississippian 

Pennsylvanian 

Permian 

Triassic 

Jurassic 

Cretaceous 

Tertiary 

Paleogene 

Paleocene 

Eocene 

Oligocene 

Neogene 

Miocene 

Pliocene 

Quaternary 

Holocene 

Pleistocene 

, 

I 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

Rock-Types 

Igneous 

Plutonic 

Felsic-plutonic 

Granite 

Alas kite 

Leucogranite 

Muscovite-leucogranite 

Biotite-leucogranite 

Granulite 

Plagiogranite 

Trondhjemite 

Alkali -granite 

Alkali-feldspar-granite 

Chamockite 

Monzogranite 

Granodiorite 

Tonalite 

Alkali -quartz-syenite 

Quartz-syenite 

Quartz-monzonite 

Monzonite 

Syenite 

Syenite-porphyry 

Nepheline-syenite 

Larvikite 

Naujaite 

Nordmarkite 

Shonkinite 

Nephelinite 

Intermediate-plutonic 

Quartz-monzodiorite 

Quartz-monzogabbro 

Quartz-diorite 

Diorite 

Ijolite 

Diabase 

Mafic-plutonic 

Gabbro 

Ferrodiorite 

Ferro gabbro 

Eucrite 

Essexite 

Troctolite 

Olivine-gabbro 

Gabbro-norite 

Norite 

Hornblende-gabbro 

Jutunite 

Picritic-gabbro 

J acupirangite 

Ultramafic-plutonic 

Dunite 

Pyroxenite 

Websterite 

Homblende-clinopyroxenite 

Hornblende-magnetite-clinopyroxenite 

Magnetite-hornblende-pyroxenite 

65 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

66 

Rock-Types-Continued 

Igneous-Continued 

Plutonic--Continued 

Ultramafic-plutonic-Continued 

Peridotite 

Volcanic 

Lherzolite 

Harzburgite 

Kimberlite 

Wehrlite 

Chromitite 

Zoned-ultramafic 

Other-plutonic 

Anorthosite 

Andesine-anorthosite 

Volcanic-rocks 

Felsic-volcanic-rocks 

Alkali-rhyolite 

Alkali-feldspar-rhyolite 

Quartz-trachyte 

Quartz-latite 

Rhyolite 

Rhyodacite 

Dacite 

Rhyodacite 

Mafic-volcanic-rocks 

Andesite 

Tholeiitic-basalt 

Trachyte 

Latite 

Quartz-latite 

Basalt 

Shoshonite 

Phonolite 

Alkaline-volcanic-rocks 

Other-volcanic 

Ignimbrite 

Komatiite 

Tephra 

Tuff 

Andesitic-tuff 

Tuff-breccia 

Tholeiitic-tuff 

Tuffite 

Volcanic-breccia 

Vent-breccia 

Volcaniclastic-rocks 

Calc-alkaline-pyroclastics 

Flows 

Siliceous-sinter 

Agglomerate 

Hypabyssal 

Lamprophyre 

Monchiquite 

Vogesite 

Leucite-lamproite 

Olivine-lamproite 

Diabase 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

Rock-Types-Continued 

Igneous-Continued 

Hypabyssal-Continued 

Picrite 

Picrite-porphyrites 

Felsic-hypabyssal 

Aplite 

Granophyre 

Felsic-dikes 

Quartz-porphyry 

Granite-porphyry 

·Other-igneous-rocks 

Sedimentary 

Pelites 

Siltites 

Arenites 

Carbonatite 

Anierite-carbonatite 

Sovite 

Melilite 

Diabase 

Pegmatite 

Migmatite 

Ophiolite 

Mudstone 

Shale 

Clay 

Calcareous-shale 

Siliceous-shale 

Carbonaceous-shale 

Black-shale 

Gray-shale 

Green -shale 

Pyritic-shale 

Claystone 

Carbonaceous-pelites 

Siltite 

Siltstone 

Sand 

Sandstone 

Graywacke 

Quartzite 

Grit 

Red-beds 

Arkose 

Feldspathic-sandstone 

Arkose 

Phosphatic-sandstone 

Tuffaceous-sandstone 

Turbidites 

Calcareous-rocks 

Carbonate-rocks 

Calcarenite 

Marl 

Limestone 

Carbonaceous-limestone 

Phosphatic-limestone 

Cherty-limestone 

Siliceous-limestone 

67 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

68 

Rock-Types--Continued 

Sedilnentary~ontinued 

Calcareous-rocks~ontinued 

Carbonate-rocks--Continued 

Quartz-carbonate-rocks 

Dolomite 

Carbonaceous-dolomite 

Cherty-dolomite 

Calcareous-shale 

Calcareous-graywacke 

Calcareous-phyllite 

Calcareous-slate 

Marble 

Calc-silicates 

Other-sedimentary -rocks 

Conglomerate 

Phosphorite 

Chert 

Agglomerate 

Evaporites 

Gravel 

Anhydrite 

Gypsum 

Iron-formation 

Shell-rocks 

Jasper 

Metamorphic 

Regional-metamorphic 

Gneisses 

Schists 

Gneiss 

Biotite-gneiss 

Biotite-hornblende-gneiss 

Diorite-gneiss 

Gamet -gneiss 

Granite-gneiss 

Hornblende-gneiss 

Granodiorite-gneiss 

Graphite-gneiss 

Microcline-gneiss 

Oligoclase-gneiss 

Pyroxene-gneiss 

Quartz-biotite-gneiss 

Syenite-gneiss 

Alkalic-fenitized -gneiss 

Schist 

Amphibole-schist 

Biotite-schist 

Biotite-sillimanite-schist 

Calcite-biotite-schist 

Graphitic-schist 

Chlorite-schist 

Garnet-biotite-schist 

Hornblende-schist 

Mica-schist 

Staurolite-schist 

Talc-schist 

Tremolite-phlogopite-schist 

Quartz-mica-schist 

('I 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

Rock-Types--Continued 

Metamorphic-Continued 

Regional-metamorphic-Continued 

Amphibolites 

Amphibolite 

Epidote-amphibolite 

Meta-gabbro 

Serpentinite 

Metasedimentary-rocks 

Marble 

Fine-grained-metasedimentary-rocks 

Phyllites 

Argillite 

Slates 

Phyllite 

Calcarous-phyllite 

Sericitic-phyllite 

Slate 

Calcareous-slate 

Quartzose-slate 

Coarse-grained -metasedimentary-rocks 

Quartzite 

Metavolcanic-rocks 

Felsic-metavolcanic-rocks 

Mafic-metavolcanic-rocks 

Mafic-metatuff 

Contact-metamorphic-rocks 

Hornfels 

Quartzite 

Siliceous-dolomite 

Marble 

Ferrite 

Other-metamorphic-rocks 

Breccia 

Greenstone 

Mylonite 

Ophiolite 

Other rock-types 

Alwninous-silicate-rocks 

Apatite-magnetite-rocks 

Breccia 

Form-Structure 

Vein 

Fissure 

Fracture 

Veins 

Lode 

. Greisen 

Pegmatite 

Shear-zone 

Fissures 

Fissure-filling 

Fractures 

Veinlets 

Porphyry 

Stockwork 

Veinlets 

Stock 

Zoned-complex 

69 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

70 

Fonn-Structure-Continued 

Stratiform 

Zoned-complex 

Layered-complex 

Massive 

Bedded 

Banded 

Lenses 

Disseminated 

Pellets 

Nodules 

Oolites 

Pisolites 

Fine-grained 

Fossil-fragments 

Gash-filling 

Ribbon-veins 

Replacement 

Surficial 

Alteration 

Type 

Process 

Contact -metasomatic 

Skarn 

Massive-replacement 

Open-space-filling 

Breccia 

Gossan 

Laterite 

Placer 

Spilitic 

Zoned 

Potassic 

Phyllic 

Propylitic 

Argillic 

Pipe 

Collapse-breccia 

Breccia-filling 

Diatreme 

Sericitization 

Sericite 

Sericitization 

Sericite 

Kaolinization 

Kaolin 

Sodic-calcic 

(Zeolites) 

Supergene 

Leaching 

Sericitization 

Sericite 

Dolomitization 

Dolomite 

Albitization 

Albite 

Kaolinization 

Kaolin 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

Alteration-Continued 

Proces~ontinued 

Oxidation 

(Oxides) 

Jarosite 

Alunite 

Gossan 

Hematization 

Hematite 

Serpentinization 

Serpentine 

Silicification 

(Silicates) 

Tourmalinization 

Tourmaline 

Feldspar-destruction 

Chloritization 

Chlorite 

Pyritization 

Pyrite 

Fenitization 

Fenite 

Greisenization 

Greisen 

Carbonation 

(Carbonates) 

Amorphous-carbon 

Recrystallization 

Reduction 

Replacement 

Calc-silicates 

En do skarn 

Exoskarn 

Geochemical-Elements 

(all-elements-in-periodic-table) 

REE 

Minerals 

(Y LaCe FT Nd Pm Sm Eu Gd Tb Dy Ho Er Tm Yb Lu) 

PGE 

(Ru Rh Pd Os Ir Pt) 

NH3 

Hydrocarbons 

Native-elements 

Metals 

Gold 

Silver 

Copper 

Platinum 

Iron 

Mercury 

Amalgam 

Semimetals 

Arsenic 

Bismuth 

Nonmetals 

Sulfur 

Diamond 

Carbonado 

71 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

72 

Minerals-Continued 

Native-elements-Continued 

Nonmetals-Continued 

Diamond-Continued 

Ballas 

Sulfides 

Bart 

Graphite 

Iron-sulfides 

Pyrite 

Pyrrhotite 

Marcasite 

Arsenopyrite 

Chalcopyrite 

Stannite 

Bornite 

Cubanite 

Pentlandite 

Mackinawite 

Lead-sulfides 

Galena 

Zinc-sulfides 

Sphalerite 

Sulfides-other-than.Fe.Pb.Zn 

Silver-sulfides 

Argentite 

Copper-sulfides 

Chalcopyrite 

Stannite 

Bornite 

Carrollite 

Covellite 

Chalcocite 

Cubanite 

Digenite 

Nickel-sulfides 

Pentlandite 

Millerite 

Mackinawite 

Cobalt -sulfides 

Cobaltite 

Cinnabar 

Cooperite 

Laurite 

Molybdenite 

Greenockite 

Realgar 

Orpiment 

Stibnite 

Bismuthinite 

Gersdorffite 

Selenides-Tellurides-Arsenides-Antimonides 

Selenides 

Naumannite 

Tellurides 

Hessite 

Coloradoite 

Calaverite 

Sylvanite 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

Minerals-Continued 

Selenides-Tellurides-Arsenides-Antimonides-Continued 

Arsenides 

Pararammels bergi te 

Maucherite 

Skutterudite 

Sperry lite 

Loellingite 

Arsenopyrite 

Niccolite 

Antimonides 

Polarite 

Sulfosalts 

Oxides 

Jamesonite 

Silver-sulfosalts 

Pyrargyri te 

Proustite 

Copper-sulfosalts 

Tetrahedrite 

Tennantite 

Enargite 

Luzonite 

Boumonite 

Cuprite 

Zincite 

Cassiterite 

Spinel 

Chromite 

Gahnite 

Hydroxides 

Ferrichromite 

Brucite 

Manganite 

Valleriite 

Goethites 

Limonite 

Goethite 

Bauxite-minerals 

Gibbsite 

Boehmite 

Diaspore 

Columbite 

Chrysoberyl 

Mn-oxides 

Pyrolusite 

Todorokite 

Braunite 

Cryptomelane 

Coronadite 

Hausmannite 

Hollandite 

Psilomelane 

Iron-oxides 

Hematite 

Magnetite 

Ilmenite 

Leucoxene 

73 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

74 

Minerals-Continued 

Oxides-Continued 

Halides 

Titanium -oxides 

Rutile 

Anatase 

llmenite 

Leucoxene 

Uranium-oxides 

Uraninite 

Pitchblende 

Coffinite 

Carnotite 

Chlorides 

Fluorides 

Halite 

Sylvite 

Cerargyrite 

Atacamite 

Carnallite 

Cryolite 

Fluorite 

Parisite 

Bastnaesite 

Carbonates 

Hydrous 

Malachite 

Azurite 

Trona 

Anhydrous 

Calcite 

Dolomite 

Ankerite 

Siderite 

Smithsonite 

Aragonite 

Witherite 

Strontianite 

Cerussite 

Bastnaesite 

Breunnerite 

Mn-carbonates 

Rhodochrosite 

Manganocalcite 

Magnesite 

Parisite 

Nitrates-Borates-Phosphates-Arsenates 

Nitrates 

Borates 

Phosphates 

Apatite 

Fluorapatite 

Monazite 

Arsenates 

Beudantite 

Durangite 

Mimetite 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

Minerals-Continued 

Sulfates 

Anhydrous-sulfates 

Barite 

Celestite 

Anglesite 

Anhydrite 

Hydrous-sulfates 

Gypsum 

Chalcanthite 

Epsomite 

Antlerite 

Alunite 

Beudantite 

Tungstates 

Wolframite 

Huebnerite 

Scheelite 

Silicates 

Titano-silicates 

Sphene 

Ortho-silicates 

Phenacites 

Phenacite 

Willemite 

Olivines 

Datolite 

Sphene 

Garnets 

Forsterite 

Fayalite 

Gamet 

Andradite 

Grossularite 

Pyrope 

Spessartine 

Uvarovite 

Chondrodites 

Alleghanyite 

Aluminum -silicates 

Staurolite 

Topaz 

Andalusite 

Kyanite 

Sillimanite 

Zircon 

Allanite 

Di -silicates 

Hemimorphite 

Lawsonite 

Niocalite 

Epidotes 

Zoisite 

Clinzoisite 

Epidote 

Vesuvianite 

75 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

76 

Minerals-Continued 

Silicates-Continued 

Cyclosilicates 

Axinite 

Beryls 

Beryl 

Emerald 

Cordie rite 

Tourmaline 

Chain-silicates 

Pyroxenes 

Clino-pyroxenes 

Hedenbergite 

Augite 

Jadeite 

Aegirine 

Diopside 

Spodumene 

Ortho-pyroxenes 

Enstatite 

Hypersthene 

Pyroxenoids 

Wollastonite 

Pectolite 

Rhodonite 

Amphiboles 

Amphibole 

Anthophyllite 

Tremolites 

Sheet-silicates 

Tremolite 

Actinolite 

Cummingtonite 

Hornblende 

Riebeckites 

Glaucophane 

Riebeckite 

Apophyllite 

Clay-minerals 

Illite 

Attapulgite 

Bementite 

Neotocite 

Montmorillonites 

Kaolin 

Montmorillonite 

Beidellite 

Nontronite 

Hectorite 

Saponite 

Kaolinite 

Dickite 

Halloysite-7 A 

Halloysite-1 oA 

Allophane 

Serpentine 

Garnierite 

Pyrophy llite 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

Minerals-Continued 

Silicates-Continued 

Sheet-silicates-Continued 

Talc 

Asbestos 

Micas 

Chrysotile 

Mica 

Muscovite 

Sericite 

Magnesia -mica 

Phlogopite 

Biotite 

Glauconite 

Lepidolite 

Marg'arite 

Chlorites 

Prehnite 

Chrysocolla 

Framework -silicates 

Silicas 

Feldspars 

Silica 

Quartz 

Chalcedony 

Jasper 

Chert 

Opal 

Cristobalite 

Tridymite 

Feldspar 

Plagioclase-feldspars 

Plagioclase 

Albite 

Oligoclase 

Andesine 

Labradorite 

Bytownite 

Anorthite 

Barium-feldspar 

K-fcldspar 

Microcline 

Adularia 

Orthoclase 

Sanidine 

Anorthoclase 

Feldspathoids 

Leucite 

Nepheline 

Sodalite 

Lazurite 

Petalite 

Scapolites 

Zeolites 

Zeolite 

Analcime 

Natrolite 

Chabazite 

77 
Appendix C. Taxonomy used to define the attributes of numerical mineral deposit models-Continued 

78 

Minerals-Continued 

Silicates~ontinued 

Framework -silicates~ontinued 

Zeolite~ontinued 

Heulandite 

Stilbite 

Titanites-Niobates-Tantalates 

Titanites 

Perovskite 

Brannerite 

Niobates 

Pyrochlore 

Tantalates 

Alteration -products 

Carbonates 

Geophysics 

Silicates 

Zeolites 

Oxides 

Alunite 

Chlorite 

Greisen 

Calc-silicates 

Skarn 

Jaresite 

Amorphous-carbon 

Geophysical-anomalies 

Magnetic-anomaly 

Magnetic-high 

Magnetic-low 

Gravity-anomaly 

Gravity-high 

Gravity-low 

Radioactive-anomaly 

Endoskam 

Exoskam 

Electromagnetic-anomaly 

Induced-polarization-anomaly 
Appendix D. Worksheets for numerical mineral deposit models 

The model number for each numerical model refers to the model number of the corresponding descriptive model 

described in Cox and Singer (1986). The worksheets are designed so that the worksheet for each model can be reproduced and used to score a particular mineral occurrence, prospect, or deposit. Space is provided for entering the scores of 

individual attributes, partial scores of headings, and the total model score. The explanations of the pair of numbers that 

follows some of the attributes and of the rules for scoring attributes are described in the text. 

79 
Model1 

80 

Worksheet for Numerical Model of Stillwater Ni-Cu 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Ultramafic-plutonic (5-5) __ Gabbro (4 -2) __ Dunite (3 -1) __ Peridotite (3 -1) __ 

Pyroxenite (3 -1 ) __ Anorthosite(3 -1 ) __ 

TextureStructure: Stratiform __ Massive __ 

Alteration: 

Mineralogy: Pyrrhotite (2 -5) __ Chalcopyrite (2 -5) __ Pentlandite (2 -5) __ 

Cobalt-sulfides (2 -5) __ 

GeochemicalSignature: Cu (4 -5) __ Ni (4 -5) __ PGE (4 -5) __ Mg (2 -5) __ 

GeophysicalS ignature: 

AssociatedDeposits: Stillwater-Ni-Cu __ B ushveld-Cr __ Merensky-Reef-PGE __ 

Bushveld-Fe-Ti-U __ Placer-Au-PGE __ Placer-PGE-Au 

MaxScore: 1645 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Bush veld Cr 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Ultramafic-plutonic (5-5) __ Gabbro (4 -2) __ Dunite (3 -1) __ 

Peridotite (3 -!) __ Pyroxenite (3 -1) __ Anorthosite (3 -1) __ 

TextureStructure: Massive __ Disseminated __ Bedded __ 

Alteration: 

Mineralogy: Chromite (4 -5) __ Ilmenite (2 -4) __ Magnetite (2 -4) __ Pyrrhotite (2 -5) __ 

Pentlandite (4 -4) __ Chalcopyrite (2 -5) __ 

GeochemicalSignature: Cr (4 -5) __ PGE (4 -5) __ Mg (2 -5) __ 

GeophysicalS ignature: 

AssociatedDeposits: Bushveld-Cr __ Stillwater-Ni-Cu __ Merensky-Reef-PGE __ 

Bushveld-Fe-Ti-V __ Placer-PGE-Au __ Placer-Au-PGE __ 

MaxScore: 1705 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model2a 

81 
Model2b 

82 

Worksheet for N umcrical Model of Merensky Reef PGE 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Ultramafic-plutonic (5-5) __ Gabbro (4 -3) __ Dunite (3 -1) __ Peridotite (3 -1) __ 

Pyroxenite (3 -1) __ Anorthosite (3 -1) __ 

TextureStructure: Massive __ Disseminated __ 

Alteration: 

Mineralogy: Pyrrhotite (2 -5) __ Chalcopyrite (2 -5) __ Pentlandite (3 -5) __ Chromitc (4 -3) __ 

Graphite (2 -3) __ 

GeochemicalSignature: PGE (4 -5) __ Cu (2 -5) __ Ni (3 -5) __ Cr (3 -5) __ Ti (2 -4) __ 

Mg(2-5)_ 

GeophysicalS ignature: 

AssociatedDeposits: Merensky-Recf-PGE __ Stillwatcr-Ni-Cu __ Bushvcld-Cr __ 

Bushveld-Fe-Ti-V __ Placer-POE-Au __ Placer-Au-POE __ 

MaxScore: 1750 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructurc: __ Alteration: __ 

Mineralogy: __ GcochemicalS ignature: __ GeophysicalS ignature: __ 

AssociatedDeposits: __ 

Model Score: 
Worksheet for Numerical Model of Bush veld Fe-Ti-V 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Ultramafic-plutonic (5-5) __ Gabbro (4 -2) __ Anorthosite (4 -2) __ 

TextureStructure: Massive __ 

Alteration: 

Mineralogy: Magnetite (2 -5) __ Ilmenite (2 -5) __ Sulfides (2 -5) __ 

GeochemicalSignature: Fe (3 -5) __ Ti (3 -5) __ V (3 -5) __ 

GeophysicalSignature: 

AssociatedDeposits: Bushveld-Fe-Ti-V __ Bushveld-Cr __ Stillwater-Ni-Cu __ 

Merensky-Reef-PGE __ Placer-POE-Au __ Placer-Au-POE __ 

MaxScore: 1420 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model3 

83 
Model Sa 

84 

Worksheet for Numerical Model of Duluth Cu-Ni-PGE 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Ultramafic-plutonic (5 -5) __ Peridotite (4 -2) __ Pyroxenite (4 -2) __ 

Anorthosite (3 -2) __ Evaporites (2 -1) __ 

TextureStructure: Massive __ Disseminated __ 

Alteration: 

Mineralogy: Pyrrhotite (2 -3) __ Pentlandite (3 -5) __ Chalcopyrite (2 -5) __ 

Cubanite (3 -4) __ Graphite (2 -3) __ 

GeochemicalSignature: Ni (4 -5) __ Cu (4 -5) __ PGE (2 -5) __ Co (2 -4) __ 

Ti (2-4)_ 

GeophysicalS ignature: 

AssociatedDeposits: Duluth-Cu-Ni-PGE __ 

Max Score: 910 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model ofNoril'sk Cu-Ni-PGE 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Paleozoic __ 

RockTypes: Basalt (5-5) __ Ultramafic-plutonic (5-5) __ Gabbro (4 -2) __ 

Volcanic-breccia (3 -I) __ Evaporites (2 -1) __ 

TextureStructure: Lenses __ Massive __ Disseminated __ 

Alteration: 

Mineralogy: Pyrrhotite (2 -3) __ Pentlandite (3 -5) __ Chalcopyrite (2 -5) __ 

Cubanite (3 -4) __ Millerite (2 -3) __ Valleriite (2 -3) __ Pyrite (2 -4) __ _ 

Bornite (2 -3) __ Gersdorffite (3 -2) __ Sperrylite (3 -2) __ Polarite (2 -2) __ 

Arsenides (2 -3) __ Antimonides (2 -3) __ 

GeochemicalSignature: Ni (4 -5) __ Cu (4 -5) __ Co (2 -5) __ Pt (2 -5) __ 

Pd(2-5)_ 

GeophysicalS ignature: 

AssociatedDeposits: Noril'sk-Cu-Ni-PGE __ 

MaxScore: 1195 

Partial Scores 

Age Range: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model5b 

85 
Model6a 

86 

Worksheet for Numerical Model ofKomatiitic Ni-Cu 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Cretaceous __ Tertiary __ 

RockTypes: Ultramafic-plutonic (5 -5) __ Komatiite (5 -5) __ 

TextureStructure: Lenses __ Massive __ Disseminated __ 

Alteration: 

Mineralogy: Pyrite (2 -4) __ Pyrrhotite (2 -5) __ Chalcopyrite (2 -5) __ Pentlandite (4 -5) __ 

GeochemicalSignature: Mg (2 -5) __ Ni (4 -5) __ Cu (4 -5) __ PGE (2 -4)_ Pd (2 -4) __ 

GeophysicalSignature: 

AssociatedDeposits: Komatiitic-Ni-Cu __ 

MaxScore: 760 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Dunitic Ni-Cu 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ 

RockTypes: Ultramafic-plutonic (5-5) __ Dunite (4 -2) __ Peridotite (4 -2) __ 

TextureStructure: Massive __ Lenses __ 

Alteration: Serpentinization (5 -2) __ 

Mineralogy: Pyrrhotite (2 -5) __ Pentlandite (3 -5) __ Magnetite (2 -5) __ Pyrite (2 -4) __ 

Chalcopyrite (2 -5) __ Chromite (3 -5) __ 

GeochemicalSignature: Ni (4 -5) __ Cu (4 -4) __ PGE (2 -5) __ Cr (2 -5) __ Co (2 -5) __ 

Mg(2-5)_ 

GeophysicalS ignature: 

AssociatedDeposits: Dunitic-Ni-Cu __ Komatiitic-Ni __ S ynorogenic-synvolcanic-Ni __ 

Talc-carbonate-Ni-Au __ Layered-sedimentary-Ni __ 

MaxScore: 1895 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model6b 

87 
Model7a 

88 

Worksheet for Numerical Model of Synorogenic-synvolcanic Ni-Cu 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Mafic-plutonic (5-5) __ Gabbro (4 -2) __ Ultramafic-plutonic (4 -4) __ 

Anorthosite (3 -1 ) __ 

TextureStructure: Disseminated __ 

Alteration: 

Mineralogy: Pyrrhotite (2 -5) __ Pentlandite (4 -5) __ Chalcopyrite (2 -5) __ Pyrite (2 -3) __ 

Magnetite (2 -4) __ Graphite (2 -3) __ 

GeochemicalSignature: Ni (4 -5) __ Cu (4 -5) __ Co (2 -5) __ PGE (3 -5) __ 

GeophysicalS ignature: 

AssociatedDeposits: Synorogenic-synvolcanic-Ni -Cu __ Komatiitic-Ni -Cu __ Dunitic-Ni-Cu __ 

Talc-carbonate-Ni-Au __ 

MaxScore: 1345 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 
Worksheet for Numerical Model of Anorthosite Ti 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ 

RockTypes: Anorthosite (5-5) __ Ferrodiorite (4 -2) __ Gabbro (3 -1) __ Charnockite (2 -1) __ 

Jutunite (2 -1) __ 

TextureStructure: Massive-replacement __ Contact -metasomatic __ 

Alteration: 

Mineralogy: Ilmenite (3 -5) __ Rutile (3 -2) __ Apatite (2 -3) __ 

GeochemicalSignature: Ti (4 -5) __ P (2 -5) __ Zr (2 -4) __ 

GeophysicalSignature: Magnetic-high __ 

AssociatedDeposits: Anorthosite-Ti __ 

MaxScore: 755 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model7b 

89 
Model Ba and Bb 

90 

Worksheet for Numerical Model ofPodiform chromite 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Phanerozoic __ 

RockTypes: Ultramafic-plutonic (5-5) __ Dunite (4 -2) __ Peridotite (4 -2) __ Ophiolite (4 -2) __ 

TextureStructure: Massive __ Disseminated __ 

Alteration: Serpentinization (5 -2) __ 

Mineralogy: Chromite (4 -5) __ Ferrichromite (4 -5) __ Magnetite (2 -3) __ Laurite (3 -2) __ 

GeochemicalSignature: Cr (5-5) __ 

GeophysicalS ignature: 

AssociatedDeposits: Podiform-chromite __ Limassol-Forest -Co-Ni __ 

MaxScore: 1325 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model ofLimassol Forest Co-Ni 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Paleozoic __ Mesozoic __ 

RockTypes: Serpentinite (5-5) __ Ultramafic-plutonic (5-4) __ 

TextureStructure: Veins __ 

Alteration: Serpentinization (5 -2) __ Silicification __ Carbonation __ 

Mineralogy: Pyrrhotite (2 -5) __ Pyrite (2 -4) __ Pentlandite (3 -3) __ Chalcopyrite (2 -4) __ 

Valleriite (3 -4) __ Loellingite (3 -2) __ Niccolite (3 -2) __ Maucherite (2 -2) __ 

Skutterudite (2 -2) __ Gersdorffite (2 -2) __ Cobaltite (2 -4) __ Magnetite (2 -4) __ 

Chromite (3 -3) __ Mackinawite (2 -2) __ Pararammelsbergite (2 -2) __ 

GeochemicalSignature: As (2 -5) __ Co (4 -5) __ Ni (4 -5) __ 

GeophysicalSignature: 

AssociatedDeposits: Limassol-Forest -Co-Ni __ Podiform -chromite __ 

Ni -laterite __ Co-Ni -Cu-ophiolite-sulfide __ 

MaxScore: 2125 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model8c 

91 
Model8d 

92 

Worksheet for Numerical Model of Serpentine-hosted asbestos 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Serpentinite (5 -5) __ Ultramafic-plutonic (5 -5) __ 

TextureStructure: Gash-filling __ Ribbon-veins __ 

Alteration: Silicification (5 -2) __ Carbonation (5 -2) __ Serpentinization (5 -5) __ 

Mineralogy: Chrysotile (3 -5) __ Asbestos (5-5) __ Magnetite (2 -4) __ 

Brucite (2 -3) __ Talc (3 -3) __ Tremolite (2 -2) __ Actinolite (2 -2) __ 

GeochemicalSignature: Mg (2 -5) __ 

GeophysicalSignature: Magnetic-high __ 

AssociatedDeposits: Serpentine-hosted -asbestos __ Podiform -chromite __ 

MaxScore: 2090 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalS ignature: __ GeophysicalS ignature: __ 

AssociatedDeposits: __ 

Model Score: 
Worksheet for Numerical Model of Alaskan PGE 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Paleozoic __ Mesozoic __ 

RockTypes: Ultramafic-plutonic (5 -5) __ Zoned-ultramafic (5 -5) __ Dunite (3 -1 ) __ 

Peridotite (3 -1 ) __ Pyroxenite (3 -1 ) __ Gabbro (2 -1 ) __ Felsic-plutonic (2 -1 ) __ 

Intermediate-plutonic (2 -1 ) __ 

TextureStructure: Zoned-complex __ 

Alteration: Serpentinization (5 -2) __ 

Mineralogy: Chromite (4 -5) __ Pentlandite (2 -2) __ Pyrrhotite (2 -3) __ Gold (2 -3) __ 

Arsenides (2 -4) __ Magnetite (2 -4) __ Cooperite (2 -3) __ Bornite (2 -3) __ 

Chalcopyrite (2 -3) __ 

GeochemicalSignature: Cr (4 -5) __ PGE (4 -5)_ Ti (2 -4)_ V (2 -4) __ Cu (2 -5)_ 

Ni (2 -5)_ S (2 -5)_ As (2 -4)_ 

GeophysicalS ignature: 

AssociatedDeposits: Alaskan-PGE __ Placer-PGE-Au __ Placer-Au-PGE __ 

MaxScore: 1925 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model9 

93 
Model10 

94 

Worksheet for Numerical Model of Carbonatite deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

Age Range: Precambrian __ Phanerowic __ 

RockTypes: Apatite-magnetite-rocks (4 -2) __ Sovite (3 -1) __ Ankerite-carbonatite (3 -1) __ 

Fenite (2 -1 ) __ Ijolite (2 -1 ) __ Dunite (2 -1 ) __ Picrite-porphyrites (2 -1 ) __ 

Alkalic-fenitized-gneiss (2 -1) __ 

TextureStructure: Zoned-complex __ 

Alteration: Fenitization (5 -2) __ Chloritization __ 

Mineralogy: Apatite (3 -4 ) __ Magnetite (2 -4 ) __ Pyrochlore (2 -4 ) __ Columbite (2 -4 ) __ 

Perovskite (2 -4) __ Niocalite (2 -4) __ Barite (2 -4) __ Strontianite (2 -3) __ Siderite (2 -3) __ 

Rhodochrosite (2 -2) __ Ankerite (2 -3) __ Bastnaesite (2 -4) __ Chlorite (2 -2) __ 

Parisite (2 -2) __ Monazite (2 -3) __ Breunnerite (2 -3) __ Calcite (2 -4) __ Dolomite (2 -4) __ 

Fluorite (2 -4) __ Pyrrhotite (2 -4) __ Ilmenite (2 -2) __ Molybdenite (2 -4) __ 

Chalcopyrite (2 -5) __ Pyrite (2 -4) __ Sphalerite (2 -4) __ 

GeochemicalSignature: REE (4 -5) __ Th (2 -5) __ U (2 -5)_ Ti (2 -4) __ Zn (2 -4) __ 

Nb (2 -4)_ Y (3 -5)_ Ce (3 -5)_ Mo (2 -4)_ Cu (2 -3)_ V (2 -5)_P (2 -5)_ 

Mn (2 -3)_ S (2 -5)_La (3 -5)_ Sm (3 -5)_Pb (2 -3)_Zr (2 -4)_ Ba (2 -4)_ 

Eu(3 -5)_ 

GeophysicalSignature: Radioactive-anomaly __ Magnetic-high __ 

AssociatedDeposits: Carbonatite __ 

MaxScore:2570 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Diamond pipes 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Kimberlite (5-4) __ Olivine-lamproite (3 -1) __ Leucite-lamproite (3 -1) __ 

TextureStructure: Diatreme __ Pipe __ Breccia __ 

Alteration: Serpentinization (5 -2) __ 

Mineralogy: Diamond (5 -5) __ Bort (5 -5) __ Carbonado (5 -5) __ 

GeochemicalSignature: Cr (2 -5) __ Ti (2 -5) __ Mn (2 -4) __ Ni (2 -5) __ 

Co (2 -4)_ PGE (3 -4)_ Ba (2 -3)_ 

GeophysicalSignature: 

AssociatedDeposits: Diamond-pipes __ Diamond-placers __ 

MaxScore: 1415 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model12 

95 
Model14a 

96 

Worksheet for Numerical Model of W skarn deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Calcareous-Rocks (5 -5) __ Felsic-plutonic (5 -5) __ 

TextureStructure: Skarn __ 

Alteration: Diopside __ Hedenbergite __ Andradite __ Spessartine __ 

Mineralogy: Scheelite (4 -5) __ Molybdenite (2 -2) __ Pyrrhotite (2 -2) __ Sphalerite (2 -2) __ 

Chalcopyrite (2 -2) __ Bornite (2 -2) __ Arsenopyrite (2 -2) __ Pyrite (2 -4) __ 

Magnetite (2 -3) __ 

GeochemicalSignature: W (4 -5) __ Mo (2 -5) __ Zn (2 -4) __ Cu (2 -4) __ Sn (2 -5) __ 

Bi (2 -4)_ Be (2 -5)_ As (2 -4)_ 

GeophysicalS ignature: 

AssociatedDeposits: W -skarn __ Zn-skarn __ Sn-W -skarn __ 

MaxScore: 1670 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Model14b 

Worksheet for Numerical Model of Sn skarn deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Granite (5-5) __ Biotite-leucogranite (4 -2) __ Muscovite-leucogranite (4 -2) __ 

Felsic-dikes (2 -1) __ Calcareous-Rocks (5 -5) __ 

TextureStructure: Skarn __ Breccia __ 

Alteration: Greisenization (5-2) __ 

Mineralogy: Cassiterite (4 -5) __ Scheelite (4 -4) __ Sphalerite (2 -4) __ Chalcopyrite (2 -4) __ 

Pyrrhotite (2 -4) __ Magnetite (2 -3) __ Pyrite (2 -3) __ Arsenopyrite (2 -3) __ Fluorite (4 -4) __ 

GeochemicalSignature: Sn (4 -5) __ W (4 -5) __ F (4 -4) __ Be (2 -4) __ Zn (2 -4) __ 

Pb (2 -3)_ Cu (2 -4)_ Ag (2 -3)_ Li (2 -4)_ Rb (2 -5)_ Cs (2 -4)_ Re (2 -4)_ 

B(2-5)_ 

GeophysicalS ignature: 

AssociatedDeposits: Sn-skarn __ W -skarn __ Sn-greisen __ Sn-vcins __ Sn-rcplacement __ 

MaxScore: 2390 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GcophysicalS ignature: __ 

AssociatedDeposits: __ 

Model Score: 

97 
Model14c 

98 

Worksheet for Numerical Model of Replacement Sn 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Calcareous-Rocks (5-5) __ Felsic-plutonic (5-5) __ 

TextureS tructure: Massive-replacement __ 

Alteration: Greisenization (5-2) __ 

Mineralogy: Pyrrhotite (2 -4) __ Arsenopyrite (2 -4) __ Cassiterite (4 -5) __ Chalcopyrite (2 -4) __ 

Ilmenite (2 -3) __ Fluorite (4 -5) __ 

GeochemicalSignature: Sn (4 -5) __ As (2 -5)_ Cu (2 -5)_ B (2 -4) __ W (4 -4) __ F (4 -5) __ 

Li (2 -5)_ Pb (2 -4)_ Zn (2 -4)_ Rb (2 -5)_ 

GeophysicalS ignature: 

AssociatedDeposits:Replacement-Sn __ Sn-greisen __ Quartz-tourmaline-cassiterite-veins __ 

W -skarn __ Sn-skarn __ 

MaxScore: 2030 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model ofW veins 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Felsic-plutonic (5-5) __ Sandstone (3 -1) __ Shale (3 -1) __ 

TextureStructure: Veins __ 

Alteration: Albitization __ Sericitization __ Chloritization __ 

Mineralogy: Wolframite (4 -5) __ Molybdenite (2 -5) __ Bismuthinite (4 -4) __ Pyrite (2 -4) __ 

Pyrrhotite (2 -3) __ Arsenopyrite (2 -5) __ Bornite (2 -3) __ Chalcopyrite (2 -5) __ 

Scheelite (4 -4) __ Cassiterite (4 -5) __ Beryl (2 -3) __ Fluorite (4 -4) __ 

GeochemicalSignature: W (4 -5) __ Mo (2 -5)_ Sn (4 -5)_ Bi (2 -5)_ As (2 -3) __ 

Cu (2 -3)_Pb (2 -3)_Zn (2 -3)_ Be (4 -3)_F (4 -4)_ 

GeophysicalSignature: 

AssociatedDeposits: W -veins __ Sn-veins __ 

MaxScore: 1795 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model15a 

99 
Model15b 

100 

Worksheet for Numerical Model of Sn veins 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Felsic-plutonic (5-5) __ Granite (5-5) __ Biotite-leucogranite (3 -2)__ 

Muscovite-leucogranite (3 -2) __ Pelitic-rocks (2 -1) __ 

TextureStructure: Veinlets __ Open-space-filling __ 

Alteration: Sericitization __ Tourmalinization __ Silicification __ Chloritization __ 

Hematization __ 

Mineralogy: Cassiterite (4 -5) __ Wolframite (3 -4) __ Arsenopyrite (2 -4) __ Molybdenite (2 -4) __ 

Hematite (2 -4) __ Scheelite (3 -3) __ Beryl (2 -3) __ Galena (2 -3) __ Chalcopyrite (2 -4) __ 

Sphalerite (2 -3) __ Stannite (3 -4) __ Bismuthinite (3 -3) __ 

GeochemicalSignature: Sn (4 -5) __ As (3 -4) __ W (3 -5) __ B (3 -4) __ Li (2 -4) __ 

Rb (2 -4)_ Cs (2 -4)_Be (2 -4)_REE (2 -4)_U (2 -4)_Th (2 -4)_ Nb (2 -4)_ 

Bi (2 -3)_ F (3 -5)_ 

GeophysicalS ignature: 

AssociatedDeposits: Sn-veins __ Sn-greisen __ Sn-skarn __ Sn-replacement __ 

MaxScore: 2430 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 
Model15c 

Worksheet for Numerical Model of Sn greisen deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Felsic-plutonic (5-5) __ Granite (5-5) __ Leucogranite (4 -4) __ 

Muscovite-leucogranite (3 -2) __ Biotite-leucogranite (3 -2) __ 

TextureStructure: Greisen __ Veinlets __ Stockwork __ 

Alteration: Greisenization (5 -2) __ Albitization (5 -2) __ Tourmalinization (3 -2) __ 

Mineralogy: Cassiterite (4 -5) __ Molybdenite (4 -5) __ Arsenopyrite (3 -5) __ Topaz (4 -2) __ 

Tourmaline (4 -2) __ Beryl (2 -4) __ Wolframite (2 -3) __ Bismuthinite (2 -2) __ 

Fluorite (4 -3) __ Calcite (1 -3) __ Pyrite (2 -4) __ 

GeochemicalSignature: Sn (4 -5) __ F (5 -5) __ B (5 -4) __ Mo (2 -5) __ Rb (2 -4) __ 

Cs (2 -4)_ Be (2 -3)_ REE (2 -4)_ U (2 -4)_ Th (2 -4)_ Nb (2 -4)_ Ta (2 -4)_ 

Li (2 -4)_W (2 -3)_As (2 -4)_ Bi (2 -3)_ 

GeophysicalSignature: 

AssociatedDeposits: Sn-greisen __ So-veins __ So-replacement __ 

MaxScore: 2930 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

101 
Model16 

102 

Worksheet for Numerical Model of Climax Mo deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Tertiary __ 

RockTypes: Felsic-plutonic (5-5) __ Granite ( 4 -5) __ Rhyolite (4 -3) __ 

TextureStructure: Stockwork __ Veinlets __ 

Alteration: Silicification (5 -2) __ Potassic (5 -2) __ 

Mineralogy: Molybdenite (4 -5) __ Fluorite (4 -5) __ K-fcldspar (2 -5) __ Pyrite (2 -4) __ 

Wolframite (2 -3) __ Cassiterite (4 -3) __ Topaz (4 -3) __ 

GeochemicalSignature: Mo (4 -5) __ Sn (4 -3) __ W (4 -5) __ Rb (3 -5) __ Pb (2 -4) __ 

Zn (2 -3)_F (3 -5)_Th (2 -3)_ K (2 -2)_Cs (2 -4)_Li (2 -4)_ Nb (2 -3)_ 

Ta (2 -3)_ Mn (2 -4)_ Re (2 -5)_ 

GeophysicalS ignature: 

AssociatedDeposits: Climax-Mo __ Ag -base-metal-veins __ Fluorspar __ 

MaxScore: 2445 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalS ignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Porphyry Cu 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

Age Range: Precambrian __ Phanerozoic __ 

Rock Types: Felsic-plutonic (5 -5) __ Tonalite ( 4 -1 ) __ Monzogranite ( 4 -1 ) __ Syenite ( 4 -1 ) __ 

TextureStructure: Stockwork __ Veinlets __ 

Alteration: Sodic-calcic __ Potassic (5 -2) __ Phyllic (5 -2) __ Argillic (5 -2) __ 

Propylitic (5 -2) __ 

Mineralogy: Chalcopyrite (3 -5) __ Pyrite (2 -5) __ Molybdenite (3 -4) __ Magnetite (2 -3) __ 

Bornite (3 -2)_Gold (3 -4)_ 

GeochemicalSignature: Cu (4 -5) __ Mo (3 -5)_ Au (2 -3) __ Ag (2 -4)_ W (2 -3) __ 

B (2 -3)_Pb (2 -4)_Zn (2 -4)_ As (2 -3)_ Sb (2 -3)_ Se (2 -3)_ Te (2 -4)_ 

Mn (2 -4)_ Rb (2 -3)_ Bi (2 -2)_ Sn (2 -3)_ K (1 -2)_ Fe (1 -2)_ 

GeophysicalSignature: 

AssociatedDeposits: Porphyry-Cu __ Base-metal-skam __ Epithermal-veins __ 

Polymetallic-replacement __ Volcanic-hosted-massive-replacement __ 

MaxScore: 3600 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model17 

103 
Model18a 

104 

Worksheet for Numerical Model of Porphyry Cu, skarn-related deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Felsic-plutonic (5 -3) __ Calcareous-Rocks (5 -5) __ 

TextureStructure: Skarn __ Veinlets __ 

Alteration: Potassic (5 -2) __ Marble __ Phyllic (5 -2) __ 

Mineralogy: Chalcopyrite (3 -5) __ Pyrite (2 -4) __ Magnetite (3 -3) __ Sphalerite (2 -3) __ 

Tennantite (3 -3) __ Scheelite (2 -2) __ 

GeochemicalSignature: Cu (3 -5) __ Mo (3 -5) __ Pb (2 -3) __ Zn (2 -3) __ Au (2 -4) __ 

Ag (2 -5)_ W (2 -2)_ Bi (2 -2)_ Sn (2 -3)_ As (2 -3)_ Sb (2 -3)_ Se (1 -3)_ 

GeophysicalSignature: 

AssociatedDeposits: Porphyry-Cu-skarn-related __ Cu-skarn __ Replacement-Pb-Zn-Ag __ 

MaxScore: 2200 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Cu skarn deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Felsic-plutonic (4 -2) __ Calcareous-Rocks (5-5) __ Hornfels (2 -1) __ 

TextureStructure: Skarn __ 

Alteration: Calc-silicates __ 

Mineralogy: Chalcopyrite (4 -5) __ Bornite (4 -5) __ Pyrite (2 -5) __ Magnetite (2 -4) __ 

Hematite (2 -3) __ Pyrrhotite (2 -3) __ 

GeochemicalSignature: Cu (3 -5) __ Au (2 -4 ) __ Ag (2 -5) __ Pb (2 -4 ) __ Zn (2 -4 ) __ 

B (2 -2)_ Co (2 -2)_ Mo (2 -4)_ W (2 -2)_ As (1 -2)_ Sb (1 -2)_ 

Bi (1 -2)_ S (2 -3)_ 

GeophysicalSignature: Magnetic-high __ 

AssociatedDeposits: Cu-skarn __ Porphyry-Cu __ Zn-skarn __ Polymetallic-replacement __ 

Fe-skarn __ 

MaxScore: 1740 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model18b 

105 
Model18c 

106 

Worksheet for Numerical Model of Zn-Pb skarn deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Felsic-plutonic (4 -3) __ Calcareous-Rocks (5-5) __ 

TextureStructure: Skarn __ 

Alteration: Calc-silicates __ 

Mineralogy: Sphalerite (3 -5) __ Galena (3 -5) __ Pyrrhotite (2 -4) __ Pyrite (2 -4) __ 

Magnetite (2 -3) __ Chalcopyrite (3 -4) __ Bornite (3 -3) __ Arsenopyrite (2 -3) __ 

Scheelite (2 -3) __ Bismuthinite (2 -3) __ Stannite (2 -2) __ Fluorite (2 -5) __ Gold (2 -2) __ 

Silver (2 -2) __ 

GeochemicalSignature: Zn (3 -5) __ Pb (3 -5) __ Mn (2 -5) __ Cu (2 -5) __ Au (2 -4) __ 

Ag (2 -5)_ As (2 -4)_ W (2 -3)_ Sn (2 -3)_ F (2 -3)_ Be (1 -2)_ Co (2 -3)_ 

s (1-3)_ 

GeophysicalS ignature: 

AssociatedDeposits: Zn-Pb-skarn __ Cu-skarn __ 

MaxScore: 1505 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Fe skarn deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Calcareous-Rocks (5 -5) __ Felsic-plutonic (5-3) __ Diabase (2 -1) __ 

TextureStructure: Skarn __ 

Alteration: Calc-silicates __ 

Mineralogy: Magnetite (4 -5) __ Chalcopyrite (2 -4) __ Pyrite (2 -4) __ Pyrrhotite (2 -4) __ 

GeochemicalSignature: Fe (4 -5) __ Cu (2 -4) __ Co (2 -2) __ Au (2 -5) __ Be (2 -2) __ 

B (2 -2)_ Zn (2 -2)_ Sn (1 -1)_ 

GeophysicalSignature: Magnetic-high __ 

AssociatedDeposits: Fe-skarn __ 

MaxScore: 960 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalS ignature: __ GeophysicalSignaturc: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model18d 

107 
Model18e 

108 

Worksheet for Numerical Model of Carbonate-hosted asbestos 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

Age Range: Precambrian __ Phanerozoic __ 

RockTypes: Serpentinite (5-5) __ Diabase (2 -2) __ Siliceous-limestone (2 -1) __ 

Cherty-dolomite (2 -1) __ 

TextureStructure: Gash-filling __ Ribbon-veins __ 

Alteration: Calc-silicates __ 

Mineralogy: Chrysotile (4 -5) __ Asbestos (4 -5) __ Serpentine (3 -5) __ Magnetite (2 -5) __ 

Calcite (2 -5) __ 

GeochemicalSignature: Mg (3 -5) __ 

GeophysicalS ignature: 

AssociatedDeposits: Carbonate-hosted-asbestos __ Contact -metamorphic-magnetite __ Talc __ 

MaxScore: 1085 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Model19a 

Worksheet for Numerical Model of Polymetallic replacement deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Calcareous-Rocks (5 -5) __ Shale (3 -2) __ 

TextureStructure: Replacement __ Massive __ 

Alteration: Dolomitization __ Silicification __ Chloritization __ Pyritization __ 

Mineralogy: Enargite (2 -3) __ Sphalerite (2 -5) __ Argentite (2 -3) __ Tetrahedrite (2 -4) __ 

Digenite (2 -2) __ Chalcopyrite (2 -4 ) __ Galena (2 -4 ) __ Proustite (2 -4 ) __ 

Pyargyrite (2 -4) __ Pyrite (2 -5) __ Marcasite (2 -4) __ Barite (2 -4) __ 

GeochemicalSignature: Cu (2 -5) __ Pb (2 -5) __ Ag (2 -4) __ Zn (2 -5) __ Mn (2 -4) __ 

Au (2 -4)_ As (2 -3)_ Sb (2 -3)_ Bi (2 -3)_ Ba (2 -3)_ Ge (1 -2)_ Te (2 -3)_ 

s (2-5)_ 

GeophysicalSignature: 

AssociatedDeposits: Polymetallic-replacement __ Zn-Pb-skarn __ Porphyry-Cu __ 

MaxScore: 1805 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

109 
Model19b 

110 

Worksheet for Numerical Model of Replacement Mn 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Calcareous-Rocks (5 -5) __ Felsic-plutonic (5 -5) __ 

TextureStructure: Veins __ Open-space-filling __ 

Alteration: 

Mineralogy: Rhodochrosite (4 -5) __ Rhodonite (4 -3) __ Calcite (2 -4) __ Barite (2 -3) __ 

Fluorite (2 -3) __ Pyrite (2 -4) __ Chalcopyrite (2 -3) __ Galena (2 -2) __ Sphalerite (2 -3) __ 

GeochemicalSignature: Mn (4 -5) __ Cu (2 -4) __ Ag (2 -4) __ Au (2 -4) __ Pb (2 -4) __ 

Zn(2-4)_ 

GeophysicalS ignature: 

AssociatedDeposits: Replacement-Mn __ Polymetallic-veins __ Polymetallic-replacement __ 

Cu-skam __ Zn-skam __ Porphyry-Cu __ 

MaxScore: 1690 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
~f) 

Worksheet for Numerical Model of Porphyry Sn 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerowic __ 

RockTypes: Felsic-plutonic (5 -5) __ Felsic-volcanic-rocks (5-5) __ 

Calc-alkaline-pyroclastics (3 -1 ) __ 

TextureStructure: Disseminated __ Veinlets __ 

Alteration: Tourmalinization __ Sericitization __ Propylitic __ Argillic __ 

Mineralogy: Cassiterite (4 -5) __ Pyrite (2 -5) __ Pyrrhotite (2 -3) __ Stannite (4 -4) __ 

Chalcopyrite (2 -4) __ Sphalerite (2 -4) __ Arsenopyrite (2 -3) __ 

GeochemicalSignature: Sn (4 -5) __ B (2 -4) __ Ag (2 -4) __ Pb (2 -4) __ Zn (2 -4) __ 

As (2 -4)_ Sb (2 -4)_Cu (2 -4)_Ba(2 -4)_F (1 -2)_ 

GeophysicalSignature: 

AssociatedDeposits: Porphyry-Sn __ Sn-vein __ Sn-polymetallic __ 

MaxScore: 1730 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model20a 

111 
Model20b 

112 

Worksheet for Numerical Model of So-polymetallic veins 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Rhyolite (5 -5) __ Tuff-breccia (3 -2) __ Basalt (2 -1) __ Chert (2 -1) __ 

Slate (2 -1)_ 

TextureStructure: Veins __ 

Alteration: 

Mineralogy: Cassiterite (4 -5) __ Chalcopyrite (3 -5) __ Sphalerite (3 -5) __ Pyrrhotite (2 -5) __ 

Pyrite (2 -5) __ Galena (2 -4) __ Scheelite (3 -3) __ Wolframite (2 -4) __ 

Arsenopyrite (2 -4) __ Bismuthinite (2 -4) __ Argentite (2 -3) __ Gold (2 -4) __ 

Magnetite (2 -3) __ Molybdenite (2 -3) __ 

GeochemicalSignature: Sn (4 -5) __ Zn (2 -5) __ Pb (2 -5) __ W (3 -4) __ Ag (2 -5) __ 

Bi(3 -3)_As (2 -4)_Sb (2 -4)_B (2 -4)_F (1-2)_ 

GeophysicalS ignature: 

AssociatedDeposits: Sn-polymetallic-veins __ Polymetallic-replacement __ Epithermal-Ag-veins __ 

Porphyry-So __ 

MaxScore: 1750 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalS ignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 
Worksheet for Numerical Model of Porphyry Cu-Au 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Cretaceous __ Cenozoic __ 

RockTypes: Felsic-plutonic (5 -5) __ Felsic-volcanic-rocks (4 -4) __ Mafic-volcanic-rocks (4 -3) __ 

Shoshonite (3 -1 ) __ 

TextureStructure: Stockwork __ Veinlets __ 

Alteration: Chloritization __ Propylitic __ 

Mineralogy: Chalcopyrite (4 -5) __ Bornite (4 -4) __ Gold (4 -5) __ 

GeochemicalSignature: Cu (4 -5) __ Au (4 -5) __ Ag (2 -5) __ Mo (2 -4) __ Pb (2 -4) __ 

Zn (2 -4)_ Mn (2 -4)_ K (1 -2)_ 

GeophysicalSignature: 

AssociatedDeposits: Porphyry-Cu-Au __ Porphyry-Cu-Mo __ Placer-Au __ 

MaxScore: 1455 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model20c 

113 
Model21a 

114 

Worksheet for Numerical ~odel of Porphyry Cu-Mo 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Felsic-plutonic (5 -5) __ Tonalite (3 -2) __ Monzogranite (3 -2) __ 

TextureStructure: Stockwork __ Veinlets __ 

Alteration: Chloritization (5 -2) __ Potassic (5 -2) __ Propylitic (5 -2) __ Phyllic (5 -2) __ 

Mineralogy: Chalcopyrite (4 -5) __ Pyrite (2 -5) __ Molybdenite (4 -5) __ 

GeochemicalSignature: Cu (5-5) __ Mo (5-5) __ Ag (2 -5) __ W (2 -4)_Pb (2 -4) __ 

Zn (2 -4)_ Au (2 -5)_ As (2 -5)_ Sb (2 -4)_ Te (2 -4)_ Mn (2 -4)_ Rb (2 -3)_ 

K (l-2)_Re (2 -4)_ 

GeophysicalSignature: Magnetic-low __ 

AssociatedDeposits: Porphyry-Cu-Mo __ Cu-skarn __ Zn-skam __ Fe-skarn __ Placer-Au __ 

Polymetallic-replacement __ Volcanic-hosted-massive-replacement __ 

MaxScore: 3585 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Porphyry Mo, low-F 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Mesozoic __ Tertiary __ 

RockTypes: Felsic-plutonic (5 -5) __ Felsic-hypabyssal (5 -2) __ Tonalite (3 -1) __ 

Granodiorite (3 -1) __ Monzogranite (3 -1) __ Quartz-monzonite (3 -1) __ 

TextureStructure: Stockwork __ Veinlets __ 

Alteration: Potassic (5 -2) __ Propylitic (5 -2) __ Phyllic (5 -2) __ Argillic (5 -2) __ 

Silicification (5-2) __ 

Mineralogy: Molybdenite (4 -5) __ Pyrite (2 -5) __ Scheelite (2 -4) __ Chalcopyrite (3 -5) __ 

Tetrahedrite (2 -4 ) __ 

GeochemicalSignature: Mo (2 -5) __ Cu (2 -4) __ W (2 -4) __ Re (2 -2) __ Zn (2 -2) __ 

Pb (2 -2)_ Au (2 -2)_ Ag (2 -2)_ K (1 -2)_ F (1 -2)_ 

GeophysicalS ignature: 

AssociatedDeposits: Porphyry-Mo-low-F __ Porphyry-Cu-Mo __ Cu-skarn __ 

Volcanic-hosted-Cu-As-Sb __ 

MaxScore: 3495 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model21b 

115 
Model22a 

116 

Worksheet for Numerical Model of Volcanic-hosted Cu-As-Sb 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Tertiary __ 

RockTypes: Andesite (3 -3) __ Dacite (3 -3) __ Flows (3 -3) __ Breccia (2 -2) __ Tuff (2 -2) __ 

TextureStructure: Massive __ Breccia-filling __ 

Alteration: Silicification __ 

Mineralogy: Pyrite (2 -5) __ Enargite (3 -5) __ Luzonite (2 -5) __ Tennantite (3 -4) __ 

Covellite (3 -3) __ Chalcocite (3 -3) __ Bornite (3 -3) __ Tetrahedrite (3 -4) __ 

Sphalerite (3 -3) __ 

GeochemicalSignature: As (3 -5) __ Sb (3 -3) __ Bi (2 -3) __ Cu (3 -5) __ Zn (2 -4) __ 

Au (2 -4)_ Ag (2 -5)_ B (1 -2)_ Sn (1 -2)_ S (2 -5)_ 

GeophysicalS ignature: 

AssociatedDeposits: Volcanic-hosted-Cu-As-Sb __ Porphyry-Cu-Mo __ Porphyry-Mo-low-F __ 

MaxScore: 1535 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Model22b 

Worksheet for Numerical Model of Au-Ag-Te veins 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Hypabyssal (5-5) __ Basalt (4 -4) __ Mafic-volcanic-rocks (4 -4) __ 

Shoshonite (5-1) __ 

TextureStructure: Veins __ 

Alteration: Propylitic __ 

Mineralogy: Tellurides (4 -5) __ Calaverite (3 -5) __ Sylvanite (3 -5) __ Hessite (3 -5) __ 

Coloradoite (3 -5) __ Pyrite (2 -5) __ Galena (2 -4) __ Sphalerite (2 -3) __ Tetrahedrite (2 -4) __ 

Stibnite (2 -3) __ 

GeochemicalSignature: Au (3 -5) __ Ag (3 -5) __ Te (3 -5) __ Cu (2 -4) __ Pb (2 -4) __ 

Zn (2 -3)_ Sb (2 -4)_ Hg (2 -4)_ F (2 -4)_ Ba (2 -3)_ Sr (2 -3)_ PGE (2 -2)_ 

Tl (1-2)_ 

GeophysicalSignature: 

AssociatedDeposits: Au-Ag-Te-veins __ Polymetallic-veins __ Polymetallic-replacement __ 

MaxScore: 1730 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalS ignature: __ GeophysicalS ignature: __ 

AssociatedDeposits: __ 

Model Score: 

117 
Model22c 

118 

Worksheet for Numerical Model of Polymetallic veins 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Regional-Metamorphic (5 -1) __ Felsic-plutonic (4 -2) __ 

Felsic-volcanic-rocks (4 -2) __ Mafic-volcanic-rocks (3 -2) __ 

TextureS tructure: Veins __ 

Alteration: Propylitic __ 

Mineralogy: Gold (2 -5) __ Carbonates (5-4) __ Pyrite (2 -5) __ Sphalerite (2 -5) __ 

Chalcopyrite (2 -4) __ Galena (2 -4) __ Arsenopyrite (2 -3) __ Tetrahedrite (2 -4) __ 

Tennantite (2 -4) __ Argentite (2 -3) __ Hematite (2 -3) __ 

GeochemicalSignature: Zn (2 -5) __ Cu (2 -5) __ Pb (2 -5)_ As (2 -4 ) __ Sb (2 -5) __ 

Au (2 -5)_ Ag (2 -5)_ Mn (2 -5)_ Ba (2 -4)_ B (1 -2)_ Ge (1 -2)_ Bi (1 -2)_ 

Te (1 -2)_ F (1 -2)_ 

GeophysicalSignature: 

AssociatedDeposits: Polymetallic-veins __ Porphyry-Cu-Mo __ Porphyry-Mo-low-F __ 

Polymetallic-replacement __ Placer-Au __ 

Max Score: 1910 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Basaltic Cu 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Proterozoic __ Triassic __ Jurassic __ Tertiary __ 

RockTypes: Mafic-volcanic-rocks (4 -1) __ Basalt (4 -1) __ Calcareous-Rocks (4 -1) __ 

Breccia(3 -1)_Tuff(2 -1)_Red-beds (3 -1)_ 

Tuffaceous-sandstone (2 -1) __ 

TextureStructure: Breccia __ Open-space-filling __ 

Alteration: Carbonates __ 

Mineralogy:. Copper (4 -5) __ Silver (2 -5) __ Chalcocite (3 -4) __ Bornite (2 -3) __ 

Chalcopyrite (2 -4) __ Pyrite (2 -3)_ 

GeochemicalSignature: Cu (4 -5) __ Ag (2 -4)_Zn (2 -3) __ B (1-2) __ Co (1-1) __ 

GeophysicalSignature: 

AssociatedDeposits: Basaltic-Cu __ Sediment-hosted-Cu __ Volcanogenic-Mn __ 

MaxScore: 1355 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model23 

119 
Model24a 

120 

Worksheet for Numerical Model of Cyprus massive sulfide 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Ophiolite (4 -1) __ Ultramafic-plutonic (4 -2) __ Basalt (4 -1) __ Diabase (2 -1) __ 

Fine-grained-metasedimentary-rocks (2 -1) __ Chert (2 -1) __ 

TextureStructure: Massive __ 

Alteration: Feldspar-destruction (5 -2) __ Silicification __ Chlorite __ 

Mineralogy: Pyrite (2 -5) __ Chalcopyrite (3 -5) __ Sphalerite (3 -4) __ Marcasite (2 -2) __ 

Pyrrhotite (2 -3) __ 

GeochemicalSignature: Mn (2 -4) __ Fe (2 -5) __ Cu (3 -5) __ Zn (3 -5) __ S (3 -5) __ 

Ag (2 -4)_ Au (2 -4)_ Co (2 -3)_ 

GeophysicalS ignature: 

AssociatedDeposits: Cyprus-massive-sulfide __ _ 

MaxScore: 1585 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 
Model24b 

Worksheet for Numerical Model ofBesshi massive sulfide 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Tuff (5-2) __ Shale (4 -!) __ Breccia (3 -1) __ Iron-formation (3 -1) __ 

Chert (3 -1)_ Sandstone (5-1)_ 

TextureStructure: Fine-grained __ Massive __ 

Alteration: Chloritization __ 

Mineralogy: Pyrite (3 -5) __ Pyrrhotite (3 -4) __ Chalcopyrite (3 -5) __ Sphalerite (3 -5) __ 

Magnetite (2 -4) __ Valleriite (2 -2) __ Galena (2 -3) __ Bornite (2 -3) __ Tetrahedrite (3 -3) __ 

Cobaltite (2 -2) __ Cubanite (2 -3) __ Stannite (2 -2) __ Molybdenite (2 -2) __ 

GeochemicalSignature: Cu (3 -5) __ Zn (3 -5) __ Co (2 -4)_ Ag (2 -5) __ Ni (2 -3)_ 

Cr (2 -3)_ Au (2 -4)_ 

GeophysicalSignature: 

AssociatedDeposits: Besshi-massive-sulfide __ 

MaxScore: 1400 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

121 
Model24c 

122 

Worksheet for Numerical Model of Volcanogenic Mn 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Chert (2 -1) __ Tuff (3 -2) __ Volcaniclastic-rocks (5-5) __ 

Felsic-volcanic-rocks (2 -2) __ Mafic-volcanic-rocks (2 -2) __ 

TextureStructure: Massive __ 

Alteration: Spilitic (5 -2) __ 

Mineralogy: Rhodochrosite (4 -4) __ Braunite (4 -2) __ Hausmannite (4 -2) __ Bementite (4 -2) __ 

Neotocite (2 -2) __ Alleghanyite (2 -2) __ Spessartine (2 -3) __ Rhodonite (4 -4) __ 

Maganite (4 -2) __ Pyrolusite (2 -2) __ Coronadite (2 -2) __ Cryptomelane (2 -2) __ 

Hollandite (2 -2) __ Todorokite (2 -2) __ 

GeochemicalSignature: Mn (4 -5) __ Zn (2 -3) __ Pb (2 -3) __ Cu (2 -3) __ Ba (2 -3) __ 

GeophysicalS ignature: 

AssociatedDeposits: Volcanogenic-Mn __ Kuroko-massive-sulfide __ 

MaxScore: 1790 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalS ignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Blackbird Co-Cu 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

Age Range: Precambrian __ Phanerozoic __ 

RockTypes: Metasedimentary-rocks (5 -5) __ Fine-grained-metasedimentary-rocks ( 4 -4 ) __ 

Mafic-metavolcanic-rocks (3 -3) __ Iron-formation (2 -1) __ 

TextureStructure: Massive __ Disseminated __ 

Alteration: Silicification __ Chloritization __ 

Mineralogy: Cobaltite (4 -5) __ Chalcopyrite (5 -5) __ Pyrite (2 -5) __ Pyrrhotite (2 -5) __ 

Arsenopyrite (2 -5) __ Magnetite (2 -5) __ Gold (2 -3) __ Silver (2 -3) __ 

GeochemicalSignature: Fe (2 -5) __ As (3 -5)_ B (2 -3) __ Co (4 -5) __ Cu (2 -5) __ 

Au (2 -3)_ Ag (2 -3)_ Mn (2 -4)_ 

GeophysicalS ignature: 

AssociatedDeposits: Blackbird-Co-Co __ Besshi -massive-sulfide __ 

Max Score: 1410 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model24d 

123 
Modei2Sa 

124 

Worksheet for Numerical Model of Hot-spring Au-Ag 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Tertiary __ Quaternary __ 

RockTypes: Rhyolite (5 -5) __ 

TextureStructure: Veins __ Stockwork __ Breccia __ 

Alteration: Silicification (5 -2) __ 

Mineralogy: Gold (3 -5)_ Pyrite (2 -5) __ Stibnite (3 -3) __ Realgar (3 -4) __ 

Arsenopyrite (2 -3) __ Sphalerite (2 -4) __ Chalcopyrite (2 -3) __ Fluorite (2 -3) __ 

GeochemicalSignature: Au (3 -5) __ As (3 -5) __ Sb (3 -4) __ Hg (2 -4) __ Tl (2 -4) __ 

Ag(3-5)_ 

GeophysicalS ignature: 

AssociatedDeposits: Hot-spring -Au-Ag __ Epithermal-quartz-veins __ Hot -spring-Hg __ 

Placer-Au __ 

MaxScore: 1700 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Creede epithermal veins 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Tertiary __ 

RockTypes: Felsic-volcanic-rocks (5 -5) __ Mafic-volcanic-rocks (5 -5) __ 

TextureStructure: Veins __ 

Alteration: Zoned (5 -2) __ 

Mineralogy: Galena (2 -5) __ Sphalerite (2 -5) __ Chalcopyrite (2 -5) __ 

Copper-sulfosalts (3 -5) __ Silver-sulfosalts (3 -5) __ Gold (3 -4) __ Tellurides (3 -3) __ 

Bornite (2 -2) __ Arsenopyrite (2 -2) __ 

GeochemicalSignature: Au (3 -4) __ As (3 -4) __ Sb (3 -4) __ Hg (2 -2) __ Pb (2 -5) __ 

Zn (2 -5)_ Cu (2 -5)_ 

GeophysicalS ignature: 

AssociatedDeposits: Creede-epithermal-veins __ Placer-Au __ Epithermal-quartz-alunite-Au __ 

Polymetallic-replacement __ 

MaxScore: 1835 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model25b 

125 
Model25c 

126 

Worksheet for Numerical Model of Comstock epithermal veins 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Tertiary __ 

RockTypes: Felsic-volcanic-rocks (5 -5) __ 

TextureStructure: Veins __ 

Alteration: Zoned (5 -2) __ 

Mineralogy: Argentite (3 -5) __ Gold (3 -5) __ Silver-sulfosalts (3 -4) __ Naumannite (2 -4) __ 

Galena (2 -4) __ Sphalerite (2 -4) __ Chalcopyrite (2 -4) __ Tellurides (3 -3) __ 

Hematite (2 -3) __ Arsenopyrite (2 -2) __ 

GeochemicalSignature: Au (3 -5) __ As (3 -4) __ Sb (3 -4) __ Hg (3 -3) __ Cu (2 -5) __ 

Ag (2 -5)_ Ph (2 -5)_ 

GeophysicalSignature: 

AssociatedDeposits: Comstock -epithermal-veins __ Placer-Au __ Epithermal-quartz-alunite-Au __ 

MaxScore: 1655 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Sado epithermal veins 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Tertiary __ 

RockTypes: Felsic-volcanic-rocks (5 -5) __ 

TextureStructure: Veins __ 

Alteration: Silicification __ 

Mineralogy: Gold (3 -5) __ Argentite (3 -4) __ Chalcopyrite (2 -5) __ Sulfosalts (3 -5) __ 

Tellurides (3 -4) __ Galena (2 -4) __ Sphalerite (2 -4) __ 

GeochemicalSignature: Au (3 -5) __ Ag (2 -5) __ Cu (2 -5) __ 

GeophysicalSignature: 

AssociatedDeposits: Sado-epithermal-veins __ Placer-Au __ Quartz-alunite-Au __ 

MaxScore: 1100 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model25d 

127 
Model25e 

128 

Worksheet for Numerical Model of Epithermal quartz-alunite Au 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerowic __ 

RockTypes: Felsic-volcanic-rocks (5 -5) __ 

TextureStructure: Veins __ Pipe __ 

Alteration: Zoned (5-2) __ 

Mineralogy: Gold (3 -5) __ Enargite (3 -5) __ Pyrite (2 -5) __ Silver-sulfosalts (3 -5) __ 

Chalcopyrite (2 -4) __ Bornite (2 -3) __ Tellurides (3 -3) __ Galena (2 -4) __ Sphalerite (2 -4) __ 

Huebnerite (2 -2) __ 

GeochemicalSignature: Au (3 -5) __ As (3 -5) __ Cu (2 -5) __ Te (3 -3) __ W (2 -1) __ 

GeophysicalS ignature: 

AssociatedDeposits: Epithermal-quartz-alunite-Au __ Porphyry-Cu __ Polymetallic-replacement __ 

Volcanic-hosted-Cu-As-Sb __ 

MaxScore: 1730 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Volcanogenic U 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Archean __ Proterozic __ Paleozoic __ Mesozoic ___ Tertiary __ 

RockTypes: Felsic-volcanic-rocks (5-5) __ Mafic-volcanic-rocks (5-5) __ Alkali-rhyolite (3 -2) __ 

Trachyte (3 -2) __ 

TextureStructure: Breccia __ Open-space-filling __ 

Alteration: Kaolinite __ Montmorillonite __ Alunite __ Silicification (4 -1) __ Adularia (4 -1) __ 

Mineralogy: Coffinite (4 -5) __ Uraninite (4 -5) __ Brannerite (4 -5) __ Pyrite (2 -5) __ 

Realgar (2 -3) __ Orpiment (2 -3) __ Leucoxene (2 -3) __ Molybdenite (2 -4 ) __ 

Fluorite (2 -4) __ Quartz (1 -4)_ Adularia (2 -4)_ Barite (1 -3)_ 

Model25f 

GeochemicalSignature: U (4 -5)_Hg (3 -4) __ As (3 -4)_ Sb (3 -4) __ F (3 -5) __ Mo (3 -5) __ 

W (2 -2)_REE(2-3)_Li (3 -4)_Ba(1-1)_ 

GeophysicalSignature: 

AssociatedDeposits: Volcanogenic-U __ Sandstone-U __ Fluorspar __ 

MaxScore: 2515 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

129 
Model 25g 

130 

Worksheet for Numerical Model of Epithermal Mn 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Tertiary __ 

RockTypes: Tuff(4 -3) __ Breccia (3 -2) __ Agglomerate (2 -l) __ Rhyolite (3 -2) __ 

TextureS tructure: Veins __ 

Alteration: Kaolin __ 

Mineralogy: Rhodochrosite (4 -5) __ Manganocalcite (4 -5) __ Barite (2 -5) __ Zeolite (2 -5) __ 

GeochemicalSignature: Mn (4 -5) __ Fe (2 -5) __ P (3 -4) __ W (2 -3) __ 

GeophysicalS ignature: 

AssociatedDeposits: Epithermal-Mn __ Epithermal-Au-Ag __ 

MaxScore: 1025 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Rhyolite-hosted Sn 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Tertiary __ 

RockTypes: Alkali-rhyolite (4 -3) __ Rhyolite (5-3) __ 

TextureStructure: Veinlets __ 

Alteration: 

Mineralogy: Cassiterite (4 -5) __ Hematite (2 -5) __ Cristobalite (3 -5) __ Fluorite (4 -3) __ 

Tridymite (3 -5)_ Opal (2 -5) __ Chalcedony (2 -5)_. Beudantite (3 -2) __ 

Mimetite (3 -2) __ Adularia (3 -4) __ Durangite (2 -2) __ Topaz (4 -3) __ 

GeochemicalSignature: Sn (4 -5) __ 

GeophysicalSignature: 

AssociatedDeposits: Rhyolite-hosted-Sn __ Climax-Mo __ 

MaxScore: 1120 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model25h 

131 
Model25i 

132 

Worksheet for Numerical Model of Volcanic-hosted magnetite 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Mesozoic __ Cenozoic __ 

RockTypes: Alkaline-volcanic-rocks (5-3) __ Mafic-volcanic-rocks (4 -4) __ Felsic-plutonic (2 -1) __ 

TextureS tructure: Massive-replacement __ 

Alteration: Calc-silicates __ 

Mineralogy: Magnetite (4 -5) __ Apatite (2 -5) __ 

GeochemicalSignature: Fe (4 -5) __ P (4 -5) __ V (4 -4) __ Ba (2 -3) __ F (2 -3) __ Bi (2 -3) __ 

Cu (2 -3)_ Co (2 -5)_ 

GeophysicalSignature: Magnetic-high __ 

AssociatedDeposits: Volcanic-hosted-magnetite __ Sedimentary-Fe __ 

MaxScore: 1110 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalS ignature: __ 

AssociatedDeposits: __ 

Model Score: 
Model26a 

Worksheet for Numerical Model of Carbonate-hosted Au-Ag 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Carbonaceous-limestone (4 -2) __ Carbonaceous-dolomite (4 -2) __ 

Carbonaceous-shale (4 -2) __ 

TextureS tructure: Replacement __ 

Alteration: Amorphous-carbon __ 

Mineralogy: Gold (4 -5) __ Pyrite (2 -5) __ Realgar (2 -5) __ Orpiment (2 -5) __ 

Arsenopyrite (2 -3) __ Cinnabar (2 -3) __ Fluorite (2 -3) __ Barite (2 -3) __ Stibnite (2 -3) __ 

GeochemicalSignature: Au (4 -5) __ Ag (2 -5) __ As (3 -5) __ Hg (2 -4) __ W (2 -4) __ 

Mo (2 -2)_ Sb (2 -4)_ Tl (2 -4)_F (2 -2)_ NH3 (2 -3)_ C (2 -5)_ Ba (2 -3)_ 

GeophysicalSignature: 

AssociatedDeposits: Carbonate-hosted-Au-Ag __ W-Mo-skam __ Porphyry-Mo __ Placer-Au __ 

Stibnite-barite-veins __ 

MaxScore: 1835 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

133 
Model27a 

134 

Worksheet for Numerical Model of Hot-spring Hg 

DepositYrospect,orOccurrence: 

Location: 

Description: 

AgeRange: Tertiary __ Cretaceous __ 

RockTypes: Siliceous-sinter (5-5) __ Mafic-volcanic-rocks (3 -1) __ Tuff (3 -1) __ 

Tuff-breccia (2 -1) __ 

TextureStructure: Vein __ Disseminated __ 

Alteration: Kaolinization __ 

Mineralogy: Cinnabar (5 -5) __ Mercury (5-3) __ Marcasite (2 -2) __ Stibnite (2 -1) __ 

GeochemicalSignature: Hg (4 -5)_ As (3 -5)_ Sb (3 -5)_ Au (2 -3)_ B (2 -3)_ 

Geophysical$ ignature: 

AssociatedDeposits: Hot-spring-Hg __ Hot-spring-Au __ 

MaxScore: 1115 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Almaden Hg 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Volcaniclastic-rocks (5-5) __ Tuff (3 -2) __ Vent-breccia (3 -2) __ 

TextureStructure: Disseminated __ 

Alteration: 

Mineralogy: Cinnabar (4 -5) __ Mercury (5-5) __ Pyrite (2 -3) __ 

GeochemicalSignature: Hg (4 -5) __ As (3 -4) __ Sb (3 -4) __ B (2 -3) __ 

GeophysicalSignature: 

AssociatedDeposits: Almaden-Hg __ Stibnite-veins __ 

MaxScore: 910 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model27b 

135 
Model27c 

136 

Worksheet for Numerical Model of Silica-carbonate Hg 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Tertiary __ 

RockTypes: Serpentinite (4 -4) __ Siltstone (3 -2) __ Graywacke (3 -2) __ 

TextureStructure: Replacement __ 

Alteration: Silicification (5 -2) __ 

Mineralogy: Cinnabar (4 -5) __ Mercury (5 -5) __ Pyrite (2 -5) __ Stibnite (3 -4) __ 

Chalcopyrite (2 -4) __ Sphalerite (2 -4) __ Galena (2 -4) __ Bornite (2 -3) __ 

GeochemicalSignature: Hg (4 -5) __ Sb (3 -4) __ Cu (2 -3) __ Zn (2 -3) __ B (2 -3) __ 

GeophysicalSignature: 

AssociatedDeposits: Silica-carbonate-Hg __ S tibnite-veins __ 

MaxScore: 1475 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Simple Sb deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Rock-Types (5-5) __ 

TextureStructure: Vein __ Massive __ 

Alteration: Silicification __ Sericitization __ Argillic __ 

Mineralogy: Stibnite (4 -5) __ Pyrite (2 -3) __ 

GeochemicalSignature: Sb (2 -5) __ Fe (2 -4) __ As (2 -4) __ Au (2 -4) __ Ag (2 -4) __ 

Hg (2 -3)_ W (2 -3)_ Pb (2 -3)_ Zn (2 -3)_ 

GeophysicalSignature: 

AssociatedDeposits: Simple-Sb __ Low-sulfide-Au-quartz-veins __ Hot-spring-Au-Ag __ 

Carbonate-hosted-Au-Ag __ Placer-Au __ 

MaxScore: 1585 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalS ignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model27d 

137 
Model27e 

138 

Worksheet for Numerical Model of Disseminated Sb deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Rock-Types (5-5) __ 

TextureStructure: Vein __ Disseminated __ 

Alteration: Silicification __ Sericitization __ Argillic __ 

Mineralogy: Stibnite (2 -5) __ Pyrite (2 -4) __ 

GeochemicalSignature: Sb (4 -5) __ Fe (2 -3) __ As (3 -5) __ Au (2 -5) __ Hg (2 -3) __ 

W (2 -3)_ Pb (2 -3)_ Zn (2 -3)_ 

GeophysicalSignature: 

AssociatedDeposits: Disseminated-Sb __ Simple-Sb __ Low-sulfide-Au-quartz-veins __ 

Hot-spring-Au-Ag __ Carbonate-hosted-Au.,.Ag __ Placer-Au __ 

MaxScore: 1720 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
~fl 

Worksheet for Numerical Model of Kuroko massive sulfide 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Archean __ Proterozoic __ Phanerozoic __ 

RockTypes: Felsic-volcanic-rocks (5 -5) __ Mafic-volcanic-rocks (5 -5) __ 

Volcaniclastic-rocks (4 -1) __ Pelites (3 -1) __ Shale (2 -1) __ 

TextureStructure: Massive __ Stockwork __ Breccia __ 

Alteration: Zeolites __ Montmorillonite __ Silicification __ 

Mineralogy: Pyrite (2 -5) __ Sphalerite (3 -5) __ Chalcopyrite (3 -5) __ Pyrrhotite (2 -3) __ 

Model28a 

Galena (2 -4) __ Barite (2 -2) __ Tetrahedrite (2 -4) __ Tennantite (2 -4) __ Bornite (2 -3) __ 

Magnetite (1 -3) __ Gahnite (2 -3) __ Gypsum (1 -2) __ Anhydrite (1 -2) __ 

GeochemicalSignature: Pb (4 -5)_ Au (3 -3) __ Mg (2 -3) __ Zn (4 -5) __ Cu (3 -5) __ 

Ba (2 -2)_ As (2 -4)_ Ag (4 -5)_ Se (2 -2)_ Sn (2 -4)_ Fe (2 -5)_ 

GeophysicalSignature: 

AssociatedDeposits: Kuroko-massive-sulfide __ Epithermal-quartz-adularia-veins __ 

Volcanogenic.Mn __ Algoma.Fe __ 

MaxScore: 2110 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

139 
Model28b 

140 

Worksheet for Numerical Model of Algoma Fe 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Archean __ 

RockTypes: Iron-formation (5-5) __ Mafic-volcanic-rocks (3 -2) __ Felsic-volcanic-rocks (3 -2) __ 

Volcaniclastic-rocks (4 -4) __ 

TextureStructure: Banded __ 

Alteration: 

Mineralogy: Magnetite (4 -5) __ Hematite (4 -5) __ Siderite (2 -3) __ 

GeochemicalSignature: Fe (2 -5) __ Mn (2 -3) __ 

GeophysicalSignature: Magnetic-high __ 

AssociatedDeposits: Algoma-Fe __ Kuroko-massive-sulfide __ Homestake-Au __ 

Max Score: 1010 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Quartz pebble conglomerate Au-U 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ 

RockTypes: Conglomerate (5 -5) __ Sandstone (3 -1 ) __ 

TextureStructure: Replacement __ 

Alteration: 

Mineralogy: Gold (3 -5) __ Pyrite (2 -4) __ Uraninite (3 -5) __ Brannerite (3 -5) __ 

Zircon (2 -3) __ Chromite (2 -3) __ Monazite (2 -3) __ Leucoxene (2 -3) __ 

GeochemicalSignature: Au (3 -5)_ U (3 -4)_ PGE (2 -4)_ REE (2 -3)_ Zr (2 -3) __ 

As (2 -2)_ C (2 -4)_ 

GeophysicalSignature: Radioactive-anomaly __ 

AssociatedDeposits: Quartz-pebble-conglomerate-Au-U __ Placer-Au __ 

Low-sulfide-Au-quartz-veins __ Homestake-Au __ Superior-Fe __ 

MaxScore: 1520 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model29a 

141 
Model29b 

142 

Worksheet for Numerical Model of Olympic Dam Cu-U-Au 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ 

RockTypes: Alkali-granite (5 -2) __ Breccia (5-3) __ Felsic-volcanic-rocks (3 -2) __ Tuff (2 -1) __ 

TextureStructure: Breccia __ Veins __ 

Alteration: Hematite __ Chlorite __ Sericite __ Quartz __ 

Mineralogy: Hematite (2 -5) __ Bornite (2 -3) __ Chalcopyrite (2 -5) __ Chalcocite (2 -5) __ 

Fluorite (2 -4 ) __ Barite (2 -4 ) __ 

GeochemicalSignature: Cu (4 -5) __ U (4 -4) __ Co (2 -3) __ Au (3 -5) __ Ag (2 -5) __ 

REE (2 -3)_ F (2 -3)_ Ba (2 -3)_ Fe (2 -5)_ 

Geophysical Signature: Radioactive-anomaly __ 

AssociatedDeposits: Olympic-Dam-Cu-D-Au __ 

MaxScore: 1425 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalS ignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Sandstone-hosted Pb-Zn 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Proterozoic __ Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Sandstone (5-5) __ Conglomerate (3 -1) __ Siltstone (3 -1) __ 

TextureStructure: Stratiform __ 

Alteration: Recrystallization __ 

Mineralogy: Galena (4 -5) __ Sphalerite (4 -5) __ Pyrite (2 -4) __ Barite (2 -3) __ 

Fluorite (2 -3) __ 

GeochemicalSignature: Pb (4 -5) __ Zn (4 -5) __ Ba (3 -3) __ C (2 -3) __ F (2 -3) __ 

Ag(2-4)_Ni(1-1)_As(1-2)_Sb(1-2)_Bi(1-1)_ 

GeophysicalS ignature: 

AssociatedDeposits: Sandstone-hosted-Pb-Zn __ Sediment-hosted-Co __ 

MaxScore: 1190 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

ModeiJOa 

143 
Model JOb 

144 

Worksheet for Numerical Model of Sediment-hosted Cu 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

Age Range: Proterozoic __ Phanerozoic __ 

RockTypes: Red-beds (5-5) __ Green-shale (3 -1) __ Sandstone (5-5) __ Shale (3 -2) __ 

TextureStructure: Stratiform __ 

Alteration: Reduction (5-3) __ 

Mineralogy: Chalcocite (4 -4) __ Pyrite (2 -4) __ Bornite (3 -4) __ Silver (2 -4) __ 

GeochemicalSignature: Cu (4 -5) __ Ag (3 -5) __ Pb (2 -3)_ Zn (2 -3)_ U (2 -4) __ 

Ga (1 -2)_ V (2 -2)_ Co (1 -2)_ Mo (2 -3)_ C (2 -4)_ 

GeophysicalS ignature: 

AssociatedDeposits: Sediment-hosted-Cu __ Sandstone-U __ Basalt-Cu __ Kipushi-Cu-Pb-Zn __ 

MaxScore: 1820 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Sandstone U 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Devonian __ Carboniferous __ Permian __ Mesozoic __ Tertiary __ 

RockTypes: Sandstone (5-5) __ Feldspathic-sandstone (4 -4) __ Tuffaceous-sandstone (3 -3) __ 

Mudstone (3 -1 ) __ 

TextureStructure: Stratiform __ 

Alteration: Reduction __ Leaching __ Oxidation __ 

Mineralogy: Uraninite (4 -5) __ Coffinite (4 -5) __ Pyrite (2 -5) __ 

GeochemicalSignature: U (4 -5) __ V (2 -5) __ C (3 -5) __ Mo (2 -4) __ Se (2 -5) __ 

Cu (2 -4)_ Ag (2 -5)_ 

GeophysicalSignature: Radioactive-anomaly __ 

AssociatedDeposits: Sandstone-U __ Sediment-hosted-V __ Sediment-hosted-Cu __ 

MaxScore: 1505 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model JOe 

145 
Model31a 

146 

Worksheet for Numerical Model of Sedimentary exhalative Zn-Pb 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Proterozoic __ Phanerozoic __ 

RockTypes: Shale (5 -5) __ Black-shale ( 4 -4 ) __ Chert (2 -1 ) __ Calcareous-Rocks ( 4 -2) __ 

Turbidites (2 -1 ) __ Tuffites (2 -1 ) __ 

TextureStructure: Disseminated __ 

Alteration: Tourmalinization __ Leaching __ Albitization __ Chloritization __ 

Mineralogy: Pyrite (2 -4) __ Pyrrhotite (2 -3) __ Sphalerite (4 -5) __ Galena (4 -5) __ 

Barite (2 -3) __ Chalcopyrite (3 -4) __ Marcasite (2 -4) __ Arsenopyrite (2 -3) __ 

Bismuthinite (2 -2) __ Molybdenite (1-2) __ Enargite (1 -1) __ 

GeochemicalSignature: Zn (4 -5) __ Ag (3 -5)_ Pb (4 -5) __ Mn (2 -4) __ B (2 -3) __ 

Ba (2 -4)_ Co (1 -2)_ Cu (3 -5)_ Mo (2 -2)_ Sn (1 -2)_ As (2 -3)_ 

Sb (1-2)_Bi(1-1)_S (2 -5)_C (2 -4)_NH3 (2-3)_ 

GeophysicalSignature: 

AssociatedDeposits: Sedimentary-exhalative-Zn-Pb __ Bedded-barite __ 

MaxScore: 1970 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

r 
Worksheet for Numerical Model of Bedded barite 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Proterozoic __ Phanerozoic __ 

RockTypes: Shale (5-2) __ Chert (4 -2) __ Calcareous-Rocks (3 -2) __ Argillite (2 -1) __ 

Greenstone (2 -1) __ Sandstone (2 -1) __ 

TextureStructure: Stratiform __ 

Alteration: Barite __ 

Mineralogy: Barite (5 -5) __ Witherite (2 -3) __ Pyrite (2 -3) __ Galena (2 -3) __ 

Sphalerite (2 -3) __ 

GeochemicalSignature: Ba (5-5) __ S (2 -5) __ C (2 -4) __ Zn (2 -3) __ 

GeophysicalSignature: Gravity-high __ 

AssociatedDeposits: Bedded-barite __ Sedimentary -exhalative-Zn-Pb __ 

MaxScore: 1155 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model31b 

147 
Model 31c 

148 

Worksheet for Numerical Model of Emerald veins 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Cretaceous __ Tertiary __ 

RockTypes: Black-shale (4 -4) __ Calcareous-Rocks (2 -2) __ Evaporites (2 -2) __ 

TextureStructure: Banded __ Veins __ 

Alteration: Hornfels __ 

Mineralogy: Emerald (5 -5) __ Beryl (3 -5) __ Pyrite (2 -5) __ Fluorite (2 -5) __ Rutile (2 -5) __ 

GeochemicalSignature: Be (3 -5)_ Na (2 -5)_ Mg (2 -4)_ REE (2 -2) __ Cs (2 -3) __ 

F(2-3)_ 

GeophysicalSignature: 

AssociatedDeposits: Emerald-veins __ 

MaxScore:875 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 
Worksheet for Numerical Model of Southeast Missouri Pb-Zn 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Cambrian __ Ordovician __ 

RockTypes: Dolomite (5 -5) __ 

TextureS tructure: Open-space-filling __ 

Alteration: Dolomitization __ 

Mineralogy: Galena (3 -5) __ Sphalerite (3 -5) __ Chalcopyrite (3 -4) __ Pyrite (2 -5) __ 

Marcasite (2 -4) __ 

GeochemicalSignature: Pb (3 -5) __ Zn (3 -5) __ Cu (2 -5) __ Mo (2 -4) __ Ag (2 -4)_ 

Co (2 -4)_Ni(2 -4)_Cd(2 -4)_As (1-2)_Sb (1-1)_F(l-2)_ 

Br (1 -3)_ C (1 -3)_ 

GeophysicalSignature: 

AssociatedDeposits: Southeast-Missouri-Pb-Zn __ Volcanic-hosted-magnetite __ 

MaxScore: 1115 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model32a 

149 
Model32b 

150 

Worksheet for Numerical Model of Appalachian Zn 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Proterozoic __ Paleozoic __ Triassic __ 

RockTypes: Carbonate-rocks (5-5) __ 

TextureStructure: Open-space-filling __ 

Alteration: Silicification __ 

Mineralogy: Sphalerite (4 -5) __ Pyrite (2 -4) __ Marcasite (2 -4) __ 

GeochemicalSignature: Zn (4 -5) __ Pb (4 -3) __ Mg (2 -5) __ Ba (2 -3) __ Cd (2 -4) __ 

F(2-3)_ 

GeophysicalSignature: 

AssociatedDeposits: Appalachian-Zn __ 

MaxScore: 785 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Model32c 

Worksheet for Numerical Model of Kipushi Cu-Pb-Zn 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerowic __ 

RockTypes: Calcareous-Rocks (5-5) __ Dolomite (5-5) __ Breccia (4 -4) __ Shale (3 -2) __ 

TextureS tructure: Massive-replacement __ 

Alteration: Dolomitization (4 -2) __ Siderite __ Silicification __ 

Mineralogy: Pyrite (2 -5) __ Bornite (2 -5) __ Chalcocite (2 -4) __ Chalcopyrite (2 -4) __ 

Carrollite (2 -4) __ Sphalerite (2 -4) __ Tennantite (2 -5) __ Galena (2 -3) __ Enargite (2 -2) __ 

GeochemicalSignature: Cu (2 -5) __ Zn (2 -5) __ Pb (2 -5) __ As (2 -5) __ Co (2 -3) __ 

Ag (2 -5)_Ge (2 -3)_ Mo (2 -3)_W (2 -3)_Sn (2 -3)_Bi (2 -3)_ U (2 -4)_ 

V (2 -3)_ Mg (2 -5)_ Ga (2 -3)_ 

GeophysicalSignature: 

AssociatedDeposits: Kipushi-Cu-Pb-Zn __ Sedimentary-Cu __ U-veins __ 

Sedimentary-exhalative-Zn-Pb __ 

MaxScore: 2175 

Partial Scores 

Age Range: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

151 
Model34a 

152 

Worksheet for Numerical Model of Superior Fe 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Proterozoic __ 

RockTypes: Iron-formation (5 -5) __ Sandstone (2 -2) __ Shale (2 -2) __ Dolomite (2 -2) __ 

TextureStructure: Banded __ 

Alteration: 

Mineralogy: Hematite (2 -5) __ Magnetite (2 -5) __ Siderite (2 -3) __ 

GeochemicalSignature: Fe (2 -5) __ Mn (2 -3) __ 

Geophysical Signature: Magnetic-high __ 

AssociatedDeposits: Superior-Fe __ Sedimentary-Mn __ 

MaxScore: 740 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GcophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Sedimentary Mn 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

Age Range: Precambrian __ Phanerozoic __ 

RockTypes: Calcareous-Rocks (5-5) __ Clay (3 -2) __ Shell-rocks (2 -2) __ 

TextureStructure: Oolites __ Pisolites __ 

Alteration: Supergene __ 

Mineralogy: Mn-carbonates (4 -5) __ Mn-oxides (4 -5) __ Glauconite (2 -3) __ 

GeochemicalSignature: Mn (4 -5) __ V (2 -4) __ 

GeophysicalSignature: 

AssociatedDeposits: Sedimentary-Mn __ Sediment-hosted-Cu __ 

MaxScore: 890 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model34b 

153 
Model34c 

154 

Worksheet for Numerical Model of Upwelling-type phosphate deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Paleozoic __ Mesozoic __ Tertiary __ 

RockTypes: Phosphorite (5-5) __ Calcareous-Rocks (3 -2) __ Petites (2 -1) __ Chert (2 -1) __ 

TextureStructure: Pellets __ Nodules __ 

Alteration: 

Mineralogy: Apatite (3 -5) __ Fluorapatite (3 -5) __ Siderite (2 -4) __ Carnotite (2 -4) __ 

GeochemicalSignature: P (4 -5)_ N (4 -3)_ F (2 -5)_ C (2 -4) __ U (2 -5) __ 

GeophysicalSignature: Radioactive-anomaly __ 

AssociatedDeposits: Upwelling -type-phosphate __ Sedimentary-Mn __ 

MaxScore: 965 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Warm-current-type phosphate deposits 

Deposi t,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Cretaceous __ Tertiary __ 

RockTypes: Phosphatic-limestone (5 -2) __ Phosphative-sandstone (5-2) __ 

Diatomaceous-material (2 -2) __ Chert (2 -2) __ 

TextureS tructure: Pellets __ Fossil-fragments __ 

Alteration: 

Mineralogy: Fluorapatite (4 -5) __ 

GeochemicalSignature: P (4 -5)_ C (2 -3)_ U (2 -5)_ N (4 -3)_ F (2 -5)_ 

GeophysicalS ignature: 

AssociatedDeposits: Warm-current-type-phosphate __ 

MaxScore: 730 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model34d 

155 
Model36a 

156 

Worksheet for Numerical Model of Low-sulfide Au-quartz veins 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Greenstone (5 -5) __ Metasedimentary-rocks (5 -2) __ 

Mafic-metavolcanic-rocks (4 -2) __ Graywacke (4 -2) __ Chert (2 -1) __ 

TextureStructure: Veins __ Shear-zone __ 

Alteration: Silicification (5 -2) __ Siderite __ Ankerite __ Albite __ Carbonates __ 

Mineralogy: Gold (5 -5)_ Pyrite ( 4 -5)_ Galena (3 -3) __ Chalcopyrite (3 -3) __ 

Arsenopyrite (3 -3) __ Pyrrhotite (2 -1) __ 

GeochemicalSignature: Au ( 4 -5) __ As ( 4 -5) __ . Ag ( 4 -5) __ Pb (3 -4 ) __ Zn (2 -3) __ 

Te(1-2)_ 

GeophysicalSignature: 

AssociatedDeposits: Low -sulfide-Au-quartz-veins __ Placer-Au-PGE __ Kuroko-massive-sulfide __ 

Homes take-Au __ 

MaxScore: 2370 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model ofHomestake Au 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Archean __ 

RockTypes: Metavolcanic-rocks (5-5) __ Komatiite (2 -2) __ Volcaniclastic-rocks (2 -2) __ 

Iron-formation (5-5) __ Felsic-plutonic (3 -3) __ 

TextureStructure: Bedded __ Veins __ Lenses __ 

Alteration: Zoned (5 -2) __ 

Mineralogy: Gold (4 -5) __ Pyrite (2 -5) __ Pyrrhotite (2 -4) __ Arsenopyrite (3 -4) __ 

Magnetite (2 -4) __ Sphalerite (2 -3) __ Chalcopyrite (2 -3) __ 

GeochemicalSignature: Au (4 -5) __ Fe (2 -3) __ As (3 -4) __ B (2 -4) __ Sb (3 -4) __ 

PGE (2 -3)_ Bi (3 -3)_ Hg (3 -3)_ 

GeophysicalSignature: 

AssociatedDeposits: Homes take-Au __ Kuroko-massive-sulfide __ Algoma-Fe __ 

Low-sulfide-Au-quartz-veins __ 

MaxScore: 1940 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model36b 

157 
Model37a 

158 

Worksheet for Numerical Model of Unconformity U-Au 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Proterozoic __ 

RockTypes: Fine-grained-metasedimentary-rocks ( 4 -4 ) __ Carbonaceous-pelites ( 4 -4 ) __ 

Carbonate-rocks (2 -1 ) __ 

TextureStructure: Breccia-filling __ Veins __ Disseminated __ 

Alteration: Chloritization __ 

Mineralogy: Pitchblende (4 -5) __ Uraninite (4 -5) __ Coffinite (4 -5) __ Pyrite (2 -3) __ 

Chalcopyrite (2 -4) __ Galena (2 -4) __ Sphalerite (2 -3) __ Arsenopyrite (2 -3) __ 

Niccolite (2 -3) __ 

GeochemicalSignature: U (4 -5) __ Mg (2 -4) __ P (2 -4) __ 

GeophysicalSignature: Radioactive-anomaly __ Electromagnetic-anomaly __ 

Associated Deposits: Unconformity-U-Au __ 

MaxScore: 1030 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

r 
Worksheet for Numerical Model of Gold on flat faults 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Breccia (5-5) __ Mylonite (3 -3) __ Igneous (2 -4) __ 

TextureStructure: Stockwork __ Veins __ Breccia __ 

Alteration: Iron-oxides __ Silicification __ Carbonate-rocks __ 

Mineralogy: Gold (4 -5) __ Hematite (2 -5) __ Chalcopyrite (2 -4) __ 

GeochemicalSignature: Au (4 -5) __ Cu (2 -5) __ Fe (2 -4) __ F (3 -4) __ Ba (2 -3) __ 

GeophysicalS ignature: 

AssociatedDeposits: Gold-on-flat-faults __ 

Max Score: 1015 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

Model37b 

159 
Model38a 

160 

Worksheet for Numerical Model of Lateritic Ni 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Ultramafic-plutonic (5 -5) __ Serpentinite (3 -2) __ 

TextureS tructure: Pisolites __ 

Alteration: 

Mineralogy: Garnierite (4 -5) __ Goethite (3 -5) __ 

GeochemicalSignature: Ni (2 -5) __ Co (2 -5) __ Cr (2 -5) __ 

GeophysicalSignature: 

AssociatedDeposits: Lateritic-Ni __ Podiform-chromite __ Serpentine-hosted-asbestos __ 

Placer-PGE-Au __ Placer-Au-PGE __ 

MaxScore: 1165 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalS ignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Worksheet for Numerical Model of Laterite-type bauxite deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Cretaceous __ Cenozoic __ 

RockTypes: Aluminous-silicate-rocks (5-5) __ 

TextureStructure: Pisolites __ Massive __ Nodules __ 

Alteration: Bauxite (5-5) __ 

Mineralogy: Gibbsite (4 -5) __ Boehmite (4 -4) __ Hematite (2 -4) __ Goethite (3 -4) __ 

Anatase (2 -4 ) __ 

GeochemicalSignature: AI (4 -5) __ Ga (3 -3) __ 

GeophysicalS ignature: 

AssociatedDeposits: Laterite-type-bauxite __ 

MaxScore: 1055 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model38b 

161 
Model38c 

162 

Worksheet for Numerical Model of Karst-type bauxite deposits 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Paleozoic __ Mesozoic __ Cenozoic __ 

RockTypes: Felsic-volcanic-rocks (2 -2) __ Aluminous-silicate-rocks (4 -2) __ 

TextureStructure: Pisolites __ Massive __ Nodules __ 

Alteration: Bauxite (5-5) __ 

Mineralogy: Gibbsite (4 -5) __ Boehmite (4 -4) __ Hematite (2 -4) __ Goethite (3 -4) __ 

Anatase (2 -4 ) __ 

GeochemicalSignature: AI (4 -5) __ Ga (4 -3) __ 

GeophysicalSignature: 

AssociatedDeposits: Karst-type-bauxite __ 

MaxScore: 1085 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalS ignature: __ GcophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 
Worksheet for Numerical Model of Placer Au-PGE 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Cenozoic __ 

RockTypes: Gravel (5-5) __ Conglomerate (5-1) __ 

TextureStructure: Placer __ 

Alteration: 

Mineralogy: Gold (4 -5) __ Magnetite (2 -5) __ Ilmenite (2 -4) __ 

GeochemicalSignature: Au (4 -5) __ Ag (2 -5) __ As (2 -4) __ Hg (2 -3) __ Sb (2 -2) __ 

Cu (2 -3)_ Fe (2 -4)_ S (2 -2)_ 

GeophysicalSignature: 

AssociatedDeposits: Placer-Au-PGE __ Porphyry-Co __ Co-skarn __ Polymetallic-replacement __ 

Low-sulfide-Au-quartz-veins __ 

MaxScore: 1390 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 

Model39a 

163 
Model39b 

164 

Worksheet for Numerical Model of Placer PGE-Au 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Cenozoic __ 

RockTypes: Gravel (5 -5) __ Conglomerate (5-1) __ 

TextureStructure: Placer __ 

Alteration: 

Mineralogy: PGE (4 -5) __ Gold (4 -5) __ Magnetite (2 -5) __ Chromite (2 -4) __ Ilmenite (2 -4) __ 

GeochemicalSignature: Au (4 -4)_ PGE (4 -5)_ Ag (2 -4) __ As (2 -4) __ Hg (2 -3) __ Sb (2 -2)_ 

Cu (2 -3)_Fe (2-4)_S (2 -2)_Cr(2 -5)_ 

GeophysicalSignature: 

AssociatedDeposits: Placer-PGE-Au __ Alaska-PGE __ 

MaxScore: 1120 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: __ 
Model39c 

Worksheet for Numerical Model of Shoreline placer Ti 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Sand (5-5) __ 

TextureStructure: Placer __ 

Alteration: 

Mineralogy: Ilmenite (4 -5) __ Rutile (3 -5) __ Zircon (2 -4) __ 

GeochemicalSignature: Ti (4 -5) __ Zr (2 -5) __ REE (2 -5) __ Th (2 -5) __ U (2 -5) __ Fe (2 -4) __ 

GeophysicalSignature: Radioactive-anomaly __ Induced-polarization-anomaly __ 

AssociatedDeposits: Shoreline-placer-Ti __ 

MaxScore: 720 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 

165 
Model39d 

166 

Worksheet for Numerical Model of Diamond placers 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Cenozoic __ 

RockTypes: Gravel (5 -5) __ Conglomerate (2 -1) __ 

TextureStructure: Placer __ 

Alteration: 

Mineralogy: Diamond (5 -5) __ Bort (5 -5) __ Ballas (5 -5) __ 

GeochemicalSignature: Cr (2 -3) __ Ti (2 -5) __ Mn (2 -4) __ Ni (2 -4) __ Co (2 -3) __ 

PGE (2 -4)_ Ba (2 -3)_ Nb (2 -4)_ Mg (2 -3)_ 

GeophysicalSignature: 

AssociatedDeposits: Diamond-placers __ Diamond-pipes __ 

Max Score: 1000 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model Score: 
Worksheet for Numerical Model of Alluvial placer Sn 

Deposit,Prospect,or Occurrence: 

Location: 

Description: 

AgeRange: Precambrian __ Phanerozoic __ 

RockTypes: Gravel (5-5) __ Conglomerate (2 -1} __ 

TextureStructure: Placer __ 

Alteration: 

Mineralogy: Cassiterite ( 4 -5) __ Magnetite (3 -5) __ Ilmenite (2 -5) __ Zircon (2 -5) __ 

Monazite (3 -5) __ Allanite (2 -5) __ 

GeochemicalSignature: Sn (4 -5) __ As (2 -5) __ B (3 -5)_ F (3 -5} __ W (3 -4) __ Zn (2 -5} __ 

Be (2 -5)_ Zr (1 -1)_ Nb (1 -3)_ Ta (1 -3)_ 

GeophysicalS ignature: 

AssociatedDeposits: Alluvial-placer-Sn __ 

MaxScore: 925 

Partial Scores 

AgeRange: __ RockTypes: __ TextureStructure: __ Alteration: __ 

Mineralogy: __ GeochemicalSignature: __ GeophysicalSignature: __ 

AssociatedDeposits: __ 

Model39e 

167 
Appendix E. Minerals identified in solution-collapse breccia pipe uranium deposits 

[Primary ore and gangue minerals marked by *; others oxidized or supergene (modified after Wenrich and Sutphin, 1988, table 1 )] 

A. ORE MINERALS B. BASE-METALMINERALS 

URANIUM 

uraninite* 

coffinite 

tyuyamunite 

metatyuyamunite 

metazippeite 

zeunerite 

me tazeunerite 

metatorbemite 

uranophane 

bayleyite 

uranospinite 

VANADIUM 

hewettite 

vesigneite 

volborthite 

calciovolborthite 

roscoelite* 

SILVER 

acanthite 

naumannite 

proustite 

GOLD 

Native(?) 

168 

COPPER 

chalcocite 

djurleite 

digenite 

covellite 

enargite* 

chalcopyrite* 

lautite* 

bornite 

tennantite* 

tetrahedrite* 

cuprite 

tenorite 

chrysocolla 

azurite 

malachite 

olivenite 

chalcanthite 

brochantite 

cyanotrichite 

chalcoalumite 

langite 

antlerite 

devilline 

conichalcite 

LEAD 

galena* 

anglesite 

cerussite 

wulfenite 

ZINC 

adamite 

sphalerite* 

smithsonite 

aurichalcite 

hemimorphite 

COBALT 

skutterudite* 

Co-gersdorffite * 

erythrite 

linnaeite* 

bieberite 

NICKEL 

nickeline* 

rammelsbergite* 

pararammelsbergite* 

gersdorffite* 

bravoite* 

siegenite* 

vaesite* 

millerite* 

C. NON-METALLIC MINERALS 

quartz* 

chalcedony* 

pyrobitumen* 

celadonite 

illite 

kaolinite* 

chlorite 

fluorite* 

calcite* 

barite* 

dolomite* 

ankerite* 

anhydrite* 

gypsum 

hexahydrite 

leonhardtite 

MOLYBDENUM 

molybdenite* 

ilsemannite 

jordisite 

IRON 

pyrite* 

marcasite* 

arsenopyrite* 

siderite* 

scorodite 

melanterite 

limonite 

hematite 

goethite 

jarosite 

siderotil 

coquimbite 

MANGANESE 

rhodochrosite 

ANTIMONY 

stibnite* 

~ 


~') 

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