Chemical Data for Flows and 

Feeder Dikes of the Yakima Basalt Subgroup, 

Columbia River Basalt Group, 

Washington, Oregon, and Idaho, 

and their Bearing on a Petrogenetic Model 
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Chemical Data for Flows and 

Feeder Dikes of the Yakima Basalt Subgroup, 

Columbia River Basalt Group, 

Washington, Oregon, and Idaho, 

and their Bearing on a Petrogenetic Model 

By THOMAS L. WRIGHT, MARGARET MANGAN, and 

DONALD A. SWANSON 

U.S. GEOLOGICAL SURVEY BULLETIN 1821 
DEPARTMENT OF THE INTERIOR 

DONALD PAUL HODEL, Secretary 

U.S. GEOLOGICAL SURVEY 

Dallas L. Peck, Director 

Any use of trade, product, industry, 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 : 1989 

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 

Wright, Thomas L. (Thomas Llewellyn), 1935-

Chemical data for flows and feeder dikes of the 

Yakima Basalt Subgroup, Columbia River Basalt Group, 

Washington, Oregon, and Idaho, and their bearing on a 

petrogenetic model. 

(U.S. Geological Survey bulletin ; 1821) 

Bibliography: p. 

Supt. of Docs. no.: I 19.3:1821 

1. Basalt-Northwest, Pacific-Analysis. 2. Petrogenesis--Northwest, Pacific. I. Mangan, Margaret T. 

II. Swanson, Donald A. Ill. Title. IV. Series. 

QE75.B9 no. 1821 557.3 s 89-600010 

[QE462.B3] [552'.26'09795] 
CONTENTS 

Abstract 1 

Introduction 2 

Acknowledgments 2 

Stratigraphic nomenclature and geochemical units 3 

General geologic relations 5 

Vents for flows of the Yakima Basalt Subgroup 6 

Chemical study of the Yakima Basalt Subgroup 6 

Methods of analysis 6 

Presentation of chemical data 8 

Petrography 9 

Classification and naming of chemical types 9 

Bulk rock chemistry: observations 10 

Grande Ronde Basalt 10 

Wanapum Basalt 11 

Saddle Mountains Basalt 11 

Comparison of dike and flow chemistry 12 

Glass chemistry: observations 12 

Discussion: implications for the origin of the Yakima Basalt Subgroup 13 

Emplacement of flows 13 

Magma storage before eruption 13 

Nature of the source mantle 14 

Inferences based on geochemical data 14 

Inferences based on tectonic history 16 

Summary and synthesis: magma generation, storage, and eruption of the Yakima 

Basalt Subgroup 16 

Previous hypotheses 16 

Synthesis 18 

References cited 19 

FIGURES 

l. Index map of Columbia River Plateau 3 

2. Stratigraphy of the Columbia River Basalt Group 5 

3. Location of linear vent systems, Yakima Basalt Subgroup 7 

4. MgO variation diagrams, Yakima Basalt Subgroup 46 

5. Thorium variation diagrams, Yakima Basalt Subgroup 58 

6. Rare-earth-element data (chondrite normalized) for Yakima Basalt Subgroup 66 

7. Isotope data, Yakima Basalt Subgroup 69 

8. MgO variation diagrams, comparing rock and compositions, Yakima Basalt Subgroup glass 70 

9. Patterns of chondrite-normalized abundances of rare-earth elements in additional analyzed 

flows 71 

TABLES 

l. Relation between stratigraphic position and chemistry,Yakima Basalt Subgroup, Columbia River 

Basalt Group 4 

2. Average analytical differences among three laboratories 8 

3. Average chemical composition of geochemical units in the Grande Ronde Basalt 24 

4. Average chemical composition of geochemical units in the Wanapum Basalt 30 

5. Average chemical composition of geochemical units in the Saddle Mountains Basalt 31 

6. Average chemical composition of feeder dikes in the Yakima Basalt Subgroup 34 

7. Ratios of incompatible trace elements in samples of the Grande Ronde Basalt 35 

Contents Ill 
8. Ratios of incompatible trace elements in samples of Wanapum Basalt 36 

9. Ratios of incompatible trace elements in samples of Saddle Mountains Basalt 37 

10. Corrected and normalized major-oxide chemistry of naturally quenched glass from the Grande 

Ronde Basalt 38 

11. Corrected and normalized major-oxide chemistry of naturally quenched glass from the Wanapum 

Basalt 38 

12. Corrected and normalized major-oxide chemistry of naturally quenched glass from the Saddle 

Mountains Basalt 38 

13. Summary of chemical characteristics for geochemical units in the Yakima Basalt Subgroup 39 

14. Relation between stratigraphic position, chemistry, and additional flows, for which chemical data 

are available, Columbia River Plateau 41 

15. Average chemical composition of additional analyzed flows of table 14 42 

16. Ratios of incompatible trace elements in additional analyzed flows of table 14 44 

17. Summary of chemical characteristics of additional flows for which chemical data are available, 

Columbia River Plateau 45 

IV Contents 
Chemical Data for Flows and 

Feeder Dikes of the Yakima Basalt Subgroup, 

Columbia River Basalt Group, 

Washington, Oregon, and Idaho, 

and their Bearing on a Petrogenetic Model 

By Thomas L. Wright, Margaret Mangan, and Donald A. Swanson 

Abstract 

Regional geologic mapping of the Yakima Basalt Subgroup of the Columbia River Basalt Group provides for a 

threefold division of the subgroup-from oldest to youngest, 

the Grande Ronde Basalt, Wanapum Basalt, and Saddle 

Mountains Basalt. Systems of feeder dikes and vents trending 

north to north-northwest have been identified for most units. 

Regional flow correlations, made on the basis of geologic 

mapping, major-oxide chemistry, and magnetic polarity, 

show that many flows have volumes of more than 500 km3 , 

traveled hundreds of kilometers from their vents, and had 

emplacement times of a few days to a few weeks. 

Samples of the subgroup were extensively analyzed for 

major oxides, trace elements, and isotopes of Sr, ENd, Pb, and 

0. Chemical analyses allow recognition of geochemical 

units consisting of a flow or several related flows of nearuniform composition, some of which represent chemical 

types repeated throughout the section. Average compositions 

of geochemical units have been plotted and are used in 

drawing petrogenetic inferences. All regionally extensive 

flows are tholeiitic and have MgO contents in the range of 

2.5-8.0 percent. Each formation is characterized by specific 

chemical compositions. Flows of the Grande Ronde Basalt 

are aphyric and have low MgO (3-6 percent}, high SiO 

(52-58 percent), and relatively low Ti02 (1.5-2.5 percent) 

and FeO (9-13 percent} contents and a relatively low initial 87Sr/86Sr isotopic ratio (0.703-0.705). Most flows of the 

Wanapum Basalt have lower Si02 (49-52 percent} for the 

same range of MgO, much higher contents of TiO (>3 percent) and FeO (13-15 percent), and somewhat higl,er initial 87Srf86

Sr (0.704--0.7055). Trace elements are similar overall 

in both formations despite the contrasts in major-oxide chemistry. Chondrite-normalized rare-earth patterns for both formations show enrichment in light rare earths, are slightly 

concave upward with small or no negative europium anomalies, and at differing degrees of absolute rare-earth content are 

parallel to slightly convergent toward the heavy rare earths. 

The Saddle Mountains Basalt contains members spanning a wide range of major-oxide composition, including 

some whose major-oxide compositions match those of older 

units. With few exceptions, incompatible trace elements are 

enriched and compatible elements (particularly Sr and Sc) 

depleted relative to older formations, and values of the 87Sr/ 86Sr ratio are higher (>0.707). Chondrite-normalized rareearth patterns for many of the ten members of the Saddle 

Mountains Basalt are steeper and show a more pronounced 

negative europium anomaly than those of the older formations. However, one member (the Umatilla Member) has a 

pronounced positive europium anomaly. 

Trace-element variation, represented by interelement 

ratios or absolute abundances plotted against MgO content, is 

less coherent in the Yakima Basalt Subgroup than in oceanic 

basalts. Some major-oxide compositional trends suggest that 

crystal-liquid fractionation occurred, but several other lines of 

evidence, both geologic and geochemical, argue against lowpressure crustal storage and fractionation. This evidence 

includes the divergence of chemical trends for coexisting 

rock and glass from those relating one bulk rock composition 

to another, inconsistent incompatible trace-element enrichments, and the absence of major structural depressions such 

as grabens and calderas that should be associated with the 

virtually instantaneous eruption of the huge volumes represented by individual units. Major- and trace-element variation 

likewise is difficult to reconcile with any simple model of 

high-pressure fractionation, melting from a common source, 

or mixing of magma with crustal material, although some 

combination of these processes may have been important for 

some units. 

Interpretation of the petrogenesis of the Yakima Basalt 

Subgroup requires consideration of such diverse topics as the 

tectonic history of the Pacific Northwest, generalized models 

of flood-basalt genesis, and the process of continental crustal 

underplating, in addition to the chemical and isotopic data. 

Recent geophysical studies and deep drill holes show that the 

Columbia River Basalt Group is underlain by upper Mesozoic 

and lower Cenozoic sedimentary rocks that define a large 

preexisting sedimentary basin. This depression may have 

been created as a back-arc basin when the older continental 

margin and associated subduction zone moved westward 

away from a once-continuous belt of plutonic rocks represented in the Pacific Northwest by the Idaho batholith. We 

postulate that large volumes of magma were generated in a 

mixed oceanic-continental source mantle and were emplaced 

Abstract 
as sill-like bodies at the base of the continental crust. These 

bodies were then progressively tapped during deep continental rifting and supplied magma to the surface via extensive 

linear vent systems. All of the magma is inferred to have 

equilibrated with clinopyroxene during either melting or 

storage. Recent experimental study of the Grande Ronde 

Bas~lt at p~essures to 3 GPa suggests an origin by direct 

part1al meltmg of a source related to mid-ocean ridge basalt 

and its source mantle, possibly at a depth of 70 km. 

The earliest basalt of regional extent, the Grande Ronde 

Basalt, began to fill the basin with lava derived from fairly 

young oceanic crust and mantle contaminated with subdueled oceanic sediment. Such magma was then repeatedly 

er~pte~ after . stora~e near the crust-mantle boundary and 

mmor mteract1on w1th lower-crustal rocks during ascent. The 

Wanapum Basalt formed in much the same way, although 

from a part of the oceanic mantle that had undergone Fe-Tip metasomatism. The similarity of the major-oxide chemistry 

of the Saddle Mountains Basalt to that of older units suggests 

a source related in some way to that of the Grande Ronde 

and Wanapum Basalts. However, the different trace-element 

abu~dances and ratios require additional complexity, such as 

~eltmg ~f a 2.5-Ga continental mantle having rather high 

1ncompat1ble element contents or melting of mantle that had 

undergone a second metasomatic event. 

Eruption rates generally kept pace with continued 

basining during formation of the Yakima Basalt Subgroup. At 

times, the basin became filled and large-volume flows continued through the ancient Columbia River Gorge to the Pacific 

Ocean. At other times, continued subsidence of the central 

plateau, possibly combined with uplift of the eastern margin 

of the plateau, created a gentle westward-dipping slope. 

Volcanism waned around 14 Ma and finally stopped at about 

6 Ma, though the weight of the basalt pile caused continued 

subsidence as isostatic equilibrium was reestablished. 

INTRODUCTION 

The Columbia River Basalt Group forms the youngest 

known flood-basalt province; eruptions occurred over an 

11-m.y. period (17-6 Ma) in the early to late Miocene 

(Watkins and Baksi, 1974; McKee and others, 1977, 1981; 

Hooper, 1982, fig. 2; Swanson and others, 1979a). The 

group contains more than 170,000 km3 of tholeiitic basalt 

and covers an area of 160,000 km2 to a maximum depth of 

at least 3 km, as inferred from surface exposures (fig. 1; 

Tolan and others, 1987), drill-hole data (Lingley and 

Walsh, 1986), and geophysical surveys (Stanley, 1984; 

Glover and others, 1985). The basalt is underlain by sedimentary rocks 4-5 km thick (Stanley, 1984; Glover and 

others, 1985), which in turn overlie crystalline basement 

that extends to the base of the crust, estimated to be 40 km 

deep (Catchings and others, 1984). Mapping of the province is complete; regional map compilations are by Swanson and others (1979b, 1980, 1981), Anderson and others 

(in press), and Hooper and Swanson (in press) and references therein. Wright and others (1973) summarized 

major-oxide chemistry of important units and used those 

data to define several chemical types. Trace-element data 

for selected units were published by Nathan and Fruchter 

(1974) and by the NASA-sponsored Basaltic Volcanism 

Study Project (1981). Subsequently, we have defined 

additional chemical types and analyzed trace elements for 

all chemical types defined by major oxides. Many of these 

data are contained in open-file reports (Wright and others, 

1979, 1980, 1982); a summary is given by Swanson and 

Wright (1981). Isotopic data for Sr, eNd, Pb, and 0 are 

summarized by McDougall (1976), Nelson (1980; 1983), 

Carlson and others (1981), Carlson (1984a), and Church 

(1985). 

The purposes of this paper are (1) to summarize the 

chemical composition of all units of the Yakima Basalt 

Subgroup (table 1) mapped by two of us (DAS and TLW) 

in Washington and northeastern Oregon and (2) to evaluate 

implications for the origin of the Yakima Basalt Subgroup 

from available geologic, petrographic, geochemical, and 

geophysical data. A definitive petrogenesis awaits quantitative modeling of chemical data using the results of experimental study of representative flow compositions. 

Such studies are currently underway by Eiichi Takahashi, 

and preliminary results are available (Takahashi, 1988). 

Ultimately, any quantitative petrogenetic model of the 

complex processes that gave rise to the basalt must be 

based on significantly improved understanding of the nature of the upper mantle and lower crust; such an understanding probably remains far in the future. 

The descriptive sections of the main body of this paper 

give (1) summary tabulations and graphical representations 

of the major-oxide, trace-element, and isotope chemistry of 

the flows; (2) chemistry of feeder-dike systems for many 

units; and (3) a comparison of major-oxide chemistry of 

regionally extensive flows with that of glass selvedges from 

associated dikes or pillows. Discussion sections specify the 

critical observations that delimit possible conditions of 

magma generation, storage, and eruption and summarize 

the tectonic and magmatic evolution of the Yakima Basalt 

Subgroup. Tables 14-17 summarize chemical data for 

additional flows collected by us that either have been 

mapped in more detail by other workers or are interlayered 

with, but not considered by other workers to be a part of, 

the Columbia River Basalt Group. These flows include 

local flows in the Clearwater embayment of Idaho mapped 

by Camp ( 1981) and local flows in northeastern Oregon 

mapped by P.R. Hooper and W.T. Taubeneck (unpublished 

work). Both groups of flows are of Saddle Mountains age 

(table 14). With one exception, flows of the former group 

are considered to belong to the Yakima Basalt Subgroup. 

Flows of the latter group are, again with one exception, 

mapped separately by Hooper (1984) as the basalts of 

Powder River, which he excludes from the Columbia River 

Basalt Group. 

Acknowledgments 

This paper is the product of a decade of work on the 

Columbia River Plateau. We acknowledge the Department 

of Energy and personnel of Rockwell International for 

2 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
providing part of the funding to support this research. Peter 

Hooper supplied many analyses through his laboratory at 

Washington State University; Brent Fabbi and Floyd 

Brown worked closely with the authors in providing a 

consistent body of data from U.S. Geological Survey laboratories. Kevin Black did a superb job in setting up and 

maintaining a complete data base for analytical data and 

sample locations. We appreciate comments on an early 

version of the manuscript made by P.R. Hooper, S. Reidel, 

K. Cox, and R. Wells, and we acknowledge Rick Carlson 

for many discussions of the petrogenetic interpretations 

based on his isotopic data. Eiichi Takahashi has shared the 

results of his ongoing experimental study and its implications for petrogenesis of the Columbia River Basalt Group. 

The present manuscript has benefited from thorough and 

incisive reviews by John Pallister and Rosalind Helz. 

STRATIGRAPHIC NOMENCLATURE AND 

GEOCHEMICAL UNITS 

Swanson and others (1979a; table 1 and fig. 2) worked 

out a revised stratigraphy for the Columbia River Basalt 

Group (fig. 2). The Grande Ronde Basalt has no formally 

named members but is divided for purposes of mapping 

into four magnetostratigraphic units: from oldest to youngest, Rl' Nl' R2

, and N2• The Wanapum Basalt has four 

formally named members: from oldest to youngest, the 

Eckler Mountain, Frenchman Springs, Roza, and Priest 

117" 

CANADA 

------------------------ --r----~-----

1 I 

WASHINGTON i i I I 

z 

<( 

L.l.l 

u 

0 

0 

IJ.J 

Q 

C5 

C/) 

C5 

100 KILOMETERS 

i i 

\ 

' \ 

OREGON • Boise 

Figure 1. Index map of Columbia River Plateau. Outline of area covered by Columbia River Basalt Group (shaded) is modified 

from that given in Swanson and others (1979a) to include results of recent mapping west of Cascade Range (see Tolan and 

others, 1984, fig. 2). Compilation of mapping east of Cascade Range has resulted in slight modification of rest of boundary 

but not to an extent to affect material presented in this paper. 

Stratigraphic Nomenclature and Geochemical Units 3 
Table 1. Relation between stratigraphic position and chemistry, Yakima Subgroup, Columbia River Basalt Group 

[MP, magnetic polarity as determined in the field using a fluxgate magnetometer; N, normal; R, reversed; 

T, transitional. Magnetic polarity units after Swanson and others (197 9a) . Geochemical units of the Grande Ronde Bas a 1 t 

are defined in Mangan and others (1985). Units marked with an asterisk (*) are defined from sections located in the 

western plateau] 

Formation 

Member 

Flow Age MP Geochemical 

(Informal N arne) (Ma) unit 

SADDLE MOUNTAINS BASALT 

Lower Monumental 

Ice Harbor 

Basalt of Goose Island 

Basalt of Martindale 

Indian Memorial flow 

Martindale flow 

Basalt of Basin City 

Buford 

6 

8.5 

Elephant Mountain 10.5 

Wenaha flow (Walker, 1973) 

Pomona 12.0 

Basalt of Weippe (Camp, 1981) 

Esquatzel 

Weissenfels Ridge 

Basalt of Slippery Creek 

Basalt of Lewiston Orchards 

Sprague Lake flow 

Anatone flow (Price, 1974) 

Asotin 

Huntzinger flow (Ward, 1976) 

Basalt of Lapwai 

Eagle Lake flow 

Wilbur Creek 

Umatilla 

Umatilla flow 

Sopher Ridge flow 

W ANAPUM BASALT 

Priest Rapids 

Powatka flow 

Roza 

Frenchman Springs 

Eckler Mountain 

Basalt of Shumaker Creek 

Lookingglass flow 

Basalt of Dodge 

Basalt of Robinette Mountain 

N 

N 

N 

R 

N 

N 

LM 

GOOSE 

INDIAN 

MARTIN 

BASIN 

BUFORD 

N,T ELEPHANT 

R POMONA 

R VC WEIPE 

N ESQUAT 

N RBESQUAT 

R FS IC 

N SLIP 

N LEWORCH 

SPRAGUE 

SWSPRAG 

NEW 

SWNEW 

N ASOTIN 

VCASOT 

N SWHUNTZ 

HUNTZ 

N VC LAP 

N EAGLE 

N WILBUR 

N UMATILLA 

UMFRAC 

PH UMTIL 

PH SOPHER 

R PV 

LOLOINC 

ROSALIA 

T,R PH POWAT 

N2 ROZA 

N2 FS ANOM 

N2 

FS INC 

SHUMAKER 

PHSHUM 

SWLOOK 

DODGE 

ROBIN 

Formation--Continued 

Magnetostratigraphic unit 

Age MP Geochemical 

(Ma) unit 

GRANDE RONDE BASALT 16.5 -14.4 

N 

Magnetostratigraphic unit N2 N 

Magnetostratigraphic unit N2 

Magnetostratigraphic unit R2 

Magnetostratigraphic unit R2 

Magnetostratigraphic unit Nl 

Magnetostratigraphic unit N1 

Magnetostratigraphic unit R 1 

IMNAHA (C-3) 

N 

T 

T 

R 

R 

T 

N 

N 

R 

17-16 R 

JOSEPH1 

GRINC 

1A 

1A* 

2A 

UNC 

3A 

3A* 

UNC 

4A 

4A* 

UNC* 

3B 

UNC 

4B 

LH2 

MG6 

2B 

5A 

5A* 

UNC 

2C 

4C 

5B 

3C 

3C* 

UNC 

5C 

5C* 

3D 

5D 

5D* 

UNC 

2D 

2D* 

UNC 

ASI6 

2E 

UNC 

KB5 

3E 

UNC 

3F 

5E 

ASI6 

3G 

5F 

UNC 

ASI6 

5G 

ASI6 

5H 

AS16 

UNC 

AS16 

2F 

51 

ASI6 

1 The Joseph volcanics unit of Klecl< (1976) is composed of a series of glassy shield volcanoes sitting on top of the Grande Ronde Basalt 

in northeastern Oregon. Their chemistry suggests affinity with the Grande Ronde Basalt. 

4 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Croup, Washington, Oregon, and Idaho 
Rapids Members. Beeson and others (1985) have shown 

that there is no interbedding between these two formations, 

though such had been inferred by Swanson and others 

(1979a). Neither set of authors found evidence of a 

magnetic polarity reversal between Grande Ronde and 

Wanapum times. Accordingly, we believe that the Eckler 

Mountain and Frenchman Springs Members of the Wanapum Basalt fall in magnetostratigraphic unit N2

, as does 

the upper part of the Grande Ronde Basalt; the Roza 

Member is transitional from unit N2 into unit R3

. and the 

Priest Rapids Member lies within unit R3

• The Saddle 

Mountains Basalt is divided into ten members (fig. 2), all 

of which are separated by erosional unconformities. The 

magnetostratigraphy is probably discontinuous; thus the 

polarity of each unit is designated in table 1 as N or R 

without a subscript. 

Each member of the formations of the Yakima Basalt 

Subgroup (fig. 2) is composed of several flows, or sequences of flows, each of which has a distinctive majoroxide composition. The average chemistry of each flow 

sequence defines a geochemical unit of a certain chemical 

type1

, which is given an abbreviation related to its stratigraphic position (table 1). Some of the names of such units 

relate to locally mappable units defined since 1979 (see 

columns headed "flow" and "informal name" in table 1). 

Regional correlation of flows is based on geologic mapping, flow chemistry, and paleomagnetic measurements 

(compare Choiniere and Swanson, 1979; Hooper, 1981; 

Mangan and others, 1986). The stratigraphic nomenclature, 

chemical designation, radiometric age, and magnetic polarity of each unit in the Yakima Basalt Subgroup are given 

in table 1. 

GENERAL GEOLOGIC RELATIONS 

The regional distribution of formations and members in 

the Yakima Basalt Subgroup was originally given by 

Swanson and others (1979a, plate 1); distribution maps for 

individual members have been updated by Anderson and 

others (in press), and the volumes of the formations that 

make up the Yakima Basalt Subgroup have been newly 

estimated by Tolan and others (1987). Flows of the Grande 

Ronde Basalt cover most of the Columbia Plateau. Products of individual eruptions range from plateau-covering 

basaltic floods to smaller flows of more local distribution 

(Mangan and others, 1985, 1986). Flow contacts in the 

Grande Ronde are generally tight; a few thin and discontinuous intercalations of sedimentary and tuffaceous depos-

'The term "geochemical unit" as used in this paper is similar to but not identical to 

the term "chemical type" used previously. The former term carries with it a specific 

stratigraphic as well as chemical meaning. The Grande Ronde Basalt is the only unit where 

chemical types. originally defmed for one stratigraphically bound set of flows of similar 

chemistry arc repeated throughout the stratigraphic section and thus arc properly referred 

to as "chemical types," retaining the chemical defmition while dropping the stratigraphic 

meaning; sec, for example Mangan and others (1986). 

its occur, principally near the margins of the Plateau. The 

regional extent of the Wanapum Basalt is nearly as great as 

that of the Grande Ronde Basalt. Both formations contain 

flows or sequences of flows with volumes in excess of 500 

km3; examples include the Roza Member, the Priest Rapids 

Member (LOLO geochemical unit); Grande Ronde Basalt, 

unit 4a*. Maximum thicknesses where flows were ponded 

are nearly 100 m, as estimated from surface exposures and 

drill holes. 

A saprolite separates the Grande Ronde and W anapum 

Basalts in the central part of the Columbia Plateau. The 

saprolite thickens toward the margins of the Plateau, where 

it may underlie or be replaced by sedimentary deposits (the 

Vantage Member of the Ellensburg Formation in the westem Plateau and the Latah Formation in the eastern Plateau). 

The time interval during which the Grande Ronde Basalt 

was weathered was apparent! y not great, for no evidence 

Group Subgroup Formation Member 

Lower Monumental Member 

rn Ice Harbor Member Q Buford Member ·ca Elephant Mountain Member ...... ...... oca Pomona Member ::l rn o ro Esquatzel Member 

::gm Weissenfels Ridge Member Q.) 

:0 Asotin Member 

0. "'0 Wilbur Creek Member 

;::l ro Umatilla Member 0 rJ) 

1-t 

'OJJ 

"§ -+-1 (/) 

-+-1 ~ Priest Rapids Member (/) 

0. ~ ro Roza Member ;::l (/) o:l Frenchman Springs Member 8 ro 

o:l s Eckler Mountain Member ~ ro ;::l -+-1 s 0. ~ ro (/) 

~ ~ ro 

o:l 

1-t 

~ ~ Q) 

~ -+-1 

ro ~ 

~ (/) 

ro No members defined 

o:l (see table 1 for 

~ -+-1 

~ Q) paleomagnetic and "0 

u (/) ~ chemical subdivision) ro 

o:l & Q) Q) 

~ "0 

0 

~ § 1-t 

Q) ~ 

;::l 

-+-1 

u 

0:: 

ro ..... .r::~ No members defined ro oo ~ro .§m 

Figure 2. Stratigraphy of the Columbia River Basalt Group, 

after Swanson and others (1 979a). 

General Geologic Relations 5 
for a polarity reversal has been recognized between Grande 

Ronde and W anapum times. 

The Saddle Mountains Basalt began to be erupted after 

an interval of erosion lasting perhaps as long as one million 

years. Saddle Mountains time extends from approximately 

13 to 6 Ma, and significant time breaks separate the eruptions of each member of the Saddle Mountains (table 1). 

Many flows of the Saddle Mountains Basalt are preserved 

as remnants of valley-filling flows on the walls of presentday canyons and must originally have flowed down deep 

canyons cut into the Grande Ronde and Wanapum Basalts 

in the eastern part of the Plateau (Swanson and others, 

1975a). Some individual flows are as voluminous as those 

in the Wanapum and Grande Ronde Basalts, and many 

traveled as far or farther because of channeling in river 

valleys. However, the Saddle Mountains Basalt covered 

less of the Plateau surface than did the earlier units. 

VENTS FOR FLOWS OF THE 

YAKIMA BASALT SUBGROUP 

All flows were erupted from fissures and fed by dikes. 

Several outcrops are known in which a dike merges into the 

flow it fed (Swanson and others, 1975b). The location of a 

dike thus defines the trace of a vent fissure. Only rarely are 

the surface expressions of vents, such as cones and spatter 

ramparts, preserved (Bingham, 1970; Swanson and others, 

1975b). 

Dikes and vents for flows of each stratigraphically 

bound geochemical unit define one or more narrow linear 

vent systems (Swanson and others, 1975b), as long as 150 

km, many of which are composed of echelon segments. 

Most or all vent systems trend NNW. (azimuth 310°-350°) 

and are located in central and eastern Washington, northeastern Oregon, and western Idaho (fig. 3), with most 

known dikes occurring in extreme southeastern Washington 

and northeastern Oregon (Taubeneck, 1970, 1978). Each 

linear vent system is near the eastern margin of the flows 

it fed, consistent with other indications that a gentle westward slope was formed and persisted during the time of 

eruption of the Yakima Basalt Subgroup. Maps showing 

the location of linear vent systems and the known extent of 

flows they fed are given in Swanson and others (1979a, 

plate I) and in Anderson and others (1987). Locations and 

chemical analyses of individual dikes are given by Wright 

and others (1979, 1980). Locations of additional dikes and 

vents in Idaho are given by Camp (1981) and Swanson and 

others (1981). 

Within the overall dike system (fig. 3) no regular progression of vent location through time has been recognized 

for the subgroup. Linear vent systems for the Grande 

Ronde Basalt occur throughout the entire area of the dike 

swarm. Linear vent systems for each member in the 

Wanapum Basalt occupy distinct regions, and there was an 

eastward migration of vents for the upper members of the 

Wanapum: those for the Frenchman Springs Member are 

near the western margin of the dike swarm, those for the 

Roza are in eastern Washington, and those for the Priest 

Rapids are in Idaho within the eastern part of the dike 

swarm. Sources for the Saddle Mountains Basalt are scattered across the entire area, from central Washington (Ice 

Harbor Member) through eastern Washington and Oregon 

(Elephant Mountain and Umatilla Members) to Idaho 

(Weissenfels Ridge Member), and show no systematic 

variation of vent location with time. 

The following members of the Saddle Mountains 

Basalt have no identified source vents or dikes: Lower 

Monumental, Pomona, Esquatzel, Weissenfels Ridge (basalt of Slippery Creek), Asotin, and Wilbur Creek Members. Until recently, the basalt of Weippe (Camp, 1981) 

and its feeder dike were considered correlative with the 

Pomona Member. However, the paleomagnetic and isotopic signatures of the Weippe dike have been shown to 

differ from those of the mapped Pomona Member, although 

the major-oxide and trace-element chemistry are identical 

(P.R. Hooper, oral commun., 1986). In addition, no vent is 

known for the Lookingglass flow in the Eckler Mountain 

Member of the Wanapum Basalt. Four of these units traveled to or across the central area of the Columbia Plateau, 

and three of these (Pomona, Asotin, and Wilbur Creek 

Members) each have volumes that exceed 40 km3• We 

made a careful search along the eastern margin of the 

outcrop area, after completion of the regional mapping, for 

dikes or vents that could have fed these units, but we found 

none. Therefore we conclude that the sources for these 

units are not presently exposed. 

CHEMICAL STUDY OF THE 

YAKIMA BASALT SUBGROUP 

Methods of Analysis 

Major oxides were analyzed in the laboratories of the 

U.S. Geological Survey (USGS) in Reston, Virginia, 

(Rapid Rock) and Menlo Park, California, (X-ray fluorescence) and in the X-ray fluorescence laboratory at Washington State University (WSU) under the direction of P.R. 

Hooper (see Hooper, 1981). Electron microprobe analyses 

of natural sideromelane glass were obtained at the Smithsonian Institution in Washington, D.C. Trace-element 

determinations have been made by instrumental neutron 

activation analysis (INAA) for Ba, Co, Cr, Cs, Hf, Rb, Th, 

U, Zn, Zr, Sc, and the rare-earth elements La, Ce, Nd, Sm, 

Eu, Gd, Tb, Yb, and Lu; by X-ray fluorescence (XRF) for 

Ba, Rb, Sr, Zr, Nb, andY; and by atomic absorption spectroscopy (AAS) for Cu and Ni. Ba, Rb, and Zr were therefore determined by both XRF and INAA. Analyses and 

methods used for major oxides and for trace-element data 

obtained by INAA are given by Wright and others (1979, 

1980, 1982). 

6 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
Analyses of trace elements by XRF were obtained from 

the USGS laboratory in Reston under the direction of Harry 

Rose; the analyst was Bob Johnson. Analyses by AAS 

were done by Jean Kane, also in the USGS laboratories in 

Reston. 

120° 47°==~~~~~~,~~~~~~~~~~~~---~~ 

The analytical errors of the various data, though difficult to estimate, are much less than the differences between 

defined geochemical units and therefore do not affect the 

discrimination of one such unit from another. Relative 

values for trace elements analyzed by two methods are in 

0 50 KILOMETERS I I I I 

EXPLANATION 

DIKES ASSOCIATED WITH STRATIGRAPHIC UNITS 

(GEOCHEMICAL UNITS IN PARENTHESES) 

X Grande Ronde Basalt 

Wanapum Basalt 

P Priest Rapids Member (LOLO. ROSALIA, PV) 

R Roza Member 

F Frenchman Springs Member (FS INC, FS ANOM) 

Eckler Mountain Member 

S (SHUMAKER) 

0 (DODGE) 

* (ROBIN) 

Saddle Mountains Basalt 

Ice Harbor Member (GOOSE, MARTIN, INDIAN, BASIN) 

8 Buford Member 

E Elephant Mountain Member 

W Weissenfels Ridge Member (SPRAGUE, NEW, LEW ORCH) 

U Umatilla Member 

* Unclassified 

Figure 3. Location of linear vent systems for the Yakima Basalt Subgroup of the Columbia River Basalt Group. Area of 

Columbia River Basalt Group shaded. See table 1 for stratigraphic setting of units. A, Grande Ronde Basalt. B, Wanapum 

Basalt. C, Saddle Mountains Basalt. 

Chemical Study of the Yakima Basalt Subgroup 7 
Table 2. Average analytical differences among three 

laboratories 

[XRF, U.S. Geological Survey, Menlo Park, X-ray 

fluorescence analyses; WSU, Washington State 

University, X-ray fluorescence analyses. Biases 

obtained by subtracting values obtained by 

reference laboratory, U.S. Geological Survey, 

Reston, rapid rock analyses. Biases calculated 

from analyses of selected samples done by at least 

two different laboratories, and from comparison of 

flow averages for major stratigraphic units 

calculated from analyses obtained from each 

laboratory in course of regional mapping. Biases 

vary somewhat as a function of bulk chemistry, 

although signs, + or -, are consistent. Analyses 

in tables in this paper have not been corrected] 

Oxide Bias (XRF) Bias (WSU) 

Si02 -0.74 +0.33 

Alz03 0.00 -0.48 

'FeO' +0.35 -0.30 

MgO +0.01 +0.16 

CaO -0.08 -0.17 

K20 +0.07 0.00 

Ti02 +0.04 +0.02 

PzOs +0.09 +0.05 

MnO n.a. n.a. 

good agreement, although the precision and accuracy are 

probably greater for the XRF than for the INAA analyses. 

We have not specifically studied the chemical variation 

within single flows. An empirical measure of the variability 

within a geochemical unit is obtained from the variation 

shown by regional sampling of the same flow or stratigraphic unit, and this variability has been used to scale the 

plots (see below). Major-oxide analyses made in different 

laboratories show systematic differences (table 2), and only 

analyses from the USGS laboratories are used to discuss 

chemical differences and their interpretation. This is done 

for consistency and does not imply that these analyses are 

better than those from other laboratories. 

Presentation of Chemical Data 

The chemical data on which the discussions and inferences in this paper are based are given in tabular form. 

Average whole-rock and glass compositions and trace-element ratios of geochemical units and whole-rock compositions of feeder dikes appear together with the main text 

(tables 3-12); chemical data on some additional analyzed 

flows (see table 14) are given in the appendix (tables 

15-17); and the individual analyses from which the average 

compositions were derived are published separately as a 

U.S. Geological Survey Open-File Report (Wright, 1988). 

The average major- and trace-element compositions of 

flows defining each geochemical unit are listed in stratigraphic order in tables 3-5. Each average represents at least 

two analyses. Data for samples used to compute the averages, including the range and standard deviation for each 

element, are summarized for the Grande Ronde Basalt in 

Mangan and others ( 1985) and for the Wanapum and 

Saddle Mountains Basalts in Wright (1988). The compositions of dikes for geochemical units that have well-defined linear vent systems are given in table 6; individual 

analyses are listed in Wright (1988). The averages calculated from WSU analyses are preceded by a two-letter 

abbreviation related to the original collectors of the sample: 

PH, Peter Hooper; VC, Victor Camp; WT, William 

Taubeneck; RB, Robert Bentley; SW, D.A. Swanson and 

T.L. Wright Abbreviations for geochemical units are 

denoted similarly: SHUMAKER = USGS average, PH 

SHUM = WSU average for samples of the basalt of Shumaker Creek in table 1. Selected trace-element ratios for 

all formations are summarized in tables 7-9. 

Selected data for all units of the Yakima Basalt Subgroup are also plotted in figures 4-6. Data are plotted by 

formation, with the Saddle Mountains Basalt divided into 

two sets of plots, one for flows whose major-oxide chemistry broadly resembles that of the Grande Ronde Basalt 

(relatively high Si02, low total iron as FeO, and low TiOJ, 

the other for flows whose major-oxide chemistry broadly 

resembles that of the upper part of the W anapum Basalt 

(relatively low Si02, high total iron as FeO, and high Ti02

). 

Letter symbols given in tables 4 and 5 are related to stratigraphic position within the Saddle Mountains and Wanapum Basalts from top (A) toward bottom (Z). In the data 

for the Grande Ronde Basalt (table 3), symbols A-E refer 

to major geochemical units repeated throughout the section, 

1 and 2 refer to two distinctively magnesian units of local 

extent, and X represents the remaining Grande Ronde flows 

(Mangan and others, 1985; 1986). An asterisk (*) in the 

name for a geochemical unit (for example, 1A *) is used to 

distinguish averages for units defined in the western plateau; the name used for the same unit in the east~m plateau 

has no asterisk (for example, 1A). The chemical data are 

plotted as follows: 

MgO variation diagrams (fig. 4).-The chemistry of 

each unit is summarized on three plots showing, respectively, major oxides and compatible trace elements, incompatible trace elements, and selected trace-element ratios. 

Th (Thorium) variation diagrams (fig. 5).-The same 

data (including MgO) are plotted against a well-determined 

incompatible element. 

Chondrite-normalized rrareearth-element (REE) data 

(fig. 6).-Symbols differ from those used in tables 3-5 

because of the plotting program used. The plots in figure 

6 show only La, Ce, Sm, Eu, Tb, Yb, and Lu. 

Isotope data (fig. ?).-Previously published data for 

isotopes of eNd, Pb, and 0 are plotted against 87Srj86

Sr. 

Except for plots of trace-element ratios, figures 4 and 5 

are scaled so that the symbol size represents approximately 

two standard deviations in each oxide or element as estimated from statistical analysis of the geochemical units. 

This is necessarily somewhat subjective, as the standard 

8 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
deviation for a given element or oxide varies from one 

geochemical unit to another. Nonetheless they are sufficiently similar to interpret separation of symbols as a petrologically significant chemical difference. Symbol separation does not have the same meaning on plots of MgO or 

Th against element ratios, because of difficulty in estimating quantitatively the errors in the ratios. 

The chemistry of natural glasses is tabulated separately 

(tables 10-12). Data from which the glass averages were 

calculated is given in Wright (1988). The major-oxide 

compositions of bulk rocks and associated quenched 

glasses are compared for selected units in figure 8. 

The chemical characteristics that distinguish each unit 

in the Yakima Basalt Subgroup are summarized in table 13. 

Petrography 

Petrographic data for most units of the Yakima Basalt 

Subgroup have been summarized by Wright and others 

(1973, table 3), although the unit names have been changed 

since (the names 'Upper', 'Middle', and 'Lower' Yakima 

Basalt of previous usage correspond, respectively, to what 

are now defined as the Saddle Mountains, Wanapum, and 

Grande Ronde Basalts). What follows is a brief recapitulation of the previously published data, with petrographic 

information added for units not identified in 1973. 

Grande Ronde Basalt.-Rocks of this unit are mostly 

aphyric or sparsely microphyric with augite-plagioclase 

clots. Many flows have rare microphenocrysts of hypersthene. A few local flows are mappable on the basis of 

visible plagioclase phenocrysts but are not chemically distinctive. 

Wanapum Basalt.-Rocks of this unit are commonly 

sparsely porphyritic with either single (as large as 1 em) 

plagioclase phenocrysts (Roza Member; basalt of Dodge of 

the Eckler Mountain Member), large (1-3 em) plagioclase 

clots (many flows of the Frenchman Springs Member; see 

also Beeson and others, 1985, table 1), or small (1-3 mm) 

olivine and plagioclase phenocrysts (Priest Rapids Member, LOLO geochemical unit). Some flows in the Frenchman Springs Member (see also Beeson and others, 1985) 

and a few flows in the basalt of Dodge are aphyric, as are 

the basalt of Robinette Mountain of the Eckler Mountain 

Member and other W anapum flows not mentioned above. 

The basalt of Dodge is exceptionally coarse-grained (> 1 

mm) and is identifiable in the field, where it commonly 

weathers to a coarse grus. 

Saddle Mountains Basalt.-Flows of the Pomona 

Member and the basalt of Martindale (of the Ice Harbor 

Member) are distiguished by an augite-plagioclase-olivine 

assemblage of phenocrysts and glomerocrysts. The basalt 

of Goose Island (of the Ice Harbor Member) is unique for 

the occurrence of microphenocrysts of ilmenite and titanmagnetite. The Esquatzel Member is distinguished by the 

presence of augite (as large as 5 mm) as the only phenocryst type. The rest of the Saddle Mountains Basalt flows 

are aphyric to sparsely porphyritic, with no phenocrysts 

large enough to be of use in mapping. Flows of the Asotin 

Member have a coarse subophitic texture that is distinctive 

on a eathered surface. 

Class fication and Naming of 

Ceo hemical Units 

Th geochemical units (tables 1 and 3-6) were classified a cording to normative data using procedures recommend by Irvine and Baragar (1971) and by Wilkinson 

( 1986 . The total iron (FeO of tables 3-6) was partitioned 

to Fe 3 and FeO in a ratio of 9: 1 before calculating the 

norm. The Irvine and Baragar procedures yield more 

consi tency in the naming of such units than do the Wilkinson procedures. With one exception, geochemical units 

in the Yakima Basalt Subgroup are classified as subalkaline 

tholei tic basalt using their figure 4 (01'-Ne'-Q'), figure 5 

(Cpx- 1-0px), figure 6 (normative plagioclase An content 

versu Al2

0 3), and figure 7 A (normative plagioclase An 

conte t versus color index). The most fractionated chemistry i the Umatilla Member (UM FRAC geochemical unit 

of tab e 1) was classified as calc-alkaline tholeiitic andesite 

using their figures 6 and 7 A. The single sample of magnesian I naha Basalt (table 15) was also classified as subalkalin tholeiitic basalt on their figures 4, 6, and 7 A, althoug it was barely alkaline using figure 5. Classification 

of th basalts in terms of sodic or potassic affinity using 

their igure 8 (An-Ab'-Or) shows that all the samples of the 

Gran e Ronde and Wanapum Basalts, and the single 

samp e of the Imnaha Basalt, have average K2

0 contents. 

Some members of the Saddle Mountains Basalt (Pomona, 

Esqu tzel, Asotin, Wilbur Creek, and Umatilla Members) 

have omposition ranges that extend slightly into the field 

of K- 'ch basalts. 

e basalts of Powder River (Hooper, 1984), whose 

com sitions are given in table 15, were classified as a 

mix e of subalkaline and alkaline basalt using figures 4 

and 5 of Irvine and Baragar (1971). Alkaline geochemical 

units include alkalic basalt (WT NEPH), hawaiite (WT 

SPR , WT SUGMT), and trachybasalt (WT WBRMT), 

using their figure 10 (normative plagioclase An content 

versu color index). WT JONES and WT ANDES were 

classi 1ed as calc-alkaline andesite using their figures 6 and 

7 A. f the Idaho flows mapped by Victor Camp (table 15), 

only VC POT is classified as an alkaline basalt. The 

rem · ing geochemical units of Camp (1981), the PH 

EDE unit in northeastern Oregon, and WT OBHTI and 

WT BL TI units in the basalts of Powder River, are all 

classi 1ed as subalkaline tholeiitic basalt. 

C assification using the procedures of Wilkinson (1986, 

table 1) resulted in all units containing a mixture of basalt 

and ndesite varying from quartz- to olivine-tholeiitic 

Chemical Study of the Yakima Basalt Subgroup 9 
affinity depending on MgO content. The most magnesian 

geochemical units in the Saddle Mountains Basalt 

(ASOTIN and VC Ason and Wanapum Basalt (ROBIN) 

are classified, because of their high content of ~0 , as 

olivine subalkaline basalt. The UM FRAC geochemical 

unit is classified as a calc-alkaline tholeiitic dacite. The 

alkaline samples in the basalts of Powder River are 

classified as basanite (WT NEPH), high-Al transitional 

andesite (WT SUGMT and VC Pon, and alkali andesite 

(WT SPRMT and WT WBRMn. WT ANDES and WT 

JONES are classified as calc-alkaline andesite and dacite, 

respectively. We prefer the simpler naming using the Irvine 

and Baragar (1971) procedures. 

Bulk Rock Chemistry: Observations 

Grande Ronde Basalt 

The Grande Ronde Basalt (figures 4A-C, 5A-B) shows 

the most regular chemical variation of the three formations 

examined. All oxides and elements vary continuously over 

a limited range of MgO content (3-6 percent). Within this 

apparent continuum several different chemical subtypes, 

distinguished by small variations in MgO, Ti02

, and P2

0 5

, 

have been defined (Mangan and Wright, 1984; Mangan and 

others, 1986). The most regular major-oxide variations are 

the covariance of CaO and MgO and a less strong 

covariance of Al2

0 3 and MgO. Among the compatible 

trace elements, Sc shows the most regular variation, a 

strong positive correlation with CaO. The Sc/CaO ratio 

rises as MgO decreases. The elements Co, Cr, Ni, Cu, and 

Sr also behave as compatible elements with decreasing 

MgO. The variation of Cu suggests the separation of a 

sulfide melt at or near the liquidus temperature of these 

basalts (see Skinner and Peck, 1969). One magnesian flow 

(LH 2 in table 3; symbol "1" in figs. 4A-C and 5A-B) has 

an anomalous chemistry marked by low Ti02

, FeO, Co, and 

Sc and high Si02 and Sr. This unit has a well-defined dike 

system (table 6; Mangan and others, 1986) and covers a 

limited area in the Snake River-Blue Mountains region. A 

few other symbols plot off the main trend for a single oxide 

or element but show no correlated anomalies for other 

analyzed elements. These represent single analyses and 

perhaps reflect analytical errors. 

Incompatible trace elements and oxides show different 

degrees of enrichment with decreasing MgO (fig. 4B) or 

increasing Th (fig. SA). The elements Cs and Rb behave 

most incompatibly (greatest enrichment), followed by ~0 

and Th. The elements Ba, La, and Hf are less enriched, 

followed by Ti02, P2

0 5, Ta, Zr, and Nb. The least enrichment is shown by Yb, which remains nearly constant with 

decreasing MgO. 

The spread of data for certain constituents is greater in 

samples of the Grande Ronde Basalt having MgO less than 

3.5 percent. Particularly variable are ~0 and Th, and a 

group of samples with high values for those elements plots 

above trends defined by the rest of the Grande Ronde 

Basalt samples (fig. 4A). This is expressed on the Th variation diagram (fig. SA) by a change in slope separating the 

trend of samples with greater than 6 ppm Th from that 

defined by the rest of the data. Th continues to increase 

while the highly incompatible elements like Rb, Cs, and 

~0 may remain constant or decrease at higher values of 

Th. 

Trace-element ratios (figs. 4C, 5B) are highly variable, 

in part owing to the error amplification inherent in calculating ratios. The only ratios that remain fairly constant over 

a wide range of MgO and Th contents are K/Rb and Hf{fa. 

The compatible nature of Sr is strikingly demonstrated by 

the steep positive slopes of K/Sr and Rb/Sr. The ratio Hf/ 

Th shows a regular decrease with increasing Th or decreasing MgO, emphasizing the compatible behavior of Hf relative to Th. 

The Grande Ronde Basalt also shows regular and similar chondrite-normalized rare-earth patterns (fig. 6A). 

Samples with the lowest MgO contents have the highest 

REE contents; all patterns are enriched in light rare earths 

and slightly concave upward. A small negative Eu anomaly, expressed as the ratio of analyzed Eu to Eu measured 

by linear extrapolation between Sm and Tb, is common. 

This Eu anomaly ranges from 0.94 to 0. 77 and is not correlated with either MgO or the La/Yb ratio. The ratio La/ 

Yb is 4.0-5.5 for chondrite-normalized La contents of 55 to 

95 and increases with increasing Th (fig. 5B) or decreasing 

MgO (fig. 4C). 

The data for the Joseph volcanic unit of Kleck (1976) 

plot within the range of the low-MgO compositions in the 

Grande Ronde Basalt (table 15; symbol # in figs. 4A-C, 

5A-B, 6A). This chemistry and the stratigraphic position of 

the Joseph volcanic unit indicate that it is the latest outpouring of the Grande Ronde Basalt and formed a line of 

small shields. 

The Sr-isotope data for the Grande Ronde Basalt are 

tightly clustered near 87Sri'6

Sr = 0.7050 (fig. 7A); the total 

range is 0.7043-0.7055, including samples of McDougall 

(1976) for which Sr is the only isotopic system analyzed. 

McDougall (1976, tables 4 and 6) demonstrated a consistent difference within the Grande Ronde Basalt between 

samples collected in southeastern Washington and adjacent 

Oregon, within the area of many feeder dikes, and samples 

from central Washington. We now know that all of the 

latter samples were from flows that were also erupted from 

eastern vents (Mangan and others, 1986) but are from the 

uppermost magnetostratigraphic unit (N2

), whereas the 

eastern samples are from older units~ and N1

). Hooper 

(1984, fig. 2) generalized the relations between frlSrJ86Sr and 

magnetostratigraphy to draw a smooth trend showing 

increasing 87Srj86

Sr with decreasing age, from the Imnaha 

Basalt through the Grande Ronde Basalt to the top of the 

Wanapum Basalt. We interpret the same data to indicate a 

discontinuous jump near the· R2

-N2 unit boundary, with 

little Sr-isotopic distinction among the regionally correlated 

older flows. Within parts of units R2 and N2

• 87Srj86Sr 

10 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
increases with increasing age. The other isotopes also vary 

over fairly narrow ranges. Neodymium isotopic data, 

expressed as the difference from a chondritic value (eNd) 

generally show an inverse correlation with 87Srj86

Sr. On a 

plot of eNd against 87Srj86

Sr (see fig. 7A; Carlson, 1984a, 

fig. 3) the samples of the Grande Ronde Basalt defme a 

linear pattern with little scatter. 

Wanapum Basalt 

The Wanapum Basalt can be divided into two broad 

chemical groupings, which are also stratigraphically separate. The oldest stratigraphic unit (Eckler Mountain 

Member) is confmed to the southeastern part of the province, where the flows occupy elongate outcrop belts parallel to known linear vent systems (Swanson and others, 

1975b, 1979a). Except for P2

0 5, major oxides of the Eckler 

Mountain Member plot near or on the extrapolated trends 

for the Grande Ronde Basalt on variation diagrams using 

either MgO or Th as a base (compare figs. 4D-F and 5C-D 

with figs. 4A-C and 5A-B (symbols G, H, I, and J)); one 

unit, the basalt of Dodge, is identical in major-oxide chemistry to some magnesian flows of the Grande Ronde Basalt. 

The upper stratigraphic units of the W anapum Basalt (the 

Frenchman Springs, Roza, and Priest Rapids Members; 

symbols A-F) contain the same range of MgO (3--6 percent) as the Grande Ronde Basalt but have distinctly higher 

FeO, Ti02

, and P2

0 5 and lower Si02 contents. 

The W anapum, like the Grande Ronde, shows a strong 

covariance of CaO with MgO and Sc and an increasing Sc/ 

CaO ratio with decreasing MgO. Other chemical variations 

are less regular; for example, Ti02 and P2

0 5 are poorly 

correlated. 

Trace elements for all members of the W anapum Basalt 

plot close to trends defined for the Grande Ronde Basalt, 

although several incompatible elements (Hf, Nb, Ta, Zr, Y, 

and the REE) and Ni are systematically enriched in the 

Wanapum at the same MgO content (compare fig. 4£ with 

fig. 4B). The chondrite-normalized rare-earth patterns (fig. 

6B) for the W anapum have shapes similar to those for the 

Grande Ronde and also show an overall increase in REE 

abundance with decreasing MgO; the total REE content is 

generally higher in all but the DODGE and ROBIN geochemical units. Slightly negative Eu anomalies, as defined 

above, are present and range from 0.93 to 0.99. The La/Yb 

ratio is similar in all units, except the DODGE and ROBIN 

geochemical units, and ranges between 4 and 5 (figs. 4F, 

5D). However, the variation of La/Yb ratio with MgO or 

Th is the opposite of that in the Grande Ronde: the ratio 

decreases with decreasing MgO or increasing Th in the 

Wanapum Basalt. The basalt of Robinette Mountain has 

the flattest REE pattern of any unit in either the Grande 

Ronde or Wanapum Basalt, with a La/Yb ratio of only 2.4. 

Isotopic data for the W anapum Basalt overlap on all 

plots with those for the Grande Ronde Basalt (compare fig. 

7B with fig. 7A). Both units show a positive correlation 

of 87Srj86Sr with 208Pbf04Pb and a negative correlation with 206Pbf04Pb and eNd; 207pbf04Pb is constant at about 15.6, 

and o1

SO, which varies between +5 and+ 7, does not correlate with variations in other isotopes. 

Saddle Mountains Basalt 

The Saddle Mountains Basalt (figs. 4G-L, 5£-J-l) has a 

much wider range of chemical composition than either the 

Grande Ronde or Wanapum Basalt, yet it retains a strong 

positive correlation of CaO with MgO. Many members of 

the Saddle Mountains Basalt have major-oxide compositions similar to those of older units. We have divided the 

plots into those geochemical units broadly similar to ones 

in the Grande Ronde Basalt or the Eckler Mountain 

Member of the Wanapum Basalt (that is, relatively high 

Si02 coupled with low Ti02 and total iron) and those 

geochemical units broadly similar to the upper units of 

Wanapum Basalt (that is, relatively low Si02 coupled with 

high Ti02 and total iron). Examples of the former are 

BUFORD, POMONA, VC WEIPE, ASOTIN, SW 

HUNTZ, HUNTZ, VC LAP, and WILBUR; examples of 

the latter are LM, ELEPHANT, LEW ORCH, SPRAGUE, 

SW SPRAG, NEW, and SW NEW. However, the trace 

elements in all the geochemical units are quite distinct and 

serve to distinguish the Saddle Mountains Basalt from older 

units. Most incompatible elements, with the notable exception of Cs, are highly enriched, and some compatible elements (for example, Sc and Sr) are depleted, in the Saddle 

Mountains Basalt relative to their levels in older units. 

Comparison of the Saddle Mountains Basalt with older 

units (W anapum Basalt and Grande Ronde Basalt) is most 

easily made on an element-by-element basis at the same 

MgO content (fig. 4). Results of such comparison are 

shown in the following table (elements marginal between 

two categories are shown intermediate between two columns): 

Saddle Mountains Basalt relative to Grande Ronde Basalt 

Co Cr Sr Zn Sc Cu Ni Ba Cs lH Nb Rb Ta Th u y Zr La Yb 

Enriched X X X X X X X X X X 

Similar X X X X X X X 

Depleted X X X 

Saddle Mountains Basalt relative to Wanapum Basalt 

Enriched X X X X X X X X 

Similar X X X X X X X X X X 

Depleted X X X X 

Chemical Study of the Yakima Basalt Subgroup 11 
The Th variation diagrams (fig. 5E, 5G) for the Saddle 

Mountains Basalt show different trends for all incompatible 

elements relative to those for the Grande Ronde or Wanapum Basalt (fig. SA, 5C). Chondrite-normalized rare earth 

patterns (fig. 6C) are also steeper for a given MgO content 

than those of the Grande Ronde or Wanapum, and the La/ 

Yb ratio reaches values greater than 7 (compare fig. 4H, 4K 

with fig. 4B, 4E). Negative europium anomalies are more 

pronounced in the Saddle Mountains Basalt than in older 

units of similar major-oxide chemistry, particularly in flows 

with high total REE content. Some units of the Saddle 

Mountains Basalt show unique chemical characteristics, 

including extreme values for certain elements. Flows of the 

Ice Harbor Member have higher Sc, Hf, Nb, Ta, Zr, and 

REE and lower Th and Ni than other units in the Saddle 

Mountains Basalt. The Ice Harbor Member is richer in 

REE (fig. 6C) than many other Saddle Mountains Basalt 

units, but its La/Yb ratios of 5--6 (fig. 4L) are not especially 

high. The basalt of Goose Island (symbol B in fig. 41-K) 

has an extreme composition marked by high total iron and 

P2

0 5, far exceeding the range normally found in basalt. 

This unit also has abnormally high enrichment of Hf, Y, 

Nb, Ta, and REE. Significantly, Eu anomalies are absent 

from all geochemical units in the Ice Harbor Member, even 

the iron-rich GOOSE composition. 

The Esquatzel Member has exceptionally high values of 

Rb and Th, and the Umatilla Member has exceptionally 

high values of Ba, Rb, Th, and Eu. The Umatilla is the 

only unit within the Yakima Basalt Subgroup that has a 

pronounced positive Eu anomaly. 

Isotope data for the Saddle Mountains Basalt show that 

mean data for all isotope systems fall close to the trends 

defined by the older units extrapolated to higher values of 87Srj86

Sr. For many units of the Saddle Mountains Basalt, 

values of 87Srj86

Sr cluster around 0.7076. The samples 

forming this cluster show wider scatter in Pb isotope ratios 

than the Wanapum or Grande Ronde Basalt. Overall, the 

Saddle Mountains Basalt has higher values of ~Pbf04Pb 

and 207Pbf04Pb than the Grande Ronde and Wanapum 

Basalts. It also has generally lower values of 206Pbf04Pb, 

although the Elephant Mountain, Lower Monumental, and 

Esquatzel Members have values that equal or exceed those 

of the Grande Ronde-Wanapum sequence. Values of eNd 

and 0180 are fairly constant. Data for the following 

members of the Saddle Mountains Basalt plot at even 

higher values of 87Srj86

Sr, with wide and generally uncorrelated scatter in the other isotopes: Lower Monumental, 

Esquatzel Asotin (Huntzinger flow only), Wilbur Creek, 

and Umatilla. 

Data for additional analyzed flows are given in the 

appendix (tables 14-17), summarized in a manner similar 

to that of tables 1, 3-9, and 13. 

Comparison of Chemistry of Dikes and Flows 

Major-oxide analyses of feeder dikes have been previously published (Wright and others, 1979, 1980, 1982). 

Limited trace-element data were obtained for representative 

dikes of several geochemical units (table 6). Most dikes are 

uniquely identifiable from both trace elements and major 

oxides and correlated with specific flows or several flows 

of similar chemistry. Although one study (Ross, 1983) has 

shown individual dikes to be chemically inhomogeneous, 

and another (Taubeneck, 1970) identified inclusions of 

country rock in many dikes, the data of table 6 show 

general agreement between analyses of dikes and the average chemistry of flows they fed. Exceptions are (1) the 

Grande Ronde Basalt, where ambiguity exists for dikes 

whose chemistry matches that of flows occuring at several 

different stratigraphic levels and (2) dikes that apparently 

did not reach the surface to feed a flow (for example, 

Fairview Bar dike of Ross, 1983; analyses 78-365 and 78-

366 in table 2 of Wright and others, 1980). MgO variation 

diagrams (not shown) indicate no systematic differences in 

either MgO or other elements between flows and related 

dikes; all differences in composition are within the range of 

variation shown by the flows (Mangan and others, 1985; 

Wright, 1988) and the dikes (Wright, 1988). 

Glass Chemistry: Observations 

Fresh sideromelane is common as selvedges on dikes, 

on partially palagonitized vent spatter, in water-quenched 

pillows, and in hyaloclastic debris. Glass is also infrequently preserved on chilled flow bases or unoxidized 

pahoehoe flow tops. We systematically collected fresh 

glass and prepared grain mounts for analysis by electron 

microprobe at the Smithsonian Institution (see Wright and 

others, 1979, 1980, 1982 for analyses and description of 

method). Uncorrected analyses are given in Wright (1988), 

grouped by stratigraphic unit and geochemical unit. For 

glass-rock pairs, the N~O content (and, rarely, ~0 content) of the glass is almost always lower than that of the 

bulk rock, a relation not possible in normal basaltic crystallization. We ascribe this anomalous relation either to 

hydration and leaching during the first stage of palagonitization or to loss of sodium during electron bombardment 

(Rutherford and others, 1985). In rare instances ~0, 

Na20, or both may have been added to the glass. Helz 

( 1978) did not find a similar discrepancy in her study of 

the Ice Harbor Member, perhaps because she worked only 

with polished thin sections and analyzed only the freshest 

glass. 

We adjusted the N~O content of glass for each geochemical unit according to preliminary petrologic mixing 

calculations, which match the bulk rock with phenocrysts 

plus glass using a representative set of phenocryst compositions (R.T. Helz, unpublished data). In practice we added 

less than 0.5 percent N~O to each glass average to bring 

the N~O in the glass to about 0.1-0.2 percent higher than 

that of the corresponding rock. The adjusted data, normalized to 100 percent, and the corresponding rock chemistry 

12 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
are tabulated in tables 10-12 and plotted in figure 8. These 

glass-rock pairs demonstrate chemical trends expected from 

phenocryst-related, low-pressure crystallization. 

The glass-rock trends of figure 8 differ systematically 

from the trends defined by the bulk composition of rocks in 

the same formation, defined by the trends of figure 4. This 

is particularly evident on plots of MgO against CaO and 

Al20 3 for the Grande Ronde Basalt (fig. 8A). A similar 

observation can be made for the Wanapum (fig. 8B) and the 

Saddle Mountains (fig. 8C) Basalts, although the bulk-rock 

trends are not as closely defined as for the Grande Ronde 

Basalt. 

DISCUSSION: IMPLICATIONS FOR THE 

ORIGIN OF THE YAKIMA BASALT SUBGROUP 

In this section we use information of many kinds to 

address the fundamental questions of the melting, storage, 

and mechanics of eruption of the flood basalts of the 

Yakima Basalt Subgroup. These include the development 

of a basin to hold the basalt, evolution of a tectonic setting 

in which rapid eruption of large volumes of basalt could be 

realized, and the nature of source regions and storage areas 

consistent with the eruptive history, chemistry, and petrology of the basalts. We draw on information gained from 

the following: field mapping, stratigraphic study and age 

dating, geochemical study of the Yakima Basalt Subgroup, 

and tectonic history of the Pacific Northwest. 

Emplacement of Flows 

Geologic mapping combined with the chemical data 

presented in this paper provide insights into the nature of 

the eruptions that produced the Yakima Basalt Subgroup. 

Most eruptions were in the eastern part of the province (fig. 

3) and fed flows that moved westward down a gentle paleoslope estimated to have been about 1:1,000. Although 

ongoing subsidence beneath the central Columbia Plateau 

near Pasco (fig. 1) temporarily reversed the slope in the 

western part of the province, the largest flows, which have 

volumes exceeding 500 km3, traveled across the Pasco 

Basin and ponded against the opposed slope of the rising 

Cascade Range. Smaller eruptions produced flows of local 

extent that traveled only a few kilometers from their source. 

Some of these flows (for example, the basalts of Dodge and 

Robinette Mountain of the Eckler Mountain Member; the 

Ice Harbor Member) were confined to shallow grabens 

parallel to their vent systems. Emplacement of the voluminous flows was virtually instantaneous, as evidenced by (1) 

flat upper flow surfaces, which, together with columnar 

jointing, indicate ponding of a fluid, and (2) similar crystallinity of dike selvedges and basaltic pillows in the same 

unit separated by 100 km or more (see Shaw and Swanson, 

1970; unpub. data of C.A. Hodges for internal dikes in the 

Roza Member of the Wanapum Basalt-see Hodges, 1978; 

data of Mangan and others, 1985, 1986, p. 1317 for the 

Grande Ronde Basalt). Shaw and Swanson (1970) estimated eruption rates as high as 1 km31d per kilometer of 

fissure length for the Roza Member. Our mapping and the 

studies of Swanson and others ( 197 5b) and Mangan and 

others (1986) are consistent with this figure for the Roza 

and demonstrate similar relations for large flows of the 

Grande Ronde Basalt and flows of the Priest Rapids 

Member of the Wanapum Basalt. We do not know the 

source dikes for many of the Saddle Mountains units, but 

we assume from the widespread distribution of the flows 

that eruption rates were similar to those of the older units. 

Eruption rates for the localized flows were probably less 

than those for the plateau-covering units but still high, as 

indicated by the absence of thickening of units toward their 

vents. The viscosities of the flows, calculated from their 

chemistry (Shaw, 1972), are comparable to or higher than 

those calculated for basalts of Kilauea, known to form 

shields or to build up the rift zones in the vicinity of their 

source vents. Therefore the rates of eruption for all but the 

least voluminous flows are inferred to be higher for the 

Yakima Basalt Subgroup, in order to produce ponded flows 

even at distances of only a few kilometers. 

Swanson and others (1975b) emphasized that, although 

instantaneous eruption rates (discharges) were very high, 

the average rate at which magma was generated to supply 

the flows of the Yakima Basalt Subgroup need not have 

been particularly high. This supply rate for the period of 

maximum activity (obtained by dividing the total volume of 

the Grande Ronde and Wanapum Basalts by the length of 

time during which eruptions occurred) is about 0.075 km3

/ 

yr, close to the magma supply rate of 0.1 km3/yr currently 

estimated for Kilauea (Swanson, 1972). If the supply rate 

is equated with the melting rate in the mantle, then magma 

that fed the most voluminous individual flows in the Yakima Basalt Subgroup required 5,000-20,000 yr to accumulate before eruption. 

Magma Storage Before Eruption 

The most voluminous flows in the Yakima Basalt 

Subgroup have volumes comparable to those of large 

eruptions of ash-flow tuff, yet no evidence exists for 

surface deformation in the form of calderas associated with 

vent areas. Evidence is also lacking for the existence of 

discrete volcanic centers or of rhyolites, both of which are 

associated with basaltic provinces known to have crustal 

magma reservoirs (for example, Iceland and the Snake 

River Plain). Deformation broadly contemporaneous with 

volcanism took place in the western part of the Columbia 

Plateau (compressional folding; Reidel, 1984), the central 

part (shallow basining), and the eastern part (formation of 

complex faulted basins; Hooper and Camp, 1981). 

Discussion 13 
Evidence is not convincing, however, that this deformation 

is directly or specifically connected with large eruptions. 

Therefore the observations favor magma storage at deep 

crustal or subcrustal depths. 

In general the chemical variations within the Yakima 

Basalt Subgroup do not fit simple phenocryst-related fractionation in shallow reservoirs (that is, total pressure ~200 

MPa, depth ~6 km). Stratigraphically adjacent units do not 

show a simple chemical relation to one another, in terms 

of either bulk-rock chemistry or glass-rock trends. Aphyric 

and porphyritic flows within the same stratigraphic unit (for 

example, the Frenchman Springs Member or the basalt of 

Dodge of the Eckler Mountain Member) are chemically 

identical, a relation that seems to deny the possibility of 

crystal accumulation. Incompatible-element enrichments 

vary greatly with either decreasing MgO or increasing Th, 

inconsistent with low-pressure crystallization of olivine, 

pyroxene, and plagioclase. In general, Cs, Rb, K2

0, and Th 

show enrichment of as much as twice that shown by Hf, Zr, 

La, Ta, and P20 5 for a given decrease in MgO (fig. 4). All 

these observations contrast with those from basalt erupted 

in ocean-ridge and oceanic-island settings, where abundant 

evidence exists of shallow crystal fractionation and accumulation superimposed on chemical variation related to 

deeper processes. 

One reviewer of this paper (J. Pallister) pointed out that 

the chemical data plot near the low-pressure cotectic in the 

simplified basalt system and suggested that this is evidence 

for crustal storage. However, this relation does not prove 

crustal storage; most basalts with fairly low MgO will plot 

near the low-pressure cotectic in the simplified basalt system, irrespective of their origin. 

The chemical variations thus are not consistent with 

simple crystal fractionation at low pressure. They do not, 

however, prove the complete absence of crustal storage, 

because more complex models of crystallization combined 

with assimilation or replenishment of melt might satisfactorily explain the chemical data. For example, Helz (1978, 

1980) has shown that some of the basalt in the Ice Harbor 

Member experienced intracrustal storage (pressure 350 

MPa, depth 10 km). Of the large-volume flows, the 

Pomona Member is the only one that might have undergone 

crustal storage, because its phenocryst assemblage is similar to that of the basalt of Martindale of the Ice Harbor 

Member studied by Helz (1978). 

Finally, there is evidence for sulfur saturation of magma 

in storage. Compatible behavior of sulfophile elements, 

particularly Cu, implies the existence at near-liquidus 

temperatures of an immiscible sulfide liquid in much 

magma of the Yakima Basalt Subgroup (see also Skinner 

and Peck, 1969). The former existence of such liquid has 

been confirmed by the identification of spherical blebs of 

crystalline sulfides found during electron microprobe traverses across dike selvedges (R.T. Helz, unpub. data). 

Nature of the Source Mantle 

Inferences Based on Geochemical Data 

The following geochemical observations need to be 

explained in any satisfactory model of magma generation 

for the Yakima Basalt Subgroup. In themselves they also 

provide some limitations on the chemistry and mineralogy 

of the source mantle. 

1. MgO and CaO are correlated with a slope of about 1.2 

for all formations in the Yakima Basalt Subgroup. 

This correlation holds independent of other chemical 

variations (fig. 4). Helz (1978, p. 211) pointed out that 

this ratio matches that in clinopyroxene over a considerable range of pressure and is also typical of melt 

increments derived from partial melting of clinopyroxene-rich sources. That Sc also varies with CaO is 

consistent with clinopyroxene fractionation. Therefore 

we propose, following Helz (1978), that the magma of 

the Yakima Basalt Subgroup equilibrated with clinopyroxene at some stage in its history. 

2. Chondrite-normalized REE patterns are enriched in 

light rare earths and are concave upward. The La/Yb 

ratio is relatively low (4-5.5) and fairly uniform in the 

Grande Ronde Basalt, most of the Wanapum Basalt, 

and many members of the Saddle Mountains Basalt. 

The shape of the rare-earth patterns and, as with the 

CaO/MgO ratio, the similarity of all rare-earth patterns 

independent of other chemical variations are consistent 

with equilibration with clinopyroxene either as a melting residue or during storage. The absence of high 

values of the La/Yb ratio and of significant negative 

europium anomalies disallow the presence of garnet or 

plagioclase as significant residual or fractionating 

phases, assuming that the source and storage regions 

were not subjected to unusually high oxygen fugacities. 

3. Each formation boundary involves significant chemical 

changes that reflect changes in the melting regime. 

a. Grande Ronde-Wanapum. 

The Frenchman Springs, Roza, and Priest 

Rapids Members represent a major shift to 

magma with less Si02

, more FeO and Ti02, and 

higher content of incompatible elements when 

compared at the same MgO content. The shift in 

major-oxide chemistry occurred over a short time 

interval (within one magnetic polarity epoch). 

The Eckler Mountain Member is a transition unit; 

it shows slight trace-element enrichment but retains a chemistry characterized by high Si02 and 

low FeO and Ti02

, similar to that of the underlying Grande Ronde Basalt. 

Isotopic ratios remain the same across the 

Grande Ronde-Wanapum boundary. Values of 87Sr/'6Sr (fig. 7) are 0. 7043-0.7055 for the Grande 

14 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
Ronde Basalt and 0.7049-0.7055 for the Wanapum. The aggregate volume of the Wanapum 

Basalt is about 7 percent that of the Grande 

Ronde Basalt (Tolan and others, 1987). The 

length of time during which eruptions occurred is 

too poorly known, within the limitation of present 

K-Ar ages, to prove that the supply rate changed 

across this boundary. The overall magma production rate may have begun to decrease in 

Wanapum time (see Hooper, 1982, fig. 2), 

whereas the discharge during individual eruptions 

of plateau-covering flows remained about the 

same as in Grande Ronde time. 

b. Wanapum-Saddle Mountains. 

A major time break separates the last Wanapum and first Saddle Mountains eruptions, a 

break sufficiently long to allow the cutting of 

canyons in the older formations. The magma 

production rate decreased markedly as the time 

between eruptions increased, and large-volume 

flows of the Saddle Mountains Basalt were transported westward through deep canyons and shallow valleys cut in older formations. 

A major chemical break also coincides with 

the Wanapum-Saddle Mountains boundary. The 87Srj86

Sr ratio jumps to over 0.707 for several 

Saddle Mountains units of otherwise diverse major-oxide and trace-element chemistry and widely 

separated vent systems. Some units have extremely high 87Srj86

Sr, as high as 0.715. Majoroxide chemistry of many units is similar to that of 

the Wanapum or Grande Ronde Basalt. Most 

trace elements are enriched, particularly P, Zr, Hf, 

Formation 

Member a (fig. 3) 

Grande Ronde Basalt Mostly WPB, 

some CAB,OFB 

Wanapum Basalt 

Priest Rapids WPB 

Roza WPB 

Frenchman Springs WPB 

Eckler Mountain CAB,WPB,OFB 

Saddle Mountains Basalt 

Lower Monumental WPB 

Ice Harbor CAB(GOOSE),WPB 

Buford WPB-CAB 

Elephant Mountain WPB 

Pomona WPB 

Esquatzel WPB 

Weissenfels Ridge WPB-OFB 

Asotin WPB-OFB 

Wilbur Creek CAB 

Umatilla 

Ta, Y, and Nb; K, Cs, and Rb are not as enriched 

and may in some cases be depleted relative to 

earlier geochemical units having similar majoroxide chemistry. 

The chemical variations in the Yakima Basalt 

Subgroup cannot all be explained within a common mantle source. Rather, we postulate that the 

chemical changes seen at formation boundaries 

indicate significant changes in the mantle source 

for the magma. 

4. Tectonic classification of geochemical units. 

Rocks of the Yakima Basalt Subgroup are inconsistently classified on the many published diagrams 

that use major-oxide or trace-element chemistry to 

infer tectonic setting. We classified the rocks using the 

following sources: 

a. Pearce and Cann (1973, figs. 3 and 4): Zr-Ti/100-

Y; Zr-Ti/100-Sr/2; categories are calc-alkaline 

basalt (CAB), low-potassium tholeiite (LKT), 

within-plate basalt (WPB), and ocean-floor basalt 

(OFB). 

b. Pearce and others (1977, fig. 1): Mg0-Fe0*-

Al203; categories are ocean island (01), oceanridge and floor (ORF), continental (C), orogenic 

(0), and spreading-center island (SCI). 

c. Wood (1980, fig. 1): Th-Hf/3-Ta; categories are 

N-type MORB (NOF), E-type MORB including 

tholeiitic within-plate basalt (EOF-WPT), alkaline within-plate (A WPT), and destructive platemargin (DPM). 

Results of the classification are shown in the following 

table: ( -, units that plot outside of the classification 

boundaries): 

Classification 

a (fig. 4) b c 

Mostly OFB,CAB c All DPM 

OFB c DPM 

OFB c DPM 

OFB c DPM 

OFB,LKT -CAB C,ORF(ROBIN) DPM,WPT 

(ROBIN) 

OFB c 

(GOOSE),OFB om WPT 

OFB c DPM 

OFB c DPM 

OFB Offi-ORF DPM 

OFB c DPM 

OFB Offi,C,ORF WPT 

OFB Offi-ORF DPM 

CAB c DPM 

SCI DPM 

Discussion 15 
The most consistent discrimination is that on the 

basis of major oxides using classification b (Pearce 

and others, 1977), which identifies most of the basalt 

units as belonging to a continental setting. The 

classification of Wood (1980) is apparently the least 

consistent with the known tectonic setting, for most of 

the units are classified as basalt associated with a 

destructive plate margin. This inconsistency was also 

noted by Prestvik and Goles (1985). These tabulations demonstrate the difficulty in blindly using 

chemistry to infer tectonic setting. However, the 

apparent failure of the classifications may be not so 

much a negation of the method as an indication of the 

mixed nature of the source regions for the Yakima 

Basalt Subgroup. The tectonic history of the area 

presently occupied by the Yakima Basalt Subgroup is 

complex, and the problems of classification may be 

related to chemical signatures inherited from a source 

region composed of continental, oceanic, and subducted components. 

Inferences Based on the Tectonic History 

The source region for the Yakima Basalt Subgroup 

may be further delimited by consideration of the following: 

1. History of plate interactions at the western edge of the 

North American continent. 

Hamilton and Myers (1966) suggested that the 

Idaho batholith and the Sierra Nevada batholith were 

once a continuous coastal plutonic belt, later disrupted 

by Tertiary extension, that formed a major basin in 

back of the zone of continued subduction, now represented by the Cascade Range. Consistent with this is 

the oceanic character of pre-Tertiary rocks exposed 

beneath the eastern margin of the Columbia Plateau 

(Vallier, 1977). Additional evidence for the existence 

of a back-arc basin in Tertiary time is summarized by 

Eaton (1984 and references cited there). The northnorthwest-trending zone of linear vent systems for the 

Yakima Basalt Subgroup is on the northward extension 

of the Northern Nevada rift in the Basin and Range 

province to the south (Zoback and Thompson, 1978). 

Eaton (1984, p. 292) suggests that at the beginning of 

plateau volcanism about 17 Ma, shallow crustal faulting in the Basin and Range to the south gave way to 

wholesale lithospheric rifting to the north. 

The fact that most of the presently exposed dikes 

of the Yakima Basalt Subgroup lie west of the preTertiary continental margin implies that oceanic crust 

and mantle are likely to have formed a significant part 

of the source region for the lava. Westward migration 

of the continental margin provided in addition a continental component of mantle and crust to the sources 

for the Yakima Basalt Subgroup, particularly for the 

Saddle Mountains Basalt 

2. The record of paleomagnetic rotations in the Tertiary 

rocks of the Pacific Northwest. 

The paleomagnetic history records block rotations in 

front of the back-arc basin (Simpson and Cox, 1977; 

Beck, 1980; Beck and Plumley, 1980; Magill and Cox, 

1981; a recent summary is by Fox and Beck, 1985). 

These may have contributed to the complex distribution 

of oceanic crust and mantle in the source area for the 

basalt (see also Heller and Ryberg, 1983). The tectonic 

history therefore is consistent with the existence of a 

complexly heterogeneous source region for the Yakima 

Basalt Subgroup. 

3. The present mantle structure beneath the Columbia 

Plateau. 

The mantle structure has been recently reevaluated using a variety of geophysical methods. The 

depth to the Moho has been determined to be 40 km 

using seismic refraction methods (Catchings and others, 1984; Catchings and Mooney, 1988), an increase 

from the earlier value of 30 km obtained by Hill 

(1972). The higher value agrees with analysis of 

teleseismic P-wave arrivals (Michaelson and Weaver, 

1986, fig. 10). Michaelson and Weaver's data also 

identify an east-dipping high-velocity zone extending 

well into the mantle at least as far east as the central 

plateau; they interpret this zone as the subducting Juan 

de Fuca plate. Catchings and Mooney (1988) consider 

the deep crustal and upper mantle structure beneath the 

central Columbia Plateau to be complex and atypical 

of normal deep continental crust. 

We conclude that the complex chemical variation 

within the Yakima Basalt Subgroup is related to the presence of the following types of material in the source region: 

depleted oceanic mantle, subducted oceanic crust, original 

continental mantle, and old continental crust 

SUMMARY AND SYNTHESIS: MAGMA 

GENERATION, STORAGE, AND ERUPTION OF 

THE YAKIMA BASALT SUBGROUP 

Previous Hypotheses 

Discussion of the origin of the Yakima Basalt Subgroup requires an explanation for (1) the extremely high 

extrusion rates and large flow volumes characterizing the 

eruptions of flood basalt and (2) the chemical variation and 

petrographic character of the flows making up the Yakima 

Basalt Subgroup. 

The earliest paper to discuss the distinctive character 

of flood basalt eruptions was by Shaw and Swanson (1970), 

who demonstrated the necessity for individual lava flows to 

be erupted at rates several orders of magnitude higher than 

those historically observed in active volcanic areas. They 

did not, however, address the ultimate cause of such high 

16 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
eruption rates. Swanson and others (1975b) showed that 

the magma supply rate during Grande Ronde Basalt time 

(the time of maximum activity) was actually not excessive 

compared to that of other basaltic provinces characterized 

by lower discharge rates for individual eruptions. This 

finding indicates that the distinctive origin of flood basalts 

is related to the mechanics of storage and extrusion rather 

than to unusual conditions accompanying melting. Cox 

(1980) provided a general model for the origin of flood 

basalts that involved emplacement of thick sills at the crustmantle boundary and occasional release of magma to the 

surface through deep crustal fractures; in this model the 

magma is erupted at high rates because of the high differential pressure that results when the lower lithosphere is 

fractured. 

The earliest statement regarding the petrogenesis of the 

basalts was made by Waters (1961, p. 583), who concluded 

that the different units of the then-named Columbia River 

Basalt were "products from separate magmatic hearths, and 

not differentiates of a hypothetical uniform magma." Many 

years later, McDougall (1976) postulated that the basalt 

was produced by partial melting of the upper mantle following diapiric upwelling of a peridotite having low to 

moderate water content. He further postulated that the 

basalt underwent extensive olivine fractionation and some 

crustal contamination at low pressures before eruption in an 

extensional environment analagous to that of a back-arc 

basin. Thompson (1977; see also Thompson and others, 

1983) also postulated formation of the basalt in a back-arc 

basin and pointed out that subducted oceanic crust could 

not be ruled out in considering the petrogenesis. Helz 

(1978) was the first worker to develop a comprehensive 

model for the origin of the Ice Harbor Member (of the 

Saddle Mountains Basalt). She postulated that the four 

types of basalt in the member represented separate partial 

melting events in a mantle source dominated by clinopyroxene. The immediate source regions for two of the basalt 

types (basalt of Basin City and basalt of Goose Island) were 

at pressures greater than 1 GPa, and the mechanism of 

magma release was considered to be deep continental rifting. The other two units (basalt of Martindale and basalt of 

Indian Memorial) underwent brief storage at crustal levels 

(pressures of 300-400 MPa) before erupting to the surface. 

This model was extended to discuss the origin of the entire 

Yakima Basalt Subgroup (Helz and Wright, 1982, 1987), 

particularly regarding the need for a pyroxene-rich source. 

A metasomatic event was postulated to have preceded the 

first eruption of the Saddle Mountains Basalt. Helz (1978, 

p. 215) also made a detailed criticism of the model of 

Thompson (1977) and showed that many of Thompson's 

assumptions did not fit the field evidence or chemical data. 

Cox (1980), in his general model for flood-basalt genesis, postulated a peridotite source, a picritic primary 

magma, and extensive fractionation of olivine, augite, and 

plagioclase to produce the observed flood-basalt sequences 

around the world. He did not specifically infer the origin 

of the Columbia River Basalt, but his model agrees with the 

earlier specific model of McDougall (1976). 

Duncan (1982) proposed that eruptions of the Columbia 

River Basalt Group were triggered by a hot spot that is 

presently located beneath Yellowstone and which he inferred to have previously formed an oceanic volcanic lineament in early Tertiary time. Duncan related late Eocene 

and Oligocene volcanism in the Coast Range, Miocene 

volcanism on the Columbia Plateau, and the basalt of the 

Snake River Plain and Yellowstone to westward migration 

of the North American plate over this hot spot. 

Reidel (1983) accepted the idea that a pyroxene-rich 

mantle produced melts of the Grande Ronde Basalt that 

were stored and partly crystallized in deep crustal storage 

areas. He explained the chemical character of the Grande 

Ronde Basalt by discontinuous mixing of freshly melted 

magma with previously stored magma undergoing fractionation of plagioclase, augite, and olivine. 

Hooper (1984) postulated large (>700 km3

) storage 

reservoirs near the crust-mantle boundary as a source for 

the more voluminous units of the Columbia River Basalt 

Group. He accepted Cox's (1980) idea that primary 

magma was melted from a peridotite source and that subsequent fractionation of olivine, augite, and plagioclase 

yielded the fundamental chemical character of the basalt. 

Hooper also recognized the need for crustal assimilation in 

an open replenished magma system and for a metasomatic 

component to explain some of the chemical variation. 

Carlson and others (1981) and Carlson (1984a, b) have 

provided a comprehensive model for the origin of the 

Columbia River Basalt Group through analyses of four 

isotopic series: Sr, Nd, Pb, and 0. Carlson's work builds 

on earlier studies by McDougall (1976), DePaolo and 

Wasserburg (1979), Nelson (1983), and Church (1985). 

Carlson's model combines initial mantle heterogeneity with 

fractionation and crustal contamination to explain the isotopic data. He interprets the chemistry of the Yakima Basalt 

Subgroup in terms of interaction of at least four end 

members: (Cl) mantle depleted in incompatible-elements, 

(C2) mantle contaminated by subducted oceanic sediment, 

(C3) metasomatically enriched subcontinental lithosphere, 

and (C4) upper crust. 

Isotopic values for these end members are tabulated 

below (Carlson, 1984a, table 4) and plotted in figure 7 

using symbols 1, 2, 3, and 4, respectively. 

C1 C2 C3 C4 

87Sr/'6

Sr 0.7035 0.7038 0.7076 0.715 

ENd +6.5 +4.5 -6.0 -30.0 

206pbf04pb 18.77 19.09 18.66 17.0 

2o'Pbfo4pb 15.51 15.65 15.65 15.52 

208pbf04pb 38.28 28.73 39.44 38.5 ~18Q +5.6 +6.1 +5.8 +14.0 

Summary and Synthesis 17 
We consider Carlson's model to provide a good framework within which to examine the Yakima Basalt Subgroup, but we recognize the difficulties in reconciling 

quantitatively the isotopic data with the major-oxide and 

trace-element chemistry. 

Synthesis 

We favor a model emphasizing the following points: 

1. Following Cox (1980) we postulate storage of Yakima 

Basalt Subgroup melt in large sill-like reservoirs at the 

base of the crust (about 40 km deep and at 1.2 GPa 

pressure). If these storage reservoirs were located 

directly beneath the longest linear vent systems, and if 

their volumes were made equal to that of a representative large-volume flow, minimum dimensions of the 

stored magma body would be 150 by 15 by 0.5 km. 

The 40-km depth would provide the energy for eruption to the surface when the crust was disrupted by 

deep continental rifting; draining of such deep sills 

during flood-basalt eruptions would not be likely to 

produce significant surface deformation. At the estimated magma supply rate of 0.075 km3

/yr (Swanson 

and others, 1975b), such reservoirs would take 

10,000-20,000 yr to accumulate magma for the largest 

eruptions. Presumably, smaller eruptions would tap 

reservoirs that were at an earlier stage of development 

after only a few hundreds or thousands of years of 

magma accumulation. These estimates are minimum 

values because we do not know what percentage of 

magma in storage actually was erupted. 

2. Little evidence exists for fractionation of olivine, 

augite, and plagioclase, as postulated in the Cox (1980) 

and Hooper (1984) models. Helz's (1978) experimental results on the Ice Harbor Member show olivine to 

be barely on the liquidus at high pressure for compositions more magnesian and less silicic than most of 

the large-volume flows. The basalt flows are characterized by small negative europium anomalies that are 

not, however, correlated with MgO content, degree of 

incompatible-element enrichment, total rare-earth content, or other possible indicators of fractionation or 

degree of melting. Thus we do not interpret the presence of the europium anomalies as caused by extensive 

plagioclase fractionation. The shape of rare-earth 

patterns, their near parallelism in all units of the 

Yakima Basalt Subgroup, and the CaO-MgO coherence are also consistent with the evidence against 

extensive plagioclase fractionation and argue for melt 

in equilibrium with clinopyroxene and probably derived from a pyroxene-rich source. Possibly, however, 

picritic melt was produced initially, and ultramafic 

cumulate contributed to the process of underplating the 

lithosphere (see below) after ponding of less mafic 

magma at the base of the lithosphere. This hypothesis 

requires a significantly higher magma production rate 

than that estimated from the eruption rates given 

above. 

Our inference that the magma was primary melt 

from a pyroxene-rich mantle is made on the basis of 

the extremely large volume of olivine-rich primary 

magma that would be required to produce such large 

volumes of uniform magma, as well as on the absence 

of any olivine-controlled (picritic) flows in the Yakima 

Basalt Subgroup. This inference has received support 

from high-pressure experiments conducted by E. Takahashi, who postulates (Takahashi, 1988) that the 

chemical trends in the Grande Ronde Basalt are consistent with a high and varying degree of partial melting 

from a source chemically similar to midocean-ridge 

basalt at a pressure of 2.25 GPa corresponding to a 

depth of 70 km. These data are consistent with the 

model presented by Helz and Wright (1987). 

3. Continental crustal underplating (Lachenbruch and 

Sass, 1978; Furlong and Fountain, 1986) is attractive 

as a mechanism to explain both the seismic velocity 

structure and the presence of large bodies of melt 

stored at the base of the lithosphere. Whether magma 

is released as flood basalt may depend critically on the 

tectonics of shallower regions. Lachenbruch and Sass 

(1978) show that rapid extension, as in the Basin and 

Range province in Nevada, results in emplacement of 

large quantities of basaltic magma within the lithosphere; this magma serves as a heat source for crustal 

melting and production of large-volume silicic melts. 

Slower extension, as across the Columbia Plateau, may 

allow deep crustal rifting to directly tap the basaltic 

magma emplaced at the base of the lithosphere, with 

little crustal interaction during transport to the surface. 

The chemical and isotopic variations within each 

formation of the Yakima Basalt Subgroup are a function of small-scale source heterogeneity, as well as of 

differences in rate and degree of partial melting and 

interaction with continental crust; the latter processes 

are important only for certain units. The isotopic 

evidence for source heterogeneity and crustal interaction are neatly summarized by Carlson and others 

(1981) and Carlson (1984a). Major and abrupt 

changes in chemical composition at the top of the 

Eckler Mountain Member and the top of the Wanapum 

Basalt must, however, be ascribed to fundamental 

changes in the source composition, most likely owing 

to some form of metasomatism, as first suggested by 

Helz and Wright (1982) and amplified later (Helz and 

Wright, 1987). 

Some units underwent a brief period of crustal 

storage, as for example the basalt of Martindale of the 

Ice Harbor Member (Helz, 1978, 1980). Of the largevolume units, the Pomona Member is the only one 

whose petrography indicates a period of crustal stor18 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
age. Other members of the Saddle Mountains Basalt, 

such as the Lower Mounumental (source unknown but 

at least as far east as western Idaho), the Esquatzel 

(source unknown), and the Umatilla (source in 

southeastemmost Washington), must have had specific 

interaction, either melt-rock or rock-rock, with (Precambrian?) continental crust in order to explain their 

anomalous isotopic signatures. 

Once eruption was initiated, most flows must 

have developed their present phenocryst assemblage 

near the surface or after pending. Possibly some units 

were superheated on eruption, depending on the phase 

relations and on the rate of heat loss during transport 

to the surface. The presence of phenocrysts in dikes 

that fed porphyritic flows implies formation of those 

phenocrysts before eruption. However, even scattered 

large plagioclase phenocysts show no evidence of either concentration or flow orientation, so we infer that 

they could have formed in a turbulent environment just 

before eruption or after pending. 

Some flows have an unusual posteruption history. 

Hooper (1985) and Reidel and Fecht (1987) make 

compelling cases for the mixing of two independently 

generated magmas before and during eruption to the 

surface or after pending or both. We have also determined that at least one thick flow of the Grande Ronde 

Basalt shows evidence of contemporaneous eruption 

and mixing in a single cooling unit of lava of mixed 

chemistry. The flows of the Roza Member show 

peculiar structures similar to ring dikes (Hodges, 

1978). We have determined that the glassy selvages 

on these dikes have the same chemical composition as 

that of both the fresh sideromelane at Roza vents and 

the unpalagonitized pillow selvages where the Roza 

went into water far from its source. Hodges infers that 

these dikes originated from within the basalt, and we 

infer that they may have formed over areas where 

magma was being fed directly into an already ponded 

flow. 

The structural evolution of the plateau was 

marked throughout the flood-basalt eruptions by uplift 

of the Rocky Mountains to the east and the Cascades 

to the west and subsidence of the area between. Eruptions of the Yakima Basalt Subgroup may have indirectly accelerated basining and other structural adjustments in the Columbia Plateau. The Grande Ronde 

and Wanapum flows having the largest volumes temporarily masked the deformation and formed a fairly 

flat surface of ponded basalt. The ancestral Columbia 

River system was antecedent to the Cascades and carried many of these flows beyond the Plateau to or near 

the Pacific Ocean (Tolan and others, 1984). The 

longer time intervals between eruptions of the Saddle 

Mountains Basalt allowed a more mature drainage to 

develop. By the beginning of Saddle Mountains time, 

the ancestral Snake-Clearwater system and most of its 

major tributaries had formed on the Plateau (Swanson 

and others, 1975a; Fecht and others, 1986; Waitt and 

Swanson, 1987). Flows of the Saddle Mountains 

Basalt were channeled, and some moved great distances, pending against the rising Cascades. The 

Pomona Member is the only one that traversed both the 

ancestral Snake-Clearwater and Columbia River drainages, reaching the coast and pouring into the Pacifc 

Ocean (Tolan and others, 1984). The eruptions came 

to a gradual end; the last three events, of decreasing 

size, are dated at 10.5 Ma (Elephant Mountain Member), 8.5 Ma (Ice Harbor Member), and 6.0 Ma (Lower 

Monumental Member). Subsidence continued in the 

Pasco Basin through at least the Pliocene, until 

isostatic equilibrium was reestablished. 

REFERENCES CITED 

Anderson, J.L., Beeson, M.H., Bentley, R.D., Fecht, K.R., 

Hooper, P.R., Niem, A.R., Reidel, S.P., Swanson, D.A., Tolan, T.L., and Wright, T.L., 1987, Distribution maps of stratigraphic units of the Columbia River Basalt Group, in 

Schuster, I.E., ed.: Selected papers on the geology of Washington: Washington Division of Geology and Earth Resources Bulletin 77, p. 183-195. 

Basaltic Volcanism Study Project, 1981, Basaltic volcanism on 

the terrestrial planets: Elmsford, New York, Pergamon Press, 

1286 p. 

Beck, M.E., Jr., 1980, Paleomagnetic record of plate-margin tectonic processes along the western edge of North America: 

Journal of Geophysical Research, v. 85, p. 7115-7131. 

Beck, M.E., Jr., and Plumley, P.W., 1980, Paleomagnetism of 

intrusive rocks in the Coast Range of Oregon: microplate 

rotations in middle Tertiary time: Geology, v. 8, p. 573-577. 

Beeson, M.H., Fecht, K.R., Reidel, S.P., and Tolan, T.L., 1985, 

Regional correlations within the Frenchman Springs Member 

of the Columbia River Basalt Group: new insights into the 

middle Miocene tectonics of northwestern Oregon: Oregon 

Geology, v. 47, p. 87-96. 

Bingham, J.W., 1970, Several probable source vents for the Roza 

and Priest Rapids type basalt in Whitman and Adams Counties, Washington, in Gilmour, E.H., and Stradling, Dale., eds., 

Proceedings of the Second Columbia River Basalt Symposium: Cheney, Eastern Washington State College Press, p. 

171-172 -

Camp, V.E., 1981, Geologic studies of the Columbia Plateau: Part 

II. Upper Miocene basalt distribution reflecting source locations, tectonism, and drainage history of the Clearwater 

embayment, Idaho: Geological Society of America Bulletin, 

v. 92, pt. I, p. 669-678. 

Carlson, R.W., 1984a, Isotopic constraints on Columbia River 

flood basalt genesis and the nature of the subcontinental 

mantle: Geochimica et Cosmochimica Acta, v. 48, p. 

2357-2372. 

--1984b, Tectonic influence on magma composition of 

Cenozoic basalts from the Columbia River Plateau and Northwestern Great Basin, U.S.A., in Explosive volcanism: incepReferences Cited 19 
tion, evolution, and hazards: National Research Council 

Studies in Geophysics: Washington, D.C., National Academy 

Press, p. 23-33. 

Carlson, R.W., Lugmair, G.W., and MacDougall, J.D., 1981, 

Columbia River volcanism: The question of mantle heterogeneity or crustal contamination: Geochimica et Cosmochimica 

Acta, v. 45, p. 2483-2499. 

Catchings, R.D., and Mooney, W.D., 1988, Crustal Structure of 

the Columbia Plateau: evidence for Continental Rifting: 

Journal of Geophysical Research, v. 93, p. 459-474. 

Catchings, R.D., Mooney, W.D., and Holbrook, W.S., 1984, 

Crustal structure of southeastern Washington from seismic 

refraction [abs.]: Eos, American Geophysical Union Transactions, v. 65, p. 988. 

Choiniere, S.R., and Swanson, D.A., 1979, Magnetostratigraphy 

and correlation of Miocene basalts of the northern Oregon 

coast and Columbia Plateau, southeast Washington: American Journal of Science, v. 279, p. 755-777. 

Church, S.E., 1985, Genetic interpretation of lead-isotopic data 

from the Columbia River Basalt Group, Oregon, Washington, 

and Idaho: Geological Society of America Bulletin, v. 96, p. 

676-690. 

Cox, K.G., 1980, A model for flood basalt volcanism: Journal of 

Petrology, v. 21, p. 629-650. 

DePaolo, D.J., and Wasserburg, G.J., 1979, Neodymium isotopes 

in flood basalts from the Siberian Platform and inferences 

about their mantle sources: National Acadamy of Science 

Proceedings, v. 76, p. 3056-3060. 

Duncan, R.A., 1982, A captured island chain in the coast range of 

Oregon and Washington: Journal of Geophysical Research, v. 

87, p. 10,827-10,837. 

Eaton, G.P., 1984, The Miocene Great Basin of western North 

America as an extending back-arc region: Tectonophysics, v. 

102, p. 275-295. 

Fecht, K.R., Reidel, S.R., and Tallman, A.M., 1986, Paleodrainage of the Columbia River system on the Columbia Plateau of 

Washington State-a summary: Rockwell Hanford Company, Richland, Washington, Document RHO-BWI-SA-318, 

55 p. 

Fox, K.F., Jr., and Beck, M.E., Jr., 1985, Paleomagnetic results 

for Eocene volcanic rocks from northeastern Washington and 

the Tertiary tectonics of the Pacific northwest: Tectonics, v. 

4, p. 323-341. 

Furlong, K.P., and Fountain, D.M., 1986, Continental crustal 

underplating: thermal considerations and seismic-petrologic 

consequences: Journal of Geophysical Research, v. 91, p. 

8285-8294. 

Glover, D.W., Malone, S.D., and Rohay, A.C., 1985, Crustal 

structure of the Columbia Basin, Washington, from borehole 

and refraction data [abs.]: Eos, American Geophysical Union 

Transactions, v. 66, p. 1361. 

Hamilton, W.E., and Myers, W.B., 1966, Cenozoic tectonics of 

the western United States: Review of Geophysics, v. 4, p. 

509-549. 

Haskin, L.A., Haskin, M.A., Frey, F.A., and Wildman, T.R., 1968, 

Relative and absolute terrestrial abundances of the rare earths, 

in Ahrens, L.H., ed., Origin and distribution of the elements: 

New York, Pergamon Press, p. 889-912. 

Heller, P.L., and Ryberg, P.T., 1983, Sedimentary record of 

subduction to forearc transition in the rotated Eocene basin of 

western Oregon: Geology, v. 11, p. 380-383. 

Helz, R.T., 1978, The petrogenesis of the Ice Harbor Member, 

Columbia Plateau, Washington-a chemical and experimental 

study: University Park, Pennsylvania, Pennsylvania State 

University, Ph.D. dissertation, 284 p. 

---1980, Chemical and experimental study of the Ice Harbor 

member of the Yakima Basalt Subgroup: evidence for intracrustal storage and contamination [abs.]: Eos, American 

Geophysical Union Transactions, v. 61, p. 68. 

Helz, R.T., and Wright, T.L., 1982, Inferred petrology of the 

source of the Yakima Basalt subgroup: Abstracts submitted 

to the IA VCEIJIAGC scientific Assembly on the Generation 

of Major Basalt Types, Reykjavik, Iceland August 15-22, 

1982 [unpag.]. 

---1987, A model for the origin of the Yakima Basalt Subgroup, NW USA [abs.]: Geological Society of America 

Abstracts with Programs, v. 19, no. 6, p. 388. 

Hill, D.P., 1972, Crustal and upper mantle structure of the Columbia Plateau from long range seismic-refraction measurements: 

Geological Society of America Bulletin, v. 83, p. 1639-1648. 

Hodges, C.A., 1978, Basaltic ring structures of the Columbia 

Plateau: Geological Society of America Bulletin, v. 89, p. 

1281-1289. 

Hooper, P.R., 1981, The role of magnetic polarity and chemical 

analyses in establishing the stratigraphy, tectonic evolution 

and petrogenesis of the Columbia River Basalt, in Subbarao, 

K.V., and Sukheswala, R.N., eds., Deccan volcanism and 

related basalt provinces in other parts of the world: Geological Society of India, Memoir 3, p. 362-376. 

---1982, The Columbia River basalts: Science, v. 215, p. 

1463-1468. 

---1984, Physical and chemical constraints on the evolution 

of the Columbia River basalt: Geology, v. 12, p. 495-499. 

---1985, A case of simple magma mixing in the Columbia 

River Basalt Group: The Wilbur Creek, Lapwai, and Asotin 

flows, Saddle Mountains Formation: Contributions to Mineralogy and Petrology, v. 91, p. 66-73. 

Hooper, P.R., and Camp, V.C., 1981, Deformation of tht: southeast part of the Columbia River Plateau: Geology, v. 9., p. 

323-328. 

Hooper, P.R., and Swanson, D.A., in press, Columbia River 

Basalt Group and associated volcanic rocks in the Blue 

Mountain region, in Walker, G.W., ed., Cenozoic geology of 

the Blue Mountains region: U.S. Geological Survey Professional Paper 1437. 

Irvine, T.N., and Baragar, W.R.A., 1971, A guide to the chemical 

classification of the common volcanic rocks: Canadian Journal of Earth Sciences, v. 8, p. 523-548. 

Kleck, W.D., 1976, Chemistry, petrography, and stratigraphy of 

the Columbia River Group in the Imnaha Valley region, eastem Oregon and western Idaho: Pullman, Washington State 

University, Ph.D. dissertation, 203 p. 

Lachenbruch, A.H., and Sass, J.H., 1978, Models of an extending 

lithosphere and heat flow in the Basin and Range province, in 

Smith, R.B., and Eaton, G.P., eds., Cenozoic tectonics and 

regional geophysics of the western Cordillera: Geological 

Society of America Memoir 152, p. 209-250. 

Lingley, W.S., Jr., and Walsh, T.J., 1986, Issues related to petroleum drilling near the proposed high-level nuclear waste 

repository at Hanford: Washington Geologic Newsletter, v. 

20 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
14, p. 10-19. 

Magill, James, and Cox, Allan, 1981, Post-Oligocene tectonic 

rotation of the Oregon western Cascade Range and the Klamath Mountains: Geology, v. 9, p. 127-131. 

Mangan, M.T., and Wright, T.L., 1984, Regional correlation of 

Grande Ronde Basalt flows, Columbia River Basalt Group 

[abs.]: Eos, American Geophysical Union Transactions, v. 

65, p. 1153. 

Mangan, M.T., Wright, T.L., Swanson, D.A., and Byerly, G.R., 

1985, Major oxide, trace element, and glass chemistry pertinent to regional correlation of Grande Ronde Basalt flows, 

Columbia River Basalt Group, Washington: U.S. Geological 

Survey Open-File Report 85-747, 74 p. 

---1986, Regional correlation of Grande Ronde Basalt flows, 

Columbia River Basalt Group, Washington, Oregon, and 

Idaho: Geological Society of America Bulletin, v. 97, p. 

1300-1318. 

McDougall, Ian, 1976, Geochemistry and origin of basalt of the 

Columbia River Group, Oregon and Washington: Geological 

Society of America Bulletin, v. 87, p. 777-792. 

McKee, E.H., Hooper, P.R., and Kleck, W.D., 1981, Age of 

Imnaha Basalt-oldest basalt flows of the Columbia River 

Basalt Group, northwest United States: Isochron/West, no. 31, 

p. 31-33. 

McKee, E.H., Swanson, D.A., and Wright, T.L., 1977, Duration 

and volume of Columbia River Basalt volcanism, Washington, Oregon, and Idaho [abs.]: Geological Society of America 

Abstracts with Programs, v. 9, p. 463-464. 

Michaelson, C.A., and Weaver, C.S., 1986, Upper mantle structure from teleseismic P-wave arrivals in Washington and 

northern Oregon: Journal of Geophysical Research, v. 91, p. 

209-250. 

Nathan, Simon., and Fruchter, J.S., 1974, Geochemical and paleomagnetic stratigraphy of the Picture Gorge and Yakima Basalts (Columbia River Group) in central Oregon: Geological 

Society of America Bulletin, v. 85, p. 63-76. 

Nelson, D.O., 1980, Strontium isotope and trace element geochemistry of the Saddle Mountains and Grande Ronde Basalts 

of the Columbia River Group: Corvallis, Oregon State University, Ph.D. dissertation, 224 p. 

---1983, Implications of oxygen-isotope data and trace-element modeling for a large-scale mixing model for the Columbia River Basalt: Geology, v. 11, p. 248-251. 

Pearce, J.A., and Cann, J.R., 1973, Tectonic setting of basic 

volcanic rocks determined using trace-element analysis: 

Earth and Planetary Science Letters, v. 19, p. 290-300. 

Pearce, J.A., Gorman, B.E., and Birkett, T.C., 1977, The relationship between major element chemistry and tectonic environment of basic and intermediate volcanic rocks: Earth and 

Planetary Science Letters, v. 36, p. 121-132. 

Prestvik, Tore, and Goles, G.G., 1985, Comments on petrogenesis 

and the tectonic setting of Columbia River basalts: Earth and 

Planetary Science Letters, v. 72, p. 65-73. 

Price, S.M., 1974, A geochemical classification of dikes of the 

Grande Ronde Swarm, Columbia River Basalt: Atlantic 

Richfield Hanford Co., U.S. Atomic Energy Commission 

Report ARH-SA-202, 29 p. 

Reidel, S.P., 1983, Stratigraphy and petrogenesis of the Grande 

Ronde Basalt from the deep canyon country of Washington, 

Oregon, and Idaho: Geological Society of America Bulletin, 

v. 94, p. 519-542. 

---1984, The Saddle Mountains: the evolution of an anticline 

in the Yakima fold belt: American Journal of Science, v. 272, 

p. 870-893. 

Reidel, S.P., and Fecht, K.R., 1987, The Huntzinger flow: evidence of surface mixing of the Columbia River Basalt and its 

petrogenetic implications: Geological Society of America 

Bulletin, v. 98, p. 664-677. 

Ross, M.E., 1983, Chemical and mineralogic variations within 

four dikes of the Columbia River Basalt Group, southeastern 

Columbia Plateau: Geological Society of America Bulletin, v. 

94, p. 1117-1126. 

Rutherford, M.J., Sigirdsson, Haralder, Cary, Steven, and Davis, 

Andrew, 1985, The May 18, 1980, eruption of Mount St. 

Helens: 1. Melt composition and experimental phase equilibria: Journal of Geophysical Research, v. 90, p. 2929-2947. 

Shaw, H.R., 1972, Viscosities of magmatic silicate liquids: an 

empirical method of prediction: American Journal of Science, 

v. 272, p. 870-893. 

Shaw, H.R., and Swanson, D.A., 1970, Eruption and flow rates of 

flood basalts, in Gilmour, E.H., and Stradling, Dale., eds., 

Proceedings of the Second Columbia River Basalt Symposium: Cheney, Washington, Eastern Washington State College Press, p. 271-299. 

Simpson, R.W., and Cox, Allan, 1977, Paleomagnetic evidence 

for tectonic rotation of the Oregon Coast Range: Geology, v. 

5, p. 585-589. 

Skinner, B.J., and Peck, D.L., 1969, An immiscible sulfide melt 

from Hawaii in Wilson, H.D.B., ed., Magmatic ore deposits: 

Economic Geology Monograph 4, p. 310-322. 

Stanley, W.D., 1984, Tectonic study of Cascade Range and Columbia Plateau in Washington State based upon magnetotelluric soundings: Journal of Geophysical Research, v. 89, p. 

4447-4460. 

Swanson, D.A., 1972, Magma supply rate at Kilauea volcano, 

1952-1971: Science, v. 175, p. 169-170. 

Swanson, D.A., Anderson, J.L., Bentley, R.D., Byerly, G.R., 

Camp, V.E., Gardner, J.N., and Wright, T.L., 1979b, Reconnaissance geologic map of the Columbia River Basalt Group 

in eastern Washington and northern Idaho: U.S. Geological 

Survey Open-File Report 79-1363, 26 p., 12 map sheets, scale 

1:250,000. 

Swanson, D.A., Anderson, J.L., Camp, V.E., Hooper, P.R., 

Taubeneck, W.H., and Wright, T.L., 1981, Reconnaissance 

geologic map of the columbia River Basalt Group, northern 

Oregon and western Idaho: U.S. Geological Survey Open-file 

report 81-797, 33 p., 5 map sheets, scale 1:250,000. 

Swanson, D.A., and Wright, T.L., 1981, The regional approach to 

studying the Columbia River Basalt, in Subbarao, K.V., and 

Sukheswala, R.N., eds., Deccan volcanism and related basalt 

provinces in other parts of the world: Geological Society of 

India, Memoir 3, p. 58-80. 

Swanson, D.A., Wright, T.L., Camp, V.E., Gardner, J.N., Helz, 

R.T., Price, S.M., Reidel, S.P., and Ross, M.E., 1980, Reconnaissance geologic map of the Columbia River Basalt Group, 

Pullman and Walla Walia quadrangle, southeast Washington 

and adjacent Idaho: U.S. Geological Survey Miscellaneous 

Investigations Map 1-1139, scale 1:250,000. 

Swanson, D.A., Wright, T.L., and Clem, Richard, 1975a, Intracanyon flows of Yakima Basalt along the Snake River, southReferences Cited 21 
east Washington [abs]: Geological Society of America Abstracts with Programs, v. 7, no. 5, p. 645. 

Swanson, D.A., Wright, T.L., and Helz, R.T., 197Sb, Linear vent 

systems and estimated rates of magma production and eruption for the Yakima Basalt on the Columbia River Plateau: 

American Journal of Science, v. 275, p. 877-905. 

Swanson, D.A., Wright, T.L., Hooper, P.R., and Bentley, R.D., 

1979a, Revisions in stratigraphic nomenclature of the Columbia River Basalt Group: U.S. Geological Survey Bulletin 

1457-G, p. Gl-059. 

Takahashi, Eiichi, 1988, High-pressure melting study on Columbia River basalts [abs.]: Eos, Transactions, American Geophysical Union, v. 69, p. 524. 

Taubeneck, W.H., 1970, Dikes of Columbia River Basalt in northeastern Oregon, western Idaho, and southeastern Washington, 

in Gilmour, E.H., and Stradling, Dale, eds., Proceedings of the 

Second Columbia River Basalt Symposium: Cheney, Washington, Eastern Washington State College Press, p. 73-96. 

---1978, Two new sources for Columbia River Basalt in 

western Idaho-The Slate Creek and Greer Dike Swarms 

[abs.]: Geological Society of America Abstracts with Programs, v. 10, p. 239-240. 

---1980, Diatremes in Columbia River Basalt near the crest 

of the west escarpment of the Grande Ronde Graben, northeast Oregon [abs.]: Geological Society of America Abstracts 

with Programs, v. 12, no. 3, p. 155. 

Thompson, R.N., 1977, Columbia/Snake River-Yellowstone 

magmatism in the context of western U.S.A. Cenozoic geodynamics: Tectonophysics, v. 39, p. 621-636. 

Thompson, R.N., Morrison, M.A., Dickin, A.P., and Hendry, 

G.L., 1983, Continental flood basalts ... arachnids rule OK?, 

in Hawkesworth, C.J., and Norry, M.J., eds., Continental 

basalts and mantle xenoliths: Nantwich, England, Shiva 

Publishing Limited, p. 158-185. 

Tolan, T.L., Beeson, M.H., and Vogt, B.F., 1984, Exploring the 

Neogene history of the Columbia River: Discussion and 

geologic field trip guide to the Columbia River Gorge. Part 

1, Discussion: Oregon Geology, v. 46, no. 8, p. 87-97. 

Tolan, T.L., Reidel, S.P., Beeson, M.H., Anderson, J.L., Fecht, 

K.R., and Swanson, D.A., 1987, Revisions to the areal extent 

and volume of the Columbia River Basalt Group (CRBG) 

[abs.]: Geological Society of America Abstracts with Programs, v. 19, no. 6, p. 458. 

Vallier, T.L., 1977, The Permian and Triassic Seven Devils 

Group, western Idaho and northeastern Oregon: U.S. Geological Survey Bulletin 1437, 58 p. 

Waitt, R.B., Jr., and Swanson, D.B., 1987, Geomorphic evolution 

of the Columbia Plain and River, p. 403-416 in Baker, V.R., 

Greeley, Ronald, Komar, P.D., Swanson, D.A., and Waitt, 

R.B., Jr., ch. 11 in Graf, W.L., ed, Geormorphic systems of 

North America: Boulder, Colorado, Geological Society of 

America, Centennial Special Volume 2, 643 p. 

Walker, G.W., 1973, Contrasting compositions of the youngest 

Columbia River Basalt flows in Union and Wallow a Counties, 

northeastern Oregon: Geological Society of America Bulletin, v. 84, p. 425-430. 

Ward, A.W., Jr., 1976, Petrology and chemistry of the Huntzinger 

flow, Columbia River Basalt, Washington: Atlantic Richfield 

Hanford Co., U.S. Atomic Energy Commission Report 

ARH-SA-272, 134 p. 

Waters, A.C., 1961, Stratigraphic and lithologic variations in the 

Columbia River Basalt: American Journal of Science, v. 259, 

p. 583--611. 

Watkins, N.D., and Baksi, A.K., 1974, Magnetostratigraphy and 

oroclinal folding of the Columbia River, Steens, and Owyhee 

Basalts in Oregon, Washington, and Idaho: American Journal 

of Science, v. 274, p. 148-189. 

Wilkinson, J.F.G., 1986, Classification and average chemical 

composition of common basalts and andesites: Journal of 

Petrology, v. 27, p. 31--62. 

Wood, D.A., 1980, The application of a Th-Hf-Ta diagram to 

establishing the nature of crustal contamination of basaltic 

lava of the British Tertiary province: Earth and Planetary 

Science Letters, v. SO, p. 11-30. 

Wright, T.L., 1988, Chemical analyses of rocks and glasses used 

to compute average compositions for geochemical units in the 

Yakima Basalt Subgroup, Columbia River Basalt Group, 

Idaho, Oregon, and Washington: U.S. Geological Survey 

Open-File Report 88-263, 71 p. 

Wright, T.L., Black, K.N., Swanson, D.A., and O'Hearn, Tim, 

1980, Columbia River Basalt: 1978-1979 sample data and 

chemical analyses: U.S. Geological Survey Open-File Report 

80-921, 99 p. 

---1982, Columbia River Basalt: 1980-1981 sample data and 

chemical analyses: U.S. Geological Survey Open-File Report 

82-532, 51 p. 

Wright, T.L., Grolier, M.J., and Swanson, D.A., 1973, Chemical 

variation related to stratigraphy of the Columbia River Basalt: 

Geological Society of America Bulletin, v. 84, p. 371-386. 

Wright, T.L., Swanson, D.A., Helz, R.T., and Byerly, G.R., 1979, 

Major oxide, trace element, and glass chemistry of Columbia 

River basalt samples collected between 1971 and 1977: U.S. 

Geological Survey Open-File Report 79-711, 160 p. 

Zoback, M.L., and Thompson, G.A., 1978, Basin and Range rifting in northern Nevada: clues from a mid-Miocene rift and its 

subsequent offsets: Geology, v. 6, p. 111-116. 

22 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
TABLES 3-17; FIGURES 4-9 
Table 3. Average chemical composition of geochemical units in the Grande Ronde Basalt 

[Geochemical units listed in approximate stratigraphic order, see table 1; chemical types A-E are major types repeated throughout 

section, 1 and 2 are distinctively magnesian units of local extent, and X refers to all other Grande Ronde flows. Trace elements 

followed by X are analyzed by X-ray fluorescence; all others analyzed by instrumental neutron activation. n.a., not analyzed. Data 

from which these average compositions were calculated are given in Mangan and others (1985)] 

Geochemical 

unit-------- lA lA* 3A 3A 3A 3A UNC 4A 4A 4A* 3B LH2 MG6 

Chemical type- A A c c c c X D D D c 1 2 

Major oxides (weight percent) 

Si02 54.58 54.53 53.53 53.65 54.09 53.71 54.52 54.52 53.83 53.99 53.66 53.80 51.52 

AI203 14.51 14.32 14.52 14.30 14.42 14.34 14.51 14.30 13.89 14.14 14.71 15.19 14.98 

FeO 10.93 11.08 11.34 11.31 11.17 11.34 10.20 12.10 11.62 11.72 11.21 9.40 11.83 

MgO 4.53 4.83 5.19 5.23 4.95 5.24 5.14 4.52 4.83 4.84 5.13 6.12 5.96 

CaO 8.53 8.43 9.09 9.01 8.80 8.95 8.95 7.81 8.84 8.53 8.83 10.09 9. 71 

Na20 2.84 3.04 2.81 2.84 2.81 2.91 2.89 2.83 2.88 3.00 2.77 2.88 2.76 

K20 1.42 l. 32 1.02 1.04 1.18 1.10 1.13 0.97 1.32 1.22 1.31 0.69 0.60 

Ti02 l. 80 l. 73 1.74 1.83 l. 81 1. 75 1.91 2.05 1.97 1. 86 1.72 1.13 1. 70 

P205 0.36 0.28 0.26 0.29 0.32 0.23 0.32 0.33 0.32 0.27 0.27 0.26 0.32 

1\.fuO 0.18 0.18 0.21 0.18 0.19 0.19 0.17 0.19 0.21 0.19 0.20 0.16 0.18 

Total 99.68 99.74 99.71 99.68 99.74 99.76 99.74 99.62 99.71 99.76 99.81 99.72 99.56 

Trace elements (parts per million) 

Ba 579 502 464 458 537 472 507 450 494 439 518 367 407 

BaX 577 537 465 469 491 454 487 433 512 439 500 n.a. 0 

Co 37.30 33.60 38.80 38.50 40.0 38.60 40.80 39.80 38.60 38.10 39.50 34 40.10 

Cr 43.40 39.10 52.40 49.90 60 54.90 51 3 1 25.30 23.80 48.90 84.50 99.80 

Cs 0.90 0.85 0.70 0.50 1.10 0.65 0.92 0.39 0.80 0.50 0.70 n.a. 0.43 

Hf 4.14 3.70 3.70 4.05 3.97 3.85 4.03 3.81 4.10 3.90 3.80 2.77 3.20 

NbX 11 13 11 1 3 16 11.50 12 12 15 14 12 n.a. 0 

Rb 30.60 29.50 26.50 29 30 30.50 35.50 27 33 27 35.20 17.20 26.50 

RbX 32.70 34.50 28 23 26 29.50 32 24 3 1 29 31 26 0 

SrX 334 325 333 315 363 335 322 321 337 338 328 486 0 

Ta 0.75 0.72 0.70 0.67 0.76 0.73 0.74 0.71 0.78 0.72 0.69 0.43 0.62 

Th 4.19 3.60 3.20 3.60 3.66 3.40 3.53 3.22 3.79 3.60 3.63 1.85 2.38 

u 1.10 1.05 0.80 0.88 n.a. 0.75 1.20 n.a. n.a. 0.80 0.80 n.a. 0.90 

YX 33.30 31 3 1 3 1 40 32 30 30 33 32 30 23 0 

Zn 132 114 113 122 138 118 127 120 130 112 142 122 123 

Zr 163 160 115 207 n.a. 135 150 213 144 76 200 n.a. 147 

ZrX 170 167 158 157 175 158 164 157 173 164 161 119 0 

Sc 34.50 31 36.30 37.20 36.70 37.80 37 36.10 36.80 35.20 37.10 36.80 38.30 

La 22.10 18.50 1 8 19.40 20.80 19.50 19.90 18.10 20.40 19 20.10 15.60 16 

Ce 43.20 38.50 35.50 38.80 43.10 38 38.80 36.30 39.90 37 40.20 30.90 32.30 

Nd 26.60 24 20.50 23 23.70 22.50 24.50 28 27 23 23.50 18.40 21.30 

Sm 6 5.30 5.10 5.40 6 5.60 5.60 5.70 5.90 5.20 5.60 4.30 3.80 

Eu 1.61 1.57 1.58 1.59 l. 81 1.64 1.62 1.42 1.66 1.57 1.69 1.25 1.44 

Gd 5.30 5.30 6.20 6.30 n.a. 4.60 6.10 5.40 6.10 4.80 5.90 n.a. 4.80 

Tb 0.96 0.84 0.84 0.95 1.10 0.90 0.98 0.90 0.85 0.82 1 0.77 0.78 

Yb 3.13 2.90 3.15 3.30 3.12 3.25 3.17 3.03 3.20 3.10 3.12 1.93 2.90 

Lu 0.52 0.43 0.47 0.47 0.56 0.48 0.49 0.51 0.52 0.46 0.51 0.41 0.41 

Cu 31.30 29.50 36 34 n.a. 34 36 36 28 28 33 n.a. 0 

Ni 15.70 10.50 18 14 n.a. 15.50 16 17 16 8 14 n.a. 0 

Normalized major-oxide contents (weight percent) 

Si02 54.76 54.67 53.69 53.82 54.23 53.84 54.66 54.73 53.99 54.12 53.76 53.95 51.75 

Al203 14.56 14.36 14.56 14.35 14.46 14.37 14.55 14.35 13.93 14.17 14.74 15.23 15.05 

FeO 10.97 11.11 11.37 11.35 11.20 11.37 10.23 12.15 11.65 11.75 11.23 9.43 11.88 

MgO 4.54 4.84 5.21 5.25 4.96 5.25 5.15 4.54 4.84 4.85 5.14 6.14 5.99 

CaO 8.56 8.45 9.12 9.04 8.82 8.97 8.97 7.84 8.87 8.55 8.85 10.12 9.75 

Na20 2.85 3.05 2.82 2.85 2.82 2.92 2.90 2.84 2.89 3.01 2.78 2.89 2.77 

K20 1.42 1.32 1.02 1.04 1.18 1.10 1.13 0.97 1.32 1.22 1.31 0.69 0.60 

Ti02 1. 81 l. 73 1.7 5 1.84 1. 81 1.75 1.91 2.06 1.98 1.86 1.72 1.13 1. 71 

P205 0.36 0.28 0.26 0.29 0.32 0.23 0.32 0.33 0.32 0.27 0.27 0.26 0.32 

MnO 0.18 0.18 0.21 0.18 0.19 0.19 0.17 0.19 0.21 0.19 0.20 0.16 0.18 

Total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 

24 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
Table 3. Average chemical composition of geochemical units in the Grande Ronde Basalt-Continued 

Geochemical 

unit-------- 2B 

Chemical type - 2 

SA 

B 

SA 

E 

SA 

E 

SA 

E 

SA* 

E 

2C 

E 

2C 

B 

SB 

B 

3C 

E 

3C 

c 3C* c c 

Si02 

Al203 

FeO 

MgO 

CaO 

Na20 

K20 

Ti02 

P205 

MnO 

Total 

Ba 

BaX 

Co 

Cr 

Cs 

Hf 

NbX 

Rb 

RbX 

SrX 

Ta 

Th 

u 

YX 

Zn 

Zr 

ZrX 

Sc 

La 

Ce 

Nd 

Sm 

Eu 

Gd 

Tb 

Yb 

Lu 

Cu 

Ni 

Si02 

Al203 

FeO 

MgO 

CaO 

Na20 

K20 

Ti02 

P205 

MnO 

Total 

52.44 

14.67 

11.45 

5.51 

9.76 

2.92 

0.75 

1.56 

0.29 

0.18 

99.53 

432 

393 

38.4 

110 

0.89 

3.12 

13 

19.1 

26.0 

381 

0.62 

2.26 

0.69 

30.7 

125 

179 

131 

37.5 

17.3 

34.2 

22.3 

5.1 

1.55 

4.6 

0.88 

2.69 

0.44 

49.5 

20.0 

56.69 

13.56 

11.01 

3.43 

7.07 

3.00 

2.16 

2.28 

0.41 

0.20 

99.81 

843 

n.a. 

35.1 

6.1 

1.39 

4.90 

n.a. 

56.4 

n.a. 

n.a. 

0.64 

5.91 

n.a. 

n.a. 

134 

n.a. 

n.a. 

32.4 

30.0 

58.5 

36.9 

7.5 

2.20 

n.a. 

1.29 

3.78 

0.64 

n.a. 

n.a. 

55.59 

13.77 

11.95 

3.74 

7.20 

2.91 

1.81 

1.96 

0.34 

0.19 

99.46 

733 

689 

37.3 

6.9 

1.62 

4.96 

14 

57.0 

54.70 

341 

0.93 

6.40 

1.59 

34.0 

130 

194 

199 

31.3 

28.0 

53.7 

31.8 

6.8 

1.83 

7.3 

1.18 

3.53 

0.51 

13.8 

6.4 

56.04 

14.06 

11.16 

3.67 

7.24 

3.02 

2.03 

1.95 

0.34 

0.19 

99.70 

Major oxides (weight percent) 

55.99 

13.91 

11.62 

3.72 

6.95 

3.23 

1.70 

1.97 

0.35 

0.18 

99.62 

55.94 

13.46 

11.63 

3.70 

7.31 

2.90 

1.94 

2.12 

0.31 

0.20 

99.51 

56.46 

13.98 

11.17 

3.62 

7.09 

3.31 

1.75 

1.92 

0.28 

0.18 

99.76 

54.80 

13.35 

12.90 

3.61 

6.93 

3.36 

1.69 

2.38 

0.42 

0.20 

99.64 

Trace elements (parts per million) 

759 

767 

37.3 

11.6 

1.37 

4.88 

13 

53.1 

49.0 

339 

0.99 

6.15 

1.70 

34.0 

138 

144 

190 

31.8 

26.9 

53.7 

30.5 

6.7 

1.89 

6.6 

1 

3.09 

0.52 

15.0 

6.2 

713 

705 

37.7 

10.0 

0.81 

4.90 

15 

51.8 

48.0 

324 

0.93 

6.58 

1.56 

35.0 

138 

n.a. 

190 

32.1 

27.0 

54.2 

28.3 

6.8 

1.99 

8.4 

1.13 

3.17 

0.54 

13.0 

6.5 

777 

782 

35.9 

8.5 

1.60 

4.97 

11 

53.0 

57.0 

336 

0.90 

6.30 

1.80 

34.0 

132 

243 

201 

31.8 

26.7 

51.0 

28.0 

6.3 

1.80 

6.6 

1.18 

3.48 

0.53 

17.0 

7.0 

679 

704 

35.2 

9.4 

0.94 

4.75 

16 

51.3 

53.7 

333 

0.90 

6.27 

1.59 

35.0 

136 

189 

189 

30.7 

27.6 

52.0 

30.0 

6.5 

1.84 

6.5 

0.99 

3.41 

0.50 

n.a. 

n.a. 

736 

702 

36.8 

3.5 

0.85 

5.00 

15 

48.7 

51.3 

336 

0.95 

5.73 

1.43 

39.3 

142 

200 

196 

33.1 

27.8 

53.8 

31.0 

7.1 

1.98 

7.1 

1.25 

3.63 

0.55 

13.0 

5.2 

55.42 

13.80 

12.13 

3.41 

7.01 

3.15 

1.99 

2.27 

0.38 

0.20 

99.76 

746 

n.a. 

36.1 

n.a. 

1.37 

4.80 

n.a. 

46.5 

n.a. 

n.a. 

0.86 

5.62 

n.a. 

n.a. 

133 

n.a. 

n.a. 

32.8 

28.1 

55.2 

29.9 

7.0 

2.19 

n.a. 

1.07 

3.54 

0.56 

n.a. 

n.a. 

Normalized major-oxide contents (weight percent) 

56.24 

14.13 

10.92 

3.73 

7.15 

3.02 

2.20 

1.88 

0.32 

0.18 

99.77 

707 

715 

33.7 

10.8 

1.33 

4.61 

14 

56.0 

53.0 

319 

0.87 

6.10 

1.70 

34.0 

131 

214 

184 

29.9 

25.8 

48.9 

31.0 

6.3 

1.69 

7.9 

0.88 

3.31 

0.50 

n.a. 

n.a. 

54.35 

14.33 

10.87 

4.62 

9.04 

2.94 

1.38 

1.76 

0.31 

0.20 

99.80 

533 

410 

43.9 

56.2 

0.86 

3.83 

24 

30.7 

36.0 

345 

0.79 

3.66 

n.a. 

28.0 

130 

n.a. 

160 

36.4 

19.8 

40.2 

23.0 

5.8 

1.76 

n.a. 

0.99 

2.73 

0.51 

n.a. 

n.a. 

53.29 

14.56 

10.89 

5.44 

9.70 

2.82 

1.01 

1.64 

0.24 

0.19 

99.78 

413 

414 

39.5 

129.6 

0.68 

3.38 

12 

22.7 

25.5 

317 

0.64 

3.10 

0.82 

29.5 

128 

116 

137 

37.9 

16.8 

33.7 

19.0 

4.9 

1.51 

4.5 

0.88 

2.67 

0.45 

n.a. 

n.a. 

53.75 

14.54 

11.27 

5.12 

8.68 

3.08 

1.13 

1.72 

0.27 

0.18 

99.74 

485 

474 

38.8 

52.7 

0.66 

3.58 

14.3 

28.7 

30.0 

354 

0.72 

3.16 

0.79 

32.0 

125 

165 

148 

36.0 

18.7 

37.0 

22.3 

5.5 

1.58 

20.4 

0.85 

3.10 

0.45 

n.a. 

n.a. 

52.69 56.80 55.89 56.21 56.20 56.22 56.60 55.00 55.55 56.37 54.46 53.41 53.89 

14.74 13.59 13.84 14.10 13.96 13.53 14.01 13.40 13.83 14.16 14.36 14.59 14.58 

11.50 11.03 12.01 11.19 11.66 11.69 11.20 12.95 12.16 10.95 10.89 10.91 11.30 

5.54 3.44 3.76 3.68 3.73 3.72 3.63 3.62 3.42 3.74 4.63 5.45 5.13 

9.81 7.08 7.24 7.26 6.98 7.35 7.11 6.96 7.03 7.17 9.06 9.72 8.70 

2.93 3.01 2.93 3.03 3.24 2.91 3.32 3.37 3.16 3.03 2.95 2.83 3.09 

0.75 2.16 1.82 2.04 1.71 1.95 1.75 1.70 1.99 2.21 1.38 1.01 1.13 

1.57 2.28 1.97 1.96 1.98 2.13 1.92 2.39 2.28 1.88 1.76 1.64 1.72 

0.29 0.41 0.34 0.34 0.35 0.31 0.28 0.42 0.38 0.32 0.31 0.24 0.27 

0.18 0.20 0.19 0.19 0.18 0.20 0.18 0.20 0.20 0.18 0.20 0.19 0.18 

100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 

Tables and Figures 25 
Table 3. Average chemical composition of geochemical units in the Grande Ronde Basalt-Continued 

Geochemical 

unit-------- 3D SD SD UNC 2D 2D 2D 2D 2D 2D 2D 2D 2D* 

Chemical type - c E E X B B B B B B B B B 

Si02 

Al2o3 

FeO 

MgO 

CaO 

Na20 

K2o 

Ti02 

P205 

MnO 

Total 

Ba 

BaX 

Co 

Cr 

Cs 

Hf 

NbX 

Rb 

RbX 

SrX 

Ta 

Th 

u 

YX 

Zn 

Zr 

ZrX 

Sc 

La 

Ce 

Nd 

Sm 

Eu 

Gd 

Tb 

Yb 

Lu 

Cu 

Ni 

Si02 

Al203 

FeO 

MgO 

CaO 

Na20 

K20 

Ti02 

P205 

MnO 

Total 

26 

53.43 

14.60 

11.22 

5.25 

9.10 

2.89 

1.11 

1.72 

0.26 

0.19 

99.77 

495 

485 

41.1 

100.0 

0.71 

3.72 

13.3 

27.7 

36.3 

308 

0.74 

3.46 

1.02 

33.3 

131 

120 

164 

37.1 

18.3 

37.5 

20.5 

5.3 

1.66 

5.0 

0.96 

2.72 

0.50 

41.0 

16.0 

54.90 

14.04 

11.98 

4.16 

7.79 

2.82 

1.66 

1.96 

0.29 

0.18 

99.78 

644 

n.a. 

41.5 

19.1 

1.29 

4.30 

n.a. 

41.0 

n.a. 

n.a. 

0.9 

4.82 

n.a. 

n.a. 

141 

n.a. 

n.a. 

34.2 

22.9 

44.8 

26.2 

6.0 

1.90 

n.a. 

1.17 

2.96 

0.54 

n.a. 

n.a. 

55.17 

14.01 

11.52 

4.37 

7.74 

3.09 

1.54 

1.87 

0.28 

0.19 

99.78 

632 

n.a. 

41.9 

22.3 

0.82 

4.17 

n.a. 

41.3 

n.a. 

n.a. 

0.95 

4.99 

n.a. 

n.a. 

128 

n.a. 

n.a. 

33.0 

21.6 

42.6 

21.8 

5.9 

1.77 

n.a. 

1.04 

2.79 

0.50 

n.a. 

n.a. 

54.97 

13.46 

12.33 

3.81 

7.45 

3.03 

1.73 

2.30 

0.50 

0.20 

99.78 

Major oxides (weight percent) 

54.45 

13.93 

12.43 

3.89 

7.60 

3.10 

1.65 

2.13 

0.39 

0.21 

99.78 

54.65 

14.18 

12.04 

3.79 

7.48 

3.18 

1.73 

2.12 

0.37 

0.19 

99.73 

54.22 

14.12 

12.81 

3.66 

7.03 

3.27 

1.68 

2.25 

0.43 

0.20 

99.67 

54.71 

14.09 

12.03 

3.55 

7.29 

2.95 

2.10 

2.43 

0.44 

0.20 

99.79 

Trace elements (parts per million) 

727 

n.a. 

41.1 

9.2 

1.08 

4.79 

n.a. 

39.5 

n.a. 

n.a. 

0.99 

5.33 

n.a. 

n.a. 

150 

n.a. 

n.a. 

33.5 

26.2 

54.0 

29.8 

7.3 

2.13 

n.a. 

1.07 

3.37 

0.63 

n.a. 

n.a. 

692 

645 

43.4 

14.0 

1.12 

4.82 

16.0 

37.5 

48.0 

313 

0.85 

4.58 

n.a. 

40.0 

151 

n.a. 

194 

35.8 

25.1 

51.3 

30.3 

7.1 

2.11 

n.a. 

1.42 

3.41 

0.62 

62.0 

17.0 

630 

649 

38.0 

8.3 

0.65 

4.48 

13.0 

50.0 

41.0 

312 

0.91 

5.0 

1.27 

32.0 

149 

159 

176 

32.6 

24.0 

46.2 

27.0 

6.5 

1.83 

6.6 

0.93 

3.54 

0.53 

n.a. 

n.a. 

693 

683 

38.6 

10.3 

1.01 

4.67 

10.0 

36.4 

29.0 

322 

0.95 

4.96 

1.44 

32.0 

139 

151 

183 

32.6 

25.9 

53.1 

28.8 

7.0 

2.05 

6.6 

1.05 

3.56 

0.58 

n.a. 

n.a. 

701 

n.a. 

40.2 

13.5 

1.28 

5.14 

n.a. 

57.5 

n.a. 

n.a. 

1.02 

5.33 

n.a. 

n.a. 

147 

n.a. 

n.a. 

33.4 

27.6 

58.7 

32.7 

7.8 

2.34 

n.a. 

1.35 

3.65 

0.61 

n.a. 

n.a. 

56.07 

13.61 

11.66 

3.23 

6.78 

2.99 

2.39 

2.31 

0.52 

0.22 

99.78 

824 

827 

38.4 

9.4 

1.54 

4.91 

12.0 

69.2 

66.0 

321 

0.91 

7.34 

n.a. 

34.0 

137 

n.a. 

198 

29.3 

28.9 

57.5 

37.1 

8.0 

2.08 

n.a. 

1.22 

3.40 

0.55 

18.0 

6.0 

Normalized major-oxide contents (weight percent) 

54.01 

13.93 

12.68 

3.80 

7.24 

3.16 

1.84 

2.46 

0.44 

0.20 

99.76 

714 

706 

38.7 

14.5 

1.14 

4.99 

12.0 

46.3 

46.0 

312 

0.88 

5.16 

1.18 

33.0 

147 

198 

194 

32.5 

26.0 

54.6 

31.7 

7.3 

2.02 

7.0 

1.21 

3.54 

0.59 

n.a. 

n.a. 

55.44 

13.85 

11.95 

3.46 

6.97 

3.11 

2.01 

2.33 

0.46 

0.21 

99.79 

802 

619 

37.1 

11.7 

1.50 

5.27 

14.0 

48.6 

54.0 

340 

0.95 

5.96 

n.a. 

33.0 

147 

n.a. 

231 

31.0 

28.7 

58.5 

33.5 

7.8 

2.19 

n.a. 

1.2 

3.67 

0.63 

n.a. 

n.a. 

55.56 

13.75 

11.82 

3.50 

7.09 

3.19 

2.01 

2.22 

0.43 

0.20 

99.77 

730 

715 

34.6 

12.5 

1.32 

4.74 

13.0 

45.4 

51.0 

359 

0.90 

6.38 

1.78 

37.0 

140 

178 

183 

31.0 

27.6 

54.2 

29.9 

7.3 

2.06 

7.0 

1.08 

3.13 

0.55 

n.a. 

n.a. 

55.39 

13.95 

11.92 

3.54 

7.09 

3.15 

1.87 

2.31 

0.37 

0.18 

99.77 

685 

746 

35.9 

7.9 

1.38 

4.88 

14.0 

55.0 

52.0 

324 

0.92 

6.50 

1.63 

35.0 

145 

157 

191 

30.5 

27.9 

56.0 

28.0 

7.3 

1.92 

6.2 

1.20 

3.40 

0.52 

n.a. 

n.a. 

53.55 55.02 55.29 55.09 54.57 54.80 54.40 54.83 56.19 54.14 "55.56 55.69 55.52 

14.63 14.07 14.04 13.49 13.96 14.22 14.17 14.12 13.64 13.96 13.88 13.78 13.98 

11.25 12.01 11.55 12.36 12.46 12.07 12.85 12.06 11.69 12.71 11.98 11.85 11.95 

5.26 4.17 4.38 3.82 3.90 3.80 3.67 3.56 3.24 3.81 3.47 3.51 3.55 

9.12 7.81 7.76 7.47 7.62 7.50 7.05 7.31 6.79 7.26 6.98 7.11 7.11 

2.90 2.83 3.10 3.04 3.11 3.19 3.28 2.96 3.00 3.17 3.12 3.20 3.16 

1.11 1.66 1.54 1.73 1.65 1.73 1.69 2.10 2.40 1.84 2.01 2.01 1.87 

1.72 1.96 1.87 2.31 2.13 2.13 2.26 2.44 2.32 2.47 2.33 2.23 2.32 

0.26 0.29 0.28 0.50 0.39 0.37 0.43 0.44 0.52 0.44 0.46 0.43 0.37 

0.19 0.18 0.19 0.20 0.21 0.19 0.20 0.20 0.22 0.20 0.21 0.20 0.18 

100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 

Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
Table 3. Average chemical composition of geochemical units in the Grande Ronde Basalt-Continued 

Geochemical 

unit-------- 2D* 

Chemical type - B 

Si02 

Al203 

FeO 

MgO 

CaO 

Na20 

K20 

Ti02 

P205 

MnO 

Total 

Ba 

BaX 

Co 

Cr 

Cs 

Hf 

NbX 

Rb 

RbX 

SrX 

Ta 

Th 

u 

Zn "'

Zr 

ZrX 

Sc 

La 

Ce 

Nd 

Sm 

Eu 

Gd 

Tb 

Yb 

Lu 

Cu 

Ni 

55.25 

13.93 

12.02 

3.60 

7.11 

3.28 

1.76 

2.24 

0.35 

0.18 

99.72 

689 

700 

35.3 

10.7 

1.40 

4.71 

14.5 

49.0 

53.5 

332 

0.84 

6.05 

1.50 

36.0 

137 

179 

190 

31.3 

26.3 

50.3 

27.5 

6.6 

1. 86 

6.3 

1.00 

3.42 

0.52 

n.a. 

n.a. 

55.41 

13.97 

12.05 

3.61 

7.13 

3.29 

1.76 

2.25 

0.35 

2D* 

B 

55.08 

13.89 

12.24 

3.50 

6.99 

3.39 

1.82 

2.30 

0.37 

0.19 

99.77 

755 

710 

33.3 

7.9 

1.50 

5.20 

16.0 

51.0 

49.0 

337 

0.96 

5.80 

1.45 

39.0 

14 6 

195 

207 

30.8 

27.9 

56.0 

31.0 

7.3 

2.09 

8.2 

1.08 

3.94 

0.59 

n.a. 

n.a. 

55.21 

13.92 

12.27 

3.51 

7.01 

3.40 

1.82 

2.31 

0.37 

2D 

B 

55.81 

14.20 

11.76 

3.40 

6.95 

3.01 

1.91 

2.16 

0.39 

0.18 

99.77 

730 

n.a. 

36.3 

11.8 

1.37 

4.93 

n.a. 

41.2 

n.a. 

n.a. 

0.90 

6.80 

n.a. 

n.a. 

146 

n.a. 

n.a. 

31.9 

27.7 

58.1 

32.5 

7.6 

2.17 

n.a. 

1.23 

3.58 

0.55 

n.a. 

n.a. 

2D 

B 

56.27 

14.12 

11.43 

3.50 

6.44 

3.32 

1.91 

2.23 

0.41 

0.17 

99.80 

UNC AS16 AS16 AS16 

X 

Major oxides (weight percent) 

56.04 

14.10 

10.26 

3.76 

7.59 

3.07 

2.04 

2.14 

0.43 

0.21 

99.64 

54.15 

13.70 

12.26 

4.59 

8.19 

2.96 

1.43 

2.00 

0.32 

0.20 

99.80 

54.09 

14.27 

11.95 

4.48 

8.26 

2.90 

1.34 

2.00 

0.30 

0.19 

99.78 

53.83 

14.08 

12.44 

4.40 

7.99 

3.09 

1.33 

2.09 

0.33 

0.20 

99.78 

Trace elements (parts per million) 

722 

614 

40.7 

17.3 

1.10 

4.77 

13.0 

38.2 

50.0 

380 

0.84 

6.71 

n.a. 

38.0 

137 

n.a. 

201 

31.3 

27.3 

55.8 

32.1 

7.3 

2.15 

n.a. 

1.21 

3.1 

0.53 

n.a. 

n.a. 

844 

873 

35.7 

10.6 

1.34 

4.86 

14.0 

61.0 

57.0 

330 

0.88 

6.50 

1.50 

35.0 

138 

125 

191 

30.2 

27.6 

54.0 

30.0 

7.0 

1.94 

6.0 

1.02 

3.47 

0.51 

n.a. 

n.a. 

491 

n.a. 

42.2 

23.4 

1.80 

3.94 

n.a. 

28.9 

n.a. 

n.a. 

0.68 

3.84 

n.a. 

n.a. 

136 

n.a. 

n.a. 

35.0 

18.6 

38.9 

23.0 

6.2 

1.71 

n.a. 

1.07 

2.83 

0.51 

n.a. 

n.a. 

504 

n.a. 

42.7 

19.8 

1.13 

3.98 

n.a. 

33.8 

n.a. 

n.a. 

0.73 

3.77 

n.a. 

n.a. 

138 

n.a. 

n.a. 

36.0 

18.7 

38.8 

23.9 

6.1 

1.77 

n.a. 

1.18 

3.10 

0.53 

n.a. 

n.a. 

609 

n.a. 

41.9 

19.3 

0.94 

4.08 

n.a. 

43.9 

n.a. 

n.a. 

0.67 

3.96 

n.a. 

n.a. 

143 

n.a. 

n.a. 

35.7 

19.1 

41.7 

26.8 

6.2 

1.90 

n.a. 

1.25 

3.29 

0.54 

n.a. 

n.a. 

AS16 

54.56 

13.71 

12.03 

4.49 

8.01 

3.19 

1.19 

2.06 

0.35 

0.21 

99.80 

549 

n.a. 

42.4 

21.9 

n.a. 

4.14 

n.a. 

23.5 

n.a. 

n.a. 

0.74 

3.73 

n.a. 

n.a. 

145 

n.a. 

n.a. 

35.2 

19.1 

39.1 

23.2 

6.1 

1.75 

n.a. 

1.00 

2.94 

0.55 

n.a. 

n.a. 

Normalized major-oxide contents (weight percent) 

55.94 

14.23 

11.79 

3.41 

6.97 

3.02 

1.91 

2.16 

0.39 

56.38 

14.15 

11.45 

3.51 

6.45 

3.33 

1.91 

2.23 

0.41 

56.24 

14.15 

10.30 

3.77 

7.62 

3.08 

2.05 

2.15 

0.43 

54.26 

13.73 

12.28 

4.60 

8.21 

2.97 

1.43 

2.00 

0.32 

54.21 

14.30 

11.98 

4.49 

8.28 

2.91 

1.34 

2.00 

0.30 

53.95 

14.11 

12.47 

4.41 

8.01 

3.10 

1.33 

2.09 

0.33 

54.67 

13.74 

12.05 

4.50 

8.03 

3.20 

1.19 

2.06 

0.35 

KBS 

53.66 

13.77 

12.86 

4.13 

7.82 

3.15 

1.50 

2.24 

0.43 

0.22 

99.78 

585 

597 

39.6 

22.5 

1.12 

4.27 

12.0 

30.8 

40.5 

342 

0.83 

3.95 

n.a. 

36.0 

14 6 

n.a. 

177 

35.9 

21.3 

44.6 

26.6 

6.6 

1.99 

n.a. 

1.19 

3.35 

0.58 

27.0 

10.5 

53.78 

13.80 

12.89 

4.14 

7.84 

3.16 

1.50 

2.24 

0.43 

KBS 

53.56 

14.17 

12.64 

4.16 

7.79 

3.11 

1.52 

2.21 

0.41 

0.21 

99.78 

530 

n.a. 

40.7 

22.6 

1.18 

4.14 

n.a. 

39.5 

n.a. 

n.a. 

0.83 

4.33 

n.a. 

n.a. 

146 

n.a. 

n.a. 

36.5 

20.6 

43.0 

25.8 

6.8 

1.99 

n.a. 

1.10 

3.52 

0.59 

n.a. 

n.a. 

53.68 

14.20 

12.67 

4.17 

7.81 

3.12 

1.52 

2.21 

0.41 

3E 

c 

54.67 

14.13 

11.26 

5.05 

8.14 

3.28 

1.16 

1.71 

0.25 

0.16 

99.81 

427 

n.a. 

39.6 

25.5 

0.95 

3.65 

n.a. 

n.a. 

n.a. 

n.a. 

0.62 

3.84 

n.a. 

n.a. 

122 

n.a. 

n.a. 

34.2 

16.5 

34.2 

21.3 

5.4 

1.65 

n.a. 

1.14 

2.59 

0.44 

n.a. 

n.a. 

54.77 

14.16 

11.28 

5.06 

8.16 

3.29 

1.16 

1.71 

0.25 

3E 

c 

53.96 

14.42 

11.17 

5.16 

8.79 

3.07 

1.15 

1.66 

0.24 

0.19 

99.81 

480 

346 

39.8 

24.2 

0.97 

3.59 

11.0 

25.8 

30.0 

298 

0.72 

3.48 

n.a. 

31.0 

129 

n.a. 

145 

34.6 

16.7 

36.5 

20.50 

5.3 

1.66 

n.a. 

O.S5 

2.41 

0.48 

n.a. 

n.a. 

54.06 

14.45 

11.19 

5.17 

8.81 

3.08 

1.15 

1.66 

0.24 

Si02 

Al203 

FeO 

MgO 

CaO 

Na20 

K20 

Ti02 

P205 

MnO 0.18 0.19 0.18 0.17 0.21 0.20 0.19 0.20 0.21 0.22 0.21 0.16 0.19 

Total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 

Tables and Figures 27 
Table 3. Average chemical composition of geochemical units in the Grande Ronde Basalt-Continued 

Geochemical 

unit-------- AS16 3F SE AS16 AS16 AS16 AS16 3G 3G SF SF AS16 AS16 

Chemical type - 4 c E c c E E 

Si02 

Al203 

FeO 

MgO 

CaO 

Na20 

K20 

Ti02 

P205 

MnO 

Total 

Ba 

BaX 

Co 

Cr 

Cs 

Hf 

NbX 

Rb 

RbX 

SrX 

Ta 

Th 

u 

)X 

Zn 

Zr 

ZrX 

Sc 

La 

Ce 

Nd 

Sm 

Eu 

Gd 

Tb 

Yb 

Lu 

Cu 

Ni 

Si02 

AI203 

FeO 

MgO 

CaO 

Na20 

K20 

Ti02 

P205 

MnO 

Total 

28 

53.90 

13.97 

12.52 

4.27 

7.89 

3.13 

1.54 

1.95 

0.41 

0.21 

99.79 

574 

n.a. 

38.7 

16.3 

1.01 

4.22 

n.a. 

30.1 

n.a. 

n.a. 

0.74 

3.82 

0.0 

0.0 

152 

0 

n.a. 

36.5 

21.1 

44.6 

26.3 

6.6 

2.00 

n.a. 

1.03 

3.26 

0.62 

n.a. 

n.a. 

54.21 

14.59 

11.01 

4.99 

8.84 

2.94 

1.12 

1.67 

0.25 

0.18 

99.80 

497 

528 

39.1 

22.9 

1.00 

3.61 

8.0 

26.8 

29.0 

346 

0.68 

3.58 

n.a. 

35.0 

132 

n.a. 

154 

35.2 

17.4 

36.8 

20.7 

5.4 

1.64 

n.a. 

0.96 

2.51 

0.48 

37.0 

16.0 

54.46 

14.43 

11.53 

4.49 

8.14 

2.99 

1.45 

1.79 

0.30 

0.20 

99.78 

542 

n.a. 

40.0 

17.2 

1.08 

4.10 

n.a. 

35.4 

n.a. 

n.a. 

0.69 

3.72 

n.a. 

n.a. 

135 

n.a. 

n.a. 

35.8 

19.5 

40.8 

24.1 

6.1 

1.84 

n.a. 

1.04 

3.15 

0.54 

n.a. 

n.a. 

54.39 

14.41 

11.64 

4.23 

8.13 

3.12 

1.39 

1.94 

0.34 

0.20 

99.79 

Major oxides (weight percent) 

54.30 

14.05 

12.15 

3.94 

7.77 

3.08 

1.72 

2.18 

0.40 

0.20 

99.79 

53.97 

14.03 

12.43 

4.43 

7.71 

3.26 

1.38 

2.01 

0.39 

0.19 

99.80 

54.43 

14.17 

12.62 

4.07 

7.27 

3.22 

1.40 

2.05 

0.34 

0.20 

99.77 

55.01 

14.87 

10.11 

4.72 

8.59 

3.12 

1.19 

1.73 

0.29 

0.19 

99.82 

Trace elements (parts per million) 

550 

n.a. 

38.4 

16.3 

0.90 

4.00 

n.a. 

33.9 

n.a. 

n.a. 

0.83 

4.19 

n.a. 

n.a. 

134 

n.a. 

n.a. 

34.9 

20.7 

42.5 

24.9 

5.9 

1.82 

n.a. 

0.97 

2.99 

0.52 

n.a. 

n.a. 

566 

614 

38.7 

21.6 

1.35 

4.15 

12.0 

36.6 

41.0 

333 

0.70 

4.59 

n.a. 

33.0 

144 

n.a. 

179 

35.5 

22.2 

46.2 

25.5 

6.2 

1.97 

n.a. 

1.02 

2.95 

0.53 

25.0 

10.0 

607 

n.a. 

39.3 

14.5 

0.90 

4.23 

n.a. 

37.6 

n.a. 

n.a. 

0.72 

4.22 

n.a. 

n.a. 

137 

n.a. 

n.a. 

35.5 

20.2 

41.2 

21.2 

5.8 

1.88 

n.a. 

1.02 

3.03 

0.59 

n.a. 

n.a. 

636 

n.a. 

39.5 

13.7 

1.18 

4.45 

n.a. 

56.4 

n.a. 

n.a. 

0.81 

4.49 

n.a. 

n.a. 

140 

n.a. 

n.a. 

34.5 

21.3 

44.8 

26.8 

6.9 

2.04 

n.a. 

1.17 

3.25 

0.58 

n.a. 

n.a. 

611 

n.a. 

36.4 

24.0 

0.85 

3.89 

n.a. 

23.1 

n.a. 

n.a. 

0.71 

3.95 

n.a. 

n.a. 

142 

n.a. 

n.a. 

35.6 

19.0 

40.3 

24.1 

5.7 

1.74 

n.a. 

0.98 

2.84 

0.54 

n.a. 

n.a. 

54.41 

14.50 

11.21 

4.79 

8.53 

2.94 

1.25 

1.70 

0.26 

0.19 

99.78 

479 

n.a. 

38.9 

30.6 

1.08 

3.76 

n.a. 

39.8 

n.a. 

n.a. 

0.64 

3.49 

n.a. 

n.a. 

132 

n.a. 

n.a. 

34.7 

18.1 

36.8 

21.2 

5.3 

1.68 

n.a. 

0.94 

2.63 

0.49 

n.a. 

n.a. 

Normalized major-oxide contents (weight percent) 

55.68 

14.38 

11.01 

3.93 

7.56 

3.22 

1.57 

1.95 

0.30 

0.19 

99.79 

676 

647 

39.5 

10.0 

1.19 

4.74 

12.0 

37.7 

38.0 

324 

0.84 

4.53 

n.a. 

35.0 

147 

n.a. 

197 

33.2 

21.3 

45.8 

25.9 

6.7 

2.06 

n.a. 

1.12 

3.23 

0.57 

32.5 

12.0 

55.40 

13.81 

12.02 

3.77 

7.22 

3.43 

1.57 

2.04 

0.34 

0.18 

99.78 

547 

n.a. 

38.5 

5.3 

0.80 

4.95 

n.a. 

47.9 

n.a. 

n.a. 

0.82 

3.96 

n.a. 

n.a. 

134 

n.a. 

n.a. 

32.6 

22.3 

45.9 

26.0 

6.5 

1.99 

n.a. 

1.08 

3.19 

0.57 

n.a. 

n.a. 

54.35 

13.93 

12.48 

4.05 

7.51 

3.51 

1.43 

1.98 

0.33 

0.22 

99.79 

543 

564 

39.5 

13.8 

1.41 

4.25 

13.0 

40.5 

39.0 

306 

0.64 

3.78 

n.a. 

33.0 

127 

n.a. 

178 

32.8 

20.1 

42.0 

24.2 

6.0 

1.91 

n.a. 

1.19 

3.02 

0.57 

52.0 

10.0 

54.47 

14.27 

11.83 

4.29 

7.93 

3.30 

1.29 

1.93 

0.27 

0.20 

99.78 

543 

n.a. 

38.4 

13.5 

0.70 

4.22 

n.a. 

21.4 

n.a. 

n.a. 

0.78 

3.87 

n.a. 

n.a. 

146.00 

n.a. 

n.a. 

32.8 

19.2 

39.3 

22.1 

5.8 

1.75 

n.a. 

1.24 

2.92 

0.50 

n.a. 

n.a. 

54.01 54.32 54.58 54.50 54.41 54.08 54.56 55.11 54.53 55.80 55.52 54.46 54.59 

14.00 14.62 14.46 14.44 14.08 14.06 14.20 14.90 14.53 14.41 13.84 13.96 14.30 

12.55 11.03 11.56 11.66 12.18 12.45 12.65 10.13 11.23 11.03 12.05 12.51 11.86 

4.28 5.00 4.50 4.24 3.95 4.44 4.08 4.73 4.80 3.94 3.78 4.06 4.30 

7.91 8.86 8.16 8.15 7.79 7.73 7.29 8.61 8.55 7.58 7.24 7.53 7.95 

3.14 2.95 3.00 3.13 3.09 3.27 3.23 3.13 2.95 3.23 3.44 3.52 3.31 

1.54 1.12 1.45 1.39 1.72 1.38 1.40 1.19 1.25 1.57 1.57 1.43 1.29 

1.95 1.67 1.79 1.94 2.18 2.01 2.05 1.73 1.70 1.95 2.04 1.98 1.93 

0.41 0.25 0.30 0.34 0.40 0.39 0.34 0.29 0.26 0.30 0.34 0.33 0.27 

0.21 0.18 0.20 0.20 0.20 0.19 0.20 0.19 0.19 0.19 0.18 0.22 0.20 

100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 

Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
Table 3. Average chemical composition of geochemical units in the Grande Ronde Basalt-Continued 

Geochemical 

unit-------- AS16 

Chemical type - 4 

AS16 

4 

Si02 

A12o3 

FeO 

MgO 

CaO 

Na20 

K2o 

Ti02 

P2o5 

MnO 

Total 

Ba 

BaX 

Co 

Cr 

Cs 

Hf 

NbX 

Rb 

RbX 

SrX 

Ta 

Th 

u 

YX 

Zn 

Zr 

ZrX 

Sc 

La 

Ce 

Nd 

Sm 

Eu 

Gd 

Tb 

Yb 

Lu 

Cu 

Ni 

Si02 

A12o3 

FeO 

MgO 

CaO 

Na20 

K2o 

no2 

P205 

MnO 

Total 

54.15 

14.00 

12.46 

4.07 

7.88 

3.04 

1.57 

2.07 

0.36 

0.20 

99.80 

536 

n.a. 

37.9 

10.9 

1.31 

4.55 

n.a. 

47.8 

n.a. 

n.a. 

0.69 

3.83 

0.0 

n.a. 

132 

n.a. 

n.a. 

33.7 

21.1 

44.5 

26.9 

6.4 

1.97 

n.a. 

1.01 

3.06 

0.58 

n.a. 

n.a. 

53.75 

14.55 

12.61 

4.40 

7.98 

2.88 

1.06 

2.11 

0.26 

0.18 

99.78 

496 

n.a. 

39.5 

13.0 

1.12 

4.67 

n.a. 

25.5 

n.a. 

n.a. 

0.93 

4.73 

n.a. 

n.a. 

137 

n.a. 

n.a. 

33.3 

21.1 

44.0 

26.5 

6.7 

1.96 

n.a. 

0.98 

3.04 

0.56 

n.a. 

n.a. 

54.26 53.87 

14.03 14.58 

12.48 12.64 

4.08 4.41 

7.90 8.00 

3.05 2.89 

1.57 1.06 

2.07 2.11 

0.36 0.26 

0.20 0.18 

100.00 100.00 

SH 

E 

55.24 

14.21 

11.50 

4.00 

7.66 

3.03 

1.67 

1.99 

0.29 

0.19 

99.78 

642 

n.a. 

40.3 

12.3 

1.30 

4.62 

n.a. 

52.4 

n.a. 

n.a. 

0.90 

4.71 

n.a. 

n.a. 

128 

n.a. 

n.a. 

32.7 

21.7 

45.5 

27.7 

6.6 

1.87 

n.a. 

1.16 

3.09 

0.52 

n.a. 

n.a. 

AS16 

54.54 

14.54 

11.60 

4.24 

7.83 

3.13 

1.52 

1.93 

0.29 

0.19 

99.81 

UNC 

X 

AS16 AS16 

4 

2F 

B 

Major oxides (weight percent) 

56.66 

13.88 

11.67 

3.12 

6.65 

3.18 

1.99 

2.14 

0.32 

0.18 

99.79 

56.60 

13.52 

11.87 

3.32 

6.88 

3.09 

1.94 

2.09 

0.30 

0.19 

99.80 

54.60 

14.67 

11.61 

4.20 

7.71 

3.09 

1.44 

1.99 

0.32 

0.18 

99.81 

54.74 

13.61 

12.86 

3.82 

7.29 

3.17 

1.54 

2.16 

0.37 

0.23 

99.79 

Trace elements (parts per million) 

639 

n.a. 

38.3 

14.6 

1.20 

4.43 

n.a. 

30.8 

n.a. 

n.a. 

0.83 

4.39 

n.a. 

n.a. 

146 

n.a. 

n.a. 

34.0 

20.3 

41.9 

25.3 

6.4 

1.91 

n.a. 

1.03 

3.19 

0.57 

n.a. 

n.a. 

710 

634 

37.0 

9.0 

1.86 

5.22 

15.5 

53.0 

64.0 

337 

0.95 

5.81 

n.a. 

40.0 

145 

n.a. 

217 

30.1 

24.8 

52.4 

31.6 

7.2 

1.98 

n.a. 

1.16 

3.39 

0.59 

19.0 

10.0 

641 

681 

36.5 

10.2 

1.44 

5.05 

15.0 

49.2 

54.0 

327 

0.90 

5.54 

n.a. 

35.0 

135 

n.a. 

206 

30.6 

23.3 

48.6 

29.0 

6.7 

2.00 

n.a. 

1.15 

3.19 

0.56 

21.0 

10.0 

597 

n.a. 

38.5 

16.7 

1.46 

4.80 

n.a. 

34.9 

n.a. 

n.a. 

0.77 

4.87 

n.a. 

n.a. 

147 

n.a. 

n.a. 

31.5 

23.1 

48.7 

27.4 

7.0 

1.95 

n.a. 

1.11 

3.07 

0.54 

n.a. 

n.a. 

557 

583 

38.5 

17.2 

0.80 

4.94 

16.0 

50.1 

42.0 

305 

0.85 

4.30 

n.a. 

39.0 

137 

n.a. 

200 

33.1 

22.1 

47.4 

30.6 

6.9 

2.11 

n.a. 

1.21 

3.45 

0.57 

42.0 

14.0 

2F 

B 

54.68 

13.58 

12.81 

3.62 

7.13 

3.46 

1.58 

2.27 

0.44 

0.20 

99.77 

644 

n.a. 

38.8 

14.5 

1.22 

5.33 

n.a. 

39.6 

n.a. 

n.a. 

0.81 

4.49 

n.a. 

n.a. 

143 

n.a. 

n.a. 

33.2 

23.7 

51.6 

34.7 

7.5 

2.26 

n.a. 

1.23 

3.84 

0.63 

n.a. 

n.a. 

Normalized major-oxide contents (weight percent) 

55.36 

14.24 

11.53 

4.01 

7.68 

3.04 

1.67 

1.99 

0.29 

0.19 

100.00 

54.64 

14.57 

11.62 

4.25 

7.84 

3.14 

1.52 

1.93 

0.29 

0.19 

100.00 

56.78 56.71 

13.91 13.55 

11.69 11.89 

3.13 3.33 

6.66 6.89 

3.19 3.10 

1.99 1.94 

2.14 2.09 

0.32 0.30 

0.18 0.19 

100.00 100.00 

54.70 

14.70 

11.63 

4.21 

7.72 

3.10 

1.44 

1.99 

0.32 

0.18 

100.00 

54.86 

13.64 

12.89 

3.83 

7.31 

3.18 

1.54 

2.16 

0.37 

0.23 

100.00 

54.81 

13.61 

12.84 

3.63 

7.15 

3.47 

1.58 

2.28 

0.44 

0.20 

100.00 

SI 

E 

55.82 

14.02 

11.33 

3.96 

7.49 

3.09 

1.61 

2.00 

0.31 

0.19 

99.82 

574 

n.a. 

39.0 

11.3 

1.33 

4.82 

n.a. 

47.2 

n.a. 

n.a. 

0.87 

5.26 

n.a. 

n.a. 

117 

n.a. 

n.a. 

31.0 

22.2 

46.5 

26.6 

6.4 

1.87 

n.a. 

1.00 

2.87 

0.51 

n.a. 

n.a. 

55.92 

14.05 

11.35 

3.97 

7.50 

3.10 

1.61 

2.00 

0.31 

0.19 

100.00 

AS16 

4 

54.21 

13.75 

12.13 

4.39 

8.34 

2.85 

1.44 

2.15 

0.34 

0.20 

99.80 

534 

n.a. 

40.5 

35.3 

1.57 

4.64 

n.a. 

40.4 

n.a. 

n.a. 

0.88 

3.79 

n.a. 

n.a. 

125 

n.a. 

n.a. 

34.1 

21.2 

46.1 

26.7 

6.7 

1.96 

n.a. 

1.17 

3.40 

0.55 

n.a. 

n.a. 

54.32 

13.78 

12.15 

4.40 

8.36 

2.86 

1.44 

2.15 

0.34 

0.20 

100.00 

Tables and Figures 29 
Table 4. Average chemical composition of geochemical units in the Wanapum Basalt 

[Chemical types listed in approximate stratigraphic order, see table 1. Trace elements followed by X analyzed by X-ray 

fluorescence; all others analyzed by instrumental neutron activation. n.a., not analyzed; Data from which these average 

compositions are calculated are given in Wright (1988)] 

Geochemical 

unit-------- PV LOLO INC ROSALIA PH POWAT ROZA FS ANOM FS INC SHUMAKER PH SHUM SW LOOK DODGE ROBIN 

Chemical type- A B c D E F F G G H J 

Major oxides (weight percent) 

Si02 51.27 49.98 49.78 53.82 50.74 52.68 51.51 54.36 54.29 54.48 52.15 49.78 

Al203 15.41 14.13 13.39 14.59 14.21 13.94 13.43 13.86 14.38 14.66 15.41 16.78 

FeO 10.23 13.89 14.73 12.93 13.45 11.16 14.30 13.42 13.46 13.28 10.73 10.13 

MgO 3. 75 5.15 4.48 3.23 4.55 4.29 4.42 2.89 2.97 2.91 5.89 8.19 

CaO 10.42 8.80 8.64 7.00 8.53 8.68 8.05 6.39 6.55 6.54 9.86 10.80 

Na20 3.13 2.58 2.79 3.03 2.84 2.86 2.73 3.23 3.41 3.05 2.90 2.42 

K20 1.18 1.05 1.21 1.93 1.25 1.38 1.35 1.87 1. 81 1.96 0.68 0.37 

Ti02 3.50 3.22 3.59 2.67 3.11 3.52 3.01 2.45 2.47 2.71 1.45 0.97 

P205 0.79 0.73 0.84 1.15 0.68 0. 71 0.61 0.90 0.89 0.75 0.36 0.17 

MnO 0.15 0.19 0.20 0.24 0.25 0.23 0.22 0.30 0.26 0.22 0.15 0.14 

Total 99.83 99.72 99.65 100.59 99.61 99.45 99.63 99.67 100.49 100.56 99.58 99.75 

Trace elements (parts per million) 

Ba 677 539 600 1043 556 812 549 991 1024 762 348 175 

BaX 650 481 524 955 572 807 457 1001 972 761 327 135 

Co 28.8 40.2 37.7 n.a. 38.5 52.9 38.8 23.9 n.a. n.a. 36.9 46.6 

Cr 102.9 82 13.6 n.a. 44.3 24.4 39.5 4.4 4.9 6.8 159.7 151.4 

Cs 0.62 0.70 0.89 1.15 0.78 0.95 0.93 1.02 0.86 1.21 0.50 n.a. 

Hf 5.02 4.66 5.43 6.40 4.64 5.08 4.42 6.16 6.33 5.63 2.86 1.48 

NbX 19.0 15.8 17.0 20.0 17.0 17.5 13.0 19.3 24.0 18.5 8.7 6.0 

Rb 28.2 26.6 34.6 38.9 31.4 37.5 35.4 35.5 36.0 36.7 15.8 n.a. 

RbX 31.5 27.3 31.7 42.0 37.8 45.0 32.3 42.7 44.0 49.0 13.6 n.a. 

SrX 330 302 286 354 313 353 317 335 308 331 397 353 

Ta 1.18 1.09 1.22 1.26 1.05 1.22 0.98 1.33 1.29 1.29 0.51 0.31 

Th 3.89 3.56 4.04 5.44 3.98 4.91 3.88 5.27 5.52 5.47 1.16 0.37 

u 1.11 0.88 0.93 1.64 1.22 1.56 0.85 1.66 1.45 1.56 0.52 n.a. 

YX 50.5 41.8 43.7 56.0 44.3 58.0 41.3 55.0 52.0 48.5 31 20.3 

Zn 208 17 0 173 152 163 216 172 165 153 141 123 112 

Zr 133 223 238 270 223 202 196 307 255 239 136 96 

ZrX 207 198 224 260 200 219 185 256 260 235 124 68 

Sc 39.9 36.0 37.3 31.5 36.1 38.6 35.8 33.4 33.6 30.6 40.1 36.7 

La 30.0 28.0 31.1 37.1 27.0 31.1 25.4 36.1 35.7 30.0 15.2 7.6 

Ce 58.9 57.4 62.7 82.0 54.2 57.7 51.0 75.2 77.7 64.4 32.3 16.3 

Nd 37.5 34.4 35.8 49.9 34.8 35.9 30.9 44.7 47.0 38.4 20.8 12.8 

Sm 9.4 7.9 7.6 11.7 6.9 9.0 6.1 11.1 11.2 9.0 4.2 2.7 

Eu 2.69 2.56 2.66 3.35 2.25 2.34 2.16 3.24 3.28 2.48 1.41 1.00 

Gd 9.2 8.6 9.4 11.5 7.9 8.9 7.9 10.1 10.5 8.7 5.0 3.6 

Tb 1.47 1.37 1.44 1.87 1.19 1.39 1.21 1.60 1.67 1.36 0.81 0.63 

Yb 4.62 3.92 4.62 5.69 3.89 4.63 3.52 5.55 5.62 4.65 3.08 2.10 

Lu 0.73 0.62 0.69 0.92 0.64 0.78 0.59 0.86 0.91 0.78 0.47 0.35 

Cu 45.0 37.3 27.7 n.a. 39.6 29.5 35.3 29.5 n.a. 15.0 105.7 78.7 

Ni 31.5 35.0 27.0 n.a. 33.6 46.5 39.3 2.5 n.a. 1 42.7 117 

Normalized major-oxide contents (weight percent) 

Si02 51.36 50.12 49.95 53.50 50.94 52.97 51.70 54.54 54.03 54.18 52.37 49.90 

Al203 15.44 14.17 13.44 14.50 14.27 14.02 13.48 13.91 14.31 14.58 15.47 16.82 

FeO 10.25 13.93 14.78 12.85 13.50 11.22 14.35 13.46 13.39 13.21 10.78 10.16 

MgO 3.76 5.16 4.50 3.21 4.57 4.31 4.44 2.90 2.96 2.89 5.91 8.21 

CaO 10.44 8.82 8.67 6.96 8.56 8. 73 8.08 6.41 6.52 6.50 9.90 10.83 

Na20 3.14 2.59 2.80 3.01 2.85 2.88 2.74 3.24 3.39 3.03 2.91 2.43 

K20 1.18 1.05 1.21 1.92 1.25 1.39 1.36 1.88 1.80 1.95 0.68 0.37 

Ti02 3.51 3.23 3.60 2.65 3.12 3.54 3.02 2.46 2.46 2.69 1.46 0.97 

P205 0.79 0.73 0.84 1.14 0.68 0. 71 0.61 0.90 0.89 0.75 0.36 0.17 

MnO 0.15 0.19 0.20 0.24 0.25 0.23 0.22 0.30 0.26 0.22 0.15 0.14 

Total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 

30 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Croup, Washington, Oregon, and Idaho 
Table 5. Average chemical composition of geochemical units in the Saddle Mountains Basalt 

[Chemical types listed in approximate stratigraphic order, see table 1. Trace elements followed by X analyzed by X-ray 

fluorescence; all others analyzed by instrumental neutron activation. n.a., not analyzed. Data from which these average 

compositions are calculated are given in Wright (1988)] 

Geochemical 

unit-------- LM GOOSE INDIAN MARTIN BASIN BUFORD ELEPHANT POMONA VC WEIPE ESQUAT RBESQUAT FS IC SLIP 

Chemical type- A B c D E F G H I J J K L 

Major oxides (weight percent) 

Si02 50.01 47.54 49.17 48.58 47.35 53.82 51.19 51.94 51.72 54.14 53.51 52.47 52.00 

Al203 14.12 12.34 13.76 13.69 13.74 14.17 13.26 15.02 15.30 13.82 14.35 13.48 14.29 

FeO 14.16 17.36 14.36 14.40 14.98 11.34 14.77 10.44 11.26 12.62 13.33 13.90 11.69 

MgO 4.87 4.50 5.40 5.87 6.03 4.98 4.17 7.18 6.49 3.97 3.70 4.20 5.47 

CaO 8.60 8.76 9.13 9.88 9.72 8.47 8.34 10.38 10.39 7.38 7.53 7.60 9.60 

Na20 2.68 2.42 2.41 2.36 2.27 2.77 2.44 2.23 2.53 2.57 2.54 2.66 2.64 

K20 1.43 1.21 1.00 0.74 0. 78 1.41 1.25 0.65 0.49 1. 71 1.65 1.61 0.91 

Ti02 2.92 3.80 3.40 3.31 3.69 2.21 3.60 1.62 1. 83 2.91 3.15 3.16 2.43 

P205 0.64 1.56 0.84 0.74 0. 87 0.38 0.60 0.24 0.29 0.44 0.42 0.52 0.53 

MnO 0.20 0.27 0.23 0.21 0.24 0.15 0.23 0.18 0.19 0.22 0.19 0.21 0.15 

Total 99.63 99.76 99.70 99.78 99.67 99.70 99.85 99.88 100.49 99.78 100.37 99.81 99.71 

Trace elements (parts per million) 

Ba 541 852 701 638 611 425 485 243 292 592 611 592 423 

BaX 523 830 687 612 603 444 320 173 265 577 658 481 308 

Co 41.6 38.1 41.6 43.1 46.5 39.2 45.0 43.5 n.a. 40.7 n.a. 46.1 43.8 

Cr 24.0 41.3 117.5 194.9 148.8 44.5 18.5 109.0 51.8 18.9 7.1 21.4 38.3 

Cs 1.23 0.45 0.50 n.a. n.a. 0.85 0.70 0.90 n.a. 0.98 0.89 0.78 n.a. 

Hf 4.63 10.74 6.74 5.90 6.59 5.30 6.41 3.23 3.28 5.57 5.81 5.38 4.40 

NbX 25.7 48.5 29.0 21.3 23.7 21.3 24.5 13.0 12.5 21.80 23.0 24.0 18.0 

Rb 18.0 30.1 28.3 20.6 19.8 35.5 27.6 10.0 9.0 47.3 32.0 35.30 19.0 

RbX 35.3 22.5 16.0 10.0 10.0 43.3 24.0 18.0 26.5 51.5 50.0 46.5 25.0 

SrX 350 220 233 235 227 230 213 227 235 257 269 245 244 

Ta 1.68 3.07 1.92 1.66 1. 91 1.53 1.74 0.82 0. 81 1.63 1.67 1.79 1.24 

Th 4.98 4.34 3.53 2.10 2.19 7.10 5.91 2.55 2.47 8.67 8.93 7.23 4.70 

u 1.38 1.12 0.90 0.65 0.75 1. 70 1.42 0.77 0.47 2.08 1.61 1.80 1.10 

)X 35.3 89.5 52.0 45.0 52.3 44.0 42.0 26.5 27.5 41.3 38.0 35.5 28.0 

Zn 147 226 173 161 177 129 179 118 102 134 127 164 135 

Zr 350 502 297 304 293 n.a. 316 n.a. 170 240 250 250 n.a. 

ZrX 189 436 273 238 273 216 229 137 140 226 223 219 180 

Sc 22.6 37.5 38.5 39.3 39.0 31.2 31.7 34.4 35.8 27.7 28.4 29.3 33.4 

La 35.3 74.1 46.0 36.8 42.9 33.0 33.7 17.0 17.1 38.2 38.6 35.8 28.0 

Ce 67.8 149 90.9 73.6 85.6 63.0 68.7 35.3 35.4 73.8 74.6 69.3 57.5 

Nd 34.0 86.9 53.3 47.3 53.7 33.5 35.3 20.5 21.1 36.7 38.5 34.3 31.0 

Sm 7.1 18.7 11.0 9.1 10.7 7.3 9.4 4.7 5.0 8.4 8.3 8.3 7.0 

Eu 2.10 5.41 3.22 2.82 3.31 1. 83 2.44 1.41 1.47 2.18 2.24 2.15 1.94 

Gd 8.2 18.4 10.1 9.0 9.7 6.9 8.7 5.0 5.1 8.0 8.2 8.2 7.5 

Tb 1.34 2.66 1.21 1.11 1.24 1.41 1.39 0.68 0.82 1.49 0.98 1.42 1.12 

Yb 3.13 9.08 5.55 5.01 5.64 3.90 4.58 2.73 2.66 3.65 3.58 3.75 3.40 

Lu 0.46 1.35 0.82 0.74 0.82 0.57 0.66 0.39 0.44 0.51 0.53 0.53 0.48 

Cu 17.5 27.0 39.0 33.0 46.0 32.5 39.7 63.0 n.a. 34.5 n.a. 28.0 n.a. 

Ni 28.5 9.8 13.0 34.0 42.0 40.5 30.7 51.3 n.a. 16.0 n.a. 16.0 n.a. 

Normalized major-oxide contents (weight percent) 

Si02 50.20 47.65 49.32 48.69 47.51 53.98 51.27 52.00 51.47 54.26 53.31 52.57 52.15 

Al203 14.17 12.37 13.80 13.72 13.79 14.21 13.28 15.04 15.23 13.85 14.30 13.51 14.33 

FeO 14.21 17.40 14.40 14.43 15.03 11.37 14.79 10.45 11.21 12.65 13.28 13.93 11.72 

MgO 4.89 4.51 5.42 5.88 6.05 4.99 4.18 7.19 6.46 3.98 3.69 4.21 5.49 

CaO 8.63 8.78 9.16 9.90 9.75 8.50 8.35 10.39 10.34 7.40 7.50 7.61 9.63 

Na20 2.69 2.43 2.42 2.37 2.28 2.78 2.44 2.23 2.52 2.58 2.53 2.67 2.65 

K20 1.44 1.21 1.00 0.74 0. 78 1.41 1.25 0.65 0.49 1. 71 1.64 1.61 0. 91 

Ti02 2.93 3. 81 3.41 3.32 3. 70 2.22 3.61 1.62 1. 82 2.92 3.14 3.17 2.44 

P205 0.64 1.56 0.84 0.74 0.87 0.38 0.60 0.24 0.29 0.44 0.42 0.52 0.53 

MnO 0.20 0.27 0.23 0.21 0.24 0.15 0.23 0.18 0.19 0.22 0.19 0.21 0.15 

Total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 

Tables and Figures 31 
Table 5. Average chemical composition of geochemical units in the Saddle Mountains Basalt-Continued 

Geochemical 

unit--------LEW ORCH SPRAGUE SW SPRAG NEW SW NEW ASOTIN VC ASOT SW HUNTZ HUNTZ VC LAP EAGLE WILBUR UMATILLA 

Chemical type- M N N 0 0 p p Q Q R R s T 

Major oxides (weight percent) 

Si02 49.63 50.76 49.65 49.22 50.11 50.76 51. 11 52.37 52.50 53.08 52.86 54.23 54.51 

Al203 15.22 13.72 14.54 15.64 15.95 16.02 16.54 16.05 15.39 15.85 15.35 14.46 14.18 

FeO 11.80 12.60 13.41 10.85 10.42 9.52 9.83 9.56 10.37 10.47 10.52 11.16 12.23 

MgO 7.09 5.07 6.39 7.97 7.41 8.23 7.88 7.56 6.52 5.84 5.99 4.50 2.74 

CaO 10.08 9.83 9.92 11.00 11.50 10.77 10.78 10.18 9.38 9.26 9.16 8.40 6.18 

Na20 2.32 2.64 2.63 2.19 2.51 2.29 1.99 2.43 2.34 2.33 2.45 2.64 3.37 

K20 0.46 0.87 0.61 0.40 0.29 0.39 0.46 0.65 1.22 1.32 1.15 1.76 2.55 

Ti02 2.42 3.17 2.73 1.89 1.93 1.48 1.48 1.47 1.63 1. 71 1.70 1.90 2.78 

P205 0.55 0.79 0.64 0.47 0.47 0.19 0.24 0.28 0.34 0.41 0.41 0.51 0.82 

MnO 0.21 0.18 0.22 0.15 0.18 0.14 0.20 0.20 0.20 0.17 0.13 0.23 0.19 

Total 99.78 99.63 100.74 99.78 100.77 99.79 100.51 100.75 99.89 100.44 99.72 99.79 99.55 

Trace elements (parts per million) 

Ba 410 767 506 320 342 303 277 352 410 665 570 876 3313 

BaX 351 598 486 329 336 249 278 262 n.a. 598 593 757 3184 

Co 43.8 46.2 n.a. 45.0 n.a. 46.9 n.a. n.a. 42.7 n.a. 41.2 42.5 28.1 

Cr 267.0 48.6 150.5 300.5 307.5 283.7 272.5 222.0 172.0 115.4 98.1 36.6 3.6 

Cs n.a. n.a. n.a. n.a. n.a. n.a. n.a. 0.34 0.50 0.63 0.70 0.80 0.73 

Hf 3.90 6.35 5.23 3.05 3.05 2.78 2.90 3.23 4.20 4.89 5.13 5.90 10.22 

NbX 18.0 28.0 23.0 18.0 16.5 13.0 12.0 13.0 n.a. 18.30 16 16.70 21.30 

Rb n.a. n.a. 17.5 n.a. 13.4 10.0 17.5 22.0 26.5 31.5 38.8 38.2 47.0 

RbX n.a. 6.0 n.a. 13.0 9.0 14.5 10.0 17.0 n.a. 34.30 24.0 43.3 43.0 

SrX 242 253 229 252 259 252 249 240 n.a. 274 296 277 276 

Ta 1.23 1.64 1.49 0.96 0.88 0.65 0.62 0.80 0.72 0.91 1.18 1.06 1.49 

Th 1.53 3.00 2.34 1.40 1.35 2.05 2.15 2.63 3.90 5.13 5.04 6.65 7.25 

u 0.95 1.45 0.61 n.a. 1 n.a. 0.70 0.61 0.50 1.08 1.17 1.10 1.43 

)X 34.5 47.0 46.5 35.0 33.0 26.7 25.0 24.0 n.a. 43.0 37.0 41.7 49.7 

Zn 131 162 128 116 111 107 103 87 103 117 126 131 135 

Zr 203 360 255 n.a. 160 n.a. 126 140 195 230 234 282 520 

ZrX 172 274 228 141 134 121 120 141 n.a. 216 164 249 482 

Sc 37.3 37.4 38.5 34.6 35.7 30.8 30.9 29.2 28.7 27.8 29.0 26.6 26.2 

La 27.8 42.5 34.7 20.0 20.5 15.7 15.0 17.7 27.0 33.3 31.6 43.7 46.7 

Ce 56.0 87.0 73.9 41.0 41.5 31.5 30.5 36.2 52.0 62.1 61.2 80.5 88.2 

Nd 29.3 48.0 42.4 24.0 27.0 18.0 19.0 19.5 27.5 33.8 32.3 39.5 49.2 

Sm 6.8 10.3 9.2 5.3 5.1 4.3 4.0 4.5 5.9 6.6 6.5 7.8 9.8 

Eu 2.03 2.69 2.44 1.61 1. 71 1.28 1.29 1.30 1.56 1. 71 1.92 1.93 3.95 

Gd 6.9 9.5 8.2 4.2 6.4 4.7 4.5 4.4 5.6 6.8 7.2 7.6 10.2 

Tb 1.11 1.63 1.32 0.86 0.93 0.74 0.80 0.73 0.82 0.99 1.04 1.32 1.69 

Yb 3.53 4.80 4.17 2.50 2.85 2.37 2.45 2.30 2.85 3.59 3.85 4.23 4.52 

Lu 0.53 0.69 0.75 0.40 0.42 0.35 0.35 0.49 0.55 0.56 0.56 0.63 0.66 

Cu 59.5 46.0 57.0 67.0 89.0 111.7 100.0 96.0 n.a. 49.0 52.5 25.0 19.0 

Ni 84.5 70.0 85.0 140.0 140.0 203.3 140.0 170.0 n.a. 54.0 93.0 47.0 2.7 

Normalized major-oxide contents (weight percent) 

Si02 49.74 50.95 49.29 49.33 49.73 50.87 50.85 51.98 52.56 52.85 53.01 54.34 54.76 

Al203 15.25 13.77 14.43 15.67 15.83 16.05 16.46 15.93 15.41 15.78 15.39 14.49 14.24 

FeO 11.83 12.65 13.31 10.87 10.34 9.54 9.78 9.49 10.38 10.42 10.55 11.18 12.29 

MgO 7.11 5.09 6.34 7.99 7.35 8.25 7.84 7.50 6.53 5.81 6.01 4.51 2.75 

CaO 10.10 9.87 9.85 11.02 11.41 10.79 10.73 10.10 9.39 9.22 9.19 8.42 6.21 

Na20 2.33 2.65 2.61 2.19 2.49 2.29 1.98 2.41 2.34 2.32 2.46 2.65 3.39 

K20 0.46 0.87 0.61 0.40 0.29 0.39 0.46 0.65 1.22 1. 31 1.15 1.76 2.56 

Ti02 2.43 3.18 2.71 1.89 1.92 1.48 1.47 1.46 1.63 1. 70 1.70 1.90 2.79 

P205 0.55 0.79 0.64 0.47 0.47 0.19 0.24 0.28 0.34 0.41 0.41 0.51 0.82 

MnO 0.21 0.18 0.22 0.15 0.18 0.14 0.20 0.20 0.20 0.17 0.13 0.23 0.19 

Total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 

32 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
Table 5. Average chemical 

composition of geochemical units in 

the Saddle Mountains BasaltContinued 

Geochemical 

unit-------UM FRAC 

Chemical type- T 

PH UMTIL PH SOPHER 

T U 

Major oxides (weight percent) 

Si02 

Al203 

FeO 

MgO 

CaO 

Na20 

K20 

Ti02 

P205 

MnO 

Total 

59.09 

16.62 

5.79 

0.60 

5.32 

4.10 

3.51 

3.27 

1.20 

0.06 

99.56 

55.56 

15.04 

11.77 

2.49 

6.01 

3.16 

2.60 

2. 71 

0.97 

0.19 

100.50 

54.49 

15.08 

11.76 

2.89 

6.63 

3.06 

2.41 

3.06 

0.86 

0.23 

100.47 

Trace elements (parts per million) 

Ba 

BaX 

Co 

Cr 

Cs 

Hf 

NbX 

Rb 

RbX 

SrX 

Ta 

Th 

u 

'YX 

Zn 

Zr 

ZrX 

Sc 

La 

Ce 

Nd 

Sm 

Eu 

Gd 

Tb 

Yb 

Lu 

Cu 

Ni 

4410 

4161 

12.7 

3.2 

0.69 

12.48 

25.0 

59.8 

56.0 

346 

1.58 

8.89 

1.74 

54.0 

199 

631 

546 

29.9 

57.0 

114.4 

57.3 

12.6 

5.15 

12.0 

1. 74 

4.39 

0.66 

5.0 

n.a. 

3585 

3478 

n.a. 

1.7 

0.63 

10.55 

20.0 

56.3 

44.0 

285 

1.62 

7.45 

1.42 

49.0 

135 

543 

517 

25.8 

48.8 

89.3 

50.5 

9.5 

4.12 

10.70 

1.49 

4.55 

0.66 

26.0 

75.0 

3153 

3281 

n.a. 

1.4 

0.65 

9.83 

17.5 

42.3 

35.0 

338 

1.44 

7.00 

1.02 

43.0 

139 

494 

462 

27.4 

45.0 

85.5 

43.3 

8.5 

3.68 

9.2 

1.29 

4.28 

0.65 

15.0 

5.0 

Normalized major-oxide contents 

(weight percent) 

Si02 

Al203 

FeO 

MgO 

CaO 

Na20 

K20 

Ti02 

P205 

MnO 

Total 

59.35 

16.69 

5.82 

0.60 

5.34 

4.12 

3.53 

3.28 

1.21 

0.06 

100.00 

55.28 

14.97 

11.71 

2.48 

5.98 

3.14 

2.59 

2.70 

0.97 

0.19 

100.00 

54.24 

15.01 

11.70 

2.88 

6.60 

3.05 

2.40 

3.05 

0.86 

0.23 

100.00 

Tables and Figures 33 
Table 6. Average chemical composition of feeder dikes in the Yakima Basalt Subgroup 

[Chemical types listed in approximate stratigraphic order, see table 1. Trace elements followed by X analyzed by X-ray fluorescence; all others 

analyzed by instrumental neutron activation. n. a., not analyzed. Data from which these average conpositions are calculated are given in Wright 

(1988). GRB CT1 and GRB CT3 refer to geochemical units 1 and 3 in table 3] 

Geochemical 

unit--------ELEPHANT UMATILLA LOLOINC ROSALIA ROZA FSINC SHUMAKER DODGE ROBIN GRB CT1 GRB CT3 GRB CT3 GRB LH2 GRB MG6 

Chemical type- G T B c E F G J A C C 1 2 

Si02 

Al203 

FeO 

MgO 

CaO 

Na20 

K20 

Ti02 

P205 

MnO 

Total 

Ba 

BaX 

Co 

Cr 

Cs 

Hf 

NbX 

Rb 

RbX 

SrX 

Ta 

u 

)X 

Zn 

Zr 

ZrX 

Sc 

La 

Ce 

Nd 

Sm 

Eu 

Gd 

Tb 

Yb 

Lu 

Cu 

Ni 

Si02 

Al203 

FeO 

MgO 

CaO 

Na20 

K20 

Ti02 

P205 

MnO 

Total 

51.25 

13.22 

14.75 

4.07 

8.10 

2.64 

1.22 

3.76 

0.49 

0.20 

99.70 

447 

480 

41.3 

18.3 

0.50 

6.10 

10.0 

35.0 

15.0 

382 

1. 71 

1.20 

29.0 

137 

190 

125 

28.9 

31.0 

60.0 

34.0 

8.3 

2.41 

8.8 

1.22 

4.30 

0.63 

25.0 

14.0 

51.40 

13.26 

14.79 

4.08 

8.12 

2.65 

1.22 

3.77 

0.49 

0.20 

100.00 

54.68 

13.07 

13.34 

3.03 

5.66 

3.24 

2.51 

2.72 

1.02 

0.17 

99.44 

3510 

3460 

25.3 

4.1 

n.a. 

9.80 

5.0 

42.0 

44.0 

291 

1.40 

1.20 

48.0 

134 

519 

484 

25.0 

45.0 

86.0 

47.0 

10.2 

4.24 

10.5 

1. 39 

4.20 

0.63 

2.0 

1.0 

54.99 

13.14 

13.42 

3.05 

5.69 

3.26 

2.52 

2.74 

1.03 

0.17 

100.00 

50.15 

13.57 

13.77 

5.26 

8.47 

2.73 

0.84 

3.25 

0.83 

0.18 

99.65 

460 

490 

36.1 

91.5 

1.20 

3.90 

17.5 

28.5 

31.0 

330 

3.00 

0.75 

40.5 

131 

150 

180 

32.7 

24.0 

49.0 

30.5 

7.6 

2.34 

6.5 

1.09 

3.65 

0.54 

43.5 

44.0 

50.93 

13.62 

13.82 

5.28 

8.50 

2.74 

0.84 

3.26 

0.83 

0.18 

100.00 

50.23 

12.76 

15.35 

4.53 

8.19 

2.47 

1.13 

3. 71 

0.84 

0.19 

99.40 

531 

544 

36.5 

18.5 

n.a. 

5.00 

19.0 

19.0 

20.0 

345 

3.60 

0.80 

45.0 

154 

210 

216 

36.7 

28.0 

55.0 

33.0 

1.5 

2.45 

7.8 

1.17 

4.40 

0.63 

30.0 

14.0 

50.53 

12.84 

15.44 

4.56 

8.24 

2.48 

1.14 

3.73 

0.85 

0.19 

100.00 

Major oxides (weight percent) 

51.07 

13.46 

14.05 

4.59 

8.33 

2.75 

1.43 

3.26 

0.60 

0.23 

99.77 

51.43 

13.49 

14.19 

4.54 

8.12 

2. 73 

1.34 

2.94 

0.62 

0.25 

99.65 

54.43 

13.06 

13.42 

2.91 

6.65 

3.51 

2.01 

2.47 

0.83 

0.28 

99.57 

51.94 

14.56 

10.70 

6.42 

10.16 

3.16 

0.61 

1.53 

0.36 

0.16 

99.60 

49.43 

16.58 

10.39 

8.59 

11.03 

2.35 

0.23 

0.92 

0.18 

0.19 

99.89 

54.29 

14.49 

11.15 

4.90 

8.53 

2.86 

1.22 

1. 73 

0.35 

0.19 

99.71 

53.22 

14.44 

11.47 

5.49 

9.11 

2.75 

1.11 

1.73 

0.32 

0.17 

99.81 

Trace elements (parts per million) 

560 

559 

39.1 

33.6 

0.80 

4.90 

19.0 

38.0 

39.0 

322 

4.20 

1.10 

40.0 

140 

200 

200 

37.4 

27.0 

56.0 

33,0 

8.4 

2.42 

8.2 

1.21 

4.10 

0.60 

32.0 

19.0 

537 

524 

38.7 

46.6 

0.95 

4.50 

15.0 

41.3 

39.5 

318 

4.10 

0.93 

36.5 

146 

145 

185 

35.4 

24.3 

49.3 

27.8 

5.6 

2.02 

7.9 

1.10 

3. 73 

0.54 

29.5 

10.0 

1070 

1050 

23.9 

4.4 

0.60 

6.50 

20.0 

51.0 

53.0 

342 

5.10 

1.50 

59.0 

165 

270 

263 

36.0 

38.0 

79.0 

47.0 

10.8 

3.58 

12.7 

1.72 

5.80 

0.86 

17.0 

1.0 

357 

345 

36.1 

161.0 

n.a. 

3.00 

10.0 

13.0 

14.0 

377 

1.10 

n.a. 

28.0 

110 

90 

124 

46.0 

14.0 

30.0 

21.0 

4.9 

1.40 

6.4 

0. 73 

3.10 

0.48 

110.0 

41.0 

145 

151 

45.9 

152.5 

n.a. 

1.55 

9.0 

4.0 

6.0 

332 

0.50 

n.a. 

21.5 

89 

n.a. 

74 

36.5 

7.0 

15.0 

10.5 

2.9 

0.94 

2.3 

0.55 

2.35 

0.35 

92.0 

93.0 

487 

498 

38.1 

44.1 

0.90 

3.50 

12.0 

32.0 

32.0 

346 

3.20 

0.80 

31.0 

120 

120 

151 

33.6 

18.0 

36.0 

21.0 

49.0 

1.48 

55.0 

0.81 

3.00 

0.44 

50.0 

21.0 

401 

427 

38.7 

83.6 

0.65 

3.20 

12.5 

27.5 

27.5 

343 

2.55 

0.80 

29.5 

105 

170 

143 

36.3 

16.0 

33.0 

22.0 

4.6 

1.50 

4.8 

0.71 

2.85 

0.45 

55.0 

23.5 

Normalized major-oxide contents (weight percent) 

51.19 

13.49 

14.08 

4.60 

8.35 

2.76 

1.43 

3.27 

0.60 

0.23 

100.00 

51.61 

13.54 

14.24 

4.56 

8.15 

2.74 

1. 34 

2.95 

0.62 

0.25 

100.00 

54.67 

13.12 

13.48 

2.92 

6.68 

3.53 

2.02 

2.48 

0.83 

0.28 

100.00 

52.15 

14.62 

10.74 

6.45 

10.20 

3.17 

0.61 

1.54 

0.36 

0.16 

100.00 

49.48 

16.60 

10.40 

8.60 

11.04 

2.35 

0.23 

0.92 

0.18 

0.19 

100.00 

54.45 

14.53 

11.18 

4.91 

8.55 

2.87 

1.22 

1.74 

0.35 

53.32 

14.47 

11.49 

5.50 

9.13 

2.76 

1.11 

1.73 

0.32 

0.19 0.17 

100.00 100.00 

54.54 

14.21 

11.39 

4.57 

8.09 

3.15 

1.22 

1.93 

0.33 

0.17 

99.60 

524 

525 

35.3 

26.6 

0.90 

4.30 

12.5 

41.0 

40.5 

329 

4.20 

1.20 

32.0 

118 

230 

172 

33.0 

20.5 

39.5 

22.5 

5. 7 

1.68 

7.0 

0.95 

3.25 

0.47 

35.5 

12.0 

54.76 

14.27 

11.44 

4.59 

8.12 

3.16 

1.22 

1.94 

0.33 

0.17 

100.00 

34 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 

54.48 

14.83 

9.48 

6.15 

9.39 

2.80 

0.96 

1.27 

0.29 

0.16 

99.81 

390 

433 

32.1 

86.3 

0.40 

2.70 

11.0 

20.5 

23.5 

392 

1.75 

0.45 

25.5 

90 

125 

126 

36.4 

14.5 

30.0 

17.5 

4.1 

1.22 

4.0 

0.60 

2.40 

0.37 

67.0 

23.5 

54.58 

14.863 

9.50 

6.16 

9.41 

2.81 

0.96 

1.27 

0.29 

0.16 

100.00 

52.56 

14.38 

11.63 

5.82 

9.29 

2.72 

1.03 

1.78 

0.36 

0.17 

99.74 

419 

434 

38.7 

112.1 

0.68 

3.18 

12.0 

31.8 

31.0 

386 

2.25 

0.65 

29.3 

114 

160 

140 

38.8 

16.5 

32.8 

19.5 

13.4 

1.52 

4.4 

0.70 

3.00 

0.44 

54.7 

20.3 

52.70 

14.42 

11.66 

5.84 

9.31 

2.73 

1.03 

1.7 8 

0.36 

0.17 

100.00 
Table 7. Ratios of incompatible trace elements in samples of the Grande Ronde Basalt 

[Geochemical units listed in approximate stratigraphic order, see table 1. n. a., not analyzed] 

Geochemical 

unit------- lA N2 lA* N2 2A N2 

Chemical type- A A B 

K/Rb 

K/Th 

KIP 

Kill a 

KISr 

RbiSr 

HfiTh 

HfiBa 

HfiZr 

Hf/Ta 

Hf/La 

Th/Ba 

LaiSm 

LaiYb 

Geochemical 

3.48 

27.14 

7.04 

19.71 

34.05 

9.79 

0.99 

7.20 

24.40 

5.52 

18.73 

7.30 

2.25 

4.66 

3.18 

30.44 

8.96 

20.41 

33.72 

10.62 

1.03 

6.90 

22.20 

5.14 

20.00 

6.70 

2.13 

4.21 

n.a. 

n.a. 

5.5 8 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

unit------- LH2 N2 MG6 N2 2B N2 

Chemical type- 1 2 B 

KIRb 

KITh 

KIP 

KIBa 

KISr 

RbiSr 

Hf/Th 

HfiBa 

HfiZr 

Hf/Ta 

Hf/La 

ThiBa 

La/Sm 

LaiYb 

Geochemical 

2.49 

32.31 

4.72 

16.11 

13.80 

5.54 

1. 50 

7.50 

22.20 

6.44 

17.76 

5.00 

2.21 

5.34 

2.14 

23.97 

4.25 

14.15 

14.60 

6. 82 

1. 36 

8.00 

24.10 

5.10 

19.04 

5.90 

2.30 

3. 91 

n.a. 

27.67 

9.14 

n.a. 

n.a. 

n.a. 

0.83 

n.a. 

n.a. 

7.66 

16.33 

n.a. 

2.44 

5.24 

uni t--------SC* N2R2 3D R2 SD R2 

Chemical type- E C E 

KIRb 

K/Th 

KIP 

K/Ba 

K/Sr 

Rb/Sr 

Hf/Th 

HfiBa 

Hf/Zr 

Hf/Ta 

Hf/La 

Th/Ba 

La/Sm 

La/Yb 

Geochemical 

n.a. 

n.a. 

12.83 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

2.52 

26.39 

8.04 

18.83 

29.65 

11.79 

1.08 

7.70 

22.70 

5.03 

20.33 

7.10 

2.10 

4.44 

n.a. 

26.71 

10.36 

n.a. 

n.a. 

n.a. 

0.86 

n.a. 

n.a. 

4.55 

19.05 

n.a. 

2.29 

5.11 

unit-------- 3E Nl UNC Nl 3F Nl 

Chemical type- C X c 

K/Rb 

K/Th 

KIP 

K/Ba 

K/Sr 

Rb/Sr 

Hf/Th 

Hf/Ba 

Hf/Zr 

Hf/Ta 

Hf/La 

Th/Ba 

La/Sm 

La/Yb 

3.18 

26.52 

9.11 

27.59 

32.04 

10.07 

1. 00 

10.40 

24.90 

5.23 

21.75 

10.40 

1. 91 

4.44 

n.a. 3.21 

33.47 25.97 

7.14 8.52 

n.a. 17.61 

n.a. 26.87 

n.a. 8.38 

1.10 1.01 

n.a. 6. 80 

n.a. 23.40 

5.70 5.31 

20.00 20.75 

n.a. 6.80 

1.95 1.96 

4.27 4.58 

UNC N2 

X 

n.a. 

n.a. 

4.99 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

SA N2 

E 

2.99 

24.89 

11.00 

22.02 

47.05 

15.73 

0.77 

6.80 

25.10 

5.23 

18.02 

8. 80 

2.48 

5.46 

3A N2 

c 

3.28 

24.53 

6. 82 

18.25 

25.70 

7.83 

1.11 

8.20 

24.10 

5.42 

19.70 

7.40 

2.16 

4.15 

SA* N2 

E 

2.69 

23.04 

11.41 

20.52 

43.38 

16.13 

0.76 

6.70 

25.10 

5.28 

17.21 

8. 90 

2.59 

5.34 

3A* N2 UNC N2 

C X 

3.10 

26.86 

9.09 

20.11 

27.26 

8.81 

1.13 

8.50 

24.40 

5.27 

19.74 

7.50 

2.12 

3.96 

UNC N2 

X 

n.a. 

n.a. 

5.81 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

3.19 

28.93 

7.09 

20.97 

31.71 

9.94 

1.14 

8.30 

24.60 

5.45 

20.25 

7.20 

2.17 

4.15 

2C N2 

B 

2.95 

26.55 

8.65 

21.52 

44.97 

15.27 

0.86 

7.00 

25.10 

5.41 

17.63 

8.10 

2.40 

5.13 

SD* R2 

E 

SD* R2 UNC R2 2D R2 

E X B 

n.a. 

n.a. 

10.53 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

11.06 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

SE Nl AS16 Nl 

E 3 

n.a. 

32.36 

9.19 

n.a. 

n.a. 

n.a. 

1.10 

n.a. 

n.a. 

5.94 

21.03 

n.a. 

1.95 

4.09 

2.96 

27.61 

7. 71 

19.74 

36.40 

12.31 

0.97 

6.90 

23.80 

5.46 

20.19 

7.10 

2.04 

4. 51 

n.a. 

27.57 

7.32 

n.a. 

n.a. 

n.a. 

0.90 

n.a. 

n.a. 

4.84 

18.28 

n.a. 

2.19 

5.13 

3G Nl 

c 

n.a. 

28.59 

8.73 

n.a. 

n.a. 

n.a. 

1. 05 

n.a. 

n.a. 

5. 74 

20.71 

n.a. 

2.07 

4.51 

3.28 

27.72 

8.40 

23.13 

47.51 

14.49 

0.87 

7.20 

25.30 

5.42 

18.33 

8.30 

2.22 

5.12 

SF Nl 

E 

3.43 

29.69 

9.63 

20.14 

40.23 

11.73 

1.09 

7.40 

24.40 

5.71 

22.22 

6.80 

1.97 

4.43 

4A N2 

D 

3.20 

25.07 

5.93 

18.60 

26.75 

8.36 

1.13 

8.40 

24.00 

5.28 

20.52 

7.40 

2.03 

4.08 

4C N2 

D 

n.a. 

n.a. 

5.50 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

4A* N2 Unc N2 

D X 

3.58 

28.82 

7.92 

23.64 

30.70 

8.58 

1.08 

8.90 

23.80 

5.42 

20.53 

8.20 

2.23 

4.05 

n.a. 

n.a. 

13.03 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

3B N2 

c 

3.16 

26.99 

8.01 

19.59 

29.87 

9.45 

1.05 

7.60 

23.60 

5.51 

18.91 

7.30 

2.19 

4.25 

UNC N2 

X 

n.a. 

n.a. 

6.45 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

4B N2 

D 

n.a. 

n.a. 

5. 33 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

SB N2 

E 

3C N2 3C* N2 UNC N2 SC N2R2 

2.99 

25.99 

11.35 

22.18 

49.70 

16.61 

0.76 

6.40 

25.10 

5.30 

17.87 

8.50 

2.50 

5.15 

C C X E 

3.46 

29.29 

8.22 

24.38 

30.81 

8.90 

1.06 

8.90 

25.20 

5.00 

19.62 

8.30 

2.10 

4.53 

3.13 

29.69 

7.96 

19.79 

26.50 

8.47 

1.13 

7.60 

24.20 

4.97 

19.14 

6.70 

2.11 

3.98 

n.a. 

n.a. 

5.95 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

9.45 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

2D* R2 UNC R2 AS16 R2 2E R2Nl UNC* Nl KBS Nl 

B X 3 B X 4 

2.89 

24.63 

9.30 

21.04 

45.39 

15.71 

0.80 

6.80 

25.10 

5.47 

17.97 

8.50 

2.36 

5.04 

2. 81 

24.65 

7.64 

18.35 

48.55 

17.27 

0.75 

5.60 

25.40 

5.52 

17.61 

7.40 

2.40 

5.25 

n.a. 

28.76 

7.84 

n.a. 

n.a. 

n.a. 

1.06 

n.a. 

n.a. 

5.66 

21.38 

n.a. 

1. 88 

4.07 

n.a. 

n.a. 

10.46 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

UNC Nl AS16 Nl SG Nl AS16 Nl 

X 3 E 3 

n.a. 

n.a. 

5.50 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

2.89 

29.56 

8.62 

20.02 

36.90 

12.75 

1. 11 

7.50 

23.80 

5.96 

21.58 

6. 80 

2.02 

4.36 

n.a. 

n.a. 

9.87 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

25.60 

8.10 

n.a. 

n.a. 

n.a. 

1.08 

n.a. 

n.a. 

5.69 

21.85 

n.a. 

1.9 8 

4.57 

n.a. 

n.a. 

6.95 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

n.a. 

3.10 

31.18 

6. 84 

21.00 

36.65 

11.84 

1.06 

7.10 

24.00 

5.12 

20.05 

6.70 

1.96 

4.14 

51! Nl AS16 Nl 

E 3 

n.a. 

29.43 

10.95 

n.a. 

n.a. 

n.a. 

0.98 

n.a. 

n.a. 

5.13 

21.29 

n.a. 

2.00 

4.64 

n.a. 

28.74 

9.97 

n.a. 

n.a. 

n.a. 

1. 01 

n.a. 

n.a. 

5.34 

21.82 

n.a. 

1. 93 

4.20 

Tables and Figures 35 
Table 7. Ratios of incompatible trace elements in 

samples of the Grande Ronde Basalt-Continued 

Geochemical 

unit--------UNC Nl AS16 Nl 2F Rl SI Rl AS16 Rl 

Chemical type- X 3 B E 3 

K/Rb 2.58 2.60 3.08 n.a. n.a. 

K/Th 28.43 26.98 29.50 25.41 31.54 

KIP 11.82 10.37 7.42 9.87 8.05 

K/Ba 26.06 20.60 22.21 n.a. n.a. 

KISr 49.02 42.90 42.46 n.a. n.a. 

RbiSr 18.99 16.51 13.77 n.a. n.a. 

Hf/Th 0.90 0.95 1.17 0.92 1.22 

Hf/Ba 8.20 7.20 8.80 n.a. n.a. 

HfiZr 24.10 23.90 25.70 n.a. n.a. 

Hf/Ta 5.49 5.93 6.18 5.54 5.27 

Hf/La 21.05 21.21 22.40 21.71 21.89 

Th/Ba 9.20 7.60 7.50 n.a. n.a. 

LaiSm 2.10 2.05 1.94 2.11 1.93 

LaiYb 4.83 4.89 4.14 5.11 4.12 

Table 8. Ratios of incompatible trace elements in samples of the Wanapum Basalt 

[Geochemical units listed in approximate stratigraphic order, see table 1. n. a., not analyzed] 

Geochemical 

unit-------- PV LOLO INC ROSALIA PH POWAT ROZA FS ANOM FS INC SHUMAKER PH SHUM SW LOOK DODGE ROBIN 

Chemical type- A B c D E F F G G H J 

KIRb 3.11 3.19 3.17 3.81 2.75 2.55 3.47 3.64 3.41 3.32 4.15 n.a. 

KITh 25.18 24.48 24.86 29.45 26.07 23.33 28.88 29.46 27.22 29.75 48.66 48.23 

KIP 2.84 2.73 2.74 3.19 3.50 3. 70 4.21 3.95 3.87 4.97 3.59 2.40 

K/Ba 15.07 18.12 19.17 16.78 18.14 14.20 24.52 15.51 15.46 21.38 17.26 11.86 

K!Sr 29.68 28.86 35.12 45.26 33.15 32.45 35.35 46.34 48.78 49.16 14.22 5.03 

RbiSr 9.55 9.04 11.08 11.86 12.08 12.75 10.19 12.75 14.29 14.80 3.43 n.a. 

Hf/Th 1.29 1. 31 1.34 1.18 1.17 1.03 1.14 1.17 1.15 1.03 2.47 4.00 

Hf/Ba 7.70 9.70 10.40 6.70 8.10 6.30 9.70 6.20 6.50 7.40 8.70 11.00 

Hf/Zr 24.30 23.50 24.20 24.60 23.20 23.20 23.90 24.10 24.30 24.00 23.10 21.80 

Hf/Ta 4.25 4.28 4.45 5.08 4.42 4.16 4.51 4.63 4. 91 4.36 5.61 4.77 

Hf/La 16.73 16.64 17.46 17.25 17.19 16.33 17.40 17.06 17.73 18.77 18.82 19.47 

ThiBa 6.00 7.40 7.70 5.70 7.00 6.10 8.50 5.30 5.70 7.20 3.50 2.70 

La/Sm 1. 95 2.16 2.49 1.93 2.39 2.11 2.54 1.98 1. 94 2.03 2.21 1.72 

La/Yb 4.29 4.72 4.44 4.31 4.58 4.44 4.76 4.30 4.19 4.26 3.26 2.39 

36 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
Table 9. Ratios of incompatible trace elements in samples of the Saddle Mountain Basalt 

[Geochemical units listed in approximate stratigraphic order, see table 1. n.a., not analyzed} 

Geochemical 

unit-------- 1M GOOSE INDIAN MARTIN BASIN BUFORD ELEPHANT POMONA VC WEIPE ESQUAT RBESQUAT FS IC SLIP 

Chemical type- A B c D E F G H J J K L 

KIRb 3.36 4.46 5.19 6.14 6.48 2.70 4.32 3.00 1.53 2.76 2.74 2.87 3.02 

KITh 23.84 23.14 23.52 29.25 29.57 16.49 17.56 21.16 16.47 16.37 15.34 18.49 16.07 

KIP 4.25 1.47 2.26 1.90 1. 70 7.05 3.96 5.15 3.21 7.39 7.47 5.89 3.26 

KIBa 22.70 12.10 12.08 10.04 10.74 26.36 32.43 31.19 15.35 24.60 20.82 27.79 24.53 

KISr 33.92 45.66 35.63 26.14 28.52 50.89 48.72 23.77 17.31 55.24 50.92 54.55 30.96 

RbiSr 10.09 10.23 6.87 4.26 4.41 18.83 11.27 7.93 11.28 20.04 18.59 18.98 10.25 

Hf/Th 0.93 2.47 1. 91 2.81 3.01 0.75 1.08 1.27 1.33 0.64 0.65 0.74 0.94 

HfiBa 8.90 12.90 9.80 9.60 10.90 11.90 20.00 18.70 12.40 9.70 8.80 11.20 14.30 

Hf/Zr 24.50 24.60 24.70 24.80 24.10 24.50 28.00 23.60 23.40 24.60 26.10 24.60 24.40 

Hf/Ta 2.76 3.50 3.51 3.55 3.45 3.46 3.6 8 3.94 4.05 3.42 3.48 3.01 3.55 

Hf/La 13.12 14.49 14.65 16.03 15.36 16.06 19.02 19.00 19.18 14.58 15.05 15.03 15.71 

ThiBa 9.50 5.20 5.10 3.40 3.60 16.00 18.50 14.70 9.30 15.00 13.60 15.00 15.30 

LaiSm 3.03 2.42 2.55 2.46 2.44 2.76 2.19 2.20 2.08 2.77 2.83 2.63 2.44 

LaiYb 7.45 5.39 5.47 4.85 5.02 5.59 4.86 4.11 4.24 6.91 7.12 6.30 5.44 

Geochemical 

unit--------LEW ORCH SPRAGUE SW SPRAG NEW SW NEW ASOTIN VC ASOT SW HUNTZ HUNTZ VC LAP EAGLE WILBUR UMATILLA 

Chemical type- M N N 0 0 p Q Q R R T 

KIRb n.a. 12.04 0.00 2.55 2.67 2.23 3.82 3.17 0.00 3.19 3.98 3.37 4.92 

KITh 4.96 24.07 21.64 23.72 17.83 15.79 17.76 20.52 25.97 21.36 18.94 21.97 29.20 

KIP .59 2.09 1.81 1.62 1.17 3.90 3.64 4.41 6.82 6.12 5.33 6.56 5.91 

KIBa 0.88 12.08 10.42 10.09 7.16 13.00 13.74 20.60 0.00 18.32 16.10 19.30 6.65 

KISr 5. 78 28.55 22.11 13.18 9.30 12.85 15.34 22.48 0.00 39.99 32.25 52.75 76.70 

RbiSr .00 2.37 0.00 5.16 3.47 5.75 4.02 7.08 0.00 12.52 8.11 15.63 15.58 

Hf/Th .55 2.12 2.24 2.18 2.26 1.36 1.35 1.23 1.08 0.95 1.02 0.89 1.41 

HfiBa 1.10 10.60 10.80 9.30 9.10 11.20 10.40 12.30 0.00 8.20 8.70 7.80· 3.20 

Hf/Zr 2.70 23.20 22.90 21.60 22.80 23.00 24.20 22.90 0.00 22.60 31.30 23.70 21.20 

Hf/Ta .17 3.87 3.51 3.18 3.47 4.28 4.68 4.04 5.83 5.37 4.35 5.57 6.86 

Hf/La 4.03 14.94 15.07 15.25 14.88 17.71 19.33 18.25 15.56 14.68 16.23 13.50 21.88 

ThiBa .40 5.00 4.80 4.30 4.00 8.20 7.70 10.00 0.00 8.60 8.50 8.80 2.30 

LaiSm .49 2.52 2.30 2.30 2.45 2.23 2.29 2.40 2.79 3.08 2.96 3.41 2.90 

LaiYb .20 5.85 5.49 5.28 4.75 4.37 4.04 5.08 6.26 6.12 5.42 6.82 6.82 

Geochemical 

unit--------UM FRAC PH UMTIL PH SOPHER 

Chemical type- T T u 

KIRb 5.20 4.91 5.72 

KITh 32.78 28.97 28.58 

KIP 5.56 5.10 5.33 

KIBa 7.00 6.21 6.10 

KISr 84.21 75.73 59.19 

RbiSr 16.18 15.44 10.36 

Hf/Th 1.40 1.42 1.40 

HfiBa 3.00 3.00 3.00 

Hf/Zr 22.90 20.40 21.30 

Hf/Ta 7.90 6.51 6.83 

Hf/La 21.89 21.62 21.84 

ThiBa 2.10 2.10 2.10 

La/Sm 2.76 3.13 3.23 

La/Yb 8.57 7.08 6.94 

Tables and Figures 37 
Table 10. Corrected and normalized major-oxide chemistry of naturally quenched glass from 

the Grande Ronde Basalt 

[Geochemical units listed in approximate stratigraphic order, see table 1. Chemical type names for 

glasses correspond to the chemical types for whole rocks. Data are averages computed from original data 

given in Wright (1988)] 

Geochemical 

unit------- lA* GL 3A* GL 4A* GL LH2N2 GL MG6N2 GL SA* GL 3C* GL SC* GL SD* GL 2D* GL 

Chemical type- A c D 1 2 E c E E B 

Si02 54.82 54.36 54.30 55.41 52.47 56.26 54.51 57.37 55.98 55.74 

Al203 13.89 13.59 13.43 14.38 14.08 13.24 13.45 13.10 12.92 12.96 

FeO 11.90 12.27 12.77 10.42 12.57 12.51 12.79 12.24 12.98 12.98 

MgO 4.08 4.39 4.08 5.00 5.25 3.18 3.96 2.83 3.03 2.80 

CaO 8.18 8. 71 8.21 9.21 9.67 7.04 7.93 6.69 6.89 6.75 

Na20 3.15 3.04 3.10 3.01 2.97 3.39 3.30 3.21 3.41 3.44 

K2o 1.60 1.35 1.50 0.88 0. 81 1.90 1.45 2.01 2.05 2.13 

Ti02 2.04 2.03 2.26 1.41 1. 87 2.16 2.26 2.22 2.38 2.77 

P2o5 0.34 0.27 0.36 0.28 0.31 0.32 0.35 0.33 0.35 0.44 

Total 100.00 100.01 100.01 100.00 100.00 100.00 100.00 100.00 99.99 100.01 

Table 11. Corrected and normalized major-oxide chemistry 

of naturally quenched glaass from the Wanapum Basalt 

[Geochemical units listed in approximate stratigraphic order, see 

table 1. Chemical type names for glasses correspond to the chemical 

types for whole rocks. Data are averages computed from original 

data given in Wright (1988)] 

Geochemical 

unit--------LOLO GL ROSAL GL ROZA GL FRSP GL DODGE GL ROBIN GL 

Chemical type- 2 3 4 5 6 7 

Si02 50.31 50.42 51.32 52.36 52.54 49.72 

Al203 12.24 12.08 12.77 12.44 14.07 16.06 

FeO 15.37 15.91 14.95 15.08 12.39 10.83 

MgO 4. 31 3. 85 3.90 3.51 5.31 7. 71 

CaO 9.13 8.56 8.39 8.05 9.74 11.39 

Na20 2. 73 2.88 2.95 2.89 3.04 2.51 

K20 1.19 1.35 1.44 1.56 0.76 0.44 

Ti02 3.92 4.18 3.58 3.51 1. 76 1.12 

P205 0.80 0. 78 0.69 0.60 0.39 0.20 

Total 100.00 100.01 99.99 100.00 100.00 99.98 

Table 12. Corrected and normalized major-oxide chemistry of naturally quenched glass from the Saddle Mountains 

[Geochemical units listed in approximate stratigraphic order, see table 1. Chemical type names for glasses correspond to the chemical 

types for whole rocks. Data are averages computed from original data given in Wright ( 198 8) ] 

Geochemical 

unit------- LM GL GOOSE GL INDIAN GL MARTIN GL BASIN GL BUFORD GL EM GL POMONA GL WEIPE GL ESQUAT GL SPRAGE GL NEW GL ASOTIN GL 

Chemical type- A B c D E F G H I K N 0 p 

Si02 51.68 48.17 49.55 48.25 47.47 55.15 51.71 52.98 52.17 54.88 49.63 49.76 53.60 

Al203 11.61 10.96 11.54 12.62 11.55 12.47 11.81 13.74 13.52 12.72 11.99 14.96 14.09 

FeO 15.96 18.33 16.59 15.88 17.36 13.71 16.12 11.90 12.66 14.02 15.99 11.3 8 11.66 

MgO 3. 35 3.77 3.84 5.29 4.61 3.11 3.56 5.46 5. 71 3.07 4.46 7.04 5.00 

CaO 8.16 9.02 8.95 10.13 9.90 7.57 8.29 10.26 10.31 7.07 9.43 11.58 9. 75 

Na20 2. 86 2.55 2.68 2.47 2.50 3.06 2.54 2.46 2.68 2.72 2.73 2.37 2.80 

K2o 1. 92 1. 34 1.39 0.81 1.00 1. 84 1.43 0.85 0.58 1. 92 1.10 0.44 0.70 

Ti02 3. 88 4.09 4.56 3.80 4.62 2. 73 4.01 2.10 2.13 3.24 3.91 2.04 2.04 

P205 0.59 1. 77 0.90 0.76 0.99 0.37 0.53 0.25 0.23 0.37 0.75 0.44 0.35 

Total 100.01 100.00 100.00 100.01 100.00 100.01 100.00 100.00 99.99 100.01 99.99 100.01 99.99 

Geochemical 

unit------- LAP GL WILBUR GL UM GL 

Chemical type- R T 

Si02 54.69 55.41 56.10 

Al203 13.48 13.45 13.23 

FeO 12.20 12.26 12.41 

MgO 4.07 3.30 2.39 

CaO 8.28 7.53 6.05 

Na20 2.69 2. 83 3.21 

K2o 1. 77 2.26 3.03 

Ti02 2.34 2.42 2.56 

P205 0.48 0.53 1.02 

Total 100.00 99.99 100.00 

38 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
Table 13. Summary of chemical chracteristics for geochemical units in the Yakima Basalt Subgroup 

[Geochemical units listed in approximate stratigraphic order, see table 1; differences from most similar units indicated 

by: >, greater content in unit labeled in column 1; <, smaller content in unit labeled in column 1; differences based on 

MgO variation diagrams. LREE, light rare-earth elements; HREE, heavy rare-earth elements; Eu*, europium anomaly (+ or -) 

Diagnostic oxides and elements are those that stand out on the MgO variation diagrams. Sources of data for 87 sr; 86 sr 

ratio: a, Carlson (1984a); b, Carlson and others (1981); c, Nelson (1980); d, J. Arth (unpublished data); e, McDougall 

(1976) l 

Geochemical 

unit 

LM 

GOOSE 

INDIAN 

MARTIN 

BASIN 

BUFORD 

ELEPHANT 

POMONA 

VC WEIPE 

ESQUAT 

RBESQUAT 

FS IC 

SLIP 

LEWORCH 

SPRAGUE 

SWSPRAG 

NEW 

SWNEW 

ASOTIN 

VCASOT 

SWHUN'IZ 

HUNTZ 

VCLAP 

EAGLE 

WILBUR 

UMATILLA 

UMFRAC 

PHUMTIL 

PH SOPHER 

Most similar unit (differences) Diagnostic oxides and 

By major oxides By trace elements elements 

LOLO INC (>K20,Cs,Nb,Ta, 

Th,U ,LREE; <Sc,HREE) 

Unique 

MARTIN (<MgO) 

Unique 

DODGE (<Na20; >Ti02,LREE) 

ROBIN ( <MgO) 

FS IC 

GR INC,( <Na20,Sc; 

> Ti02,P20 5,LREE) 

LOLO INC (>MgO; <K20) 

POMONA ( <CaO; >K20) 

High Low 

Saddle Mountains Basalt 

LOLO INC ( <Cr) 

Unique 

MARTIN 

Unique 

GR INC (>Hf,Ta,Th,U, 

LREE,HREE; <Sc,Sr) 

Nb Sc 

FeO,Hf,Ta,P20s, SiOz,Co 

Nb, Y,Zn,REE 

Th 

ROSALIA (>Co,Hf,Nb,Cu,Ni; FeO, Ti02 

<Ba,Rb,Sr,HREE 

Ba,Rb 

DODGE (<Cr,Sr,Sc; >Ta,Hf) 

ROBIN (<Sr,Sc; >Ta,Th, 

Hf,LREE) 

FS IC (>Th) 

FS INC (>Co,Nb) 

GR INC (>Co,Hf,Ta,Th; 

<Cr,<Sr) 

LOLO INC (<Cr,Rb,Sr; 

>Ba,Hf,Nb,Ta,Zr,LREE, 

HREE,-Eu*) 

ROBIN (>Hf,Nb,Sc,LREE; 

<Rb,Th) 

POMONA (>Ba,Cr,Th, 

LREE; <Cs,Sc) 

DODGE (>Ba,Nb,Rb,Ta, 

Th,LREE,HREE,Ni; <Cr, 

<Hf<Sc,<Zr,<Cu) 

GR INC (>Ba,Hf,Ta,Th, 

Zr,LREE,HREE; <Sr,Sc) 

SHUMAKER (>Ba,Co,Hf, 

Ta,Th,Zr,LREE; <Cs,Sr, 

Sc,HREE) 

PH UMTIL (<Sc,Rb) 

Th, Ta 

Ta 

FeO, TiOz,P205, 

Nb,Ta,Sc,REE 

Ba,Hf,Zr,Eu 

Ba,Cr 

Ba,Cr 

Sc 

Sc 

Sc 

Sc 

Co,Cr 

.71087(a) 

.71076,.71094(c) 

.70769(d) 

. 70780(a),. 70762(d) 

. 70764(a),. 70770(b ), 

.70785,.7076(d) 

. 70782(a),. 70774(d) 

.70762(b) 

.70807 ,. 70772(c) 

. 70788-. 70829(e) 

. 70750(b),. 707 80(c) 

. 70761-. 70784(e) 

. 71317(a),. 71448(b) 

. 714 71,. 71449(e) 

.71310(e) 

.70755(a) 

.70884(a) 

. 71047,. 71063(a) 

. 70892(b) 

.70935(e) 

Tables and Figures 39 
Table 13. Summary of chemical chracteristics for geochemical units in the Yakima Basalt Subgroup~ontinued 

Geochemical 

unit 

PV 

LOLO INC 

ROSALIA 

PHPOWAT 

ROZA 

FSANOM 

FS INC 

SHUMAKER 

PHSHUM 

SWLOOK 

OODGE 

ROBIN 

GRINC 

Most similar unit (differences) 

By major oxides By trace elements 

Unique 

LM (see above) 

LOLO INC ( <MgO; > TiO~ 

ELEPHANT (>P20 5) 

Wanapum Basalt 

ROZA (>Cr) 

ELEPHANT (>Ba,Rb,Sc; 

<Nb,Ta) 

SHUMAKER (>P20 5) SHUMAKER(<Sc; >REE) 

FS INC (>MgO) FS INC 

FS INC (<FeO; >CaO,Ti02,P20s) FS INC (>Ba,Ta,Hf,Th,Zn, 

Sc,REE) 

ROZA(<MgO) ROZA 

SHUMAKER (<P20s) 

GRINC 

ASOTIN (see above) 

GR INC (>Ba,Hf,Nb,Ta,Y,Sc, 

HREE; <Cr,Cs,Rb,Th) 

SHUMAKER ( <Ba,Hf,Nb,Sc; 

>HREE) 

GR INC (>Cr,Sc; <Th) 

Grande Ronde Basalt 

Diagnostic oxides and 

elements 

High Low 

CaO,Cr,Sc FeO,KzO,Co .7052l(a) 

Co 

MgO 

Si02,Cs,Rb 

Sc .70506(a),.70439(c) 

Cr .70507(a), 

Cr 

Cr 

Rb,REE,Cr 

Ti02.P20s. 

Ta,REE 

.70538,. 70558(e) 

. 70517 (b),. 70498(c) 

.70545(e) 

.70510,.70520(b) 

. 70517(a),. 70530 

.70559(e) 

.7048l(a) 

.70546(a) 

.70435(a) 

. 70438(a) 

. 70489-. 70504(a) 

. 70438-. 70507(b) 

. 70440-. 70606(e) 

.70454-. 70552(c) 

40 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
Table 14. Relation between stratigraphic position and chemistry, additional flows for which chemical data are available, 

Columbia River Plateau 

[MP, magnetic polarity as determined in the field using a fluxgate 

magnetometer: N, normal; R, rever sed, T, transitional J 

Formation 

Member 

Flow 

Informal name 

SADDLE MOUNTAINS BASALT 

Unclassified flows in Idaho 

[Clearwater Embayment; Craigmont, 

Swamp Creek, Icicle Flat, and 

Grangeville Members of Camp 

(1981)) 

W ANAPUM BASALT 

Basalt of Peary Creek3 (Camp, 1981) 

Basalt of Potlatch4 (Camp,1981) 

UNCLASSIFIED 

Local flows in NE Oregon (basalts 

of Powder River of Hooper(1984); 

mapping of W.T. Taubeneck, D.A. 

Swanson, T.L. Wright, and P.R. 

Hooper) 

Age 

(Ma) 

11.6 

13.8-9.5 

MP 

N 

N 

N 

R 

N 

N 

N 

N 

N 

N 

N 

N 

N 

N 

N 

Geochemical 

unit 

VCCRAIG1 

VCSWAMP1 

VC IFLAT1 

VCGRNGE1 

VCFEARY1 

VC POT2 

WT NEPH2 

WT ANDES2 

WT JONES2 

WTSUGMT2 

WTSPRMT2 

WTWBRMT2 

PH EDENl 

WTOBHTII 

WT OBLTII 

1 Chemistry falls within the fields defined for the Yakima Basalt Subgroup 

2 Chemistry falls outside of the fields defined for the Yakima Basalt 

Subgroup 

3 Included in Frenchman Springs Member 

4 Included in Onaway Member of Camp (1981) 

Tables and Figures 41 
Table 15. Average chemical composition of additional analyzed flows of table 14 

[Chemical types listed in approximate stratigraphic order, see table 14. Trace elements followed by X analyzed by X-ray 

fluorescence; all others analyzed by instrumental neutron activation. n. a., not analyzed Data from which these average compositions 

are calculated are given in Wright (1988)] 

Geochemical 

unit--------WT NEPH WT ANDES WT JONES WT SUGMT WT SPRMT WT WBRMT PH EDEN WT OBHTI WT OBLTI VC CRAIG VC SWAMP VC IFLAT VC GRNGE 

Chemical type- A B c D E F G H J K M 

Major oxides (weight percent) 

Si02 43.71 59.31 62.89 53.68 51.14 53.56 52.07 50.80 50.69 52.77 51.74 52.06 53.38 

Al203 15.26 18.01 19.32 17.09 16.10 17.45 14.28 16.76 17.41 14.73 14.91 16.01 16.21 

FeO 15.58 5.97 3.36 7.99 9.18 7.63 13.96 9.87 9.37 13.82 12.93 11.54 8.78 

MgO 7.97 3.12 2.43 3.78 4.98 4.43 3.52 8.86 8. 11 3.83 4.89 5.36 6.62 

CaO 9.00 6. 31 6.56 8.39 9.32 8.69 7.44 9.34 10.78 7.12 8.53 9.56 10.57 

Na20 4.32 4.63 4.29 4.33 4.24 4.66 2.58 2.47 2.36 2.73 2.96 3.12 2.55 

K20 0. 71 1. 78 1.09 2.39 2.29 1. 70 2.24 0.47 0.37 1.74 1.15 0.78 0.68 

Ti02 3.06 0.97 0.45 1.85 2.08 1. 56 2.75 1.44 1.02 2.96 2.73 1.46 1.36 

P205 0.84 0.49 0.25 1.05 1.16 0.83 1.39 0.42 0.28 0.53 0.39 0.37 0.21 

MnO 0.22 0.13 0.11 0.16 0.15 0.15 0.25 0.18 0.17 0.19 0.22 0.26 0.17 

Total 100.67 100.72 100.75 100.71 100.64 100.66 100.48 100.61 100.56 100.42 100.45 100.52 100.53 

Trace elements (parts per million) 

Ba 294 848 592 1234 1088 776 17 88 334 272 715 549 414 311 

BaX 198 821 n.a. n.a. 711 n.a. 1774 428 245 n.a. n.a. n.a. n.a. 

Co n.a. n.a. n.a. n.a. n.a. n.a. n.a. 46.5 n.a. n.a. n.a. n.a. n.a. 

Cr 85.1 46.8 24.1 33.0 60.0 104.4 34.8 363.5 32.0 7.4 38.1 82.2 133.0 

Cs n.a. 0.42 0.82 0.60 0.36 0.58 0.81 0.20 n.a. 0.68 0.67 n.a. n.a. 

Hf 1. 73 3.05 2.05 4.03 3.11 3.00 10.80 2.18 1. 70 6.08 5.41 2.60 3.21 

NbX 6.0 n.a. n.a. n.a. 20.0 n.a. 34.0 14.0 n.a. n.a. n.a. n.a. n.a. 

Rb n.a. 16.0 17.5 20.8 13.0 14.0 52.8 15.7 23.9 41.7 23.7 n.a. 24.0 

RbX n.a. 12.5 n.a. n.a. 36.0 n.a. 49.0 10.0 8.0 n.a. n.a. n.a. n.a. 

SrX 980 1012 n.a. n.a. 2443 n.a. 238 479 467 n.a. n.a. n.a. n.a. 

Ta 0.45 0.57 0.46 0.60 0.52 0.45 2.37 0.51 0.37 1.67 1.53 0.52 0.97 

Th n.a. 1. 75 2.05 3.07 1.83 2.58 7.73 0.85 0.61 7.15 3.15 1.05 2. 85 

u n.a. 0.75 0.73 0.83 0.63 0.65 1.67 0.37 n.a. 1.47 1.03 0.49 0. 82 

YX 13.5 20.5 n.a. n.a. n.a. n.a. 59.0 27.0 21.0 n.a. n.a. n.a. n.a. 

Zn 133 86 65 121 138 110 152 95 88 149 160 156 123 

Zr n.a. 142 117 163 135 173 487 98 81 243 420 160 147 

ZrX 67 125 n.a. n.a. 122 n.a. 480 136 81 n.a. n.a. n.a. n.a. 

Sc 25.8 13.5 8.6 16.1 15.9 16.6 27.1 28.1 32.6 26.1 33.8 39.5 33.0 

La 16.7 30.5 14.5 52.3 46.7 37.9 58.7 13.2 8.4 42.9 32.3 13.3 19.9 

Ce 44.3 51.1 25.8 112.8 105.0 80.4 116.8 27.2 18.4 81.5 56.4 26.7 36.7 

Nd 32.4 28.3 12.5 62.2 57.6 43.2 63.5 17.2 12.5 44.9 34.5 19.5 19.2 

Sm 6.9 5.3 2.3 &..8 8.8 7.0 13.7 3.8 2.9 8.8 7.8 4.5 4.7 

Eu 2.11 1.52 0.75 2.47 2.33 1. 86 4.42 1.26 0.95 2.41 2.24 1.32 1.25 

Gd 4.50 4.50 2.20 6.40 5.80 5.30 14.10 3.70 2.70 8.90 8.00 4.70 4.70 

Tb 0.83 0.60 0.28 0.70 0.68 0.58 2.08 0.69 0.57 1.25 1.36 0.84 0.72 

Yb 1.12 1. 76 0.90 1.32 I. 10 1.22 5.79 2.22 2.03 3.99 4.15 3.34 2.50 

Lu 0.14 0.25 0.12 0.18 0.17 0.19 0.83 0.33 0.33 0.67 0.74 0.67 0.46 

Cu n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 

Ni n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. n.a. 

Normalized major-oxide contents (weight percent) 

Si02 43.42 58.89 62.42 53.30 50.81 53.21 51.82 50.49 50.41 52.55 51.51 51.79 53.10 

Al203 15.16 17.88 19.18 16.97 16.00 17.34 14.21 16.66 17.31 14.67 14.84 15.93 16.12 

FeO 15.48 5.93 3.33 7.93 9.12 7.58 13.89 9.81 9.32 13.76 12.87 11.48 8.73 

MgO 7.92 3.10 2.41 3.75 4.95 4.40 3.50 8.81 8.06 3. 81 4.87 5.33 6.59 

CaO 8.94 6.26 6.51 8.33 9.26 8.63 7.40 9.28 10.72 7.09 8.49 9.51 10.51 

Na20 4.29 4.60 4.26 4.30 4.21 4.63 2.57 2.46 2.35 2.72 2.95 3.10 2.54 

K20 0. 71 1.77 1.08 2.37 2.28 1.69 2.23 0.47 0.37 1. 73 1.14 0.78 0.68 

Ti02 3.04 0.96 0.45 1.84 2.07 1.55 2.74 1.43 1. 01 2.95 2.72 1.45 1.35 

P205 0. 83 0.49 0.25 1.04 1.15 0.82 1.3 8 0.42 0.28 0.53 0.39 0.37 0.21 

MnO 0.22 0.13 0.11 0.16 0.15 0.15 0.25 0.18 0.17 0.19 0.22 0.26 0.17 

Total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 100.00 

42 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Croup, Washington, Oregon, and Idaho 
Table 15. Average chemical composition of 

additional analyzed flows of table 14-

Continued 

Geochemical 

unit--------VC FEARY VC POT JOSEPH IMNAHA 

Chemical type- N 0 t 

Major oxides (weight percent) 

Si02 51.70 48.41 55.40 47.80 

Al203 14.41 16.82 15.05 15.32 

FeO 14.12 12.96 12.43 10.61 

MgO 4.08 5.04 3.24 12.02 

CaO 7.66 7.45 6.73 10.19 

Na20 3.00 3.52 2.82 2.14 

K20 1.60 1.69 1.72 0.22 

Ti02 3.25 3.84 2.36 1.25 

P205 0.40 0.72 0.47 0.09 

MnO 0.18 0.18 0.20 0.18 

Total 100.40 100.63 100.42 99.82 

Trace elements (parts per million) 

Ba 550 367 857 140 

BaX 521 360 n.a. 89 

Co n.a. 42.9 n.a. 49.1 

Cr 20.7 8.9 6.5 861.5 

Cs 0.83 0.37 1.27 n.a. 

Hf 5.38 6.84 4.85 1.73 

NbX 24.0 42.0 n.a. 10.0 

Rb 42.0 29.8 43.5 n.a. 

RbX 45.0 26.0 n.a. n.a. 

SrX 245 540 n.a. 384 

Ta 1. 70 3.61 0.90 0.26 

Th 7.10 3.13 5.39 0.29 

u 1. 76 1.21 1.64 n.a. 

YX 45.0 27.0 n.a. 17.0 

Zn 152 129 134 89 

Zr 237 281 227 n.a. 

ZrX 190 298 n.a. 82 

Sc 29.1 19.1 30.6 26.9 

La 35.9 37.4 26.9 5.1 

Ce 64.2 74.8 52.3 12.9 

Nd 36.2 41.3 30.1 10.5 

Sm 7.5 9.2 7.5 2.9 

Eu 2.11 2.69 1.96 0.93 

Gd 8.3 7.8 7.5 2.9 

Tb 1.09 1.19 1.07 0.43 

Yb 3. 73 2.29 3.83 1.69 

Lu 0.66 0.39 0.58 0.27 

Cu n.a. n.a. n.a. n.a. 

Ni n.a. n.a. n.a. n.a. 

Normalized major-oxide contents (weight 

percent) 

Si02 51.49 48.11 55.17 47.89 

Al203 14.35 16.71 14.99 15.35 

FeO 14.06 12.88 12.38 10.63 

MgO 4.06 5.01 3.23 12.04 

CaO 7.63 7.40 6.70 10.21 

Na20 2.99 3.50 2. 81 2.14 

K20 1.59 1.68 1.71 0.22 

Ti02 3.24 3.82 2.35 1.25 

P205 0.40 0.72 0.47 0.09 

MnO 0.18 0.18 0.20 0.18 

Total 100.00 100.00 100.00 100.00 

Tables and Figures 43 
Table 16. Ratios of incorpatible trace elements in additional analyzed flows of table 14 

[Geochemical units listed in approximate stratigraphic order, see table 14. n. a., not analyzed] 

Geochemical 

unit--------WT NEPH WT ANDES WT JONES WT SUGMT WT SPRMT WT WBRMT PH EDEN WT OBHTI WT OBLTI VC CRAIG VC SWAMP VC IFLAT VC GRNGE 

Chemical type- A B c D E F G H J K L M 

KIRb n.a. 11.82 n.a. n.a. 5.28 n.a. 3.79 3.90 3. 84 n.a. n.a. n.a. n.a. 

KITh n.a. 84.44 44.14 64.63 99.99 54.70 24.06 45.90 50.35 20.20 30.31 61.67 19.81 

KIP 1. 61 6. 91 8.29 4.33 3. 75 3. 89 3.06 2.13 2.51 6.24 5.61 4.01 6.16 

KIBa 29.77 18.00 n.a. n.a. 26.74 n.a. 10.48 9.12 12.54 n.a. n.a. n.a. n.a. 

KISr 6. 01 14.60 n.a. n.a. 7. 78 n.a. 78.13 8.15 6.58 n.a. n.a. n.a. n.a. 

RbiSr n.a. 1.24 n.a. n.a. 1.47 n.a. 20.59 2.09 1. 71 n.a. n.a. n.a. n.a. 

Hf/Th n.a. 1. 74 1.00 1.31 1. 70 1.16 1.40 2.56 2. 79 0.85 1.72 2.48 1.13 

Hf/Ba 8. 70 3. 70 n.a. n.a. 4.40 n.a. 6.10 5.10 6.90 n.a. n.a. n.a. n.a. 

Hf/Zr 25.80 24.40 n.a. n.a. 25.50 n.a. 22.50 16.00 21.00 n.a. n.a. n.a. n.a. 

Hf/Ta 3.84 5.35 4.46 6.72 5.98 6.67 4.56 4.27 4.59 3.64 3.54 5.00 3. 31 

Hf/La 10.36 10.00 14.14 7. 71 6.66 7.92 18.40 16.52 20.24 14.17 16.7 5 19.55 16.13 

ThiBa n.a. 2.10 n.a. n.a. 2.60 n.a. 4.40 2.00 2.50 n.a. n.a. n.a. n.a. 

LaiSm 1.48 3.51 3.84 3.62 3.23 3.30 2.61 2.12 1. 77 2.97 2.52 1. 80 2.58 

LaiYb 9.85 11.44 10.64 26.16 28.03 20.51 6.69 3.93 2.73 7.10 5.14 2.63 5.26 

Geochemical 

uni t--------vc FEARY VC POT JOSEPH IMNAHA 

Chemical type- N 0 jf 

KIRb 2.95 5.40 n.a. n.a. 

KITh 18.71 44.82 26.34 62.98 

KIP 7.61 4.46 6.92 4.65 

KIBa 25.49 38.97 n.a. 20.52 

KISr 54.21 25.98 n.a. 4.76 

RbiSr 18.37 4. 81 n.a. n.a. 

HfiTh 0. 76 2.19 0.90 5.97 

Hf/Ba 10.30 19.00 n.a. 19.40 

IIfiZr 28.30 23.00 n.a. 21.10 

Hf/Ta 3.16 1. 89 5.39 6.65 

Hf/La 14.99 18.29 18.03 33.92 

Th/Ba 13.60 8. 70 n.a. 3.30 

La/Sm 2.92 2.48 2.19 1.07 

La/Yb 6.36 10.78 4.64 1.99 

44 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
Table 17. Summary of chemical characteristics of additional flows for which chemical data are available, Columbia River 

Plateau 

[Chemical analyses on which this table is based are given in table 15; geochemical units listed in approximate 

stratigraphic order, see table 14. The chemistries of these flows are compared with chemistries of basalts 

erupted in Saddle Mountains, Wanapum, or Grande Ronde time, using MgO variation diagrams (Fig. 4). Differences 

from most similar units indicated by: >, greater content in unit labeled in column 1; <, smaller content in unit 

labeled in column 1; differences based on MgO variation diagrams. LREE, light rare-earth elements; HREE, heavy 

rare-earth elements; Eu*, europium anomaly (+ or -). Diagnostic oxides and elements are those that stand out on 

the MgO variation diagrams. Sources of data for 87sr;86sr ratio: a, Carlson (1984a); b, Carlson and others 

(1981); c, Nelson (1980); d, J. Arth (unpublished data); e, McDougall (1976). The column labeled 'comment' gives 

a qualitative assessment of chemical classification and possible petrologic connections to units closely related 

in time. See text for discussion of speci fie examples] 

Geochemical 

unit 

WTNEPH 

WT ANDES 

WT JONES 

WTSUGMT 

WTSPRMT 

WTWBRMT 

PH EDEN 

WTOBLTI 

WTOBLTI 

VCCRAIG 

VCSWAMP 

VC IFLAT 

VCGRANGE 

VCFEARY 

VCPOT 

Most similar unit (differences) Diagnostic oxides and 

By major oxides elements 

unique 

unique 

WT ANDES ( <MgO) 

unique 

unique 

WT SUGMT ( <K20) 

UMATILLA (>MgO, 

P205,Y,REE) 

WT OBHTI (> Ti02) 

ROBIN (>P20s) 

ESQUAT 

unique 

GR INC ( <Si02; 

>Al203,P20s) 

DODGE ( <MgO) 

GR INC (>MgO,Ti02; 

<Na20) 

FS IC 

unique 

By trace elements comment 

High Low 

unique 

unique Si02,Sr 

Na20 

WTANDES Si02,Na20 

unique Na20,K20 

unique Na20,K20,Sr 

WT SUGMT ( <Hf,REE) Na20 

UMATILLA (<Ba; >Hf, 'FeO',P20s 

Nb,Ta,Y,REE) Ba,Hf,Rb,Ta 

Th,Zr,REE 

ROBIN (>Ba,Cr,Rb,Th) 

ESQUAT (<Th,<Sc; 

> LREE,HREE) 

unique 

GR INC (<Hf,Ta,Th,U, Sc 

LREE;>HREE 

DODGE,( <Hf,LREE; 

>HREE) 

GR INC (>Hf,Rb,Th,Ta, Si02 

REE; <Sc) 

FS IC 

unique 

Si02,Cr,Nb, 0.70343(b) 

Rb (n.d.) 

The only nephelinenormative basalt (basanite) 

in the Columbia Plateau. 

Sc 

Sc 

Sc 

Hf,Sc 

Sc 

S i02,Al203, 

Na20 

Sc 

Th 

Ti02,Hf,Ta, 

Th,Zr,LREE 

Si02,CaO, 

Ba,Cr,Sc 

0.70354(b) The only true andesites in 

the Columbia River Plateau 

More evolved andesite, 

related to WT ANDES 

Parental to WT ANDES? 

Low silica 'andesite'-

related to WT NEPH? 

Olivine basalt 

0.70353(b) Olivine basalt 

Flatter REE pattern than 

other units of Saddle 

Mountains Basalt. 

Most like GR LH 2 N2 type 

Magnetic polarity opposite 

to that of FS IC. 

Columbia River(?) Basalt 

Group. Resembles ROZA in 

field appearance. 

Tables and Figures 45 
A 2 4 o. o .----.---.--.--.-----.-----.---.-------,----, 

200.0 j ~ 3.5 

16o.o I 

z 120.0 

80.0 

z ::J 

0 u ::J 

...J 

~ 

a: 

w 

Q.. 

40.0 

0.0 

40.0 

0.0 

50.0 

~ 40.0 a: (.) 

~ (/) 30.0 

~ 

I-' 

z 

w I- c:: z N 

0 

u 

1-

z 

w X 

~ U5 ...J 

w 

20.0 

250.0~ 

150.0 

50.0 

500.0[ 

400.0 

300.0 

200.0 

2 

I 

: : ~~ l:;;dlil- :: : : ~ 

: : >~~~: : : j 

3.0 

2.5 

2.0 

1.5 

~~-~~~~-~-~-~~-~1.0 

.-----.---.--.----,--.-.--.--.-~4.0 

3.5 

3.0 

2.5 

2.0 

1.5 

1.0 

0.5 

N 

0 

f= 

0 N 

~ 1-

z 

w 

u 

a: 

w 

Q.. 

II 

(!) 

jjj 

8 il:~ t : ' I~~~~~: : : l· ~:~-~X : : r~~~ 

3: 

~ 

t-=' 

z 

w 

1-

z 

0 ~u 

co w z 0 

x 

0 

1-

z 

w 

u 

a: 

w 

Q.. 

II 

Q 

w 

~ Ill 

~ ~ I-' Q.. 

z 

w 

1-

z 

0 

u 

w 

Cl 

§ 

1.5 

1.0 

0.5 

0.0 

~;(, 10.0 

9.0 

8.0 

7.0 

6.0 

~~-~-~~-~-~-~~-~5.0 

0 

co 

u 

9 8 7 6 5 4 3 2 0 9 8 7 6 5 4 3 2 

MgO CONTENT, IN WEIGHT PERCENT 

Figure 4. Major-oxide and trace-element chemistry of units 

of the Yakima Basalt Subgroup, presented as MgO variation 

diagrams. Diagrams scaled so that symbol size reflects 

approximately two standard deviations. Plotted data are 

averages of at least two samples from each geochemical 

unit; analyses recalculated to 100 percent dry weight with 

total iron expressed as FeO (see tables 3-5). Except where 

otherwise noted, symbols refer to chemical types identified 

in table 3 (Grande Ronde Basalt), 4 (Wanapum Basalt), 

and 5 (Saddle Mountains Basalt). A, Grande Ronde Basalt, 

major oxides and compatible trace elements. Symbol # is 

the joseph volcanics of Kleck (1976). 8, Grande Ronde 

Basalt, incompatible trace elements. C, Grande Ronde 

Basalt, selected trace-element ratios. D, Wanapum Basalt, 

46 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Croup, Washington, Oregon, and Idaho 
B I . 4 

::J I. 0 .....J 0.6 

0.2 

5.0 

~ 3. 0 

.0 

~ 

1.0 

2.5 

0.0 

5.5 

4.5 

::J 3. 5 w 2.5 

1.5 

0.5 

~ ~ ~ ~ ~ oi .-----r: --r-: -,"'T"; --,---.,-----.-----.-----.------, 

~ 

a: 

w 

a.. Q) 

~ u a: 

90.0 

60.0 

30.0 

~ 

~ 

.,_..: 

z 

w 

....... 

120.01 

0 . 0 ,____._ _ _.L_ _ _.______. _ _..L..,_...,l__..L..,___J, _ __J 

z 

0 m u .....J 

....... 

z 

w 

~ 

w 

.....J 

w 

70.0 

60.0 

50.0 

40.0 

30.0 

20.0 

10.0 

0.0 

soo.o.--~--r----r-~~~--,---.,-----.-~ 

X 

N 

400.0 

200.0 

0.0 

BOO. 0~ 

N 400. o~ 

0.0 

: : l 

: : l 

1

8.0 

6.0 

LJ.O 

2.0 

,____._ _ _.L_ _ _.______.~~-...J,_--..1...,_~--~o.o 

I

ILO 

3.0 

2.0 

1.0 

,____._ __ _.L_ _ _.______.~~--~-~~--~o.o 

,____._ _ _.L_ __ 

,: 

_.__~~~--...J,_--..L..,___J, 

L~~ ~ .. : : : __ ~lo.o F~:~ 

,; +~&: ~ J8:8 ~--'----L~~~==~--~--~~--~Io.o 

I

ll. 0 

9.0 

7. 0 

5.0 

3.0 

'----'----L--_.______.~~--...J,_--~-J----' 1.0 

f ; ~iW: 1 f:8 '-----'----L--~~~~--~--~-J----'0.0 

,...----,----.-----r-~.--~---,----.,----,--~ 4500. 0 

..c: 

~ 

X 

.0 

a: 

.0 

a: 

X 

.0 

z 

-I 

1/) 

u 

4000.0 

3500.0 

3000.0 

2500.0 X 

m 2000.0 cc 

1500.0 

1000.0 

500.0 

L__..J.. __ _.L_ __ _.__------'~~--~--~------'----' 0. 0 

,...----,----.----r--~.--~---,----~---r----, 4500. 0 

4000.0 

3500.0 

3000.0 

2500.0 m 

a:l 2000.0 

1500.0 

1000.0 

500.0 

,____._ __ _.L_ __ _.__~~~--~--~~--~o.o 

9 8 7 6 5 3 2 0 9 8 7 6 5 3 2 0 

MgO CONTENT, IN WEIGHT PERCENT 

major oxides and compatible trace elements. E, Wanapum Basalt, incompatible trace elements. F, Wanapum 

Basalt, selected trace-element ratios. G, Saddle Mountains 

Basalt, major oxides and compatible trace elements for 

geochemical units with relatively high Si02 and low FeO 

and Ti02 (that is, of Grande Ronde affinity). H, Saddle 

Mountains Basalt, incompatible trace elements for units of 

Grande Ronde affinity. /, Saddle Mountains Basalt, selected trace-element ratios for units of Grande Ronde 

affinity. }, Saddle Mountains Basalt, major oxides and 

compatible trace elements for geochemical units with relatively low Si02 and high FeO and Ti02 (that is, of Wanapum affinity). K, Saddle Mountains Basalt, incompatible 

trace elements for units of Wanapum affinity. L, Saddle 

Mountains Basalt, selected trace-element ratios for units of 

Wanapum affinity. 

Tables and Figures 47 
c 9.0 

..c 7. 0 

>- 5. 0 -ro 

.....J 3. D 

I. 0 

lB. 0 

16. 0 0 

20.0! 

g 14 0 

~ 

co 

co 

:c 

12. 0 

I 0. 0 

8.0 

1- 6. 0 

4.0 

2.0 

C B 

{hr{;lc Wf cll!rn a _,_.. 2. 

r: : I : : 12 ~~,: : : I ~ 8.0 

10.0=, 

~ 6.0 12 

(fJ i 4.o 

0 2.0 

~ a: 

1- 0 

z 0 w 0 

~ X 

~ N w i 

, 0 I 30.0 

28.0 

26.0 

24.0 

2?.0 

20.0 

t~V' ' 'l 

2 2. 0 r---r---.--...------.---,---.--r------r---, 

0 17.0 

0 

0 

~ 12.0 co 

co 

i 7.0 

2.0 

l 7. 0 0 

0 

..... 

-2 J 2. 0 (fJ 

:0 

a: 7.0 

2.0 

8 

X 

[ w_l lJ~ ~ft 0 B 

I 

: : l 

0 9 

75.0 

65.0 B 

55.0 

U5 45.0 :;;::: 

35.0 

25.0 

2 I 15.0 

L_~-~-~~--L-~-L-~--~5.0 

,..-------,-_,...-~--,----.-....,--,------,---, 3 3. 0 

c c 

E& X 

0 ~~ Cr~R ~ i; 0 

2 

29.0 

25.0 

21.0 co 

co 

17.0 :;;::: 

13.0 

9. 0 

L,_~ _ __j_ _ _.___~c_____,L__-l....__.!,___J.._.....J 5. 0 

,..-----,-_,...--~--,-----.:=--.....---.------.--, 14. 0 

C~ux 12.o 

10.0 

8. 0 Q.. 

6. 0 :;;::: 

12 2 I 4. o 

2.0 

L._~ _ __J,___~___J,--_L __ ~ __ L___J__.....J 0. 0 

...--------.---.--...----.---,--....,--,------,----, so. 0 

2 

4 

8 2 

45.0 

40.0 

35.0 5 

0 

~ 

..r:::. 

30.0 1:::: 

~ 

25.0 

20.0 

1

13.0 

11.0 5 9. 0 c) 

1.0 :E- 5. 0 a: 

3.0 ~ 

l.O 0 

MgO CONTENT, IN WEIGHT PERCENT 

Figure 4. Continued. 

48 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
D 2 4 0. Or--o---,----.--.-----.--,---,--.------, ,----,----.,----,---,-------,----,-~~ 3. 8 

200. 0 CF R 

160.0 B Ef 3.3 

z 120.0 J 2.8 

80.0 

40. 0 I B ( R 

0 2. 3 i= 

0. 0 '----'----'-----'--~--H--e ~~ 1.8 

: I B ~FR :g : : I ===J ======~.; 3.5 

: 'I B ~ 'R 0 ~ : : I 

3.0 

2.5 

0 

0~ 2.0 -::2 1-

tz 

w 

u 

a: 

w 

ll.. 

II 

Q 

w 

~ I{) 

z 0 

;:.~ 

z 

w 

1-

z 

0 

u 

w 

0 

§ 

1.0 

B 

0.5 

J 

0 

~ c 

R 

EF H 

F 

1.5 

1.0 

~ J: : : ~ ~ 18.0 0 B fifFR 0~ 15.0 N 

~_..L.__~....L.......:. :....____t_. ---L.-. ______.__________.________, 1 2. 0 <! 

z 

w 

u 

a: 

w 

ll.. 

II 

(9 

w 

~ 

z 

0 . 0 .____.____._____,___.______.____.________.___............___ 1 J : I B ( : R ~ : : 1 4 

~u 7 . 0 ~ 9 8 7 6 5 4 3 2 I 0 9 8 7 6 5 4 3 2 I 0 

MgO CONTENT, IN WEIGHT PERCENT 

Figure 4. Continued. 

Tables and Figures 49 
3500.0 

3000.0 

2500.0 X 

co 2000.0 IXJ 

X 

N 

400.0 

200.0 

0 . 0 ~-----'---~_____L..._..___L__....L..._..-----L---..1 

8 0 0. 0 ,----,------~~-.-------~---.---------.. 

F D IV A H 

I B !if 

1500.0 

1000.0 

500.0 

~--L.-L---L------'------l---1--__.J,.___J 0. 0 

,-----,-----r--,----,------,-------,r---------r----,-----, lj 5 0 0 • 0 

4000.0 

3500.0 

3000.0 

2500.0 N ~0~.0~ co J: : :, ,: ~F :, ~ : : l ~ :~: ~ ! J: : :I ·: ~F :A O ~ : : l !500. 0 

2000.0 m 

Ot 1000.0 

~ ~: ~ t : : :I B > > 0 ~ : : l 1 ----------L__l--1--B ..__(fF ..__A L...---H ~ 500 • 0 - 0.0 

9 8 7 6 5 4 

Figure 4. Continued. 

3 2 1 0 9 8 7 6 5 

MgO CONTENT. IN WEIGHT PERCENT 

4 3 2 1 0 

50 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
F ~ n f J: ' 'I B' ~ 'A 0~ ' l 

l.O 

E 11.o 

~ 

j 1.0 

2 0. 0 r--.---.-.--------.--------,---.-------,--,-----, 

18. 0 

- 16.0 0 g 14.0 

x 12.o 

<a 1o.o 

~ 8.0 

1- 6. 0 

4.0 

2.0 

,, I ! JB.O 

13.0 

0 17.0 

0 

0 

..... 

J 

~ 12.0 J 

en 

i 7.0 

2.0 

I B l 

F A 0~ 

r·o ! J: : :I B: ~:A 0; : : l 0.0 

22. 0 ..----r-----,----r----,--.....---r--r-----r---. 

- 17.0 0 

0 

..... 

)( 

1:' I;?. 0 

en 

:0 

0: 7.0 

2.0 9 6 

0~ 

B Ef'F R 

j :: : 

65.0 

55.0 >-

en 45.0 ~ 

35.0 

25.0 

15.0 

l__....j.J------L--'---_J._------'--L..---'--..l.----' 5. 0 

,.--.....,.-----.,--,--------,--------,---.-----,--,----, 3 3. 0 

29.0 

F 25.0 

H 21.0 co 

ca 

I B t 0 ~ 

F A ~ 

j 17.0 

13.0 

J 

9.0 

.___~----'---'------'-----'--"------'--..____, 5. 0 

.------.---,--.--------,--------,---,-------,--,----, l 4 . 0 

12.0 

10.0 

J I B ~F A 0~ 

8.0 a.. 

6.0 ~ 

11.0 

2.0 

.___~----'---'------'-----'--"-----'--..____, 0. 0 

r---.--.-.--------.--------,---.-----,--,----, 50. 0 

J 

F 

B t A 

F 

ot1 

G 

llS.O 

40.0 

- 35.0 ~ 0 

~ 

..r: 30.0 1:::: 

:::£ 

25.0 

20.0 

MgO CONTENT, IN WEIGHT PERCENT 

Figure 4. Continued. 

Tables and Figures 51 
200.0 p 

a: 

160.0 

z 120.0 

80.0 

40.0 

0.0 

120.01 

80.0 

40.0 

0.0 

I-

~ u 50.0 

40.0 

I a: (J) 

~ 30.0 

z 

I-' 20. 0 

f5 250. 0~ 

~ ~ 150.0F 

0 50.0 u 

I- 400.0f z X ~ c/5 300.0 

UJ 200.0- _J 

UJ 400.01 

300.0 

u 200.0 

100.0 

0.0 

1--

z 

UJ 

u 

a: 

UJ 

CL 

II 

(.9 

UJ 

so. 40.0 0 I 

3 30.0 

20.0 

10.0 

1. 5 

1. 0 

~ 

z 0 

;:=- c{' 

z 

UJ 

1--

z 

0 

u 

UJ 

0 

x 

0 

0.5 

0.0 

Q 

p 

R 

H R F S 

p p Q H RR F s : : : I 

PPgH~~Rl: •: '' l 

p :p Q < Q ~R L ~ S : : : : ~ 

P :p Q H: 1 ~R l ; < : : : l 

p p Q H ~ "\ \ 5 : : : : I 

p: H Q R L F s : : ' I 

L S 

Q 

RR F 

l 

I RR Q 

F 

5 

3.5 

3.0 

N 

2.5 s 

2.0 

1.5 

l___...J.______j_____J________I.____L_J___~__J_____J 1. 0 

.------.----.-----.-----.------,--..-------.------r---.. Lj • 0 

QH 

p p 

L 

s 

3.5 

3.0 

2.5 

0 

2.0 -2 1--

z 

UJ 

1.5 

1.0 

0.5 

u 

a: 

UJ 

a.. 

II 

<.9 

w 

~ 

z 

L__._~--'--_..__---'--_______. _ _.___.____J___.J 0 . 0 !--=" 

z 

UJ 

1-

z 

0 I 

Lj. 5 

4.0 

3.5 

3.0 

2.5 

2.0 

1.5 

0 u ~ UJ 

z 0 

§ 

,------,------,----,------r-------,--.....---.-----r---, 1 2 . 0 

p p H 

Q I 

Q RR L 

F 5 

11.0 

10.0 

9.0 <;6 

8.0 u 

7.0 

6.0 l______!..______j___.J..__-----'---__J__.J.._____.t_______J____.J 5 . 0 

L-~ _P...J.._:P_o __.~_H: _O_RL_: R_L ...J.._~ _s ___J_:_.J.._____.t______l____..J~ l u ~ 

I ppaHqRRL~s : : : 

r·o 59.0 

55.0 ~ 51.0 

47.0 

9 8 6 5 Lj 3 2 0 9 8 7 6 5 Lj 3 2 0 

MgO CONTENT, IN WEIGHT PERCENT 

Figure 4. Continued. 

52 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Croup, Washington, Oregon, and Idaho 
X 

N 

400.0 

R F 

C H I A L p p 

200.0 

0. 0 ~----'--~----'--..______.____----'-----' 

4000.0 

3500.0 

3000.0 

2500.0 X 

co 2000. 0 (IJ 

1500.0 

1000.0 

AR F S 500.0 

PPCH I L l___.....L..__.____L-.J.___.____L.....__..L._.__._____. 0 . 0 

r---r--r--.---.--------,--,r-----r----,----, 4 50 0. 0 

N : ~~: ~~L--..J..._ :ro____,__: 0 ,'------'----' • : s----'--------': .~: ~: l 

4000.0 

3500.0 

3000.0 

2500.0 co 

2000. 0 (IJ 

~ : ~: ~ ~ p .L...__: P C H .L...__: l A.L...__: R l F.~...___: 5 L.__: L.__: l.____: ~: l 1 50 0 • 0 

10.0 - 1000.0 

:J ~: ~~ ,---.---: p g H r--: Q Ar---: R l f.---: 5 .---: .---: r---: ,-----,: l p p 0 H 9 R \ f 500. O 

0 . 0 L_____.L___l___L______..l._____L___._.JL---..L..-_____J________J 0 . 0 

9 8 7 6 5 4 3 2 1 0 9 8 7 6 5 4 3 2 I 0 

MgO CONTENT. IN WEIGHT PERCENT 

Figure 4. Continued. 

Tables and Figures 53 
E ~.o 

~ 

j l.O 

2 0. 0 r-----r----.----.---.---.---..------.----.-----, 

18. 0 

0 16.0 

0 14. 0 0 

..... 

~ 

co 

12.0 

10.0 

~ 8.0 

I- 6. 0 

~.0 

2.0 

Q 

p p 

H L F 

I ffi 5 

2 2. 0 r----.---,-----.-----.--,----.-----,-----r---, 

0 17.0 

0 

0 

..... 

~ 12.0 co 

cc 

~ 7.0 

2.0 

p Q 

p 

H 

L 

s 

f.O ! P :p 0 H: ~ ~ L ; S : : : : l 0.0 

2 2. 0 r-----r----.----.----.--,----.----,-----r---, 

0 17.0 

0 

..... 

~ 12.0 (/) 

::0 

a: 7.0 

2.0 

p 

p 

9 

s 

R 

L 

Q H R 

6 5 0 9 

75.0 

65.0 

55.0 

en ll5.0 ~ 

F S 

R 

R L 35.0 

Q H 25.0 

pP 15.0 

,.-----,.---,---,---.---.---.-------.---.----, 33. 0 

Q 

p p 

H 

R 

R 

F 

L 

s 

29.0 

25.0 

21.0 co 

CD 

17.0 ~ 

13.0 

9.0 

~~-~-~-~-~-~~-~-~s.o 

,.-----,.---,---,--.....--.---..-----.---,----, Ill. 0 

12.0 

10.0 

F S 

L 

B.O Q.. 

6.0 ~ 

ll.O 

2.0 

~~-~-~-~-~-~~-~-~ 0.0 

,.-----,.---,---,---r---r--r------r---r---.. 50. 0 

Q 

Q H 

p 

R 

R 

s 

45.0 

40.0 

5 35.0 ci 

X 

::c 30.0 ~ 

25.0 

20.0 

L___!.P_J,__...i......__.I..._._;L::.,___jF _ _..J... _ __._ _ _.___...L.-___, 15. o 

8 6 5 2 

1

13.0 

11.0 5 9. 0 ci 

7.0 ::E s.o a: 

3.0 ~ 

1.0 0 

MgO CONTENT, IN WEIGHT PERCENT 

Figure 4. Continued. 

54 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
J 240.0.--.---.---,--.---.---.-~--~--~ 

200.0 

160.0 

z 120.0 

80.0 

40.0 

0.0 

(j (j 

M N N M 

tlr (j 0 

B 

0 c 

N 

A 

N 

G 

K J 

J 

3.5 

3.0 

2.5 

2.0 

0 

i= 

120.0.--.---.---.--.---.---.--.--~--~ 1.5 

80.0 

z :J 

0 u 

::J 40.0 ..J 

~ 

a: 

w 

ll.. 

0.0 

50.0 

~ 40.0 a: u 

~ en 30.0 

..... 

z 

w 

u 

a: 

w 

ll.. 

..... 

:I: 

(!) 

jjj 

~ 

~~ .,_.:-ll.. 

z 

w 

..... 

z 

0 

u 

w 

0 

g 

1.2 

0.7 

0.2 

9 

(j 

Cl M 

M 

(j Cl 

8 7 

Figure 4. Continued. 

E C 

N 

0 

N A 

6 5 

B 

4 

T 

~~--~--~--~--~--~~--~--~ 1.0 

~-----.---.--.---.---.--.---.--~4.0 

Cl M 

Cl 

Eo 

N 

c 

N 

R 

sG 

T T 

u 

3.5 

3.0 

2.5 

2.0 

1.5 

I. 0 

0.5 

~~--~--~--~--~--~~--~--~ 0.0 

1

4. 5 

4. 0 

3.5 

3.0 

2.5 

2.0 

.-------.----.------.----r----r---.----,,.---.---~ I 2 . 0 

0 Cl 

M 

11.0 

10.0 

9.0 

8.0 

7.0 

T 6.0 ~~--~--~--~--~--~~~~~~ 5.0 

.---.--~-----.-----,----...,..----.---.,,.--.----, 2 0 • 0 

0 

-2 ..... 

z 

L.U 

u 

a: 

L.U 

a.. 

..... 

I 

S2 

w 

~ 

~ 

..... -

z 

w 

..... 

z 

q,o 

ro U 

z ~ 

x 

0 

0 

ro 

u 

15.0 0 

I 0. 0 Lf 

T 59.0 

JJ 

NR ~ (j OM N 1=P C R ~~--~--~--~~~--~~~~--~47.0 

0 55. 0 U5 

51.0 

3 2 0 9 8 7 6 5 4 3 2 0 

MgO CONTENT, IN WEIGHT PERCENT 

Tables and Figures 55 
K 1.4 

:J 1 • 0 

....J 0. 6 

0.2 

6.0 

~ 4.0 

..0 

1-

2.0 

3.0 

0.5 

5.5 

4.5 

:J 3. 5 

w 2.5 

1.5 

0.5 

20.0 

6 ~ 12.0 

j 4.0 

t ~ 0 ,: , •:

0 

c .:, : ~; J :~ , : : j 

~ : 0 H: N :° C N:~ R ~ J :ul T : : 1 ~ 

! : ,,: ',:, c.::.; J :u' < : l 

E 

0 N 

~ 

D 

l l 

u 

~ 150.0,---,---,--,,--,~u-o---.---.---.--~ 

ffi 120.0 a.. Q) 

Cf) u 90. 0 

1-

a:: 

~ 

z 

1-' 

z 

w 

1-

z 

0 <1l u _, 

1-

z 

w 

~ 

w 

_, 

w 

60.0 

30.0 

80.0 

70.0 

60.0 

50.0 

40.0 

30.0 

20.0 

10.0 

H 

Q 0 

H 

0 

E C N ul l 

N D 5J J 

E C N ur T 

N 0 If; J J 

600.0.--.---.---.--.---.---~~--~--~ 

X 

N 

400.0 

200.0 

0.0 

3.0 

:::) I .5 

0.0 

H 

0 

E C N 

N 0 ~J J 

A 

1

9.0 

7.0 

5.0 

3.0 

1.0 

.---r---r-~.-~--~--~--~--~--~4.0 

B 

Ul l 

3.0 

2.0 

1.0 

L-~L-~--~---L---L---L--~--~~0.0 

! ; 0 L-~~~--~~JL---L---L--~--~~o.o : ;, c :' '~: J :u" : : P~: ~ 

~~--L-~o~~N~io~c-L:A_e_~L:_J~:u_T_'~--L: -l~~B?68 

B uT T 

fo.o 

j 30.0 

10.0 

13.0 

11.0 

9.0 

7.0 

5.0 

L_~~~--~---L---L---L--~--~~3.0 - - H 

: 

I : J Co 0 A B '1 JuT 1 J 1 • 0 L_ __ L_ __ L_ __ L_~~~~~--_J __ _J __ ~ 0.0 

--~.--.---.---.---.---.--,---,---, 4700.0 

..c 

1-

X 

.0 

a: 

.0 

a: 

X 

..0 

z 

(/) 

u 

4200.0 

3700.0 

3200.0 

2700.0 X 

<1l 

2200. 0 a:l 

1700.0 

1200.0 

B NED CNA 11 JJ 700.0 

L-~OL-~O~HL-~L-~--~v~--~--~--~--J200.0 

.-~~~--~--~--~--~--~--~~4700.0 

l 

u 

4200.0 

3700.0 

3200.0 

2700.0 

2200.0 

1700.0 

1200.0 

N B NED C A ~JJ 700.0 

L-~oL-~~"L-~~~--~--_J __ _J __ _J __ ~200.0 

9 8 7 6 5 4 3 2 0 9 8 7 6 5 4 3 2 0 

MgO CONTENT, IN WEIGHT PERCENT 

Figure 4. Continued. 

56 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Croup, Washington, Oregon, and Idaho 
L 9.0 

.0 7. 0 

~ 5.0 co 

.....J 3. 0 

E 

~ 11.0 

~ l.O 

20.0 ~--~--~--~--~--~--~--~--~~ 

18.0 

0 16.0 

g JLI. 0 

x 12.o 

co 10.0 m :C B. 0 

~ 6.0 

4.0 

2.0 

32.0 

30.0 

28.0 

26.0 

211.0 

A 

NED CN B 

eJ CIM 

G 

KJ 

J 

G 

T 

: : l 

22.0 .---.---.---.---,---.---.---~--.---, 

0 17.0 

0 

0 

x 

co 

m 

;;:: 

~ 

12.0 

7.0 

2.0 

.s::. s. 0 

!;; 

~ 0.0 

M 

Cl D 

N E C N 

0 A 

G 

~T : : ~ 22. 0 ,----.---.---.---.---~--..,----.----.----. 

0 17.0 

0 

~ 

~ a: 

12.0 

7.0 

2.0 

T 

u 

c 

~--~--~--.---.---.---.---.---~r-,,85.0 

0 M 

0 

C A 

fo N 

N 

KJ 

G J 

B 

75.0 

65.0 

u 55.0 

35.0 

25.0 

15.0 

L---~--L---L---L---L---~--~--~~5.0 

.---~--.---,---r--TTG---,---,---,---,33.0 

29.0 

K 

J 25.0 

A 

J 21.0 co 

m 

M 

M 

0 

C N B 

JJ 

K 

A G 

NE[JCN B 

N 

~ 

~ 17.0 

13.0 

9.0 

45.0 

40.0 

35.0 5 c) 

~ 

.s::. 

30.0 t::: 

~ 

25.0 

20.0 

L---~--L---L---L---~J~~~~--~--~~ 15.0 

.---.--,.--,---~N--.---.---.---.---. 13.0 

11.0 0 9.0 0 

7.0 

Eo c 5.0 

3.0 

L---~--L---L---L---~--~--~--~~ 1.0 

BG 

A KJ J 

X 

:0 

a: 

~ 

9 B 6 5 3 0 9 6 5 0 

MgO CONTENT, IN WEIGHT PERCENT 

Figure 4. Continued. 

Tables and Figures 57 
A I 0 0 13.0 

8 0 

I 

• 

I.~ •~~~B • 

I 11.0 

.0 6.0 9.0 

>- 4.0 7.0 - z :I: 2.0 0 

0.0 ~~B 5.0 :::J 

....1 

20.0 1£ 3.0 ~ 

E 15.0 

~ : ~:~ ~~> : l l.O a: 10.0 w (/) a.. 5.0 

:ez ·~:B : 12.0 (/) (I) 

0.0 u 1-

a: o.o 80.0 ~ 5000.0 

66.7 ~ 

t-=' 53.3 4000.0 z 

w co 40.0 1- ....1 z 

~~B 0 26.7 3000.0 u 

]Q X 1-

13.3 (Q z m w 

0.0 2000.0 ~ 

w 

....1 

600.0 w 

z ~mQ13Y- B 1000.0 

0 500.0 

::::i 2 ....1 

~ 400.0 0.0 

a: X 300.0 2.0 w N Q_ 

(/) 200.0 ~~fijtfl 1we B 1. 5 

1- 1.1) 

a: 1 2 

~ 100.0 1.0 0 N 

a.. 

~ 0.0 

-~~B 0.5 

t-=' 

100 0 l ]d? 

z 

: 1: 2 :~~§~<~:B :l 0.0 UJ 

1- X LLO z >-

70.0 

40.0 0 1-

u I 0. 0 z 

1- w 

u z 4.0 a: UJ 

I • 

~•~ ~~B • 

I 3.0 w ~ 3.0 a.. UJ ;lfM?lllb B 1- ....1 

~ :I: f 2.0 N (.9 

2.0 1.0 0 w ~ 

t ~ 0.0 ~ 

600.0 t-=' 1.0 z 500.0 w 

1-

400.0 2 

~'13~m4~6 z 

~ 0 

300.0 B 0.0 u (/) w 200.0 4.0 0 

x 100.0 0 

0.0 3.0 

80.0 ! : 

I: 2 ~~~~<~:B : l X 60.0 

.0 40.0 B a: 20.0 

,(/~~ 0 2.0 N 

0.0 ~ 

60.0 

50.0 

I : 

:2 ·~~~~<~B : I frl' " X 40.0 1.0 

.0 

z 30.0 1~ ;?0.0 

10.0 

0.0 0.0 

0 9 0 3 s 9 

THORIUM CONTENT, IN PARTS PER MILLION 

Figure 5. Chemistry of selected oxides and elements in patible oxides and elements. B, Grande Ronde Basalt, traceunits of the Yakima Basalt Subgroup, presented as thorium element ratios. C, Wanapum Basalt, minor and trace invariation diagrams. Data from tables 3-5; symbols as in compatible oxides and elements. 0, Wanapum Basalt, 

figure 4. A, Grande Ronde Basalt, minor and trace incom- trace-element ratios. E, Saddle Mountains Basalt (of Grande 

58 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
B 

~ n 1 : ~:~ ~~: B • 1 1.0 

E 4.o ~ 

j 1.0 

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18.0 

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0 17.0 

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5 6 

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2 

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8 

2 

29.0 

25.0 

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c.c 

17.0 :i2 

13.0 

9.0 

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.---.-----.---,---..,----,----,::--,--..,-----, Ill. 0 4xi£ 12.0 

I 2 

2 

l£EEE ~ ~ ~ 10.0 

~-~~8 0 B ::~ ~ 4.0 

2.0 

L------L--.I.--....l.--...._____.I _ _..J... _ __.___......._____.J 0. 0 

.---.----r--......--..,----,---,-----.---..,-------, so. 0 

2 8 

2 

4 

3 5 6 8 

llS.O 

40.0 

35.0 5 

c) 

X 

:E 30.0 

~ 

25.0 

20.0 

1

13.0 

11.0 

0 9. 0 ci 

7.0 X 

1) s.o a: 

3.0 :i2 

l.O 9 

THORIUM CONTENT, IN PARTS PER MILLION 

Ronde affinity), minor and trace incompatible oxides 

and elements. F, Saddle Mountains Basalt (of Grande 

Ronde affinity), trace-element ratios. G, Saddle Mountains Basalt (of Wanapum affinity), minor and trace incompatible oxides and elements. H, Saddle Mountains 

Basalt (of Wanapum affinity), trace-element ratios. 

Tables and Figures 59 
c ~ i'f I J I : ' B ~ F ~ : : : I 0.0 

20.0 t 15. 0 

E 10. o (fJ 

5.0 J 0.0 :1 : : B~ F>< : : l 80. 0 r-----r----.---,--..,.--..---.----.---.---, 

66. 7 

53.3 

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13.3 

J 

0.0 

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z 

0 

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(fJ 

to: 

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: J B i. F: (,\! : j 2

. 

0 

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4000.0 

3000.0 

2000.0 

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3.0 

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a: 

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8 

~ _____._____.__F ~ ::: 

0 5 8 9 0 5 8 9 

THORIUM CONTENT, IN PARTS PER MILLION 

Figure 5. Continued. 

60 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Croup, Washington, Oregon, and Idaho 

~ 

!-=" 

z 

w 

1-

z 

0 

u 

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THORIUM CONTENT, IN PARTS PER MILLION 

Figure 5. Continued. 

Tables and Figures 61 
E ~ !'f I : ; ~ : oL ~ ' 

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500.0 

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F 

: ~ ffi ' : L ~ > ~ : ~ 

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0 

~L ~ ~f ::: 

0 8 9 0 8 9 

THORIUM CONTENT, IN PARTS PER MILLION 

Figure 5. Continued. 

62 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 

~ 

..... -

z 

w 

..... 

z 

0 

(.) 

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5 6 8 

ro ll 0-

. 0 9. 0 ci 

1.0 ~ 

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1.0 9 

THORIUM CONTENT, IN PARTS PER MILLION 

Figure 5. Continued. 

Tables and Figures 63 
G ~ ~I I : ~ :~" " c 

8 

R G u~T J l 0.0 

z 

0 

::::i 

....J 

~ 

C/) 

E ~~. 10.0 ~ ~ 5.0 

0.0 : ~ :~ ~ < 8 

~ ~ ~KT >~ 8 0. 0 r----r-----.-----.----,----,--~-.,.--.....-------, 

8 66.7 

53.3 

..3 40.0 N C 

R G J 

26.7 

13.3 

0.0 

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500.0 

8 400.0 

X ffi N 300.0 

Q.. 

C/) 

1-

a: 

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z 

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z 

w 

1- X 

z >-

0 

u 

1-

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UJ 

~ 

UJ 

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UJ 

200.0 

100.0 

0.0 

100. 0~ 70.0 

40.0 

10. 0 

G K R J~ 

6 0 0. 0 r----r-----.-----.----,----,--~-.,.---.-------, 

X 

500.0 

400.0 

U5 300.0 

200.0 

100.0 

0.0 

B 

R 

G 

T 

J 

~ !U I : @ : : c : B ~ G: ~~T : J] 0. 0 L------1--"Z..---"""------"'-----'----'----'--~--'--_..J 

50.0 60.0 I X 40. o .D 30. 0 

z 20.0 

10. 0 

0.0 

: ~ :~ ~ C ' B ~ ~ ~h ' J l 

B 

& N C 

N R 

G 

K 

L 13.0 

11.0 

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7.0 

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L-~-~-~---'----'--~--'---~~ l.O 

: 

! G: ~wT JJ2.0 

L-~-~-~~--'-~--'--~--'--~~~o.o c 8 ~ . ~·· .9 

.---------.---,.--.,..----.----,--~-,.---.------, 5000. 0 

T 4000.0 

3000.0 

2000.0 

B ~ N C 

0'1 G K R J~ 

1000.0 

L-~-~-~---'------'----'-----'---...1..--~ 0. 0 

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8 1.5 

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1 1.0 0 .... 

rtf'1 N R G J ~ 0.5 

t-----l-~---l..---'-----'-·---'-----'---...1..-----' 0. 0 

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8 

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a: 

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1-

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c T ~ 

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u 

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0 8 9 0 3 5 8 9 

THORIUM CONTENT, IN PARTS PER MILLION 

Figure 5. Continued. 

64 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
H 

E 11.0 

~ 

j 1.0 J~ 

20. 0 ...------,---,----.---......----,----...----.---.------, 

18.0 

0 16.0 

g 14.0 

~ 12.0 

It! 10.0 

~ 8.0 

..... 6.0 

4.0 

2.0 

A 

N C B 

G 

K J 

. 

loiTT 

2 2. 0 .----..--,----.---......----.----.,.---,---.----, 

0 17.0 

0 

0 

x 

co 

m 

~ 

12.0 

I 7.0 

2.0 

5.0 .l: 

t 

I 0.0 

B 

~M DEN N C 

G 

K 

A J 

' 

22. 0 .----..--,-----.----r-----.---.----.---,----, 

17.0 

0 

0 

~ 12.0 

en 

:0 

a: 7. 0 

2.0 

Cl 11 

Cl 

c 

K J 

i 

B A G u 

.----..--r---.---.------r--.---,---,--'fl 85. 0 

B G 

c R 

N 

u 

K 

75.0 

65.0 

J 55.0 

45. o en 

~ 

35.0 

25.0 

15.0 

L-~---1--~-~~-~-~-~~s.o 

,....----,----,-----.----r-----.--,(]..,.--.-----r--, 3 3. 0 

K 

A 

N C B 

29.0 

J 25.0 

~ 21.0 It! 

m 

17.0 ~ 

13.0 

9.0 

1 l) lT l___J. _ ___j__.......L.__...L.___..Ji..___.J.. _ _L_~__..J s. 0 

.------,----,----.--.......-----,,---.----.---.,.------., I ~ • 0 

12.0 

10.0 

J- 8.0 a.. . ~ 1 6. 0 

R G 11.0 

@'1 [!N N C B 2.0 

L__~-=--L-~-~~-~---'--__J____..J 0. 0 

...-----..--,-----.----r------,---.-----.---.,.------., s 0. 0 

M 

(j 

N 

N C B R 

G K 

J 

1 

45.0 

40.0 

35.0 0 

0 

~ 

.l: 

30.0 1:::: 

~ 

25.0 

20.0 

L___..!. _ ___j__.......L.__...L.__i..__~---1----L--~ 15. 0 

11.0 

0 9.0 0 

1

13.0 

7.0 X 

::0 s. 0 a: 

J 3.0 ~ 

1.0 

0 9 0 6 9 

THORIUM CONTENT, IN PARTS PER MILLION 

Figure 5. Continued. 

Tables and Figures 65 
w 

1-

a: 

0 

z 

0 

I 

u 

:i2 

u 

0 

a: 

w 

....J 

0 

I 

~ 

A 

10 

El JOSEPH 

o 1A N2 

~ 1A N2* 

El 38 N2 

o LH2 N2 

• MG6 N2 

+ MG6 N2 

EJ UNC N2 

o 4A N2 

~ 4A N2 

+ 4A N2* 

La Ce Pr Nd PmSmEu Gd Tb Dy Ho Er TmYb Lu La Ce Pr NdPmSmEuGd Tb Dy Ho Er TmYb Lu La Ce Pr NdPmSmEuGd Tb Dy Ho Er TmYb Lu 

RARE-EARTH ELEMENTS 

Figure 6. Chondrite-normalized abundances of selected 

rare-earth elements (La, Ce, Sm, Eu, Tb, Yb, and Lu) in 

flows of the Yakima Basalt Subgroup. Values used in 

normalizing are those of Haskin and others (1968). 

Names of geochemical units as in tables 3-5 and figures 

4-5. See table 1 for stratigraphic association of units. 

A, Grande Ronde Basalt. Data arranged in stratigraphic 

order from youngest (1 A N2) to oldest (AS 16 R 1 ), using 

terminology of Mangan and others (1985, 1986); data 

for the Joseph volcanics unit of Kleck (1976) UOSEPH in 

upper left box) and one sample of the Imnaha Basalt 

(IMNAHA in lowermost right-hand box) shown for 

comparison. 8, Wanapum Basalt. Data shown in two 

boxes at upper left, arranged in stratigraphic order from 

youngest to oldest within members. Priest Rapids 

Member (PV, LOLO INC, ROSALIA); Powatka flow (PH 

POWAT); Roza Member (ROZA); Frenchman Springs 

Member (FS INC; FS ANOM); Eckler Mountain Member 

(SHUMAKER=PH SHUM; SW LOOK; DODGE; 

ROBIN). C, Saddle Mountains Basalt. Data arranged by 

member, from youngest to oldest, from Lower Monumental Member (LM at upper right) to Umatilla Member 

(UMATILLA at lower right). 

66 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
w 

Ia: 

0 

z 

0 

I 

u 

~ 

u 

0 

a: 

w 

....J 

0 

I 

~ 

w 

u 

z 

<( 

0 

z 

:::::> 

al 

<( 

w 

t9 

<( 

a: 

w 

~ 

0 

w 

N 

::::i 

<( 

~ 

a: 

0 

z 

1 

1000 

100 

10 

1 

1000 

100 

10 

El 5F N1 

El AS16 N1 

• AS16 N1 

+ AS16 N1 

X AS16 N1 

., SH N1 

+ AS16 N1 

" UNC N1 

N AS16 N1 

>- AS16 N1 

La Ce Pr NdPmSmEuGd Tb Dy Ho Er TmYb Lu 

Figure 6. Continued. 

El AS16 N1 

€l AS16 N1 

• AS16 N1 

+ AS16 N1 

• 3G N1 

<> 3G N1 

+ 5F N1 

LaCe Pr NdPmSmEuGd Tb Dy Ho Er TmYb Lu LaCe Pr NdPmSmEu Gd Tb Dy Ho Er TmYb Lu 

RARE-EARTH ELEMENTS 

Tables and Figures 67 
w 

1--

a: 

0 

z 

0 

:J: 

u 

:2 

u 

0 

a: 

w 

...J 

0 

:J: 

~ 

w 

u 

z 

~ z 

::::> 

CD 

<( 

w 

l? 

<( 

a: 

w 

~ 

0 

w 

N 

:::i 

<( 

~ 

a: 

0 

z 

10 

EJ ASOTIN 

o VC ASOT 

• SW HUNTZ + HUNTZ 

X EAGLE 

~ VC LAP 

+ WILBUR 

c 

LaCe Pr NdPmSmEuGdTb DyHo Er TmYb Lu LaCe Pr NdPmSmEuGdTb DyHo Er TmYb Lu LaCe Pr NdPmSmEu Gd Tb DyHo Er TmYb Lu 

RARE-EARTH ELEMENTS 

Figure 6. Continued. 

68 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Croup, Washington, Oregon, and Idaho 
A B c l!: 0 ~,------,--,-

'~ f--,-; ·~-~ 

C~ j 16. c 

t 

'20~ -1 

0 

1 

t -l ~ 12. c 00 

t ~ ~ j j e. o SL ~ E C 

' 12 X~~ 3 1 [ 12 11~ -1 lJ 3 ~ j' ., 

~. 0 j ~ 0 

~ l. 0 

~ ~ '!I. 0 

~ j -1 

..c 40.0 3 J 

a.. l t· 40. 0 

~ :0 3 3 TT a.. 

00 j p 

~ 39.0 

2 ~~BE -l L 39. 0 

2 ~f"' ~ Q SL 

4 3 

~ 38. 0 38' 0 

..c 

:::: r·~eE a.. '3' ' 

: : : 

• 

>1 t 12:~~ '3 ' 

' : ' 

. :J [ : 12: 

: : 

i ~ s'' 

' 

: 

:J" j"" <: 

0 

~ 

..c 

t I 5. 0 

20.0 ro J 

I 9. 0 2 2 2 a; 

1 ~ E 3 I r~ 3 4: ~ 19. 0 

..c B 

a.. H I , 0 

<: 

~ 18.0 p n 

:0 ., 

a.. j G s 

~ j 

]7. 0 

~ I 7. 0 

j 

]6. 0 ~ 16.0 

6.0 e. o I I l 

2 X 2 2 

Cs ¥ Cj., -2.0 ~ -2. 0 

3 3 l 1:) J J z -12.0 -I 2. 0 w Q 

s 

. 22.0 -22. 0 

4 

-32.0 -32.0 

0. 702 0' 709 0. 716 0. 702 0' 709 0. 7 I 6 0. 7(,2 0. 709 0. 7 I 6 

B7Sr/sssr 

Figure 7. Isotope data for units of the Yakima Basalt Subgroup. Symbols 1, 2, 3, and 4 represent Carlson's (1984a, table 

3) end-member compositions Cl, C2, C3, and C4. See text for further discussion. A, Grande Ronde Basalt. *, LH2 N2 

geochemical unit; #, MG6 N2 geochemical unit; other symbols as in table 3. 8, Wanapum Basalt. Symbols as in table 

4. C, Saddle Mountains Basalt. Symbols as in table 5. 

Tables and Figures 69 
0 

i= 

s. 0 

y. 0 

3. 0 

;>. 0 

I. 0 

0. 0 

A 

I ;>. 0 r-----.r------..--.---.----,..----.---, 

1-

z 

w 

u 

a: 

w 

a.. 

1-

:::c 

~ w 

~ 

~ 

.._.: 

z 

w 

1-

z 

II. 0 

10.0 

0 

10 9. 0 u 

B. 0 

7. 0 

6. 0 

16.0 

17.0 

16.0 

15.0 

0 0 U ~ JILO 

w 

0 

x 

0 

13.0 

12.0 

11.0 

10.0 

9. 0 

' 

2 

2 c 0 

R 

c 

0 

R B 

E 

E B 

B 

E 

I 7. 0 r-----,--,--,---,---,--..------, 

16.0 

I 5.0 

~ 14.0 

<( 13.0 

12.0 

11.0 

I~ 

Co 

E B 

I 0. 0 ~---''--------'--~----'--~---'-~ 

9 6 

8 

J J 

J 

J 

J 

J 

6 

B C 

C E 

B E 

c 

B 

C E 

B 

E 

c 

CJ H 

E C 

E 0 

0 c 

B Be 

G 

Q 

Q 

H CJ R 

4.0 

3. 0 

A 

2.0 

1.0 

~~~~-~--~--~-~~o.o 

,..------,--.--.----.----.-.---. 12.0 

II. 0 

10.0 

9.0 

6. 0 

R 

7.0 

L-~~~-~-~-~-~~s.o 

r-----.r------r--.----.----.-.---. 19.0 

8 16.0 

17.0 

c 

0 G 16.0 

G 15.0 

0 c JILO 

13.0 

Q R 

H 0 12.0 

A 11.0 

H Q 

10.0 

0 

L-~~~-~---L--L-~~9.0 

,..------,--.--.----.----.-.---.17.0 

0 Q 16.0 

H IS. 0 

]14. 0 

R 

13.0 

12.0 

11.0 

~~-~-~-~-~-~~10.0 

5 

MgO CONTENT. IN WEIGHT PERCENT 

Figure 8. MgO variation diagrams comparing major-oxide 

chemistry of representative rocks and coexisting glasses in 

units of the Yakima Basalt Subgroup. Glass analyses adjusted before plotting (see text). Plots of CaO-MgO and 

AI 20 3 -Mg0 are annotated to show average trends of bulkrock chemistry (heavy solid lines) and representative trends 

connecting coexisting rock and glass (short solid lines, arrows point toward glass composition). A, Grande Ronde 

Basalt. Symbols as in table 3. B, Wanapum Basalt. Symbols 

as in table 4. C, Saddle Mountains Basalt. Symbols as in 

table 5, except 0, SW NEW only; Q, HUNTZ only; R, VC 

LAP only. 

70 Chemical Data, Yakima Basalt Subgroup, Columbia River Basalt Group, Washington, Oregon, and Idaho 
1000 

EJ WT NEPH EJ VC GRNGE - E) WT ANDES E) PH EDEN 

-= WT JONES ~ WT OBHTI 

w + WTSUGMT + WT OBLTI u 

z X WT SPRMT X vc CRAIG 

<( ~ WTWBRMT ~ VC SWAMP 

0 w + VC IFLAT z t: ~ VC POT ::) a: 100 

co 0 

<( z w 0 

(.9 I 

<( u 

a: ~ w u ~ 0 

a: 

0 w w .....J 

~ 0 .....J 10 I <( 

~ ~ 

a: 

0 

z 

LaCe Pr NdPmSmEu Gd Tb Dy Ho Er TmYb Lu La Ce Pr Nd PmSmEu Gd Tb Dy Ho Er Tm YbLu 

RARE-EARTH ELEMENTS 

Figure 9. Patterns of chondrite-normalized abundances of rare-earth elements in additional analyzed flows. 

Symbols for flows as in tables 14 and 15. 

Tables and Figures 71 
GPO 685-041 /9779 
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