The Behavior of Molybdenum., Tungsten, and Titanium

The behavior of molybdenum, tungsten, and titanium in the porphyry copper environment

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Authors Kuck, Peter Hinckley

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Link to Item http://hdl.handle.net/10150/565421 THE BEHAVIOR OF MOLYBDENUM., TUNGSTEN, AND TITANIUM

IN THE PORPHYRY COPPER ENVIRONMENT

Peter' 'Hinckley Kuck

A Dissertation Submitted to the Faculty of the

DEPARTMENT OF GEOSCIENCES.

In Partial.Fulfillment of the Requirements. ' ■ For the Degree of

DOCTOR OF PHILOSOPHY

In the Graduate College ■

THE UNIVERSITY OF ARIZONA

1 9 7 8 THE UNIVERSITY OF ARIZONA

GRADUATE COLLEGE

I hereby recommend that this dissertation prepared under my Peter Hinckley Kuck direction by ______, , The Behavior of Molybdenum, Tungsten, and Titanium entitled ______in the Porphyry Copper Environment be accepted as fulfilling the dissertation requirement for the Doctor of Philosophy degree of ______

Dissertation Director Date

As members of the Final Examination Committee, we certify that we have read this dissertation and agree that it may be presented for final defense.

\ R A j r i A hi / 7IT

2 / 1 r

7 -

Final approval and acceptance of this dissertation is contingent on the candidate's adequate performance and defense thereof at the final oral examination. STATEMENT BY AUTHOR

This dissertation has been submitted in partial fulfillment of requirements for an advanced degree at The University of Arizona and is deposited in the University Library to be made available to borrowers under rules of. the .Library.

Brief quotations from this dissertation are allow able without special permission, provided that accurate ■ acknowledgment of source is made; Requests- for permission for extended quotation from or reproduction of this manu script in whole or in part may be granted by the head of the major department or the■Dean of the Graduate College when in his judgment the proposed: use of the material is in the interests of scholarship. . In all Other instances, however,. permission must be obtained frOm the author. ACKNOWLEDGMENTS

I am deeply indebted to Dr. Paul E. Damon for his

supervision and support of this dissertation. Drs. John

W. Anthony, John M. Guilbert, and John S. Sumner provided

many helpful suggestions, comments, and constructive

criticisms. I would.like to especially thank Dr. George

W. Nelson fo r _his encouragement 'an d .invaluable.assistance . ■ •

in many aspects of the project. Dr. Nelson, Dr. .Morton E . -.

Hacks, and other members of the Nuclear Engineering;Depart- .

ment irradiated more than one hundred mineral samples in the

TRIGA reactor and allowed me to.use their gamma-ray .

spectrometry system.

It is a pleasure to express my appreciation to

Robert B. Scarborough who assisted me in both the laboratory

and the field. Dr. Muhammad Shafiqullah, Daniel J. Lynch,

and the other members of the Laboratory of Isotope Geo-

.chemistry kindly provided potassium^argon data on several

mineralized intrusives. Dr. Denis L. Norton and Jerry E.

Knight gave useful suggestions and assistance in con

structing activity diagrams. Dr* Donald .Ev Livingston .

provided constructive advice on x-ray fluorescence. Thomas

M. Teska and Horton E. Newsom helped with the electron

microprobe analyses. iv

Michael H. Rauschkolb and his associates.-at AMAX

Arizona, Inc. collaborated with me on the .examination of the copper-molybdenum-tungsten mineralization in the Twin

Buttes ore body. Calvert D. lies of the Duval Sierrita

Corporation provided samples and data on the mineralization at the Esperanza and Sierrita open pit mines.

I would also like to thank the following individuals for their help: Janis K. Blainer, the late Thomas Breen,

Dr. Donald M. Burt, J. L. Christman, .Richard. Graeme, Dr.

Frederick T. , Graybeal , James Guthrie, Dr ^ Herbert E.- Hawke.s,

Margo -Jennison, Peter L. Kresan, Norman E . Lehman, Richard

Moore, Dr. Henn Oona, Dr. Eberhardt A. Schmidt, and Dr.

Anne M. S'igleo. I owe a special debt of thanks to Dr.

David L. Perry fdr: introducing me to the problems of molyb denite deposition. Mr. Henry G. Worsley, the owner of the

Mary G mine, provided information on the mining history of the Las G.uij as and San Luis Mountains. The following mining companies - gave mb permission to. collect samples from their properties or provided samples for this study: ANAMAX .

Mining Co., Cyprus Bagdad Copper Corp., Duval Sierrita

Corp., Oracle Ridge Mining Partners, the Ray Mines Division of the Kehnecott Copper Corp., and the Phelps Dodge Corp.

- .The editorial suggestions of Kathleen Roe Trevena were of great value and helped to make parts of the dis sertation smoother and clearer. Finally, I would like to ■thank Professor ter ah L„ Smiley, for his. valuable counsel

and timely advice.

Financial assistance was furnished in part by the

National Science Foundation through a.summer traineeship

and under Grant EAR?6-02590 to Paul E. Damon. TABLE OF CONTENTS

Page

LIST OF TABLES ...... ix ■

LIST OF ILLUSTRATIONS V ...... xii

ABSTRACT ' ...... « ...... xvi

■THE; MOLYBDENUM-TUNGSTEN' PROBLEM ;...... 1

1.1 Differences in Behavior between Molyb denum and Tungsten • in Porphyry Copper Deposits ...... , ...... 1 1.2 Economic Implications of the Molybdenum- .. Tungsten- Problem . . . . . :...... 5 1.3 Possible Explanations of the Difference in Behavior between Molybdenum and. Tungsten ...... 8

GEOCHEMISTRY OF MOLYBDENUM, TUNGSTEN, AND. TITANIUM ...... 15

2.1. Differences in Electronic Structure . . . 15. 2.2 Effect of Differences in Nuclear Struc ture on the Abundances of the Three .. ■ Elements ...... ■.■. . ..- . *■ ...... 2 4 2 . 3 Molybdenum and Tungsten Minerals' .'., . . .. 30 2.4 Laboratory Synthesis of Molybdates . and Tungstates ...... > . . .40

MOLYBDENUM, TUNGSTEN, AND TITANIUM MINERALIZATION IN SOUTHERN ARIZONA ...... 49

3.1 Area of Investigation ...... 49 3.2 Age Relationships ...... 52 3.3 Types of Deposits ...... 53 . 3.4 The Spatial Distribution of Molybdenite and Scheelite in Porphyry Copper Deposits and Related Skarns . . ■. . . , . .. . , . , . 57 3.5 . Rutile and Other Titanium-Bearing Minerals Associated with Chalcopyrite- Molybdenite Ores ...... 68 vii . TABLE OF CONTENTS (Continued)

Page

CHEMICAL ANALYSES OF ORE MINERALS „ . . . . . 80

4.1 Preparation of Standards and .Samples . . . 80 4.2 Emission Spectrographic Analyses ...... 85 4.3 X-ray Fluorescence Analyses ...... 86 4.4 Neutron Activation Analyses ...... 87

DISCUSSION OF CHEMICAL ANALYSES ...... 95

5.1 Minot Elements in Molybdenite . . . . .' . 95 5.2 Rlienium,' Selenium, and Other Trace ' Elements- ' in Molybdeni te " . . . I . . . . . 98 : 5.3 Minor Elements in Wolframite ...... 114. ' ; 5.4 Scandium, Niobium, and Other Trace Elements in Wolframite ...... - . . 115 l 5.5 Minor and Trace Elements in Scheelite . 12 0 5.6 Tungsten> Copper, and Other Trace Elements in Rutile ...... ' 127

TRANSPORT AND DEPOSITION OF MOLYBDENUM AND Tungsten , , ...... , . 130 ■

6.1 Transport Problems . . . a . .. . . »•. . . 130 6.2 The Solubility of Different Molybdenum and Tungsten Minerals in Hydrothermal

Bf ine s ■' o . a . ;. . e .- . * ■ e ‘ a . o . 0.0 e « « . « 132 . . 6.3 Depositional Temperatures ...... 133 ; - 6.4 . Stable. Mineral Assemblages ...... 143 6.5 Activity-Activity Diagrams for the Ca—Fe—Cu—Mo—W—S—0—H System ...... 145

CONCLUSIONS \ ...... 163

APPENDIX A: COMPILATION OF 40K/4°Ar AGE DETERMINA TIONS OF LARAMIDE INTRUSIVES IN . SOUTHEASTERN ARIZONA THAT ARE ASSOCI ATED WITH COPPER-MOLYBDENUM OR COPPER- ' ■ ' TUNGSTEN MINERALIZATION: : . . 1 ...... 167 •

APPENDIX B: COMPILATION OF 40K/4°Ar AGE DETERMINAr- .. TIONS OF OLIGOCENE AND MIOCENE IN TRUSIVES IN SOUTHEASTERN ARIZONA . . . 176

APPENDIX C;' SEMIQUANTITATIVE EMISSION SPECTRO GRAPHIC ANALYSES OF MOLYBDENITE . . . 181 viii

TABLE OF CONTENTS (Continued)

Page

APPENDIX D : EMISSION.SPECTROGRAPHIC ANALYSES OF . FERBERITE, WOLFRAMITE, AND HUEBNER- ITE ...... ' > ...... 213

APPENDIX E : ' EMISSION SPECTROGRAPHIC ANALYSES OF SCHEELITE AND POWELLITE . 233

APPENDIX F : EMISSION SPECTROGRAPHIC ANALYSES OF : RUTILE, MAGNETITE, AND HEMATITE . ... 242

APPENDIX G :. CONVENTIONAL X-RAY FLUORESCENCE ANALYSES OF FERBERITE, . WOLFRAMITE, "■ AND HUEBNERITE ■ <, . „ ...... 2 51

APPENDIX.H : THERMODYNAMIC. PROPERTIES OF SELECTED MOLYBDENUM AND TUNGSTEN COMPOUNDS, , INCLUDING THE : DATA FOR THE MOLYBDATE. AND TUNG STATE ANIONS ...... 256

REFERENCES. CITED ...... o; ;...... 26.0 LIST OF TABLES

Table Page

1. Atomic properties of titanium, molybdenum, an cl ■ tungsten ». e & * « ». « # » -» o » » » » a » « 2

2. Molybdenum-tungsten isomorphism in por phyry copper deposits „ « i ° .• « - . .. . • 3

3. Values of the Gibbs free-energy of formation for selected molybdenum and tungsten com^ pounds ».o...... 9

4. Electronic configurations of. the neutral

Cl L- OXi-L £5 e O • e a a a a a -a a a a a a . ■ a a a a a a 1 2

5. Deviations In atdmic orbital filling . 18 .

6. Various covalent, ionic,.and.metallic radii for titanium, molybdenum, and: tungsten. ^ . . . . . 22

7» The partial ionic character of different - • bonds formed by titanium, molybdenum, and tungsten a a a a a a a , a O' a a . a a a . a a - a -a ■ a a 2 3

8 a The concentration of molybdenum and tungsten in different phases • of meteorites . . . 26

9. Titanium, copper, molybdenum, and tungsten in U.S. Geological Survey Standard Whole Rocks a . O a a a a a a a a a . .. a a a a a • a a 27

1 0 a Isotopic properties of titanium, molybdenum, and tungsten ...... « ...... 29

11. Comparison of the cell parameters of molyb- . .denite , tungstehite, and related structures . ... 31

12. Optimal pH values for the precipitation of .. selected transition metal normal molybdate S a a a a a." a a a a a a a . a a a a a a a a a 4 3

13. Known and predicted molybdates and tung- , states formed by the divalent metals ...... 46

ix X

LIST OF TABLES (Continued)

Table Page

14. Mining districts in southern Arizona with known porphyry’copper-molybdenum mineraliza- L ZL IX 4 e ■ ... e © # . . * 4 4 4 4 e 4 4 4 4 - 4 4 4 '4 5 3-

15.. Selected tungsten occurrences in south eastern Arizona ...... 59

16 4 Mill grade assays of sulfur and various transition metals in four rock types at the ANA%AX Twin Buttes mine, Sahuarita, Pima County, Arizona . « «, ...... 71

; 17. " Estimated distribution of titanium in the Ruby Star Granodiorite of the Pima mining >■

^1-L. S "t 3^-1 ‘G 4 4 * 4 4 4 . 4 4 4 4 * 4 .0 *4 e 4 . . . . * 7 3

18. Unit cell parameters for rutile from .chalcopyfite-molybdenite deposits in the Patagonia Mountains > Santa Cruz County g *. *A.n z ona . &. . .* . *...... * . 7 6

19. Cell parameters for tungsten-rich rutile (PHK-12-72), Esperanza pit, Sahuarita, ■ Pima County, Arizona 0 ...... 78

20. , Semiquantitative spectrographic analyses of MBS SRM-333, molybdenite concentrate, dated 14 March 1973 ...... *... 81

21. '■ Semiguantitative spectrographic analysis . of NBS: SRM-I54a, titanium dioxide - . *...... 82

22o . X-ray fluorescence techniques used in the analysis of wolframite and scheelite ; . . . . . 88

23. Summary of emission spectrographic data for 31 molybdenites ...... ’. 96

24. Selenium and other trace elements in molybdenite . . . . . ,...... 100

25. Thermal neutron activation analyses of . molybdenites . , ...... 105

26. Summary of emission spectrographic data for 22 wolframites ...... 116 xi

U S T OF TABLES (Continued)

Table Page

27. Wet chemical and spectroscopic analyses of wolframites from the Erzgebirge and neigh- . boring mining districts in Saxony and

• 'BOtietir U ‘ . o . . o 9 9 - 9 e . 9 a 9 a a a. a < . 117

289 Summary.of emission spectrographic data for eight scheelites . . . . , . , . » . . . . a 122

29. Electron microprobe analyses of molybdian

scheelite from Twin Buttes . . « . , . . . . . a 123

" 30» Scandium content of wolframites and scheelites . . , .•» , . . , ...... a 125

31, Summary of emission spectrographic data - for five rutiles « » » « « . « . . . » ...... a 128

32. Solubilities of the normal molybdates in water at selected temperatures „ ...... a 134

33o Solubility of' CaMoO^ in NaCl solutions of various concentrations . , ...... a 136

34. A crude solubility chart in the temperature range from 298 to 371 K for molybdenite " and selected tungsten compounds ...... a 137

35, A genetic classification of■tungsten deposits . based on the assumption that the mineral , assemblage is indicative of the temperature of deposition a -, . , , , . , . . . . . a 138

36. Dissolution reactions to bare ions for the system: Fe-Cu-Mo-W-S-O-H . . « . = . . . . . a 146

37, Equilibrium constants for the oxidation- reduction and hydrolysis of Ca-Fe-Cu-Mo-W-S- O-H minerals in aqueous solution at elevated temperatures, . . . , 9 ...... a 148 LIST OF ILLUSTRATIONS

Figure Page

1. Molybdenum production in Arizona, 1955 to 1 9 7 5 „ o e o e ‘ ' o e o o . o » e e ^ » o e e e « a 7

2. The buildup of isopoly molybdate and tungstate anions from octahedra of oxygen y atoms. e e o o: A a a a a a a a a a a a a a a a " 13

3« Energy levels of the intermediate n atomic orbitals as functions of atomic number . . . . 16

4„ Electronic density plots for elements in the fourth, ■fit thy and sixth, periods v ...... 20

5. Some occurrences of secondary molybdenum and . tungsten mineralization in southern Arizona • 36

6» .. Index map of. porphyry'copper deposits and related skarns in southern Arizona, as : listed in Table 14 a-.. „ , ...... 50

'7.'..Histogram of K-Ar.dates for copper-molybdenum- tuhgsten mineralization in southeastern . i zona . . . . . a ...... a ...... 54

8. Some occurrences of tungsten mineralization . in southeastern: Arizona- . ,. . ■ ■ ...... 58

9. Alteration zoning and associated mineraliza tion in the center of the San Manuel/Kalamazoo porphyry copper deposit ...... • . . . . . 64

10. Normalized mole fractions of copper, molyb- . d enum , and tungsten in altered Paleozoic .limestones, from the ANAMAX Twin Buttes mine, Pima County, Arizona . » ...... 69

11. Normalized mole fractions of iron, copper,' and zinc in altered.Paleozoic limestones . from the ANAMAX. Twin Buttes mine, Pima County, Ar i z o n a . ■ a ■ a . > ...... a ...... 70

xii xiii

LIST OF ILLUSTRATIONS (Continued)

Figure Page

12. .X-ray fluorescence calibration curve used to determine the manganese content of wolframites ...... » . . . . . , . . 89

13. The efficiency curve for the Nuclear Diodes LGCC lithium-drifted germanium detector L-982 » . . . » » ...... 92

14. Block diagram of the gamma-ray spectrometry system in the Department of.Nuclear Engineering, University of Arizona ...... 93

15. Gamma-ray spectrum of molybdenite (PHK-l2c-72) from the New Year1s Eve breccia pipe, 3760 ft bench, Esperanza pit, Sahuarita, Pima County, 12 n 3. .- o o' . o ... . . -» » . - e » « a e e e - . 1 0 9

16. Gammar-ray - spectrum revealing the - presence of trace tungsten in molybdenite (PHK-12c-72) from the Esperanza pit, Sahuarita, Pima County, Arizona ...... 110

17.‘ Gamma-ray spectrum of molybdenite .(PHK-23-69) from the El Tiro pit. Silver Bell mine, Pima County, Arizona ...... 112

18. A portion of the gamma-ray spectrum for ; ■ \. irradiated ferberite (PHK-2^69) from the San Manuel mine, Pinal. County, Arizona ....'». . . . 124

19. Gamma-ray spectrum of rutile (PHK-4-69) from the - Santo Nino mine on Mt. Washington, Patagonia Mountains, Santa Cruz County, A n z on a ...... * .. 129

20. The entropy of a cation in water as a function of the charge to radius ratio . . . . . 150

21. Theoretical activity diagram for the system: Cu« STFeS—H„ Sr H S O .. **HC1—H 0 at T atmosphere » ■ Temperature - 573 K. Log a '•«= -2.5, a (H A O ) ' 1.0 . o . . . ' . .. o .. - o e. o o a • » ' « - • . .151 2 ' . ■ - .■ - . xiv

LIST OF ILLUSTRATIONS (Continued)

Figure Rage

22. Theoretical activity diagram for the .system: Cu2S-FeS-H2S-H2S04“HCl-H20. at 1 atmosphere. Temperature = 573 K. Log a(HpS) = -4.O., a (h 2o ) =l..o ...... 152

23. Theoretical activity diagram for the systems CU2S-FeS-H2S-H2S04-H2Mo04-HCl-H20 at 1 atmosphere.- Temperature = 573 K. Log a(H2S) = -2.5, log a(Cu+)/a(H+) = -5.0, a(H20) = 1.0 ...... 155

24. .Theoretical activity diagram for the system: - - CU2S-FeS-H2'S-H2S04->i2Mo04-HCl-H20 at 1 atmosphere. - Temperature = 573 K. Log a(H2S) = -2.5 , log a (CU+ )/a (H+) = -4.0, , a (H20, = 1.0 . ' ; 156

25. Theoretical activity diagram for the system: Cu2S-FeS-H2S-H2S04-H2W 04-HCl-H20 at 1 atmosphere. Temperature =573 K. Log a(H2S) = -2.5, log a(Cu+)/a(H+ ) = -5.0, a ( H20 ) * = • T o 0 . ' o - o o - o . O O o ...... e ■ e 157

26 . Theoretical, activity- diagram for the-system: Cu2S-FeS-H2S-H2S04s-H2W04 -HCl-H20 at 1 atmosphere„ Temperature = 573 K . ' Log a(H2S) = -2.5, log a(Cu+)/a(H+) = -4.0, . 158 : :a:iH20> = 1 ':v ' ' ' 7 " 27. Theoretical activity diagram for the system: : Gu2SHR’eS-H2StH2 S04-H2MoQ4-H2W04-HCl-H20 at 1 atmosphere. Temperature ='573 K. Log a(B2S) - -2.5,'logla(Fe++)/a2^H+y = +3.0, . log a(Cu+)/a(H ) = -5.0, a(HgO) = 1.0 . . . . 159

28. Theoretical activity diagram for the system: Cu2S^FeS-H2S-H2S04-H2Mo04-H2W04-HCl-H2P ^ at 1 atmosphere. Temperature = 573 K. Log a(H2S) = -2.5, Tog a(Fe+ + )/a2 (H+ ) : = +2.5,:. log a (Cut)/a (H+ ) = -5. 0 ,• a (H20) = 1.0 v . . 160 xy

LIST OF ILLUSTRATIONS (Continued)

Figure Page

29. Theoretical activity diagram for the system: Cu2S-FeS-R2S-H2S04-H2Mo04-H2W04-HCi-H20 at .1 atmosphere. 'Temperature =-573 K. Log a(H2S) = -2.5, log a(Fe++)/aZ (H+) = +3.0, log a(Cu )/a(H ) = -4.0, a(H^O) = 1.0 . . . . . 161 ABSTRACT

Although molybdenum and tungsten (wolfram) have very

similar atomic properties, they behave differently during

the formation of porphyry copper deposits. Molybdenum is

more chalcophile and less siderophile than tungsten. This

difference in behavior is not fully understood. However,

it does suggest.that atomic orbital cross-over effects.are.

as important as dif f erences- in ionic ,radius,' ionic charge, -;V

.and.electronegativity.in explaining the partitioning of .

transition metals in nature.

A^detailed study of relatively molybdenite-rich .

ores found in the porphyry copper deposits of Arizona and.

Sonora was initiated in order to obtain quantitative informa- \ •

tipn on the molybdenum-tungsten problem. The copper-

molybdenum mineralization is genetically related to a

northwest-southeast trending belt of stocks of intermediate

composition that crystallized within the period 78 to 54 m.y.

agOi Several small tungsten deposits were formed during the

last stages of intrusive activity. A second pulse of

magmatism and copper-tungsten mineralization was super

imposed upon the belt within the period 35 to 18 m.y. ago.

Various hypogene minerals containing molybdenum -

and tungsten were analyzed by neutron activation, emission

xvi . - - . • xvii spectrography, x-ray fluorescence, and other techniques.

The molybdenites of the belt have an abnormally high

concentration of rhenium compared to samples from other parts of the world. Values up to 2000 ppm rhenium are

common in molybdenites from potassic alteration zones.

These same molybdenites contain less than 1000 ppm tungsten.

Additional information on the behavior of tungsten was •

gained from trace element studies of its two neighbors,. '

rhenium and tantalum. : The tungsten in potassic zones be-

haved more like tantalum than rhenium and substituted for

titanium in hydrothermal rutile.

Tungsten!te is not found in porphyry copper de posits . When tungsten is present, in any significant amount,'

it forms wolframite, scheelite, or occasionally powellite,

instead of the sulfide. . The scheelites from these deposits

contain'considerably more molybdenum and strontium than do ;;

oogenetic wolframites. The wolframites, on the other hand,

contain more scandium and niobium than do the scheelites.

Titanium and the rare earths are present.in both minerals.

The divalent cation (Ca*^, Mn+^ , or Fe+^) joining the tung-

state octahedfa helps determine which trace elements will

substitute for tungsten.

Activity diagrams were constructed for the Fe-Cu-

Mo-W-S-Q-H, system; at 573 K and -1. atmosphere (0> 1, MPa) . ; The :.. -2 5 aqueous H^S activity was set equal to 10 so that the X V I 11 system would represent the hypogene ore zone of a porphyry copper deposit, and allow the coexistence of chalcopyrite, pyrite, and magnetite. The data from these diagrams can be used to set limits on the MoO^- and W0^*~ activities of the ore-bearing solutions.

The differences in behavior between molybdenum and tungsten can be explained by the differences in the enthalpy ' of formation of MoS^ and.WS^, as well as of MeMoO^ and MeWO^ *i* 2 2 (Me = Ca , Mn , or Fe ). These enthalpy differences , are ^ apparently the result of d-s orbital cross-over effects, the penetration ^ of inner orbitals by outer s electrons, and half-filled subshell stabilization. CHAPTER 1

THE MOLYBDENUM-TUNGSTEN PROBLEM

1.1 Differences in Behavior between Molybdenum and Tungsten in Porphyry Copper Deposits

The atomic properties of tungsten (wolfram) are

very similar to those of molybdenum (Table 1). One might :

then•think that tungsten would fo11ow molybdenum, just as

rubidium, follows potassium> and that tungsten would be sig-''

nificantly concentrated in the sulfides of porphyry copper

deposits» ; However,, a different phenomenon, which is poorly

understood,: is actually observed. Tungsten is more sidero-

phile and less chalcophile than molybdenum. As- a result,

tungsten behaVes like tantalum and follows titanium instead

of molybdenum.

This difference in behavior is revealed - by the

mineralogy of the hypogene'ore zones. Isomorphism (Table 2)

and solid solution do not necessarily imply codeposition.

In the porphyry copper environment, the deposition of molyb-

.denite (MoS^), ferberite (FeWO^), and huebnerite (MnWO^) is

strongly favored over that of ferromolybdate (FeMoO^), man-

ganpmolybdate (MnMoO^>:, and ttingstenite (WS^) « Molybdenite

is by far the most abundant primary mineral of molybdenum

in the ores, and is. generally associated with either

: ' . ■■■ - ' iV - ^ ■ ■ ■■ 2

Table 1. Atomic properties of titanium, molybdenum, and tungsten. ,

Ti Mo W

Electronegativities

Relative, compactness scale 1.40 1.62 1.39 (Sanderson, 1971)

Conventional scale 1.5 1.8 1.7 (Pauling, 1960)

Crystal Ionic Radii (nm)

+4 Oxidation state 0.068 . 0.070 v 0.070 +6 0.062 0.062

Ionization Potentials (eV)

(Moore,:1970, and Barabanov, 1971)

. % : 6. 82 ■ 7.099 7.98 II ' 13.58 16.15 . 17.7 III. 27,491 27.16 : • 24.08 IV 43.266 : .46.4 35.36 . ' V 99.22 61.2 (48) VI 119.36 68. (61) VII 140.8 126.8 p VIII 172. 153. ? 3

Table 2. Molybdenum-■tungsten isomorphism in porphyry copper deposits.

Rare or Space Common Unknown System Group 2*

MoS 2 WS2 Hexagonal P63/mmc 2

FeW04 FeMo04 Monoclinic P.2/a 2

MnWO^ : MnMo04. Monoclinic P2/a 2

CaW04 . CaMo04 Tetragonal :'- I41/a 4:

*2 is the number of gram formula weights per unit cell.; / chalcopyrite or pyrite. Tungsten!te is much rarer than molybdenite and, even allowing- for their identical appearance has not been found, in porphyry copper deposits.:. Ferromolyb- date and mangano-molybdate have never been observed in nature, although, the two can be readily synthesized in the laboratory and are stable at 29 8 K and 1 atmosphere (0.1

MPa). • Powellite (Ca[Mo,W]0^) is much rarer than scheelite

(CaWO^) in the hypogene ores. In fact, .lass t h a n .10% of the powellite present in the Arizona copper deposits is primary;

(this study). The ferrimolybdite (Fe^Mo^O^^° 0), wulfenite

(PbMoO^), and remaining 90% of the powellite are all.secon dary alteration products of molybdenite.

As much as 3 weight percent tungsten can substitute for titanium in hydrothermal rutile. No inclusions of wol framite or scheelite were found in a rutile crystal con taining 0.8 weight percent tungsten when it was scanned with the electron microprobe. Although this variety of rutile is often associated with molybdenite, it generally contains less than 500 ppm of molybdenum. It appears that titanium is more readily replaced by tungsten than molybdenum. Experi mental data published by Kerr and Trotman-Dickenson (1976) on the strengths of the three oxide bonds show that the . molybdenum-oxygen bond is the weakest of the three: Bond strength, ^29 8 °1110^

Ti-0 677 ± 1 9 Mo-0 481 ±50 - W-0 653 ±25

In order to Obtain quantitative information on the molybdenum-tungsten problem, the author began a detailed study of molybdenite-rich ores from the porphyry copper deposits of Arizona and northeastern Sonora„ . Numerous • articles and books have been written:about this 78 to 54 m.y. old belt of copper deposits that stretches across the

Basin and Range Province from Mineral Park southeast to .

Nacozari (Damon■and MaUger, 1966; Titley and Hicks, 1966; :

Anderson, 1968; Livingston, Mauger, and Damon, 1968; Lowell and Guilbert, 1970; Lowell, 1974) = The tungsten depo&its- v at Texas Canyon, Carr CanyOn, and several other localities were formed during the last stages of intrusive activity. A second pulse of magmatism and copper-tungsten mineralization was superimposed upon the belt during the Oligocene and

Miocene. Differences between.molybdenum and tungsten are also, observed in the mid-Tertiary ores.

■ 1» 2 Economic Implications of the Molybdenum-Tungsten Problem -

The demand for molybdenum has increased markedly ; during.the last 50 years because of the exponential increase in world population, the accompanying surge in industrial -> activity, and metallurgical research advances. In 1906, world consumption of molybdenum.concentrate was less than

450 Mg (metric tons contained Mo, 95% MoS^). In recent years, molybdenum consumption has increased from 66,200 Mg in 1970 to 82,500 Mg in 1976 (Goth, 1977). Molybdenite is seldom being discarded on the dumps of Arizona's mines and is presently being recovered at a level of approximately

0.02 weight percent from the .copper ores„ : About 16 grams of molybdenum are being recovered for every kilogram of copper.

The production figures for the state of Arizona from 1955 to

1975 are shown in Figure 1„

In contrast, tungsten production in Arizona has been erratic because of price fluctuations„ Annual output reached 159.8 Mg of WOg in 1936, but was only 0.918 Mg in ■ •

1956. Since 1956, production in the state has been negli- ., gible (Arizona Dept, of Mineral Resources, 1976) . However, unpublished information indicates that it is now economically profitable to recover tungsten as a byproduct from the copper ores of at least three mines in the region... The monetary . value of the tungsten may even exceed that of the molybdenum if recovery costs can be minimized. It is, therefore, of utmost importance to understand the geochemistry of both elements. iue . oydnm rdcin n Arizona in production Molybdenum 1. Figure

PRODUCTION IN GIGAGRAMS* et f iea Rsucs Sae f Arizona. of State Resources, Mineral of ment 10 aa n esnl omncto fo te Depart the from communication recovered personal in molybdenum data of kilotons) (or Gigagrams rm l cpe oe mnd n rzn. ae on Based Arizona. in mined ores copper all from 16 2 - - 4 8 6 2 -- 4 8 T 95 90 95 90 1975 1970 1965 I960 1955 — — — - - - - i-O-O' YEAR O , 95 o 1975. to 1955

7 8

1.3 Possible Explanations of the Difference in • ' ' Behavior.- between Molybdenum and Tungsten

.Goldschmidt (1954.) suggested that the geochemical dissimilarities between molybdenum and tungsten are the result of the differences in free:energy of formation between the various isomorphic pairs. Urusov, Ivanova, and

Khodakovskiy (1967) examined the:thermodynamic properties . . of the different molybdates and tungstates in greater detail ; than .Goldschmidt/ and reached essentially the •• same conclu sion. According to the three Russian investigators, the geochemical separation of molybdenum and tungsten is caused by the difference in the stability of MeMoO^.and MeWO^ in + 2 +2 +2 the presence of sulfur (where Me is Ca • ,. Mn. , or Fe^ ') .

More recent free'energy data indicate that the tungstates of the divalent metals have more negative standard free energies of formation than their molybdate counterparts ..

(Table 3) „ However,/ it has: not been shown conclusively

that, molybdenite has a more negative standard free, energy

of formation than tungstenite. Published values for the

free energy of formation of tungstenite range from -298.to

.-193 kJ-mol- , and fall on both sides of the value for

. -1 molybdenite: -267 kJomol

Since GoIdschmidt1s explanation is at least par- ,

tially correct, the next step is to determine which atomic

properties are responsible for the thermodynamic differences

between the various oxide and sulfide isomorphs.( The first 9

Table 3. Values of the Gibbs free-energy of formation for selected molybdenum and tungsten compounds.

Gibbs free-energy ■ of formation Compound AGf. at 298.15 K in kJ-mol-1*

Molybdenite,, M0 S 2 -267 :

Tuhgs'tenite, WS^** . . -298 '. '

Ferromolybdate, FeMoO^ ■ -975

Ferberite, FeWO^ — 1054 -Vv :

Manganomolybdate , .MnMoO^ . -1090

Huebnerite, MnWO^ -1204 '

Powellite , CaMoO^ -1439 •

Scheelite, CaWO^ -1577

*Supplementary information and references are given in.Appendix H.

**The.value for tungstenite is suspect. .Published values range from ^193 to -^298 kJ = mbi"^. 10 three parameters normally considered in a comparison of any two elements are:

(1 ) the effective radius of each atom,

(2 ) its net electric charge, and

(3) the number of valence electrons in each of its

outer subshells.

However, in the case Of the tetrahedral MoO^~ and WO anions, the "three parameters for molybdenum and tungsten are essentially identical.. The electronegativity of an element is a quantitative measure of the interaction of these same.three parametersIn this instance, the;small . difference of 0 .1 between the electronegativities of molyb- . denum and tungsten cannot account for the observed separa tion of the two elements. Other elements in the .same:situa tion (e.g., Sr-Ba, Zr-H.f , . As-Sb>-'. and' Br-I) have; equal or greater differences in electronegativity, but do not exhibit such a:radical departure in geochemical behavior. Crystal field stabilization effects can also be ruled out in a comparison of the relative stabilities of MeMoO^ and MeWO^ because both molybdenum and tungsten are in.the hexavalent state and do not have.any electrons occupying the d subshell.

Several possible explanations of the difference in the geochemical.behavior of molybdenum and tungsten remain.

First, the neutral molybdenum atom has an "anomalous" electronic configuration unlike tungsten (Table 4}„ Molyb

denum is like chromium in this instance and prefers a half-

filled d subshell instead of a filled outer s subshell» The

situation .for molybdenum and higher Z transition elements

is complicated further by interelectronic repulsions and

imperfect electron shielding« As the net. result of these

phenomena, the energy levels of the (n-l)d and (n-1 )f

orbitals cross those of the ns and np orbitals at certain

points in the periodic table. - These orbital cross-over

effects produce perturbations in the ionization potentials

and bond strengths of several transition elements, and could

account for the more covalent nature of molybdenum.

Second, molybdenum might be able to form a metal-

metal.bond in. molybdenite with its 4d electrons that would

be stronger than the corresponding one formed by tungsten

in tungstenite with its 5d electrons. MoO^ and WO 2 both

have distorted rutile structures that are stabilized by

metal-metal bonds (Kepert and Vrieze, 1975). Unfortunately

little is known about metal-metal bonding in sulfides.

Third, MoO^ and WO^ .tetrahedra polymerize somewhat

. differently, in acid solution. In both cases the basic • .

structural unit is an octahedron of oxygen atoms with a

metal atom at its center. . When the oxygen octahedra poly

merize by sharing an edge or corner with one another (Figure

2), some of the oxygen bonds are protonated. Pi bonds may 12

Table 4. Electronic configurations of the neutral atoms„

At. .Shell N o . M ■ N ' 0 P

22 Ti 3s2 3p63d2 4s2

42 Mo 3s2 3p63d10 4s2 4p64d54f° 5 s1

74 W 3s2 3p63d10 •; 4:s24p'64d104f-4.;V 5s25p6 5d45f0 5g0 6s2 ; c Figure 2. The buildup of isopoly molybdate and tungstate anions from octahedra of oxygen atoms.

Cotton and Wilkinson, 1972. a, the structure of the paramolybdate anion (M07O 2 4 ) . b , the structure of the octamolybdate anion (Mo q 026) • One MoOg octahedron is completely hidden by the seven which are shown. c, the structure of the W12°46 un^t in the dodecatungstate anion. ■ 14 also form when the metal and oxygen orbitals overlap.

Cotton and Wilkinson (1972) suggest that the protonation helps to stabilize the octahedra by simultaneously weakening and lengthening the metal-oxygen bonds. It appears that the isopolytungstate anions may require more protonation than their molybdate counterparts. If this is. true, changes in the pH of a hydrothermal solution could cause the molybdate and tungstate anions to physically separate. CHAPTER 2

■GEOCHEMISTRY OF MOLYBDENUM, TUNGSTEN, AND TITANIUM .

2.1 Differences in Electronic Structure

Most of the chemical differences between molybdenum, tungsten, and titanium, can be attributed to either (1 ) the decrease•in the energy of a given atomic orbital with in creasing atomic number, or (2) differences in the number of electrons occupying the outer d and s orbitals. The key electronic subshells for the three atoms are underlined in

Table 4. The presence or absence of electrons in these outer subshells will determine the effective radius of.the atom in any crystal structure.,

Figure 3 represents, the energy levels of the 3d,

4s, 4p, 4d, 4f, 5s, 5p> ■.Sd,;- 5 f , a n d ;Bstorbitalstas : a func- •; tion of the atomic number, Z„ •Latter (1955) obtained the curves by using the Thomas-Fermi-Dirac method of the sta- .. ' ■/■■■ .. ' ^ „ ; ■ ■ . ■■■ . tistic atom potential to solve the Schrodinger wave equation.

The.curves help explain why the neutral molybdenum atom has an "anomalous" electronic configuration unlike tungsten, titanium, yttrium, and zirconium. Molybdenum would have four 4d electrons and two 5s electrons if its configuration were, analogous to that of tungsten„ Instead, the atom has five 4d electrons and ohly one 5s electron. The deviation

. : : - ■ - is ' ■ 0.1

CM 0.2

f 0.4 - J (r r 0 .6 - -N IV 0.8 f 1.0 V oT 5 E 20 X 5d o o 4.0 o (£ g 6.0 o3 cr t/) 8.0 10.0

20.0 20 40 50 60 70 8030 90 Atomic Number Figure 3. Energy levels of the intermediate n atomic orbitals as functions of atomic number. The curves were constructed from data obtained by Latter (1955) for the Thomas-Fermi-Dirac model. (1 Rydberg = 2.180 x 10~18 j) 17 from the normal filling pattern occurs because the 4d and

5s.energy levels cross at about Z = 4 1 (Nb). Similar cross overs are. observed for the 3d and 4s orbitals at Z = 24

(Cr), the 4f and 5d at Z = 57 (La), and the 5f and 6d orbitals at Z = 91 (Pa) (Figure 3. and Table 5).

The energy level crossovers are the result of the counterbalancing of electron penetration phenomena by either half-filled or completely filled subshell stabilization eff e c t s T h e configurational dif ferences . between titanium and chromium illustrate this • counterbalancing. The 4s . orbital of titanium has a lower energy -than:the 3d orbital . because the 4s electron occasionally penetrates the M shell.

As a general rule, the lower the angular quantum number,

%, of the electron, the. more penetrating, the electron will, be. Although penetration by the 4s electron only occurs during a small fraction of the 'total;, orbital, time, the decrease in orbital energy is considerable because the coulombic force of attraction between the nucleus and the electron is inversely proportional to the square of the distance from the nucleus. . In the case of "chromium, .. however,' the energy produced by the penetration of a second 4s electron is less than that gained from the half-filled 3d subshell. '

The sudden changes in the orbital filling pattern are also revealed by the deviation in the electronic density 18

Table 5. Deviations in atomic orbital filling.

Atomic Observed Expected Number Element. Configuration Configuration

24 Cr 3d5 4s1 3d4 4s2

29 Cu 3d104s1 3d9 4s2

41 Nb ' - . 4d4 ;5s:i : ■ 4d3 5s2

42 MO ■ 4d5 5s1 4d4 5s2

44 ■ Ru ' 4d7 5s1 4d6 5s2

45 ' - Rh ■ 4d8 .5s1 : . ::4d7: ss2

46,- . Pd 4d18 :■ ■ ■ 4d8 5s2

47 Ag 4d105s1 4d9 5s2

57 La' sa1 ; ; . 4i1 '

64 Gd 4f7 Sd1 ■ 4f8 .

65 . Tb. ■ 4f8 Sd1. . . 4f9 ,.

66 ■ • Dy : ; 4f9 Sd1 .;4f10 ■„

67 Ho . 4f105d1 4f1 1

68 Er 4f115d1 4f12

78 Pt 5d9 6s1 5d8 6s2

79 Au 5d18 6s1 5d9 6s2

91 Pa 5f2 ed1 6d 3 ■■

92 U 5f3 ed1 19 curves for the Group VIIA elements (Figure 4). The nuclear charge in this instance is simply the atomic number,. Z, and not the effective charge, Z*. The nonpolar covalent. radius determined from homonuclear bond length measurements is used as the radius, r.

One should avoid attaching too much significance to a given electronic configuration because the orbitals of the outermost shell.frequently hybridize when the atom is incorporated into a crystal structure„ For example, the 2 Cu II atom forms'four coplanar dsp bonds in CuO by pro- . - moting a 3d electron to a vacant 4p orbital (Evans, 1966).

This.phenomenon of orbital resonance hybridization is par ticularly important for molybdenum and tungsten because

they both have high atomic numbers with many closely spaced ' ■ outer orbitals and form chemical bonds.that are intermediate between the purely ionic, covalent,and metallic extremes. 4 2 In fact, the 4d 5s state of molybdenum lies only 10,966

cm (131,18 kJ

1958). In the tungsten atom, the unoccupied orbitals are : 5 1 even closer to the valency orbital. The 5d 6s .state of -

tungsten is just. 2.951 cm \ (35.30 kJ°mol - ) above:the 5d^

6s^ ground state.

Internuclear distances can be obtained from either

x-ray. diffraction patterns of:crystals, or. electron diffrac

tion studies of diatomic gas molecules^ However, the radius iue . lcrnc est pos o eeet i the in elements for plots density Electronic 4. Figure

SQUARE ROOT OF THE ELECTRONIC DENSITY, (~— IN (n m )~ ^ 4irr0 40 50 60 ■ • 30 -• 70 80 ■* h cnet f lcrnc est i discussed is (1971). density Sanderson electronic by of concept The orh ffh n sxh periods. sixth fifth, and fourth, 10 -- 1 0 UBR F UEMS SEL ELECTRONS SHELL OUTERMOST OF NUMBER 10 9 8 7 6 II 5 4 3 2 12 Mo + Cd Zn

20 21 of an atom .is more difficult to determine because the electronic distribution of any atom is affected by the electric fields'of its neighbors. It is not surprising then that several, sets of atomic radii 'have.been proposed since Lande (1920) first published values for the alkali haiides. Some of.the different radii for titanium, molyb denum, . and. tungsten are compared in Table 6 . Notice; that the three.elements have, essentially identical radii. The value. ■ of 1 the:ionic•radius not only depends upon the oxida- ■ tion state of the atom, but also upon the number of anions grouped around each cation. The reader should refer to the table.of correction factors published by Pauling (1960) when the ligancy differs from the octahedral value, of 6 „

The ele.ctronegatlvities: of .titanium, : molybdenum,' and tungsten, also, are very much alike., but one should be

cautious about generalizing here because minor variations

in electronegativity may produce considerable differences in bond strength. On the other .hahd>. a. difference: of-only

0.1 between the Pauling values (Mo =1.8 vs. W = 1.7) can hardly account for the wide difference in geochemical be

havior in the two elements. Pauling (1960) has shown that

the partial ionic contribution to a chemical bond between

two given elements can be determined from their respective

electronegativities. Table 7 compares the partial ionic

character of different bonds formed by the three transition Table 6 . Various covalent, ionic, and metallic radii* for titanium, molybdenum, and tungsten.

The octahedral covalent radius for Ti(4) in TiS„ is 0.136 nm. The titanium forms six sp^d^ hybrid bonds (Pauling, 1960, p. 251).

: ; . ' . : ■ ; . ' \ ' ■ ' Ti " Mo ■ W

Metallic radius assumed equal to half of 0.14478 0.13626 0.13705 the observed homonuclear bond length (In «: form, 298 K ternational Union of Crystallography, 1952). This radius is for all practical purposes 0.14318 equivalent to the non-polar covalent radius 6 form, 1173 K of Sanderson.(1971).

Single-bond metallic radius of Pauling 0.1324 0.1296 0.1304 (1960) The number in parentheses is the (4) (6) (6 ) metallic valence. The metallic radius for a ligancy of 12 is shown underneath for . 0.1467 0.1386 0.1394 comparison.

Crystal ionic radius of Ahrens (1952). The (1) 0.096 0.09 3 [0.093] number in parentheses is the ionic valencei (2 ) 0.094 [0.091] [0.091] Values in brackets are interpolated. The (3) 0.076 [0.077] [0.077] cations are in octahedral coordination. (4) 0.068 0.070 0.070 (5) :---- [0.065] [0.065] (6 ) — — . 0.062 0.062

- *A11 radii are given in nanometers. 23

Table 7. The partial ionic character of different bonds formed by titanium, molybdenum. ^ and tungsten.

Pauling Percent Ionic Electronegativity Character Bond Difference P P'

Ti-F ' . 2.5 ■ 79% 62% Ti-Cl 1.5 . 43 . 32 Ti-Br 1.3 35 ■ 27 Ti-I 1.0 22 20 Ti-0 . 2.0 63 46 Ti-S 1.0 22 20

Mo-F . 2.2 :• 70 52 • M o - C l ' 1.2 . 30 24 Mo-Br . 1.0 22 20 MO-1 0.7 . ' 12 13 , Mo-0 ■ 1.7 . ' 51 : 37 Mo-S . 0.7 . 12 ' ■ - 13.

W-F •■■■ . 2.3 73 55 w-ei 1.3 35 27 W—B x . 1.1 26, 22 W-I - 0.8 . 15 15 W -0 1.8 5:6 40 . W —s 0.8 , 15 . : 15 : . 24 metals. The percent ionic character, p, of each chemical bond was estimated from the following two empirical formu

(1) Pauling (1960) and 2 (2) p*. = 16 |xA-Xg.| + 3.5 IxA -xB Evans (1966)

■ tivities. Notice that in both cases the W-0 bond is more ionic than the Mo-0 bond, and that the Mo-S bond is more covalent: than .the Wr-S bond. 1 - This : f act::suggests ; that • the heat of. formation of tungstenite should be : slightly:; more negative than that of molybdenite.

2.2 Effect of Differences in Nuclear Structure ■ on the Abundances of the Three Elements /• .

Let us next examine how the nuclear structures.of the different titanium, molybdenum, and tungsten isotopes relate, to their abundances in the earth. At this point it is important to emphasize the difference between:

(1 ) bulk earth abundances of the elements based on chemical analyses of meteorites and various planetary dif

ferentiation models, and .

(2 ) crustai abundances based on: chemicalanalyses • of : ■

surface rocks.

Ronov and Yaroshevsky (1972) suggest that molybdenum

and tungsten occur in almost equal amounts in the continental 25 crust. Their crustal values are compared below with es timates made by Ganapathy and Anders (1974) for the earth as a whole.

• Continental Crust 'Earth as a Whole

Ti 5,650 ppm 1,030 ppm Mo 1.2 2.96 W 1.25 0.250

Mo/W ' 1.0 ' 12.

Titanium is apparently enriched in the crust, while molyb- •" denum is depleted. The meteorite analyses in Table 8 tend ; to support the 12:1 estimate of Ganapathy and Anders, and . clearly demonstrate that tungsten in more siderophile and

less chalcophile than molybdenum. For.almost a century scientists have assumed that the average composition of meteorites closely approximates the bulk composition of the earth. . If this hypothesis is correct, the Mo/W ratio for . ■ the earth as - a whole should be a t .least 3 :1 and probably

7:1-

Few reliable analyses of molybdenum and tungsten in

unmineralized crustal rocks exist because the abundances

of the two elements are either below or very close to the

detection limits of the more common analytical techniques.

Flanagan. (1973 and .1976) has compiled analytical data on :

33 of the whole rock standards used by laboratories through

out the world. Of these 33 standards, only 11 have been

analyzed for both molybdenum and tungsten. Table 9 is a Table 8 . The concentration of molybdenum and tungsten in different phases of meteorites„

Imamura and Honda,1976.

Mo (ppm) W (ppm) rTV'k+---»'1lotax jmo Mn Meteorite Type Metal S ilica te T ro ilite Total Metal S ilica te T ro ilite Total Total W

Chondrite Kesen H4 4.3 0.91 2.7 1.7 1.7 0.097 0.083 0.40 4.3 Yondzu H4,5 4.1 0.23 2.6 1.1 0.92 0.031 0.090 0.21 5.2 Richardton H.5 4,05 0.41 3.6 1.2 0.80 0.058 0.013 0.20 6.0 Bruderheim L6 6.41 0.34 3.5 1.26 1.53 0.041 0.084 0.17 7.4 Peace River L6 5.9 0.70 5.1 1.31 1.47 0.038 0, 016 0.16 8.2 Holbrook L6 15. 0.76 9.5 2.6 1,20 0.13 0.23 0.22 12. St. Severin LL6 3.8 0.65 3.5 0.99 1,3 3 0.34 0.26 0.36 2.8 1 1 1 H Allehde CV3 ,V4yO;.;.; — 2.2; •—• 2,2 0.28 0 0.17 13.

Mean 7.4

Iron

Odessa IA 6.4 — 2.26 7.8 0.94 ' — 0.24 0.96 8.1

K) Table 9 Titaniuift, copper, molybdenum, and tungsten in U.S. Geological Survey Standard Whole Rocks.

Abstracted from Flanagan» 1971. G-l, Granite from Westerly, Rhode Island; G-2, Granite from Westerly Rhode Island; GSP-1, Granodiorite from Silver Plume, Colorado; AGV-1, Andesite from Guano Valley» Lake County, Oregon; PCC-1, Peridotite collected as stream boulders from Caradero ultramaficmass, Sonoma County, California; DTS-1, Dunite from: Twin Sisters area, Hamilton, Washington; BCR-1, Basalt from Columbia River (Yakima Type)/ Washingtoh, Oregoh; W-l, Diabase from Centerville, Virginia. Theeirors in the titanium and copper values range from about 3 to 10% for a stahdard deyiatioh of one sigma. The molybdenum and tungsten values are only averages that depict relative orders of magnitude.

Granite Granite Granodiorite Andesite Peridotite Dunite Basalt Diabase G-i\. G-2:- GSP-1 AGV-1 PCC-1 DTS-1 BCR-1 W-l

TiO (wt.%) 0.26 0.50 0.66 1.04 0.015 0.013 2.20 1.07 Ti (ppm) 1,600 3,000 3,960 6,230 90 78 13,200 6,410 Cu (ppm) 13. 11.7 33.3 59.7 11.3 7.0 18.4 n o Mo (ppm) 6.5 0.36 0.90 2.3 0.2 0.2 1.1 0.57 W (ppm) 0.4 0.1 0.1 0.55 0.06 0.04 0. 40 0.5 Cu/Mo 2.0 33. 37. 26. : : 57. . ' 35. 17. 190 cu/w 33. 120 330 110 190 180 46 220 Mo/W 16 4 . 9. 4.2 . 3- , 5. 2.8 ,1. Ti/Cu 123 256 119 104 8.0 11. 717. 58.3

ro ' 28 summary of Flanagan1s. findings for eight igneous rocks.

The analyses were done primarily by conventional x-ray fluorescence, optical emission spectrometry, and colori metry. For a detailed discussion of the molybdenum and tungsten colorimetric procedures, the reader may refer to the articles by Chan and Riley (1966 and 1967).

Selected properties of the different stable iso- : topes of titanium,", molybdenum, and., tungsten are compared "; in Table 10. Two conclusions about the abundances of the three elements in the earth as a whole can be drawn from this table. First, titanium is much more abundant than molybdenum in the earth because titanium has a considerably,

lower atomic number and a moderately high set of binding energies per nucleon. Second> molybdenum must be more

abundant than tungsten for the following reasons:

(1) Molybdenum has only 42 protons, while tungsten has 74 & ...

(2) The thermal neutron cross-sections of the dif

ferent molybdenum isotopes tend to be smaller than those

for tungsten.

(3) Molybdenum has two more stable isotopes than

tungsten (7 vs. 5). 92' ■ (4) One of the isotopes of molybdenum (^Mo) is. singly

"magic". Table 10. Isotopic properties of titanium,, molybdenum, and tungsten.

Natural abundance and cross-section data are taken from General Electric Company (1970) and Lederer, Hollander> and Perlman (1967). Values of the binding energy per nucleon were calculated from mass excess data given by Lederer et al. Values of the binding energy of the last neutron were calculated from the total binding energies of See g e r .(1972). 9?Mo is singly ,fmagic", while §QTi is singly "semi- magic".

Binding Binding Energy Natural Thermal Neutron Energy per of the Protons Neutrons Mass Abundance Cross-Section Nucieon Last Neutron

Ti 22 - 24 ' 46 ),93% 0.6 barns 8.6,564 MeV 12.8 MeV 25 47 7.28 1.7 8.6611 8.8 26 48 73.94 7.9 8.7229 12.0 27 49 5.51 1.9 8.7111 8.2 28* 50 5.34 0.14 8.7558 10.6 Mo 42 50 92 15.84 <0.3 to 93 8.6578 12.2 <0.006 to 93m 52 94 9.04 na 8.6623 9.8 53 95 15.72 14.4 8.6488 7.3 54 96 16.53 1 8.6541 9.2 55 97 9.46 2 8.6351 6.7 56 98 23.78 0.14 8.6352 8.7 58 100 9.63 0.20 8.6047 8.4 W 74 106 180 0.14 ~10 8.0241 7.9 108 182 26.41 20.7 to 183m 8.0179 7.6 0.5 to 183 109 183 14.4 11 8.0079 6.3 110 184 30.64 1.8 to 185 ■ 8.0047 7.3 0.002 to 185 112 186 28.41 36 7.9883 7.0

k) io ' ■ 30

(5) The binding energy per nucleon of any molybdenum

isotope is greater than that of any tungsten isotope.

(6 ) The last neutron binding, energies of the different molybdenum isotopes tend to be greater than those for

tungsten.

If the earth has formed by the same process as the ' meteorites, molybdenum and tungsten should be more;abundant

in the core than in the crust. It appears that .Ronov and

Yaroshevsky (1972) have overestimated the crustal abundance of tungsten, and that the 1:1 crustal Mo/W ratio is in

.error. Based on the isotopic differences and the few ' :

U.S.G.S. whole rook analyses that are available, this ratio

should be about 5:1, 'However, even a 5:1 ratio would in

dicate that tungsten has been enriched in the•crust relative

to molybdenum.

2.3 Molybdenum and Tungsten Minerals .

Isomorphism and diadochy strongly influence the .

primary molybdenum and tungsten mineralization in porphyry

copper deposits. In the case of molybdenite, minor amounts

of tungsten and rhenium substitute for the molybdenum, while,

selenium and tellurium substitute for the sulfur. Molyb

denite , tungstenite, - and rhenium disulfide belong to the '.

same hexagonal space group: .'. PG^/mmc (194) and have almost

identical cell parameters (Table 11). Notice also that the

Group VIA selenides are isostructural with the sulfides. , - . 31

Table 11. Comparison of the cell parameters of molybdenite, tungstenite, and related structures.

a in nm c in nm c/a Z* o o '

MOL YB DEN ITE, MoSg • Hexagonal (2H]_) . Locality not given... Dickinson and Pauling (1923)

0.315 ± .002 1.230 3.005 2

■MOLYBDENITE-,.'MoS2 ». Rhombohedral (3R) . From USSR, locality ' not given. Kruglova, Sidorenko, and Polupanova (1965)

0.315 ± .001 1.836 ± .005 5.829 3

TUNGSTENITE, WSg. Hexagonal (EHp) .' From Lyangar, western Uzbekistan^ USSR. Rimskaya-Korsakova and Troyanov - (1956)

0.3157 ± .0004 1.2384 ± .0009 3.9227 2

RHENIUM DISULFIDE,^ ReS2« Hexagonal (2Hy) . Synthetic. Arutyunyan and Khurshudyan (1971)

0.3160 1.2226 3.8690 2

MOLYBDENUM. DISELENIDE, MoSe2. Hexagonal (ZH^). Synthetic. Brixner (1962) '

0.3288 ± .0005 1.2900 ± .0005 3.9234 .2

MOLYBDENUM .DlSELEN.IDE, MoSe2 . ' • Rhombohedral (3R) , . Synthetic. . . Data at 1820 ± 50 K and 4.0 ± 0.1 GPa. Towle et al. (1966) ,

, 0.3292 1.9392 5.8906 3 .

*Z is the number of gram formula weights per unit cell. . 32

All six compounds are lead-gray in color, opaque, and have a metallic appearance. Molybdenite has a slightly more greenish streak than tungstenite. The densities of tungstenite and rhenium disulfide are, of course, much greater • than that of molybdenite (7.732 and 7.506 vs. 4.979 g/cm3).

Chukhrov et al. (1970), Frondel and Wickham (1970), and Ayres (1974) have x-rayed molybdenites from various environments and have found that about 10 % of the specimens were either of; the 3R polytype or a mixture of the 2H^ and

3R polytypes. Three of the molybdenites in the Frondel and Wickham study'were from southeastern Arizona. The two from the Santo Nino mine were both 2H^ poly types «i The. third specimen,.a mixture with a 2H^/3R ratio of 9:1, was from the old mining town of Helvetia.0 Ayres has suggested that the 3R polytypes have:a greater rhenium content than the 2H^ polytypes.

Wolframite is sometimes found with the molybdenite and chalcopyrite in the Arizona porphyry copper deposits, but it is much less abundant. Wolframite specimens from molybdenite-rich copper ores have a greater iron to man ganese ratio than specimens from ores that have no molyb denite (this study). It is strange that no molybdenum - analogue of the ferberite-huebnerite solid solution series has been reported in the mineralogical literature. As . 33

mentioned earlier, FeMoO^ and MnMoO^ can both be readily

synthesized, in the laboratory and are extremely stable

compounds. Furthermore, chemical analyses of wolframite

performed in connection with this study indicate that molyb

denum is excluded from the structure during the ore-forming

process and only occurs in trace amounts in natural crys- /

■ tal.s e

In contrast, both powellite and scheelite formed -

in skarns when quartz monzonite or granodiorite stocks

intruded Paleozoic limestones. . Most of the., powellite is

found in - the supergene.zones as an alteration product.of ; .

molybdenite and scheelite (this study). This secondary

powellite can occur as a vug filling, a pseudomorph after

molybdenite, or a thin coating on the silicate crystals ..

adjacent to an altered bleb of molybdenite. All three forms

of powellite can be seen in the garnetites of the ANAMAX

mine at Twin Buttes. The scheelite. On the other hand, is.

a primary ore mineral, and is usually associated with pyrite, ,

chalcopyrite, galena, sphalerite, or molybdenite. The

tungstate is not restricted to skarns, and often occurs in

quartz veins, breccia. pipes , and pegmatites«, This dif-

■ ference in genesis between powellite and' scheelite is .- rather ,

surprising since the two minerals are end-members of a

continuous solid-solution series as indicated by laboratory 34. synthesis (Hsu, 1977) . Powe.ll.ite is apparently much rarer than scheelite in nature.

Crystals of scheelite and powellite show a wide variation in color. The scheelite of southeastern Arizona, ranges from pure white (Twin Buttes) through pinkish orange

(Texas' Canyon) to deep tan (Carr Canyon). Some Korean scheelite, on the other hand, is brownish-black. Powellite is commonly greyish-white (e.g., af Twin Buttes and

Helvetia), but may be almost any color. Hsu and Galli

(1973) .have even reported finding a green variety of..powe 1- ... lite in an. altered rhyolite near Tonopah, Nevada.. Pure . scheelite fluoresces:bright blue under short wave ultra- - violet light, while scheelite with 0.35 to 1.0 weight percent molybdenum. has a .bluish-white fluorescence. (McLaren, •

1943).. Powellite and scheelite with greater than 1.0 weight percent molybdenum fluoresce yellowish-white to golden yellow.

Hsu and. Galli (1973) have analyzed more than 100 • specimens of scheelite and.powellite from Nevada and

California. They observed that the composition of scheelite from contact-mbtasomatic deposits:, ranged from 0 . 01 to 54 mole percent CaMoO^, but that scheelite from pegmatites ; and hydrothermal veins normally contained less.than 0.05 : mole percent CaMoO^. The two investigators did not find primary powellite in any of the deposits studied. The. : 35 observations of Hsu and Galli apparently should apply to the scheelite and powellite in southeastern Arizona, with one exception. The spectrographic.analyses in Appendix E suggest that the scheelites from hydrothermal quartz veins in Arizona contain slightly more molybdenum than those from Nevada.

Several secondary molybdenum and tungsten minerals occur in the upper oxidized zones of the porphyry copper deposits (Figure 5). ■ The most common is ferrimolybdite

(Fe^Mo^O^ ’ Excellent examples of molybdenite al tering to microcrystalline, canary-yellow ferrimolybdite . were .seen by the author in the Copper Hill breccia pipe at Copper, Basin,: the Childs-Aldwinkle breccia pipe at Copper

Creek, the skarns of the East pit at Twin Buttes, and the chloritized Oracle Granite (quartz monzonite) at the Rare

Metals;:,mine>;-northwest of S a n . Manuel. .. The rare tungsten . T T T T T analogue, f erritungstite [CagFe^, Fe^ ; (WO^) ^ ° 9^ 0 ] , is also bright yellow in color and forms in limonitic gossans as an alteration product of scheelite and wolframite

(Richter, Reichen, and Lemmon, 1957). Unfortunately, there are no published accounts of the occurrence of ferritungstite in southeastern Arizona.

Wulfenite (PbMoO^) often forms in the oxidized parts of galena-sphalerite-chalcopyrite-rich quartz veins. • 36

TZ ! TTa v a j o APACHE (

/CAVE \ * CREEK ( !J \_ /\ PINTO VALLEY i MARICOPA \ / A \J > K > S A \ \ GREENLEE i------— • — • -A# ^INSPIRATION, COPPER CITIES, j SUPERIOR \ AND SLEEPING BEAUTY MTN. O O •n ------i a \ j i < X LU RARE METALS A \7® MiNE'i ARAVAIPA j 8 s _ \ / i 9 \ E FLORENCE LEAD SILVER® L»*» \ < LU

\ MILDREN ^TWIN BUTTES ! OD0S CA8EZ:AS 4STEPPE 'y j TEXAS CANYON @ I X .HELVETIA ® PEARCE HILLTOP

Es p e R«» z . i „ 5 on ? 7 t11-w" ec,< a 6 i r e s „„ i MADERA CANYON A Q OGLEESON : •-...4^ GLOVE* i TOMBSTONE i o S o o ee,seEE ! 4 SANTA CRUZ “CARRI CANYON

0 10 20 30 MILES 1 rrd

25 50 KILOMETERS

Figure 5. Some occurrences of secondary molybdenum and tungsten mineralization in southeastern Arizona.

Based on Anthony, Williams, and Bideaux, 1977. ® VJulfenite 0 Lindgrenite A FerrimOlybdite O Stolzite q Cuprotungstite Some of the well-known localities (Anthony, Williams, and

Bideaux, 197.7) include:

(1) the "79" mine in the Dripping Spring Mountains,

Gila County;

(2) the Mammoth-St. Anthony mine at Tiger in Pinal

County ?

(3) the Old Yuma mine south of Contzen Pass in the

Tucson Mountains of Pima County;

(4) the Mildren and Steppe claims on the west flank of the South:'Comobabi Mountains-, Pima County;

(5) the Hilton and Total Wreck mines in the Empire

Mountains of Pima County;

(6 ) the Glove mine in Cottonwood .Canyon, Santa Rita

Mountains, Santa C r u z County;

(7) the Domino.mine in Three R Canyon, Patagonia

Mountains, Santa Cruz County; and

, (8 ) the.Defiance, Mystery, and Silver Bill mines at ■

Gleeson in Cochise County.

Many of these secondary deposits are believed to be post-

Eocene in age. The pale yellow to bright orange molybdate is commonly associated with cerussite (PbCO^), vanadinite

[Pbg (VC>4) 3CI] , and mimetite [Pb,. (AsO^) gCl] i. On occasion, it also occurs with descloizite [PbZnVO^(OH)], mottramite

[PbCuVO^(OH)], or native silver and gold (Anthony et al., 38

1977). : Some wulfenite contains as much as 8% W along with minor amounts of V, Cr., As, and Sb (Williams, 1966).

Strangely enough,:very little wulfenite has-been found in the oxidized zones of the major porphyry copper deposits. The source of molybdenum for the wulfenites of southeastern Arizona remains an enigma. However, the study by Creasey (1950) of the mineralization at the Mammoth-

St. Anthony lead-zinc deposit has provided some insight into the formation of.wulfenite. Creasey observed that the main sphalerite-galena-chalcopyrite-rich quartz vein at . the, mine had undergone faulting and several stages of mineraliza tion and oxidation before the wulfenite and vanadium minerals were - formed. - Hypogene v (?) • solutions of molybdenum■ and vanadium were later introduced along the faults and vein segments where they reacted with cerussite and possibly anglesite to form.the wulfenite. Since the 65 m.y. old

San Manue1-Kalamazoo porphyry copper deposit lies only.3 km to the southwest and is older than the Mammoth-St. Anthony . deposit (post-Cloudburst Fm., Creasey, 1967), the San

Manuel ores may have been a possible source of the molybdenum, --

.. The tungsten analogue of wulfenite, stolzite . (PbWO^) is much rarer. Pale yellow crystals of stolzite, 1 mm un length, have been found at the Bluebird (or Primos) mine in the Little Dragoon Mountains along with chalcopyrite, 39

sphalerite, huebnerite, scheelite, fluorite, and galena

(Palache, 1941). The rare tungstate also occurs in the Dos

Cabezas mining district on the northwestern flank of the

Dos Cabezas Mountains, and at the.Reef mine in the Huachuca

Mountains (Anthony et al„, 1977)„ In both instances,

millimeter long crystals of white stolzite have formed in :

quartz veins that contain scheelite, galena* and pyrite.

Intermediate members of the htolzite-wulfenite series have

' been recognized in a few districts* : ■Stolzite from a .

prospect on the east slope of Day Peaks, about 2 .8 km '

southwest of the Copper Cities pit, contained 9% MoO^ .

(Faick and Hildebrand, 195.8) * / • . •

• Lindgrenite [CUg(MoO^)2 (OH)2 ] and cuprotungstite

■ [Cu2W0 4 (OH)2 ] have both been identified in southeastern

Arizona. Lindgrenite. has been found with chrysocolla,

malachite, azurite, and other: secondary copper minerals

■ in the oxidized zone of the Live. Oak pit at the Inspiration

mine (Olmstead and Johnson, 1966). .Other localities for

lindgrenite include: the Esperanza pit, the Childs-

Aldwinkle mine, the Hull claims south, of Ray, and Superior

(Anthony, et al. , 1977) .. Cooper and Silver (1964). have re- .

ported finding cuprotungstite in a huebnerite-bearing

quartz vein that cuts the Texas Canyon QUartz Monzonite ::

about 8.00 m southwest of Johnson Camp. Cuprotungstite has..

also been discovered on the 200 ft level of the abandoned Helvetia mine in the Santa Rita Mountains (Anthony et al.,

1977) .

. Little information is available on .the small.amounts of tungstite (WO^'H^O) and molybdite (MoO^) that have formed in some of the deposits <,

. 2.4 Laboratory Synthesis of Molybdates and Tungstates

The different molybdates and.tungstates of man ganese and iron can be synthesized in the laboratory by a variety of precipitation and.hydrothermal crystallization . methods. Shapiro and Yurkevich (1963) have prepared ferromolybdate.(FeMoO^) by precipitating the compound from a cold, aqueous, solution of NagMoO^ with FeSO^°^H^O. This procedure for precipitating ferromolybdate serves as a model for synthesizing at least 20 other transition metal molybdates and tungstates.

- In aqueous solution, the alkali metal molybdate ' salts readily dissolve to form a complex equilibrium as

semblage of polymerized anions: Figure 7= Histogram of K-Ar dates for copper”.molybdenum- tungsten mineralization in southeastern Arizona,

The sources of this data are listed in Appendices A and B,

No o on Figure:

Porphyry Deposits

Al Copper Cities mine A2 Inspiration and Miami mines A3. Pinto Valley mine A4 Ray mine A5 San Manuel-Kalamazoo orebody A 6 Copper Creek orebody A7 Poston Butte orebody A 8 Sacaton mine A9 Silver Bell mine A10. New Cornelia mine All. Sierrita-Esperanza orebody A12 Safford orebodies A13 Jhus Canyon stock (subeconomic)

Contact Metasomatlc Deposits Associated with Porphyritic Intrusives

Bl Christmas mine B2 Lakeshore mine B3 Helvetia-Rosemont orebody B4 Twin Buttes mine B5 Pima-Mission-Eisenhower-San Xavier mines

Vein Deposits or Pegmatites

Cl Pinal. Ranch claims C2 Rare Metals mine (abandoned) C3. Providencia Canyon claims C4 Texas Canyon claims C5 San Juan Canyon claims C6 Las Guijas mine (abandoned) Cl Reef mine (abandoned)

Contact Pyrometasomatic Deposits

D Johnson Camp 41

The relative, amounts of each species depend strongly on both the pH and the redox potential of the solution„ In the transition from an alkaline medium to an acid one, the molybdate polymerization increases, until finally yellow crystals of MoO^'ZH^O precipitate out of solution at a pH of 0.9. The nature and structures of the different poly- . molybdate anions in solution remain controversial, and need further investigation.

A similar,„but more, complicated^ phenomenon occurs with tungsten. Some of the isopolytungstate anions that .: have been identified to date include: paratungstate-A>

[W 6D 17 (OH) 5 ? paratungstate-B, CW ]_2Q36 10 ^ : ” ""12 metatungstate^.' metatungstate,

[W 12°38 ^0H) 2^ 6; an

The structure and properties of the. isopoly compounds of molybdenum and tungsten have been summarized by Tsigdihos and Hallada (1969), and Cotton and Wilkinson (1972). Ac- -2 -2 cording to Cotton and Wilkinson, the MoO^ and WO^ anions are both tetrahedral in aqueous solution„ When. polymerization occurs, the.tetrahedra transform into octahedra, which can then link in three dimensions by sharing corner oxygens.

In addition, at least 34 elements can substitute for the central molybdenum and tungsten atoms, forming complex heteropoly anions. The different heteropoly - 42

compounds of molybdenum and tungsten have been reviewed

by Tsigdinos (1969) .

The experimental data of Shapiro and Yurkevich

(1963) show that the precipitation of ferromolybdate is

.maximized when the pH of the mother liquor is maintained '

within the narrow limits of 6.5 to 5.5. When, the pH falls . + 2 below 5.5, the Fe cations reduce the bexavalent molyb

denum. When the pH is greater than 6 .5, Fe(OH)2 precipi

tates along with the FeMoO^'ZHgO. At a pH of 6.0, the

yield of ferromolybdate is approximately 94%. Similar

phenomena are observed during the synthesis, of other transi

tion metal normal molybdates. Table 12 gives the optimal

pH values, for some of these precipitates.

During an investigation of the aqueous chemistry

of molybdenum.and tungsten, the author used techniques

cipitate amorphous quantities of FeMoO^, MnMoO^, FeWO^,

and MnWO^. The following procedure was used in the syn

theses :

(1) Aqueous 0.10 molar solutions of Na^MoO^° ZHgO,

Na2WO^ °2H20, FeSO^ °VHgO, and MnCl2° 4H20 were prepared from

the salts. In order to prevent the precipitation of Fe(OH)2

and Mn(OH)2, the pH values of the molybdate and tungstate

solutions were adjusted to 6.2 with 0.10 MHC1. Thermo

dynamic calculations indicate that Fe(OH)2 will precipitate 43

Table 12= Optimal pH values for the precipitation of selected transition metal normal molybdates =

After Shapiro and Yurkevich, 196 3=

Compound Optimal pH

NiMo0 4 7.0

CdMoO. 7.0 4 CoMoO4 6 = 0

from a 0.10 molar solution of ferrous iron at a pH of 1.1.^,

and that .Mn(OH)£ will precipitate from a 0.10 molar solu

tion of manganous ion at a pH of 8.1^.

(2) When an aliquot of the tungstate solution was added

to an equal volume of the ferrous sulfate solution, a

. voluminous, ochre-colored precipitate formed immediately...

' (3) The precipitates were filtered, dried, and then■...

analyzed by x-ray diffraction." All four compounds were

amorphous.

The trivalent metals , strangely ' enough., form two

types of molybdates and tungstates. The first, or normal

.type, is illustrated by ferrimolybdite: Fe^(MoO^)^ °nHgO.

Ferfimolybdite is formed in nature by the reaction of

pyrite with molybdenite under supergene conditions, and is ' ^ 1 ■ TTT . a s so ci a ted wi th.; jarosite [KFe^ . (SQ^) ^ (OH) ^ ] , gOethite . .

. [FeO (OH) ] , and various limonites. .Kerr ,. Thomas, and

Hanger (1963) have been able to synthesize a yellow, crys- -

talline compound that closely resembles natural ferrimolyb

dite by adding a 0.7 molar solution of FeCl^’SHgO to an

. acidified 0.1 molar solution of N^MoOy^H O^ end-then

. heating' the mixture' to .333' Kl' L

In the second type of compound formed by the tri- .

valent metals, the'central molybdenum.or tungsten atoms are

apparently in the +5 -oxidation state. CrMoO^ and CrWO^ are 45 examples. of this type. These two compounds were first

synthesized, by Doumerc, Bouchard, and Hagenmuller (1975).

Doumerc and his colleagues reacted chromic oxide with•

stoichiometric mixtures of either Mo'C^ + MoO^ or Mo + MoO^ at 1273 K in a sealed tube. The three investigators then repeated the experiment, using tungsten in place of molyb denum. The resulting crystals both have monoclinic sym metry, C2/m, and are isombrphs of AIWO^. ' Preliminary , evidence Suggests that:the +5 oxidation . state is stabilized 1 1 when: the 5d . electrons of tungsten (or the 4d electrons of molybdenum) form W-W (or Mo-Mo) bonds.

During the last two decades, several Russian crystailographers have developed a series of techniques ■ -;

for growing crystals of different molybdates and tung-

states under hydrothermal conditions. . Anikin (1957),

for example, was able to produce 0.3 to 0.5 mm crystals of scheelite by dissolving amorphous CaWO^ in a 4% solu

tion of NaOH; and then leaving the solution in an autoclave

at a temperature of 653 K and a pressure of 30 MPa for 50 hours. Dem‘yanets (1971) t using hydrothermal procedures

solutions were less suitable media. Table 13 is a list of

the known molybdates and tungstates formed by the divalent Table 13o Known and predicted molybdateg and tungstates formed by the divalent ... metals, .

Adapted from Young and Schwartz (1963), Dem"yanets (1971), Sleight (1972), and Jeitschko and Sleight (1972) and 1973). Minerals: a, ferberite; b, sanmartinite; c, huebnerite; d, pqwellite; e f scheelite; f f wulfenite? g, stolzite; h, raspite. [ ] - existence predicted.

MOLYBDATE TUNGSTATE Ionic Structure Type _____ Structure Type_____: Atomic Divalent Radius Wolframite Scheelite Other Type Wolframite Scheelite Other Type No. Cation in hm P2/c 14,/a and Space P2/c I4^/a and Space Group Group

12 Mg 0.066 MgMo04* rigiMbp4-rC2/ffi MgW04 28 Ni 0.069 NiMo04* NiMo04-C2/m NiW04 27 Co 0.072 Co#o4* CoMo64r-C2/m CoW04 29 Cu 0.072 [CuMo04 CuMo04-C2/m CuWO. 26 Fe 0.074 FeMo04* FeMo04-C2/m FeWp 4, 30 Zn 0.074 ZnMo04* ZnMo04-C2/m ZnW04 25 Mh 0.080 MnMo04* MnMo04-C2/m MnMP: 50 Sn 0.093 [SnM004] [SnWP4] SnW04-P213 48 Cd 0.097 CdMo04 CdWP4 20 Ca 0.099 CaiMoO.4 .d GaWp4e 63 Eu 0.109 [Eu Mo 0 4 ] E u W P 4 80 tig 0.110 HgHo04-C2/c HgW04-C2/c 39 Sir 0.112 SrMoO.4 SrW04 82 Pb 0.120 PbMp04 PbW04g PbW04-P21/nl 56 Ba 0.134 BaMoO, BaWO.

^Synthesized at 1173 K and 6.0 GPa. 47 metals, Klevtsova and Klevtsov (.1975) have solved many of

the structures of the double molybdates and tungstates

formed-by. the univalent and trivalent metals, and have set

up a classification' system- that incorporates at least 40

crystal structures and more than .15 crystal types.

Large, single crystals of the normal molybdates

and tungstates have also been grown from the melt. Nassau

and Van Uitert (1960) produced crystals of scheelite up to

18 cm in length and 1,3 cm in diameter using the Czochralski method. The growing crystals were rotated on a platinum wire, at 12 rpm and continuously pulled from the 1873 K melt .

at a rate of 70 mm/h. Van Uitert and Preziosi (1962) have

used variations of this technique to grow single crystals

of CaMo04, SrMo04, BaM004 , PbMo04 , MgW04 , ZnWC>4 , and CdWQ4 ;

The: following statements summarize the behavior of -

molybdenum and tungsten.in aqueous solution:

(1) In the pH range between 1.0 and 7.2, stable complex molybdate and tungstate anions are formed by the polymeri-

— A ■ mm zation of MoGg and WOg octahedra.

(2) Polymerization of the molybdate and tungstate anions

does not. occur when the pH is more basic than 7.2 in both

cases. ;

(3) MoO^”2^0 and °2^0 crystallize from solution

when the pH is more acidic than 1.0.

(4) Molybdenum and tungsten form anionic complexes with

the halogens, oxygen, and other elements that have a 48

Pauling electronegativity greater than 2.4. Examples of the chlorine complexes include: MoClc~,. WC1 ~ , Modi ~2 , WC1 ” 2 , b o b o -3 -9 MoClg . and MoOCl^ . The hexahalides of molybdenum and tungsten decompose rapidly in hot water to the oxyacids and complex oxyhalide anions. The tetrahalides rapidly oxi dize as well as hydrolyze (Fergusson, 1967). Neither group of compounds is apparently stable in a hydrothermal type of environment

(5).. Oxidation-feduction , reactions, p l a y : an important ■ role in molybdenum and tungsten chemistry. Moreover, . several . aqueous molybdenum and tungsten . complexes are . known ... to undergo disproportionation. :These peculiar blue colloids are not well understood, but appear to be a mixture of pentavalent and hexavalent. oxide-hydroxides:

j—• molybdenummoxyoaenum blues pxues — |

3 MoO(OH)3 — 2 Mo03 + Mo(OH)3 + 3 H 20.

The formation of ilsemannite (Mo30 g “nH^O?) is related to this reaction. Ilsemannite occurs as a dark blue, earthy crust or stain at the Sierrita-Esperanza mine and several other molybdenum-rich porphyry copper deposits in Arizona. CHAPTER 3

MOLYBDENUM, TUNGSTEN, AND TITANIUM MINERALIZATION IN SOUTHERN ARIZONA

3.1 Area of Investigation

The area of this investigation extends from the .

Salt River of Arizona south to the border of the United . o o States and the Republic, of Mexico, and from .110 to 112 west longitude (Figure 6 ). It is bordered on the east by the Dos Cabezas and Chir.icahua Mountains, and on the west by the Ajo and Little Ago Mountains. There are seven

counties, or parts thereof, within this area: Santa Cruz,

Pima, Cochise, Maricopa, Pinal, Gila, and Graham. Twenty-

two mining districts with known porphyry copper-molybdenum mineralization also lie within this area (Table 14 and

Figure 6 ). Of these 22 districts, only 4 are producing

appreciable quantities of molybdenum at the present time:

(1) the Pima district (No. 5) on the eastern pediment

of the Sierrita Mountains,

(2) the Mammoth (San Manue1-Ka1amazoo) district (No.

14) 13 km northeast of Oracle,

, (3) the Mineral Creek (Ray) district (No. 15) on the

southwestern slope of the Dripping - Spring Mountains, and

49 50

YAVAPAI ) NAVAJO

GILA MARICOPA J APACHE \ .* PINTO . oA COPPER CITIES v z fVALLEY • I INSPIRATION^. z J

P. ! \ "21MIAMI / J SUPERIOR ♦ ' GRAHAM \ RAY 15 SACATON,0# O 12 \E320 I POSTON v CHRISTMAS BUTTE 13° A _ i s a f f o r d Ad FRANCISCO 17 GRANDE I k a l a m a z o o |4 0 #x COPPER CREEK ll8o VEK0L SAN MANUEL ------—L------19 AKESHORE__ ------0 16^MARBLE AC PEAK AJO SILVER BELL PIMA ! COCHISE

SANNAORTHa 5 | ♦'CAMP50 '" 2 A „ . E.B PIMA-MISSION-EISENHOWER 4 A qtw in BUTTES SIERRITA-ESPERANZA* 3 HELVETIA - ROSEMONT 1 | SANTA CRUZ j

N 0 7 RED MOUNTAIN 8 A MT. WASHINGTON A 0 DUQUESNE- * BISBEE f *------9— “ 'Wa s h in g t o n c a m p ------10 20 30 MILES J • • • .1 •• ■■ -I

25 50 KILOMETERS CANANEA

Figure 6 . Index map of porphyry copper deposits and re lated skarns in southern Arizona, as listed in Table 14.

o, porphyry deposit; □, related skarn deposit; 0 , contact pyrometasomatic deposit; A, promising district extensively explored. The shaded sym bols represent operating mines. 51

Table 14. Mining districts in southern Arizona with.known porphyry copper-molybdenum mineralization.

Pima County

1 a Ajo 2 Baboguivari 3 c Helvetia-Rosemont 4 Papago - 5 a Pima including;the Sierrita-Esperanza, Twin Buttes, Pima, Mission, Eisenhower, North San Xavier, and South San Xavier mines 6 a . Silver Bell y

Santa Cruz County •

7 c liars haw (Red Mountain) 8 Palmetto . • 9 c Patagonia (Mt. Washington)

. - . Pinal County - 1

10 a Blackwater (Sacaton Mountains). ; 11 b Bunker Hill (Copper Creek) 12 c Florence (Poston Butte) 13 c Francisco Grande 14 a • Mammoth (San.Manuel-Kalamasoo, Old Hat) 15 a Mineral Creek (Ray, Kelvin) 16 c Oracle (Marble Peak, Control, Santa Catalina) 17; Ripsey' (Tortilla Mountains) 1.8 c - Vekol 19 a Slate Mountains (lakeshore)

Gila County

. 20 a Banner (Christmas, Troy) 21 a Globe-Miami 'including the Inspiration, Mlami, Mi ami East, and Copper Cities mines 22 a Pinto Creek.. (Pinto Valley, Castle Dome)

a. Producing copper at the present time. b. Development work in progress. c. Extensively explored but not developed. 52

(4) the Globe-Miami district (No. 21) southeast of

Roosevelt Lake.

■ 3- • 2 Age Relationships

Most of the porphyry copper deposits in Arizona and

Sonora,were formed during the Laramide orogeny, 78 to 54

million years ago (Damon and Mauger, 1966? Livingston,

Mauger, and: Damony 1968; Livingston, 1973) . The Middle

Jurassic deposit at'Bisbee is a notable exception (Bryant

and . Metz., 1966) . . The Bisbee deposit is.also atypical,

because it lacks economically significant molybdenum .

mineralization. Some wulfenite was deposited on native

copper in the oxidized portions of the Campbell orebody,

but only traces of molybdenite have been found in the

Lavender pit.

There were two distinct periods of plutonic-

metallogenic activity in southern Arizona during the

Tertiary. The first period of plutonic and volcanic

activity was the Laramide orogeny. Appendix A lists the 40 40 Ar/ K ages of various mineralized Laramide intrusives

in the area of investigation. The. second.period of activity

occurred 35 to 18 m.y. ago, and coincides in time with the

deposition of molybdenite at Climax, Colorador and Questa, y

■ New Mexicoy The mid-Tertiary activity produced a belt of

plutons that extends from the Eldorado Mountains of Clark 53

County, Nevada, southeast.to the Chiricahua Mountains of

Cochise County. Some of. the Laramide copper and molybdenum may have been remobilized when this new belt was super imposed upon the preexisting Paleocene belt. Unfortunately, most of the mid-Tertiary ore deposits have not been dated. 40 40 The few Ar/ K ages available for southern Arizona are given in Appendix B. The histogram in Figure 7 summarizes ■ . the potassium-argon data for the copper-molybdenum-tungsten mineralization that has occurred since Early Cretaceous time.

The following;criteria were used to select the ages plotted in the:, histogram:

.(1) Only deposits that have been actively mined for hypogene copper, molybdenum, or tungsten.are included.

(2) All of the mineral deposits, are located within

Gila,.Pinal, Pima, Santa Cruz, Cochise, or Graham counties.

, (3) The mean age was used when. more than one intrusive ...- from a deposit was dated. • -

(4) A distinction is made between the classic pyrometasomatic deposit and the contact metasomatic deposit associated with an intrusive porphyry.

3-3 Types of Depo s it s

The Laramide intrusives creating the Arizona porphyry copper deposits have a number of petrologic characteristics in common. Stringham (1966) and others have found them to be primarily of granodiorite or quartz , iue . itga o KA dts o copper-molybdenum- for dates K-Ar of Histogram 7. Figure

Number of K-Ar Dates 10 -- 9 4 -- 4 - - 7 0 8 2 - - 3 6 5 I ------— - - --

y/- tungsten mineralization in southeastern Arizona. southeastern in mineralization tungsten 5 0 5 0 5 0 5 0 5 0 5 0 5 0 5 90 85 80 75 70 65 60 55 50 45 40 35 30 25 20 15 [ / f | SCHEELITE > CHALCOPYRITE > SCHEELITE | f / [ CHALCOPYRITE > WOLFRAMITE Q ORWOLFRAMITE SCHEELITE > MOLYBDENITE > CHALCOPYRITE | ? P CHALCOPYRITE > MOLYBDENITE > CHALCOPYRITE K-Ar Date (m.y.) K-Ar

54 55 monzonite composition,. In a few deposits (eQg. the

Sierrita-Esperanza orebody No. 5 ), biotite quartz diorite is also associated with the main porphyry phase„ Metalliza-. tion was preceded by successive periods of felsic intrusion.

In most instances, the porphyries were emplaced after the granitoid.rocks.. The unaltered granitoid intrusives can contain up to 3100 ppm of copper. The molybdenum content . is much smaller than that of the copper, and varies from

120 ppm to less than 3 ppm (Laine, 1974). These copper and molybdenum values are significantly higher than the■ \-.- average abundances of the two elements in granites, 10 ppm

Cu and 2 ppm Mo (Taylor, 1964). The Laramide granitoid intrusives also appear to be slightly more dioritic and richer in copper than those of mid-Tertiary age.

Although;the intrusives show many similarities, significant differences e^cist between occurrence char acteristics of individual deposits^ The•copper, molyb- . denum, and tungsten deposits of southern Arizona and northeastern Sonora can be divided into seven groups on the basis of form and geologic setting:

(1 ) the classic, disseminated porphyry copper deposits with alteration haloes and breccia zones inside a fractured stock, e.g., Ajo (No. 1) and Sah Manue1-Kalamazoo (No. 14);

' (2 ) breccia pipes in which sulfides fill interstices between propylitized rock fragments, e.g., the Ventura - 56 breccia pipe in. the Comoro Canyon granite (No. 8 ) and the

ChiIds-Aldwinkle pipe at Copper Creek (No. 11);

(3) the chalcopyrite, molybdenite, and scheelite-rich contact metasomatic deposits formed in the cupolas of the intrusive porphyries, e.g., Helvetia-Rosemont (No. 3) and

Twin Buttes (No. 5)?

(4) contact pyrometasomatic deposits, on the peripheries of stocks, in which chalcopyrite; and sphalerite are as sociated with disseminated scheelite or .molybdenite,, e.g. , v . ..

Johnson Camp and Duquesne-Washington Camp;

(5) simple quartz veins formed along fissures and shear zones within quartz monzonite or'granodiorite stocks, e.g.> the molybdenite-rich,•fluorite-bearing veins .with.relatively . coarse sericite on the Bronx property near Pinal Ranch '

(No. 22);

(6 ) quartz veins formed along faults., fissures, or shear zones in intruded country rock, e.g., the specularite- rich fissure veins in the Precambrian Oracle Granite of the

Tortilla Mountains at the abandoned Rare Metals mine

(No. 17); and

(7) sulfide-rich andesite dikes with quartz-sericite stringers following faults Or shear zones in granitic rocks, e.g., the;Las Guijas mine group. '

The ratios of wolframite, scheelite, and molybdenite to chalcopyrite vary widely among the seven types of - 57 deposits. However, two general observations can be made.

First, molybdenite is associated more often with scheelite than with wolframite. Second, wolframite can occur in trace amounts in the copper- and molybdenum-rich breccia pipes and quartz veins of the stocks (e.g., at the San Manuel mine), but is never found in skarn deposits (Groups 3 and

4). SCheelite, on the other hand, can form in all seven types of deposits,■and is commonly associated with wol^

framite, cha loopy rite,. sphalerite, or py rite. ': The calcium- v--- rich turigstate even occurs with native gold in quartz veins that are devoid of ohalcopyrite (e.g., the Reef mine in Carr Canyon). . .

Figure 8 shows 28 occurrences of tungsten minerali

zation in southeastern Arizona. - Most of them have been described by either Wilson (1941) or Dale, Stewart, and

McKinney (1960) . The'Characteristics-■of several deposits -

are summarized in Table 15. The present study .indicates.

that'more than -20% of ■ the. 28 occurrences are commercially ' .

exploitable if the price of tungsten concentrate remains

above $60 per stu WO^ (1967 dollars and a minimum of 65%

W03>v. V

3.4 The Spatial Distribution of Molybdenite and Scheelite , in Porphyry Copper Deposits and Related Skarns -

. ' Numerous authors have described, the different types

of alteration and alteration mineral assemblages found in r

YAVAPAI NAVAJO APACHE L._. ,X ------SPRING • CREEK------CAVE i PINE • CREEK •s MOUNTAIN r—--

MARICOPA • SILA r-s GREENLEE ------.X — i 12' PINAL T ' N RANCH \eS WESTLAKE 'SAMSELf \Z I GRAHAM PINAL 11 ^ SLACK HILLS AND SAN MANUEL MINE

• 10CAMPO BONITO 9 • ------1 MARBLE PIMA PEAK COCHISE * ASH GULCH I .DOS CA8EZAS JSOMOBA8I I 'TEXAS CANYON AND PIMA-MISSION JOHNSON CAMP . BABOQUIVARI 3 # 4HELVET1A-R0SEM0NT PARADISE TWIN" - * !• • BLACK PRINCE BUTJEsJWLs GUINDANI LAS GUIJAS.9 SANTA CRUZ CANYON .?AN.LU,S cPaR°V.DENC,A C ALA BAS AS* , e>6 i #7CARR CANYON MT. WASHINGTON*^ "WASHINGTON CAMP

20 30 MILES = b = d

23 50 KILOMETERS

Figure 8 . Some occurrences of tungsten mineralization in southeastern Arizona. Table 15. Selected tungsten occurrences in southeastern Arizona0

K-Ar Loca Age** tion* Occurrence Type (m.y.) Mineralization

1 San Juan Canyon claims, V6 28 - Scheelite-rich quartz veins in Quinlan Mountains, Pima gneiss, schist, and meta-arkose County.

■ 2 Las Guijas mine (aban 7 31 Wolframite, chalcopyrite, and doned) , Las Guijas Moun sphalerite-rich quartz veins that tains, Pima County. accompany andesite dikes within the Las Guijas alaskite

3a . Twin Buttes mine on the 3 :: 55 Disseminated chalcopyrite, molyb eastern edge of the denite, and scheelite in altered Sierrita Mountains, Paleozoic limestones and Cretaceous Pima County. arkoses %

3b Pima-Mission-Eisenhower 3 . 57 . Disseminated chalcopyrite, molyb orebody at the north denite, and scheelite in altered eastern end of the Paleozoic limestones and Cretaceous Sierrita Mountains, ■ arkoses • Pima County-

4 Helvetia and Rosemont . 3 57 Disseminated chalcopyrite, molyb Camp, Santa Rita Moun- denite, and scheelite in altered . tains, Pima County. Paleozoic limestones and the Cre taceous Bisbee Formation

Ul VO Table 15, continued« Selected tungsten occurrences in southeastern Arizona.

: . :f; :;v i:.' : :;i..v ': K-Ar ' - ■'] Loca- Age** tion* Occurrence Type (m.y„) Mineralization

5a Proto-Jackalo-Eaymaster . y 5 62 Chalcopyrite, sphalerite f. arseno- vein system, Proyidencia pyrite, and traces of wolframite in Canyon, Patagonia Moun- quartz veins that cut the Paleocene tains, Santa Cruz County. granpdiorite

5b Ventura breccia pipe, 2 62 Chalcopyrite, molybdenite, and Cox Gulch, Patagonia traces of wolframite in a breccia Mountains, Santa Cruz pipe that intrudes the Jurassic (?) County; Comoro Canyon Granite

6a Martha Washington claims, 5 60 Scheelite, chalcopyrite, and molyb- Italian Canyon, Patagonia : denite in qiiartz veins and fault Mountains, Santa Cruz gouge. The mineralization is pene- County. contemporaneous with shearing that . separates the granodiorite and quartz monzonite phases of the ■' . Paleocene batholith

6b Duquesne and Washington 4 62 Sphalerite, chalcopyrite, galena, Camp on the eastern edge" and traces of scheelite in al- of Mt. Washington, Pata- tered Paleozoic limestones gonia Mountains, Santa Cruz County.

7 Reef Mine, Carr Canyon, 6 48 Scheelite occurs in quartz veins Huachuca Mountains, along with traces of galena, stol- Cochise County. zife,and native gold. The quartz Table 15 , continued. Selected tungsten occurrences in southeastern Arizona.

V , : ' . K-Ar .;.V: ' . Loca- - . //..Age** tion* Occurrence , Type (m.y.) Mineralization

veins cut the middle Cambrian Bolsa Quartzite and the upper Cambrian Abrigo Limestone

8a • Texas Canyon, Little , 5. 52 Huebnerite, scheelite, sphalerite, Dtagoon Mountains, and minOr chalcopyrite occur in Cochise County. quartz veins that cut the Texas Canyon Quartz Monzonite

8b Johnson Camp, Little 4 52 Altered Paleozoic limestones con Dragoon Mountains, tain chalcopyrite, sphalerite, Cochise County. borhite, and minor amounts of molybdenite and scheelite .

9 Daily-Geesman mine group, 3 ? Chaldopyrite, bornite, and dissemi Marble Peak, Santa Catalina nated scheelite in altered Paleo Mountains, Pima County. zoic limestones

TO Campo Bonito mine group, 4 58-74 Microveinlets of scheelite in al Mogul Fault, Santa Catalina tered Paleozoic.sediments Mountains,' Pima County.

11 San Manuel mine. Black 1 65 Disseminated chaicppyrite and Hills, Pinal County. molybdenite in both the Predam- brian Oracle Quartz Monzonite and Laramide granodiorite porphyry. Some of the sulfide-rich quartz Table 15, continued. Selected tungsten occurrences in southeastern Arizona.

K-Ar Loca Age** tion* Occurrence Type (m. y.) Mineralization

veins also contain traces of wolframite

12 Clark prospect and Swede 5 58 Huebnerite and pyrite in quartz Vein, Pinal Ranch, north veins that cut the. Eocene of Highway 60/70, Pinal Schultze Granite (quartz monzonite) County.

*Re£er to Figure 6 .

**The ages of mineralization are based on data given in Appendices A and B.

to 63 porphyry copper deposits (e.g., Creasey, 1966; Fournier,

1967; Rose, 1970; Guilbert and Lowell, 1974; Gustafson and Hunt, 1975; Drummond and Godwin, 1976). For this rea son, the various chemical reactions involved in wall rock alteration will not be discussed here.

Meyer and Hemley (1967) identified five major, types of wall rock alteration produced by hydrothermal activity: (1 ) propylitic alteration, (2 ) intermediate . argilllc alteration, (3) sericitic alteration, (4) potas sium silicate alteration, and (5) advanced argillic altera tion. Guilbert and Lowell (1974) have developed a model of alteration zoning that incorporates many, of Meyer and

Hemley's concepts. - After studying the zoning relationships in the tilted, bisected and offset San Manuel—Kalamazoo orebody, Guilbert and Lowell concluded that a series of concentric alteration zones are formed within a stock whenever it develops cooling fractures and a hot brine circulation system.

Figure 9 is a schematic of the alteration zoning and associated mineralization present in a typical porphyry copper deposit. . The most intense alteration is observed in the potassic zone, where the primary silicates have been replaced by secondary orthoclase, biotite, and quartz.

The potassic alteration assemblage may also include sericite, calcite, anhydrite, fluorite, minor apatite,: and 64

PERIPHERAL VEINS OF CHALCOPYRITE, GALENA, AND SPHALERITE

PYRITE SHELL WITH 10% PYRITE, ORE SHELL 0.1 TO 3% CHALCOPYRITE, _ ? — ? WITH AND TRACES OF TO 3% CHALCOPYRITE, MOLYBDENITE PROPYLITIC ZONE 1% PYRITE, AND 0.03% MOLYBDENITE WITH 2 TO 6 % PYRITE

POTASS 1C m m ZONE

MAGNETITE SUBSTITUTES FOR PYRITE

Figure 9. Alteration zoning and associated mineralization in the center of the San Manuel/Kalamazoo por phyry copper deposit.

After Guilbert and Lowell, 1974. ■ 65

traces of rutile or scheelite. The bulk.of the chalco-

pyrite and molybdenite occurs in an ore shell that extends

from the outer part of the potassic zone to the inner part

of the phyllic zone. The. chalcopyrite-to-pyrite ratio in

the ore shell is generally 1:1, but can be as high as 3:1. .

The ore shell is surrounded in turn by a pyrite shell that

. fades otatward into the .pfopylitic zone.: The phyllic zone

and■the low copper core normally'contain only trace amounts:

of molybdenite.

Copper and molybdenum assays of core from two drill

holes at the Kalamazoo deposit (Chaffee, 197 6 ) support the

Lowell-.Guilbert model:.,. Assays • for gold and silver revealed . -

a previous metal anomaly roughly coincident with the copper-

molybdehum ore zone. The tungsten content of the core was

below the 100 ppm detection limit of the assay method.

Olade and Fletcher (1976) carried out similam trace element . :

studies at four porphyry * copper deposits in the Highland ■

Valley'Of British Columbia. .The Highland Valley data sug

gest that element ratios rather than single element values

should be used for exploration purposes. Olade and

Fletcher ■.also showed that, there were significant differences

between the trace element patterns of the Highland Valley -:

deposits and those at Kalamazoo.

Intense brecelation has tended to distort the Sym

metry of the alteration-mineralization zoning in some 66 districts. At Copper Creek, Copper Basin, and Cananea, much of the molybdenite is deposited in nearly vertical breccia pipes and irregular quartz offshoots that extend, outward from the central part of the stock. Each of the breccia pipes and offshoots has its own small alteration aureole.

In several of the copper-molybdenum deposits, only a small percentage of the ore actually occurs in the . quartz monzonite or granodiorite porphyries. At Ray, for example, most of the chalcopyrite is in the Younger Pre- cambrian.diabase sills and, to . a lesser extent , the Older

Precambrian Pinal Schist (Metz and Rose, 19 6 6 ). " The size - ■ and grade of the ore deposit in the country rock at Ray

apparently depend more upon the intensity of the fracturing

than upon the lithology of the invaded unit. A large part . of the molybdenite is disseminated along, the margins of the■

Granite Mountain Porphyry in the Pearl Handle pit where the

stock has intruded the Pinal Schist- The remainder of the . molybdenite occurs primarily as thin fracture fillings within the Precambrian quartzites and schist. Lesser

amounts of the sulfide are also present in quartz-

chalcopyrite-pyrite veins that cut the diabase. The Ray

deposit deviates from the Lowell-Guilbert model because

the center of the'alteration zoning does not coincide

with any of the Granite Mountain Porphyry stocks. More . 67

than three-fourths of the .porphyry lies, southwest of the

0rebody.and is. essentially barren. However, the deposit

does have concentric alteration zones, a low copper ©ore, an ore shell, and outer pyrite halo (Phillips, Gambell,

and Fountain, 1974).

Situations analogous to that at Ray exist in the

Pima, and Helvetia mining districts where porphyries have

intruded Paleozoic 'limestones and Cretaceous sediments.

A study by the author of the hypogene mineralization at ".

the ANAMAX.' Twin Buttes mine indicates that tungsten can be -.

recovered economically from several of the chalcopyrite-

rich, porphyry-related skarns. in southern Arizona. During. •

1976 and early 1977, mill head assays at the Twin Buttes mine averaged 11,000 ppm.copper, 430 ppm molybdenum, and

140. ppm tungsten. .The Mo/W ratio (by weight) of the feed

varied from 1.4 to 9.5.' In this deposit> copper > molyb

denum, and tungsten have been enriched, relative to their

crustal abundances, but the ratios of these abundances have

not changed significantly. Since the tungsten does not

occur as a sulfide, it appears that the copper-molybdenum-

tungsten enrichment mechanisms are independent of the amount

of sulfur in.the deposit. At least 95% of the hypogene

tungsten at Twin Buttes occurs as scheelite. The scheelite

contains 0.2 to 4.0 weight percent molybdenum, and is com-

monly associated with both chalcopyrite and molybdenite. 68

From 1964 to 1966, more than 2 x lo7 kg of rock

were sampled as part of the initial development of the Twin

Buttes orebody„ Some of the analyses of altered Paleozoic

limestones from the project are plotted in Figures 10 and

11. The chalcopyrite and molybdenite favor the: Paleozoic

limestones and siltstones^ but occur in all of the pre-

Tertiary rock types. • Most of the scheelite is distributed

.evenly between rock

data in Table 16. However, the distribution within any

rock type is somewhat erratic. Subecdnomic amounts of

scheelite are also present in quartz veins at the abandoned

Senator Morgan mine and other points on the periphery of ■ ■

the deposit.

3. 5 Rutile and Other Titanium-Bearing Minerals'Associated - with Chalcopyrite-Molybdenite Ores

. The titanium, content,of the.Laramide plutons,as- .

sociated with the porphyry copper deposits ranges from 1,100

to 5,900 ppm by weight, and depends partially on the ratio

of CaO to (KgO + Na^O). The average titanium content of

the unaltered quartz monzonites is about 2,700 ppm (Laine, .

1974) . . For comparison, NockOlds (1954) has reported an

average, world-wide value of 3,200 ppm for 108 biotite-rich

quartz:monzonites. Hydrothermal alteration can cause the

titanium to be redistributed within a pluton. However,

chemical analyses suggest that less than 25% of the total 69

cu 100 NUMBER OF SAMPLES =81 99

97,& •»» / • •*» •

2 3 4 5 6 7 8 9 MOLE PERCENT OF CU+MO + W

Figure 10. Normalized mole fractions of copper, molybdenum, and tungsten in altered Paleozoic limestones from the ANAMAX Twin Buttes mine, Pima County, Arizona.

Based on data from company records. 70

FE 100 NUMBER OF SAMPLES = 8I

/ #** /• • 9 0 /:/ /-:»

7 5 * CU 0 5 10 15 20 MOLE PERCENT OF FE +C U +ZN

Figure 11. Normalized mole fractions of iron, copper, and zinc in altered Paleozoic limestones from the ANAMAX Twin Buttes mine, Pima County, Arizona.

Based on data from company records. Table 16, Mill grade assays of sulfur and various transition metals in four rock types at the ANAMAX Twin Buttes mine, Sahuarita, Pima County, Arizona. - / ■ • ' 4 Compiled from company records. Each assay represents 2 x 10 to 15 x 104 kg of rock. . : ^

: ; 7 V:; ' S \,' / ( ./Ee- Cu Zn Mo W Rock Type (wt= %) (wt . %) (wt. %) (ppm) (ppm) (ppm)

Laramide quartz Mean of 10 0.87 2.0 0.31 300 . 230 100 monzonite porphyry Range 0.44 1.6 0,20 100 110 50 1.4 2.5 0.40 900 920 220

Mesozoic arkoses and Mean of 34 0.71 2,0 0.31 ■ 400 200 70 metavolcanics Range 0.22 0.99 0.09 100 80 8 1.4 3.8 0.73 1600 590 220

Paleozoic siltstones Mean of 6 2.3 5.5 1.0 800 540 120

Range 1.0 0.91 0.42 400 200 45 5.3 10.9 1.5 1400 1400 160

Altered Paleozoic Mean of 81 1.3 ' 6.1 _ 0.58 1000 240 130 limestones (garnet . or diopside) Range 0.37 1.8 . 0.23 100 70 40 9.8 12.3 1.2 3000 830 230 72 titanium is introduced.into the pluton by late-stage hydrothermal.: solutions'' (Smith, 1975? Laine, 1974; Davis, 1974;

Bauer et al., 1966; Creasey, 1965a).

Table 17 shows how titanium is distributed between the minerals of a typical granodiorite. At least half of the metal is tied up in ilmenite (FeTiO^) , sphene (CaTiSiO^), or rutile (TiO^). Most of the remaining titanium substi-

+3 +3 ■ tutes for Fe and Al : ions•in biotite and hornblende.

According to Deer, Howie, and Zussman (1962), primary biotites from calc-alkaline rocks can have from 1.7 to 5.4 weight percent TiO^« '. Titanium analyses of biotites from the Schultze Granite (quartz monzonite), the Cornelia

Quartz Monzonite, and the Patagonia Granodiorite all fell within this range (Graybeal, 1972). In porphyry copper , deposits, primary biotites•.apparently contain more titanium than do hydrothermal biotites. This phenomenon is docu mented by electron microprobe analyses of biotites from the Guichon batholith in the Highland Valley of British

Columbia. Reed and Jaitibor (1976) found that the primary biotites at the Highmont property have from 3.0 to 4 .6 weight percent TiO^, but that the hydrothermal biotites contain only 0.16 to 3.4 weight percent TiC^* The amount of titanium in primary amphiboles is usually less than that. in cogenetic, primary biotites (Graybeal> 1972) . At

Highmont, for example, the titanium content of the primary Table 17. Estimated distribution of titanium in the Ruby Star Granodiorite of the Pima mining district.

Ti Content Ti Content Percent of Wt.% of of Mineral of Rock Total Ti Mineral Rock* (wt.% TiQ2) (wt.% fi0 2) in the Rock

Plagioclase 48.6 ' 0.02 0.010 2 % Quartz , - 22 .7 0.002 V 0.0005 0 Microcline and orthoclase 18.9 0.01 0.002 0 Biotite and chlorite 5.6 4.0 0.22 39 Hornblende 2.0 1.0 . 0.02 4 Magnetite 1.1 0.02 0.0002 0 Ilmenite and hematite 0,4 0.26 o.io 18 Sphene 0.5 40.8 0.20 36 Apatite 0.2 0.00 o 0 Rutile 0.01 60.0 0.006 1 Zircon 0.01 0.09 0

100.0 0.57 wt.% 100% TiC>2 or 3,400 ppm Ti

*Estimated from modal analyses of Cooper (1960). 74 amphiboles ranges from 0.12 to 0,78 weight percent TiO-.

Like the biotites., the primary amphiboles .apparently con- . tain.more titanium than do their rare hydrothermal.counter parts.

Magnetite is an extremely common accessory mineral in the quartz monzonite and granodidrite stocks, and can accept up to 30 weight percent Tibg. Spinellids are also abundant in the skarns that border the stocks„ In the Pima and Cuprite mining districts, the titanium content of metasomatic magnetites is on the order of 0.02 weight-per cent TiO2 (Appendix F). At Twin Buttes the metasomatic:/ magnetite is associated with chaleopyrite and sphalerite . in serpentine-tremolite-actinolite zones.: Minor.amounts of hematite occur along the contact between the lime stones and the quartz monzonite porphyry.

Perovskite (CaTiOg), anatase (TiO^), and brookite

: (TiO2 ) are extremely rare in the porphyry copper environ ment. However, trace amounts of anatase and brookite have been found in the interstices between adularia crystals near the abandoned Santo Nino mine in the Patagonia Moun tains (Anthony et al., 1977).

Two types of rutile occur in the porphyry copper deposits. The first type is of magmatic origin, and is

found primarily in the unaltered phases Of the stock. The

second type is of hydrothermal origin, and is apparently 75 produced when primary, titanium-rich biotite and hornblende alter to chlorite. Some of the futile may also result

from the destruction of sphene (Williams and Cesbron,

1977). The hydrothermal rutile appears in all four altera tion zones, but occurs most often in the potassic zone, where it forms microscopic crystals along the edges of chalcopyrite-rich quartz veins.

Most of the -■ hydrothermal rutile can b e ' seen only

in thin section. However, black, acicular crystals up to

1 cm in length are intefgrown with the molybdenite and •

chalcopyrite.. at the Buena Vista mine in Providencia Canyon V on the western edge Of the PatagOnia Mountains. Two other varieties of macroscopic, hydrothermal rutile are found

5.3 km to the southwest at the Santo Nino mine on Mount

Washington, the highest peak in the- Patagonia Mountains.

One variety of rutile consists of tiny, reddish-brown

crystals less than 5 mm in length that are intergrown with

quartz, sericite, and clays. The second variety occurs

as 3 x 3 x 15 mm brown-red crystals in massive pods up to

10 cm in diameter. One of these pods is on display in the

University of Arizona Mineralogical Museum. Single crystal data on the rutile from the two Patagonia mines are pre

sented in Table 18.

Rutile in trace amounts has been identified in

specimens from most of the Arizona porphyry copper mines. Table 18. Unit cell parameters for. rutile* from chalcopyrite-molybdenite deposits in the Patagonia Mountains, Santa Cruz Gqunty, Arizona.

Alteration Cell Parameters in nm Deposit Assemblage c/a "" •: - co

Sample

PHK-9-67 Buena Vista mine Potassic . 0.649 0.459 ± .002 : 0.298 ± .005

PHK-4-69 Santo Nino, mine Phyllic 0.645 0.459 ± .002 0.296 ± .005

Literature Values

Schossberger (1942) 0.6438 0.4598 ± .0001 0.2960 ± .0003

Legrand and Delville (1953) 0.6442 0.4584 ± .0002 0.2953 ± .0001

Cromer and Herrington (1955) 0.64428 0.45929 ± .00005 0.29591 + .00003

Baur (1955) 0.6441 0.4594 ± .0003 0.2959 ± .0002

*Rutile is in the Tetragonal space group P4»/mnm. The Unit cell content, Z , is 2. ; - V j'"'/ :V ■■ ■■■ - 77

For example, Phillips, Cambell, and Fountain (.1974) . have reported finding hydrothermal rutile along the guartz- orthoclase-biotite veins that cut the quartzose Precambrian rocks at Ray. In another part of the pit, bright orange rutile is associated with secondary sphene in vein envelopes of altered diabase. Rutile (± sphene) also occurs in the propyiitic alteration zone at Pinto Valley, the phyllic alteration zone at both San Manuel and Morenci, and the quartz monzonite porphyry at Ago (Dixon, 1966). Mauger

(1966) has observed acicular rutile inside biotite phenocrysts of the Silver Beil Quartz Monzonite Porphyry. The biotite phenocrysts also contained inclusions of apatite,

zircon, and chalcopyrite.

The author has found a tungsten-rich variety of rutile intergrown with sericite, orthoClase, and quartz ;

.in the New Year*s Eve breccia pipe of the Esperanza pit.

Two spectrographic analyses of this tungsten-rich rutile

: (PHK-12— 72) are given in Appendix F. The cell parameters

in Table 19 were determined by indexing the powder pattern

obtained with a NorelCo diffractometer.

Hydrothermal rutile is important to the exploration

geologist because it is a useful prospecting guide for porphyry copper deposits (Williams and Cesbron, 1977).

The presence of stubby, black crystals of rutile in a matrix of sericite suggests relatively abundant chalcopyrite Table 19. Cell parameters for tungsten-rich rutile (PHK- 12-72), Esperanza pit, Sahuarita, Pima County, Arizona.

Reflection in nm Cell Parameter in nm

d„on = 0.1621 a . - 0.458 ± .001 220 o

d 01 = 0.1684 c = 0.295 . ± .001' 211 O

Synthetic rutile at 298 K, Swanson et al. (1969)

d 220 = 16237 aQ = 0.45933 ± .00001

doh r = 0.16874 c = 0.29592 ± .00001 ZJLJL O 79 and molybdenite mineralization. . The. rutile should be analyzed for both tungsten and copper, since the copper content of hydrothermal rutile from porphyry copper deposits normally ranges from 100 to 900 ppm (Williams and Cesbron,

1977, and this study). CHAPTER 4

CHEMICAL ANALYSES OF ORE MINERALS

4.1'.Preparation of Standards and Samples

The rutile and tungstate specimens, were identified from either their x-ray diffraction patterns or their . characteristic crystal.habits. Powdered crystal fragments of the minerals were analyzed with either a 114 mm Debye-

Scherrer camera (normal Straumanis setting) or a Norelco diffractometer fitted with a. vertical goniometer circle.

Nickel-filtered CuK-'series radiation was used in all of the

. * ■ - diffraction work. As discussed earlier, single crystal . measurements were made on rutile from two chalcopyrite- molybdehite deposits in the Patagonia Mountains using

Weissenberg moving film,techniques.

Chemical analyses Of molybdenite, wolframite, scheelite, rutile, and magnetite were carried out utilizing a variety of analytical techniques. One of the more sig nificant problems encountered was the lack of standards for these five minerals. At the beginning of the study, the,\ only minor element standard available in large quantities . was the National Bureau of Standards SRM-333 molybdenite concentrate from San Manuel. Spectrographic analyses of two splits of SRM-333 are shown in Table 20.= Table 21 lists

' 80 81 Table 20. Semiquantitative spectrographic analyses of NBS S.BM-r-333, molybdenite concentratef dated 14 March 1973.

Analyses were made by Hal W. JohnsonPacific Spectrochemical Laboratory, Inc. of Los Angeles, California. NBS values are 1.038% Cu, 0.087% . Re, and 93+% M0S2- ,

Split ' #1; #2 V. #1 #2

Mo . 52.5 wt.% 54.2 wt.% . mos2 87.6% 90.4% Cu 1.2 1.2 CuFeSq 3.5 : 3.5 Re nd < 0.07 tr <0.07 Res2 — . tr <0.09 Mg 0.030. . 0.024 MgO 0.050 0. 040, Al. 0.44 . 0.38 AI2O 3 V 0.83 0.72 Si V 3.4 1.8 Si02 7.3 3.9 C a . 0.069. 0, 050 CaO : .0.097 0 . 070 Ti 0.021 0.002 Ti02 0.035 ' •0.003 Fe 2.0 ' 1.8 FeS2 2.0 1.6

Total 101.4% 100.3%

B ' nd <0.007 K VI 0.30 V VI 0.004 Cr IV 0.002 Mn 11 0.003 Zn H 0,06 Ga IV 0 .05 Ge 11 0.01 Sr 11 0.01 Nb 11 0.08 Ru I« 0.02 Rh . f t 0.03 Ag 81. 0.0002 Sh II 0.01 ; Sb VI 0.03 Te II 0.10 Ta ; H . . 1.0 W II • 0.10 Pt : « 0.01 Pb n 0.08 Bi 11 0.002 U 11 0.30 82

Table 21. Semiguantitative spectrographic analysis of NBS SRM^154a, titanium dioxide.

Analyses were made by Hal. W. Johnson, Pacific Spectrochemical Laboratory, Inc. of Los Angeles, California. The NBS value i s •99.7% TiCu.

Ti 60. wt.% Ti02 100. %

Mg 0.0092 MgO 0.015 Al 0.033 AI2O3 0.062 Si 0.021 Si02 0.045 Ca 0.040 CaO 0.056

Total 100.3%

V nd < 0.03 Cr 11 0.003 Mn » 0.02 Fe 0.008 Cu 0.002 Y -■ 0.02 Zr 0.05 S n . 81 0.06 Sb 1! 0.08 W- 1* 0.40 Pb U 0.10 83 the elements found in the NBS titanium dioxide standard,

SRM-154a. In 1970 the Canada Centre for Mineral and Energy

Technology began preparing a suite of reference ores for

precious and base metal.analysis. This suite includes

PR-1 (molybdenum ore from the Preissac mine near Cadillac,

Quebec) and HV-1 (copper-molybdenum ore from the Highland

Valley of British Columbia). ;Inter-laboratory testing of many of the Canadian standards is still in progress.

In order to obtain calibration curves, it was neces

sary to prepare several series of Synthetic standards.

Quantities of analytical grade FeWO^ >. MnWO^, CaWO^, WS^,

and MoS2 were obtained from Cerac/Pure, Inc. of Milwaukee, Wisconsin. Differing amounts of these reagents were

weighed on a microbalance, and then placed inside poly

ethylene bottles on a roller mixer for three day periods.

Minor element standards were obtained by spiking these •

mixed powders with either transition metal oxides or the

transition metals themselves. Attempts were also made at

spiking these powders with a known volume of an aqueous

trace element solution and then drying the powder in a

vacuum oven. The mixed powder method was satisfactory for

many of the minor transition elements. However, the Na

tional Bureau of Standards glass wafer technique should be

used for analytical work below the 1000 ppm level.. The

liquid spiking method can give erratic results because 34 rhenium and several other transition metals vaporize in the oven at elevated temperatures.

Pure mineral separates-were obtained by either:

(1) crushing high-grade ore and then hand-picking the mineral under the microscope, or (2) by crushing kilogram quantities of low-grade ore to -65 + 150 mesh, and ex tracting the mineral with heavy liquid flotation and mag netic separation techniques. In.the second case, the crushed ore was washed after sieving and floated in acetylene tetrabromide. - The molybdenites and tungstates were removed in the sink and then resunk in either methylene iodide or thallium malonate-formate. A relatively pure sample of molybdenite can be obtained at this point by washing the concentrate in a beaker of distilled water and skimming off the molybdenite that floats to the surface of the water. .. The wolframite and scheelite were separated from one■another with a Frantz -ispdynamic magnetic separator.

One of the scheelite concentrates was roasted for 60 minutes at 820 K in order to convert troublesome pyrite to magne tite. The Frantz unit was also used in some cases to

separate the molybdenite from chalcopyrite and pyrite. If

sufficient sample is available, one can use these procedures

to obtain a mineral separate with a purity greater than 97%. 85 4.2 . Emission Spectrographic Analyses Portions, of the separates were ground to -200 mesh in a mullite mortar and submitted to the Pacific Spectro- chemical Co. of .Los Angeles for emission spectrographic analysis. Nylon screens were used to sieve the powder.

The mixed analytical-grade reagents described earlier were : sent along with the samples as corroborating standards.

The samples were analyzed with an Applied Research

Laboratories 1.5 m grating spectrograph. The spectrograph had a dispersion of 0.69 nm/mm, and a resolution of 0.035 nm with a 50 pm primary slit. .The controlled direct . current required for sample excitation was:supplied from an Applied Research Laboratories "Multisource” unit. Hal

W. Johnson used the following procedure to analyze more than 85 mineral separates for the author.

A 10 mg portion of each sample was weighed .on a microbalance and mixed with an equal amount of - spectrographically pure graphite. •This mixture was quantitatively transferred to the crater of a pre formed. graphite electrode. • The sample electrode and ■ a matching counter electrode were placed in the clips on the a r c - spark stand of the spectrograph and.spaced 9 ram apart with the center of the gap at the focal point of the instrument.

The samples were excited and completely consumed with a controlled D.C. arc at 13 amperes and 300 volts (short circuit). The light from the sample ex citation, attenuated'to give an exposure with suitable background, was integrated on Eastman Spectrum #3 photographic film. The film strips were processed afterwards in. an ARL. film developing, machine under controlled conditions. In order to ensure repro ducibility, considerable care was taken in preparing 86 and storing the processing solutions. The light re sponse of each emulsion lot- was also calibrated:prior to analysis, under identical conditions.

The densities of the spectral lines were measured with an ARL transmission densitometer. The transmis sion of the line and the background adjacent to the line were read in one sweep of the pickup head of the densitometer. Each, line was corrected for back ground using an emulsion-specific calibration curve, A line-to-background intensity ratio was then chi- V culated. The final concentration of each element was determined by multiplying these ratios by the . sensitivity factors for each spectral line. The sensitivity factors were calculated in turn from the line-to-background ratios of the standards,

The results of the emission spectrographic.analyses are - given in Appendices C through F,

. 4,3 X-^ray Fluorescence Analyses

Portions of some of these same mineral separates were analyzed using conventional x-ray fluorescence tech niques „ Again, splits were ground to -200 mesh. X-ray briquettes were prepared by: pressing the -200 mesh powder . into 25 mm diameter disks with a thickness of 8 mm. Each disk had a protective backing and rim formed from a 50:50 mixture of methyl cellulose and boric acid. The sample and binder were kept under a hydraulic press at 20,000 psi

(140 MPa) for approximately two minutes. One or - two drops of agar solution were mixed with the powdered mineral to keep the core together during the pre-pressing procedures.

Because of the large atomic numbers and high den sities of the samples, the critical thicknesses were 87 relatively thin (vo. 2 nun) in comparison to those required for silicate briquettes„ However, the large mean, atomic number of the matrix did.produce drastic, absorption effects in the analyses of the.low Z elements.

The briquettes were excited with bremsstrahlung and characteristic radiation from a molybdenum, tungsten, or chromium target mounted on a Siemens Kristalloflex 4

X-ray generator (65 KVP max. , 50 mA.- max. ) . Interferences from other elements were reduced by pulse-height discrimi nation. The x-ray techniques used to analyze the different tungstates are outlined in Table 22.'- The manganese cali bration curve for the wolframites is shown in Figure 12 to illustrate the tungsten absorption and iron enhancement effects. . The results of the x-ray fluorescence analyses -. are summarized in Appendix G. . Notice that the i r b n - t o - • manganese ratio in the wolframites from southeastern

Arizona can vary from 0 to 1.

• 4.4 Neutron Activation Analyses . Selected trace elements in molybdenite, wolframite,

scheelit.e, rutile, and magnetite were determined by in

strumental neutron activation. Chips, totaling 1.0 to

1200 mg, of each mineral specimen were carefully washed

in distilled water, dried, and weighed :into either h or

% ml polyethylene vials. The vials were then sealed with

a red-hot pyrex rod and encapsulated in a larger 8 ml Table 22. X-ray fluorescence techniques used in the analysis of wolframite and scheelite.

X-ray Ele Tube X-ray Analyzing 20 ment Target KVP mA Detector Crystal X-ray Line Position Vacuum

Mil* W 50 32 Nal(Tl) EdDT (020) . K alpha 1,2 27.63° Yes

Fe* W 50 44 Nal(Tl) LiF (220) K beta 1,3 76.16° No

Nb w - 55 46 NaL(Tl) . LiF (220) K alpha 1,2 30.44° No

Mo 50 6 Nal(Tl) LiF (220) L alpha 1 62.45° No

*In the case of scheelite, the generator settings should be increased to 55 KVP and 46 mA„ 88 • iue 2 Xry loecne airto cre sd odtrie h agns con manganese the determine to used curve calibration fluorescence X-ray 12. Figure Mn Kcc | 2 Lines p Corrected Net Counts (x 10^) Per Minute 20 4 0 W e F 0 vcae Chamber Evacuated dT 020) 0 2 (0 EdDT Target W 50 KVP, 32 mA 32 KVP, 50 tent of wolframites. of tent 2

6 egt ecn Manganese Percent Weight 8 10 12 14 16 nW04 0 Mn W VO 00 90 polyethylene vial along with a serial-numbered, 15 mg disk of analytical-grade copper. The doubly encapsulated vials were placed inside standard irradiation capsules and bom barded in either the "Lazy Susan" or the "Rabbit" of the

University of Arizona light-water cooled TRIGA reactor,

, The neutron flux in•the "Lazy■Susan" : is approxi- 12 2 mately 1.0 x 10 . neutrons/cm -s with the present core configuration at a power level of 100 kW. The flux for the "Rabbit" is a factor of 3 higher. The ."Lazy Susan" . was rotated, continuously during, each irradiation to obtain. a more uniform neutron fluence. The plastic-coated, copper disks were used to make corrections for minor variations y in the neutron flux.

After irradiation, the inner vials were placed on a plexiglas shelf above a Nuclear Diodes LGCC lithium- drifted germanium detector. The Operating bias voltage on the detector was maintained at + 2400 V. The detector had:a relative peak efficiency of 9.6% for the 1,3325 MeV 60 gamma-’ray of Co. The detector-preamplifier subsystem had a resolution of 1.98 keV (full width at half maximum) for the 1.3325 MeV gamma—ray. The peak-to-Compton ratio for that same gamma-ray was 34.5 to 1. A number of analyses were made after the detector was redrifted by the manu facturer. The operating bias on the redrifted detector ■ 91 was. lowered to +1600 V. The efficiency curve for the re drifted detector is shown in Figure 13„

The signal from the preamplifier of the Ge(Li) detector was amplified by a Canberra Model 1412 research amplifier> coupled with a Canberra Model 1468 live time corrector/pulse pile-up rejector, and then introduced into a .Northern.Scientific Model NS-623 8192 channel analog-to— digital converter (ADC) . The. ADC was operated with a 4096 channel Northern NS-636 series memory unit. ' Figure 14 is a . ■ ■ ■ # . ■ block diagram of the system. The pulse pile-up rejection circuits reduced data distortion and peak widening for samples with a high dead time (15 to 50%).

The multichannel pulse-height analyzer was inter faced with a Data General NOVA 1200 minicomputer. ,The . .

NOVA minicomputer was used to determine the area under each photoelectric peak, as well as the peak centroid, after subtracting the Compton background. The energy and resolution of each peak were also determined. Radda (1976) has described the NOVA software in detail. A Wang Model

10 magnetic tape transport system was used to store the spectral data of isotopes having half-lives less than 5 minutes., In the case of moderate or long-lived isotopes, the data were punched directly on paper tape with an ASR

33 teletype. ". The data on the punched paper tape were later Percent Efficiency at the Surface of the Detector iue 3 Te fiiny uv fr h ula Diodes Nuclear the for curve efficiency The 13. Figure lo.oo-r 0.50 0.50 — 5.00 — 2 LP - 1.046 - SLOPE The points represent the gamma-rays of "^^La "^^La of gamma-rays the represent L-982. points The detector germanium lithium-drifted LGCC and am Ry Energy Ray Gamma 37 Cs37 (KeV) 92 Punch Paper Tape

John Fluke Canberra ASR -33 415 B 1412 Teletype HVPS Spectroscopy I6QO Volts Amplifier 1

Cariberra Northern 1468 Northern Data General Canberra NS-623 Live Time NS-636 NS-440 Nova 1200 .970 100 MHz Corrector / Memory and Interface 16 K Preamplifier 8192 Channel Pulse Pile-Up CRT Display Minicomputer ADC Nuclear Rbjector : Diodes Ge(Li) Datum Detector for Matter Interfacen Wang Model 10 Magnetic Tape Transport

Figure 14,• Block diagram of the gamma-ray spectrometry system in the Department of Nuclear Engineering% University of Arizona. 94 transferred to punched cards at the University GDC CYBER

175 - DEC 10 computer complex.

Two FORTRAN IV programs: TOTO and PHIPLOT were used, to further analyze'the data. TOTO is a program written by George Kelson of the Nuclear Engineering Department.

It matches'- the measured energies of the gamma-ray peaks against those in an extensive library of known isotopes,

identifies each peak, and .then computes the part-per-million

concentration of each identified element. PHIPLOT uses -

the CDC CYBER 175 GOMPLOT system to plot and calibrate the

raw data in each channel,.thus bypassing the NOVA software.

The program helps detect gamma-ray interferences, electronic malfunctioning,. and pulse pile-up problems. \PHIPLOT is also useful for pulse-height stripping. CHAPTER' 5

DISCUSSION OF CHEMICAL ANALYSES

5.1 Minor Elements in Molybdenite

Significant amounts of magnesium, silicon, calcium, and iron were found in each of the 31 molybdenites analyzed \ with- the emission‘spectrograph. Aluminum, titanium, man ganese ,:and lead were also detected in more than one-fourth '

Of the samples. These spectrographic findings are sum marized in Table 23. One question, which immediately arises, is whether these eight elements are actually in-, . corporated into the molybdenite structure or form microscopic inclusions or intergrowths of some other mineral.

Only extensive examination of many different samples with an; electron microprobe can fully answer this question.

Nevertheless, several conclusions can be drawn from both preliminary scanning photographs taken by the author and microscopic observations of different molybdenite ores.

First, the bulk of the silicon is tied up in minute

inclusions of quartz and other common silicatesi For •

example, x-ray scanning photographs of a 80 um thick \ molybdenite flake from the•ANAMAX'Twin'Buttes mine showed

a 15 jim thick layer of calcium^magnesium aluminum silicate -

' ' 95 " . • 96 Table 23. Summary of emission spectrographic data for 31 molybdenites.

z Element Range in Weight Percent

12 Mg 0.0014 ———— 0.072%

13 . . A1 less than 0.004 -- — 1. 8 14 ■ Si 0.16 ——-— . 9.9 1 1 1 1 20 . Ca ' ' ' . less than 0.0004 w '■■y-

1 1 1 1

22 . Ti lessthan 0.002 o k ■ ■ 25 Mn lessthan.0.003 -- - - o o 22

26 Fe 0.046 .— —• 3 » 6 CO 1 1 29 Cu less than 0.0002 1 1 o H 1 1 1 1 38 : ■ : Sr less than 0.01 e

47 Ag less than 0.0002 • _____ o „ 0058

82 Pb less than 0.08 0.45 97 sandwiched along a (0001) cleavage plane in the sulfide.

However, no significant amount of silicon was detected in

the coinciding 'molybdenum and sulfur-rich parts of the

flake. A number of 1.0 to 500 ym thick lenses of quartz,

sericite, and chlorite, were observed sandwiched between

leaves of molybdenite from the Bagdad pit, the Santa Ana-

Buena Vista mine, and the Tae Hwa mine. . Several 20 um ellipsoids and 10 x 250 um stringers of quartz were also

found in 2•mm diameter flakes of molybdenite from the Santo

Nino mine, . • •'

Second, the bulk of the iron is due to inclusions

and intergrowths of either chalcopyrite or pyrite. Numerous examples can be cited. Abundant molybdenite-chaIcopyrite

intergrowths can be seen in the pink, altered granodiorite

of the Santo Nino mine. ■ Several 250 um wide inclusions . o f .chalcopyrite, barely visible to the naked eye, were found

inside 3 cm wide molybdenite books from the Tae Hwa mine.

Although most of the iron is in inclusions, some actually

occurs in the molybdenite itself. Scanning photographs of

the previously described flake from Twin Buttes revealed

that small amounts of iron, aluminum, and tungsten are . .

distributed uniformly thrQUghoui: the sulfide.

Third, only part of the calcium occurs as inclusions

of calcite, anhydrite, and calc-silicates. Most of the

remaining calcium is present either in the molybdenite . . . 98 itself, or as fine, interleaf coatings, of gypsum that were

deposited on the sulfide by percolating mine waters. Ca

K-alpha scanning photographs of three different' molybdenite

grains from Twin-Buttes showed calcium uniformly distributed

throughout the. molybdenum and sulfur-rich areas. The

association of calcium with the molybdenum may indicate that the molybdenite has started to alter to powellite.

5.-2 . Rhenium, Selenium, and Other Trace Elements in Molybdenite

Twelve other elements - were found in trace amounts

in the molybdenites: B, V, Cr, Cu, Zn, Se, Sr, Ru, Ag,

W, Re , and Bi. , Lyakhovich and Sandomirskiy (1974) and

other investigators have detected.nine additional elements

in the mineral; G a ,, Ge , A s , Sn, Sb, Te, Os, Pt, and 'Tl.

.The presence of V, Cr , Cu, Zn, Se, Sb, W,. Re, Os, Tl, and

Bi in molybdenite from the Esperanza pit (PHK-12-72) was.

confirmed by Henn Oona and Peter Kresan, University of -

Arizona (personal communication, 1977), using proton-excited

x-ray analysis. The Esperanza sample also contained signifi

cant amounts of Ti and Fe along with trace Sc, Mn, Ni, and

Hg. Most of the copper occurs with the iron in trace chalco-

pyrite. The strontium, on • the other hand; is substituting

for calcium in the trace Calcite, anhydrite, and calc-

silicates. The. samples with the highest strontium values

also had the highest calcium values. 99 • According to. Karamyan (1962) , Mogarovskii (1963) ,

and Filimonova (1972) part-per-million amounts, of both

selenium and tellurium substitute for the sulfur in molyb

denite. The 107 samples analyzed by Karamyan from the

Kadzharan copper-molybdenum deposit in Soviet Armenia had

average concentrations of 430 ppm Re, 335 ppm Se, and 33

■ ppm Te* For comparison, the selenium analyses of some of

the molybdenites in the present study are shown in Table 24.

Rhenium was not discovered until 1925, when Walter

Noddack, Ida Tacke Noddack, and 0. Berg detected it in

; molybdenite, osmiridium, and- various pegmatite minerals

(Noddack and Noddack, 1931). The minerals richest.in

rhenium include:

chalcocite, Cu^S

bornite,. CUgFeS^.

chalcopyrite, CuFeS^

tetrahedrite, Cu^Sk^S^g

tennantite, Cux2As4S13 wuifenite, PbMoO^

columbite, (Fe,Mn)(Nb,Ta) .

tantalite, (Fe>Mn)(Ta,Nb)

gadolinite, BegFeYgSigO^Q thortveite, (Sc,Y)SigO^ '

zircon, ZrSiO^ 100 Table 24. Selenium and other trace elements in molyb denite.

Analyses were made by.the■staff of the Rocky Mountain Geochemical Corp. of Tucson, Arizona. The selenium was determined by extracting yellow diphenylpiazselenol into toluene, and then mea suring the optical density of the organic solu tion at 420 nm with a colorimeter. The other five elements were all determined by atomic ab sorption spectrometry. -

Concentration (ppm)

Deposit ■ Se - Co Ni . Cd . Pb . Bi- ->: PHK-09-67 71 20 25 5 255 40 Buena Vista 86 15 50 5 190 50

PHK-llb-69 .i • : 84 20 30 : 8 60 50 Santo Nino ■

PHK-23-69 165 85 : 125 25 790 165 El Tiro "

PHK-2Ob-71 ■ 96 ' 15 ; 25 .. 9 120 ■■■ 65 Childs- Aldwinkle

PHK-12c-72 . 79 _ 15 30 10. 30 70 Esperanza 90 . 25 20 7 60 .... 80

PHK-41-75 - . 217 . : 15 V:.; 30 . 6 240 65 Helvetia •:

PHK-38b-76 171 20 20 8 25 45 Twin Buttes 215 15 105 7 45 45 192 . 10 35 6 40 45

TB-6-77 102 ' 15 40 8 235 45 Twin Buttes - : 105 20 40 12 215 40 Concentrate

PHK-28-69 ' 61 35 55 9 135 55 Chungking

PHK-14-75 96 20 : ■ 55 . 21 535 1100 Tae Hwa 101 Table- 24, continued

Concentration (ppm) Deposit •____ Se . Co Ni Cd . - Pb_____ Bi

NBS SRM-33 175 15 45 9 90 35 San Manuel 185 15 50 35 90 25 Concentrate

Cerac A.R. 31 20 65 7 225. 40 Molybdenum. Disulfide

Sample Description: PHK-09-67 Rosettes in a chalcopyrite-rich quartz vein, Buena Vista mine, Providencia Canyon, Pata- . gonia Mountains, Santa Cruz County, Arizona.

PHK-llb-69 . - Disseminated flakes in altered granodiorite, ■ Santo Nino mine, Mt. Washington, Patagonia „ Mountains,/Santa Cruz Couhtiy, Arizona. /

PHK-23-69 Quartz veinlets in tactite, El Tiro pit, Silver Bell mine, Pima County, Arizona.

PHK-20b-71 Rosettes in quartz-cemented grariodiOrite brec cia, main haulage level, Childs-Aldwinkle mine, Copper Creek, Galiuro Mountains, Pinal County, Arizona. PHK-12c-72 Pods in the New Year's Eve breccia pipe, 3760 ft level, Esperanza pit> Sahuarita, Pima County, Arizona. .

PHK-41-75 Disseminated rosettes and blebs in garnetite, main dumps near the Mohawk shaft, Helvetia, - Santa Rita Mountains, Pima County, Arizona.

PHK-38b-76 Disseminated flakes and blebs in garnetite, center of the East pit, ANAMAX Twin Buttes . mine, Sahuarita, Pima County, Arizona. .

TB-6-77 Reconcentrated concentrate, ANAMAX Twin Buttes mine, Sahuarita, Pima County, Arizona. 102 Table 24, continued

PHK-28-69 Book, 3 cm in diameter, unidentified locality, Chungking district, Szechwan Province,' People's Republic of China.

PHK-14-75 Book, 4x4x3 cm, Tae Hwa mine, Nungam-ni, Ch*ungch'ong-Pukto Province, South Korea. Aminoff (1943) found that molybdenite from the coba.lt-

arsenic-nickel ores of Lainijaure, .northern Sweden, con

tained as much as 2500 ppm Re. Riley (1967) determined

the rhenium content of 41 Australian molybdenites by spiking 185 a solution of the fused sulfide with ,Re, separating the perrhenate anion from the molybdate anion with a pyridine

solution, and then measuring.the rhenium 185/187 ratio on

a mass, spectrometer. ■■ ■ The rhenium in the 41 samples ranged -

from 0.25 to 1690 ppm. Trace amounts of rhenium have also

been detected in at least 35. other minerals by Badalov .

et al. (1967) and other investigators. '

Samadi, Ailloud,.and Fedoroff (1975) were able to

_Q detect 1.5 x 10 . g of rhenium in molybdenum by bombarding .

the metal'.with: .thermal, neutrons for 20' minutes in a flux %

of 4 x.10 12: neutrons/cm 2-s. The key nuclear reaction is:

'L^ R e (n,y) ^88Re. 188Re has a half-life of 16. 8 hours and

an intense gamma-ray at 155 keV. The radioactive metal was dissolved in aqua regia and titrated with 7 M NaOH.

The rhenium and technetium were then extracted from the 18 alkaline solution with--acetone. The 8 Re was separated

from the more intense 8^mTc on an anion exchange column

with an ammonium thioCyanate elutant.

The author also used the 155 keV gamma-ray to

determine /.the rhenium content of. molybdenites, but ir- :

radiated the samples for only 4.0 minutes in a flux of 104 12 2 1.0 x 10 neutrons/cm -s. Because of the higher rhenium concentration in the molybdenites, the author did not feel it was necessary to use the radiochemical separation pro cedure developed, by Samadi et al. (1975).

The tungsten in the molybdenites was determined at the same time as the rhenium. The amount of spurious 187 Re formed by the interaction of neutrons with the 187 daughter' W is negligible:

1^W(n,y)1^W — — 1^ R e ( n fY)1^Re. /4 /4 Th = 23.9 hours /b /b

1 R 7 The principal gamma-rays of W have energies of 134.24,

479.48, 685.70, and 772.84 keV. The 685 keV peak was used in the calculations instead of the 479 keV peak because 18 8 Re has an interfering gamma-ray at 478 keV. Counting 101 was delayed for one hour to allow the Mo. (T% = 14.6 minutes) , the \"®>mRe (T% =: 18.6 minutes) , and "*"^^"Tc (T^ =

14.0 minutes) to decay away. The instrumental neutron activation results are presented in Table 25. Figures 15 * and 16 are gamma-ray spectra of two typical molybdenite samples. : The spectra were obtained less than 24 hours after the irradiation.

Manganese was found in several of the irradiated molybdenite samples. One of these samples was collected from the El Tiro pit of the Silver Bell mine in Pima 105

Table 25. Thermal neutron activation analyses of molyb denites .

Mo (%) Re (ppm) W (ppm) Deposit Flake 181.06 keV 155.00 keV 685.70 keV

PHK-09-67 #1 59.23 ; 32.4 51.3 Buena Vista ' #2 67.01 33.4 48.0 63.21 31.9 55.1 ; 64.49

. #3 60.59 31.7

Mean 62.913.1 32.410.8 51.513.6

PHK-07-69 ■ : #1 : 56.71 9.63 31.5 Santa•Ana • #2 60.08 8.62 29.7 Mean 58.412.3 ■ 9.110.7 . 30.611.3

PHK-llb-69 #1 . . 64.98 511.5 11.6 Santo Nino #2 .. 61.80 476.6 9.26 Mean 63.412.3 ' 494 125: 10.411.7

PHK-23-69 : . #1 59.51 1209.7 10.1 ' El Tiro ' 60.18 1140.5 — — ' Mean 59.910.5 1175 149

PHK-38-69 ;' #lz 51.02 113.2 61.3 Pinal Ranch #iy 59.07 132.7 40.3 PHK-20b-71 #1 64.93 784.3 30.2 Childs- : Aldwinkle ■ ■ #2 - 65.79 788.6 32.7 63.77 735.8 67.85 --

#3 65.97 ' 606.6 1.33.1

Mean■, 65.711.5 729 185 65 159 106

Table 25, continued. . Activation analyses of molybdenites.

Mo (%) Re (ppm) W (ppm) Deposit Flake .181.06 keV 155.00 keV 6 85.70 keV

PHK-12c-72 #1 58.62 108.2 97.1 Esperanza #2 62.36 154.5 352.0

# 5. 60.47 148.9 357.2 60178. .

#4 60 . 81 150.4 353.5 62.19 138.1 396.1 #5 64. 25 151.9 409.6

#6 65.52 142.1

Mean. 61.9 ±2.2 142 ±16 328 ±115

RED-57-66 #1 58.64 215.1 40.1 Nacozari .

UAKA 74-184 #1 64.01 . 27.8 126.1 Mina . 67.67 12.5 158, 0

las Higue'ias 64.86 .

61. 83 35.2 140.5

UAKA 74-184 #1A 61.37 26.5 140.6 Mina las.Higueras #2A 58.26 27.5 .143.3 Mean 63.0 ±3.2 25.9±8.3 142 ±11

PHK-28-69: #1 57.46• 31.3 , 122.5 : Chungking

PHK-11-75 #1 63.60 4.93 109.1 Tae Hwa 107

Table 25, continued. Activation analyses of molybdenites.

Mo (%) Re (ppm). W (ppm) Deposit Flake 181.06 keV 15.5.00 keV 685.70 keV

NBS SRM-333 ■ #1 59.90 17.3 San Manuel concentrate #2 57.08 16.2 63.42 — 60.53

#3 57.72 ' 16.5

' #4 57.66 13.6

#5 . 55.00 7 15.8 ,

' #6 61.26 13.5 Mean 59.1 ±2.7 / 870. 15.5+1.6

Sample Description

PHK-09-67 Rosettes in a chalcopyrite-rich quartz vein, ; Buena Vista mine, Providencia Canyon, Pata gonia Mountains, Santa Cruz'County, Arizona.

PHK-07-69 Rosettes in altered quartz monzonite, Buena Vista mine , near Santa Ana and Santa Rosa , ^ Sonora.

PHK-llb-69 Disseminated flakes in altered granodiorite, Santo Nino mine, Mt.. Washington, Patagonia Mountains, Santa Cruz County, Arizona.

PHK-23-69 Quartz veinlets in tactite> El Tiro pit. Silver Bell mine, Pima County, Arizona.

PHK-38-69 Greisenized quartz vein in the Schultze Granite (quartz monzonite), Bronx mine, Pinal Ranch, Pinal-Gila county line, Arizona.

PHK-20b-71 Rosettes in quartz-cemented granodiorite breccia, main haulage level, Childs-Aldwinkle mine, Copper Creek, Galiuro Mountains, Pinal County, Arizona. 10 8

Table 25, continued« .Activation analyses of molybdenites.

PHK-12c-72 Pods in the New Year's. Eve breccia pipe, 3760 ft level, Esperanza pit, Sahuarita, Pima Countyy Arizona.

PED-57-66 Rosettes in a chalcopyrite-rich pegmatite, Mina la Guadalupe, Nacozari de Garcia, Sonora.

UAKA 74-184 Disseminated flakes in altered granodiorite, 7 Mina.las. Higueras, Pericos, Sinaloa.

PHK-28-69 Book, 3 cm in diameter, unidentified lo cality, Chungking district, Szechwan Province, People's Republic of China. .

PHK-11-75 ■ Twinned book, 2 cm in diameter, Tae Hwa mine, C h 'ungch1ong-Pukto Province, South Korea. Figure 15. Gamma-ray spectrum of molybdenite (PHK-12c~72) from the New Year's Year's New the from (PHK-12c~72) molybdenite of spectrum Gamma-ray 15. Figure

Log of Gross Counts per Second (x ICf2) . 0 0.4 0.36 0.44 .4 -- 0.24 0.20 0.32 -- 0.52 .8 -- 0.28 0.56 .8 - 0.48 breccia pipe, 3760 ft bench, Esperanza pit, Sahuarita, Pima County County Pima Sahuarita, pit, Esperanza bench, ft 3760 Arizona. pipe, breccia 54 ad e X-rays Re and W 70 86 102 nry in keV Energy 118 3 150 134 4.1"m 140.51 " 142.63 m 9 9 155.0 8 , , I I89,_, 8.6 Mo 181.06 166 99 182

Eve 109 Figure 16. Gamma-ray spectrum revealing the presence of trace tungsten in molyb in tungsten trace of presence the revealing spectrum Gamma-ray 16. Figure

Gross Counts per Sec. 0.2 00 4 0 8 0 6 0 2 2 1.0 1.2

8484 8 4 68 4 0 2 4 78 . 0 1 8 64 7 9 4 R e 8 , e 7 W > Arizona. denite (PHK-12c-72) from the Esperanza pit, Sahuarita, Pima County, County, Pima Sahuarita, pit, Esperanza the from (PHK-12c-72) denite 0 0 6 t5IIOOe4Cu 5 1 1 . 7 0 , B r W + 616

,528999Mo 848 5 5 1 . 7 0 l 8 , W 664 Energy In keV In Energy 668 684 685.70 W 700 716 739.7 Mo 732 748 770 Mo 2 764 700 . 11.1 County. The gamma-ray spectrum of this molybdenite is shown

in Figure 17. It is. not known whether the .manganese- is

actually, substituting in the structure for molybdenum,

or whether the manganese is in minute inclusions of a min

eral like alabandite (MnS). The manganese could even be

in thin oxide films along the (0001) cleavage planes of the

molybdenite. Giles and Schilling (1972) analyzed molybdenites

from various environments using a colorimetric technique.

The - rhenium-bearing molybdenite was fused with•potassium

pyrosulfate, dissolved, and concentrated on finely pul

verized activated carbon. The absorbed rhenium was then? .-

leached from the carbon with NaOH and extracted as

tetraphenyl-arsohium perrhenate. -.This last step separates

the-rhenium from the accompanying vanadium, chromium,

molybdenum, and tungsten.' The rhenium was then complexed

with thiocyanate and analyzed by colorimetry. Minczewski

and Foldzinska (1967) have also had success in separating

rhenium from tungsten by forming a perrhenate complex with

methylene blue and precipitating the rhenium a*s with

- thioacetamide.

Giles and Schilling (1972) found that molybdenites

from the classic porphyry copper deposits'contained sig- ' ni.ficant.ly. more rhenium than ' those • from copper-poor molyb

denum deposits: (91-2840 "ppm with x ^q = 720 ppm) vs. Figure 17. Gamma-ray spectrum of molybdenite (PHK-23-69) from the El Tiro pit, Tiro El the from (PHK-23-69) molybdenite of spectrum Gamma-ray 17. Figure Log of Gross Counts per Second (x I0‘3) 0.00 50 .5 0 2 1.00 1.50

00 998

1001.66182 Ta 1001.66182 1010 ivr elmn, iaCut, Arizona. County, Pima mine, Bell Silver ^n lohs hrceitc htpas t 812 n 21. keV. 2112.6 and 1811.2 at photopeaks characteristic has also “^Mn 1030 1 0 44.40 ,82Ta 44.40 0 1 1050 nry n keV in Energy 1070 092 59 1099.27 1090 1113.18 182 -iTa 1110 1121.19— 182 105 Sc 1120.5 1130

1160 112 113 (7-129 ppm with = 53 ppm)„ The molybdenites from

greisens, pegmatites, and skarns had.rhenium contents in

the same range as those from.the porphyry molybdenum de-

posits. - The molybdenites from Ray (9 Samples)f San Manuel

(2), Silver Bell (2), and Castle Dome (3) analyzed by the

two investigators fell in the 300 to 2000 ppm range. The

samples which they obtained from Esperanza had values

ranging from 90 to 200 ppm.

. . The data obtained by the author support the findings

of Giles and Schilling (1972) . The rhenium values, for molybdenite from the New Year1s Eve breccia pipe fell." within their range for the Esperanza deposit. Samples from

Copper Creek, Silver Bell, and San Manuel all contained more than 600 ppm rhenium. The rhenium contents of molyb

denites from isolated veins, like that at the Buena Vista .

mine, were at least an order of magnitude smaller.

Badalov, Basitova, and Godunova (1962) used a

colorimetric technique similar to that of Giles and

Schilling (1972) to analyze molybdenites from Central Asia.

Several of the Central Asian molybdenites were associated

with either wolframite or scheelite. The three Russian

investigators suggested that rhenium-rich molybdenite

provinces exist throughout the world, and that.the rhenium

variation within a province is controlled by the temperature

of deposition of the molybdenite. They proposed that the 114 rhenium content increases as the temperature of deposition decreases,, but that the mean content of the rhenium in the deposit depends upon the characteristics of the province.

As an example, they cited the copper—molybdenum province of Soviet Armenia where the rhenium values are abnormally high in every type of deposit. ■ Both the present study and that of Giles and Schilling indicate that southeastern

Arizona and northeastern Sonora also constitute a high rhenium province.

5.3 Minor Elements.in. Wolframite .

Magnesium and silicon were found in each of the 22 wolframites analyzed With the spectrograph. Much of, the silicon occurs as microscopic inclusions of quartz. As an example, stringers of huebnerite from the Little Fanny ■ claims in Sheep Basin contained 1 urn-wide inclusions and numerous intergrowths of vein quartz. Thin films of sericite were also observed coating huebnerite crystals from the neighboring Hawk claims and several other deposits.

Some of the specimens from the Panasqueira district in

Portugal had extensive intergrowths of arsenopyrite as well as quartz and muscovite. The huebnerite from the

Adams mine in Colorado (PHK-31-76) had a very high silicon value because the sheaves of thin, tungstate blades were cemented together by micrometer-thick incrustations of tiny quartz crystals. 115 The magnesium is apparently substituting on a limited, basis: for the ferrous cation. Aluminum and calcium were also present in more than four-fifths of the samples

(Table 26). Part of the calcium is tied up in trace

fluorite and small intergrowths of scheelite, while the

rest substitutes for the manganous cation,

. 5.4 Scandium,. Niobium, and Other Trace Elements in Wolframite ^

., Twelve additional elements were detected in the wolframites.ScyTi/CUr Zn> Y, N b , Mo,:Ag, Sn, Ce, Yb,

and Ta. All of the rare earths are present in trace .

amountsy:but many of them will have to be determined

radiochemically using, specialized neutron, or proton activa

tion techniques,

R. J. Meyer (1908) showed that appreciable amounts

of scandium are present in East. German wolframites. Ac

cording to Borisenko (1963), the Sc^O^ content of wolframite

from pneumatolytic hydrothermal deposits seldom exceeds

0.40%, The wet chemical and spectroscopic analyses of some

wolframites from the classic tin-tungsten-uranium deposits

of the Erzgebirge are presented in Table 27. Scandium was

detected in. all but one of the Erzgebirge samples (Leutwein,

1951).

Ganeev and Sechina (1960) analyzed wolframites from

quartz-feldspar veins and greisens in the. Kara-Oba granites 116

Table 26. Summary of emission spectrographi.c data for 22 wolframites.

Z Element ■ Range in Weight Percent

12 Mg 0. 012 — ■— 2.2 %

13 A1 less than 0 „ 005 —— --; 0.25

14 Si 0.019 -- - 13.0

20 Ca : less than 0.0004 — — 1.5 :-

21 Sc less than 0 . 0 0.1 ———— 0.079

22 Ti 0.00 36 ———— 0.051 .

29 Cu lessthan0.0004 --- 0.093

30 Zn less than 0.03 . T -- 0.13

39 ' Y less than 0.002 .--- 0.0055

41 ■ Mb ■■■ ' less than 0=03 ———— 0 . 36

42'; ' MO less. than : 0. 00 8 «• 0.038

47 Ag less than 0 . 0008 —— 0.0092

50 Sn less than 0.009 --- 0.059

58 Ce less than 0 . 0 4 : . —-"T- 0.12

70 Yb less than 0. 004 —— — 0.032

73 Ta less than 0 .' 20 . ---- 0.50 117 Table 27. Wet chemical and spectroscopic'analyses of wolframites from the Erzgebirge and neighboring mining districts in Saxony and Bohemia. From Leutwein, 1951.

■ ■ i

in in m m m m CO O O m CN O m O O o O O CN CN ro o o O CN (N O O (N O CN CN CN CN CN O o 0) nj id IN • -H O CN P 5h P

Deposit B Cm n u § EH CO Total . cn 3 £ o ; H id O CO 1 Zinnwald 74.45 9.56, 11.38 2.35 0.87 0.75 0.74 0.36 100.46 0.28 0.09 0.20 0.10 , 0.040 0.02 0.005 0.002 0.1 1 Schlaggenwald 73.05 13.60 11.50 0.10 0.30 0.77 0.12 0.58 100.02 0.3 0.02 0.1 0.08 [ 0 - 050 0.03 , 0.009 0.003 . 0.01 Kupfergrube Sadisdorf 73.22 15.30 9.88 0.21 0.41 0.43 0.52 0.50 . 100.47 0.3 0.05 0.08 0.05 | 0.030 0.01 0.008 0.003 ' 0.1

Stangengrun 74.14 ,19.50 5.48 0.17 0.31 0.25 0.23 0.12 100.20 0.07 0.001 0.05 0.03 | . 0.010 0.003 — 0.004 0.002

Luise Brunndobra • 74.05 19.35 4.95 . 0.18 0.10 0.05 0.09 1.26 100.03 -- — 0.005 o.oo: ——— 0.001 0.05

Altenberg 72.30 19.80 4.70 0.71 — — 0.67 2.39 100.57 0.15 0.05 0.20 0.15 | 0.100 0.05 0.008 0.005 0.01 1 Gottesberg 74.30 20.20 4.18 0.35 — — — 0.29 0.93 100.25 0.05 0.09 0.08 O'. 03 | 0.010 0.005 0.001 0.005 --

Zschorlau 72.75 18.80 3. 88 0.01 0.18 0.16 0.12 4.05 99.95 0.08 0.01 0.02 0.02 o.dio 0.003 — 0.002

Pechtelsgrun 75.58 21.46 1.67 0.78 0.30 0.15 0.10 — 100.04 0.10 . 0.02 0.04 0.03] 0.Q20 0.004 — 0.005 0.001

i 118 of central Kazakhstan, and .found eight trace, elements, in

the tungstate: Si, C a , Sc, Ti, Y , N b , Mo, and Sn. The principal ore minerals in the Kara-Oba veins are molyb denite , cassiterite, bismuthinite, galena, sphalerite,

and pyrite. Fluorite and topaz are also associated with

some of the muscovite. Leaching experiments and micro

scopic studies' later showed that the wolframites contained ... minute inclusions' of sphene, rutile, zircon, . cassiterite, .: and quartz. However, the scandium and yttrium appeared to be substituting in the crystal for the iron and man- : ganese. Nothing could be said about the role of niobium during the crystallization of the wolframites.

Ganeev and Sechina (1960) also found that the iron- rich wolframites were enriched in scandium and depleted

in yttrium,:while the manganese-rich wolframites were .

depleted in scandium and enriched in yttrium. This same

phenomenon was observed by the author in all of the wol

framites, regardless of age, from southeastern Arizona.

The ferberifes from the San Manuel mine and Ventura

breccia pipe contained more than 300 ppm scandium, while

the huebnerites from Texas Canyon had less than 25 ppm.

Plots of the scandium content as a function of the Fe/Mn

ratio have been the subject of considerable controversy.

Borisenko and Komissarova (1961) believe that there is -y

no direct relation between the scandium and bivalent iron 119 in a wolframite crystal. They have proposed instead that the scandium content increases with increasing deposi

tions! temperature and pressure,.

Goldschmidt and Peters (1931) suggested that the

presence of scandium, niobium, and tantalum in wolframites was the result of the following isomorphous substitution mechanism:.

Sc+^ + (Nb,Ta)+^ displace (Fe,Mn)+^ +

More recent work indicates that this Mechanism applies to

only a fraction of the total niobium and tantalum.

Barabanov (1971) and Fronde1 (1968) have proposed a second

mechanism that involves aluminum:

' (Sc,Al,Fe)+3 +(Nb,Ta)+5 displace (Fe,Mn)+2 + W +6.

However,Ganeev and Sechina (1960) showed that scandium .

and yttrium substitute respectively for iron and man

ganese. A third mechanism must then be considered:

2 Sc+3 displaces 3 Fe+^ and 2 Y+3 displaces 3 Mn+3.

There is considerable disagreement in the literature

about the applicability of these three mechanisms. '

Leutwein (1951) observed that wolframite samples from

,Altenberg and Gottesberg in the Erzgebirge contained

scandium, but no niobium or tantalum. In addition, a 120 s.ample from .nearby Luise Brunndobra contained niobium

and tantalum, but no scandium (Table 27). Further work

by Borisenko (1963) supported Leutwein's findings. Of

234 wolframite samples from the USSR.that contained scandium, 59 did not have any detectable niobium. • Sixty- nine, other samples contained up to 0.3% 1^ 20^, but no

scandium.

Zuyev et al. (1966) examined wolframites from a

Siberian greisenized granite with an electron microprobe

and discovered microinclusions of tantalo-niobates; in thev .

individual tungstate grains. Three detailed microprobe \

studies by Distler (1967), Chetyrobotskaya (1967), and

Ivoylov et al. (1973) have proved conclusively that microinclusions of columbite-tantalife group minerals do indeed

occur in wolframite crystals.. In addition, Ivoylov and .

his colleagues have shown that some of the niobium and

tantalum occurs outside of the inclusions either as uni-

formly..dispersed inclusions less than 1 ym in size or as an isomorphous admixture.

None of the three substitution mechanisms can be

ruled out at the present time.

5.5 Minor and Trace Elements in Scheelite

Thirteen minor and trace elements were detected

in the eight scheelites analyzed with the.spectrograph: 121 Mg, A l ,. Si, Ti, Mn, Fe, Cu, Sir, Y, Mo, Ce, Y b , and Pb

(Table 28). The presence of strontium in scheelite from both the Huachuca and the Little Dragoon Mountains was

confirmed by x-ray fluorescence. Electron microprobe

mounts were made of chalcopyrite-molybdenite-rich garnetite

from the West pit at Twin Buttes„ One of the garnetite

.specimens (AMAX 1009) contained 1 cm crystals of scheelite.

associated with both pyrite and molybdenite. Scanning

photographs of AMAX 1009 revealed that minor acounts of

molybdenum were homogenously distributed throughout both

the scheelite and the pyrite. Quantitative x-ray micro- ' • probe analyses of nine scheelite grains from Twin Buttes

are given in Table 29. The molybdenum content of the

scheelite grains ranged from 0.01 to 12.69 weight percent.

Scandium and tantalum were determined in both

scheelite and wolframite by neutron activation analysis.

Figure 18 shows the characteristic scandium, iron, and

tantalum photoelectric peaks.produced by an irradiated

ferberite chip from the San Manuel mine. The scandium

analyses are presented in Table 30. The scandium content

of the scheelite is at least one order of magnitude smaller

than that of the cogenetic wolframites. It appears that

the rare earths do not follow scandium. Cerium and the

other rare earths are more abundant in the scheelites than

in the cogenetic wolframites. 122 Table 28. Summary of emission spectrographic data for eight scheelites..

z . Element • Range in Weight. Percent

12 Mg 0.0052 — :—— 0.12 %

13 ■ . A1 less than 0.008 -- - 0 .15 1 1 1 1

14 Si 0.017 tv)

22 - - Ti ': less than 0.002 -- 0 o 014

25 Mn 0.0045 --- - 0 e 0 89 i i i 1 w m 26 ■ Ee - ; less than 0.005 . o

29 Cu 'less than 0.0003 -- - 0.039

38 , Sr ■ ■ 0.003 0 . 3 5 1 1 1 I H 39 ' Y less than 0.002 a: o W

42 Mo 0. 02 ■— "•' 3 o 8

58 Ce less than 0.04 -— — G o 075

70 Yb less than 0.004 G o 048 r- CN 1 1 82 Pb less than 0.10 1 1 Table 29. Electron microprobe analyses of molybdian scheelite from Twin Buttes.

Analyses were made by T. Teska, M. Rauschkolb,and P. Kuck.

RMG-13-77 PHK-16-77 - , v . Sulfide '/• Quartz Vein TB-lA-77 Tailings at the Theoretical Gravity Concentrate of Sulfide Tailings from the Senator Values for from the ANAMAX Mine ANAMAX Mine Morgan Mine Scheelite V3J. di ll 2 1 2 wt.% 1A IB ■ ■ 2 ■■ ■’: 3 ;-v4 5 1 0* 24.17 22.93 21.46 24. 83 24.74 22.18 21.80 20.81 20.99 20.82 22.23 s 0.17 0.18 0.18 0.45 0.00 0.17 0.13 0.Q6 . 0.09 0.07 0.00 Ca 13.92 13.89 14.21 15.45 12.18 * 14.03 13.93 14.12 13.97 13.65 13.92 Fe 0.01 0.00 P.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Mo 3.53 3.64 3.54 12 . 69 0.01 3.07 2.02 0.02 0.58 0.40 0.00 w 58.20 59.36 60,41 46.5,8. 62,94 60.55 62.12 64.99 64.37 65.06 63.85 Pb 0 . 0 0 0.00 0.19 0.00 0.13 0.00 0.00 0.00 0.00 0.00 0.00

CaO 19.48 19.43 19-88 21.62 17.04 19.63 19.49 19.76 19.55 19.10 19.48 WO 3 73.39 74.86 76.18 58.74 79.37 76.36 78.34 81.96 81.18 02 . 05 80.52 PbO 0.00 0.00 0.20 0.00 0.14 0.00 0.00 0.00 0.00 0.00 - M0O3 4 . 94 5.06 4.94 18.03 0.02 4.23 2.74 0.00 0.68 0.45 - MoS2 0.40 0.45 0.42 1.12 0.00 0.42 0.32 0.03 0.22 0.17 - FeS?** 0.02 0.00 0.02 0.00 0.00 0.00 0 . 0 0 0.00 0.00 0.00 — SOj 0.00 0.00 0 . 0 0 0.00 0 . 0 0 0.00 0.00 0.12 0.00 0.00 - 98.23 99.80 101.64 99.51 96.57 100.64 100.89 101.99 101.63 101.77 100.00

*The oxygen value is assumed to equal the difference between 100% and the sum of the values for the other six elements.

**A11 of the iron is assumed to be in minute inclusions of pyrite. 123 iue 8 Aprino te am-a setu fr raitd ebrt (PHK-2-69) ferberite irradiated for spectrum gamma-ray the of portion A 18„ Figure Log oi Gross Counts per Second (x 10"3) 0.00 0 .5 0 2.00 I .00 1.50 998

01612Ia I 1001.66102 0 01030 1010 eod cpa a peet t 8. keV. 889.3 at present was peak Sc second A rm h SnMne mn, ia Cut, Arizona. County, Pinal mine, Manuel San the from 46 1044.40 182 Ta 1044.40 1050 nry n keV in Energy 001150 1070 092 59 1099.27 1090 3.18 182 Ta i 1110 u— 1121.19 182 Ta 105 6 Sc 46 1120.5

1130 124 125 Table 30. Scandium content of wolframites and scheelites.

Sc Content (ppm) Deposit Chip 889.25 keV Peak

PHK-04-68 ■■ ' ' less than 0.9 Scheelite less than 0.5 Daily mine

PHR-l7a-72 less than 0.9 Scheelite less than 0.5 . Kaneuchi mine

PHK-02-69 #1 548. Ferberite 556. San Manuel mine 560.

. #2 ': 561. , 570.

#3 . 53 6.

PHK-30-69 #1 • : : 484.: Ferberite 481. Ventura breccia pipe #2 434. .

#3 ^ 182. . 201.

PHK-39-69 : 45.9 Huebnerite• 42.7 Clark prospect 44.9

PHK-06-71 #1 ' 3.78 Huebnerite 3.90 Little Fanny claims 4.73

' #2 ; 4.93 00 PHK-11-72 : #1 Wolframite ' Jackalo mine 42 5.51

PHK-17-72 6.95 Wolframite . 7.61 Kaneuchi mine 126 Table 30, continued

Sample Description:

PHK-04-68 3 x 1 mm blebs of white scheelite disseminated in a matrix of garnet, epidote, calcite, and chalcopyrite. Daily-Geesman mine, near Marble Peak, Santa Catalina Mountains, Pima County, . Arizona.

PHK-02-69 Black ferberite crystals with pyrite in crystalline quartz. Pegraatitic vein in mon- " zonite porphyry 1475 ft level of the San Manuel mine, Pinal County, Arizona. Col lected by Dr6 Willard C. Lacy. PHK-30-69 Brown wolframite pod in a vuggy quartz zone of a chalcopyrite-molybdenite-rich breccia . pipe. Ventura breccia pipe, Cox Gulch, Patagonia Mountains,. Santa Cruz County, Arizona.

PHK-39-69 .Huebnerite and pyrite crystals in a quartz- orthoclase vein, Clark prospect, northeast of Pinal Ranch, Pinal County, Arizona.

PHK-06-71 'Huebnerite: from a quartz vein that also con tains minor galena,\ chalcopyrite, sphalerite, . and coveilite. Little Panny claims. Sheep Basin, Little Dragoon Mountains, Cochise County, Arizona.:

PHK-11-72 Wolframite crystals in vuggy quartz with traces of pyrite and galena. Chalcopyrite, arsenopyrite, and sphalerite occur in other samples of vein quartz * Jackalo mine, north fork of Providencia Canyon, Patagonia Moun tains , Santa Cruz County, Arizona.

PHK-17-72 . 6 x 3 x 0.5 cm black wolframite crystals in milky quartz. The quartz also contains minor scheelite and chalcopyrite. Kaneuchi mine, 'Kinki District, Kyoto Prefecture>■Japan. 127 5.6 Tungsten, Copper, and Other Trace Elements in Rutile

At least 18 minor and trace elements, occur in the

rutile associated with the copper-molybdenum ores : Mg',

Al, Si, Ca, Sc, V, Cr, Mn, Fe, Cu, Y, Zr, Nb, Sn, Sb, Ta,

W, and Pb.. . Spectrographic data for five rutiles are sum

marized in Table 31. A typical gamma-ray spectrum from

. one of the irradiated rutile samples is shown in Figure 19.

Both the neutron activation and the spectrographic data

indicate that tungsten substitutes more readily for titanium .

in rutile than for molybdenum in oogenetic molybdenites.

Using a laser probe., Williams and Cesbron (1966)

found that rutiles from porphyry copper deposits contain

significantly more copper than do rutiles of other origins

(100 to 500 ppm vs. 1 to 50 ppm) . The two also observed

that the (Cr-t-V) / (Nb+Ta) ratio of the porphyry rutiles is

unusually high. • The author's limited number of spectro-•

graphic analyses tend to support both of these observations.

Antimony is present in several varieties of rutile.

Rutile from pegmatitic veins and schists at the Big Bell

gold mine, Cooatdy, Western Australia is known to contain

up to 5.8% WO^f 1.7% SbgOg, and 1.7% FeO by weight (Graham

and Morris, 1973). The author also found significant

amounts of antimony in black rutile (C-l) from the Champion

Sillimanite mine of Mono County, California. 128 Table 31, Suirjmary of emission spectrographic data for . five rutlies, .

Tantalum is also present, but is not reported : because of its' poor detectability.

z Element Range in Weight Percent CM O O 1 1 12 Mg 0.0021 1 1

13 A1 0.087 —— 0 o 17

14 Si 0.32 ——-— 1*9 i i i I K> 20 Ca 0.0047 o

21 Sc less than 0.0010 0.0044 23 • V 0 . 065 — — 0.19 1 1 1 1

24 Cr 0.024 O H

25 Mn less than 0.02 •. ———— 0 o 070 . I i i i w 26 V Fe - 0.31 00

29 Cu less. than 0.0008 — — - 0o 083

39 Y less than 0.02 0,12

40 less than 0.05 — —— 0.61

41 Kb 0.074 — — 0.16 i i i I K) 50 Sn less than 0.03 o 1 1 I

51 Sb less than 0.08 O 00 1 i 1 to 74 , W / less than 0.50 u>

82 Pb less than 0.10 --- - 0 e 46 o — 0 .4 0 889-346 Sc 1120.546 Sc 891.9182 To 11 21.19182 To

« 0 .3 0 II20.4214 Bi CZ)

0.20 959.II182 To O 911.2 Ac bkgd 964.4 8Ac bkgd. v) 010 I22I.3I182 To 968.8Z2eAc bkgd II 88.95 To III3.I8I82To I230.93'82 To O 0 .0 5 1001.eG'"-1 To 1157.4 r To JJ 0 00 +-+ > I l-H | I I I \H-H \ I /f-t-H | t~H-j-H-t |-f H-|-f t-h| t M | I M | > \~\ f\ 673 883 9 05 921 9 3 7 953 9 6 9 985 1001 1105 1121 1137 1153 1169 1185 1201 1217 1233 Energy in keV

Figure 19. Gamma-ray spectrum of rutile (PHK-4-69) from the Santo Nino mine on Mt. Washington, Patagonia Mountains, Santa Cruz County, Arizona. 129 CHAPTER 6

TRANSPORT AND DEPOSITION OF MOLYBDENUM AND TUNGSTEN

6.1 Transport Problems

The transport of heavy metals is one of the keys to understanding the origins of the Arizona porphyry copper de posits. Somehow, large quantities of molybdenum and tung

sten have been transported through the crust for at least one kilometer, and then deposited in the late-stage quartz v veins■associated with the.Tertiary Stocks Pods of solid molybdenite weighing more than 10 kg each .have been found

at the:Santo. Nino mine. One of these pods is on display in

the University of Arizona Mineralogica1 Museum. Even heavier blocks of huebnerite■have been brought out o f .the ' Texas

Canyon and Las Guijas mines (Henry G. Worsley, personal .

communication, 1976). A block of nearly pure huebnerite

from the Bluebird (Primos) mine, northwest of Texas Canyon

Summit, reportedly weighed 1 Mg (Cooper and Silver, 1964).

There are several possible transport mechanisms for

the two heavy metals:

(1) Micrometer-size grains of molybdenite and other

sulfides could be rafted on the surface of hydrothermal

waters at temperatures less than 425 K. A rafting mechanism

130 131 could account for the molybdenite selvages commonly observed along the edges, of the quartz veins, ■ The rafting of tungstenite is less feasible because of the mineral's greater density.

(2) Acidic, hydrothermal solutions carrying partially polymerized MoO^ .and WO^- anions could be introduced into, iron- and calcium-rich rocks where precipitation would occur.

Part of the sulfur could have been already present in the . ... country rock, or introduced, as H^S. before ,the- appearance of.the heavy metals. The formation of complex halide ions may help increase the solubilities of the two heavy metals

(Helgeson, 1969; Crerar and Barnes, 1976).

, (3) Tremendous amounts of NaCltrich:,. meteoric water could have circulated through the cOoling, fractured stock ' over hundreds of years„ thfortunately, fluid circulation mechanisms and their accompanying rock alteration reactions are not well understood . (Norton, 1978). It has been hy pothesized that the meteoric water carried part-per-billion quantities of copper, molybdenum, tungsten, and other

transition metals from the surrounding rock and continuously deposited them in the fractured zones of the stock (White,

1968) . Deposition would take place at points where the

temperature of the solution reached a maximum, or the pH became moderately alkaline. 132 If present interpretations of fluid inclusions are correct, many copper-molyhdenum ores have been formed by saline fluids in the temperature-pressure region above the critical point of pure water (647 K and 218 atmospheres)'.

A hydrothermal solution at a depth of only 2 km would have a lithostatic pressure of about 500 atmospheres exerted, upon it. Gas-phase transport does not appear to be a feasible mechanism Under these conditions for several reasons:

(1) The temperatures involved are less than 875 K.

Below 875 K,. the vapor pressures of MoQ^ and WOg-H^O are too low to allow formation of■the observed ores (Krauskopf,

1967) . .

(2) The halides and oxyhalides of the two heavy metals rapidly hydrolyze at temperatures above 335 K. ;

(3) The copper-molybdenum-rich skarn zones along the borders of the Baramide stocks are too extensive to have been formed by magmatic gases. ; .

6.2 The Solubility of Different Molybdenum and . Tungsten Minerals in Hydrothermal Brines

The molybdates and tungstates of Calcium, manganese

(II), and iron (IT) are only slightly soluble in:water.at

298 K and 1 atmosphere pressure.. Zelikman and Prdsenkova ...

(1961) have determined the solubilities of FeMoO^. and other normal transition element molybdates. Their solubility - 133 measurements are combined in Table 32 with.those, of other

investigators„ In order to resolve the inconsistencies in

the solubility data for CaMoO^, Zhidikova and Malinin

(1972) made measurements on synthetic powellite in aqueous

NaCl over a temperature range of 323 to 573 K. Their data

are presented in Table 33. From the data, one sees that an.

increase in temperature has little effect on the solubility

of powellite. .

FeMoO^, MnMoO^, and FeWO^ are all extremely soluble

in cold, concentrated hydrochloric acid. However, the

author was unable to dissolve MnWO^ in hydrochloric acid

without first heating it. Table 34 is a crude solubility

chart drawn up by the author for some of the more common

molybdenum and tungsten compounds. Notice■that:even at 373 ;

K these compounds resist dissolution by certain acids and ..

alkalies. For example, molybdenum disulfide and tungsten

disulfide are only slightly soluble in hot, concentrated . .

hydrochloric acid, but can be readily dissolved in a 50:50

mixture of concentrated HNOg and H 2SO4.

6.3 Depositional Temperatures

In the past, some investigators thought that the

mineral assemblage was uniquely indicative of the deposi- .

tional temperature of the tungsten ores. Table 35 shows a '

genetic classification of tungsten deposits based on this

assumption. However, Naumov and Ivanova (1971) made Table 32. Solubilities of the normal molybdates in water at selected temperatures.

The values marked with an asterisk are extremely controversial. nd in dicates that measurements were not made at that temperature.

Solubility in Grams of Solute per ; 100 Grams of Saturated Solution

Compound . 298 K 323 K 373 K Reference

Li2Mo04 44.81 43.50 42.4.9 RoSenheim and Reglin (1921)

Na2Mo04 39.40 41.18 45.47 Funk (1900) and Cadbury (1945)

64.57 65.27 Ricci and Loprest (1953) K2Mo°4 66.96 Rb2Mo04 68.00 nd nd Spitsyn and Kuleshov (1951)

Spitsyn and Kuleshov (1951) Cs 2Mo04 67.18 nd nd

MgMo04 15.89 18.40, 8.48 Ricci and Linke (1951)

CaMo04 0.0058* 0.0056* 0.0177* Spitsyn and Savich (1952) 0.013 nd 0.0167 Zelikrnan and Prosenkova (1961)

SrMo04 0.0104* nd nd Smith and Bradbury (1891) 0.0216 nd nd Rao (1954)

BaMo04 0.0058 nd nd Smith and Bradbury (1891) 0.0055 nd nd Rao (1954) 134 Table 32, continued

Solubility in Grams of Solute per 100 Grams of Saturated Solution

Compound 298 K 323 K 373 K Reference

0.00386 0.00637 nd Ricci and Linke (1951) A92Mo04 ;

FeMoO^. 0.0076 nd 0.036 Zelikman and Prosenkova (1961)

CuMoO^ 0.038 nd 0.38 Zelikman and Prosenkova (1961)

ZnMoO^ 0.37 nd 0.46 Zelikman and Prosenkova (1961)

CdMop4 0.0067 nd nd Zelikman and Prosenkova (1961)

PbMo04 : 0.000012* nd nd Muldrow and Hepler (1958) 0.03 Zelikman and Prosenkova (1961)

For Comparison:

Ma2W04 42.38 44.58 49.31 Funk (1900) 135 Table 33. Solubility of CaMoO^ in NaCl solutions of various concentrations.

After Zhidikova and Malinin, 1972.

Equilibrium Concentration of CaMoC>4 in Solution (grams per 100 grams of NaCl solution)

Molality Temperature, K of NaCl Solution 348 . . 373. . ' 423 , :: 473 523 573

0.001 0.00280 0.00188 0.00312 0.00126 0.00062 - 0.02 , — —- 0.06272 0.00292 0.00156 0.00146 0.05 0.00460 . 0.00334 0.00196 0.00146 -- - 0.17 0.0048 — — : - 0.20 -- - 0.00528 0.00528 0.00316 0.00212 0•00168 0.34 0.00766 ■ ■— 0.50 0.01010 0.00858 0.00902 0.0060 0.00322 0.00322 0. 86 0.01160 -- 1.0 0.01082 0.01014 0.00688 . 0.00596 0.00640 1.19 0.0136 1.53 0.01682 —— " 1.89 0.02014 -- , -" — — --- 2.00 . 0.01396 0.01164 0.00840 0.00954 2,22 0.02356 - 137 Table 34. A crude.solubility chart In the temperature range from 298 to 371 K for molybdenite and selected tungsten compounds.

The solutions were observed over a 2.5 day period. No significant differences in solubility were observed when the solutions were heated at 371 K for one hour.

Upper Limit for Solubility in Grams of Solute per 100 Liters of Solution

CaW04 MnW04 FeW04 ws2 .■. MoS2 : :

Distilled water 30 15 20 5 20 1. 00 M NaOH. . : .15 / IS9 - . 10 20 ■ 30f

1.00 M NaCl 30 15 . 10 10 - 5 0.10 M FeCl- < • 609, 35a ' 15 a , sa lO3 - , d o O H

6 M HC1 30b ■ 5b 109 10 10 10.0 M HC1 a . 60 40° 10 30 1 . 0 i% h2sg-4 10b: 35b :- ■ 25g,b 15 . 5 i.o : 20b /.- 5C ;-; ' 5 : 2 M ^ 4 : e:

a. The. iron formed a brownish-white precipitate upon heating. .

b. The compound reacted with the solution and . formed a bright canary-yellow cake. The yellow cake is presumed to be a hydrate of tungstic acid..

c. This value is very close to the true solubility.

d. The compound completely dissolved. The solu bility is greater than 45 g/100 1. e. The compound completely dissolved. The solu bility is greater than. 15 g/100- 1.

f. The sulfide coalesced.

g. The compound reacted with the solution and formed a dull greyish-brown cake. Table 35. A genetic ..classification of tungsten deposits based on the assumption that the mineral assemblage is indicative of the temperature of deposi- ::: tion. ' ' Adapted from Li and Wang, 1955.

Zone and Estimated Temperature o f . Formation Type of Mineralization

Epithermal Either blanket deposits in calcare Tungsten-rich iron and 325 - 475 K ous tufa, or veins and fissure fil manganese oxides deposited lings in sediments. Typical min in blankets and fissures erals include tungsten-rich ps H o by Pleistocene hot springs me lane , hollandite, and limonite in at Golconda, Humboldt a gangue of jarosite, quartz Seri- County, Nevada. cite, barite, calcite, and dolomite. Huebnerite, scheelite, and adularia can occur at

Me so thermal ■ 475 - 575 K Ferberite, scheelite, adularia, and Brecciated veins of "horn" calcite in chalcedonic quartz veins quartz and quartz mon- ■ cutting felsic plutons and gneisses, zonite Cemented by fer- Minor minerals include barite, chal- berite at Nederland, copyrite, pyrite, sphalerite, and . Boulder County, Colorado, galena. ' : '

Hypothermal Wolframite, cassiterite, and pyr- Cordillera Real, Llallagua, 575 - 775 K rhotite in quartz veins that tran- . and Potosi tin mines of sect both batholiths and bordering Bolivia. altered sedimentary rocks. Other minerals include arsenopyrite, chalcopyrite, pyrite, sphalerite .. and bismuthinite. . ' Table 35, continued

Zone and Estimated Temperature of , Formation Type of Mineralization Examples

Pyrometasomatic Disseminated scheelite and sulfides Scheelite deposits of the 775 - 1075 K : in skarns of garnet, diopside, and Cottonwood-American Fork epidote. Minor gangue minerals in mining district, Utah. clude forsterite, tremolite, wol- lastonite, and calcite.

Orthotectic Wolframite.and cassiterite-rich Quartz veins in biotite 850 - 1275 K pegmatites, quartz pegmatitic granite at the Mawchi and veins, and greisen bands. Other Hermyingyi mines of the minerals include tourmaline, Shan-Tenasserim belt, scheelite, molybdenite, arseno- Burma. pyrite, pyrite, chalcopyrite, muscovite,:fluorite, and 139 .140 . theririobarometrie studies of fluid inclusions in wolframite, cas.site.rite, quartz, fluorite, beryl, and stibnite from

several different types of tungsten deposits, and were able to estimate the pressure and temperature of the mineralizing

solutions„ Naumov and Ivanov had to use both the decrepita tion and homogenization methods to obtain reliable evidence on the depositional conditions. The two investigators con cluded that wolframite i s ■formed at temperatures ranging

from 520 to 720 K and pressures ranging from 550 to 1650 atmospheres. Moreover, the bulk of the wolframite deposits . , are formed in the•narrow temperature range of 550 to 620 K.

The stibnite associated with many of the wolframite ores is deposited after the wolframite at much lower temperatures .

(350 to 470 K). The mineral assemblage is apparently not

indicative of the depositional temperature« The pressures were estimated from the CC^ content of the inclusions. > .

Carbon dioxide apparently plays an important role in the hydrothermal transport of the transition elements.

Kelly and Turneaure (1970) have used similar tech

niques to determine depositional temperature ranges for

the Bolivian tin-tungsten ores. The early-stage cassiterite- wolframite-scheelite-rich veins formed at temperatures

between 570 and 800 K„ The pyrrhotite and most of the other

base-metal sulfides were deposited later when the 141 temperature dropped from 670 to 530 K„ Pressures in.this

situation may havebeen as low as 200 atmospheres.

Sillitoe and Sawkins-(1971) examined a variety Of

fluid inclusions in quartz crystals from copper-bearing

tourmaline breccia pipes in Chile. They concluded that the

quartz in the pipes was deposited over a temperature range

of 620 to 710 K, and that the pipes were formed 2 to 3 km below the early Tertiary surface. The NaCl content of the water in the inclusions varied from 2.9 to 36 weight percent

suggesting that there were large changes in the salinity

of the.hydrothermal fluid during deposition.

Roedder (1971) concluded from fluid inclusion

studies of quartz that the molybdenite ores at both Bingham

Canyoh and Climax were'deposited at temperatures between

490 and 1000 K,. and pressures from 80 to 1100 atmospheres.

Similar values were obtained by Berzina and Sotnikov (1977)

for molybdenite-rich quartz veins in the Kuznetsk Alatau

and other Central Asian deposits. The quartz-molybdenite

veins in both the Kuznetsk Alatau and Eastern Transbaikalia

deposits apparently formed at temperatures between 490 and

750 K, and pressures up to 1700 atmospheres. In both of

these investigations, the salinity of the trapped fluids

panged from less than 5 to more than 60 weight percent

total salts. 142- Fluid inclusion evidence coupled with the solubility data indicate that the tungsten and molybdenum in the

Arizona deposits had to be transported in an acidic, saline fluid at temperatures above 475 K. The following observa tions are used to support this statement:

(1) CaMoO^, CaWO.^, FeMoO^, and FeWO^ are essentially insoluble in water at a pH of 6 to 7, a temperature of 29 8

K, and a pressure of 1 atmosphere.

(2) The alkaline earth molybdates and tungstates under- . go dissolution and chemical reaction when the pH of the solution is changed from neutral to more acidic.

(3) If the hydrothermal fluid had been alkaline, it could not have transported all of the iron needed to form both the wolframite and the associated pyrite, chalcopyrite, magnetite> and siderite. Instead, the iron would have pre cipitated -as Fe (OH) FeO(OH), FegOg'nHgQ, or Fe^O^ in the channelways somewhere between the heat source center

and the altered, highly fractured portions of the stock

cut by the sulfide-rich quartz veins.

Other factors in addition to temperature must in-

fluence the transport of the two heavy metals. An increase

in temperature from 298 to 573 K does not significantly

increase the solubilities of CaMoO^, CaWO^, FeMOO^, and

FeWO^ in either pure water or dilute saline solutions. In

fact, under some conditions, a temperature increase " 143 actually decreases the solubility of the molybdate or tungstate. Little is. known about the effect of chlorine on the transport of tungsten and molybdenum in hydrothermal

solutions„ However, the addition of large amounts of NaCl does not increase the solubility of an alkaline earth molybdate dr tungstate by.more than a factor of 10 at temperatures below 573 K„

6 »4 Stable Mineral Assemblages

.The sulfide-simple oxide primary mineral assemblage

is remarkably consistent, throughout the porphyry copper deposits of. Arizona and Sonorai Molybdenite, magnetite, minor bornite, and traces of rutile are commonly found with

the pyrite and chalcopyrite of the potassic alteration

zone. Wolframite- and arsenopyrite may also be present on

rare occasions. Sphalerite and galena are generally re

stricted to fissure, veins on the peripheries of the stocks.

Minor tetrahedr.ite-tehnantite and traces of argentite are

sometimes associated With the galena (e.g., at the Bluebird

vein in the Copper Creek Granodiorite).

The skarn zones formed by the intruding plutons

contain these same minerals>■with the possible exception .

of rutile, even.though.the silicate mineralogy is radically

different. In contrast, the tungsten mineralogy is strongly

dependent on the depositional environment. As a general

rule, wolframite is restricted to the central quartz veins . 144 of the stock. Scheelite, on the other hand, can exist in both skarn zones and potassic alteration zones (this study).

The scheelite in the central quartz veins of the stock, may have been deposited after the wolframite.

Pinkish-orange scheelite was found growing around the . perimeter of huebnerite stringers' in vein quartz at the

Hawk and Little Fanny claims northwest of Texas Canyon in

Cochise County. Lesser amounts of chalcopyrite, sphalerite, and galena were deposited along with the huebnerite. In the last stage of the mineralization, primary (?) covellite coated the chalcopyrite where vugs remained ■ in the quartz.

Burt (1971) , in his study of the Ca-Ee-W-O-C-F system^ pointed out that calcite and ferberite are not a stable equilibrium mineral pair. In the skarns, the fol lowing two regctibns apparently control tungsten deposition:

FeWO 4 + CaF2 + CCm + HO FeCOg + CaW04 + 2HF ferberite fluorite ' siderite scheelite

3FeWO4. •, .+• 3CaF2 + HO- + 3H_0 ^±r Fe^ + 3CaW04 +6 HF.. ferberite fluorite magnetite scheelite

Thus, wolframite-rich veins and greisens indicate a fluorine- rich, CO2-poor environment, while scheelite-rich skarns. indicate just the opposite. Field evidence in the Pinal,

Sierrita, Santa Rita, and Little Dragoon mountain ranges supports this observation. It is not known whether the 145 predominant fluorine species is ' S^F4 OF2,•or HOF.

The "peanut" ores of Nederland, Colorado, cannot be used in an argument against Burt’s hypothesis. The calcite and dolomite in the "peanut" ores were deposited after the ferberite. hovering and Tweto (1953) found that, the ferberite and quartz had been corroded where the two minerals were in contact with the carbonate,

.6.5 Activity-Activity Diagrams - for the ' : . Ca-Fe-Cu-M6-W-S-Q-H ■ System. In order to better understand the chemical reactions and mineral assemblages in the different alteration zones, activity-activity. diagrams were constructed.for the Ca-Fe-

Cu-Mo-W-S-O-H system and its-, various subsystems. ' The dis solution reactions used in the constructions are listed in

Table 36. The equilibrium constants of the different dis solution reactions were calculated over the temperature range from 29.8 t o 573 K. The pressure at each temperature is equal to the boiling point pressure of water. These constants are given in Table 37. The calculations were carried out using the. KELLYCOB computer program developed by Helgeson (1969) and modified by Dennis Norton and Jerry Knight (personal com munication, 1975). This program requires the input of values for the heat of formation, entropy, specific heat, Table 36= Dissolution reactions to bare ions for the system: Fe-Cu-Mo-W-S-O-H.

Copper Sulfides

Bornite , ' +? = Cu5FeS4 + 6 = 75 H + 0 = 50 H^O = 5 Cu + Fe +’ 0.125 SC>4 + 3.875-H^S (aq)

Chalcopyrite + +2 CuFeSg 4- 0 = 50 H^O + 2 = 75 H = Cu + Fe + 1 = 875 HgS (aq) + 0.125 S04

Covellite , . CuB + 0=750 H + 0.500 H^O = Cu + 0 = 125 SO^.. + 0.875 H^S (aq)

Iron Sulfides and Oxides

Pyrite . . ’ +2 . = . FeS2 + H^O + 1 = 5 H = Fe + 3,.75 (aq) + 0.25 S04

Magnetite ; „ . . = F ^ 3 ° 4 + 5"5 H + 0 = 25 H2.S (aq) = 3 Fe + 0 = 25 SQ4 .+ 3 H^O

Hematite ; + . +2 . := Fe203 + 0 = 25 H2S (aq) + 3.5 H = 2 Fe + 0.25 SC>4 + 2 H^O

Molybdenum and Tungsten Minerals

Molybdenite _ - _ , MoS2 + 0=25 S04 + 3 H20 = Mo04 + 2=25 HgS (aq) + 1.50 H

Tungstenite _ _ 146 WS2 + 0=25 S04 + 3 H20 = W04 + 2=25 H2$ (aq) + 1.50 H Table 36, continued

Molybdenum and Tungsten Minerals, continued

Molybdic acid Tungstic acid H^MoO, = 2 H + MoO. H2W04 = 2 H+ + WO, 2 4 4 Powellite +2 _ Scheelite 2 CaMo04 = Ca + MoO^ CaW04 = Ca + W04

Ferrous molybdate (synthetic) Ferberite „ FeMo04 = Fe^^ + MoO 4= FeWO.4 = Fe + WO. 4 147 148 Table 37. Equilibrium constants for the oxidation- reduction and hydrolysis of Ca^Fe-Cu-Mo-W-S- 0-H minerals in aqueous, solution at elevated temperatures

K(T) loSi0

Mineral 298 K 373 K • 473 K 573 K

Bornite V -79.4 -60.7 -43.6 -31.5 Chalcopyrite -22.1 -17.2 -12.6 - 9.33 Cove Hi te- -17.5 — 13.3 - 9.52 . - 6. 97

Pyrite — 13.6 -10.7 - 7.96 - 6.07 Magnetite +22.5 + 14.7 + 8.26 + 4.09 Hematite +13.9 + 8.99 + 4.76 + 1.97

Molybdenite -46.5 . ' -36.7 — 28.8 -23.9 Tungstenite — 39 .0 -31.2 -24.9 — 21. 0

Molybdic acid . -14.9 ' : -13.6 /; -13.1 -13.8 Tungstic acid -16.5 -14.8 -13.9 -14.3 Powellite - 8.80 - 8,95 - 9.74 -11.3 Scheelite -20.0 -18.0 -17.0 -17.4 Ferrous molybdate - 9.46 -10.1 -11.3 -12.9 Ferberite —11.0 . -11.4 -12.4 -13.9

Other Molyjpdates and Tungstates

Manganous molybdate - 4.86 — 6.38 - 8,94 -12.2 Huebnerite . -11.4 -11.6 -13.1 -15.6 Wulfenite -16.3 -14.8 '-14.4 -15.2 Stolzite -16.3 . -14.9 -14.5 -15.4 Sanmartinite -10.3 -10.7 -11.6 -13.1 ■ 149

and molar volume of each compound and ionic species, under

consideration (Appendix H) „

No attempt was made to calculate the log K of

reaction values above the critical point of water (647.2 K

and 217.7 atmospheres) because there is little thermodynamic

data available on the behavior of non-ideal ions in aqueous

fluids under such conditions. In some cases, it was neces-*

sary to estimate the entropies and heat capacities of key

complex anions using the method outlined by Criss and Cobble

(1964a and 1964b). A Criss and Cobble plot (absolute

entropy as a function of the charge to ionic radius ratio)

is shown in Figure 20 for selected cations.

Figure 21 is an activity-activity diagram for the

CUgS-FeG-HgS-HgSO^-HCl-HgO system at 573 K and 1 atmos

phere. This diagram can be used for pressures up to approxi

mately 500 atmospheres, because an increase.in pressure has

. only a slight effect on the equilibrium constants of aqueous

solutions in the temperature range from 298 to 573 K. The

vapor pressure of water at 573 K is 84.75 atmospheres.

The common logarithm of the H^S activity has been fixed at

-2.5 by the author in order to approximate observed

geologic conditions (Titley arid Hicks, 1966). If the

logarithm of the H^S activity is lowered to -4.0, the '

chalcopyrite stability field vanishes and hematite ap

pears (Figure 22). If the logarithm of the is less + 60

+ 40

+ 20

Li 0 + 2 Bo + 2Qo^oEu + 2

-20 , + 2

+ 2 -40 +2© ^ OGM 0 Fet°2 Ni + 3 — 60 L. + 3GTW -80 >3 Er+3 Tm+3 100 Ce + 4

120

140 4 1-- 1-- 1-- f 0 15 2 0 2 5 3 0 3 5 4 0 4 5 5 0 5 5 6 0- 65 70

Z/R in nm-1 The entropy of a cation in water as a function of the charge to radius ratio. 150 151

MAGNETITE

+ X.

CM CHALCOPYRITE o

2 — BORNITE o u> 3 PYRITE

C0VELL1TE

-G -12 -4 0

Log a [Cu+] / a [ h +]

Figure 21. Theoretical activity diagram for the system: Cu2S-FeS-H2S-H2S04-HCl-H20 at 1 atmosphere. Temperature = 573 K. Log a (H2S) = -2.5, a(H20) = 1.0. Figure 22. Theoretical activity diagram for the system: system: the for diagram activity Theoretical 22. Figure

Log a [Fe++] / a2 [h+] -6 6 — 12 Temperature = 573 K. Log aCl^S) = -4.0, -4.0, = aCl^S) Log K. 573 = Temperature Cu a(H 2 S-FeS-H 2 ) 1.0. = 0) Y ITE PYR E ATITE HEM 2 S-H MAGNETITE o a Cu]/ a / u+] [C a Log 2 -8 S 04 -HCl-H 20 COVELL1TE at at [ -4 1 h atmosphere. atmosphere. +] BORNITE 152 0 153 negative than -1.5, pyrrhotite forms instead of pyrite.

These activity diagrams are two of a set published by

Helgeson, Brown, and beeper (1969).

4- 4 . 4 - If the temperature is lowered while the Cu , Fe ,

and H activities are held constant, the stability fields

- for ■ chalcopyrite, bornite, and covellite will shift, mar- . kedly to the left. This.shift means that it is easier for

the three minerals to form at lower temperatures. On the

other hand, greater iron concentrations are required to

form magnetite at the lower temperatures. The small size -

of the chalcopyrite stability field at 573 K, coupled with

the fluid inclusion data and our limited knowledge of

mineral paragenesis, suggests.that much of the hypogene ore

in Arizona was deposited under chemical conditions similar

to those near the triple equilibrium point of pyrite,

chalcopyrite, and magnetite. Three observations support .

this conjecture:

(1) Ores from the potassic zones of most Arizona

porphyry copper deposits show the following sulfide abun

dance pattern: pyrite >_ chalcopyrite > molybdenite >>

bornite.; . ■

(2) At Ray and several other mines, a few quartz-

pyrite-chalcopyrite veins are cut in turn by quartz-..

magnetite veins, which are cut in turn by pyrite veins. 154 (3)■Magnetite from skarn zones in the Pima and Cuprite districts contain'blebs and microveinlets of both chalcopyrite and pyrite.

Figures 23 through 26 show what happens when molyb denum or tungsten is introduced into the system. In

Figures 23 and 25 the value of log [a(Cu 4* )/a(H 4- )] has been fixed at.-5.0 so that chalcopyrite can form. In Figures

24 and 26 the value of log [a(Cu+)/a(H+ )] has been in creased to -4.0 so that bornite will appear and displace the, pyrite and:; chalcopyrite stabi 11 ty fields. ., The absence : of ferrous molybdate restricts the composition of the initial hydrothermal solution in Figures 23 and 24 to the left side of the dotted line.

Figures 27 through 29 are attempts at combining the molybdenum data with the tungsten data. These last three diagrams offer an answer to the question raised ' earlier about the absence of ferrous molybdate and tung-

stenite in the porphyry copper deposits. The intergrowth; of pyrite and chalcopyrite in the different ores places boundary conditions on the iron, copper, and HgS activities.

Even when these boundary conditions are satisfied, molyb

denite can be formed from solution without depositing any

ferrous molybdate. However, if the thermodynamic values

are accurate, wolframite will frequently form instead.of

tungstenite. '. 155

6 ——-

x MAGNETITE

CHALCOPYRITE MOLYBDENITE\ ^ PYRITE

COVELLITE

— 6 -3 0

Figure 23. Theoretical activity diagram for the system: CU2S—FeS—H2S—H2SO4—H 2M0O 4—HC1—H2O at 1 atmos phere. Temperature = 573 K. Log a(H2S ) = -2.5, log a(Cu+ )/a(H+ ) = -5.0, a(H.O) = 1.0. 156

+ X CVJo

MOLYBDENITE O- o> BORNITE 5

-2 —

COVELLITE

-6 - 3 0 -22 -14 -6

Log a 2 [h + ] x a [moO =]

Figure 24. Theoretical activity diagram for the system: CU2S—FeS—H2S—H2SO4—H2MoO^—HCl—H2O at 1 atmos phere. Temperature = 573 K. Log a(H2S) = -2.5, log a(Cu+)/a(H+)=-4.0, a(H20) = 1.0. Figure 25. Theoretical activity diagram for the system: system: the for diagram activity Theoretical 25. Figure

Log a [Fe++] /a 2 [h+] — -6 2 —— — 30 -3 hr. eprtr = 7 K Lg a (H Log K. 573 = Temperature phere. CU 25 lg C+)aH = 50 aUO = 1.0. = a U^O) -5.0, = ) a )/a(H+ log (Cu+ -2.5, MAGNETITE TUNGSTEN ITE TUNGSTEN 2 S—FeS—H CHALCOPYRITE COVELLITE PYRITE 2 S—H Log q2 [h + ] x x ] + [h q2 Log 2 -22 SO 4 —H 2 O W 4 \ —HC1—H a[wO =] -14 2 a 1 atmos 1 at O 2 S ) = = )S —6 157 158

TUNGSTENITE

2 — \ £

BORNITE

-2 —

COVELLITE

-6

-3 0 -22 -14 — 6

Log o2 [H 4] x a [WO =]

Figure 26. Theoretical activity diagram for the system: Cu2S-FeS-H2S-H2SO4-112^04-HCI-H2O at 1 atmos phere. Temperature = 573 K. Log a(H2S ) = -2.5, log a (Cu+)/a(H+ ) = -4.0, a(H20) = 1.0. 159

— 10 —

o FERBERITE SATURATION X TUNGSTEN ITE

CD O

MOLYBDENITE

-2 2 -14

Log Q2[ h +] x a[MoO =]

Figure 27. Theoretical activity diagram for the system: Cu2S-FeS-H2S-H2S04-H2Mo04-H2W04-HCl-H20 at 1 atmosphere. Temperature = 573 K. Log a (H2S ) = -2.5, log a (Fe++)/a^(H+ ) = +3.0, log a(Cu+ )/a (H+) = -5.0, a (H20) = 1.0. 160

- 2

-10

ii O 5 FERBERITE SATURATION o X TUNGSTENITE — 18 — — x

CM O o

MOLYBDENITE CHALCOPYRITE — 26 —— CD

3 4 -3 0 -14 - 6

Log a2[H+] x a [Mo0 4= ]

Figure 28. Theoretical activity' diagram for the system: CU2S—FeS—H2S—H2SO4—H2M0O 4—H2WO 4—HCI-H2O at 1 atmosphere. Temperature = 573 K. Log a(HzS) = -2.5, log a(Fe++)/a2 (H+ ) = +2.5, log a(Cu+ )/a(H+) = -5.0, a(H20) = 1.0. 161

-2

| o FERBERITE SATURATION X z TUNGSTEN ITE

o o* 3 MOLYBDENITE

— 26 ——

B0RN1TE

Li. - 3 4 -3 0 -22 -14 -6

Log Q2 [ h +] x o [M o04=]

Figure 29. Theoretical activity diagram for the system: Cu2S—FeS—H2S—H2SO4—H2M0O4—H 2WO4 —HC1-H20 at T atmosphere. Temperature = 573 K. Log a (H2S) = -2:5, log a (Fe++)/a2 (H+ ) = +3.0, log a(Cu+)/a(H+ ) = -4.0, a(H20) + 1.0. 162 Because molybdenite and tungstenite are isostructural and have the same ionic charge-to-radius ratio, their entropies are almost identical. The same situation exists in the case of ferrous molybdate and ferberite. Therefore the differences in geochemical behavior observed between isostructural molybdenum and tungsten compounds must be due to differences in their enthalpies of formation. These enthalpy.differences are primarily dependent, in turn, on variations in atomic orbital bonding. As discussed in

Section 2.1, one reasonable explanation of these behavioral differences is that molybdenum deviates from the normal electron filling pattern and exhibits both,half-filled subshell stabilization and a d-s orbital cross-over, while tungsten does not. CHAPTER 7

CONCLUSIONS

Molybdenum and tungsten have almost identical

electronegativities and atomic radii, but behave differently

during both chondritic differentiation and the formation of porphyry copper deposits. Analyses of the different phases in chondrites have shown that molybdenum is geo-

chemically "schizoid"and can exhibit both siderophile and

chalcophile behavior. Tungstenj. on.: the . other hand, . is predominantly siderophile. The strong chalcophile tendency of molybdenum relative to tungsten is not explained by

simply comparing the electronegativities or ionic radii of

the two elementsi

In the porphyry copper environment, the bulk of the ■

tungsten forms either wolframite or scheelite. However,

part of the tungsten follows titanium and is incorporated

into minerals like rutile and magnetite. Another part

follows molybdenum and occurs as a trace element in molyb

denite and secondary wulfenite.• Under these conditions,

molybdenite and ferberite are preferentially deposited in

place of tungstenite and ferromolybdate. In theory, the

following reaction should occur:

163 164 WS2 + FeMo04 -- -a- MoS2 + FeWO^.

At a temperature of 573 K and a pressure of 400 atmos pheres , the equilibrium constant, K, for this reaction 3 9 equals 10 * . This value corresponds to a change in free energy of -43.1 kJ/mol.

The differences in the enthalpy of formation for molybdenite and tungstenite (and for ferberite and ferromolybdate) are apparently the result of certain atomic phenomena. Molybdenum and its neighbors: Nb, Ru, Rh, Pd, and Ag exhibit deviations from the normal orbital filling pattern. These deviations are due to the counterbalancing of 5s electron penetration phenomena by 4d half shell and ligand field stabilization effects.

In :tungs;te.n>• the 14 :v.4f;■ eleotrons. s.creen ,the 5s,

5p, 5d, and 6s electrons from the nucleus. The first ionization potential of tungsten is 0.88 eV higher than that of molybdenum. However, the f orbital screening effect causes the third and higher ionization potentials of tung sten to be lower than those of molybdenum. These lower +6 ionization potentials give the W cation greater stability ■ -f fi - than the Mo cation. This difference suggests that the

WC>4~ anion is more stable than the MoO^- anion.

Differences in the oxidation-reduction potentials of the two elements in aqueous solutions may also play a role in separating tungsten and molybdenum. Variations in . 165 the polymerization of the MoOg”^ and WOg-6 octahedra may have a significant effect on the two potentials when the pH. of the solution is more acidic than 6.5.

The molybdenum and tungsten minerals contain a number of key trace elements. Ti, Mn, S e , Ag, Te, W, Re, and Bi all occur in molybdenitev Moreover, the Arizona molybdenites seem to have-.an abnormally;high concentration of rhenium compared to.samples from other, parts of the world. Sc, Nb, and Ta are important trace elements at the part-per-million level in wolframite, but are at least an- order of magnitude smaller in oogenetic scheelite. The .. reverse is true for Sr, X, and Mo. Trace amounts of titanium and the rare.earths are present in.both tungstates.

Previous estimates of;the. Mo/W ratio in the crust • appear to be too low. . Isptopic properties' coupled with sparse whole rock ■analyses., indicate ■ that • the Mo/W ratio is at least 3:1. The existence Of large low-grade reserves of tungsten has been confirmed at the Twin Buttes mine and other Laramide copper-molybdenum deposits in southeastern

Arizona and northern Sonora. At current market prices, it

appears economically feasible to recover this tungsten from

the mill tailings of several of the mines. At Twin Buttes, the scheelite is associated, with the chalcopyrite, molyb denite , and pyrite. The scheelite and sulfides occur principally in altered limestones, but are also found in 166 quartz monzonite porphyry, arkos.e, and quartzite. Although

copper, molybdenum, and tungsten have been enriched at Twin

Buttes., the ratios, of their abundances, in the ore remain unchanged from the crustal values„ Since the tungsten does.not occur as a sulfide, it appears that the copper- molybdenum-tungsten enrichment mechanisms are independent of the amount of sulfur in the deposit. - APPENDIX A

COMPILATION OF K/ Ar AGE DETERMINATIONS OF LARAMIDE : • INTRUSIVES IN SOUTHEASTERN ARIZONA THAT ARE ASSOCIATED WITH COPPER-MOLYBDENUM OR COPPER-TUNGSTEN MINERALIZATION .

References used in the last column are identified as: Al - Banks et al„, 1972

A2 - Creasey, 1965b

A3 - Creasey and Kistler, 1962

A4 - Damon, 1964

A5 - Damon, 1970

A 6 - Damon and Mauge'r, 1966

A7 - Damon and Shafiqullah, personal communication, 1977

AS - Drewes, 1970

A9 - Drewes, 1971b

A10 - Johnston, 1972

All - Livingston et al., 1967

A12 - Marvin et al., 1973

A13 - Mauger, 1966

A14 r- McDowell, 1971

A15 - Pushkar and Damon, 1974

A16 - Rose and Cook, 1966

A17 - This study

A18 - Kelly, 1977

167 Age Refer- Location and Sample No. Rock Mineral • (m.y .) ence

GILA COUNTY:

Copper Cities mine, Miami Ore body Hydro- 63 A2 33°27 ' N , 1.10°5;2 ' 3 0 " W thermal Biotite

Miami, hear the Miami Copper Co. Barren granite . Biotite 55.8± A5 •concentrator (PED-10-69) •intruding mineralized . 1.3 33o24V20H N, ii0o51,58" W Pinal Schist

Christmas mine, Dripping Springs Quartz diorite Biotite 64.5 A3 Mountains porphyry 33°04' N, 110 44' w

PINAL COUNTY:

2.0 km north of Schultze Ranch, Schultze Granite Biotite 57.6 + A14 west of Miami, Pinal Mountains (quartz monzonite) 1.7 (L-846) - 33 23'19" N, 110 55'00" W

Pearl Handle pit, Ray mine ore- 1 cm books of biotite Biotite 67.0 + A1 body, Dripping Spring Mountains ; intergrown with molyb-. 1.1 (NOs. 19 & 20) denite, chalcopyrite, , ’ 66.7 + 33^10'27" N, 110 59'37" W and quartz 1.1 Copper Hill, 13 km west-southwest Quartz mohzonite Biotite 69.5± of Winkeimart, Tortilla Mountains 1.6 (PED—27-61) U. 168 32°58' N, 110 51' W Age Refer- Location, and Sample No, Rock Mineral (m.y.) ence

PINAL COUNTY: \

Ray, along Highway 177 in Copper Granite Mountain Biotite 66+2 A3 Canyon, DrippingnSpring Mountains Porphyry (porphy- (No, 14) 33^10 ' 45" N, 111 02 '.24" W ritic granodiorite) Biotite 60 A16

Biotite 59.5+ A14 (L-850) 1.8

Biotite 61.0+ A1 : 1.2 Rare Metals mine, near Zelle- Quartz monzonite Biotite 6 4.6 i A5 weger Wash, Tortilla Mountains porphyry dike . 1.5 (PHK-5^69) . n 33°05126" N , 111 01*56" W

San Manuel mine, Black Hills Granodiorite Hydro- 65 A2 32°411 00": N> 110 41' 30" W porphyry thermal Biotite

Copper Creek, Galiuro Mountains Copper Creek Biotite 71 A3 32038'30" N, 110O30'00" W Granodiorite .

Copper Creek, Galiuro Mountains Andesite porphyry, Biotite 65.7+ A17 0,3 km south of the ruins of the late stage of the 1.5 Copper Creek post office Copper Creek 32044'50" N, 110o28'43" W Granodiorite • Age Refer Location and Sample No.. . . Rock Mineral (m.y.) ence

PINAL COUNTY (continued):

Copper Creek, Galiuro Mountains, Metamorphosed andesite Whole 62.7+ A17 0.5 km MW of the.Glory Hole mine member of the Glory Rock 1.4 32°45'45” N, 110O29‘45" W . Hoie volcanics

Poston Butte, drill hole through Mineralized Biotite 63.4+ A7 alluvium and Precamhrian Oracle granodiorite 1.5 Granite into granodiorite, Florence (UAKA 72-23/CONOCO) 33°02'48" N, 111025'45" W.

Pediment south of the Sacaton Mineralized quartz Biotite 66.0+ A15 Mountains, ASARCO drill hole monzonite porphyry 1.4 #S-9 at 754-767 ft, Casa Grande with sericite and (PED-12-70) n kaolinite . 32°57'10” N , 111 49'10" W

Lake Shore mine fj. Slate Mountains Mineralized quartz Sericite 64.2+ A10 32°31'24" N , 111 54'08" W monzonite porphyry 2.1 phase of stock

Lake Shore mine. Slate Mountains Quartz monzonite Biotite 67.3± A10 32°31'24" N , 111 54'08" W porphyry stock 2.2

PIMA COUNTY

El Tiro pit. Silver Bell Mineralized quartz Biotite 64.8+ A13 Mountains (PED-2-63) monzonite with • 1.5

32025'42" N, 111032'12" W . supergene leaching 170 Age Refer- Location and No. Rock Mineral (m.y.) ence

PIMA COUNTY (continued) :

El Tiro pit, Silver Bell Mineralized quartz Biotite 67.1+ A13 Mountains (PED-3-63) • monzonite / . 1.6 32°25'42" N, .111032,.12" W

.1.8 km west of the Cuprite mine, Quartz monzonite Biotite 75.5± A12 north of Mt. Fagari,.. Santa Rita 2.6 Mountains 31°55150" N , 110 43'36" W .

Helvetia, Santa-Rita Mountains Quartz latite por- Biotite 57.6+ A9 . - (No. .1245) , ; ■ J- Phyry plug 2.1 31°51 ’ 45” :N> 110 47 ' 00" W

King mine, northeast, of Helvetia Quartz latite por Biotite 57.2+ A9 Peak, Santa Rita Mountains phyry plug 2.1 (No. 1185) 31°51'15" N, 110 45'30" W

Ophir Gulch, 3. km west of Quartz latite por Biotite 57.0+ A 8 Greaterville > Santa Rita phyry plug 2.2 Mountains n ' 31°46"00".N, 110 46'45" W

• Butte, tjojrth of' Hilton Ranch, Quartz monzonite Biotite 71.9+ A12 Empire Mountains 2.5 3 1 ° 5 4 '' N, il0°381 W Age Refer Location and Sample No. Rock ■ Mineral (m.y.) ence

Northwest corner of the Phelps New Cornelia Biotite 62.6+ A14 Dodge., New Cornelia pit, Little Quartz Mpnzonite 1.9 Aj-o Mountains (L-843) 32°2I'32" N, 112 52'12" W

Phelps Dodge .New Cornelia pit. Quartz-orthoclase- Biotite 64.6+ A.4

Little- Ajb Mountains (RM-2-62) biotite pegmatite 2.2 . 32°21'31" N, 112952100" W

ANAMAX Twin Buttes pit, eastern Porphyritic quartz Biotite 57.1+ A18 pediment of Sierrita Mountains, monzonite 2.1 2850 ft elevation 31°54*25" N, 111902'19" W 1

ANAMAX Twin Buttes pit, eastern Aphanitic quartz , Biotite 58.6± A18 pediment of sieirita Mountains, monzonite porphyry 2.5 2750 f t .elevation 31954 ' 18" N, Hl°02'27" W

Duval Sierrita-Esperanza Coarse biotite vein- Biotite 62+3 A12 property, copper prospect 2.6 km lets in diorite K- 58+3 WNW of the Esperanza pit, feldspar Sierrita Mountains 31953' N, 111909' W

Esperanza pit, Sierrita Mountains Muscovite-quartz Musco- 62.0+ A 6 (RM-3-62) _ veinlet in miner vite 1.4 31952'00" N, 111 07'42" W alized rock

H Age Refer- Location and Sample No. Rock Mineral (m.y.) ence

PIMA COUNTY (continued)

Esperanza pit, Sierrita Mountains Phlogopite-sericite- Phlogo- 64.0+ A6 (RM—1—62) _ sulfide rock pite 1.5 31°52'00" N, 111 07142" W

ANAMAX property, Twin Buttes, Porphyritic quartz Biotite 54.7+ A 6 eastern pediment of Sierrita monzonite 1.3 Mountains (RM-3-64) 31° 5 4117" N , i11° 0 2'3 4" W

Pima mine, east of Mineral Hill, Sericitic vein halo Sericite 57.2± A7 northeastern edge of the : ■ 1.2 Sierrita Mountains (UAKA 75-118) 31°59' N, lll°041 W

Cuprite mine, north of Mt. Fagan, Quartz diorite stock Biotite 75.4+ A12 Santa Rita Mountains 2.8 31°55'20" N, 110°42'30" W

SANTA CRUZ COUNTY,

Madera Canyon, south of the Madera Canyon Biotite 69.5+ A 6 Santa Rita Lodge (RM-6-63), Granodiorite 1.6 Santa Rita Mountains 31°42,54" N, 110°52’12" W 173 Age Refer- Location and Sample No. Rock Mineral (m.y.) ence

SANTA CRUZ COUNTY (continued)

At top of Washington Pass, Granodiorite Biotite 65.41 A6 Sycamore Canyon, Patagonia (Quartz diorite of (RM-7-63) 2.0 Mountains Damon and Mauger, 31°23'12" N, 110 43'06" W 1966) Biotite 6213 A12

Horn- 60+5 A12 blende

Southwest side of Mt. Washing Quartz monzonite Biotite 60+3 A12 ton , 1 km northwest of Inter phase of grano national Border Marker 115, diorite pluton Patagonia Mountains 31°20'30" N> 110°44'45" W

COCHISE COUNTY

0.5 km south of the Triangle T Texas Canyon Biotite 49.61 All turnoff from Interstate 10, Quartz monzonite 2.5 Texas Canyon, Little Dragoon Mountains (PED-11-60) Musco- 48.51 All 32°02'16" N, 110°05'41" W vite : . 1.2 55.51 1.3 174 Age Refer- Location and Sample No. Rqck Mineral (m.y.) ence

COCHISE COUNTY (continued)

Road cut along Interstate 10, Texas Canyon Biotite 53.3+ All Texas Canyon, Little Dragoon Quartz Monzonite 1.3 Mountains (PED-6-64) 52.3 + 32°021 N, 110°061 W 1.2

Musco- 53.7+ All vite 1.3

Texas Canyon, Little Dragoon Texas Canyon Biotite 51+3 A12 Mountains Quartz Monzonite 53 + 3 32006' N, 110 05' W

Reef Mine, Carr Canyon, Quartz sill in-' Sericite 47.8+ A17 Huachuca Mountains (UAKA 75-115) truding Cambrian 1.0 31°25'37.5" N, 110 17'16.8" W Bolsa Quartzite 175 APPENDIX B

4 n 40 COMPILATION OF K/ Ar AGE DETERMINATIONS OF OLIGOCENE AND MIOCENE INTRO'S IVES IN SOUTHEASTERN ARIZONA

References used in the last column are identified as: B1 - Bikerman, 1967

B2 - Damoh and Bikerman, 1964

B3 - Damon, 1965

B4 Damon, 1969 B5 - Damon and Shafiqullah, personal communication, 1977

B6 - Drewes, 19 7la

B7 - Marvin et al., 1973

B 8 - This study

176 Age Refer- Location and Sample No. Rock Mineral (m.y.) ence

MARICOPA COUNTY

South end of Central Avenue, South Mountain Biotite 19.2+ B5 South Mountain Park, South Quartz Monzonite 0.5 Mountains, Phoenix (UAKA 73- 110/CONOCO) 33o 20'29” N, 112 04'52" W

PINAL COUNTY

Picacho Mountains, southeast of North Star Grano- Biotite 24.3± B5 Picacho Reservoir (UAKA 73- ' diorite stock in- 0 .8 64/CONOCO) _ . truding Precambrian 32°48106" N, 111 21'18" W . Oracle Granite (quartz monzonite)

PIMA COUNTY

Las Guijas Mountains, General Muscovite veinlet in Musco- 30.01 B8 Electric II mine (UAKA 75-105) an andesitic dike vite 0.7 31q 39'25.5" N, 111022'44.5" W

Las Guijas Mountains, General Andesitic dike in the Whole 31.4 + B 8 Electric II mine (UAKA 75-105a) Las Guijas Alaskite Rock 0.7 31 ° 3 9 '25,5" N, 111°22 ' 44 . 5". W

Kitt Peak, Quinlan Mountains Sphene-bearing Biotite 28.11 B2 (PED-2-62) granite 0.7 31°58'12" N, 111 35'30" W Age Refer- Location and Sample No. Rock Mineral (m.y.) ence

East of Pirate Fault and south of Samaniego Granite Biotite 39.4+ B5 Mogul Fault, Santa Catalina 1.0 Mountains (PED-27-57) Coordinates uncertain

La Tortuga Butte, Roskruge Granodiorite Plagio"- 34.1+ B1 Mountains (MB-9-64) clase 0.3 32°09'16" N ,111°26'36" W

ASh Creek, Rincon • Quartz monzohite Biotite 23.5+ B7 Mountains 0.9 32°071 N, 110 28” W :

Ash Creek, Rincon Mountains Quartz monzonite Musco 24. 8 + B7 32°07' N, 110°281 W vite 0.9

Hidden. Pasture, Rincon Mountains Granodiorite Biotite 26. 3± B7 32907' N, 110°25' W 0.9

Deer Creek, Rincon Mountains Granodiorite Biotite 27.3 + B7 (69D93) 1.1 32912' N, 110 27' W

Deer Creek, Rincon Mountains. Pegmatite within . Musco- 36.8± B7 (69D95) granodiorite stock vite 1.6 32912' N, 110 27' W 178 Age Refer- Location arid Sample No. Rock Mineral (m.y.) ence

SANTA CRUZ COUNTY

Josephine Canyon, 4 km west Rhyodacite vitrophyre Horn- 27.8± B6 of Salero Ranch, Santa Rita laccolith blende 2.2 Mountains (No. 581) , 31°35'35" N, 110°55,35" W

West side of Sari Cayetano Peak, San Cayetano Biotite 27.6± B6 San Cayetano Mountains (No. 687) Granodiorite 1.3 31°32115" N, 110°59'00" W

GRAHAM COUNTY

Stockton Pass, east of Gillespie Mt. Graham Quartz Biotite 36.5+ B5 Wash, on Highway 226, Graham Monzonite intruding 0.8 Mountains (UAKA 73-147) gneiss 32°33'07" N, 108°44'52" W

Bufford Hill, Santa Teresa Rhyodacite dike swarm Biotite 24.6+ B5 Mountains (UAKA 74-129/CONOCO) in Precambrian - 0.6 32045»42" N, 110o08'07" W ' granite

COCHISE COUNTY .

Cochise Stronghold, Dragoon Stronghold Quartz Biotite 26±2 B7 Mountains Monzonite 31°561 N, 110 00' W

Cochise Stronghold, Dragoon Stronghold Quartz Biotite 22.3+ B2 Mountains (CMB-1-62) Monzonite 0.7 31°55 * 24" N, 109°58'00" W Age Refer- Location and Sample No, Rock Mineral (m.y.) ence

COCHISE COUNTY (continued)

CoChise Stronghold, southeast of Stronghold Quartz Biotite 23.4+ B5 Rockfellow Dome, Dragoon Monzonite 0.6 Mountains (UAKA 72-67) 310 55' N, ip9°581 W

Cochise Stronghold, Dragoon Stronghold Quartz Biotite 25.9+ B7 Mountains Monzonite 2.0 31056' N, 109 59'50" W

Hill 5052, Circld I Hills, north Circle I Granite Biotite 28.3+ B5 of Willcox (UAKA 73-13/CONOCO) intruding schist 0.6 32 25' N, 109°501 W

Ninemile Ranch, Ninemile Creek, Ninemile Granodiorite Biotite 29.6+ B3 Dos Cabezas Mountains (RCE- 1.4 622-64) /I. 32°13'30" N, 109 28'40" W

Jhus Canyon, 3 km northwest of Jhus Canyon Biotite 29.6+ B5 Galeyville, Chiricahua Mountains Quartz Monzonite 0.7 (PED-8-69) • _ 3158'02" N, 109 14'32" W

Jhus Canyon, 3 km northwest of Jhus Canyon Biotite 31.7+ B7 Galeyville, Chiricahua Mountains Quartz Monzonite 1.2 31°59' N, 109°14' W

Anderson Canyon, Chiricahua Moun Granodiorite Biotite 30.7+ B7 180 tains 32 06' N , 109o24' W 1.1 APPENDIX C

. SEMIQUANTITATIVE EMISSION SPECTROGRAPHIC ANALYSES OF MOLYBDENITE

The analyses were made by Hal W, Johnson, Pacific.

Spectrochemical Laboratory, Los Angeles, California.

181 182

PHK-9-67: Molybdenite, Buena Vista mine, southeast side of Providencia Canyon, Patagonia Mountains, Santa Cruz County, Arizona. 31°22 * 45" N, 110°46 ' OS11 W. The molybdenite occurs in a quartz vein with chalcopyrite, pyrite, and black rutile. The quartz vein follows a fracture in the propylitized, Paleocene biotite granodiorite. Se was not determined.

Mo 53.0 MoS2 . 88.4 %

Mg 0.010 MgO 0.017 A1 . 0.41 AI2O3■ 0.77 si 1.6 SIO2 3.4 Ca 0.064 Cab 0.090 Fe 3.6 FeS2 7.7 Cu 0.014 CuS. 0.021 . Sr tr< 0.01 SrO tr< 0.01 Ag 0.0043 Ag2S 0.0049 Pb .. 0.43 PbS 0.49

Total 101.0 % B nd< 0.007 Na " 0.10 K " . 0.30 Ti " 0.002 V " 0.004 Cr " 0.002 Mn ■ " 0.003 Zn . . " 0.06 Ga " 0.05 Ge " 0.01 Nb " 0.08 Ru " 0.02 Rh " 0.03 Sn " 0.01 Sb " 0.03 Te " 0.10 Ta ' " 1.0 W " 0.10 Re " 0.07 Pt " 0.01 Tl " 0.80 Bi " 0.002 U " 0.30 183

PHK-10-68: Molybdenite, Nunatak molybdenum prospect, Muir Inlet, Glacier Bay National Monument, Alaska. . 58°591 N, 136o061 W. The molybdenite is as sociated with pyrrhotite and chalcopyrite. The sulfides occur in quartz veins related to a quartz monzonite porphyry stockwork. Se was not determined.

MO 46.5 % 77.6 % MoS2 Mg 0.046 MgO 0.076 A1 1.8 AI 2O 3 3.4 Si 2.9 Si02 6.2 Ca 3.7 CaO . 5.2 Mn - 0 .13 MnS . . 0.21 Fe 2.3. FeS2 4.9 Cu 0.00046 CuS 0.00069 Sr 0.13 SrO . . 0.15

Total . 97.7 % B ndc 0. 007 Na It 0.10 K « 0.30 Ti II 0.002 V 81 0.004 . Cr II 0.002 Zn II 0.06 Ga II 0.05 Ge 11 0.01 Nb II 0.08 Ru 11 0.02 Rh II 0.03 Ag II 0.0002 Sn II 0.01 Sb 11 0.03 Te II 0.10 Ta 11 1.0 W ■ " 0.10 Re 91 0.07 Pt II 0.01 Tl 81 0.80 Pb II 0.08 Bi ' I! 0.002 U II 0.30 184

PHK-14-68: Molybdenite, Saddle between Mt« Democrat and Mt. Cameron, Buckskin Gulch, Ten Mile Range, southeast of Climax, Park County, Colorado. 39°20 * 35" N, 106°07153". W. The molybdenite occurs in a pegmatite with quartz muscovite, chalcopyrite, and feldspar. Se was not de termined.

M6 57.0 % 95.1 MoS2 Mg. 0.0061 " MgO ' 0.010

Al 0.031 AI2P 3. . 0.059 Si . 1.2 SiQo 2.6 Ca 0.68 CaO 0.95 Fe : 0.065 FeS2 0.14 Cu 0.0018 CuS . 0.0027 Sr tr< 0.01 SrO 0.012 Ag 0.0025 Ag2S 0.0029

. Total 98.8 : % B nd< 0.007 Na " " 0.10 K " 0.30 Ti *• 0.002 V " 0.004 Cr ' " 0.002 Mn . " 0.003 Zn " 0.06 . Ga " 0.05 Ge , ". 0.01 Nb , " 0.08 ■ Ru " 0.02 Rh " 0.03 Sn " 0.01 Sb " 0.03 Te " 0.10 Ta " 1.0 . M ■; " 0.10 Re " 0.07 Pt " 0.01 Tl " 0.80 Pb " 0.08 Bi 81 0.002 U " 0.30 185

PHK-5^-69: Molybdenite r Rare Metals mine, Zelleweger Wash, ■1.7 km south of the Gila River, Grayback Quad rangle , Tortilla Mountains, Pinal County, Arizona. 33°05'26” N, 111 01'56" W. Quartz veinlets occur along the Contact between altered Precambrian Ruin.Granite and a Laramide quartz monzonite porphyry dike. The quartz veinlets. contain molyb denite rosettes and chalcopyrite. Se was not determined.

Mo 50.5 % MoS0 84.3 2 B 0.010 B 2O 3 • 0.032 Mg 0.0068 MgO 0.011 Al 1.4 A I 2O 3 ■ 2.6 Si : 3.1 Si02 6.6 : Ca 0.14 CaO 0.20 Ti tr< 0.002 Ti02 ' tr< 0.003 Mn 0.13 MnS ' ■ 0.21 Fe ■ 1.4 FeS2 3.0 CU . 0.099 CuS 0.15 Zn r ■ 0.69 ■; ZnS" 1.0 Ag 0.0015 Ag2S : . 0.0017 Pb 0.12 PbS . 0.14

Total . - 98.2 Na i nek0.10 K " 0.30 V . " 0.004 Cr " 0.002 Ga " 0.05 Ge " 0.01 Sr ;■ " 0.01 - Nb M 0.08 Ru " 0.02 Rh ” 0.03 Sn " 0.01 Sb " 0.03 Te " 0.10 Ta " 1.0 W " 0.10 Re " 0.07 Pt " 0.01 Tl ^ " 0.80 - Bi " 0.002 U " 0.30 186

PHK-7-69: MolybdeniteBuena Vista mine, near the village of Santa Ana; 6 km southwest of the village of Santa Rosa and 24 km west of Yecora, Sonora, Republic of Mexico. 28023'07" N, lOgOOS'SS" W. Molybdenite occurs with pyrite, orthoclase, sericite, chlorite, and tourmaline in altered quartz monzonite of baramide age. Se was not determined.

Mo 58.5 % MoS2 97.6 %

B tr< 0.007 b 2°3 trc 0.02 Mg . 0.017 MgO . 0.028 Al 0.29 a 12°3 . 0.55 Si 0.54 Si02 1.2 Ca 0.15 CaO 0.21 Ti 0.0045 Ti02 0.0075 Fe : o.ie ' FeS2 .. 0.34 Cu 0.0030 CuS 1 0.0045

- Total 100.0 % Na ?; nd<0.10 K " 0.30 V " 0.004 Cr " 0.002 ; : : Mn -' " 0.003 zn " 0.06 Ga " 0.05 Ge ' " 0.01 Sr " 0.01 Nb " 0.08 Ru " 0.02 Rh " 0.03 . Ag " 0.0002 Sn " 0.01 Sb " 0.03 Te " 0.10 Ta " 1.0 W " 0.10 Re " 0.07 Pt " 0.01 Tl " 0.80 Pb " 0.08 Bi " 0.002 U " 0.30 - 187

PHK-llb-69: Molybdenite, Santo Nino mine, Mt. Washington, Patagonia Mountains, Santa Cruz County, Arizona. 31°21'41" N, 110°43"03" W. Molyb denite and chalcopyrite are disseminated in vuggy, altered pink granodiorite of Paleocene age. Se was not determined.

Mo 57.0 % Mo S 2 95.. 1

Mg 0.016 MgO 0.027 Al 0.45 AI2O 3 0.85 Si 1.2 Si02 2.6. Ca 0.026 CaO 0.036 Fe 0.17 FeS2 0.37 Cu 0.059 CuS 0.089

Total 99.1 B ndc 0.007 Na 11 0.10 K H 0.30 Ti » 0 .002 V n 0.004 Cr n 0.002 Mn fi 0.003 Zn H 0.06 Ga ' ' n - 0.05 Ge 11 0.01 Sr . n . 0.01 Nb 11 0.08 Ru 11. 0.02 Rh 11 0.03 Ag « 0.0002 Sn 11 0.01 Sb 11 0.03 Te n 0.10 Ta 81 1.0 W II 0.10 Re II 0.07 Pt « 0.01 Tl H 0.80 Pb II 0.08 Bi II 0.002 U II 0.30 188

PHK^15-69: Molybdenite, Santo Nino mine, Mt. Washington, Patagonia Mountains, Santa Cruz County, Arizona. 31°21141" N , 110 43'03" W. Molyb denite, chalcopyrite, and biotite are dis seminated in calcite-rich, altered granodiorite. Sericite fills cracks in some of the molybdenite. Se was not determined.

Mo 57.7 % MoS_ 96.3 - • ■ 2 Mg 0.0036 MgO 0.0060 Al . 0.52 AI2O3 . 0.98 Si 0.95 Si02 2.0 Ca 0.015 CaO 0,021 Ti tr< 0.002 Ti02 tr< 0.003 Cr 0.0030 Cr203 . 0.0044 Fe 0.086 FeS2 0.19 Cu 0.0016 . CuS 0.0024

Total 99.5 B nd< 0. 007 Na " 0.10 K . " 0.30 . V ". 0.004 Mn " 0.003 Zn " 0.06 Ga " 0.05 Ge " : 0.01 Sr " 0.01 Nb ■- " 0.08 Ru . " . 0.02 Rh ' " 0.03 Ag " 0.0002 Sn " 0.01 Sb " 0.03 Te " 0.10 Ta " 1.0 W " 0.10 Re " 0.07 Pt " 0.01 Tl " 0.80 Pb " 0.08 Bi " 0.002 U * 0.30 189

PHK-17-69: Molybdenite, Main haulage level of the Childs- Aldwinkle mine , Copper Creek, Galiuro Mountains, Pinal County, Arizona. 32o45,04u N, 110°28'57" W. Rosettes of molybdenite 5 mm in diameter are intergrown with 4 x 2 x 2 mm quartz crystals in altered, granodforite of Paleocene age. The ; granodiorite also contains 1 mm blebs of chalco- ' pyrite. Se was not determined..

Mo 58.2 % MoS2 97.1

Mg 0.015 MgO . 0.025 A1 0.017 AI2O3 0.032 Si 0.82 . Si02 1.8 Ca 0.022 CaO 0.031 Pe 0.072 : FeS2 . 0.16 Cu 0.048 CuS 0.072 W 0.14. MSg 0.19

Total : 99.4 B . nd< 0.007 Na 11 0.10 • K 11 0.30 Ti • " 11 •' 0.002 V U 0.004 Cr .. 11 0.002 Mn . 11 0.003 Zn 11 0.06 Ga 11 0.0:5 Ge 11 0.01 Sr 11 " 0.01 Nb 11 0.08 Ru II 0.02 Rh 11 0.03 Ag II 0.0002 Sn « 0«01 Sb II 0.03 Te II 0.10 Ta . II ' 1.0 Re 11 0.07 Pt » 0.01 Tl II 0.80 Pb II 0.08 Bi II 0.002 u 11 0.30 190

PHK-23-69: Molybdenite, Southeast corner of the ASARCO El Tiro pit. Silver'Bell Mountains, Pima County, Arizona; 32°25142" N, 111032,12" W. Molyb denite selvages line 0.7 to 1.8 cm wide quartz veinlets that cut calcite-rich altered alaskite. Blebs of chalcopyrite and pyrite occur in both the veinlets and the altered wall rock. Seri- cite coats some of the molybdenite rosettes in the tactite zones. Se was not determined.

Split. #1 ■/ Split #2; Split #1 ■ Split :

Mo 50.0 % 46.2 % MoS2 83.4 % : 77.0 B tr< 0.007 ndc 0.007 B2O3 trc 0.02 -- Mg 0.010 0.014 MgO . 0.017 0.023 Al 0.71 0.77 AloO-i 1.3 1.5 Si . 2.8 4.2 Si02r 6.0 9.0 Ca 2.7 3.7 CaO 3.8 5.2 Ti, trc 0.002 nd< 0. 002 TiOf trc 0.003 v Mn 0.17 0.22 MnS 0.27 0.35 Fe 1.0 1.7 FeS2 2.1 3.7 Cu 0.061 0.054 CuS 0.092 0.081 Sr 0.058 , 0.17 SrO 0.069 0.20 Ag tik 0. 0002 nek 0 . 0002 A g 2’S t r 0.0002 R e . 0.12 ndc 0.07 Res 9 o.i6 Pb 0.19 0.37 - PbS 0.22 0.43

Total 97.5 , 97.5

PHK-27-69: Molybdenite, Unknown locality, Telemark district, southeastern Norway. 29°N, 8° E. The sample was taken from a 3.8 x 2.2 x 1.5 cm single crystal that had a few inclusions of quartz, iron sulfides, muscovite, and feldspar. The crystal also had some limonite staining. Se was not determined.

Mo 58.0 % MoS'2 96.8

B tr< 0.007 B 2O 3 tr< 0. 023 Mg ■ 0.0078 MgO 0.013 Al. 0.36 AI2O3 0.68 Si 0.49 Si02 ■ 1.0 Ca 0.0088 CaO 0.01:2 Mn , 0.22 : MnS 0.35 Fe 0.48 ' FeS2 1.0 Cu 0.0030 CuS 0.0045 W ' tri 0.10 WS„ tr< 0.13 2

Total 100.0 Na ndc 0.10 K " 0.30 . Ti " 0.002 V " 0.004 Cr " 0.002 Zn " 0.06 Ga " 0.05 Ge ". 0.01 Sr " 0.0.1 Nb " 0.08 Ru " 0.02 Rll " 0.03 Ag " 0.0002 Sn " 0.01 Sb " 0.03 Te " 0.10 Ta " 1.0 Re " 0.07 Pt " 0.01 Tl " 0.80 Pb ■ " 0.08 Bi . " 0.002 ; U " 0.30 192

PHK-28-69 : . Molybdenite,. Unknown locality-, 'Chungking dis trict, Szechwan Province, People's Republic of China.. 29°30' N, 106° E. The . sample was taken from a molybdenite book, 3 cm in diameter. Se .was not determined.

Mo 58.4 % MoS2 97.4

Mg 0.0029 MgO 0.0048 Al tr<0.004 AlgOs tK0.008 Si 0.79 Si02 1.7 Ca tr< 0.0004 CaO tr< 0.0006 Fe .. . 0.12 FeSo > 0.26 Cu 0.00038 CuS 0.00057 W tr< 0.10 W S 2 trc 0.13

Total - , 99.4 B nd< 0.007 Ha . 0.10 K II 0.30 Ti II 0.002 V 11 0.004 Cr . . II 0.002 Mn II 0.003 Zn II 0.06 Ga 8? 0.05 = Ge II 0.01 Sr II 0.01 Nb • 11 ' 0.08 Ru II 0.02 Rh 11 0.03 Ag II ‘ 0.0002 Sn II 0.01 II Sb 0 . 03 Te II 0.10 II, Ta 1 . 0 Re II 0.07 Pt II 0.01 Tl 11 0.80 Pb II 0.08 Bi 11 0.002 U II 0.30 193

PHK-38-69: Molybdenite, Greisenized vein of quartz cutting the Schultze Granite (quartz monzonite), Bronx . mine,' 1.8 km northeast of Pinal Ranch, Gila County, Arizona. 33°21t56'u N, 110o58,34" W. Flakes, of molybdenite are intergrown with sericite and cubes of purple fluorite in quartz veins and veinlets. Se was not determined.

Mo 5.4.1 % MoS2 90.3 %

Mg. 0.021. MgO 0.035 A1 1.1 , AI2O.3 : 2.1 Si 2.2 Si02 4.7 Ca 0.029 CaO 0.041 Ti 0.064 Ti02 0.11 Fe 0.42 FeS2 0.90 Cu . 0.0045 CuS 0.0068 Sr tr< 0.01 SrO tr< 0.01 Ag , tr< 0.0002 A g 2S tr< 0 . 0002

Total 1 98.2 B ncK 0.007- ; Na " 0.10 K " 0.30 V " 0.004 Cr " 0.002 . Mn w 0.003 . Zn - - - n 0.06 - . Ga . " 0.05 Ge " 0.01 Nb " 0.08 Ru ' .' - " 0.02 Rh " 0.03 Sn " 0=01 Sb " 0.03 Te " 0.10 Ta " 1.0 W " 0.10 . Re " 0.07 Pt : ■" 0.01 Tl " 0.80 Pb " 0.08 Bi " 0.002 U " 0.30 194

PHK^20b-71: Molybdenite, Quartz'-cemented granodiorite breccia pipe. Main .haulage level of the Childs-Aldwinkle mine, Copper Creek, Galiuro Mountains., Pinal County, Arizona. 32°45 1 04" N, 110°28157" W. Molybdenite rosettes up to 8 mm in diameter are intergrown with 5. mm tall x 1.5 mm wide quartz crystals. Thin crystals of gypsum have formed on top of the rosettes. Se was not determined.

Mo 58.7 % MoS2 97.9

Mg 0.0079 MgO 0.013 A1 0.031 AI2O3 0.059 Si . 0.62 SiOn 1.3 Ca 0.019 CaO 0.027 Ti tr: 0 .002 Ti02 tr<'0.003 Mn 0.022 MhS 0.035 / Fe 0.0 80 FeS2 0.17 . Cu 0.0016 CuS : . 0.0024 W tr< 0 .10 W S 0 . tr< 0.13 / . -

Total 99.6 B nd< 0.007 Na » 0.10 K 1! 0.30 V • $1 0.004 Cr 1! . 0.002 Zn II 0.06 Ga n 0.05 Ge t " .81 0.01 Sr II 0.01 Mb 11 0.08 Ru n 0.02 Rh 11 0.03 Ag « 0.0002 sn H 0.01 Sb II ■ 0.03 Te « 0 .10 Ta It 1.0 It Re 0 . 07 Pt 81 0.01 Tl 11 0.80 Pb » 0.08 Bi If 0.002 U 81 0.30 195

PHK-12c-72: Molybdenite, New Year's Eve breccia pipe, 3760 ft bench, Esperanza pit, Sierrita Moun tains, Sahuarita, Pima County, Arizona, 31°51 '• 59" N, 110°07 1 32" W. Molybdenite pods are intergrown with pink orthoclase, black - rutile, and milky quartz. The quartz has in- - elusions of pyrite. Some specimens have con- ■ siderable muscovite„ The host rock is a quartz monzonite breccia, Se was not determined.

Split #1 Split #2 Split #1 : Split #2

Mo : 56.3 % 56.0 % MoS2 93.9 % ‘ 93.4 % Mg 0.0080 0.0085 MgO . 0.013 0.014 Al 0.037 0.046 a 12°3 0.070 0.087 si 1.9 . 2.0 Si02 4.i v 4.3 Ca 0.0032 0.0037 . CaO 0.0045 0.0052 Ti V 0.18 0.15 Ti02 V: 0.30 i 0.25 V 0.0048 nd< 0.004 v 2o 5 0.0086 Cr 0.0070 0.0040 Cr 20 3 0.010 ; 0.0058 Fe v 0.39 0.18 FeS2 0.84 0.39 Cu 0.0058 0.0067 CuS V 0.0087 . 0.010

Total 99.3 % 98.5 % B - nd< 0.007 Na H 0.10 K 51 0.30 Mn H 0.003 Zn VI 0.06 Ga. VI 0.05 Ge II 0.01 Sr » ‘ > 0.01 Nb II 0.08 Ru IV 0.02 Rh VI • 0.03 Ag VI 0.0002 Sn 11 0.01 Sb II 0.03 Te VI 0.10 Ta 81 1.0 W 11 0.10 Re 81 0.07 Pt 18 0.01 Tl SI 0.80 Pb 81 0.08 Bi VI 0.002 u VI 0.30 196

PHIv-8-75: Molybdenite, quartz vein near Cleator, Turkey Creek, Bradshaw Mountains, Prescott National Forest, Yavapai County, Arizona. 34°16144" N, : 112013'56" W. Hexagonal books, 8 mm wide, of molybdenite were found in milky quartz. Some of the quartz also contained a few 3 mm wide • pods of a velvety, bright yellow mineral. Se was not determined. .

Mo 58.0 % : MoS2 96.8 %

Mg 0.0015 MgO 0.0025 Si ' 0.90 Si02 1.9 Ca trc0.0004 CaO 0.0006 Ti 0.0066 Ti02 0.011 Fe 0.059 FeS2 0.13. Cu 0.0015 CuS ' 0.0023 Ag ; 0.0015 Ag^S . - 0.0017

Total 98.8 b . ndc 0. 007 Na ii -0.10 Al. ii 0.004 K - ii 0.30 v; : n 0.004 Cr it 0.002 Mn . ii 0.003 Zn H 0.06 Ga it 0.05 Ge ii 0.01 Sr ii 0.01 Nb ii 0.08 Ru ii 0.02 Rh ii 0.03 Sn it ! 0 .01 Sb ii 0.03 Te n 0.10 Ta . ii 1.0 w ii 0.10 Re ii 0.07 Pt ii 0.01 : Tl H . 0.80 Pb ii . 0.08 Bi •I 0.002 U ii 0.30 197

PHK-9-75: Molybdenite, Garnet Hill, 1 km south, of the Mokelumne River, near Moore Creek, Calaveras County, California. 38°28'46" N, 120°15,10" W. The sample was taken from a 3.5 cm wide molyb denite book intergrown with epidote and quartz. The dark green epidote crystals range in length . from 1 to 250 mm. The. molybdenite occurs in a tactite with scheelite, chalcopyrite, pyrite, and bornite (Clark and Lydon, 1962). Se was not determined..

MO 57.1 % MoS2 ' 95.3 %

Mg... 0.0095 MgO 0.016 Si 1.6 Si02 3.4 Ca 0.0020 . CaO 0.0028 Ti tr< 0.002, TiC>2 . tr< 0.003 . Mn tr< 0.003 : MnS tr< 0.005 Fe 0.067 FeS'2 .' ' 0.14 W tr< 0.10 W S 2 . trc 0.13 .

Total 99.0 " % B n d < 0 . 0 0 7 V N a 0 . 1 0 . .'u ■■ A l 0 . 0 0 4 n K . 0 . 3 0

V 11 0 . 0 0 4

C r 0 . 0 0 2 « C u 0 . 0 0 0 2 n Z n 0 . 0 6 n G a ' 0 . 0 5

G e 0 . 0 1 18 S r 0 . 0 1 W N b 0 . 0 8 11 R u 0 . 0 2 M R h 0 . 0 3 If A g v 0 . 0 0 0 2 » S n 0 . 0 1 . If ■ S b 0 . 0 3 11 T e 0 . 1 0 If T a 1 . 0 11 R e 0 . 0 7 ii; • P t 0 . 0 1 ti. T l 0 . 8 0 . 11 P b 0 . 0 8 • •II..' B i 0 . 0 0 2 ti U 0 . 3 0 198

PHK^-10-75: Molybdenite, Tanyang district t along the Han Riverr 10Q km northeast of Taejon, Ch1ungch1ong- Pukto Province, South Korea. 36°56* n, 128°19' E. The sample was taken from a 3.5 x 2.5 x - 2.0 cm book of molybdenite. Se was not deter mined.

Mo 59.0 % MoS 2 98.4

Mg 0.0015 MgO 0.0025 Si 0.16 Si02 0.34 Ca tr<0.0004 CaO t# 0.0006 Fe 0.046 FeS2 , . 0.099 Cu 0.0018 CuS 0.0027 Ag 0.0058 Ag2S 0.0067 W tK 0.10 WS2 tKO.13 Pb 0.45 PbS 0.52 Bi 0.40 Bi2S3 0.49

Total 100.0 B . . . nek 0.007 Na n 0.10 n A1 0.004 K V 0.30 Ti v . n ' 0.002 V it 0.004 Cr « 0.002 Mn «i 0,003 Zn : " - 0.06 Ga 11 0.05 tl Gb 0.01 Sr 11 0.01 Nb ' 11 0.08 Ru 11 0.02 Rh 11 0.03 Sn 11 0.01 Sb II 0.03 Te 11 0.10 Ta It 1,0 Re 11 0.07 Pt tl 0.01 Tl II 0.80 U 11 0.30 199

PHK-KL1--75 : Molybdenite, Tae Hwa mine, Nungam-ni7 Ch’ungch1 ong-Pukto Province, South Korea. (The lati tude and longitude are unavailable.) The sample was taken from a 2 x 2 x 2 cm twinned book of molybdenite that had inclusions of quartz. Se was not determined.

Mo 59.0 MoS. 98.4

Mg 0. 0014 MgO 0.0023 Al tr< 0. 00 4 A I 2O 3 tr< 0.008 Si 0.38 Si02 0.81 Ca 0.029 CaO 0.041 Fe 0.061 FeSp " 0.13 Cu 0.0019 CUS 0.0029 Ag tr< 0.0002 Ag 2S tr< 0/0002 Pb 0.16 PbS . 0.18 Bi 0.077 . 0,095: Bi2B 3 ;

Total 99.7 B ndc 0.007 Na « 0.10 K ti 0.30 Ti w 0.002 V n 0.004 Cr 11 0.002 Mn 11 0.003 Zn •1 0.06 Ga 11 . 0.05 Ge ii 0.01 Sr u 0.01 Nb 11 0.08 Ru 11 0.02 Rh •• 0.03 Sn 11 0.01 Sb ti 0,03 Te 11 0.10 Ta 11 1.0 Re 11 0.07 Pt it 0.01 Tl " 0.80 : U 11 0.30 2 00

PHK-'12r-.75: Molybdenite, Tae Hwa mine, Nungam-ni, Ch'ungch' ong-Pukto Province, South Korea. (The latitude and longitude are unavailable.) The sample was taken from a 3.5 x 3.0 x 1.5 cm book of molyb denite that -was shaped like an open clam shell and.filled with quartz. Se was not determined.

m o ; 56.8 MoS2 . 94.8

Mg : 0.0063 MgO" 0.010 A1 0. tr< 0.004 A I 2O3 trc 0. 008 Si 1.7 Si02 3.6 Ca 0.025 CaO 0.035 Fe 0.059 FeS2 0.13 Cu 0.0022 CuS 0.0033

Total 98.6 B nek 0.007 Na 11 0.10 K 11 0.30 Ti 11 01002 V 11 0.004 Cr n 0.002 Mn " . 0.003 Zn 11 0 . 06 Ga « 0.05 tie. II 0 .0.1 Sr n 0.01 Nb 11 0.08 Ru 11. 0.02 Rh 11 0.03 Ag II 0.0002 Sn 11 0.01 Sb 11 0.03 Te II 0.10 Ta II 1.0 W 11 0.10 Re .. 11 0.07 Pt 11 0.01 • Tl II 0.80 Pb 11 0.08 Bi II 0.002 U it 0.30 201

PHK-14--75: Molybdenite, Tae Hwa mine, Nungam-ni, Ch1 un-gob.' ong-Pukto Province, South Korea. (The latitude and longitude are unavailable.) The sample was - taken from a 4 x. 4 x 3 cm book of molybdenite that had a few inclusions of quartz and chalcopyrite. Se was not determined.

Mo 57.4 Mo S . 95.8

Mg 0.0059 MgO 0.0098 Al 0.020 0.038 Si 1.3 Si02 2.8 Ca 0.0067 . CaO 0.0094 Fe 0.047 FeS 2 0.10 Cu 0.00046 CuS 0.00069 Ag 0.0038 AgoS 0.0044 Pb 0.30 . PbS 0.35 Bi 0.058 0.067 B12S3

Total . 99.2 B ncfc 0.007 Na , 81 0.10 K . It 0.30 Ti » 0.002 V n • , 0.004 Cr, IX 0.002 Mn 81 . 0.003 Zn " 0.06 ■ Ga - : n 0.05 Ge 81 0.01 Sr 11 0.01 Nb If 0.08 Ru 11 0.02 Rh 81 0.03 Sn It 0.01 Sb 11 0.03 Te 81 0.10 Ta 81 1.0 w .11 0.10 Re " 0.07 Pt 81 0.01 T l II 0.80 U 11 0.30 202

PHK-41--75: Molybdenite, mine dumps near the Mohawk shaft, Helvetia, northwestern edge of the Santa Rita Mountains, Pima.County, Arizona. 3105il33" N, 110°46'56" W. Molybdenite rosettes and blebs occur in 3 mm wide quartz veinlets that cut orangish—brown garnet. Minor chalcopyrite and traces of powellite are in the garnet. Se was not determined.

Mo 56.0 % MoS2 93.4 %

Mg 0.072 MgO 0.12 a i ; ..... 0.044 AI2O3 0.083 Si 1.9 Si02 4.1 . Ca . 0.067 CaO 0.094 Mn 0.044 MnS 0,0.70 Fe. 0.28 FeS2 0.60 Cu 0.0019 CuS : 0.0029 Pb 0.37 PbS 0.43

Total 98.9 B nd< 0.007 Na 0.10 K H 0.30 Ti U 0.002 V « " 0 . 004 C r . n 0.002 Zn ■. 81 • 0.06 G& ti 0.05 Ge •18 0.01 Sr 81 0.01 Nb 81 0.08 Ru » 0.02 Rh 81 0.03 Ag 11 0.0002 Sn 88 0.01 Sb 88 ■ 0.03 Te 81 0.10 : Ta . 88 1.0 81 W , 0.10 Re 81 0.07 Pt 11. 0.01 Tl 81 0.80 Bi 81 0.002 U 81 0. 30 . 203

PHK-1-76: Molybdenite, Bagdad pit , N1500, W3350, elevation 3098 ft, Bagdad-Cyprus property, Bagdad, Yavapai County-, Arizona. 34°351120" N, 1:13° 10'31" W. Molybdenite selvages, were found along the edges of 1 cm wide quartz veinlets in al tered granodiorite. Molybdenite, pyrite, and chalcopyrite are disseminated in the- altered granodiorite. Se was not determined.

Mo • 53.2 % MoS2 88.8, %

Mg 0.047 MgO .0.078 A1 0.86 Al203 1.6 Si 3.1 Si02 6.6 Ca 0.012 CaO : 0.017 Fe ' 0.19 FeS9 0.41 Cu - 0.071 CuS 0.11 Sr tK 0.01 SrO trcO.Ol Ru tr< 0.02 . RuS2 tr< 0.03 Ag tr< 0.0002 Ag2S tr< 0.0002

Total; 97,7 B nd< 0.007 Na » 0.10 K - " 0.30 ■Ti tl 0 .002 V n 0.004 Cr . u 0.002 Mn ■ ti 0.003 Zn tt 0.06: G a n 0.05 Ge i t. - 0.01 Nb u 0.08 Rh it 0.03 Sn ii 0.01 Sb « 0.03 - Te it 0.10 Ta . ii 1.0 W - » '/ 0.10 Re II 0.07 II Pt . 0.01 Tl , II 0.80 Pb l.l 0.08 Bi tl 0.002 U If 0.30 204

PHK-21-76: Molybdenite, dacite porphyry dike, 2015 ft level, San Manuel mine. Magma- Copper Corp., Black Hills, Pinal County, Arizona. 32°41146“ N, 110°41* 23" W. A 1.3 cm wide quartz-molyb- . denite veinlet cuts a dacite porphyry dike, and is cut in turn by a chalcopyrite-guartz- kaolinite—cemented fracture. The dacite porphyry dike contains finely disseminated chalcopyrite and microveinlets of chalcopyrite. Se was not determined.

Mo - 45.5 % M o S2- •• 75.9

Mg 0.066 MgO 0.11 A1 0.43 A1203 0.81 Si 6.9 Si02 14.8 Ca 2.4 CaO 3.4 Ti 0.20 Tio2 0.33 V 0.0044 v 2;o5 ; 0.0079 Cr 0.0033 Cr2°3 0.0048 ,Mn - 0.025 MnS 0.040 Fe ' - . 0.98 ' FeS2 ... 2.1 . Cu 0.018 CuS 0.027 Sr . t n 0.01 SrO trc 0.01 Ag 0.0020 Ag2S ; : 0.0023 Re 0.10 ReS? 0.13 Pb 0.29 PbS 0.33

Total 98.0 B nd< 0.007 Na • " '• ■0.10 : ii : K . 0.30 Zn ii 0.06 Ga ii 0.05 Ge u 0.01 Nb ii 0.08 Ru it 0.02 Rh 81 0.03 Sn ii 0.01 Sb ii 0.03 Te 81 0.10 Ta ii 1.0 W ii 0.10 Pt ti 0.01 Tl ll 0.80 Bi ii 0.002 if U 0.30 205

PH.Kr-38b-76: Molybdenite, center of the. East pit, ANAMAX Twin Buttes' mine, eastern pediment of the Sierrita Mountains, Sahuarita, Pima County, . Arizona. 31°53'38" N, 111°01'56K W. Fine flakes of molybdenite up. to 2 mm in diameter are disseminated in tan to brown garnet. Microveinlets of pyrite, 0.5 mm wide, also cut the garnet. Crystals of quartz less than 0.5 . mm in length fill vugs about 6 mm in diameter. Se was not determined.

Split #1 • Split #2 Split #1 Split

Mo - 45.0 % ■ 45.0 % ; M0 S2 75.1 % 75.1 Mg 0.054 . 0.053 MgO 0.090 0.088 A1 0.031 0.049 :: AI2O 3 0.059 0.093 Si 5.9 5.9 Si02 12.6 12.6 Ca 3.2 3.0 . CaO 4.5 4.2 : Mn - 0.042 : 0.039 ' MnS 0.067 0 .062 Fe 0.77 0.90 FeS2 1.7 1.9 Cu 2 .4 . 2.3 CuS 3.6 3.5 Zn. 0.11 : tri 0.06 ZnS 0.16 . trc 0 . 09 Sr nd< 0 .01 t K 0.01 SrO tr< 0.01 : Ru hd< 0.02 0.029 RUS2 0.047 Ag. 0.0013 0.0013 ■ . A g 9S 0.0015 0.001

Total 97.9 % . . 97.7 % B nd< 0.007 Na " 0.10 K H 0.30 Ti,• « 0.002 V 11 0.004 Cr 11 0.002 Nb H. . 0.08 Eh 11 0.03 Sn 11 0.01 Sb n ■ 0.03 Te u 0.10 Ta 11 1.0 ,. W « 0.10 ; Re if 0.07 Pt 11 0 . 01 Tl n 0,80 Pb if. , ... 0.08 Bi 11 0.002 U 11 0.30 206

PHK-38c-76: Molybdenite, center of the East pit, AMAMAX Twin Buttes mine, eastern pediment of.the S.ierrita Mountains, Sahuarita, Pima County, Arizona. 31°53'38u N, 111°01'56" W. Fine flakes of molybdenite up to 2 mm in diameter are disseminated in tan to brown garnet.■ Microveinlets of pyrite, 0.5 mm wide, also cut the garnet. Crystals of quartz less than 0.5 mm in length fill vugs about 6 mm in diameter. Se was not determined.

Mo ; 52.4 % . MoS2 : 87.4 =

Mg • 0.033 MgO ' 0.055 A1 . 0.030 AI-2O3 0.057 Si 4.3 SiO2 9.2 Ca 0.32 CaO - 0.45 Mn 0.019 MnS 0.030 Fe 1.2 FeS2 2.6 Cu 0.77 CuS 1.2

Total 101.0

B ndc 0.007 Na II 0 .10 K If 0.30 Ti II 0.002 V II 0.004 . Cr II 0.002 Zn II 0.06 Ga II 0.05 Ge II 0.01 Sr H 0.01 Nb II • . 0.08 Ru If 0.02 Rh II 0.03 Ag « 0.0002 Sn • V ■ 0.01 Sb II 0.03 Te 11 0.10 Ta I t 1.0 W I t 0.10 Re 11 0.07 Pt " II ■:0.01 Tl It 0.80 Pb • II 0.08 Bi If 0.002 U - 81 0.30 207

PHK.^.39-76 Molybdenite., Leader mine, Helvetia, northwestern edge of the Santa Rita'Mountains, Pima County, Arizona. 31°51,-35,! N, 110°46,10" W. Molyb denite pods up to 1.5 cm in diameter occur in milky quartz. The quartz has minor iron staining. Se was not determined.

Mo 47.0 MoS2 78.4 %

Mg. 0.0042 MgO 0.0070 A1 0.036 AI2O3 0.068 Si 9.9 Si02 21. 2 Ca 0.0091 CaO 0.013 Fe 0.065 FeS2 ■ ■ . 0.14; Cu 0.0055 CuS 0.0083

Total : ' 99.8 B . : nd< 0 . 007 Na M 0.10 K 81 0.30 Ti 11 0.002 V t l 0.004 Cr 11 0.002 Mn » • 0.003 Zn 11 0 .06 Ga 11 0.05 Ge n 0.01 Sr M 0.01 Nb U 0.08 Ru 11 0.02 Rh . 18 0.03 Ag 11 0.0002 Sn 11. 0.01 Sb 11 0.03 Te 1.1 ■ 0.10 Ta 11 1.0 W 11 0.10 Re 11 0.07 Pt 81 0.01 Tl « 0.80 Pb 11 ' 0.08 Bi « . 0.002 U IF 0.30 2:08

PHK-'42t76 : Molybdenite, sample supposedly collected from a quartz vein, at Bisbee, Cochise County, Arizona. 31°261 N, 110o54l- W. The sample was taken from a molybdenite pod in milky quartz. The. quartz • also contained minor pyrite. Se was not de termined. .;

Mo 50.8 % MoS2 84.8

Mg : 0.0062 MgO 0.010 A1 . 0.058 • AI2O3 .v 0.11 Si 3.8 Si02 8.1 Ca 0.0065 CaO 0.0091 Ti 0.0089 . Ti02 0.015 Fe . 0.78 FeS2 . . 1.7 Cu 2.1 CuS 3.2

Total 97.9 :: % B hd< 0.007 Na \ H 0.10 K « . 0.30 V. n 0 . 004 Or « 0.002 Mn ' « 0.003 Zn n 0 . 06 Ga 11 0.05 Ge 11 0 . 01 . Sr 11 0.01 Mb ' 11 0.08 Ru n 0.02 . Rh . n 0.03 Ag ii 0.0002 Sn 11 • 0.01 Sb it 0.03 Te ii 0.10 Ta ii 1.0 W ' ii 0.10 Re H 0.07 Pt II 0.01 Tl " 0.80 Pb tl 0.08 Bi II 0.002 ll : . II 0.30 209

PHK-r45--76 : MolybdeniteNew Cornelia pit., Phelps Dodge Corp., Little Ajo Mountains, Ajo, Pima County, Arizona. 32°21'25" N, 112°52,01" W. Flakes of molybdenite, 8 mm in diameter, occur with - chalcopyrite in a.matrix of pink orthoclase crystals up to 1.5 cm in length. Se was not determined.

Mo ' 57.5 % . . M o S2' ; . 95.9

Mg 0.0094 MgO 0.016 A1 0.038 AI2O3 0.072 Si 0.60 SiOg 1.3 Ca 0.014 CaO 0.020 Fe . 0.83 • . FeSg 1.8 Cu 0.68 CuS 1.0

Total 100.1 B n&c 0.007 Na ■ if . 0.10 K U 0.30 Ti 11. 0.002 V 11 0.004 Cr 11 0.002

Mn . ” :0.003 Zn 11 0 . 06 Ga ■ 11 ■ 0.05 Ge 0.01 Sr . ' « _ 0.01 Mb « 0.08 Ru it 0.02 Rh tt 0.03 Ag H. 0.0002 Sn n 0.01 Sb ■it 0.03 Te ■81 0.10 Ta n 1.0 W « 0.10 Re n 0.07 Pt V 0.01 Tl it 0.80 Pb 11 0.08 Bi . it 0.002 U tt 0.30 210

PHK-18-77: Molybdeniteeast wall of the East pit, ANAMAX. Twin Buttes mine, eastern pediment of the ■ Sierrita -Mountains, Sahuarita, Pima County, Arizona. 31°53'38" N, 111°01,56" W. Molyb denite rosettes, up to 10 mm in diameter, are intergrown with chalcopyrite., anhydrite, and traces of molybdian scheelite. The anhydrite contains pyrite cubes ranging in size from 1 to 8 mm. Some of the molybdenite has inclusions, of chalcopyrite. Se was not determined.

Mo '. 56.0 % MoS2 93.4

B 0.016 B2O 3 .. 0.052 . Mg . 0.042 ' MgO '. 0.070 A1 : 0.025 AI2O3 0.047 Si . 0.59 -SiO'2 1.3 Ca . 0.13 CaO 0.18 Mn ; 0.0094 . MnS ■ 0.015 . Fe 1.6 FeS2 3.4 Cu ■ ..’ 1,7 . ■ . CuS . 2.6 Ag 0.0034 Ag2S 0.0039 Pb 0.23 , . PbS 0.27 .

Total 101.3 Na " nd< 0 . 10 K II 0.30 Ti II 0.002 V If 0.0:04 Cr » 0.002 Zn ft 0.06 Ga II 0 .05 Ge » 0.01 Sr 11 0.01 Nb n 0.08 Ru if 0.02 Rh n 0.03 Sn it 0.01 - „ Sb 0.03 Te . 11 0.10 Ta . . 11. 1.0 W it 0.10 Re it 0.07 Pt • . " 0.. 01 Tl ft 0.40 Bi 11 0.002 U 11 0.30 211

UAKA 74-184 : - Molybdenite, Mina las Higueras, Pericos district. State of Sinaloa, Republic.of Mexico. 25°00 1 39" N, 107°13I-45U W. . The molyb- ■ denite is disseminated with chalcopyrite py- : rite, and sericite in hydrothermally al tered granodiorite. Se was not determined.

Mo 57.4 % MoS ' 95.8 2 Mg . 0.0085 MgO 0.014 A1 0.47 A I 2O 3 . 0.89 Si 1.3 Si02 ■. 2.8 Ca../ 0.035 GaO . 0.049 Fe 0.12 FeS2 0.26 Cu 0.0072 CuS 0.011 Pb 0.14 PbS . 0.16

Total 100.0 B n

PED-57--66 : Molybdenite, Mina la Guadalupe, Nacozari , State of Sonora, Republic of. Mexico. 30°18 118” N, ... 10 9°34 ‘ 12" W. The .molybdenite occurs in a pegmatite with biotite, feldspar, chalcopyrite, . pyrite, apatite, and quartz. Se was not de- .termined.

Mo 58.8 % MoS2 98.1

Mg 0.023 MgO 0.038 A1 0.035 AI 2O 3 0.066 Si " 0.54. Si02 1.2 Ca 0.0051 CaO 0.0071 Fe 0.13 FeS2 0.28 Cu 0.067 CuS 0.10

Total 99.8 B h * 0.007" Na n 0.10 R: 11 0.30 Ti 11 0.002 V if 0.004 Cr 11 0.002 Mn ' 11 0.003 Zn 11 0.06 Ga 0 . 05 : Ge 11 0.01 Sr 11 0.01 Nb " 0.08 Ru ii 0.02 . Rh 11 0.03 Ag •; 11 0 .0002: Sn 11 0.01 Sb 11 0.03 Te 11 0.10 Ta . ti 1.0 W « 0.10 Re 11 0.07 Pt ii ■ , 0.01 Tl ; 11 0.80 Pb H 0.08 - Bi 91 0.002 U .. 81 ‘ 0.30 APPENDIX D

EMISSION SPECTROGRAPHIC ANALYSES OF FERBERITE, WOLFRAMITE, AND HUEBNERITE

The analyses were made by Hal W. Johnson, Pacific

Spectrochemical Laboratory, Los Angeles, California.

213 214

PHK--02-r69 : Wolframite, pegmatitic vein in monzonite por phyry , 1475 ft haulage level., San Manuel mine. Magma Copper Co., Black Hills, Pinal County, Arizona. .32041 ,4'6U N, 110°41l 23" W. . Black wolframite pods were found intergrown with pyrite and quartz crystals in a pegmatitic vein within the Laramide monzonite porphyry.

Split #1 Split -#2 Split #1 Split #2

Mh 3.8 % 2.7 % MnO 4.9 % 3.5 % Fe 14.5 10.7 - FeO - - ■ 18.7 13.8 W 60.2 64.8 w°3 ; 75.9 81.7

Mg. 0.025 0.031 MgO ■ . 0.041 ' 0.051 A1 0.074 0.055 AI2O3 0.14 0.10 Si 0.24 0.20 Si02 0.51 0.43 Sc 0.044 0.032 SC2O3 0.067 0.049 Ti 0.043 0.051 Ti02 0.072 0.085 0.011 0.014 Sn 0.059 Sn02 0.075

Total 100.3 % 99.8 % K nek 0.10 ca H 0.0004 V . » 0.006 Cu it 0.0004 Zn II. 0.03 Ge ti 0.003 ...... Y II 0.002 Nb 11 0.03 Mo It 0.008 In H 0.01 La at 0.002 Ta BI 0.20 215

PHK--30-69 : Ferberitez Ventura-breccia pipe, . Cox Gulch, west central part of the Patagonia Mountains, Santa : ' Cruz County, Arizona. 31°271:41" N, 110o46, 06" W. The samples; were collected from a 12 Cm wide black-brown ferberite pod in the vuggy quartz zone of a molybdenite-chalcopyrite-rich breccia pipe. The breccia pipe cuts altered Jurassic (?) Comoro Canyon Granite,

. Sample #1 ■ ■ ' Sample #2, Sample #1 Sample #2

Mn : 4.55 % ... 3.0 % MnG 5.88 % 3.9: % Fe 14.7 12.9 FeO ^ 18.9 . 16.6 W ' 56,5 63.0 W03 71.3 - 79.4 -

Mg 2.2 0.041 , MgO 3.6 0.068 Al ' 0.017 0.037 : AloOo 0.032 0.070 Si 0.035 0.071 SiOg ; 01075. . 0.15 Ca 0.0049 0.012 CaO I 0.0069; 0.017 Sc . 0.079 0.012 Sc2Q 3 0.12 0.018 Ti . 0.043 0.022 Tid2 0 . 072:0. 037 Ta . 0.50 : , nd; 0.20 Ta2Og 0.61 —— .

Na nd< 0.06 Total 100.6 % 100.3 % K ir 0.10 V if 0.006 Ni if 0.003 CU if 0.0004 Zh ...II . y 0:103 Ge VI 0.003 Y , H 0.002 Nb « 0.03 Mo II 0,008 Ag II 0.0008 in II 0.10 . sn II 0.009 La II 0.002 Ce El 0.04 Sm 11 0.03 Gd II 0.05 Yb . 11 ; 0.004 ,216

PHK-39^69: Huehnerite, quartz vein in the Schultze Granite (quartz inonzonite) prospect, Pinal Ranch, 0.3 km north of Highway 60/70, Pinal County, Arizona. 330 21'10" N, 110°59l23" W. Red-brown huehnerite crystals were found, with pyrite and feldspar in a quartz vein cutting the Schultze Granite (quartz monzonite). The vein is near the contact of the stock with the Precambrian . Pinal Schist.

Mn ■ - ' ' . 17.6 % MnO 22.7 % Fe 3.90 FeO ' 5.02 W : 56.5 71.3 . W 0 3 Mg 0.058 MgO 0.096 Al ' 0.063 AI 2O 3 0.12 Si 0.13 . Si0 2 : 0.28 Ca 0.37 CaO ■ . 0.52 Sc 0.0066 SC2O3 v. 0.010 . Ti 0.015 Tio2 0.025 Cu . 0.010 CuO " 0.013 Zn 0.047 ZnO 0.059 Y tr 0.002 . y 2o 3 •tr 0.003 Ce 0.097 Ce203 0 .11 Yb 0.024 Yb203 0.027

Total 100.3 % Na nd< 0 . 06 K " 0.10 : V M 0.006 Ni II 0.003 Ge If 0.003 Nb II 0.03 MO $1 0.008 Ag II 0.0008 In u • 0.10 Sn ei 0.009 La 11 0.002 Sm . 11 0.03 Gd • » 0.05 Ta it 0.20 217

PHK-6-71: Huebnerite, Little Fanny claims. Sheep Basin, Little Dragoon Mountains, Cochise County, Arizona. 32o03,23" N, HO L D S ' 52" w. . Red-brown stringers of huebnerite were.collected from a : N 45° E trending quartz vein in the Texas Canyon , Quartz Monzonite. The quartz also contains minor galena, yellow to brown-black, sphalerite, chalcopyrite, and muscovite. Part of the chalcopyrite and sphalerite is coated with covellite.

Mn 18.5 % . • I4n0 23.9 Pe : 0. 6 3 ' FeO . ■ 0 . 81 W 59.5 W03 . 75.0

Mg 0.0 33 MgO 0.055 A1 0.019 AI2O 3 0.036 Si 0.10 Si02 0.21 Ca 0.011 CaO • 0.015 Sc 0.0011 SC2O3 0.0017 Ti 0.0051 . Ti02 0.0085 Cu 0.0023 CuO 0.0029 Zn ... 0.0631 , ZnO 0.078 Y tr< 0.002 Y 2O 3 tr< 0.003 Nb tr< 0.03 Nb 205 tr< 0.04 Ce _ 0.091 Ce203 0.11 Yb . 0.016 Yb203 0.018

Total 100.3 % Na : nd< 0.06 K " 0.10 V " 0.006 Ni " 0.003 Ge " 0.003 Mo . " 0.008 Ag " 0.0008 In 7 " 0.10 Sn " 0.009 La " 0.002 Sm " 0.03 Gd " 0.05 Ta " 0.20 218

PEEK-2 4-71: Huebnerite , General Electric XI. mine Las Guijas Mountains, Ariyaca Quadrangle, Pima : County, Arizona. 31:039 '■ 25. 5n N r’ 111°22 * 44. 5" . W. Huebnerite and wolframite are associated with minor sphalerite and chalcopyrite in milky quartz veins. The quartz veins accompany sulfide-rich andesitic dikes that cut the alaskite stock.

Mn. 21.4 % MnO 27.6 Fe ■ ' 2.29 FeO '■ 2.94 W 53.8 W0 3 . 67.8

Mg 0.049 MgO 0.081 A1 0 a 17. ... AI2O3 - 0.32 Si 0.47 Si02 1.0 Ca 0.028 CaO 0.028 Sc : • 0.028 • SC2O3 . 0.043 Ti ' 0.011 Ti02 0.018 Cu 0.0041 CuO 0.0051 Zn . tr< 0.03 ZnO ; tr< 0. 04 Nb 0.090 N b 205 0.13 Ce tr< 0.04 Ce203 tr< 0. 05

Total 100.1 % •Na . . nd< 0.06 K II 0.10 V 0.006 Ni II . 0.003 Gb « 0.003 Y 0.002 Mo ■ 11 0 . 008 Ag II 0.0008 In . It 0.10 Sn " 0.009 La « 0.002 Sm 11 0.03 Gd II 0.05 Yb . If- ; 0. 004 Ta II 0.20 ..219

PHK-17-72: Wolframite, Kaneuchi mine, Kyoto Prefecture, Kinki district, Japan„ 35 15' N, 135°30' E. (The exact latitude and longitude were unavail^- able.) Brown-black wolframite crystals up to - 5 cm in length occur in milky quartz with minor, . chalcopyrite and scheelite. The scheelite forms haloes around the wolframite„ The ore deposits have formed in roof sedimentary rocks of Paleo zoic age, and are related to the intrusion of a granodiorite Stock„ Vein muscovite from the ' mine gave a K-Ar age of 91.2 m.y„ (Shibata and Ishihara, 1974).

M n y 5.70 MnO . . 7. 36 Fe 6.25 Feo 8.04 w ^ 66.5 WO- 83.9 3 Mg 0.093 MgO 0.15 Al 0.027 AlgOg : 0.051 Si 0.071 Si02 0.15 Ca 0.015 CaO 0.021 Ti 0.015 Ti02 0.025 Cu 0.0020 CuO 0.0025

Total 99.7 . % Na nd< 0.06 K II 0.10 Sc II 0.001 v II 0.006 Ni . II 0.003 Zn - It 0.03 Ge ^ ■ 0.003 Y II 0.002 Nb II 0.03 Mo It 0.008 Ag II 0.0008 In II 0.10 Sn II 0.009 La ■ ■ . 0.002 Ce II 0.04 Sm II 0.03 Gd II 0.05 Yb • II 0.004 Ta II 0.20 220

PHK,^2--75.: Huebnerite, Mina, northeastern end of the Ex celsior Mountains, Mineral County, Nevada. 38°22130" N, 118°07130" w. (The exact latitude and longitude were unavailable.) The red-black huebnerite is associated with rhodochrosite, pyrite, and.traces of galena in quartz. The milky quartz contains numerous small cavities lined with 1 iron long quartz crystals.

Mn 14.8 % ' MnO 19.1 S Fe ' 0.34 . FeO ■ 0.44 W 62.8 WO-- 79.2 . - -> Mg 0.030 MgO 0.050 A1 0.018 v AI2O3 0.034 Si 0.35 Si02 0.75 Ca 0.015 CaO 0.021 Sc ;v 0.0021 : . SC2O3 0.0032 Ti . ' 0.043 Ti02 . 0.072 Cu 0.0024 CuO 0.0030 Zn . tr< 0.03 ZnO trc 0.04 . Nb 0.092 Nb2G5 ' 0.13 Ag 0.0092 AgyO 0.0099 Ce 0.10 Ce203 0.12

Total 100.0' ' % Na . nd> 0.06 K u 0.10 V n 0.006 Ni , « 0.003 Ge 11 0.003 Y 11 0.002 Mo 11 0.008 In 11 0.10 Sn 11 0.009 La 11 0.002 Sm n 0.03 Gd 11 0 .05 Yb 11 0.004 Ta : " 0.20 221

PHK-3-75: Ferberite, Panasqueira mines, Beralt Tin and Wolfram, Ltd., northwestern side of the Rio Zezere, 40 km northwest of Castelo Branco, Beira Baixa, central Portugal.. 40°09 'SO" N, 0/44 ’ 05" W. Masses of black wolframite occur with arsenopyrite, yellow to green-•gray muscovite, .. and traces of chalcopyrite in in vein quartz..

Mn • 2.2 % MnO 2.8 % Fe. 10.0 FeQ - 12.9 . W 66.3 . 83.6 . W0 3 Mg 0.016 MgO 0.027 Al : 0.097 AI2O3 0 .18 Si 0.056 sio2 0.12 Sc 0.0062 SC2O3 0.0095 Ti 0.010 . Ti02 0.017

Total 99.7 % K . nd< 0.10 Ca " 0.0004 V " 0.006 Cu " 0.0004 Zn " 0.03 Ge . " 0.003 Y " 0.002 Nb " 0.03 Mo " 0.008 : In " 0.01 Sn " 0.009 La . "0.002 Ta . ” 0.20 222

PEEK-4-75 : Ferberite, Panasqueira mines, Bexalt Tin and Wolfram, Ltd., northwestern aide of the Rio Zezere, .40 km northwest.of Castelo Branco, Beira B.aixa, central Portugal. 4 0°09 1 30 " N , 0 7°44105" W. Brown-black crystals of ferberite up to 2 cm in length are intergrown with musco- • vite in vein quartz«

Mn. 1.84 % MnO ' 2.3 8 .% ' Fe 12.7 FeO 16.3 . :W ■ •, 64.0 ■ W O 2 .; 80.7

Mg 0.034 MgO . 0.056 Si 0.019 Si02 . 0.041- Ti 0.013 Ti02 0.022 . Ta . 0 b 38 Ta^Og ■ ; 0.46

Total 100.0 Na nd< 0.06 A1 11 0.005 K ; 11- , 0.10 Ca ■■ If -0.0004 ... it Sc .. 0.001 V ' 0.006 Ni is. 0.003 , Cu ., 11 0.0004 Zn II 0.03 Ge ; 11 0.003 Y ii 0.002 Nb si 0.03 Mo ■ if 0.008 Ag ii 0 . 000 8 In ii 0.10 Sn ii 0.009 La " ii 0.002 Ge H 0.04 Sm h 0.03 Gd 11 0.05 Yb . if 0.004 Ta ii 0.20 223

PHK-^5^-75: Ferberite r Panasqueira mines. Bar alt Tin and Wolfram, Ltd., northwestern side of the Rio Zezere, 40 km northwest of Castelo Branco, Beira Baixa, central Portugal. 40 09'30" N, : . 07°44105” W. The sample was taken from a 5 x 3 x 2 cm brown-black ferberite crystal that was coated with muscovite, 1 mm tall green-gray apatite crystals, and limonite. •

Mn 0.69 % '.MnO 0.89 ! Fe . 9.8 FeO 12.6 W ■ 67,5:'.". W03 85.1

Mg: - 0.047 ' MgO 0.078 A1 ' 0.072 AI2O3 0.14 Si 0.043 SiC>2 0.092 Ti 0.013 Ti02 0.022 Cu 0.0018 CuO . 0.0023 Ta 0.32 Ta 05 0.39

Total 99.3 Na nd< 0. 06 . K ' ■ • ». ■ OilO Ca 11 0.0004 Sc 11 0.001 V II, 0.006 Hi » 0.003 Zn . It 0.03 Ge , 81; 0.003 Y 11 0.002 Nb It 0.03 Mo /. 11 ■ 0.008 Ag 11 0.0008 In 11 0.10 Sn 11 0.009 La II 0.002 Ge 11 0.04 Sm I? 0.03 Gd 11 0.05 Yb II 0.004 224

PEK-r.28-.75 % Huebnerite, quartz . veins, at the Hawk claims , 1 km north of the Triangle T turnoff on Inter state 10, Texas Canyon, Little Dragoon Moun tains, Cochise County, Arizona. 32°03’19" N, 110°Q5'21" W. Stringers and pods of red-brown ■ huebnerite were found in N 40° E trending quartz veins that cut the Texas Canyon stock. Small amounts of scheelite.and sercite are also present in the quartz.

Mn . 20.8 % MnO 26.9 Fe . 0.47 FeO 0.60 W 56.3 . WCn 71.0

' 3 : ' : ' ' Mg ' 0.019 . MgO 0.032 A1 0.038 AI2O3 0.072 Si : 0.48 Si02 . :i.0: Ca ■ 0.46 . CaO 0.64 Ti 0.0090 Ti02 0.015 Cu 0.0039 CuO 0.0049 Zn 0.074 ZnO 0.092 Y tr< 0.002 Y 2O 3 t . . trc 0.002 Nb 0.36 Nb205 0.51 Ce V ■: 0.12 Ce2Q 3 ' 0.14 Yb 0.029 Yb203 0.033

Total 101.0 Na : nd: 0 . 06 K VI 0.10 Ca $1 0.0004 Sc w 0.001 V n 0.006 Mi 81 0.003 Ge II 0.003 Mo y 0 . 008 Ag -. . ■ " 0.0008 In 81 0.10 Sn 11 0.009 La II 0.002 Sm If 0 .03 Gd II 0.05 Ta II 0.20 225

PHK-33^75: Huebnente , quartz veins, at the Hawk claims, 1 km north, of the Triangle T turnoff on Inter state 10, Texas Canyon, Little Dragoon Moun- - tains, Cochise County, Arizona, 32°03,19" N, 110°05121" W, The huebnerite occurs with . scheelite in a quartz vein .that has muscovite selvages. . The quartz vein cuts the Texas Canyon Quartz Monzonite, and contains minor sphalerite and purple fluorite.

Mh 13.3 % MnO 17.8 Fe 0.94 FeO : 1.21 W ■ 61.2 WOg 77.2

Mg 0.028 MgO 0.046 Al • 0.034 AlxOq 0.064 Si ' ' ' : - 1.3 SiOy 2.8 Ca 0.36 CaO 0.50 Sc 0.0012 SC2O3 ' 0.0018 Ti 0.0094 TiOg 0.016 Cu 0.0011 CuO 0.0014 Y t K 01002 YgOg trc 0 . 003 Nby . . 0.095 NbaOs, 0.14 Ce 0.065 Ce203 0.076 Yb 0.018 Yb20 3 0.021

Total 100.0 Na nd< 0.06 K u 0.10 V li 0.006 Ni " 0.003 Zn It 0.03 Ge It 0.003 Mo II 0,008 Ag l i 0.0008 In li 0.10 Sn l i 0.009 La : ■ ■ H '0.002 Sm - 11 0,03 Gd II 0.05 Ta I t 0.20 226

PHK-36-75: Huebnerite, quartz vein 0.3 km north of the. Hawk claijris > Texas Canyon, Little Draqoon Mountains .Cochise County, Arizona. 3 2° 0.4 1 01" N , 110 05'40" W. The huebnerite occurs ' with scheelite and muscovite in a N 45° E trending, quartz '.vein within the Texas Canyon Quartz Monzonite stock.

' Mn 16.0 MnO ■ 20.6 Fe . 1.09 .' FeO 1.40 W 61.0 . WO„ ■■■ 76.9 3 Mg 0.025 MgO . 0.041 Al 0. 027 : AlgOg .. . 0.051 Si ■. 0.18 ' Si02 ' . . 0.39 Ca 0.33 . CaO . 0.46 Sc. . :C 0.0023 . Sc2Oo :. 0.0035 Ti . i 0,0057- : : : Ti02 0.0095 Cu 0.0033 CuO 0.0041 Zn . 0.088 ZnO 0.11 . Nb 0.087 N b 205 0.12 Mo 0.018. 1 MoOg. .... 0.027 Yb . 0.032 Yb203 . 0.036

Total. 100.2 Na nd< 0 . 06 K ■ , 11 ■ 0.10 v ... ■ ‘ ‘ v - 0 . 006 Ni. it 0.003 Ge It 0.003 Y » 0.002 Ag 11 0.0008 In It 0.10 Sn U 0.009 La « 0.002 Ce « 0.04 Sm . it 0.03 Gd 11 0.05. ■ Ta : ' « 0.20 227

PHK—3 7~75: Euehnerite, quartz vein. Bluebird .mine. Hill • 5456, -Texas. Canyon, Little Dragoon Mountains , Cochise, County, Arizona. 32°0 4 1 Qln N, 1.10° 05 '23v W. Ttie huebnerite occurs with scheelite and purple fluorite in a N 30 E trending quartz vein within the Texas. Canyon Quartz Monzonite stock.

Mn ' 19.4 % MnO 25.0 Fe . ' 1.22 : FeO 1.57 W 57.7 W03 . 72.8

Mg. ' 0.046 MgO 0.076 - A1 0.091 AI2O3 : 0.17 Si 0.41 . SiOg . 0.88 Ca 0.50 . CaO 0.70 Sc 0.0011 SC2O3 0.0017 Ti 0.0049 Ti02 0.0082 Cu 0.0051 CuO 0.0064 Zn 0.085, ZnO 0.11 Yb 0.027 Yb203 0.031

Total 101.4 ;■ % Na , nd< 0.06 K 11 0.10 V 11 0.006 Hi 11 0.003 Ge 11 0.003 Y . " 0.002 Nb: 11 0. 03 Mo 11 0.008 11 Ag 0.0008 In 11 0.10 Sn n 0.009 La 11 0.002 Ce n 0.04 Sm 11 0.03 Gd n 0.05 Ta .. n 0.20 228

PHK-43-75: Huebnerite,. Dividend Tunnel, 0.2 km northwest. of Walker Ranch, Texas Canyon Summit, Little Dragoon Mountains, Cochise County, Arizona. . 32°04 '• 1 7 1\T, 110°04 1 57" W. ' Some' of the . huebnerite occurs as Stringers in 10 cm wide quartz veins within-the Texas Canyon Quartz Monzonite. The remainder fills vugs within the quartz along with pinkish-orange scheelite. The quartz veins have selvages of greenish muscovite. Purple fluorite is disseminated with additional muscovite in the altered wall rock.

M n ' " 20.3 % MnO 26.2 % Fe , 0.66 . ' FeO ... 0.85

W ■ ■ . 55.0 W03 6:9.4

Mg 0.048 MgO . 0.080 Al 0.25 Al-^O-) . 0 .47 Si . . 0.44 ; . sid2 . .. 0.94 Ca 1.5 CaO .. 2.1 Ti 0.0083 . Ti02 0.014 Cu 0.093 CuO 0.12 Zn 0.13 ZnO 0.16 Mo ■ 0.038 M0O3 • 0.057 Ag 0.0056 Ag20 ... 0.0060 Yb 0.032 Yb2°3 0.036

Total 100 . 4 . . . % Na : nd< 0 .06 K ; . " 0.10 . Sc " 0.001 V " 0.006 Ni " 0.003 Ge " 0.003 Y " 0.002 Nb : " 0.03 In " 0.10 Sn . " 0.009 La " 0.002 Ce " 0.04 v Sm " 0.03 Gd :. " 0.05 Ta " 0.20 ' - ' : • 229 PIIK-45^-75: Wolframite, dump at the General Electric II mine, Las Guijas Mountains/ Arivaca Quadrangle, Pima County, Arizona, 31039,25.5" N, 111°22* 44.5" W. Pockets and stringers of black wolframite occur'in quartz veins that accompany a greenish-gray andesitic dike. .The dike and veins cut the Las Guijas Alaskite in an area where there are numerous, small pink aplite dikes.

Mn 6.90 % MnO 8.91 % Fe 7.14 , FeO . ■ 9.19 W 64.5 . ' W 0 o 81.3

Mg 0.050 MgO 0.083 A1 . 0.091 AI2O3 0.17 Si 0.15 Si02 0.32 Ca 0.0072 CaO . 0.010 Sc 0.019 SC2O 3 0.029 Ti 0.012 Ti02 0.020 :

Total 100.0 Na nd< 0.06 K " 0.10 V " 0,006 Ni " 0.003 ■ cu " : 0.0004 Zn " 0.03 Ge " 0.003 Y !' 0.002 Nb ■ ■ " ■: 0.03 Mo " 0.008 Ag " 0.0008 in " 0.10 Sn " 0.009 La " 0.002 Ce " 0.04 Sm " 0.03 Gd ■ " 0.05 ■ Yb ' " 0.004 Ta " 0.20 230

PHK-45x-75: Wolframite, workings between the Fernstrom mine and the entrance to the main haulage level of the General Electric II mine, Las Guijas Mountains, Arivaca Quadrangle, Pima County, Arizona. 31°39124" N, lir022,46" W. Black wolframite crystals up to 3.5 cm in - length were, found in 1 m wide boulders of quartz left by the miners. The wolframite crystals had microscopic coatings of sericite.

Sample.' #1 Sample #2 Sample #1 . Sample #2

Mn 8.37 % 11.1 % MnO . 10.8 % 14.3 % Fe . . 3.41 3.52 FeO 4.39 4.53 W 66.9 64.0 WOg 84.4 V 80.7

Mg 0.020 0.031 MgO 0.033 0.051 A1 0.013 0.084 AI2O3 0.025 0.16 Si 0.077 0.14 Si02 0.16 0.30 Ca 0.0038 ^ 0.042 CaO 0.0053 v 0.0059 Sc 0.012 0.017 SC2O3 0.018 ' 0.026 Ti 0.0036 0.0076 T1Q2 0.0060 0.013 Nb 0.061 ' . . nd< 0.03 - .. Nb^Og 0.087: — • Mo 0.029 tr< 0. 008 MoO^ 0.44 tr< 0.012

Tota1 100.4 % 100.1 %

K 88 . 0.10 V 81 . 0 . 006 Ni «1 0.003 cu 81 0.0004 Zn 88 0.03 Gs 18 0.003 Y 11 0,002 Ag 11 0.0008 In li 0.10 Sn lt 0.009 La "81 0.002 Ce ii . 0.04 Sm 88 . 0.03 Gd 11 0.05 Yb 11 .. 0.004 . Td 11 , 0.20 231

PHK-45y— 7.5: Wolframite, . workings between the Fernstrom mine and the entrance to the main .haulage level of the General Electric II mine,. Las. Guijas Mountains, Arivaca Quadrangle, Pima County, Arizona. 3i°39,24" N, 11102 2 ,46" W. Black wolframite crystals up to 3.5 cm in length were found in 1 m wide boulders of quartz left by the miners. The wolframite crystals had microscopic coatings of sericite.

Mn 10.8 % . MnO 13.9 % Fe 8.10 FeO 10.4 W . 59.5 75.0 ■ ^3... Mg 0.067 Mgo. 0.11 A1 0.064 . AI2Q 3 0.12 Si . 0.17 sio2 . . 0.36 Ca- 0.043 CaO 0.060 Sc 0.033 . Sc2°3 0.051 Ti 0.020 Ti°2 0.033

6 , — ------— - z Total 100.0 % Na : nd< Ol 06 K II 0.10 V » 0.006 Ni 1? 0.003 Cu ■ 11 0.0004 Zn II 0.03 Ge II 0.003 Y li 0.002 Nb II 0.03 Mo ' II 0.008 Ag 11 0.0008 In II 0.10 Sn 0.009 La II 0.002 Ce II 0.04 Sm ”■ 0.03 Gd .. . : ii 0.05 Yb ii 0.004 Ta H 0.20 232

PHK-31-76: Huebnerite r Adams mine, on the east side of . Cement Creek., 1.7 km northwest of Bonita Peak and 10 km north-northwest of Silverton, San Juan County, Colorado. 37°54101" N, 107°381 28" W. Red-brown crystals of huebnerite radiate out from quartz in a fan-like pattern. The quartz is vuggy and contains small rock frag ments. Some of the huebnerite forms thin plates and sheaf-life clusters up to 3.5 cm in length.

Mn 10.0 % ■ MnO 12.9 % Fe 0 . 86 FeO 1.1 W 45.6 W 0 3 ::.. 57.5 Mg ' 0.012 MgO 0.020 A1 0.18 Al203 0.34 Si 13.0 Si02 27.8 Ca - 0 i 014 CaO . 0.020 Ti 0.0036 TiC>2 0.0060 Y 0.0055 Y 203: 0.0070

’ Total 99.7 % K . nd< 0.10 Sc : " 0.001 V 1! 0.006 Cu || 0.0004 Zn 0 .03 Ge . . n 0.003 Nb it 0.03 Mo 11 O', 008 In ii 0.01 Sn ti 0.009 ■ La it 0.002 Ta ii 0.20 APPENDIX E

EMISSION SPECTROGRAPHIC ANALYSES OF ' SCHEELITE AND POWELLITE

The analyses were made by Hal W, Johnson, Pacific

Spedtrochemical Laboratory, Los Angeles, California.

233 234

PHK^31a-75: Scheelite, quartz veins at the Hawk claims, 1 km north of the Triangle T turnoff on Inter state 10, Texas Canyon, Little Dragoon Mountains, Cochise County, Arizona. 32°03119" N, 110°051 21" W . .Pinkish-orange scheelite and brown- black huebnerite occur together in N 40° E trending quartz veins that cut the Texas Canyon Quartz Monzonite stock. In several specimens the. scheelite formed haloes around the huebnerite stringers.

Ca 17.0 % CaO 2 3.8 Mo 0.10 M0O3 0.15 W 56.2 W0 3 70.9

Mg 0.020 MgO 0.033 Al . tr< 0. 008 A I 2O 3 tr< 0.015 Si. 0.029 Si02 0.062 Ti 0.0090 TiC>2 0.015 Mn 0.089 ' MnO , 0.11 Fe 0.041 , FeO * 0.053 Cu 0.00077' CuO 0.00096 Sr 0.35 SrO 0.41 Y 0.13 Y 2O 3 . 0.16 Ce tr< 0. 04 (-'e2°3 tr< 0.05 Yb 0.048 ' YboOs : 0.055 Pb 2.7 PbO ' . 3.1

Total ■ 98.9 % K nd< 0.10 Sc " 0.001 Nb " 0.03 Ba "0.08 La " 0.002 Sm " 0.03 Gd " 0.02 Ta " 0.20 Th " 0.10 235

PHK-41b-75: Powellite, mine dumps near the Mohawk shaftr ' Helvetia, northwestern edge of the Santa Rita Mountains, Pima County, Arizona. 31b51* 33" N, 110°46.T56" W. The powellite occurs in par tially marbled, grey-green limestone, and orange- brown garnet. Both matrices contain stringers and pods of secondary calcite. The rock is cut b y .3 mm wide quartz veinlets and has minor disseminated chalcopyrite. Molybdenite ' rosettes were found in some of the garnet.

Ca... 9<6: : % - CaO 13.4 Mo 3.8 M0O3 5.7 W 62.0 W03 78.2

Mg 0.12 MgO 0.20 A l . . 0 .075 . A I 2O 3 \ 0 .14 Si 0.88 Si02 1.9 Mn 0.054 MnO 0.070 Fe . 0.12 . -\ , FeO ; 0.15 Cu 0.00081 CuO 0.0010 Sr 0.041 .. SrO 0". 048

Total . 99.8

Sc tl 0.001 Ti 0.002 Co ?! 0.04 Y M 0.007 Nb; . ’ : 0.03 Ba «i 0.08 La ?! 0.002 Sm ?! 0.03 Gd I! 0.02 Yb ?l 0.004 Ta 8! 0.20 Pb n 0.10 Th . 81 0.10 236 PHK-43-75: Scheelite, Dividend Tunnel, 0.2 km northwest of Walker Ranch, Texas Canyon Summit, Little . Dragoon Mountains, Cochise County, Arizona. 32^04' 1711 N, 110°04 * 57" W. The pinkish-orange scheelite occurs with huebnerite and colorless fluorite in vuggy quartz veins. The 10 cm wide quartz veins trend N 40° E and cut the Texas Canyon Quartz Monzonite stock.

Ca 17.6 % CaO 24.6 Mo 0.02 M0O3 0.03 W 58.8 WOj 74.2

Mg 0.016 . MgO . 0.027 A1 0.075 . AI2O3 0.14 Si 0.19 Si02 0.41 Ti 0.0030 Ti02 0.0050 Mn 0.036 MnO 0.046 Cu 0.00041 CuO 0.00051 Sr 0.27 SrO . 0.32 Y 0.024 Y2°3 0.030 Yb 0.028 * Yb203 0.032

.Total 99.8 o\o

K nd< 0.10 Sc " 0.001 Fe " 0.006 Nb " 0.03 Ba " 0.08 La " 0.002 Ce " 0.04 Sm " 0.03 Gd " 0.02 Ta " 0.20 Pb " 0.10 Th " 0.10 237

PHK-48--75: Scheelite, large quartz vein cutting the Cam brian Bolsa Quartzite, Reef mine, Carr Canyon, . east side of the Huachuca Mountains , Cochise County, Arizona. 31025,37.5" N, 110 17,16.8" W. Pale yellow-green scheelite occurs in massive quartz along with stringers of galena and oxi dized pyrite cubes.

■ Sample #1 Sample #2 Sample #1 Sample #2

Ca 19.4 % 8.4 % CaO 27.1 % 11.8 % Mo 0.17 0.16 M0O3 0.26 7 0.24 W 57.0 69.0 WO3 71.9 87.0

Mg 0.0072 0.0052 MgO 0.012 0.0086 Al 0.033 0.052 Al203 0.062 0.098 Si 0.017 0.031 Si02 0.036 0.066 Ti 0.0069 . 0.0053 Ti02 0.012 : . 0.0088 Mn 0.014 0.0047 MnO 0.018 0.0061 Cu nd< 0.0003 0.0027 CuO — . 0.0034 Sr 0.095 0.063 SrO . 0.11 0.075 Y 0.062 . 0.061 . Y203 ' 0.078 . 0.077 Ce tr< 0.04 0.075 Ce203 tr<0.05 0.088 Yb 0.021 0.012 Yb203 0.02.4 0.014 Pb tr< 0.10 . 0.57 PbO tr< 0.11 0.61

Total 99.8 % 100.1 %

K ndc 0 .10 Sc " 0.001 Fe " 0.006 .Nb ". 0.03 Ba " 0.08 La " 0.002 Sm " 0.03 Gd " 0.02 Ta " 0.20 Bi " 0.002 Th " 0.10 . 238

PHK-37--76: Molybdian scheelite, hydro thermal ly altered . pegmatitic phase of a gneiss., 1 . 6 km north of BM 32 85, near San Juan Spring, southeastern side of the Quinlan Mountains., Pima County, Arizona. ' 31^56'12" N, 110°40'53" W. Molyb dian .scheelite is disseminated in a pegmatitic matrix of quartz, feldspar, and tan garnet. Some of the samples also contain yellow-green crystals of epidote.

■ Ca .. 6.9 % . CaO 9.7 Mo 0.28 M0O3 0.42 W 71.3 W°3 89.9

Mg 0.011 MgO ; 0.018 . Al 0.14 . AlgOg 0.26 Si 0.13 Si02 0.28 ; Mn 0.019 MnO 0.025 Fe 0.036 FeO v 0.046 Cu 0.00034 CuO 0.00043 Sr tr< 0.003 SrO . tr< 0.004

Total 100.7 K nd< 0.10 Sc " 0.001 Ti " 0.002 . Co " 0.04 Y " 0.007 Mb " 0.03 Ba " 0.08 La " 0.002 Sm " 0.03 Gd " 0.02 Yb. " 0.004 Ta " 0.20 Pb " 0.10 Th . " 0.10 J 239

PHK-43-76: Scheelite, OK Bang mine, OK.Bang, Seo Myeon, southwest of Ulchin, KyeOng Buk, east coast of South Korea. 36°54,-40" N z 129o08,45" E. The brownish-white to light brownish—yellow sche elite is intergrown with fine flakes of black biotite. Both minerals are in a matrix of quartz.and dull white.feldspar.

Ca 17.0 % CaO 23.8 % Mo 0.071 MoO- 0.11 W 60.2 wo33 75.9

Mg 0.018 MgO 0.030 Al. ■ 0.15 . AloOo 0.28 Si 0.046 S102 0.098 Mn 0.037 ' - MnO 0.048 Fe 0.057 FeO 0.073 . Cu 0.00029 CuO 0.00036 Sr 0.036 SrO 0.043

. Total 10 0.'4 % K ncK 0.10 Sc : " 0.001 Ti " 0.002 Co " 0.04 Y " 0.007 Nb " 0.03 Ba " 0.08 La : " 0.002 Sm " 0.03 Gd • " 0.02 Yb " 0.004 Ta " 0.20 Pb . " 0.10 Th " 0.10 240

PHK-13a-77: Molybdian scheelite, 234-F stockpile, West pit of the ANAMAX Twin Buttes mine, eastern pedi ment of the Sierrita Mountains, Sahuarita, Pima County, Arizona. 31053,31" N, 111°02'22" W. ■Scheelite pods, 1.2 to 1.5 cm in diameter, occur in' a guartz-epidote-sulfide veinlet that cuts silicified, diopside-rich rock. The scheelite contains 1 mm diameter inclusions of chalcopyrite. The quartz-epidote-sulfide veinlet has a 1 cm wide halo of tremolite and actinolite.

Ca 11.0 % : CaO 15.4 Mo 0.41 MOO, 0.62 W 66.0 W0 3 83.2

Mg 0.030 MgO 0.050 Al 0.097 AI2O3 0.18 Si 0.31 Si02 0.66 Ti 0.014 Ti02 0.023 Mn 0.024 MnO 0.031 Fe 0.36 FeO • 0.46 Cu 0.039 CuO 0.049 Sr 0.026 SrO 0.031 Y 0.050 Y2O3 0.063 Ce 0.045 06263 0.053 Yb 0.011 Yb203 0.013

Total 100. 8 % K nd< 0.10 Sc . n 0.001 Nb 11 0.03 Ba « 0.08 La 11 0.002 Sm 01 0.03 Gd If 0.02 Ta « 0.20 Pb 81 0.10 Bi 11 0.002 Th 11 0.10 241 PHK-16-77: Molybdian scheelite, quartz vein cutting al- (AMAX 1013) tered Paleozoic limestones at the Senator Morgan mi n e , 3.2 .km west-southwest of the ANAMAX Twin Buttes pits, eastern pediment of the Sierrita Mountains, Sahuarita, Pima County, Arizona. 31 53*14" N, 111°04,3.2" W. The 2 m wide quartz vein contains finely disseminated scheelite with an average grain size of 2 mm. The scheelite varies in color from pure white to pinkish yellow, and fluoresces bright white to pale yellowish-white. The quartz vein inter sects. a skarn zone of magnetite, actinolite, and garnet near the main shaft of the Senator Morgan mine. The magnetite-actinolite-rich rock also contains minor chalcopyrite and hema- . tite.

Split #1 Split #2 Split #1 . Split #2

Ca 11 . % 15. % CaO 15.4 % 21.0 % Mo 0.29 2.1 . MoCU • 0.43 3.2 W 62. 58. . WO33 • 78.2 73.1

Mg 0.0077 0.0072 MgO . 0.013 0.012 Al 0.11 0.078 AI2O 3 0.21 0.15 Si 2.4 0.18 Si02 5.1 0.39 Ti 0.0051 :: ndc 0.002 TiOg 0.0085 nd< 0.003 Mn 0.0052 0.0045 . MnO : , 0.0067 0.0058 Fe 0.026 0.037 FeO 0.033 0.048 Cu 0.0028 0.0011 CuO 0.0035 0.0014 Sr 0.052 0.064 . SrO V 0.061 0.076 Pb 0.23 . 0.79 PbO 0. 25 0.85 Bi 0.039 0. 070 b 12°3 0.043 0.078

Total 99.8 % 98.9 % K nd< 0.10 Sc " 0.001 Y " 0.002 Nb " 0.03 Ba " 0.08 La " 0.002 . Ce " 0.04 Sm " 0.03 Gd " 0.02 Yb " 0.004 Ta " 0.20 Th " 0.10 APPENDIX F

EMISSION SPECTROGRAPHIC ANALYSES OF RUTILE, MAGNETITE, AND HEMATITE

The analyses were made by Hal W. Johnson, Pacific

Spectrochemical Laboratory, Los Angeles, California.

242 243 PHK-12—72: . Tungsten-rich rutile, New Year's Eye breccia pipe, 3760 ft bench, Esperanza pit, Sierrita Mountains, Sahuarita, Pima County, Arizona. 31°51'59" N, il0°07'32" W. Black crystals of rutile, up to 1 cm in length, occur with molyb denite in a matrix of sericite, orthoclase, and quartz. Qualitative x-ray fluorescence analysis by the Duval Sierrita Corporation1s laboratory confirmed the presence of Ti, Fe, Nb, Sn, and W„

Split #1 Split #2 Split #1 Split #2

Ti 57.8 % 0.021 % 96.41 % 0.035 % Ti02 • Mg : . 0.017 •: 0.021 . MgO.. 0.028 0.035 Al . . 0.097 0.078 A I 2O 3 . 0.183 0.147 Si 0.67 0.56 Si02 *.: 1.43 1.20 Ca 0.034 0.0085 . CaO 0.048 0.012 Sc 0.0041 0.0044 SC2O 3 0.0063 0.0068 V 0.18 0.15 V 2O 5 0.32 0.27 Cr 0.13 0.090 Cr2°3 0.19 0.13 Fe 0.52 0.71 FegOj 0.74 1.02 Cu 0.038 0.023 . CuO 0.048 0.029 Nb 0.10 0.16 Nb205 0.14 0.23 Sn tr< 0.03 ncK 0.03 SnOo tr< 0. 04 . — W 0.81 0. 90 W0 3 . 1.02 1.14 •

Total 100.91 % 100.62 % Na nd< 0.40 K " 0.50 Mn " 0.01 Mo " 0.05 Sb " 0.08 Ta " 2.0 244

PHK-1--75: Rutile, Vitoria da Conguista, Serra do Periperi, State of Bahia, Brazil„ 140511 s , 40°511 W- (The exact latitude and longitude were unavail able.) The sample was. taken from a penetration twin of red-black rutile that measured 5 x 3 x 3 cm. ■ An orange-brown earthy material was found in niches in the crystal.

Ti ’ 59.3 ' % Ti02 9 8.9 %

Mg; 0.0064 MgO' 0.011 A1 0.11 A I 2O 3 0.21 Si 0.32 Si02 0.68 Ca 0.015 CaO 0.021 Sc tr< 0.001 SC2O3 tr< 0.002 . V 0.065 V 2O 5 0.11 Cr 0.027 Cr2P 3 . : 0.039 , Fe 0.31 Fe2°3 0.44 Mb 0.096 Nb2°5 . 0.14 ' ,

Total •' " 100.6 %

Na ndc 0.40 K 11 0.50 Mn 11 0.01 Cu . 11 0.0008 Mo 11 0.05 Sn 11 0 .03 Sb H 0.08 Ta 11 2.0 w ii 0.50 2.45

PHK-02-77r Tungsten-rich rutile, Santo. Nino mine, Mt. (UAMM-M185) ■ Washington, Patagonia Mountains, Santa Cruz County, Arizona. 31021* 41" N, 110°43'03" W. Chips were obtained from a 9x15x20 cm block on display in the Univeristy of Arizona Mineralogical Museum. The block contains feather-shaped stringers (4 x 1 x 0.5 cm) of purple to red-black rutile. The rutile occurs in a whitish-yellow to yellowish-brown matrix of feldspar together with pods of pyrite and other sulfides.

Split #1 ' Split #2 Split #1 Split #2

Ti 51.. . % 51. TiQ 2 85.1 % 85.1 %

Mg 0.017 0.014 MgO - 0,028 0.023 Al.. ' 0.14 0.15 AlgOg 0.26 0.28 Si 1.9 . . . 1.7 Si02 . 4.1 3.6 Ca ; 0.084 0.060 CaO 0.12 0.084 V 0.17 . 0.19 v 2°5 0.30 0.34 Cr 0.17 0.13 Cr203 , 0.25 . . 0.19 Mn 0.070 nd< 0.02 MnO 0.090 Fe ' - 3 .8 3.8 Fe2°3 5.4 • 5.4 . Cu 0.036 0.083 CuO 0.045 0.104 Y.. ' 0.12 tr< 0.02 Y2O 3 ..: 0.15 tr<0.03 Zr 0.36 0.42 2r02 0.49 0.57 Sn tr< 0.06 0.42 Sn02 tr< 0.08 0.53 Sb . 0.43 nd< 0.08 Sb205 0.57 nd< 0.11 W ■■ 1.7 - 3.2 WO 3 2.1 ' 4.0 PB 0.46 nd< 0.10 PbO 0.50 nd 0.11

Total 99.6 % 100.3 % 236 3?HKr-03^77: Rutile, Mina el Tisur, Pluma Hidalgo, Sierra (UAMM-260.9) de Oaxaca, State of OaxacaRepublic of Mexico. 15°541 N, 96°23' W. (The exact latitude and longitude were unavailable.) Chips of red-brown to .red-violet rutile were taken from a 10 x 10 x 6 cm specimen in the University of Arizona Mineralogica1. Museum. The specimen contained numerous small intergrowths of a yellow-green fo pistachio-green silicate.

Split #1. Split : #2 Split #1 Split #2

Ti 57. % 57. %: Ti02 95.1 % .95.1 %

Mg Q .11 0.20 MgO 0.18 0.33 Al 0.13 . 0.17 AI2O 3 0.25 . 0.32 Si . . 1.1 1.3 Si02 2.4 2.8 Ca 0.23 , 0.42 CaO : . 0.32 0.59 : V . 0.12 0.18 • v 2°5 0.21 . 0.32 ■ Cr 0.024 ;; 0.024 CrgOs 0.035 0.035 Fe 6.33 0.53 Fe 2°3 0.47 0.7.6. 0.47 0.61 . 0.63 0.82 Zr • Zr02

Total 99.6 % , .101.1 %

Mn nd<0 .02 Cu II 0.002 Y 11 0.02 Sn II 0 . 06 Sb II 0.08 w » 0.40 Pb 81 0.10 247

O l : Rutile, Champion Sillimanite mine, Jeffrey mine . Canyon, 6.1 km west-southwest of White Mountain Peak, White Mountains, Mono County, California. 37o37,09" N, 118°19'13" W. Red-black crystals of rutile ranging in size from 0.2 to 1.0 cm occur in a matrix of pinkish-brown andalusite and brownish-white pyrophyl- lite. The White Mountain deposit was mined from 1922 to 1945 for andalusite. The andalusite, which.was used in the manufacture of high-grade porcelain for spark plugs, forms irregular segregations in a large mass: of quartzite, and is associated with corundum, . diaspore, muscovite/ alunite, and lazulite. The : quartzite is part of a complex of Precambrian schists that has been intruded by Mesozoic granites (Kerr, 19 32) .

„ .. t ...... , / Ti 58.3 % Ti0 2 97.2 , %

Mg : 0.0021 . MgO . 0.0035 Al- . 0.087 . A I 2O 3 0.16 Si 0.74 Si02 1.6 Ca 0.0047 CaO . 0.0066 , V 0.11 V 2O 5 . ... . 0.20 Cr 0.031 0x203; 0.045 Fe 0.34 Fe-2 0'3 . 0 = 49 Mb 0.074 . • Nb^Og . 0.11 Sn tr< 0.03 Sn02 tr< 0.04 Sb 0.48 Sb205 0.64

Total 100.5 % •Na . . nd< 0.40 K " 0.50 Sc " 0.001 Mn " 0.01 Cu " 0.0008 Mo " 0.05 Ta " 2.0 W " 0.50 248

PHK-5Q-75.: Magnetite,' large magnetite pod in altered Paleozoic limestones. New York mine. Cuprite district, northern end of the Santa Rita Moun- . tains, Pima County, Arizona. ' 31°55'55" N, 110°43120" W. The magnetite forms poorly de fined bands, 1 to 3 cm wide, in whitish-grey green to brown garnetite. Some of the magnetite contains blebs and veinlets of chalcopyrite and pyrite.

Split #1 Split #2 Split #1 Split #

Fe 70. % 70. - . % FezOs(2/3)66.7 % 66.7 o\o FeO (1/3)30.0 30.0

Mg 0.074 0.086 / MgO 0.12 0.14 Al 0.092 0.10 A I 2O 3 , 0.17 0.19 : Si ■ 0.75 0.86 Si02 1.6 1.8 Ca : 1.1 1.2 CaO 1.5 . 1.7 Ti 0.010 0.0086 ■ Ti0 2. 0.017 , 0.014 V, : 0.0019 nek 0.001 - ; v 2o 5 0.0034 Mn 0.13 0.10 Mno. 0.17 0.13 Cu 0.0052 0.0044 CuO 0.0065 0.0055 Zn . 0.026 tr<0 .02 ZnO 0.032 tr< 0. 02 . Mo 0.0084 nd< 0.008 Mo03 0.013 --

Total 100.3 % . 100.7 Cr nd< 0.0004 Co " 0.0009 Sr " 0.003 249

PHK-1-77.: Magnetite, magnetite-actinolite—chalcopyrite skarn zone in altered Paleozoic limestones. Senator Morgan mine, 3.2 km VfSW of the ANAMAX Twin Buttes pits, eastern pediment of the Sier- rita Mountains, Sahuarita, Pima County, Arizona. 31°53'14" N, 111°04,32" W. Massive, purple- black magnetite is intergrown with chalcopyrite and 15 x 5 x 5 mm clusters of grey-green actinolite. -Some specimens also contain minor hema tite.

Split #1 Split #2 Split #1 Split #2

Fe 65. % 58. % Fe2°3 (2/3) 62.0 :% 55.3 FeO ,(1/3) 27.9 24.9

Mg 0.16 0.10 MgO. 0.27 0.17 Al 0.033 0.043 ■AI2O3 0.062 0.081 Si 4.2 8.7 Si02 9.0 18.6 Ca 0.032 0.017 CaO 0.045 0.024 Ti 0.0092 . 0.0064 Ti02 0.015- 0.011 V . 0.0024 0.0043 V 2O5 0.0043 0.0077 cr 0.00098 nd< 0 . 00 0 4 : Cr203 0.0014 Mn 0.092 0.078 MnO . 0.119 0.101 Co nd< 0.0009 0.0058 Co203 — 0.0082 Cu 0.0067 0.0055 CuO 0.0084 0.0069 Zn tr< 0.02 tr< 0.02 ZnO ;; tr< 0.02 : tr< 0.02 Mo nd< 0.008 0.030 mqo3 0.045

Total 99.4 % 99.3

Sr nd< 0. 003 250

PHK-27^76: Hematite,, massive specularite from a prospect along the road between Amado and the Smithsonian Astrophysical Observatory on Mount Hopkins, Sheeby Canyon, Santa Rita Mountains.., Santa Cruz County, Arizona. 31 40'37".N, 110o55'28" W. The sample was•collected• from a highly altered, silicified breccia near the contact between the Laramide Josephine Canyon diorite and the upper Cretaceous Salero Formation. The breccia fragments are cemented, together by massive specularite. Metallic black, flakes of specu larite are disseminated throughout the breccia and form rosettes up to 1 cm in diameter.

Fe ' 59. % 84.4 % Fe2°3 Mg . 0.13 MgO 0 .27 A1 0.16 AI2O 3 0.30 Si 1.3 Si02 2.8 c a ... 8.3 CaO .: ' 11.6 Ti : 0.0085 Ti02 0.014 V 0.0034 v 2°5 0.0061 Mn 0 . 89 MnO 1.1 Sr tr< 0.003 SrO tr< 0.004 Mo • 0.022 ... Mo03 . 0.033

Total 100.5 % .

Cr nd< 0. 0004 Co . " 0.0009 Cu " 0.005 Zn " 0.02 APPENDIX G

. CONVENTIONAL X-RAY FLUORESCENCE ANALYSES OF FERBERITE, WOLFRAMITE., AND HUEBNERITE

251 252

Huebnerite and wolframite, quartz veins in the Texas Canyon Quartz Monzonite stock. Little Dragoon Mountains, Cochise County, Arizona. PHK-6-71, Little Fanny claims, Sheep.Basin? PHK-29a-75, quartz vein 0.3 km • north of the Hawk claims? PHK-33-75, Hawk claims? PHK-33z-75, Hawk claims? PHK-43-75, Dividend Tunnel, Walker Ranch. .

Weight Percent

. Pellet #1 Pellet #2

PHK-6-71 WO 3 76.48 ± o.oi Huebnerite FeO 0 . 89 0.01 MnO 22.90 0.20 100.27 ± 0.22

PHK-29a-75 WO 3 76.39 ± 0 . 02 Huebnerite • FeO ■ 1.36 0.01 MnO 21.13 0.04 98.88 ± 0.07

PHK-33-75 WO 3 76.26 ±0.03 76.26 ± 0.01 FeO ' 1.31 0.02 1.33 0.01 MnO 18.10 0.19 18.42 0.32 95.67 ± 0.24 96.01 ±0. 34

PHK-33Z-75 WOo 76.42 ± 0.01 76.42 ± 0.01 Huebnerite FeO 1.52 0.01 1.53 0.01 MnO 20. 80 0.21 20.74 0.10 98.74 ± 0.23 9 8.69 ± 0.12

PHK-43-75 WO 3 76.15 ± 0.01 76.05 ± 0.01 Wolframite FeO 6.81 0^ 01*: 6.86 0 .01* MnO 19.99 0.13 18.70 0.09 102.95 :fc 0.15 101.61 ± 0.11

*Suspected interference. 253

Huebnerite and wolframite, quartz veins in the Las Guijas Alaskite stock. Las Guijas Mountains, Pima County, Arizona. PHK-24-71, General Electric II mine; PHK-45a-75, mine dump at the General Electric II mine; PHK-45y-75, workings between the Fernstrom mine and the General Electric II mine.

Weight Percent

• Pellet #1 Pellet #2 ■

PHK-24-71 WO3 76.42 ± 0.01 76.43 ±0.02 Huebnerite . FeO 2.82 0.02 2.87 0.02 MnO 20.31 0.32 20.57 .. 0.10 99.55 ± 0.35 99.87±0.14

PHK-45a-75 . . WO 3 76.44 ± 0.01 76.42 ± 0.01 Huebnerite FeO - 1.0 8 o.oi : 1.07 0 . 01 ' MnO 21.96 0.19 21.59 0.36 99.48 + 0.21 99 .08 ± 0.38

PHK-45y-75: . WO 3 76. 46 ± 0.01 76.45 f 0.01 Wolframite . . FeO: 4.83 0.03 4.79 0.01 MnO 18.15 0.06 17.93 0 .02 99.44 ±.0.10, 99.17 ± 0.04 254

Ferberite, Ventura breccia pipe , Cox Gulch, west central part of the Patagonia Mountains, Santa Cruz.County, Arizona.

Weight Percent

PHK-30-69 WO3 76.40 ± 0.02 Ferberite FeO 17.25 0.03. MnO 2.43 0.03 96.08 ± 0.0 8 255

Ferberite, quartz veins at the Panasqueira mines, north western side of the Rip Zezere, Beira Baixa, central Portugal.

Weight Percent

Pellet #1 Pellet #2-

PHK-4-75 WOo 76.36 ± 0.01 76.37 ± 0.01 Ferberite . FeO 17.79 0.01 • 18.04 0.05 MnO 2.81 0 .04 2 .87 0.01 96.96 ± 0.06 97.28 ± 0 .07

PHK-5-75 WO 3 76,,36 ± 0.01 76,,34 ± 0 . 01 Ferberite ' FeO 17...93 - 0.05 17.,82 0.05 MnO 2.66 0.03 2.62 0.03 96.95 ± 0.09 96.78 ± 0.09 APPENDIX H

THERMODYNAMIC PROPERTIES OF SELECTED MOLYBDENUM AND TUNGSTEN COMPOUNDS, INCLUDING THE DATA FOR THE MOLYBDATE AND TUNGSTATE ANIONS

References: -used in the first column are identified as:

HI - Degroise and Oudar, 1970

H2 - Dellien, McCurdy, and Helper, 1976 -

H3 - Fredrickson and Chasanov, 1971

H4 *:Kelley, 1960

• H5 - Landee and Westrum, 1976

. H6 Lyon and We strum, 1974

H7 - McBride and Westrum, 1976

H8 - O 'Hare, 1974

H9 - O'Hare, Benn, Cheng, and Kuzmycz, 1970 \

HI0 - 0 5Hare and Hoekstra> 1974.

Hll - Rezukhina and Kashina, 1976

HI2 - Robie and Waldbaum, 1968

Hi3 - Wagman et al., 1969

256 AHf Gibbs Free o Enthalpy of Energy of Cp Formation at Formation S Heat Capacity 290.15 K at 298.15 K Entropy Parameters* Name and Formula (25°C) (25°C) (cal/deg- (cal/deg-mol) (Reference) (kcal/mol) (kca1/mol) mol) a ; b c

Molybdenite - 6 5 . 8 ± . - 6 3 . 7 ± 1 4 . 9 6 ± 1 7 . 1 3 5 7 1 . 7 8 0 3 - 2 . 2 0 1 4 M 0S 2 c r y s t a l 1.2 1.2 0.02 (H 3,4,7,9, 1 2 , 1 3 )

Tungsten!te - 7 1 . 3 ± - 7 1 . 2 ± 2 2 . 7 ± 1 6 . 8 8 * * 1 . 7 8 * * - 2 . 20** WS 2 c r y s t a l 0.2 0.6 2.0 (11 1,12,13)

Mplybdic acid - 2 5 0 . 0 - 2 1 6 . 4 36.** 38.07** 5.90** - 3 . 6 8 * * H 2M 0O 4 c r y s t a l (H 1 3 )

Tungstic acid - 2 7 0 . 5 ± -240.0 34.6 i 2 5 . 1 7 * * 5 . 8 7 * * 112WO 4 c r y s t a l 0 . 4 6 . (11 13)

P o w e l l i t e - 3 6 9 . 5 ± - 3 4 4 . 0 ± 2 9 . 3 ± 31.74** 6.98** - 5 . 2 4 * * C a M o 04 c r y s t a l 0 . 3 0 . 3 0.2 (II 12 )

S c h e e l i t e - 4 0 2 . 4 ± - 3 7 6 . 9 ± 3 0 . 2 ± 29,42** 6.95** - 1 . 5 6 * * C a W 04 c r y s t a l 0 . 5 0 . 5 0.2 (H 4) 257 0 A G f ° ; AHf. G i b b s F r e e Enthalpy of E n e r g y o f cp° Formation at F o r m a t i o n S ° . Heat Capacity 29 8, 1 5 K a t 29 8. 1 5 K E n t r o p y Parameters* Name and Pormu 1a ' (2 5° C ) . ( 2 5 & C ) : ( c a l / d e g - .( c a 1/ d e g - m o l ) (Reference) ( k c a l / m o l ) (kcal/mol) mol) a b c

Manganous molyb- -284.7 32.9** 31.2** 7.84** -4.56** d a t e M n M o O c r y s t a l (H 13) iluebnerite - 3 1 1 . 9 3 1 . 6 6 28.86 7.81** -0.88** M n W 04 c r y s t a l . (H 5 , 1 3 )

Ferrous molyb- - 2 57. - 2 3 3 . 30.9 31.7** 7.90** , -4.35** d a t e P e M o 04 c r y s t a l (li 13)

F e r b e r i t e - 2 7 6 . 8 ± -252. 31.61 ± 29.41 7.87 -0.67 F 0WO 4 c r y s t a l . 2.0 0 . 0 5 (11 6,11,13)

W u l f e n i t e - 2 5 1 . 6 - 2 2 7 . 4 3 9 . 6 9 ± 30.67** 9.90** -3.68** P b M o 04 c r y s t a l 0 . 5 . (11 2,12,13)

S t o l z i t e - 2 6 9 . 4 4 0 . 2 0 ± 2 5. 8 2 9 . 4 2 P b W 04 c r y s t a l 0 . 5 (H 2 , 1 3 ) 258 Hf G i b b s F r e e Estimated Ionic Partial^ Enthalpy of Energy of Q Molal Heat Capacities, C Formation at Formation S between T and 25%* ^ 298.15 K at 298.15 K Entropy Name and Formula (25%) (25%) (cal/deg- (Reference) (kcal/mol) (kcal/mol) mol) 60° 100° 150° 200° 250° 300°

Holybdate anion - 2 3 8 . 3 ± - 1 9 9 . 8 2 + 7 . 0 ± -r-108 - 9 4 - 1 0 0 - 9 4 -102 -114 -120 M 0O 4":, aqueous 0.2 0 . 7 0 2 . 4 (s tandard s ta t e , m = l ) (H 8,10,13) .

Tungstate anion -256.5 (-222.5 ±) 6 . 1 1 6 -110 -96 -102 -96 -104 -116 -122 WO 4"',- a q u e o u s 1.0 (standard state, m = l ) (H 2 , 1 3 )

v5 -2, *Heat capacity, C °(T) = a t (b x 10"^T) + (c x 10° T z) where T is the temperature in P k e l v i n s

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