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Geology of the Granite Peak stock area, Whetstone Mountains, Cochise County, Arizona Item Type text; Thesis-Reproduction (electronic); maps Authors DeRuyter, Vernon Donald Publisher The University of Arizona. Rights Copyright © is held by the author. Digital access to this material is made possible by the University Libraries, University of Arizona. Further transmission, reproduction or presentation (such as public display or performance) of protected items is prohibited except with permission of the author. Download date 07/10/2021 05:09:43 Link to Item http://hdl.handle.net/10150/555132 GEOLOGY OF THE GRANITE PEAK STOCK AREA, WHETSTONE MOUNTAINS, COCHISE COUNTY, ARIZONA by Vernon Donald DeRuyter A Thesis Submitted to the Faculty of the DEPARTMENT OF GEOSCIENCES In Partial Fulfillment of the Requirements For the Degree of MASTER OF SCIENCE In the Graduate College THE UNIVERSITY OF ARIZONA 1 9 7 9 STATEMENT BY AUTHOR This thesis has been submitted in partial fulfillment of require­ ments 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 thesis are allowable without special permission, provided that accurate acknowledgment of source is made. Re­ quests for permission for extended quotation from or reproduction of this manuscript in whole or in part may be granted by the head of the major de­ partment or the Dean of the Graduate College when in his judgment the pro­ posed use of the material is in the interests of scholarship. In all other instances, however, permission must be obtained from the author. APPROVAL BY PROJECT SUPERVISOR This thesis has been approved on the date shown below: ^ /?/> / SPENCER R. T I T L E Y ^ ~ • DATE Professor of Geosciences . ACKNOWLEDGMENTS The author wishes to express appreciation to Dr. Spencer R. Titley for his encouragement and careful guidance as thesis director. Thanks are also due Dr. John Mw Guilbert and Dr. John W. Anthony for their advice as thesis committee members, Dr. Terah L. Smiley for his encouragement as Graduate Student Coordinator, and Dr. Bert E. Nordlie for his help during early work on the study. The subsurface relationships and interpretations in this study could not "have been developed without valuable drill hole logs, assays, and samples provided by Mr. Abe Kalaf and personnel of the Duval Corpor­ ation. A very special thanks is due my wife, Dorothy, and children, Eric and Sara, for their patience and understending during the months of my absence in pursuit of completion of this study. iii TABLE OF CONTENTS Page LIST OF ILLUSTRATIONS ..................................... .. vii LIST OF T A B L E S ................................................... ix ABSTRACT.................................... ...................... x CHAPTER 1. INTRODUCTION................................................ 1 Purpose and Scope of Study............................. 1 Method of Treatment................................... 2 Location................................... 2 Accessibility .......................................... 3 Previous W o r k .......................................... 3 2. REGIONAL GEOLOGICAL SETTING ............................... 7 Regional Stratigraphy . Regional Structural Setting 00 3. GEOLOGY OF THE WHETSTONE MOUNTAINS......................... 12 Physiography................ 12 Stratigraphy. .......................................... 14 Igneous R o c k s .......... 14 Structure .............................................. 15 Precambrian Orogeny ............................... 17 Paleozoic Epeirogeny............................... 17 Nevadan Block Faulting............................. 17 Laramide Orogeny................................... 18 Late Cenozoic Block Faulting....................... 18 4. STRATIGRAPHY OF THE GRANITE PEAK A R E A ..................... 19 Paleozoic Stratigraphy................................. 19 , Pre-Earp Formations ............................... 19 Earp Formation.................... 20 Colina Limestone. .................................. 20 Epitaph Formation................................. 21 Scherrer Formation............................. 23 Concha Limestone................................... 23 Rainvalley Formation.................... 24 iv V TABLE OF CONTENTS— Continued Page Post-Paleozoic— Pre-Cretaceous Unconformity .......... 24 Lower Cretaceous Stratigraphy ........ .............. 25 Willow Canyon Formation ................. ..... 25 Apache Canyon Formation........................... 27 Shellenberger Canyon Formation. ................... 27 Turney Ranch Formation ........... 28 Correlation of Lower Cretaceous Stratigraphy. 29 The Piman Phase of the Laramide Orogeny and Upper Cretaceous Stratigraphy ..................... 29 Cenozoic Gravels. .................................... 31 5. IGNEOUS ROCKS IN THE GRANITE PEAK A R E A . ................... 33 Rhyodacite Sills................................. 34 Occurrence, Form, and Geologic Relations.......... 34 Petrography.......... 34 Relative Age. ...................................... 36 Granodiorite Porphyry ................................. 36 Occurrence, Form, and Geologic Relations.......... 36 Petrography........................................ 38 Relative Age........................................ 40 Quartz Gabbro .......................................... 41 Occurrence, Form, and Geologic Relations.......... 41 Petrography........................................ 46 Relative Age................................... - . 48 Granodiorite......................... 49 Occurrence, Form, and Geologic Relations......... 49 Petrography.................... 51 Relative and Radiometric Age....................... 54 Host rock Alteration and Mineralization.......... 55 Xenoliths in Granodiorite ......................... 58 Aplite Dikes............................................ 63 Distinguishing Characteristics..................... 63 Petrography........................................ 64 Relative Age........................................ 64 Quartz Monzonite Porphyry ............................. 65 Occurrence, Form, and Geologic Relations. ..... 65 Petrography........................................ 69 Relative A g e ..................................... 71 Alteration and Mineralization ..................... 71 Quartz Latite Porphyry Dike ........................... 74 Occurrence, Form, and Geologic Relations.......... 74 Petrography ........................................ 74 Relative Age............ 77 vi TABLE OF CONTENTS--Continued Page Breccia Zones......................................... 77 Definition.................. 77 Occurrence and Form.................. 81 Relative A g e ..................................... 82 Granite........................ 82 Occurrence, Form, and Geologic Relations ......... 82 Petrography. ...................................... 84 Relative Age ...................................... 85 Basalt Porphyry. ...................................... 85 Occurrence, Form, and Geologic Relations......... 85 Petrography.................. 87 Relative Age ...................................... 92 Rhyolite Vitrophyre................................... 94 Occurrence, Form, and Geologic Relations ......... 94 Petrography........................................ 94 Relative A g e ............................... 96 Petrology of Igneous Rocks ........................... 97 6. STRUCTURAL DEVELOPMENT IN THE GRANITE PEAK AREA.......... 100 7. ECONOMIC POTENTIAL OF MINERALIZATION ..................... 108 Tactite Mineralization ......................... 108 Veinlet Mineralization ............................... 109 Comparison With Porphyry Copper Model................. Ill 8. CONCLUSIONS ....... 116 REFERENCES ..................................... 117 LIST OF ILLUSTRATIONS Figure Page 1. Index Map of Southeastern Arizona . ................. in pocket 2. Geologic Map of the Granite Peak. Stock Area, Whetstone Mountains, Arizona. ....................... in pocket 3. Significant Stratigraphic Sections in the Whetstone Mountains and Nearby Areas.................in pocket 4. Diagrammatic Cross-Sections of the Granite Peak Stock Area, Whetstone Mountains, Arizona . .in pocket 5. Drill Hole Log and Assay Cross-Sections, Granite Peak Stock Area, Whetstone Mountains, Arizona .... in pocket 6. Aerial Photograph of the Granite Peak Area................... 13 7. Granodiorite Contact with Rhyodacite......................... 37 8. Quartz Gabbro Contact with Overturned Shellenberger Canyon Formation............................... 42 9. Quartz Gabbro Contact with Shellenberger Canyon Formation.......................................... 43 10. Quartz Gabbro Xenolith in Granodiorite....................... 44 11. Quartz Gabbro Clots in Granodiorite ......................... 45 12. Photomicrograph of a Thin Section of Quartz Gabbro.......... 47 13. Massive Granodiorite.......................................... 50 14. Photomicrograph of a Thin Section of Granodiorite.......... 53 15. Granitization of Shellenberger Canyon Formation Near Granodiorite Contact ............................... 56 16. Alaskite Porphyry Xenolith in Granodiorite............ 61 17. Photomicrograph of a Thin Section of Pinal Schist X e n o l i t h ................................................ 62 18. Mineralized Joints in Quartz Monzonite Porphyry .............. 67 19. Quartz Monzonite Porphyry Contact with Granodiorite ........ 68 vii viii LIST OF ILLUSTRATIONS— Continued Figure Page 20.

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