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The geologic history of supergene enrichment in the porphyry copper deposits of southwestern North America. Item Type text; Dissertation-Reproduction (electronic) Authors Cook, Sterling Smith, III. 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 06/10/2021 10:28:29 Link to Item http://hdl.handle.net/10150/187012 INFORMATION TO USERS This manuscript .has been reproduced from the microfilm master. UMI films the text directly from the original or copy submitted. Thus, some thesis and dissenation copies are in typewriter face, while others may be from any type of computer printer. The quality of this reproduction is dependent upon the quality of the copy submitted. 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Contact UMI directly to order. UMI A Bell & Howellinformalion Company 300 North Zeeb Road. Ann Arbor. MI4S106-1346 USA 313/761-4700 800:521-0600 THE GEOLOGIC HISTORY OF SUPERGENE ENRICHMENT IN THE PORPHYRY COPPER DEPOSITS OF SOUTHWESTERN NORTH AMERICA by Sterling Smith Cook III 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 1 994 OMI Number: 9527976 OMI Microform 9527976 Copyright 1995, by OMI Company. All rights reserved. This microform edition is protected against unauthorized copying under Title 17, United States Code. UMI 300 North Zeeb Road Ann Arbor, MI 48103 2 THE UNIVERSITY OF ARIZONA GRADUATE COLLEGE As members of the Final Examination Committee, we certify that we have read the dissertation prepared by Sterling Smith Cook III entitled The Geologic History of supergene Enrichment in the Porphyry Copper Deposits of Southwestern North America and recommend that it be accepted as fulfilling the dissertation for the Degree of Doctor of Philosophy Date .D.ec zc: /9Py Date Date Date Final approval and acceptance of this dissertation is contingent upon the candidate's submission of the final copy of the dissertation to the Graduate College. I hereby certify that I have read this dissertation prepared under my direction and recommend that it be accepted as fulfilling the dissertation requ~ent~ k! .It /) .. AJ 'p{I Di~on Director ~ ~D~a~t~e~~~~~~--- Spencer R. Titley 3 STATEMENT BY AUTHOR This thesis 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 allowable without special permission, provided that accurate acknowledgement of source is made. Requests 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 department or the Dean of the Graduate College when in his or her 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. 4 ACKNOWLEDGEMENTS This work was made possible by the generous support of Phelps Dodge Mining Company. Without the encouragement and funding provided by Dr. John D. Forrester and Dr. William H. Wilkinson my dream of completing this dissertation would never have been realized. I am grateful to these gentlemen, my colleagues at Phelps Dodge, and anticipate with pleasure the many years of stimulating and productive work which lie ahead. I also wish to acknowledge the inspiration and support of Dr. Mark Barton, The University of Arizona and Dr. Mark Reed, University of Oregon. Dr. Barton always helped me find reasons to continue when the pressures of family and professional life made my academic progress so slow. Dr. Reed, my thesis advisor at the University of Oregon, encouraged me to return to Arizona and "become an expert on supergene enrichment". Gentlemen, thank you. 5 DEDICATION I dedicate this dissertation to the memory of two elegant authors of natural history, Sidney Paige and Fredrick Leslie Ransome. Many of the theories I have tried to elaborate or prove to the best of my knowledge first entered the geologic literature from the pens of these two great scientists. They are my inspirational forefathers. I also dedicate this dissertation to the hope that the Southwestern tradition of excellence in economic geology founded by men like S. Paige and F.L. Ransome and continued under the stewardship of men like S.R. Titley and J.S. Sumner will, in the future, continue to flourish and not be diminished by the vagaries of academic fashion. It is a privilege to be part of this tradition. 6 TABLE OF CONTENTS I. LIST OF ILLUSTRATIONS. 8 II. LIST OF TABLES. .. 10 III. INTRODUCTION ....................................... 13 IV. PREVIOUS WORK .................................... " 20 Leached Outcrops ................................ " 20 The Age of Enrichment. .. 21 Enrichment and the Evolution of Landscapes........ 23 V. METHODS OF INVESTIGATION ........................... 27 Field Work. .. 27 Geochronology ................................... " 28 Stability Relations of Alunite and Jarosite ..... 29 Supergene Origin of Alunite and Jarosite..... ... 29 K-Ar Dating of Submicron Illites................ 32 Interpretation of Dates. .. 36 VI. MODELS OF SUPERGENE ENRICHMENT. .. 38 VII. REGIONAL STRATIGRAPHIC SETTING ..................... 49 Paleocene to Early Eocene......................... 49 Late Eocene to Early Oligocene.................... 50 Late Oligocene. .. 51 Miocene-Pliocene ................................ " 52 Pleistocene-Recent. .. 53 VIII. DEPOSIT DESCRIPTIONS .............................. 55 Tyrone, New Mexico ............................... 56 Santa Rita, New Mexico ........................... 67 Morenci, Arizona ................................. 76 Safford District, Arizona ........................ 88 Bisbee, Arizona .................................. 90 San Manuel, Arizona .............................. 98 Pinto Valley - Castle Dome, Arizona .............. 104 San Xavier North, Pima District, Arizona ......... 106 Pima District .................................... 110 Red Mountain, Harshaw District, Arizona .......... 115 Silver Bell, Arizona ............................. 117 Lakeshore, Arizona ............................... 123 Sacaton, Arizona .................................. 127 Poston Butte - Florence, Arizona ................. 128 Aj 0, Arizona ..................................... 129 7 TABLE OF CONTENTS - Continued IX. DISCUSSION ......................................... 134 Regional Cycles of Weathering and Enrichment ...... 134 The Duration of Enrichment Events ................ , 147 A Trans-Cordilleran Pattern? ..................... 150 X. CONCLUSIONS ........................................ 153 XI. REFERENCES ......................................... 155 8 LIST OF FIGURES Figure 1: Map of Porphyry Copper Deposits in Southwestern North America. .. 15 Figure 2 : Cenozoic Sedimentary Assemblages in the Basin and Range Province. .. 19 Figure 3 : The Anderson (1982) Model of Multicycle Weathering and Enrichment ..................... 40 Figure 4 : An Idealized Model of Multicycle Weathering and Enrichment. .. 43 Figure 5: An Idealized Paragenesis Diagram for Mulitcycle Weathering and Enrichment. .. 48 Figure 6 : Cenozoic Stratigraphy near Silver City, southwestern New Mexico ....................... 58 Figure 7 : Longitudinal Section Through the Tyrone Chalcocite Deposit. .. 62 Figure 8 : Geologic Cross Section Through the Tyrone Chalcocite Deposit.. ....... ............ 64 Figure 9 : East-West Geologic Cross Section Through the Southern Part of the Santa Rita Deposit. .. 70 Figure 10: North-South Geologic Cross Section Through the Southern Part of the Santa Rita Deposit. .. 73 Figure 11: Cenozoic Stratigraphy in the Safford- Morenci Area, Eastern Arizona. .. 79 Figure 12: Geologic Sketch Map of the Morenci District. .. 82 Figure 13: Geologic Cross Section Through the Morenci Chalcocite Deposit........ ............ 84 Figure 14 : Geologic Cross Section Through the Chalcocite Blanket at Bisbee. .. 94 Figure 15: Diagramatic Cross Sections Illustrating the History of Supergene Enrichment at Bisbee. .. 97 Figure 16: Cenozoic Stratigraphy in the Miami- Globe Area, Central Arizona ................... 100 Figure 17: Geologic Cross Section

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