The geology of the west central portion of the Patagonia Mountains, Santa Cruz County, Arizona Item Type text; Thesis-Reproduction (electronic); maps Authors Moger, Seth Raynor, 1937- 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 02/10/2021 18:29:38 Link to Item http://hdl.handle.net/10150/550398 THE GEOLOGY OF THE WEST CENTRAL PORTION OF THE PATAGONIA MOUNTAINS, SANTA CRUZ COUNTY, ARIZONA by . Seth Raynor Moger A Thesis Submitted to the Faculty of the DEPARTMENT OF GEOLOGY In Partial Fulfillment of the Requirements For the Degree of MASTER OF SCIENCE In the Graduate College THE UNIVERSITY OF ARIZONA 19 6 9 STATEMENT BY AUTHOR This thesis has been submitted in partial fulfillment of re­ quirements 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. 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 judg­ ment the proposed use of the material is in the interests of scholar­ ship. In all other instances, however, permission must be obtained from the author. SIGNED: APPROVAL BY THESIS DIRECTOR This thesis has been approved on the date shown below: Professor of Geology ACKNOWLEDGMENTS The writer wishes to thank Dr. S. R. Titley for his supervision and constructive criticism throughout the preparation of this thesis. I am also especially appreciative to Dr. Peter Price and Dr. C. P. Jenney, consulting geologists, Ontario, Canada, for allowing me to complete my field work while.being employed by West Range Company, Tucson, A rizona. The author is grateful to Fred Graybeal for his encouragement and helpful suggestions during the writing of this thesis and also wishes to thank Paul Handverger and Michael Wood for their aid in the field and laboratory. I am deeply appreciative to my wife Paula for her continued inspiration and support without which I would not have been able to complete this thesis. iii TABLE OF CONTENTS Page LIST OF ILLUSTRATIONS................................................................................ vi LIST OF TA BLES...................................................................... vii ABSTRACT.......................................... viii INTRODUCTION . .......................................................... 1 Location and Extent of A r e a .................................................................. 1 T o p o g ra p h y .................................................................................................. 1 C lim ate and V e g e ta tio n ........................................................................... 1 Purpose of I n v e s t ig a ti o n ...................................................................... 3 Method of Investigation . •............................................................. 4 Previous Work ......................................................................................... 4 IGNEOUS ROCKS.................................................................................................. 6 D io r ite ............................................................................................................ 6 Description .............................................. 6 P e tro g ra p h y ........................................................ 7 Quartz M onzonite .................................................................................... 10 Description ..................................... 10 P e tro g ra p h y ......................................................................................... 11 S y e n o d i o r it e .............................................................................................. 15 D e s c rip tio n ......................................................................................... 15 P e tro g ra p h y ......................................................................................... 15 G ra n ite ............................................................................................................ 18 D e s c rip tio n ......................................................................................... 18 Petrography .............................................. 18 G r a n o d i o r i t e .............................................................................................. 21 D e s c rip tio n ......................................................................................... 21 Petrography ......................................................................................... 21 P e tro lo g y ...................................................................................................... 22 D a t a .................................................................................... 23 Harker Variation D iagram ........................... 23 ACF D i a g r a m ........................................................................... 25 Modal D i a g r a m ....................................................................... 27 Field Evidence Relating to the Origin of the Igneous R o c k s .................................................................. 27 I n te r p r e ta tio n ................................................................. 30 iv V TABLE OF CONTENTS—Continued Page STRUCTURE . .............................................................................................. 32 Types and Distribution ................................................................. .... 32 Structural P a tte r n s ................................................................. 33 Origin and Movement of Structures . ............................ 36 ECONOMIC GEOLOGY ......................................... 44 G eneral H istory of the A r e a .................................................................. 44 General Mineralization of the A rea ................................................... 44 Areal A lteration ..................................... 47 Mines and Prospects ................................... 50 Sonoita M i n e .................................................................................... 50 Robert E. Lee Mine . .................................................................. 51 Tres de Mayo G roup .......................................... • ......................... 52 Jarillas M ine .......................................... ' ...................................... 52 D enver M i n e .......................................................................... 53 O 'M aras M in e .................................................................................... 53 O ther Areas of M in e ra liz a tio n ............................................................. 54 B re c c ia ............................................................................................................ 55 Control of M in e ra liz a tio n ...................................................................... 56 Origin of M in e r a liz a tio n ........................................................................... 57 Economic Potential......................................... 57 REFERENCES C I T E D ............................................................................................. 59 SELECTED BIBLIOGRAPHY 61 LIST OF ILLUSTRATIONS Figure ' Page 1. Index Map Showing Location of Thesis Area in Patagonia Mountains, Santa Cruz County, A r iz o n a ................................................................................... 2 2. Geologic Map of the West Central Portion of the Patagonia Mountains, Santa Cruz County, A r iz o n a ............................ .... ................................................... in pocket 3. B arker Variation D iagram ....................................................... 24 4. ACF Diagram Showing Nock old s' Averages as Compared to Similar Rock Types in the Patagonia M o u n ta in s ....................................................... 26 5. Diagram Showing Modal Percentages of Quartz, Plagioclase, and Orthoclase in Thin Sections of Thesis Rocks . ....................................................................... 28 6. Structure and Alteration Map of the West Central Portion of the Patagonia Mountains, Santa Cruz C ounty, A riz o n a ................................................... in pocket 7. Rose Diagram Showing All Fractures in Thesis Area. 34 8. Sketch Map Showing Structural Trends from Aerial . Photographs, Patagonia Mountains, Arizona .......... 35 9. Rose Diagram Showing Barren and Mineralized Fractures East of the Front Range F a u lt ............................ ' 37 10. Rose Diagram Showing Barren and Mineralized Fractures W est of the Front Range F a u l t ................. 38 11. Contour Diagram Showing Barren Fractures in Thesis Area, Patagonia Mountains, Arizona..... 39 12. Contour Diagram Showing Mineralized Fractures in Thesis Area, Patagonia Mountains, Arizona .... 40 13. Sketch Map Showing Metal Distribution in Mines Around the Laramide Intrusion, Patagonia