f -.. GUIDEBOOK SERIES Volume 30
GOLD DEPOSITS OF NORTHERN SONORA, MEXICO r " [ Edited by K.F. Clark
WHY \' ~ .... ARIZONA
EITiro ~ ~ Cerro Colorado
SONORA f "' l .. .J
lWiJ2::.:::1':J?l. Presa • -~/Novil/o \ ~! : • JONOCHI ) :a:.. S! I l j Guidebook Prepared for the Society of Economic Geologists Field Conference-19-24 October 1998
Series Editor: Tommy B. Thompson SOCIETY OF ECONOMIC GEOLOGISTS CONTENTS
Page
Preface iii
Acknowledgments and Dedication ...... iv
Itinerary ...... v l Route Map ...... ·...... vi FIRST DAY . 1 ! Road Log from Tucson to Nogales, Arizona, and Magdalena de Kino via Santa Gertrudis Mine, Sonora by Kenneth F. Clark ...... 1
Current Situation and Prospectives of the Santa Gertrudis Mining District, Municipality of Cucurpe, Sonora by Jesus A. Alba. Pascoe ...... 21
SECOND DAY Road Log to Lluvia de Oro and San Francisco Mines via Magdalena de Kino and Santa Ana, Sonora by Kenneth F. Clark ...... 35
Geology, Alteration, and Mineralization of the Lluvia de Oro Gold Deposit by Pedro I. Teran Cruz ...... 41
Geology, and Mineralization of the San Francisco Gold Deposit by Hector Araiza Martinez ...... 49
THIRD DAY Road Log from Magdalena de Kino to El Tiro Placer Mine, Cerro Colorado and Hermosillo, Sonora by Kenneth F. Clark ...... 59
Quartz and Placer Gold Deposits in Northwestern Mexico (reprinted from J.R. Southworth) ...... 71
Cerro Colorado Project by Peter J. Clarke 73
FOURTH DAY Road Log from Hermosillo to Caborca via La Colorado Mine and Santa Ana, Sonora by Cesar Jacques Ayala and Kenneth F. Clark ...... 79
La Colorada Mine, Sonora, Mexico by Ross D. Zawada ...... 87
Stratigraphy of the Cerros El Amol, Altar, Sonora, Mexico; by Juan Carlos Garcia y Barragan, Cesar Jacques Ayala, and Kees A. DeJong ...... 101
Vll FIFTH DAY r Road Log from Caborca to La He~radura and La Choya Mines, and Sonoyta, Sonora, and Return to Tucson, Arizona by Kenneth F. Clark ...... 117 r L Geology of La Herradura Gold Deposit, Caborca, Sonora, Mexico; by V. de Ia Garza, B. Noguez, I. Novelo, and J. Mayor ...... 133 j'l\1 L I Geology and Operation of La Choya Open-Pit Heap-Leach Mine; by A. H. Summers V., A. Mendivil V., and G. A. Hufford ...... 149
Exploration and Geology of the Choya Sur Gold Deposit, Sonora, Mexico by John A. Thoms ...... 157 E Structure and Kinematics along A Jurassic Plate Boundary Transform, the Mojave-Sonora Megashear, Northwestern Sonora, Mexico by Patricia L. Campbell and Thomas H. Anderson ...... 177
Paleomagnetic Reconstruction in Northern Sonora by Roberto Molina and John W. Geissman ...... 187
Lithology, Structure and Gold Deposits of Northwestern Mexico by Cesar Jacques Ayala and Kenneth F. Clark ...... 203
LIST OF PARTICIPANTS...... 249 nu SPANISH-ENGLISH GEOLOGICAL AND MINING TERMS ...... 252 c r u>
viii