THIS VOLUME IS DEDICATED TO WARREN B. HAMILTON For his pioneering work on Mesozoic Compressional Tectonics in the Colorado River area. LIST OF CONTRIBUTORS J. Lawford Anderson Derrick D. Hirsch Christopher J. Natenstedt Richard L. Armstrong Thomas D. Hoisch Robert J. Knipe Rachel Baltz Keith A. Howard James K. Otton Gary M. Beckerman Mary Hume Martha A. Pernokas Lindee Berg Richard W. Hurst Jan-Claire Phillips J. P. Calzia Barbara E. John J. E. N. Pike Christy Craig Michael R. Jorgensen Cynthia L. Pridmore Jerry B. Dahm Douglas P. Klein William A. Rehrig Gregory A. Davis Valerie A. Krass Stephen J. Reynolds M. Jane Ellis Daniel Krummenacher Stephen M. Richard William S. Emerson Gregory Leveille James Ridenour Douglas J. English Richard A. LeVeque Jamie P. Robinson Eric G. Frost Robert E. Logan Eugene I. Smith Welford E. Garner John H. Lyle Jon E. Spencer Pattie Geis Donna L. Martin Paul Stone Mark P. Germinario Richard F. Marvin Susan E. Tanges John W. Goodge John E. Marzolf Derrick B. Teel Warren W. Gross Randall S. Mathis Linda C. Thurn James T. Gutmann William C. McClelland Richard M. Tosdal Warren Hamilton Michael McCurray Phillip t'~. Trumbly David D. Hankins Calvin F. Miller Ryan D. Turner V. L. Hansen David M. Miller Robert D. Wallace Lucy E. Harding Phillip R. Moyle Joe Wilkins, Jr. Gordon Haxel Karl J. Mueller Spencee L. Willett Tom L. Heidrick Kent Murray William R. Wood F. L. "Bud" Hillemeyer John K. Nakata Richard A. Young THIS VOLUME IS DEDICATED TO R. ERNEST ANDERSON For his pioneering work on Tertiary Extensional Tectonics in the Colorado River area. Table of Contents STRUCTURAL EVOLUTION OF THE BIG MARIA MOUNTAINS, NORTHEASTERN RIVERSIDE COUNTY, SOUTHEASTERN CALIFORNIA Warren Hamilton PALEOGEOMORPHOLOGIC EVIDENCE FOR THE STRUCTURAL HISTORY OF THE COLORADO PLATEAU MARGIN IN WESTERN ARIZONA Richard A. Young 29 GEOLOGY AND GEOCHEMISTRY OF THE VOLCANIC ROCKS IN THE RIVER MOUNTAINS, CLARK COUN­ TY, NEVADA AND COMPARISONS WITH VOLCANIC ROCKS IN NEARBY AREAS Eugene I. Smith 41 THE MULE MOUNTAINS THRUST IN THE MULE MOUNTAINS CALIFORNIA AND ITS PROBABLE EXTEN­ SION IN THE SOUTHERN DOME ROCK MOUNTAINS, ARIZONA; A PRELIMINARY REPORT Richard M. Tosdal 55 REGIONAL GRAVITY AND MAGNETIC EVIDENCE FOR A TECTONIC WEAKNESS ACROSS SOUTHWESTERN ARIZONA Douglas P. Klein 61 MINERAL OCCURRENCES IN THE WHIPPLE MOUNTAINS WILDERNESS STUDY AREA, SAN BERNAR- DINO COUNTY, CALIFORNIA james Ridenour, Phillip R. Moyle, and Spencee L. Willett 69 TECTONIC IMPLICATIONS OF CENOZOIC VOLCANISM IN SOUTHEASTERN CALIFORNIA Kent Murray 77 PRELIMINARY REPORT ON DIKING EVENTS IN THE MOHAVE MOUNTAINS, ARIZONA john K. Nakata 85 COMPLEX TERTIARY STRATIGRAPHY AND STRUCTURE, MOHAVE MOUNTAINS, ARIZONA: A PRELIMINARY REPORT J.E.N. Pike and V.L. Hansen 91 DIKE SWARMS AND LOW-ANGLE FAULTS, HOMER MOUNTAIN AND THE NORTHWESTERN SACRA- MENTO MOUNTAINS, SOUTHEASTERN CALIFORNIA Jon E. Spencer and Ryan D. Turner 97 CHARACTER AND ORIGIN OF CATACLASITE DEVELOPED ALONG THE LOW-ANGLE WHIPPLE DETACH­ MENT FAULT, WHIPPLE MOUNTAINS, CALIFORNIA Jan-Claire Phillips 109 GEOLOGY AND REGIONAL SETTING OF THE CASTLE DOME MOUNTAINS, SOUTHWESTERN ARIZONA James T. Gutmann 117 ORIGIN OF FOLDS OF TERTIARY LOW-ANGLE FAULT SURFACES, SOUTHEASTERN CALIFORNIA AND WESTERN ARIZONA jon E. Spencer 123 A PROGRESS REPORT ON THE TECTONIC SIGNIFICANCE OF THE MCCOY MOUNTAINS FORMATION, SOUTHEASTERN CALIFORNIA AND SOUTHWESTERN ARIZONA Lucy H. Harding 135 MULTIPLE DEFORMATION IN THE HARCUVAR AND HARQUAHALA MOUNTAINS, WEST-CENTRAL ARIZONA Stephen J. Reynolds 137 TERTIARY EXTENSIONAL TECTONICS AND ASSOCIATED VOLCANISM IN WEST-CENTRAL ARIZONA James K. Otton 143 MID-TERTIARY DETACHMENT FAULTING AND MINERALIZATION IN THE TRIGO MOUNTAINS, YUMA COUNTY, ARIZONA Welford E. Garner, Eric G. Frost, Susan E. Tanges, and Mark P. Germinario 158 GEOLOGY OF GRANODIORITE IN THE COXCOMB MOUNTAINS, SOUTHEASTERN CALIFORNIA J.P. Calzia 173 BASE AND PRECIOUS METAL MINERALIZATION RELATED TO LOW-ANGLE TECTONIC FEATURES IN THE WHIPPLE MOUNTAINS, CALIFORNIA AND BUCKSKIN MOUNTAINS, ARIZONA Joe Wilkins, Jr. and Tom L. Heidrick 182 THE TEUTONIA BATHOLITH: A LARGE INTRUSIVE COMPLEX OF JURASSIC AND CRETACEOUS AGE IN THE EASTERN MOJAVE DESERT, CALIFORNIA Gary M. Beckerman, Jamie P Robinson, and J. Lawford Anderson 205 STRUCTURAL ANALYSIS OF THE BIG MARIA MOUNTAINS, RIVERSIDE COUNTY, CALIFORNIA M. Jane Ellis 222 PRELIMINARY REPORT ON THE STRUCTURE AND STRATIGRAPHY OF THE SOUTHERN LITTLE HAR- QUAHALA MOUNTAINS, YUMA COUNTY, ARIZONA Stephen M. Richard 235 GEOLOGIC DEVELOPMENT AND LATE MESOZOIC DEFORMATION OF THE LITTLE MARIA MOUNTAINS, RIVERSIDE COUNTY, CALIFORNIA William S. Emerson 245 GEOMETRIC ANALYSIS OF UPPER-PLATE FAULT PATTERNS IN THE WHIPPLE-BUCKSKIN DETACHMENT TERRANE Warren W. Gross and F.L. "Bud" Hillemeyer 256 STRATIGRAPHY AND STRUCTURE OF THE PALEN FORMATION, PALEN MOUNTAINS, SOUTHEASTERN CALIFORNIA Richard A. LeVeque 267 SYNOROGENIC EVOLUTION OF THE COPPER BASIN FORMATION IN THE EASTERN WHIPPLE MOUN- TAINS, SAN BERNARDINO COUNTY, CALIFORNIA Derrick B. Teel and Eric G. Frost 275 THE PETROLOGIC AND TECTONIC EVOLUTION OF VOLCANIC ROCKS IN THE SOUTHERN CALIFORNIA BORDERLAND: A TRANSITIONAL TECTONIC ENVIRONMENT Richard W, Hurst, William R, Wood, and Mary Hume 287 MID-TERTIARY DETACHMENT FAULTING AND MANGANESE MINERALIZATION IN THE MIDWAY MOUN- TAINS, IMPERIAL COUNTY, CALIFORNIA Lindee Berg, Gregory Leveille, and Pattie Geis 298 POSSIBLE RELATIONSHIP BETWEEN MIOCENE CRUSTAL EXTENSION/DETACHMENT FAULTING AND THE DEPOSITION OF THE TOLBARD FANGLOMERATE IN THE MIDWAY AND WESTERN PALO VERDE MOUNTAINS, IMPERIAL COUNTY, CALIFORNIA Michael R, Jorgensen, Christopher J, Natenstedt and Phillip N, Trumbly 313 GEOLOGIC FRAMEWORK OF THE CHEMEHUEVI MOUNTAINS, SOUTHEASTERN CALIFORNIA Barbara E, John 317 MID-TERTIARY DETACHMENT FAULTING IN THE SOUTHEASTERN NEWBERRY MOUNTAINS, CLARK COUNTY, NEVADA Randall S, Mathis 326 GEOLOGIC AND GEOCHRONOLOGIC RECONNAISSANCE OF THE TURTLE MOUNTAINS AREA, CALIFORNIA: WEST BORDER OF THE WHIPPLE MOUNTAINS DETACHMENT TERRANE Keith A Howard, Paul Stone, Martha A Pernokas, and Richard F. Marvin 341 UPPER-PLATE STRUCTURE AND SEDIMENTATION OF THE BAKER PEAKS AREA, YUMA COUNTY, ARIZONA Cynthia L. Pridmore and Christy Craig 356 DETACHED CRYSTALLINE ROCKS OF THE MOHAVE, BUCK, AND BILL WILLIAMS MOUNTAINS, WESTERN ARIZONA Keith A. Howard, John W. Goodge, and Barbara E. John 377 CRYSTALLINE TERRANES OF THE BOWMAN'S WASH AREA OF THE WHIPPLE MOUNTAINS Valerie A Krass 393 STRUCTURAL GEOLOGY OF THE CENTRAL SACRAMENTO MOUNTAINS, SAN BERNARDINO COUNTY, CALIFORNIA William C. McClelland 401 GEOLOGIC AND GEOCHRONOLOGIC RELATIONS IN THE LOWER PLATE OF THE WHIPPLE DETACH­ MENT FAULT, WHIPPLE MOUNTAINS, SOUTHEASTERN CALIFORNIA: A PROGRESS REPORT Gregory A Davis, J. Lawford Anderson, Donna L. Martin, Daniel Krummenacher, Eric G. Frost, and Richard L. Armstrong 408 THE GEOLOGY OF A LATE MIOCENE SILICIC VOLCANIC CENTER IN THE WOODS AND HACKBERRY MOUNTAINS AREA OF THE EASTERN MOJAVE DESERT, SAN BERNARDINO COUNTY, CALIFORNIA Michael McCurry 433 REGIONAL CHARACTER OF MYLONITIC GNEISS IN THE CADIZ VALLEY AREA, SOUTHEASTERN CALIFORNIA Keith A. Howard, David M, Miller, and Barbara E. John 441 MID-TERTIARY DETACHMENT FAULTING IN THE MOHAWK MOUNTAINS OF SOUTHWESTERN ARIZONA Karl J. Mueller, Eric G. Frost, and Gordon Haxel 448 PRELIMINARY GEOLOGY OF A PORTION OF THE SOUTHERN KOFA MOUNTAINS, YUMA COUNTY, ARIZONA Jerry B. Dahm and David D. Hankins 459 INTERRELATIONSHIP OF LATE MESOZOIC THRUST FAULTING AND MID-TERTIARY DETACHMENT FAULTING IN THE RIVERSIDE MOUNTAINS, SOUTHEASTERN CALIFORNIA John H. Lyle 470 PALEOGEOGRAPHIC IMPLICATIONS OF THE EARLY JURASSIC (?) NAVAJO AND AZTEC SANDSTONES John E. Marzolf 493 EVALUATION OF POSSIBLE DETACHMENT FAULTING WEST OF THE SAN ANDREAS, SOUTHERN SANTA ROSA MOUNTAINS, CALIFORNIA Robert D. Wallace and Douglas J. English 502 INTERPRETATION OF AGE RELATIONSHIPS AND DEFORMATIONAL HISTORY, SOUTHEASTERN WHIP­ PLE MOUNTAINS, CALIFORNIA Linda C. Thurn 511 K-Ar GEOCHRONOLOGIC RECORD OF MESOZOIC AND TERTIARY TECTONICS OF THE BIG MARIA- LITTLE MARIA-RIVERSIDE MOUNTAINS TERRANE Donna L. Martin, Daniel Krummenacher, and Eric G. Frost 518 METAMORPHIC CORE COMPLEXES OF THE SOUTHWESTERN UNITED STATES - AN UPDATED ANALYSIS William A Rehrig 551 MESOZOIC THRUSTING, METAMORPHISM, AND PLUTONISM, OLD WOMAN-PI UTE RANGE, SOUTH- EASTERN CALIFORNIA Calvin F. Miller, Keith A Howard, and Thomas D. Hoisch 561 LATE MESOZOIC FOLDING AND THRUSTING AND TERTIARY EXTENSIONAL FAULTING IN THE ARICA MOUNTAINS, RIVERSIDE COUNTY, CALIFORNIA Rachel Baltz 582 GEOMETRY OF DETACHMENT FAULTING AND DIKE EMPLACEMENT IN THE SOUTHWESTERN CASTLE DOME MOUNTAINS, YUMA COUNTY, ARIZONA Robert E. Logan and Derrick D. Hirsch 598 INTERACTION OF FOOTWALL GEOMETRY AND FOLDS DEVELOPED DURING DETACHMENT FAULTING Robert J. Knipe 608 ACKNOWLEDGEMENTS We would like to thank many of the people that have been involved in bringing this volume to its final form. Foremost among these are three people who have kindled our scientific thought, interest, and direction. This volume is really an outgrowth of their research into the Colorado River area, which has brought many of the other workers into this terrane. For their years of teaching, guidance, and friendship, we would like to extend a very heart-felt thanks to Greg Davis, Lawford Anderson, and Daniel Krummenacher. Part of the motivation for bringing this volume together was to recognize the pioneering work of R. Ernest Anderson and Warren B. Hamilton in their studies of Tertiary extension and Mesozoic thrust faulting in the