A Guide to the Geology of the Sedona & Oak Creek Canyon Area, Arizona
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A Guide to the Geology of the SEDONA & OAK CREEK CANYON AREA, ARIZONA ARIZONA GEOLOGICAL SURVEY Down John V. Bezy -to- 20Earth SATELLITE IMAGE OF THE VERDE VALLEY D C EDONA & OAK CREEK B S CANYON AREA, ARIZONA E A F H G I J A) Mormon Lake B) Upper Lake Mary C) Flagstaff K D) Mount Elden E) Oak Creek Canyon F) Sedona G) House Mountain H) Tuzigoot National Monument I) Cottonwood J) Verde River K) Camp Verde A Guide to the Geology of the SEDONA & OAK CREEK CANYON AREA, ARIZONA John V. Bezy ARIZONA GEOLOGICAL SURVEY Down -to- 20Earth Copyright © 2012, Arizona Geological Survey All rights reserved Photos: John Bezy unless otherwise noted Front cover photo by: Dr. Larry D. Fellows Book design: Arnie Bermudez Copyright Printed in the United States of America Permission is granted for individuals to make single copies for personal use in research, study, or teaching, and to use short quotes, figures, or tables, from this publication for inclusion in scientific books and journals, provided that the source of the information is appropriately cited. This consent does not extend to other kinds of copying for general distribution, for advertising or promotional purposes, for creating new or collective works, or for resale. The reproduction of multiple copies and the use of articles or extracts for commercial purposes require written permission from the Arizona Geological Survey. Published by The Arizona Geological Survey 416 W Congress, #100, Tucson, AZ 85701 (520) 770-3500 www.azgs.az.gov i Acknowledgements he author expresses sincere gratitude to Drs. Lee Allison, Mike Conway, Jon E. Spencer, and Steven TRauzi (Arizona Geological Survey) and Dr. Arthur S. Trevena, for technical review of this publication. Appreciation is also extended to AZGS editor Dr. Mike Conway for editorial review. Special thanks are due to Dr. Larry D. Fellows (former Director, Arizona Geological Survey for help with the planning of this publication and a number of the photographs that grace its pages. Dr. Fellows also brought the Cathedral Butte volcanic plug to our attention and suggested that we include it in this guidebook. Dr. Steven Rauzi (Arizona Geological Survey) provided valuable insight regarding the Supai Group. Dr. John Dohrenwend graciously granted permission to use his satellite images in this publication. Poster sized satellite image maps (1:100,000 scale) of the Sedona-Oak Creek region may be ordered from John Dohrenwend, P.O. Box 1467, Moab Utah 84532--1467, phone (866) 230-8941, Email: dohrenwend@ rkymtnhi.com. Thanks are extended to Superintendent Kathy Davis and Park Ranger Dennis Casper for providing a satellite image of Tuzigoot National Monument, and to the Park Manager of Slide Rock State Park for permitting the use of Figure 3.1. Mr. Arnie Bermudez deserves special thanks for the many hours he devoted to designing this publication. This publication would not have been possible without the professional support of Drs. Lee Allison (Director, Arizona Geological Survey) and Mike Conway (Geologic Extension Service, Arizona Geological Survey). ii Preface Acknowledgements Introduction General Geology of the Sedona-Oak Creek Canyon area Geologic Features Along Highway 89A North of Sedona Feature 1. Talus Page 6 Contents Feature 2. Supai Group Page 7 Feature 3. Normal fault Page 8 Feature 4. Flood-cut bedrock channel Page 9 Feature 5. Coconino Sandstone Page 10 Feature 6. Rock varnish Page 11-12 Feature 7. Kaibab and Toroweap Formations Page 13 Feature 8. Neogene Basalt Page 14 Geologic Features Along Highway 179 and Road 78 South of Sedona Feature 9. Joints and pinnacles Page 16 Feature 10. Volcanic plug and dike Page 17 Feature 11. Tinajas Page 18 Feature 12. Sinkhole Page 19 Feature 13. Bedding plane weathering Page 20 Feature 14. Shield volcano Page 21 Geologic Features Along Highway 89A Southwest of Sedona Feature 15. Cobble-capped terrace remnants Page 23 Feature 16. Entrenched meanders Page 24 Feature 17. Verde Formation Page 25 Feature 18. Stream terraces Page 26 Feature 19. Entrenched cut-off meander loop Page 27 Geologic Features Along Forest Service Roads 152 (Dry Creek Road), 152C, 795 and 525 Northwest of Sedona Feature 20. Case Hardening Page 29 Feature 21. Alcove Page 30 Feature 22. Slab-failure Page 31 Feature 23. Mineral stains along joints Page 32 Feature 24. Cross-bedding Page 33 iii Suggested Readings Contents List of Figures Figure A Geologic features and access road in the Sedona-Oak Creek area. Figure B The Colorado Plateau, the Transition Zone, and the Basin and Range Province of north-central Arizona. Figure C The Mogollon Rim north of Sedona, Arizona. Figure D Geologic map of the Sedona-Oak Creek area. Figure 1.1 Talus east of Encinoso Picnic Area, Oak Creek Canyon. Figure 2.1 Sandstones of the Supai Group and overlying Coconino Formation at Slide Rock State Park. Figure 3.1 Geologic cross section of Oak Creek Canyon at Slide Rock State Park showing the offset of rock layers east and west of the Oak Creek Fault. Figure 3.2 Nearly vertical beds of once-horizonal rock in the bed of Oak Creek, near Bootlegger Campground. Figure 4.1 Channel cut into the sandstone floor of Oak Creek Canyon by flash flooding. Figure 5.1 Cross-bedding in Coconino Sandstone along the Call of the Canyon trail, West Fork of Oak Creek. Figure 6.1 Rock varnish and lichens on Coconino Sandstone rock face, Call of the CanyonTrail, West Fork of Oak Creek. Figure 6.2 Streaks of rock varnish on cliff of Coconino Sandstone, Call of the Canyon Trail, West Fork of Oak Creek. Figure 7.1 The Kaibab and Toroweap Formations viewed from Oak Creek Vista, Highway 89A. Figure 8.1 Basalt below Oak Creek Vista, Highway 89A Figure 8.2 Columnar jointing in basalt rimrock above Oak Creek Canyon. Figure 9.1 Joints and pinnacles in the Supai Group, near Chapel of the Rocks. Figure 10.1 Volcanic plug injected into Supai Group sandstone at Cathedral Rock. Figure 10.2 Volcanic dike at Cathedral Rock. Figure 11.1 Tinajas cut into sandstone bed of small drainage, along the Broken Arrow Trail. Figure 12.1 Devil’s Dining Room sinkhole. Figure 12.2 Block diagrams illustrating the formation of the Devil’s Dining Room sinkhole. Figure 13.1 Aligned niches in sandstones and siltstones caused by weathering along bedding planes. Figure 14.1 House Mountain shield volcano. Figure 15.1 Sand and rounded pebbles and cobbles capping Airport Mesa. Figure 16.1 Satellite image of entrenched meanders in Oak Creek Canyon near Red Rocks State Park. Figure 16.2 Block diagrams illustrating the development of entrenched meanders. Figure 17.1 Limestones of the Verde Formation exposed along the Verde River Valley. Figure 18.1 Stream terraces along the Verde River at Dead Horse State Park. Figure 18.2 Block diagrams illustrating the formation of stream terraces. Figure 19.1 Entrenched cut-off meander loop along the Verde River at Tuzigoot National Monument. Figure 19.2 Block diagrams illustrating the formation of an entrenched cut-off meander loop. Figure 20.1 Case hardened sandstone surface near Palatki Ruins. Figure 21.1 Alcove containing Palatki Ruins developed in Supai Group sandstone cliff. Figure 21.2 Block diagrams illustrating the formation of alcoves. Figure 22.1 Rock slab separated from cliff of Supai Group sandstone near Palatki Ruins. Figure 23.1 Mineral-stained sandstone surfaces along a joint near petrographs at Palatki Ruins. Figure 24.1 Cross-bedding in sandstone near Honanki Ruins. Figure 24.2 Block diagram illustrating the deposition of cross-beds in a dune or sand bar. iv Introduction Figure A. Geologic features and access roads in the Sedona-Oak Creek Area (numbered 1-24). 1 he Sedona-Oak Creek Canyon area offers some Locations of the geologic features and access roads Tof the most unique and spectacular geologic and trails are shown on Figure A. More detailed Introduction features in northern Arizona. Because of the relatively locations are provided in the text as needed. All of the sparse vegetation most of these features are easy to roads recommended for use can be driven with any recognize and photograph. vehicle of moderate clearance. Drainages are subject Some of these geologic features are common on to flash flooding during periods of heavy rainfall and the Colorado Plateau of northern Arizona, western should be crossed with caution. Restaurants, gasoline, Colorado, southern Utah, and northeastern New Mexico. information on road conditions, and emergency services Others occur in many other parts of the American are available in Sedona, Cottonwood, and the Village of Southwest. Oak Creek. This booklet is your field guide to the geology of Another purpose of this guide is to provide the this magnificent landscape of red rock pinnacles, reader with an understanding of the dynamic processes buttes, mesas and canyons. All of the geologic features that have shaped this exceptional landscape. You described in the text can be reached by short walks from will encounter many of the features discussed in the Highways 89A and 79, Road 78, and from U.S. Forest text again and again as you continue to explore the Service roads. This booklet is written for the visitor who Southwest. I hope that your experience in the Sedona- has an interest in geology, but who may not have had Oak Creek Canyon area will enhance the pleasure of formal training in the subject. It may also help assure those explorations. that the visiting geologist does not overlook some of The Supai Group has been divided into formations the features described. by some geologists. For the purposes of this non- To set the stage, I have briefly described the area’s technical publication the traditional name Supai Group geologic setting and history.