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Isolated Carbonate Bodies Composed of Stacked Debris-Flow Deposits on a Fine-Grained Carbonate Lower Slope of Devonian Age, Antelope Peak, Elko County, Nevada

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Isolated Carbonate Bodies Composed of Stacked Debris-Flow Deposits on a Fine-Grained Carbonate Lower Slope of Devonian Age, Antelope Peak, Elko County, Nevada Isolated Carbonate Bodies Composed of Stacked Debris-Flow Deposits on a Fine-Grained Carbonate Lower Slope of Devonian Age, Antelope Peak, Elko County, Nevada U.S. GEOLOGICAL SURVEY BULLETIN 1988-E ".- -.' '.: - . .- ". ' : - ' ' ' ' .- -: '.' '-'' --'''''"''~'"""'"''' ''" AVAILABILITY OF BOOKS AND MAPS OF THE U.S. GEOLOGICAL SURVEY Instructions on ordering publications of the U.S. Geological Survey, along with prices of the last offerings, are given in the current-year issues of the monthly catalog "New Publications of the U.S. Geological Survey." Prices of available U.S. Geological Survey publications re­ leased prior to the current year are listed in the most recent annual "Price and Availability List." 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Subscriptions to periodicals (Earthquakes & Volcanoes and Preliminary Determination of Epicenters) can be obtained ONLY RESTON, Virginia-USGS National Center, Rm. 1C402, from the 12201 Sunrise Valley Dr. Superintendent of Documents SALT LAKE CITY, Utah-Federal Bldg., Rm. 8105, Government Printing Office 125 South State St. Washington, DC 20402 SPOKANE, Washington-U.S. Post Office Bldg., Rm. 135, (Check or money order must be payable to Superintendent of West 904 Riverside Ave. Documents.) WASHINGTON, D.C.-Main Interior Bldg., Rm. 2650, Maps 18th and C Sts., NW. For maps, address mail orders to Maps Only U S. Geological Survey, Map Distribution Maps may be purchased over the counter at the following Box 25286, Bldg. 810, Federal Center U.S. Geological Survey offices: Denver, CO 80225 Residents of Alaska may order maps from FAIRBANKS, Alaska-New Federal Bldg, 101 Twelfth Ave. U.S. Geological Survey, Earth Science Information Center ROLLA, Missouri-1400 Independence Rd. 101 Twelfth Ave., Box 12 Fairbanks, AK 99701 STENNIS SPACE CENTER, Mississippi-Bldg. 3101 Isolated Carbonate Bodies Composed of Stacked Debris-Flow Deposits on a Fine-Grained Carbonate Lower Slope of Devonian Age, Antelope Peak, Elko County, Nevada By Peter M. Sheehan, John M. Pandolfi, and Keith B. Ketner EVOLUTION OF SEDIMENTARY BASINS EASTERN GREAT BASIN Harry E. Cook and Christopher J. Potter, Project Coordinators U.S. GEOLOGICAL SURVEY BULLETIN 1988-E A multidisciplinary approach to research studies of sedimentary rocks and their constituents and the evolution of sedimentary basins, both ancient and modern UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1993 U.S. DEPARTMENT OF THE INTERIOR BRUCE BABBITT, Secretary U.S. GEOLOGICAL SURVEY Robert M. Hirsch, Acting Director For sale by USGS Map Distribution Box 25286, Building 810 Denver Federal Center Denver, CO 80225 Any use of trade, product, or firm names in this publication is for descriptive purposes only and does not imply endorsement by the U.S. Government. Library of Congress Cataloging-in-Publication Data Sheehan, Peter M. Isolated carbonate bodies composed of stacked debris-flow deposits on a fine-grained carbonate lower slope of Devonian age, Antelope Peak, Elko County, Nevada / by Peter M. Sheehan, John M. Pandolfi, and Keith B. Ketner. p. cm. (U.S. Geological Survey bulletin ; 1988-E) (Evolution of sedimentary basins Eastern Great Basin ; ch. E) Includes bibliographical references. Supt.ofDocs.no.: I 19.3: 1988E 1. Rocks. Carbonate Nevada Elko County. 2. Geology, Stratigraphic Devonian. 3. Geology Nevada Elko County. I. Pandolfi, John M. II. Ketner, Keith Brindley, 1921- . III. Title. IV. Series. V. Series: Evolution of sedimentary basins Eastern Great Basin ; ch. E. QE75.B9 no. 1988-E [QE471.15.C3] 557.3 s dc20 93-3544 [552'.58'0979316] CIP CONTENTS Abstract................................................................................................................................. El Introduction........................................................................................................................... 1 Geologic Setting................................................................................................................... 2 Regional Geologic History................................................................................................... 3 The Carbonate Slope at Antelope Peak................................................................................ 4 Lower Part of the Roberts Mountains Formation....................................................... 4 Upper Part of the Roberts Mountains Formation....................................................... 5 Setting of the Roberts Mountains Formation.............................................................. 6 The Isolated Carbonate Bodies............................................................................................. 6 Origin of the Isolated Carbonate Bodies.............................................................................. 7 References Cited................................................................................................................... 9 FIGURES 1. Photographs showing carbonate body hosted in fine-grained, thin-bedded calcareous turbidites............................. E2 2. Map showing position of Silurian and Devonian carbonate-platform margin........................................................... 2 3. Sediment logs of slope deposits.................................................................................................................................. 4 4. Photographs showing calcareous slope turbidites....................................................................................................... 5 5. Sediment log of the largest carbonate body................................................................................................................ 7 6,7. Photographs showing: 6. Matrix-supported, disorganized conglomerates................................................................................................... 8 7. Large clasts from matrix-supported conglomerates ............................................................................................ 9 8. Schematic drawing showing reconstruction of the Devonian platform to basin transition........................................ 10 TABLE 1. Thickness of matrix-supported conglomerate beds and size of largest clasts in four intervals in the carbonate body described in figure 5.................................................................................................................................................... E7 Hi Isolated Carbonate Bodies Composed of Stacked Debris-Flow Deposits on a Fine-Grained Carbonate Lower Slope of Devonian Age, Antelope Peak, Elko County, Nevada By Peter M. Sheehan,1 John M. Pandolfi,2 and Keith B. Ketner3 ABSTRACT composed of stacks of numerous carbonate mud-supported sediment gravity-flow deposits. The Roberts Mountains Formation at Antelope Peak in Resedimented material deposited near carbonate shelf northeastern Nevada contains Lower Devonian isolated car­ margins is commonly derived from line sources (Schlager bonate bodies in a predominantly thin-bedded carbonate-tur- and Chermak, 1979). Line sources produce slope deposits bidi te sequence. The largest of five exposed bodies is 600 m in broad aprons arrayed parallel to the shelf margin (Cook wide and 47 m high. The turbidites that enclose the bodies and others, 1972, 1983; Cook and Mullins, 1983; Mullins, were deposited on an outer carbonate apron near the margin 1983; Mullins and others, 1984; Mullins and Cook, 1986). of a basin. The carbonate bodies are composed of as many as The aprons commonly are composed of grain flows, debris 150 discrete, matrix-supported conglomerate beds, each of flows, turbidites and periplatform ooze. In contrast, non- which was deposited by a separate debris-flow event. Clasts carbonate slopes are characterized by point sources; fans in the conglomerate beds are as much as 90 cm in diameter of sediment radiate from canyons that are fed clastic mate­ and were derived from the shallow carbonate shelf. Clasts rial by rivers and longshore currents (Mutti and Ricci Luc- include angular carbonate blocks, colonial corals, and large chi, 1978; Normark, 1978). Point-source deposits similar segments of fused pelmatozoan stems. The debris-flow
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