Revisions to Stratigraphic Nomenclature of Jurassic and Cretaceous Rocks of the Colorado Plateau
Total Page:16
File Type:pdf, Size:1020Kb
Revisions to Stratigraphic Nomenclature of Jurassic and Cretaceous Rocks of the Colorado Plateau U.S. GEOLOGICAL SURVEY BULLETIN 1633 A-C 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 cur rent-year issues of the monthly catalog "New Publications of the U.S. Geological Survey." Prices of available U.S. Geological Sur vey publications released prior to the current year are listed in the most recent annual "Price and Availability List." Publications that are listed in various U.S. Geological Survey catalogs (see back inside cover) but not listed in the most recent annual "Price and Availability List" are no longer available. Prices of reports released to the open files are given in the listing "U.S. Geological Survey Open-File Reports," updated month ly, which is for sale in microfiche from the U.S. Geological Survey, Books and Open-File Reports Section, Federal Center, Box 25425, Denver, CO 80225. Reports released through the NTIS may be obtained by writing to the National Technical Information Service, U.S. Department of Commerce, Springfield, VA 22161; please include NTIS report number with inquiry. Order U.S. Geological Survey publications by mail or over the counter from the offices given below. BY MAIL _ . OVER THE COUNTER Books Books Professional Papers, Bulletins, Water-Supply Papers, Techniques of Water-Resources Investigations, Circulars, publications of general in- Books of the U.S. Geological Survey are available over the terest (such as leaflets, pamphlets, booklets), single copies of Earthquakes counter at the following Geological Survey Public Inquiries Offices, all & Volcanoes, Preliminary Determination of Epicenters, and some mis- of which are authorized agents of the Superintendent of Documents: cellaneous reports, including some of the foregoing series that have gone out of print at the Superintendent of Documents, are obtainable by mail from WASHINGTON, D.C.-Main Interior Bldg., 2600 corridor, 18thandCSts.,NW. U.S. Geological Survey, Books and Open-File Reports DENVER, Colorado-Federal Bldg., Rm. 169, 1961 Stout St. Federal Center, Box 25425 LOS ANGELES, California-Federal Eldg., Rm. 7638, 300 N. Denver, CO 80225 Los Angeles St. MENLO PARK, California-Bldg. 3 (Stop 533), Rm. 3128, Subscriptions to periodicals (Earthquakes & Volcanoes and 345 Middlefield Rd. Preliminary Determination of Epicenters) can be obtained ONLY from RESTON, Virginia-503 National Center, Rm. 1C402,12201 the Sunrise Valley Dr. SALT LAKE CITY, Utah-Federal Bldg., Rm. 8105,125 Superintendent of Documents South State St. Government Printing Office SAN FRANCISCO, California-Customhouse, Rm. 504,555 Washington, D.C. 20402 Battery St. SPOKANE, Washington-US. Courthouse, Rm. 678, West (Check or money order must be payable to Superintendent of Docu- 920 Riverside Ave.. ments.) ANCHORAGE, Alaska-Rm. 101, 4230 University Dr. ANCHORAGE, Alaska-Federal Bldg, Rm. E-146, 701 C St. Maps For maps, address mail orders to U.S. Geological Survey, Map Distribution Maps Federal Center, Box 25286 Maps may ^ purchased over ^ counter at the U.S. Geologi- Denver, CO 80225 caj Sm^y Offices where books are sold (all addresses in above list) and at the following Geological Survey offices: Residents of Alaska may order maps from ROLLA, Missouri-1400 Independence Rd. Alaska Distribution Section, U.S. Geological Survey, . DENVER, Colorado-Map Distribution, Bldg. 810, Federal New Federal Building - Box 12 Center 101 Twelfth Ave., Fairbanks, AK 99701 . FAIRBANKS, Alaska-New Federal Bldg., 101 Twelfth Ave. Revisions to Stratigraphic Nomenclature of Jurassic and Cretaceous Rocks of the Colorado Plateau Revisions in Nomenclature of the Middle Jurassic Wanakah Formation, Northwestern New Mexico and Northeastern Arizona By STEVEN M. CONDON and A. CURTIS HUFFMAN, JR. Stratigraphy and Nomenclature of Middle and Upper Jurassic Rocks, Western Colorado Plateau, Utah and Arizona By FRED PETERSON The Encinal Canyon Member, a New Member of the Upper Cretaceous Dakota Sandstone in the Southern and Eastern San Juan Basin, New Mexico By WILLIAM M. AUBREY U.S. GEOLOGICAL SURVEY BULLETIN 1633 A-C DEPARTMENT OF THE INTERIOR DONALD PAUL MODEL, Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director UNITED STATES GOVERNMENT PRINTING OFFICE: 1988 For sale by the Books and Open-File Reports Section U.S. Geological Survey Federal Center, Box 25425 Denver, CO 80225 Any use of trade names is for descriptive purposes only and does not imply endorsement by the U.S. Geological Survey. Library of Congress Cataloging-in-Publication Data Revisions to stratigraphic nomenclature of Jurassic and Cretaceous rocks of the Colorado Plateau. (U.S. Geological Survey bulletin ; 1633 A-C) Includes bibliographies. Supt. of Docs, no.: I 19.3:1633A-C Contents: Revisions in nomenclature of the Middle Jurassic Wanakah Formation, northwestern New Mexico and northeastern Arizona / by Steven M. Condon and A. Curtis Huffman Stratigraphy and nomenclature of Middle and Upper Jurassic rocks, western Colorado Plateau, Utah and Arizona / by Fred Peterson The Encinal Canyon Member, a new member of the Upper Cretaceous Dakota Sandstone in the southern and eastern San Juan Basin, New Mexico / by William M. Aubrey. 1. Geology, Stratigraphic Jurassic Nomenclature. 2. Geology, Stratigraphic Cretaceous Nomenclature. 3. Geology, Stratigraphic Nomenclature Colorado Plateau. I. Condon, Steven M. II. Series. QE75.B9 no. 1633 A-C 557.3 s 87-600053 [QE681] [551.7'66'014] CONTENTS [Letters indicate the chapters] (A) Revisions in nomenclature of the Middle Jurassic Wanakah Formation, northwestern New Mexico and northeastern Arizona, by Steven M. Condon and A. Curtis Huffman, Jr. 1 (B) Stratigraphy and nomenclature of Middle and Upper Jurassic rocks, western Colorado Plateau, Utah and Arizona, by Fred Peterson 13 (C) The Encinal Canyon Member, a new member of the Upper Cretaceous Dakota Sandstone in the southern and eastern San Juan Basin, New Mexico, by William M. Aubrey 57 Contents III Chapter A Revisions in Nomenclature of the Middle Jurassic Wanakah Formation, Northwestern New Mexico and Northeastern Arizona By STEVEN M. CONDON and A. CURTIS HUFFMAN, JR. "Wanakah Formation" replaces "Summerville Formation" in New Mexico and Arizona U.S. GEOLOGICAL SURVEY BULLETIN 1633-A REVISIONS TO STRATIGRAPHIC NOMENCLATURE OF JURASSIC AND CRETACEOUS ROCKS OF THE COLORADO PLATEAU CONTENTS Abstract 3 Introduction 3 Stratigraphy and depositional environments Upper and lower contacts 7 Reference section 10 References cited 10 FIGURES Al. Location map of northwestern New Mexico, northeastern Arizona, and ad jacent areas 4 A2. Chart showing nomenclature applied by various authors to Jurassic rocks in the Four Corners region 5 A3. Cross section of the Wanakah Formation from Toh Atin Mesa, Ariz., to Navajo, N. Mex. 6 A4. Photographs of Wanakah Formation and adjacent formations at measured section localities 8 A5. Map showing Todilto-Pony Express basin of deposition and the approx imate distribution of the gypsum-anhydrite unit 10 A6. General paleogeography of the Four Corners region in Todilto-early Beclabito-early Cow Springs time 10 A7. Reference section of the Wanakah Formation and its Todilto Limestone Member and type section of its Beclabito and Horse Mesa Members 11 Contents REVISIONS TO STRATIGRAPHIC NOMENCLATURE OF JURASSIC AND CRETACEOUS ROCKS OF THE COLORADO PLATEAU Revisions in Nomenclature of the Middle Jurassic Wanakah Formation, Northwestern New Mexico and Northeastern Arizona By Steven M. Condon and A. Curtis Huffman, Jr. Abstract (1941) also considered the Wanakah to be a member of the Morrison; however, they restricted the name to sandy, Use of the name Summerville Formation in northwestern red, argillaceous strata that are now called the upper or New Mexico and northeastern Arizona is here discontinued, marl member of the Wanakah. They named an underly and this name is replaced by the name Wanakah Formation ing red sandstone the Bilk Creek Sandstone Member of in that area. In New Mexico and Arizona the Wanakah con the Morrison, and assigned Burbank's "Pony Express sists of the basal Todilto Limestone Member and two new beds" to the base of the Morrison as the Pony Express members, the Beclabito and Horse Mesa Members. The Limestone Member. Eckel (1949, p. 28) elevated the Wanakah overlies the Entrada Sandstone, underlies the Mor- rison Formation, and intertongues laterally with the Cow Springs Wanakah to formation rank and extended the name to Sandstone. On the basis of previously established stratigraphic the La Plata Mountains area (fig. Al), where it consists relations, the Wanakah is considered to be Middle Jurassic in of the Pony Express Limestone Member at the base, the age. Bilk Creek Sandstone Member, and the marl member. In this report, our use of the name Wanakah Formation in northwestern New Mexico and northeastern Arizona INTRODUCTION follows that of Baker and others (1947, p. 1668) and Imlay (1952, p. 960), who included the Todilto Lime The Middle Jurassic Wanakah Formation of the stone, an equivalent of the Pony Express, as the basal San Rafael Group is here reinstated throughout north member of the Wanakah Formation (fig. A2). western New Mexico and northeastern Arizona and In this report we are establishing a reference sec replaces the name Summerville Formation in those areas. tion for the Todilto Limestone Member and the Wanakah This change in stratigraphic nomenclature is necessary Formation, and a type section for the Beclabito (bek-'la- because recent stratigraphic reports (O'Sullivan, 1980a, bito) and Horse Mesa Members at Horse Mesa, Arizona 1981; O'Sullivan and Pierce, 1983) have documented the and New Mexico, in sec. 17, T. 38 N., R. 31 E. (Gila/Salt reasons for limiting use of the name Summerville For River grid) and sees. 26 and 27, T. 29 N., R. 21 W. (New mation to the San Rafael Swell-Monument upwarp area Mexico grid). At Horse Mesa the Wanakah consists of of Utah (fig. Al). These reports have applied the name the Todilto Limestone Member at the base, the Beclabito Wanakah Formation to red beds in southeastern Utah Member, and the Horse Mesa Member.