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Stratigraphic Correlations Between the Eagle Valley Evaporite and Minturn Formation, Eagle Basin, Northwest Colorado

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Stratigraphic Correlations Between the Eagle Valley Evaporite and Minturn Formation, Eagle Basin, Northwest Colorado Stratigraphic Correlations Between the Eagle Valley Evaporite and Minturn Formation, Eagle Basin, Northwest Colorado U.S. GEOLOGICAL SURVEY BULLETIN 1787-GG AVAILABILITY OF BOOKS AND MAPS OF THE U.S. GEOLOGICAL SURVEY Instructions on ordering publications of the U.S. Geological Survey, along with 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 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 monthly, which is for sale in microfiche from the U.S. Geological Survey Books and Open-File Reports Sales, Box 25286, Denver, CO 80225. 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, Tech­ Books of the U.S. Geological Survey are available over the niques of Water-Resources Investigations, Circulars, publications counter at the following U.S. Geological Survey offices, all of of general interest (such as leaflets, pamphlets, booklets), single which are authorized agents of the Superintendent of Documents. copies of periodicals (Earthquakes & Volcanoes, Preliminary De­ termination of Epicenters), and some miscellaneous reports, includ­ ANCHORAGE, Alaska-4230 University Dr., Rm. 101 ing some of the foregoing series that have gone out of print at the Superintendent of Documents, are obtainable by mail from ANCHORAGE, Alaska-605 West 4th Ave., Rm G-84 DENVER, Colorado-Federal Bldg., Rm. 169,1961 Stout St. U.S. Geological Survey, Books and Open-File Report Sales Box 25286 LAKEWOOD, Colorado-Federal Center, Bldg. 810 Denver, CO 80225 MENLO PARK, California-Bldg. 3, Rm. 3128, 345 Middlefield Rd. 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Residents of Alaska may order maps from FAIRBANKS, Alaska-New Federal Building, 101 Twelfth U.S. Geological Survey, Map Sales Ave. 101 Twelfth Ave., Box 12 Fairbanks, AK 99701 Chapter GG Stratigraphic Correlations Between the Eagle Valley Evaporite and Minturn Formation, Eagle Basin, Northwest Colorado By CHRISTOPHER J. SCHENK A multidisciplinary approach to research studies of sedimentary rocks and their constituents and the evolution of sedimentary basins, both ancient and modern U.S. GEOLOGICAL SURVEY BULLETIN 1787 EVOLUTION OF SEDIMENTARY BASINS UINTA AND PICEANCE BASINS U.S. DEPARTMENT OF THE INTERIOR MANUEL LUJAN, JR., Secretary U.S. GEOLOGICAL SURVEY Dallas L. Peck, Director 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 UNITED STATES GOVERNMENT PRINTING OFFICE: 1992 For sale by Book and Open-File Report Sales U.S. Geological Survey Federal Center, Box 25286 Denver, CO 80225 Library of Congress Cataloging-in-Publication Data Schenk, Christopher J. Stratigraphic correlations between the Eagle Valley Evaporite and Minturn Formation, Eagle Basin, northwest Colorado / by Christopher J. Schenk. p. cm. (U.S. Geological Survey bulletin ; 1787) (Evolution of sedimentary basins Uinta and Piceance basins; ch. GG) Includes bibliographical references. Supt. of Docs. no. 119.3: 1787GG 1. Stratigraphic correlation Colorado. 2. Evaporites Colorado. 3. Geology, Stratigraphic Pennsylvanian. 4. Eagle Valley Formation (Colo.) 5. Minturn Formation (Colo.) I. Title. II. Series III. Series: Evolution of sedimentary basins Uinta and Piceance basins; ch. GG. QE75.B9 no. 1787-GG QE652.55 l.U] 557.3 s dc20 [551.7'52'09788] 2-15518 CIP CONTENTS Abstract GG1 Introduction GG1 Stratigraphy of the Minturn Formation and Eagle Valley Evaporite GG2 Correlations between the Eagle Valley Evaporite, Eagle Valley Formation, and the Minturn Formation GG4 Section X GG4 June Creek section GG4 Berry Creek section GG6 Squaw Creek section GG6 Section P GG6 Red Canyon section GG6 Discussion GG7 Summary GG7 References cited GG7 FIGURES 1. Map showing geology of study area and locations of measured sections, eastern Eagle basin, northwest Colorado GG2 2. Cross section from Eagle to Vail illustrating stratigraphic nomenclature discussed in this report GG3 3. Cross section showing correlations between measured sections in the study area GG5 Contents III EVOLUTION OF SEDIMENTARY BASINS UINTA AND PICEANCE BASINS Stratigraphic Correlations Between the Eagle Valley Evaporite and Minturn Formation, Eagle Basin, Northwest Colorado By Christopher J. Schenk Abstract INTRODUCTION Six Stratigraphic sections were used to correlate the Mid­ dle Pennsylvanian Eagle Valley Evaporite in the Eagle basin of northwest Colorado with the Minturn Formation. Correlations The purpose of this paper is to describe some strati- within the Eagle Valley sequence are complicated by the Wol- graphic correlations between the Middle Pennsylvanian cott syncline, which separates evaporites and clastic rocks of Eagle Valley Evaporite and Minturn Formation in the east­ the Eagle Valley Evaporite west of the syncline from predomi­ ern part of the Eagle basin, northwest Colorado (fig. 1). The nantly clastic units of the Eagle Valley Formation and Minturn eastern part of the Eagle basin, as used in this report, is the Formation east of the syncline. area north of the Sawatch uplift and west of the Gore Range. Correlations of units between measured sections on The Eagle Valley Evaporite is a sequence of mudstone, either side of the syncline indicate that many of the units of the sandstone, gypsum, halite, minor conglomerate, and carbon­ Minturn Formation (or Eagle Valley Formation) described from ate rocks deposited in the central part of the Eagle basin dur­ the area between Minturn and Avon, Colorado, are present in the Eagle Valley Evaporite on the west side of the syncline. The ing the Middle Pennsylvanian (Mallory, 1971). Coeval Jacque Mountain Limestone Member and the upper, middle, sediments of the Minturn Formation deposited along the and lower beds of the Robinson Limestone Member of the Min­ northeastern margin of the Eagle basin include sandstone, turn Formation previously have been identified as continuous mudstone, conglomerate, and carbonate rocks. Tweto and at least to the eastern edge of the syncline. In this study, the others (1978) differentiated the Eagle Valley Evaporite from Jacque Mountain and the Robinson were tentatively identified on the west side of the syncline in the Eagle Valley Evaporite the Eagle Valley Formation on the basis of the significantly and are considered to be members of the Eagle Valley Evapor­ lower evaporite content of the Eagle Valley Formation. ite. Three carbonate beds on the west side of the syncline may They considered the Eagle Valley Formation to be a transi­ be the upper, middle, and lower beds of the Robinson Lime­ tion between the Eagle Valley Evaporite and the Minturn stone Member. Several gypsum beds in the Eagle Valley Formation and mapped the Eagle Valley Formation in the Evaporite probably correlate with gypsum beds on the east side area east of the Wolcott syncline (fig. 1). My studies indi­ of the syncline, although heavy cover exists on the east side. Two prominent unnamed clastic units of the Minturn Forma­ cate, however, that the Eagle Valley Formation probably tion on the east side of the syncline probably correlate with represents a transition between the Eagle Valley Evaporite clastic units of the Eagle Valley Evaporite on the west side of and the Maroon Formation rather than the Mintum Forma­ the syncline. tion (fig. 2). The Eagle Valley Evaporite was generally These correlations indicate that the stratigraphy of the mapped west and south of the Wolcott syncline. Boggs Minturn Formation westward from the type section is similar to (1964,1966) and Tillman (1971), whose work preceded the the stratigraphy of the Eagle Valley Evaporite in the area of the published map of Tweto and others (1978), considered Wolcott syncline. Previous interpretations have suggested that the members of the Minturn Formation pinch out westward rocks in the Eagle Valley Formation east of the Wolcott syn­ into evaporitic rocks. cline to be part of the Minturn Formation. Correlations Between Eagle Valley Evaporite and Minturn Formation, Colorado GG1 106°45' 106°30' 39°45' - Type section of Eagle Valley Evaporite Type section of Minturn Formation Minturn . 39°30' - 10 KILOMETERS EXPLANATION
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