Jurassic Stratigraphy in West-Central New Mexico

ASU Author/Contributor (non-ASU co-authors, if there are any, appear on document)
Andrew B. Heckert Ph.D., Professor (Creator)
Appalachian State University (ASU )
Web Site: https://library.appstate.edu/

Abstract: Jurassic strata in west-central New Mexico encompass part of the southern edge of the Jurassic outcrop belt in the Western Interior. Some of the Jurassic units pinch out or are truncated southward in west-central New Mexico, so that in the southernmost reaches of the Jurassic outcrop belt the entire Jurassic section is merged eolian sandstones. Therefore, a dual lithostratigraphic nomenclature needs to be used for Jurassic strata in west-central New Mexico, one that refl ects the two different lithofacies belts. For convenience, we refer to these as the water-deposited and the eolian lithofacies belts. The Jurassic section in the water-deposited lithofacies belt is (in ascending order) the Entrada Sandstone (Dewey Bridge and Slick Rock members), Todilto Formation (Luciano Mesa and Tonque Arroyo members), Summerville Formation, Bluff Sandstone (main body and Recapture Member), Acoma Tongue of the Zuni Sandstone and Morrison Formation (Salt Wash, Brushy Basin and Jackpile members). In the eolian lithofacies belt, the entire Jurassic section is assigned to the Zuni Sandstone. The “Iyanbito Member” of the Entrada Sandstone is Triassic strata of the Wingate Sandstone and thus is removed from the Entrada, and the name Iyanbito Member is abandoned. The lithostratigraphy we advocate for Jurassic strata in west-central New Mexico is parsimonious; it refl ects regional lithostratigraphic geometry, embodies sound application of stratigraphic principles and is both practical and useful to geologists. It provides a sound basis for a Jurassic sequence stratigraphy in west-central New Mexico that recognizes four regional unconformities: J-2 (base of Entrada and Zuni sandstones), J-3 (base of Todilto Formation), J-5 (base of Salt Wash Member of Morrison Formation) and K-0 (base of Cretaceous Dakota Sandstone).

Additional Information

Lucas, S.G., and Heckert, A.B. (2003), Jurassic stratigraphy in west-central New Mexico: New Mexico Geological Society Guidebook 54, p. 289-301. Archived in NCDOCKS with permission of the editor. Version of record available at: http://nmgs.nmt.edu/publications/guidebooks/54/
Language: English
Date: 2003

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