Depositional systems of the late Eocene Yolomécatl Formation, northwestern Oaxaca, southeastern Mexico: a first approach

The discrimination/characterization of depositional systems recorded in formal lithostratigraphic, Cenozoic, continental, epiclastic units of Mexico, is largely a pending task, notwithstanding its great academic and economic importance. Contributing to fill this gap, we present a first approach to...

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Main Authors: Ismael Ferrusquía-Villafranca, José Ramón Torres-Hernández, José E. Ruiz-González, Enrique Martínez-Hernández
Format: Article
Language:English
Published: Universidad Nacional Autónoma de México 2018-07-01
Series:Revista Mexicana de Ciencias Geológicas
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Online Access:https://rmcg.unam.mx/index.php/rmcg/article/view/559
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author Ismael Ferrusquía-Villafranca
José Ramón Torres-Hernández
José E. Ruiz-González
Enrique Martínez-Hernández
author_facet Ismael Ferrusquía-Villafranca
José Ramón Torres-Hernández
José E. Ruiz-González
Enrique Martínez-Hernández
author_sort Ismael Ferrusquía-Villafranca
collection DOAJ
description The discrimination/characterization of depositional systems recorded in formal lithostratigraphic, Cenozoic, continental, epiclastic units of Mexico, is largely a pending task, notwithstanding its great academic and economic importance. Contributing to fill this gap, we present a first approach to discriminate and characterize the depositional systems of the late Eocene Yolomécatl Formation, which fills the namesake, triangle-shaped tectonic basin, and carries the southernmost Paleogene vertebrate fauna of North America. The study area lies between 17°25’–17°30’ North Latitude and 97°29’–97°36’ West Longitude, and between 2000–2500 m a.s.l.; the federal highway 125 traverses it; Santiago Yolomécatl is the main town. The Yolomécatl Formation is at least 650 m thick, although the continuous thickness measured in the principal reference section is much less (~250 m); it includes fluvial and lake depositional systems sparsely interbedded by tuff sheets (a system per se). The fluvial system consists of 1) Gmm, Gmg, Gcm lithofacies: alluvial fans and related deposits; 2) Gm, Gh, Gp, Gt, St, Sp lithofacies: channel lag deposits; 3) Sr, Sh, Sl, Fl lithofacies: floodplain deposits. The (clastic) lacustrine system includes: 1) Ll, Lsm, Lm lithofacies: offshore deposits; 2) Ll, Lsm lithofacies: playa lake and mud flats deposits. This large thickness of this unit indicates superposition of fluvial/lacustrine systems, and sparse pyroclastic emplacements that took place in a basin gradually subsiding with sedimentation, under humid to subhumid conditions, probably interrupted by seasonal dryness. Finally, the tectonic setting of the Yolomécatl Basin, indicates that its genesis and development are related to the dynamics of the regional, left-lateral strike-slip Tamazulapam fault, which is also regarded as the boundary between the Mixteca (west) and Oaxaca (east) terranes.
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spelling doaj-art-e94f574171b3434c9f1b8de33fa7c80a2025-08-20T03:20:29ZengUniversidad Nacional Autónoma de MéxicoRevista Mexicana de Ciencias Geológicas1026-87742007-29022018-07-0135210.22201/cgeo.20072902e.2018.2.559Depositional systems of the late Eocene Yolomécatl Formation, northwestern Oaxaca, southeastern Mexico: a first approachIsmael Ferrusquía-Villafranca0José Ramón Torres-Hernández1José E. Ruiz-González2Enrique Martínez-Hernández3Instituto de Geología, Universidad Nacional Autónoma de México, Circuito de la Investigación s/n, Ciudad Universitaria, Coyoacán, Ciudad de México, C.P. 04510, Mexico.Instituto de Geología, Universidad Autónoma de San Luis Potosí, Av. Dr. Manuel Nava 5, San Luis Potosí, C.P. 78000, Mexico.Instituto de Geología, Universidad Nacional Autónoma de México, Circuito de la Investigación s/n, Ciudad Universitaria, Coyoacán, Ciudad de México, C.P. 04510, Mexico.Instituto de Geología, Universidad Nacional Autónoma de México, Circuito de la Investigación s/n, Ciudad Universitaria, Coyoacán, Ciudad de México, C.P. 04510, Mexico. The discrimination/characterization of depositional systems recorded in formal lithostratigraphic, Cenozoic, continental, epiclastic units of Mexico, is largely a pending task, notwithstanding its great academic and economic importance. Contributing to fill this gap, we present a first approach to discriminate and characterize the depositional systems of the late Eocene Yolomécatl Formation, which fills the namesake, triangle-shaped tectonic basin, and carries the southernmost Paleogene vertebrate fauna of North America. The study area lies between 17°25’–17°30’ North Latitude and 97°29’–97°36’ West Longitude, and between 2000–2500 m a.s.l.; the federal highway 125 traverses it; Santiago Yolomécatl is the main town. The Yolomécatl Formation is at least 650 m thick, although the continuous thickness measured in the principal reference section is much less (~250 m); it includes fluvial and lake depositional systems sparsely interbedded by tuff sheets (a system per se). The fluvial system consists of 1) Gmm, Gmg, Gcm lithofacies: alluvial fans and related deposits; 2) Gm, Gh, Gp, Gt, St, Sp lithofacies: channel lag deposits; 3) Sr, Sh, Sl, Fl lithofacies: floodplain deposits. The (clastic) lacustrine system includes: 1) Ll, Lsm, Lm lithofacies: offshore deposits; 2) Ll, Lsm lithofacies: playa lake and mud flats deposits. This large thickness of this unit indicates superposition of fluvial/lacustrine systems, and sparse pyroclastic emplacements that took place in a basin gradually subsiding with sedimentation, under humid to subhumid conditions, probably interrupted by seasonal dryness. Finally, the tectonic setting of the Yolomécatl Basin, indicates that its genesis and development are related to the dynamics of the regional, left-lateral strike-slip Tamazulapam fault, which is also regarded as the boundary between the Mixteca (west) and Oaxaca (east) terranes. https://rmcg.unam.mx/index.php/rmcg/article/view/559MexicoOaxacaYolomécatl FormationEocenedepositional systems
spellingShingle Ismael Ferrusquía-Villafranca
José Ramón Torres-Hernández
José E. Ruiz-González
Enrique Martínez-Hernández
Depositional systems of the late Eocene Yolomécatl Formation, northwestern Oaxaca, southeastern Mexico: a first approach
Revista Mexicana de Ciencias Geológicas
Mexico
Oaxaca
Yolomécatl Formation
Eocene
depositional systems
title Depositional systems of the late Eocene Yolomécatl Formation, northwestern Oaxaca, southeastern Mexico: a first approach
title_full Depositional systems of the late Eocene Yolomécatl Formation, northwestern Oaxaca, southeastern Mexico: a first approach
title_fullStr Depositional systems of the late Eocene Yolomécatl Formation, northwestern Oaxaca, southeastern Mexico: a first approach
title_full_unstemmed Depositional systems of the late Eocene Yolomécatl Formation, northwestern Oaxaca, southeastern Mexico: a first approach
title_short Depositional systems of the late Eocene Yolomécatl Formation, northwestern Oaxaca, southeastern Mexico: a first approach
title_sort depositional systems of the late eocene yolomecatl formation northwestern oaxaca southeastern mexico a first approach
topic Mexico
Oaxaca
Yolomécatl Formation
Eocene
depositional systems
url https://rmcg.unam.mx/index.php/rmcg/article/view/559
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