Maastrichtian shallow-water ammonites of northeastern Mexico

In northeastern Mexico, extensive deltaic and prodeltaic sediment complexes developed during Maastrichtian times, known as the Difunta Group and Escondido Formation in Coahuila and the Northwest of Nuevo León, and the Cárdenas Formation in San Luis Potosí. These sediments contain abundant and diver...

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Main Authors: Christina Ifrim, Wolfgang Stinnesbeck, Armin Schafhauser
Format: Article
Language:English
Published: Universidad Nacional Autónoma de México 2018-05-01
Series:Revista Mexicana de Ciencias Geológicas
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Online Access:https://rmcg.unam.mx/index.php/rmcg/article/view/873
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author Christina Ifrim
Wolfgang Stinnesbeck
Armin Schafhauser
author_facet Christina Ifrim
Wolfgang Stinnesbeck
Armin Schafhauser
author_sort Christina Ifrim
collection DOAJ
description In northeastern Mexico, extensive deltaic and prodeltaic sediment complexes developed during Maastrichtian times, known as the Difunta Group and Escondido Formation in Coahuila and the Northwest of Nuevo León, and the Cárdenas Formation in San Luis Potosí. These sediments contain abundant and diverse invertebrate assemblages, among them the last ammonites in the area, prior to their extinction. Sphenodiscus (S. lobatus, S. pleurisepta) and Coahuilites sheltoni are the dominant elements of this paucispecific fauna and clearly favored shallow water coastal environments. Ammonites other than sphenodiscids are rare and restricted to occasional Baculites ovatus and a single Pachydiscus (Pachydiscus) neubergicus. This early (and possibly early late) Maastrichtian assemblage differs notably from the coeval ammonite fauna of the distal prodeltaic and open marine Méndez Formation in eastern Nuevo León. The latter assemblage is far more diverse (23 species referred to 18 genera) and includes, in addition to typical Gulf of Mexico faunal elements, many Tethyan, cosmopolitan, and even southern high latitude Indopacific species previously unknown from Mexico. Faunal differences between the two nearby outcrop areas are thus clearly related to paleobathymetry and not to paleobiogeography, being Baculites ovatus the only conspecific element.
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spelling doaj-art-e709754ece854bb0b4298aa1b741e5cc2025-08-20T03:20:30ZengUniversidad Nacional Autónoma de MéxicoRevista Mexicana de Ciencias Geológicas1026-87742007-29022018-05-01221Maastrichtian shallow-water ammonites of northeastern MexicoChristina Ifrim0Wolfgang Stinnesbeck1Armin Schafhauser2Institut für Regionale Geologie, Universität Karlsruhe, D-76131 Karlsruhe, Germany.Institut für Regionale Geologie, Universität Karlsruhe, D-76131 Karlsruhe, Germany.Institut für Regionale Geologie, Universität Karlsruhe, D-76131 Karlsruhe, Germany. In northeastern Mexico, extensive deltaic and prodeltaic sediment complexes developed during Maastrichtian times, known as the Difunta Group and Escondido Formation in Coahuila and the Northwest of Nuevo León, and the Cárdenas Formation in San Luis Potosí. These sediments contain abundant and diverse invertebrate assemblages, among them the last ammonites in the area, prior to their extinction. Sphenodiscus (S. lobatus, S. pleurisepta) and Coahuilites sheltoni are the dominant elements of this paucispecific fauna and clearly favored shallow water coastal environments. Ammonites other than sphenodiscids are rare and restricted to occasional Baculites ovatus and a single Pachydiscus (Pachydiscus) neubergicus. This early (and possibly early late) Maastrichtian assemblage differs notably from the coeval ammonite fauna of the distal prodeltaic and open marine Méndez Formation in eastern Nuevo León. The latter assemblage is far more diverse (23 species referred to 18 genera) and includes, in addition to typical Gulf of Mexico faunal elements, many Tethyan, cosmopolitan, and even southern high latitude Indopacific species previously unknown from Mexico. Faunal differences between the two nearby outcrop areas are thus clearly related to paleobathymetry and not to paleobiogeography, being Baculites ovatus the only conspecific element. https://rmcg.unam.mx/index.php/rmcg/article/view/873ammonites, paleobathymetry, Maastrichtian, Upper Cretaceous, Mexico.
spellingShingle Christina Ifrim
Wolfgang Stinnesbeck
Armin Schafhauser
Maastrichtian shallow-water ammonites of northeastern Mexico
Revista Mexicana de Ciencias Geológicas
ammonites, paleobathymetry, Maastrichtian, Upper Cretaceous, Mexico.
title Maastrichtian shallow-water ammonites of northeastern Mexico
title_full Maastrichtian shallow-water ammonites of northeastern Mexico
title_fullStr Maastrichtian shallow-water ammonites of northeastern Mexico
title_full_unstemmed Maastrichtian shallow-water ammonites of northeastern Mexico
title_short Maastrichtian shallow-water ammonites of northeastern Mexico
title_sort maastrichtian shallow water ammonites of northeastern mexico
topic ammonites, paleobathymetry, Maastrichtian, Upper Cretaceous, Mexico.
url https://rmcg.unam.mx/index.php/rmcg/article/view/873
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AT arminschafhauser maastrichtianshallowwaterammonitesofnortheasternmexico