Middle Ordovician (Whiterockian) gastropods from central Sonora, Mexico: affinities with Laurentia and the Precordillera

Abstract The Lower–Middle Ordovician (Ibexian, Whiterockian) sedimentary rocks exposed at Rancho Las Norias includes the informally named Las Norias formation, which consists of an intercalation of carbonate and clastic sediments with abundant marine fauna. These deposits occur as the most austral s...

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Bibliographic Details
Published in:Journal of Paleontology
Main Authors: Cuen-Romero, Francisco Javier, Rohr, David M., Noriega-Ruiz, Héctor Arturo, Monreal, Rogelio, Blodgett, Robert B., Beresi, Matilde S., Buitrón-Sánchez, Blanca E.
Other Authors: Departamento de Geología - Universidad de Sonora
Format: Article in Journal/Newspaper
Language:English
Published: Cambridge University Press (CUP) 2022
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Online Access:http://dx.doi.org/10.1017/jpa.2022.25
https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0022336022000257
Description
Summary:Abstract The Lower–Middle Ordovician (Ibexian, Whiterockian) sedimentary rocks exposed at Rancho Las Norias includes the informally named Las Norias formation, which consists of an intercalation of carbonate and clastic sediments with abundant marine fauna. These deposits occur as the most austral sedimentary rocks of Ordovician age for Laurentia, providing a critical link to understand the distribution of Ordovician marine faunas of North America. An investigation of the gastropod fauna from the upper portion of the Las Norias formation, Sonora, Mexico, is undertaken for the first time. The gastropod assemblage includes Maclurites acuminatus , ? Monitorella sp., Lecanospira sp., Malayaspira aff. M . rugosa , Lophospira perangulata , and Hormotoma ? sp. This assemblage indicates a paleogeographic relationship with Laurentia, including the USA (Nevada), Canada (British Columbia, Newfoundland), Greenland, and the Argentine Precordillera.