Barremian bivalves from the Huitrín formation, west-central Argentina: Taxonomy and paleoecology of a restricted marine association

The Cretaceous Huitrín Formation in west-central Argentina records the final connection of the Neuquén Basin to the Pacific Ocean. This formation is comprised of a variety of continental to marginal-marine sediments deposited behind an Andean volcanic arc under warm, arid paleoclimatic conditions. H...

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Autores principales: Lazo, D.G., Damborenea, S.E.
Formato: JOUR
Materias:
Barremian Bivalves
Huitrín Formation
Paleoecology
Taxonomy
West-Central Argentina
bivalve
brackish water
continental margin
Cretaceous
endemic species
evaporation
fossil record
freshwater environment
hypersaline environment
limiting factor
marine ecosystem
marine sediment
observational method
paleoclimate
paleoecology
paleoenvironment
population distribution
primary production
rainfall
runoff
salinity
species diversity
species evenness
taxonomy
temperature effect
Argentina
Pacific Ocean
Bivalvia
Isognomon
Nanus
Acceso en línea:http://hdl.handle.net/20.500.12110/paper_00223360_v85_n4_p719_Lazo
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Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) de Universidad de Buenos Aires
id todo:paper_00223360_v85_n4_p719_Lazo
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spelling todo:paper_00223360_v85_n4_p719_Lazo2023-10-03T14:31:42Z Barremian bivalves from the Huitrín formation, west-central Argentina: Taxonomy and paleoecology of a restricted marine association Lazo, D.G. Damborenea, S.E. Barremian Bivalves Huitrín Formation Paleoecology Taxonomy West-Central Argentina bivalve brackish water continental margin Cretaceous endemic species evaporation fossil record freshwater environment hypersaline environment limiting factor marine ecosystem marine sediment observational method paleoclimate paleoecology paleoenvironment population distribution primary production rainfall runoff salinity species diversity species evenness taxonomy temperature effect Argentina Pacific Ocean Bivalvia Isognomon Nanus The Cretaceous Huitrín Formation in west-central Argentina records the final connection of the Neuquén Basin to the Pacific Ocean. This formation is comprised of a variety of continental to marginal-marine sediments deposited behind an Andean volcanic arc under warm, arid paleoclimatic conditions. Here we focus on a bivalve fauna from carbonate ramp deposits within the Barremian La Tosca Member of the Huitrín Formation. This fauna is very abundant and widely distributed within the basin but, surprisingly, it has not yet been studied in detail. In addition, paleoenvironmental affinities remain unresolved, with the fauna variously interpreted as having freshwater, brackish, and marine affinities. We studied the fauna's taxonomy and paleoecology based on more than 500 specimens collected at ten fossil localities in combination with new field observations. The bivalve assemblage was recorded from middle to outer carbonate ramp deposits and is composed of five taxa of marine affinity: Phelopteria huitriniana n. sp., Isognomon cf. I. nanus (Behrendsen), Placunopsis? pichi n. sp., Anthonya jarai n. sp., and Argenticyprina mulensis n. gen. n. sp.; the first three may be regarded as eurytopic and/or opportunistic. Reduced diversity, low evenness, overall small size (length <4 cm), thin shells, eurytopic or opportunistic life strategies, and high endemism point to a restricted marine setting for the La Tosca Member. The most important limiting factors likely were low primary productivity and fluctuating salinity and temperature, as conditions inferred for the unit include high evaporation rates combined with low continental runoff and reduced rainfall. Thick evaporite deposits below and above La Tosca Member and thin intercalated gypsum beds support a restricted, hypersaline setting. © 2011 The Paleontological Society. JOUR info:eu-repo/semantics/openAccess http://creativecommons.org/licenses/by/2.5/ar http://hdl.handle.net/20.500.12110/paper_00223360_v85_n4_p719_Lazo
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic Barremian Bivalves
Huitrín Formation
Paleoecology
Taxonomy
West-Central Argentina
bivalve
brackish water
continental margin
Cretaceous
endemic species
evaporation
fossil record
freshwater environment
hypersaline environment
limiting factor
marine ecosystem
marine sediment
observational method
paleoclimate
paleoecology
paleoenvironment
population distribution
primary production
rainfall
runoff
salinity
species diversity
species evenness
taxonomy
temperature effect
Argentina
Pacific Ocean
Bivalvia
Isognomon
Nanus
spellingShingle Barremian Bivalves
Huitrín Formation
Paleoecology
Taxonomy
West-Central Argentina
bivalve
brackish water
continental margin
Cretaceous
endemic species
evaporation
fossil record
freshwater environment
hypersaline environment
limiting factor
marine ecosystem
marine sediment
observational method
paleoclimate
paleoecology
paleoenvironment
population distribution
primary production
rainfall
runoff
salinity
species diversity
species evenness
taxonomy
temperature effect
Argentina
Pacific Ocean
Bivalvia
Isognomon
Nanus
Lazo, D.G.
Damborenea, S.E.
Barremian bivalves from the Huitrín formation, west-central Argentina: Taxonomy and paleoecology of a restricted marine association
topic_facet Barremian Bivalves
Huitrín Formation
Paleoecology
Taxonomy
West-Central Argentina
bivalve
brackish water
continental margin
Cretaceous
endemic species
evaporation
fossil record
freshwater environment
hypersaline environment
limiting factor
marine ecosystem
marine sediment
observational method
paleoclimate
paleoecology
paleoenvironment
population distribution
primary production
rainfall
runoff
salinity
species diversity
species evenness
taxonomy
temperature effect
Argentina
Pacific Ocean
Bivalvia
Isognomon
Nanus
description The Cretaceous Huitrín Formation in west-central Argentina records the final connection of the Neuquén Basin to the Pacific Ocean. This formation is comprised of a variety of continental to marginal-marine sediments deposited behind an Andean volcanic arc under warm, arid paleoclimatic conditions. Here we focus on a bivalve fauna from carbonate ramp deposits within the Barremian La Tosca Member of the Huitrín Formation. This fauna is very abundant and widely distributed within the basin but, surprisingly, it has not yet been studied in detail. In addition, paleoenvironmental affinities remain unresolved, with the fauna variously interpreted as having freshwater, brackish, and marine affinities. We studied the fauna's taxonomy and paleoecology based on more than 500 specimens collected at ten fossil localities in combination with new field observations. The bivalve assemblage was recorded from middle to outer carbonate ramp deposits and is composed of five taxa of marine affinity: Phelopteria huitriniana n. sp., Isognomon cf. I. nanus (Behrendsen), Placunopsis? pichi n. sp., Anthonya jarai n. sp., and Argenticyprina mulensis n. gen. n. sp.; the first three may be regarded as eurytopic and/or opportunistic. Reduced diversity, low evenness, overall small size (length <4 cm), thin shells, eurytopic or opportunistic life strategies, and high endemism point to a restricted marine setting for the La Tosca Member. The most important limiting factors likely were low primary productivity and fluctuating salinity and temperature, as conditions inferred for the unit include high evaporation rates combined with low continental runoff and reduced rainfall. Thick evaporite deposits below and above La Tosca Member and thin intercalated gypsum beds support a restricted, hypersaline setting. © 2011 The Paleontological Society.
format JOUR
author Lazo, D.G.
Damborenea, S.E.
author_facet Lazo, D.G.
Damborenea, S.E.
author_sort Lazo, D.G.
title Barremian bivalves from the Huitrín formation, west-central Argentina: Taxonomy and paleoecology of a restricted marine association
title_short Barremian bivalves from the Huitrín formation, west-central Argentina: Taxonomy and paleoecology of a restricted marine association
title_full Barremian bivalves from the Huitrín formation, west-central Argentina: Taxonomy and paleoecology of a restricted marine association
title_fullStr Barremian bivalves from the Huitrín formation, west-central Argentina: Taxonomy and paleoecology of a restricted marine association
title_full_unstemmed Barremian bivalves from the Huitrín formation, west-central Argentina: Taxonomy and paleoecology of a restricted marine association
title_sort barremian bivalves from the huitrín formation, west-central argentina: taxonomy and paleoecology of a restricted marine association
url http://hdl.handle.net/20.500.12110/paper_00223360_v85_n4_p719_Lazo
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