Chemical taphonomy and preservation modes of Jurassic spinicaudatans from Patagonia: A chemometric approach

Spinicaudatans ('clam shrimps') are small branchiopod crustaceans enclosed in a chitinous bivalved carapace that is often the only preserved element in the fossil record. However, few studies have analyzed the preservation of these carapaces, which have been found in continental facies fro...

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Publicado: 2018
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Acceso en línea:https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00223360_v92_n6_p1054_Monferran
http://hdl.handle.net/20.500.12110/paper_00223360_v92_n6_p1054_Monferran
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spelling paper:paper_00223360_v92_n6_p1054_Monferran2023-06-08T14:49:51Z Chemical taphonomy and preservation modes of Jurassic spinicaudatans from Patagonia: A chemometric approach bivalve chemical analysis crustacean Devonian diagenesis facies fossil record Jurassic ornamentation preservation recrystallization taphonomy Argentina Patagonia Branchiopoda Conchostraca Crustacea Spinicaudatans ('clam shrimps') are small branchiopod crustaceans enclosed in a chitinous bivalved carapace that is often the only preserved element in the fossil record. However, few studies have analyzed the preservation of these carapaces, which have been found in continental facies from the Devonian to the present. The aim of this study was to contribute to a better understanding of the chemical preservation of fossil spinicaudatan carapaces, and it focused on spinicaudatan carapaces of the Cañadón Asfalto Formation from the Jurassic of Argentina. Semiquantitative energy-dispersive X-ray spectrometry (EDS) analysis provided elemental composition data that were interpreted using principal component analysis (PCA). The results showed a complex chemical mode of preservation for spinicaudatan carapaces. In some parts, EDS spectra of the specimens exhibit peaks of calcium, phosphorous, aluminum, and fluorine, representing the retention of original carapace material with some diagenetic recrystallization. Certain zones of the carapace show low-intensity peaks of the elements mentioned, while silicon and oxygen peaks (from the rock matrix) become the dominant spectral signals. These modes of preservation modify the interpretations and observations of the ornamentation of the carapace, which are used as taxonomic features. Our results suggest that specific diagenetic processes play a fundamental role in the preservation of spinicaudatans. © 2018, The Paleontological Society. 2018 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00223360_v92_n6_p1054_Monferran http://hdl.handle.net/20.500.12110/paper_00223360_v92_n6_p1054_Monferran
institution Universidad de Buenos Aires
institution_str I-28
repository_str R-134
collection Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA)
topic bivalve
chemical analysis
crustacean
Devonian
diagenesis
facies
fossil record
Jurassic
ornamentation
preservation
recrystallization
taphonomy
Argentina
Patagonia
Branchiopoda
Conchostraca
Crustacea
spellingShingle bivalve
chemical analysis
crustacean
Devonian
diagenesis
facies
fossil record
Jurassic
ornamentation
preservation
recrystallization
taphonomy
Argentina
Patagonia
Branchiopoda
Conchostraca
Crustacea
Chemical taphonomy and preservation modes of Jurassic spinicaudatans from Patagonia: A chemometric approach
topic_facet bivalve
chemical analysis
crustacean
Devonian
diagenesis
facies
fossil record
Jurassic
ornamentation
preservation
recrystallization
taphonomy
Argentina
Patagonia
Branchiopoda
Conchostraca
Crustacea
description Spinicaudatans ('clam shrimps') are small branchiopod crustaceans enclosed in a chitinous bivalved carapace that is often the only preserved element in the fossil record. However, few studies have analyzed the preservation of these carapaces, which have been found in continental facies from the Devonian to the present. The aim of this study was to contribute to a better understanding of the chemical preservation of fossil spinicaudatan carapaces, and it focused on spinicaudatan carapaces of the Cañadón Asfalto Formation from the Jurassic of Argentina. Semiquantitative energy-dispersive X-ray spectrometry (EDS) analysis provided elemental composition data that were interpreted using principal component analysis (PCA). The results showed a complex chemical mode of preservation for spinicaudatan carapaces. In some parts, EDS spectra of the specimens exhibit peaks of calcium, phosphorous, aluminum, and fluorine, representing the retention of original carapace material with some diagenetic recrystallization. Certain zones of the carapace show low-intensity peaks of the elements mentioned, while silicon and oxygen peaks (from the rock matrix) become the dominant spectral signals. These modes of preservation modify the interpretations and observations of the ornamentation of the carapace, which are used as taxonomic features. Our results suggest that specific diagenetic processes play a fundamental role in the preservation of spinicaudatans. © 2018, The Paleontological Society.
title Chemical taphonomy and preservation modes of Jurassic spinicaudatans from Patagonia: A chemometric approach
title_short Chemical taphonomy and preservation modes of Jurassic spinicaudatans from Patagonia: A chemometric approach
title_full Chemical taphonomy and preservation modes of Jurassic spinicaudatans from Patagonia: A chemometric approach
title_fullStr Chemical taphonomy and preservation modes of Jurassic spinicaudatans from Patagonia: A chemometric approach
title_full_unstemmed Chemical taphonomy and preservation modes of Jurassic spinicaudatans from Patagonia: A chemometric approach
title_sort chemical taphonomy and preservation modes of jurassic spinicaudatans from patagonia: a chemometric approach
publishDate 2018
url https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00223360_v92_n6_p1054_Monferran
http://hdl.handle.net/20.500.12110/paper_00223360_v92_n6_p1054_Monferran
_version_ 1768544988882272256