Taphonomic analysis of an autochthonous fossil concentration in Jurassic lacustrine deposits of Patagonia, Argentina
A new fossiliferous level from the Las Chacritas Member (Bajocian-Callovian) of the Cañadón Asfalto Formation, which crops out in the Cañadón Asfalto Basin (Extraandean-Chubut) Argentina was analyzed. The study of this assemblage was made on the basis of paleoecological, sedimentological and taphono...
| Publicado: |
2019
|
|---|---|
| Materias: | |
| Acceso en línea: | https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00310182_v514_n_p265_Zacarias http://hdl.handle.net/20.500.12110/paper_00310182_v514_n_p265_Zacarias |
| Aporte de: |
| id |
paper:paper_00310182_v514_n_p265_Zacarias |
|---|---|
| record_format |
dspace |
| spelling |
paper:paper_00310182_v514_n_p265_Zacarias2023-06-08T14:56:46Z Taphonomic analysis of an autochthonous fossil concentration in Jurassic lacustrine deposits of Patagonia, Argentina Argentina Cañadón Asfalto Formation Fossil concentration Marginal lacustrine facies Middle Jurassic Taphonomy autochthony bivalve diagenesis facies fossil assemblage fossil record gastropod Jurassic lacustrine deposit ostracod paleoecology seasonal variation silicification skeletal remains taphonomy Argentina Patagonia Bivalvia Brachyphyllum Characeae Coniferophyta Gastropoda Ostracoda A new fossiliferous level from the Las Chacritas Member (Bajocian-Callovian) of the Cañadón Asfalto Formation, which crops out in the Cañadón Asfalto Basin (Extraandean-Chubut) Argentina was analyzed. The study of this assemblage was made on the basis of paleoecological, sedimentological and taphonomic criteria. This polytypic assemblage is composed mainly of bivalves, spinicaudatans, gastropods, and ostracods, associated with plant remains (such as Brachyphyllum sp., Charophytes, conifers, seeds, and indeterminate remains). The tabular bed of oncolitic packstone facies corresponds to a shallow marginal lacustrine environment of intense organic productivity. Taphonomic and paleoecological features, such as closed articulated valves, random orientation, and size-frequency histograms indicate that the fauna is autochthonous. The short life cycle with a quick turnover of the population, suggests that the time averaging would only comprise a few years. In addition, the analysis of Energy dispersive X-ray spectrometry supports early diagenesis affecting the remains and favoring the dissolution of aragonite/calcite, as well as the silicification of shells. Therefore, this fossil assemblage can be classified as a sedimentological concentration, which could have been originated by seasonal cyclicity in an environment subject to water level fluctuations. © 2018 Elsevier B.V. 2019 https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00310182_v514_n_p265_Zacarias http://hdl.handle.net/20.500.12110/paper_00310182_v514_n_p265_Zacarias |
| institution |
Universidad de Buenos Aires |
| institution_str |
I-28 |
| repository_str |
R-134 |
| collection |
Biblioteca Digital - Facultad de Ciencias Exactas y Naturales (UBA) |
| topic |
Argentina Cañadón Asfalto Formation Fossil concentration Marginal lacustrine facies Middle Jurassic Taphonomy autochthony bivalve diagenesis facies fossil assemblage fossil record gastropod Jurassic lacustrine deposit ostracod paleoecology seasonal variation silicification skeletal remains taphonomy Argentina Patagonia Bivalvia Brachyphyllum Characeae Coniferophyta Gastropoda Ostracoda |
| spellingShingle |
Argentina Cañadón Asfalto Formation Fossil concentration Marginal lacustrine facies Middle Jurassic Taphonomy autochthony bivalve diagenesis facies fossil assemblage fossil record gastropod Jurassic lacustrine deposit ostracod paleoecology seasonal variation silicification skeletal remains taphonomy Argentina Patagonia Bivalvia Brachyphyllum Characeae Coniferophyta Gastropoda Ostracoda Taphonomic analysis of an autochthonous fossil concentration in Jurassic lacustrine deposits of Patagonia, Argentina |
| topic_facet |
Argentina Cañadón Asfalto Formation Fossil concentration Marginal lacustrine facies Middle Jurassic Taphonomy autochthony bivalve diagenesis facies fossil assemblage fossil record gastropod Jurassic lacustrine deposit ostracod paleoecology seasonal variation silicification skeletal remains taphonomy Argentina Patagonia Bivalvia Brachyphyllum Characeae Coniferophyta Gastropoda Ostracoda |
| description |
A new fossiliferous level from the Las Chacritas Member (Bajocian-Callovian) of the Cañadón Asfalto Formation, which crops out in the Cañadón Asfalto Basin (Extraandean-Chubut) Argentina was analyzed. The study of this assemblage was made on the basis of paleoecological, sedimentological and taphonomic criteria. This polytypic assemblage is composed mainly of bivalves, spinicaudatans, gastropods, and ostracods, associated with plant remains (such as Brachyphyllum sp., Charophytes, conifers, seeds, and indeterminate remains). The tabular bed of oncolitic packstone facies corresponds to a shallow marginal lacustrine environment of intense organic productivity. Taphonomic and paleoecological features, such as closed articulated valves, random orientation, and size-frequency histograms indicate that the fauna is autochthonous. The short life cycle with a quick turnover of the population, suggests that the time averaging would only comprise a few years. In addition, the analysis of Energy dispersive X-ray spectrometry supports early diagenesis affecting the remains and favoring the dissolution of aragonite/calcite, as well as the silicification of shells. Therefore, this fossil assemblage can be classified as a sedimentological concentration, which could have been originated by seasonal cyclicity in an environment subject to water level fluctuations. © 2018 Elsevier B.V. |
| title |
Taphonomic analysis of an autochthonous fossil concentration in Jurassic lacustrine deposits of Patagonia, Argentina |
| title_short |
Taphonomic analysis of an autochthonous fossil concentration in Jurassic lacustrine deposits of Patagonia, Argentina |
| title_full |
Taphonomic analysis of an autochthonous fossil concentration in Jurassic lacustrine deposits of Patagonia, Argentina |
| title_fullStr |
Taphonomic analysis of an autochthonous fossil concentration in Jurassic lacustrine deposits of Patagonia, Argentina |
| title_full_unstemmed |
Taphonomic analysis of an autochthonous fossil concentration in Jurassic lacustrine deposits of Patagonia, Argentina |
| title_sort |
taphonomic analysis of an autochthonous fossil concentration in jurassic lacustrine deposits of patagonia, argentina |
| publishDate |
2019 |
| url |
https://bibliotecadigital.exactas.uba.ar/collection/paper/document/paper_00310182_v514_n_p265_Zacarias http://hdl.handle.net/20.500.12110/paper_00310182_v514_n_p265_Zacarias |
| _version_ |
1768543123517997056 |