HOLOCENE BIOCLASTIC ACCUMULATIONS FROM CABO FRIO COASTAL PLAIN, SOUTHEASTERN BRAZIL: TAXONOMIC COMPOSITION, TAPHONOMIC ASPECTS, GEOCHRONOLOGY AND PALEOENVIRONMENTAL IMPLICATIONS

Authors

  • Aline Meneguci Cunha Museu Nacional da Universidade Federal do Rio de Janeiro
  • João Wagner Alencar Castro Museu Nacional da Universidade Federal do Rio de Janeiro
  • Marcelo Araújo Carvalho Museu Nacional da Universidade Federal do Rio de Janeiro

Keywords:

Bioclastic accumulations, Mollusks, Holocene, Cabo Frio, Southeast Brazil.

Abstract

The bioclastic accumulations produced during the Holocene transgression are recorded in the entire coastal zone of South America, and allow the correlation of different areas. In order to place information from taxonomy, taphonomic process and paleoecology in this context, the analyses of mollusk fauna from six different sites located in the coastal plain of Cabo Frio area, southeastern Brazil, were integrated with sea level and paleoenvironmental changes. The taxonomic analysis identified 42 species of mollusks, being 25 of Bivalvia Class, 15 of Gastropoda Class and 2 of Scaphoda Class. The taphonomic analysis demonstrated two types of assemblages, an autocthonous, formed in anoxic and hypersaline conditions, and an allochthonous, characterized by shallow marine environment. Radiocarbon dating revealed the ages between 6260 and 5819 cal. yr BP. Cluster analysis revealed four fauna associations: Anomalocardia brasiliana, Tivela mactroides, Neritina virginea / Olivella and Pitar fulminatus. The integration of mollusk associations and taphonomic signatures allowed distinguished two paleoenvironments: a marine restricted (6200—5950 cal. yrs BP) dominated by Anomalocardia brasiliana Association with low degree of abrasion and fragmentation, evidence of low-energy environment; and 2) nearshore nearshore (5950—5800 cal. yrs BP) dominated by Tivela mactroides, Neritina virginea / Olivella and Pitar fulminatus Associations with a high degree of fragmentation and disarticulation, denoting a high wave energy environment and marine currents.

Author Biographies

Aline Meneguci Cunha, Museu Nacional da Universidade Federal do Rio de Janeiro

Departamento de Geologia e Paleontologia, Laboratório de Geologia Costeira, Sedimentologia e Meio Ambiente

João Wagner Alencar Castro, Museu Nacional da Universidade Federal do Rio de Janeiro

Departamento de Geologia e Paleontologia, Laboratório de Geologia Costeira, Sedimentologia e Meio Ambiente

Marcelo Araújo Carvalho, Museu Nacional da Universidade Federal do Rio de Janeiro

Departamento de Geologia e Paleontologia, Laboratório de Paleoecologia Vegetal

Published

2018-02-21

How to Cite

Cunha, A. M., Castro, J. W. A., & Carvalho, M. A. (2018). HOLOCENE BIOCLASTIC ACCUMULATIONS FROM CABO FRIO COASTAL PLAIN, SOUTHEASTERN BRAZIL: TAXONOMIC COMPOSITION, TAPHONOMIC ASPECTS, GEOCHRONOLOGY AND PALEOENVIRONMENTAL IMPLICATIONS. Ameghiniana, 55(1), 55 - 74. Retrieved from https://ameghiniana.org.ar/index.php/ameghiniana/article/view/2979

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Section

Articles