Taphonomy of Bouchardia rosea (Rhynchonelliformea, Brachiopoda) shells from Ubatuba Bay, Brazil: implications for the use of taphonomic signatures in (paleo)environmental analysis

Autor(es)

Coelho Rodrigues, Sabrina ^[1] ; Guimaraes Simoes, Marcello ^[2]

Afiliação do(s) autor(es)

^[1] Univ Fed Uberlandia, Fac Ciencias Integradas Pontal, BR-38302000 Ituiutaba, MG - Brazil

^[2] Univ Estadual Paulista, Inst Biociencias, BR-18610000 Botucatu, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: AMEGHINIANA; v. 47, n. 3, p. 373-386, SEP 30 2010.
• Citações Web of Science: 9

Resumo

This study analyzes taphonomic alteration of brachiopod shells, i.e., Bouchardia rosea (Mawe) from Ubatuba Bay, northern coast of Sao Paulo State, Brazil. The average age of the studied shell deposits is 674 years BP. The underlying hypothesis is that taphonomic signatures are not uniformly distributed along a bathymetric gradient. Assemblages were sampled using a Van Veen grab sampler (31 x 40cm) along transect of fourteen stations from zero (beach) to 35 m water depth. Four sedimentary environments were recognized: (a) beach, (b) protected bay with clay bottom, (c) protected bay with sandy bottom, and (d) inner shelf with sandy bottom. All brachiopod shells (i.e., total fraction including fragments) from each of the five stations with appreciable accumulations (up to 1607 shells) were investigated following a protocol of ten taphonomic signatures. Six of these ten taphonomic signatures (articulation, fragmentation, edge alteration, color alteration, bioerosion, and encrustation) were homogeneously distributed among studied environments, indicating that these general types of taphonomic signatures per se are not sensitive to environmental conditions in this case. On the other hand, shell surface texture varied along the bathymetric gradient, thus showing a high potential to be used in taphofacies analyses. Several examples of taphonomic generalizations available in the literature are neither applicable nor comparable to our results, which further confirm that overgeneralizations should be avoided in taphonomic studies. (AU)

• Processo FAPESP: 06/59416-8 - Iniciativas geológicas/paleontológicas para implantação da linha de pesquisa em Paleobiologia da conservação: o caso de Bouchardia rosea (Brachiopoda, Rhynchonelliformea) na plataforma Sudeste do Brasil
• Beneficiário: Sabrina Coelho Rodrigues
• Modalidade de apoio: Bolsas no Brasil - Pós-Doutorado
• Processo FAPESP: 02/13552-7 - Gradientes tafonômicos em tanatocenoses de moluscos bivalves em baías e na plataforma interna no Norte do estado de São Paulo: implicações no uso de dados tafonômicos para o reconhecimento de tatofácies
• Beneficiário: Sabrina Coelho Rodrigues
• Modalidade de apoio: Bolsas no Brasil - Doutorado
• Processo FAPESP: 06/00169-1 - Sistemática e tafonomia dos braquiópodes (Rhynchonelliformea) recentes, da plataforma continental brasileira (estados de São Paulo e Rio Grande do Sul) e do Paleógeno da Argentina: implicações paleoecológicas e paleobiogeográficas
• Beneficiário: Marcello Guimarães Simões
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 00/12659-7 - Brachiopod and Bivalve taphonomy in subtropical siliciclastic settings of northern coast of São Paulo State: enviromental variation in taphonomic signatures, biostratinomic style and time-averaging
• Beneficiário: Marcello Guimarães Simões
• Modalidade de apoio: Auxílio à Pesquisa - Regular