Neoproterozoic glacial dynamics revealed by provenance of diamictites of the Bebedouro Formation, Sao Francisco Craton, Central Eastern Brazil

Autor(es)

Figueiredo, Felipe Torres ^[1] ; de Almeida, Renato Paes ^[1] ; Tohver, Eric ^[2] ; Babinski, Marly ^[3] ; Liu, Dunyi ^[4] ; Fanning, Christopher Mark ^[5]

Afiliação do(s) autor(es)

^[1] Univ Sao Paulo, Inst Geociencias, Dept Geol Sedimentar & Ambiental, BR-05508080 Sao Paulo - Brazil

^[2] Univ Western Australia, Sch Earth & Geog Earth Sci, Crawley, WA 6009 - Australia

^[3] Univ Sao Paulo, Inst Geociencias, Ctr Pesquisas Geocronol, BR-05508080 Sao Paulo - Brazil

^[4] Chinese Acad Geol Sci, Beijing SHRIMP Ctr, Beijing 100037 - Peoples R China

^[5] Australian Natl Univ, Res Sch Earth Sci, Canberra, ACT - Australia

• Tipo de documento: Artigo Científico
• Fonte: TERRA NOVA; v. 21, n. 5, p. 375-385, OCT 2009.
• Citações Web of Science: 14

Resumo

One of the main questions on Neoproterozoic geology regards the extent and dynamics of the glacial systems that are recorded in all continents. We present evidence for short transport distances and localized sediment sources for the Bebedouro Formation, which records Neoproterozoic glaciomarine sedimentation in the central-eastern Sao Francisco Craton (SFC), Brazil. New data are presented on clast composition, based on point counting in thin section and SHRIMP dating of pebbles and detrital zircon. Cluster analysis of clast compositional data revealed a pronounced spatial variability of clast composition on diamictite indicating the presence of individual glaciers or ice streams feeding the basin. Detrital zircon ages reveal distinct populations of Archean and Palaeoproterozoic age. The youngest detrital zircon dated at 874 +/- 9 Ma constrains the maximum depositional age of these diamictites. We interpret the provenance of the glacial diamictites to be restricted to sources inside the SFC, suggesting deposition in an environment similar to ice streams from modern, high latitude glaciers. (AU)

• Processo FAPESP: 06/61433-8 - Analise de sistemas deposicionais e proveniencia dos diamictios das formacoes bebedouro (centro-norte do estado da bahia) e jequitai (nordeste de minas gerais): um estudo da dinamica glacial neoprotero..
• Beneficiário: Renato Paes de Almeida
• Modalidade de apoio: Auxílio à Pesquisa - Regular