Microbialitos fósseis da formação Jaíba, grupo Bambuí, Minas Gerais, Brasil.
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Date
2018
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Abstract
Microbialites are carbonatic deposits,
whose genesis is organosedimentary, deposited by benthic microbial mats. Microbialites are the most common fossils in rocks of the Proterozoic,
worldwide and in Brazil. They exhibit morphological diversity since the oldest Archean forms, and are fundamental in studies concerning the
biota and environmental aspects of past times, allowing better comprehension of biological and carbonate biosedimentary evolution through
time. Microbial laminites and thrombolites of the Jaíba Formation, upper Bambuí Group, are described. Thrombolites show columnar and
irregular shape, centimetric size, and are locally coalescent. Laminites, overlying the thrombolitic strata, display smooth, wavy, and crenulate
synoptic relief. Five microfabrics and microfossils of two distinct morphologies, coccoidal and filamentous, were identified. Microfabrics
may be of biogenic or abiogenic origin, representing different processes involved in the formation of microbialites. Thus, microbialites
and microfossils of the Jaíba Formation show potential to better understand the producer biota in the context of the Ediacaran-Cambrian
transition, probable age of this unit, and an important moment of profound changes in biosphere, due to the diversification of metazoans.
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Keywords
Trombólitos, Laminitos microbiais, Texturas, Neoproterozoico, Cambriano
Citation
SANCHEZ, E. A. M. et al. Microbialitos fósseis da formação Jaíba, grupo Bambuí, Minas Gerais, Brasil. Revista Brasileira de Paleontologia, v. 21, p. 175-186, 2018. Disponível em: <http://www.sbpbrasil.org/assets/uploads/files/rbp2018207.pdf>. Acesso em: 08 fev. 2019.