Fácies sedimentares da Formação Lagarto, Pré-Cambriano Superior no extremo nordeste da Bahia
1983; Sociedade Brasileira de Geologia; Volume: 13; Issue: 4 Linguagem: Inglês
10.25249/0375-7536.1983134263270
ISSN2177-4382
AutoresGerson Souza Saes, Geraldo da Silva Boas,
Tópico(s)Paleontology and Stratigraphy of Fossils
ResumoThe metasediments of the Lagarto Formation, Estância Group, which outcrop in the northeastern region of the State of Bahia, constitute a terrigenous sequence exhibiting sedimentary facies strongly suggestive of deposition in tidal flat, shoreface, and shelf environments. The basal portion of the section consists of tidal flat interlayered red siltstones and shales forming typical prograding sequences. Green siltstone shelf deposits transgressive over the basal prograding sequences dominate the medium portion of the formation and are interpreted as deposited during periods of high sediment influx related to seasonal changes. This portion also includes local rythmites with gradational lamination and sandstones with hummocky structures, indicating deposition under stormy conditions. The upper portion of the formation is characterized by tidal flat/shoreface deposits composed of interbedded siltstones, shales and sandstones reflecting alternating regressive (prograding) and transgressive cycles.
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