Produção Nacional
A GLACIAÇÃO NEOPALEOZÓICA NA PORÇÃO MERIDIONAL DA BACIA SANFRANCISCANA
1994; Sociedade Brasileira de Geologia; Volume: 24; Issue: 2 Linguagem: Inglês
10.5327/rbg.v24i1.492
ISSN2317-4889
AutoresJosé Elói Guimarães Campos, Marcel Auguste Dardenne,
Tópico(s)Geography and Environmental Studies
ResumoThis text represents a stratigraphic and environmental study of two areas in the northwest of Minas Gerais State, Brazil. The work allowed the identification of the Permo-Carboniferous glaciation in the Sanfranciscana Basin, not yet described. A stratigraphic subdivision is proposed for the glaciogenic strata - The Santa Fe Group - which is composed of the Floresta and Tabuleiro Formations. The Floresta Formation is the basal unit and is composed of three members: Brocoto Member (tillites and tilloides), Brejo do Arroz Member (red mudstones and siltstones with a variety of dropstones) and Lavado Member (red sandstones). The Tabuleiro Formation (homogeneous sandstones) overlies all members of Floresta Formation. The arkoses of the Tres Marias Formation (Upper Proterozoic) are the regional basement for the glaciogenic sequence. The Santa Fe Group is a proglacial system with tillite and tilloide facies (Brocoto Member), fluvioglacial facies (Lavado Member), glacio-lacustrine and turbiditic facies (Brejo do Arroz Member) and periglacial eolian facies (Tabuleiro Formation). The glacial sedimentation was controlled by the advance and retreat of the ice sheet. Diagenetic reactions are not well developed because of the incipient burial history. The major diagenetic feature was a calcitic pervasive cementation. The provenance areas for the glaciogenic deposits are interpreted from heavy mineral analysis, striated pavement orientation and dropstone composition. The northern Espinhaco region is proposed as the source area.
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