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SISTEMAS DEPOSICIONAIS DA CHAPADA DIAMANTINA CENTRO-ORIENTAL, BAHIA

1997; Sociedade Brasileira de Geologia; Volume: 27; Issue: 3 Linguagem: Inglês

10.25249/0375-7536.1997229240

2177-4382

Augusto José Pedreira,

Soil Management and Crop Yield

CHAPADA DIAMANTINA, BAHIA The Mesoproterozoic sedimentary rocks cropping out in the Central-eastern Chapada Diamantina, Bahia, forming a Q-P-C (Quartzite-Pelite-Carbonate)Association, comprise twelve distinct conglomerate, sandstone and carbonate lithofacies.The lithofacies are composed of 1) conglomerates both clast and matrix supported; 2) coarse, medium, fine grained and bimodal, paraiel bedded and trough, tabular and herring bone cross bedded sandstones, 3) graded sandstones and, 4) carbonates, algal laminites and dolarenites.These lithofacies are assembled into alluvial fan, fluvial, desertic, tidal flat, deltaic and marine depositional systems, alternating along the stratigraphic column.The onset of the sedimentation is continental, represented by desertic, alluvial fan and fluvial systems that progressively changes to a deltaic system, typical of a continental margin.A western source area is proposed, based on paleocurrent data.Overlying the deltaic system, occur continental and marine depositional systems with an eastern provenance because of basin tilting, suggested by paleocurrent inversion.The analysis of these systems hás allowed the reconstitution of the tectonic evolution of the region, that begins by deposition on a stable cratonic area, followed by the establishment of a foredeep.