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Relações entre orógenos, zonas de cisalhamento, quebra continental e deformações 3-d. a história tectônica da Bacia Sedimentar de Almada, Bahia

2005; Sociedade Brasileira de Geologia; Volume: 35; Issue: 4 Linguagem: Inglês

10.5327/rbg.v35i4.1212

2317-4889

Luiz César Corrêa-Gomes, José Maria Landim Domínguez, Johildo Salomão Figueirêdo Barbosa, Idney Cavalcanti da Silva, Moises Vieira Pinto,

Geological and Geochemical Analysis

The Almada Basin is a geometric out-pattern member in the group the onshore coastline sedimentary basins of the Bahia State and neighborhoods. This basin differs from the traditional elongated-shape trending Camamu and Reconcavo- Tucano-Jatoba basins, and shows a compact rhombohedral arrangement following N45 o , N90 o , N120 o e N-S structural lineaments. This shape directly or indirectly reflects a specific geological history influenced by the paleoproterozoic and neoproterozoic orogens, neoproterozoic shear zones and mesozoic supercontinent break-up. Several sets of fault and fractures were kinematically studied inside and around the basin, and the main stress tensors obtained using inversion methods. The structural study of the Almada Basin allowed to recognize that: (i) the initial tectonic activity was controlled by normal faults, with orthorhombic-romboedral 3-D extensional strain pattern, followed by transtensional ones characterizing the Almada Basin as a polyphasic tectonic basin, and (ii) during the transtensive phase this basin was affected by at least two almost orthogonal extensional events, indicating a possible o 1 orientation inversion during its formation and tectonic evolution. These data are crucial for prospecting groundwater and hydrocarbon in the basin onshore and offshore areas.