Abstract:
Camamu Graben corresponds to the southern portion of a connected graben system bounded by Margogipe’s Fault System. Structural and stratigraphic evidences reveal that the deposits within this graben were controlled by rift related tectonics. Stratigraphic analysis allowed the recognition of two unconformity-bounded sequences. The base of Sequence I is composed by alluvial fans coming from the east margin and deposited during basement rotation. These systems were dominated by gravitational flow or braided channels, with subordinated aeolian dunes. The main drainage was characterized by a deep braided channel system, which flowed eastward, transposing the structural high of the east margin. The agradational stacking pattern and the fluvial architectural characteristics marks a low accommodation systems tract. Above these deposits takes place a distributary fluvial system, characterized by mixed load rivers and in its distal portion by sheet floods in a muddy flood plain with ephemeral lakes. The retrogradational stacking pattern is attributed to an increase on subsidence rates. Sequence II marks the ongoing of the distributary system basinward after a generalized erosion of theflood plain deposits caused by a base level fall. This sequence is composed by bed load channels interlayered with sandy sheet floods and subordinated aeolian dunes. The fluvial architecture and the agradational stacking pattern suggest low accommodation conditions.
Keywords:
Camamu Basin; rift; stratigraphy