Journal of Geology & Geophysics
Open Access

Geological and structural mapping of eastern sector of the Cribas anticline: The influence for the hydrocarbons genesis

International Conference on Geology

June 22-23, 2015 Florida, USA

Valente Ferreira

Posters-Accepted Abstracts: J Geol Geosci

Abstract :

Several geological formations were mapped in eastern Cribas namely the Lower Permian Atahoc Formation, Upper Permian Cribas Formation, Triassic Aituto Formation, Post- Pliocene Ainaro Gravel and the Recent Alluvial Deposits. All these formations are mostly employed by sedimentary rocks such as clastic and carbonates rocks except the Ainaro Gravel which filled by gravel grains such as coarse conglomerates of the Lolotoi Complex pebbles in an argillaceous matrix. The Atahoc and Cribas formations are separated by a basalt sill associated with red marls and marlylimestones. Regarding the structures, there are two deformation phases in the eastern Cribas are D1 and D2. The D1 induced the generalized folding of the region including the major Cribas anticline and it is an open fold with an E-W sub-horizontal axis and limbs dipping 25º N-S. The most important D2 structures are major N-S sinistral strike-slip faults and coeval minor folds. In Hacraun River, it is possible to emphasize that while the D1 folds have sub-vertical axial planes, the D2 ones are mainly sub-horizontal. Concerning the main D2 N-S faults, it should be emphasized the one developing along the Sumasse River (western of Cribas region) and the ones developing at the Hacraun River (N Hacraun fault and S Hacraun fault). As it is usual in the structural environments where the strike-slip predominates, there is a diversity of D2 accommodation structures, it must be emphasized a south vergence E-W thrust affecting the core of the Cribas anticline and the NE-SW Tuqueti one which induced the thrusting of the Aituto formation by the Cribas formation. These structures induced oil seeps in the eastern side of the Tuqueti River. Geochemical analyses of shales rocks samples of the Cribas Formation show 0.71% of Total Organic Carbon (TOC) which means that this rock will probably be a source rock for hydrocarbons. The studied shales of the Atahoc and Aituto Formations show the TOC values are below 0.71%.