Barra Nova Salt Domes Province, Espirito Santo Basin, Offshore Brazil: ABSTRACT

Abstract

The Barra Nova salt domes province, in the Espirito Santo basin, offshore Brazil, bears some resemblance to the interior basins of the Gulf of Mexico. Two main hypotheses try to explain the origin of the Barra Nova salt domes. (1) Since Aptian salt was overlain by uniform Albian platform, salt movement began as a consequence of the general eastward tilting of the basin which caused gravity sliding and the formation of salt pillows. (2) Existence of an uneven sedimentary loading is represented by Upper Cretaceous volcanic flows extending over the area underlain by salt. These volcanics sank into the salt, forming exposed salt masses which were dissolved, causing salt withdrawal and gravity sliding. Continued sedimentation on the evacuated areas induces the formation of sal domes. The initial salt pillows began forming during the Albian. Before the Maestrichtian, they reached the extrusion/collapsing phase which extended to the Holocene with the salt domes being dissolved on the present sea floor. One of the mapped domes represents an exception, as it seems to be already in the burying phase. The gravity sliding, originated from halokinesis, was an important factor in the tectono-sedimentary evolution of the Espirito Santo basin from Late Cretaceous on. End_of_Article - Last_Page 543------------