The Amazon Fan, located in the deep-sea Foz do Amazonas Basin on the Brazilian Equatorial Margin, is one of the largest submarine fan systems in the world. It´s most important features are shale diapirism and a linked extensional-compressional system on a basal detachment. In this paper, we re-interpreted six seismic reflection lines to provide new insights into the gravity tectonics of controversial age. On seismostratigraphic data, we recognized the acoustic basement and six sedimentary units. Extensional faults rooting into a detachment revealed seaward decreasing age, pre- to syn-tectonic with respect to the gravity sliding, and rare activity in the faults at present. For basal detachment became active during Mioceno Superior. Suggested is the basal portion of the paleocenic Travosas Formation that in consequence of an overload caused by the deposition of the Pará Group.
Foz do Amazonas Basin; Amazon Fan; seismostratigraphic data; basal detachment; Travosas formation
