Seismic Stratigraphic Analysis of the Punta Del Este Basin, Offshore Uruguay, South America (1)

Abstract

The Punta del Este basin of offshore Uruguay is one of a series of Mesozoic sedimentary basins along the eastern seaboard of South America. The basin resulted from continental rifting of an older Gondwana landmass; this rifting led to the initiation of the South Atlantic Ocean. The tectonic and stratigraphic history of the basin can be characterized by a three-phase evolution, with each phase involving a separate and distinct basin geometry, style of faulting, and lithostratigraphic succession. The rift phase deposited predominantly continental siliciclastics of Neocomian age arranged in a number of syndepositional assymetric trap-door grabens. This phase is overlain by a largely unfaulted succession of continental to marine rocks of the Sag basin phase of Aptian to Maastrichtian age. These rocks record an overall marine transgression. The passive margin phase is represented by a thick sequence of Tertiary sediments that postdate rift-related tectonism and correspond to sedimentation along the margin of the newly opened South Atlantic Ocean. The Punta del Este part of the greater Salado basin is relatively unexplored with only two wells having been drilled, both in the updip part of the basin. These two wells have contributed some understanding of the stratigraphic succession but have failed to adequately assess the basin's true hydrocarbon potential. This paper constitutes one of the first detailed, comprehensive published accounts of this basin and is a prerequisite for future exploration in the area.