--> ABSTRACT: Petroleum Prospectivity of the Malvinas and Malvinas Plateau Basins, South Atlantic Ocean, by M. Dinkelman, J. Pinchin, J. Ross, M. Turic, and A. Nevistic; #91021 (2010)

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Petroleum Prospectivity of the Malvinas and Malvinas Plateau Basins, South Atlantic Ocean

DINKELMAN, MENNO, JOHN PINCHIN, JIM ROSS, MATEO TURIC, and ANTONIO NEVISTIC

The Malvinas Basin extends from the east flank of the Rio Chico High, offshore southernmost Argentina, to the Burdwood Bank, south of the Malvinas Islands. It developed mainly as a foredeep to the long active Samfrau Subduction Zone, and contains a great thickness (10,000 m) of Cretaceous to Tertiary sedimentary rocks. However, since the bulk of these sediments were deposited in post-Miocene time, they are thought to be thermally immature, especially in the south. The basin also contains pockets of Late Jurassic syn-rift sediments which probably are the principal source rocks for the oil discoveries in wells such as Salmon-1. Although Late Cretaceous and Tertiary structural and stratigraphic plays are recognized, the Late Jurassic to Early Cretaceous is considered to present the most attractive exploration plays in this Basin's relatively shallow waters.

The Malvinas Plateau Basin extends east-southeast from the Malvinas Islands towards the Ewing Bank and into water depths exceeding 3,000 m. Only the western margin of this basin has sufficient data for frontier exploration analysis. The basin developed as a passive margin to the South Atlantic Ocean from the Late Jurassic through the Early Tertiary. The sedimentary thickness is over 10,000 m, but thermally mature sediments are thought to lie only in deeper water beyond the 1,000 m isobath. Prospectivity in shallower waters would depend on lateral migration distances of 40 km or more to charge potential structural traps which have been observed on the existing seismic data.

A vast database, consisting of over 25,000 km of new and previously acquired seismic data, regional well data from adjacent and structurally analogous but offset areas, as well as regional geological data, was analysed and compiled for a fully integrated geological interpretation. The key factor in the prospectivity assessment of each basin is the nature and composition of their sedimentary columns in relation to their burial history. The resultant thermal maturity, in turn, is controlled by the tectonic history of the entire Malvinas Plateau region in general, and of each basin area in particular. 

AAPG Search and Discovery Article #91021©1997 AAPG Annual Convention, Dallas, Texas.