T. K. Schümann1, N. Ellouz2, K. Hinz3, Peter Gerling4, H. Meyer3
(1) Federal Institute for Geosciences and Natural Resources (BGR), presently at Institut Français du Pétrole (IFP), 92852 Rueil-Malmaison Cedex, France
(2) Institut Français du Pétrole (IFP), 92852 Rueil-Malmaison Cedex, France
(3) Federal Institute for Geosciences and Natural Resources (BGR), 30655 Hannover, Germany
(4) Federal Institute for Geosciences and Natural Resources (BGR), Hannover, Germany
ABSTRACT: The Argentine Passive Continental Margin - Basin Modeling Using New Seismic Data
The study area is located offshore Argentina and comprises the outermost shelf, the slope, the rise and even the abyssal plain, and includes the seaward extension of the Colorado Basin. From 1987 to 1999 the Federal Institute for Geosciences and Natural Resources (BGR) measured approximately 15.000 km of multichannel 2-D seismic lines, mostly traversing across the Argentine continental margin.
In the Late Jurassic / Early Cretaceous times, continental breakup of Gondwana led to the opening and northward propagating of the South Atlantic. Since 135Ma, the Paraná-Etendeka continental flood basalts were emplaced, associated with seaward-dipping reflectors (SDRS), possibly related to the Tristan da Cunha hot spot. After breakup, thermal subsidence affected predominantly the development of the volcanic continental margins, especially the elongated SDRS zone. A thick sedimentary column (up to 6000 m) was deposited onto the transition zone between the continental and the marine crust mainly during the period of thermal sag.
Based on seismic interpretation, IFP software was used to model the subsidence of the transition zone in order to establish thermal history, tectonic evolution, sedimentary distribution as well as an estimation of compaction and erosion processes. Further modelling was applied using lithological concepts derived from seismic facies analysis and available well data. Modelling the thermal history of the sedimentary pile led to a model of the maturity of the potential source rocks in the deep domain of the South Atlantic region (mainly black shales correlated to Cretaceous anoxic events). To model the migration paths a 2-D approach was attempted.
AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado