The
Tectono-Sedimentary Evolution of NW
Watkinson, Matthew P.1, Edward
P. Blunt2, Mark A. Enfield3 (1) PDF Fellowship,
University of Plymouth, Plymouth, United Kingdom (2) Sterling Energy plc,
Harpenden, United Kingdom (3) PDF Ltd, Streatley, United Kingdom
The offshore basins of NW Madagascar
present a significant frontier exploration challenge as a result of their
complex geological evolution and a relative paucity of subsurface data. Exploration
risk is being constrained through the integration of analyses of onshore
geology and seismic sequence stratigraphy with an evaluation of the tectonic
evolution of the southern
The tectono-stratigraphy of NW Madagascar
comprises seven megasequences. These can be related to Karoo extensional
tectonics, Early Jurassic rifting between East Africa and Madagascar, opening
of the Somali Basin-Mozambique Channel, mid-Cretaceous strike-slip tectonics,
Late Cretaceous rifting between India/Seychelles and NE Madagascar and
subsequently changes in the location and vectors of ocean spreading in the
Indian Ocean during latest Cretaceous/Paleocene and the Cenozoic. The presence
and distribution of these megasquences and the structural styles associated
with them have been confirmed through a detailed evaluation of the onshore
geology of NW Madagascar, including fieldwork.
The application of the
tectono-stratigraphic framework to exploration offshore has been facilitated
through analysis of a seismic database which has been significantly improved by
reprocessing and new acquisition. And the sequence stratigraphic and structural
interpretation of seismic data has provided new insights into the link between
tectonics, salt behaviour and the nature and distribution of key play elements
of the basins.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California