Reevaluation of
the Majunga and
Eisenstadt, Gloria1, Dave
Bushnell2, Barry Rodgers3, Jackie Reed4,
Alfred Berroteran4 (1) Weinman Geoscience, Dallas, TX (2) Weinamn
Geoscience, (3) Madagascar Oil Limited, (4) Weinman Geoscience,
Exploration opportunities exist in the
Majunga and
Structural analysis shows that
development of the western passive margin did not follow distinct phases of
rift, breakup and drift. Rather extension occurred along major basement faults
intermittently from Permo-Triassic to late-Jurassic times, with local
unconformities reflecting fault movement. In the
The impact of a
regional Upper-Jurassic/Lower Cretaceous bathyal shale has not been
fully recognized. The presence of this seal may have prevented vertical charge
into younger reservoirs from older source rocks, effectively horizontally
partitioning the stratigraphy into separate petroleum systems. Hydrocarbons
from the dominantly lacustrine, Permian Sakemena shale would be available to
laterally charge reservoirs in the deeper, older section. Hydrocarbons for the
shallower system could come from the organic rich upper Jurassic or shales
within the Cretaceous. The latter have been observed in outcrop and the former
are known regionally. Clastic and carbonate deep-water fan deposits within the
seal facies may constitute a new exploration opportunity that can be developed
using modern seismic technology.
AAPG Search and Discover Article #90063©2007 AAPG Annual Convention, Long Beach, California