The Geology of Burma - Zomi Online Library

Bibliography of Burman Earth Science
basement. With the breakup of Gondwanaland in the Jurassic and
Cretaceous, and northward movement of the Indian Plate, the basin
started down warping in the Early Cretaceous and sedimentation
started on the stable shelf and deep basin; and since then
sedimentation has been continuous for most of the basin. Subsidence
of the basin can be attributed to differential adjustments of the crust,
collision with the various elements of south Asia, and uplift of the
eastern Himalayas and the Indo-Burman Ranges. Movements along
several well-established faults were initiated following the breakup of
Gondwanaland and during down warping in the Cretaceous. By
Eocene, because of a major marine transgression, the stable shelf
came under a carbonate regime, whereas the deep basinal area was
dominated by deep-water sedimentation. A major switch in
sedimentation pattern over the Bengal Basin occurred during the
Middle Eocene to Early Miocene as a result of collision of India with the
Burma and Tibetan Blocks. The influx of clastic sediment into the basin
from the Himalayas to the north and the Indo-Burman Ranges to the
east rapidly increased at this time; and this was followed by an
increase in the rate of subsidence of the basin. At this stage, deep
marine sedimentation dominated in the deep basinal part, while deep
to shallow marine conditions prevailed in the eastern part of the basin.
By Middle Miocene, with continuing collision events between the plates
and uplift in the Himalayas and Indo-Burman Ranges, a huge influx of
clastic sediments came into the basin from the northeast and east.
Throughout the Miocene, the depositional settings continued to vary
from deep marine in the basin to shallow and coastal marine in the
marginal parts of the basin. From Pliocene onwards, large amounts of
sediment were filling the Bengal Basin from the west and northwest;
and major delta building processes continued to develop the presentday
delta morphology. Since the Cretaceous, architecture of the
Bengal Basin has been changing due to the collision pattern and
movements of the major plates in the region. However, three notable
changes in basin configuration can be recognized that occurred during
Early Eocene, Middle Miocene and Plio-Pleistocene times, when both
the paleogeographic settings and source areas changed. The present
basin configuration with the Ganges-Brahmaputra delta system on the
north and the Bengal Deep Sea Fan on the south was established
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