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Photograph
shows the Geological Survey of Pakistan rig being operated at Thatta
close to the head of the Indus delta. Coring penetrated to around 30 m
depth in this location, recovering a sequences of sands and minor
clays, deposited by the paleo-Indus, whose modern channel lies ~3 km
away.
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Example of marine muds recovered
by coring operations at Keti Bandar, close to the coast. The
shallowest levels of the delta top appeared to be a mixed sand and clay
sequence, overlying a homogenous clay unit. The clays showed
minor bioturbation and the frequent occurence of bivalve shells, such
as the small white one seen in this example. Coring at Keti Bandar
recovered almost 140 m of sediment below the surface.
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The base of
the marine clays at Keti Bandar was marked by a sharp transition, shown
here into coarse sands. These were massive or parallel laminated
and coarsen rapidly at the top before the clay transgression.
Carbon dating of the shells in the sediments will allow the age and
rates of sedimentation to be assessed.
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Team of scientists from NIO,
University of Karachi and Woods Hole recover a vibrocore from the tidal
flats close to Keti Bandar, just north of the modern active channel of
the Indus. The delta top is often clay-rich, making vibrocoring
difficult, yet below the top 3-5 m the sediments are often sandy and
readily recovered by this method.
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