Geology Reference
In-Depth Information
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Contd
.)
(a) Fluvio Glacial
deposits
Pleistocene to
Recent
The morainic deposits occupy valleys and gorges in
interior Himalayas. Karewas (Kashmir Valley) are
lacustrine deposits displaying cyclic layers of clayey, silty
and coarser deposits with intervening boulder beds.
Locally significant hydrogeological potential.
(a) Mixed Boulders, Cobbles,
Sands and Silts
(b) Glacio-Lacustrine
deposits
(b) Conglomerates, Sands Gravels,
Carbanaceous shales and Blue
Clays.
The Bhabhar piedmont bell contains many productive
boulder-cobble gravel-sand aquifers. The water table is
deep. Forms recharge zone for deeper aquifers of alluvial
plains in south. Tarai belt is down-slope continuation of
Bhabhar aquifers. The deeper confined aquifers display
flowing artesian conditions. Shallow water table yields
up to 28 lps.
(c) Piedmont and
Himalayan Foot
Hill deposits
(c) Boulders, Cobbles, Pebble
Beds, Gravels, Sands, Silt and
Clays.
(d) Alluvial Plains
(Older and
Newer Alluvium)
(d) Clays and Silts, Gravels and
Sands of different mix. Lenses
of Peat and Organic matter,
Carbonate and Siliceous
Concretions (Kankar).
Occur widespread in the Indo-Ganga-Brahmaputra alluvial
plains. Form the most potential groundwater reservoirs
with a thick sequence of sandy aquifers down to great
depths.
The unconfined sand aquifers sometimes extend down to
moderate depth (125 m). Deeper aquifers are leaky-
confined/confined. The older alluvium is relatively
compact. The unconfined aquifers generally show high
storativity (5 to 25%) and high transmissivity (500 to
3000 m
2
/day).
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Contd
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