Rajmahal Traps

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Rajmahal Hills

The Rajmahal Traps is a volcanic igneous province in

Rajmahal Hills of Jharkhand is the type area of this province. Multiple layers of solidified lava made the 608-metre-thick (1,995 ft) Rajmahal Traps which are dipping 2–5° towards the north-east. Individual layers vary in thickness from less than one metre (3 ft 3 in) to more than 70 metres (230 ft).[1]

Genesis

These volcanic rocks were formed from the eruptions over the Kerguelen hotspot in the early Cretaceous.[2] The similarity between the geochemical data of Rajmahal volcanos and lavas of the Kerguelen Plateau confirms this. According to plate tectonics, the Indian subcontinent was over this hot spot during the Cretaceous Period.

The original lava flow covered an area of nearly 4,100 km2 (1,600 sq mi). Below the Bengal basin the flows cover 200,000 km2 (77,000 sq mi).[3]

Lithology

The Rajmahal volcanics are predominantly

claystone and shale.[1]

Structural evolution

The western boundary of the Rajmahal Traps is faulted and down-thrown towards the east. The eastern boundary of this trap has a North-South trending, fault-controlled basement. This basement connects the Purnea basin of the Ganga valley with the Bengal basin. These faulted contacts, along with the Damodar Gondwana

Gondwanaland. Over the epochs, the upper part of the lava deformed in a cold, brittle fashion and formed graben structures.[3]

Fossils

The

plant fossils
. The assemblage includes Cladophlebis indica, Dictyozamites indicus, Taeniopteris spatulata, and Brachyphyllum rhombium.

See also

References

  1. ^
    ISBN 978-0230-32833-4
    .
  2. ^ Courtillot, Vincent. Evolutionary Catastrophes: The Science of Mass Extinctions. Cambridge, Cambridge University Press, 1999; p. 95.
  3. ^
    S2CID 129952630
    . Retrieved 8 March 2017.
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