G. Lakshminarayana, GONDWANA SEDIMENTATION IN THE CHINTALAPUDI SUBBASIN GODAVARI VALLEY, ANDHRA-PRADESH, Journal of the Geological Society of India, 46(4), 1995, pp. 375-383
A 3000 m thick Gondwana lithic fill consisting of multifacies associat
ions were preserved in a NW-SE oriented intracratonic Chintalapudi sub
-basin set across the Eastern Chat Complex (EGC). Sedimentation commen
ced with the deposition of diamictite-rhythmite sequence of the Talchi
r Formation in glacio-lacustrine environment. The succeeding sandstone
-coal cyclothems of the Barakar Formation were formed in fluvial-coal
swamp complex. The fluvial streams flowed across the EGC, originating
somewhere in the southeast beyond the East Coast of India. Phase wise
upliftment of the EGC during Mesozoic imparted changes to the Permian
intercontinental drainage system which started supplying increased amo
unt of detritus to the basin. Basin marginal faults were first formed
at the beginning of Triassic. Alluvial fans originated in the east and
southeast and northwesterly flowing braided streams deposited the con
glomerate sandstone sequence of the Kamthi Formation. The Early Jurass
ic uplift of the Mailaram high in the north imparted westerly shift to
the braided rivers during the Kota sedimentation. Due to prominence o
f Kamavarapukota ridge in the south by Early Cretaceous, the drainage
pattern became centripetal and short-lived high sinuous rivers debouch
ed into the basin. The silting up of the Chintalapudi sub-basin with t
he sandstone-claystone sequence of the Gangapur Formation marks the cu
lmination of the Gondwana sedimentation, perhaps, coinciding with the
breakup of India from the Gondwanaland.