“A Stratotype or type Section is a geological term that names the physical location or outcrop of a particular reference exposure of a stratigraphic sequence or stratigraphic boundary.” Classification of Stratotypes : GSSP (Global Boundary Stratotype Sections and Point) A GSSP is an internationally agreed upon stratigraphic section which serves as the reference section of […]
Global Boundary Stratotype Sections and Points (GSSP) Read More »
The Outer or Sub-Himalaya is the main zone of the Cenozoic sedimentation. The Paleogene-Neogene sequences of the Sub-Himalaya occurs in the northern states of India. The Subathu, Murree and Dharamshala are the main Paleogene groups of rocks where Siwalik is a major Neogene group of Cenozoic sequences of the Sub-Himalaya. Other deposits belongs to the
Cenozoic deposits of Himalaya Read More »
An unconformity is a plane of discontinuity that separates two rocks, which differs in age. The younger of these rocks are nearly always of sedimentary origin and must have been deposited on the surface of the older rock, which is a surface of erosion. Formation of unconformity : The formation of unconformity may be defined
The structure of the Dharwar Craton is interpreted in terms of a foreland in the west and an accretionary complex in the east. The older sequence that shows a relatively higher degree of metamorphism and intrusive contact with the granitic and gneisses has been named as Sargur Group. The granitic gneisses that show intrusive contact
The Cretaceous rocks consists of thick succession of marine sequences that ranges in age from Aptian to Maastrichtian. The marine sequences represents at least four phases of marine transgression that were interrupted by brief periods of withdrawal of marine conditions. The marine transgression leads to the deposition of four groups as Dalmiapurum, Uttatur, Trichinopoly and
Cauvery Basin (Cretaceous of Trichinopoly) Read More »
Mesozoic rocks of kutch were deposited in rift basins that developed during the Late Triassic (Rhaetian). The basin was filled with syn-rift Middle Jurassic to Early Cretaceous sediments and post-rift Late Paleocene to Pliocene and Quarternary sediments. The Mesozoic marine sediments show characters of siliclastic ramp, carbonate ramp, storm dominated shallow shelf carbonates, and fine
Jurassic of Kutch Read More »
The fossiliferous Lower Paleozoic rocks either rests conformably over the un-fossiliferous sequence named as Dogra Slate or unconformably over the crystalline rocks comprising Salkhala Group. The succession begins with Hapatnar Group of Late Cambriam to Silurian age which is overlain successive formations of Middle and Upper Paleozoic. Stratigraphy of the area :- Stratigraphic Unit Lithology
Paleozoic of Kashmir Basin Read More »
Precambrian basement of central India is made up of two cratonic domains, the Aravalli-Bundelkhand craton in the North and Bastar craton in the South. They are separated by a ENE-WSW trending Narmada-Son lineament. This zone has been named as Central India Tectonic Zone. CITZ contains fragments of both, the northern and the southern cratonic domains.
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The Vindhyan Supergroup is named after the scarped plateau mountains in the north of the Narmada Valley. Vindhyan basin is canceled under the Deccan Traps of the Malwa Plateau and the Quaternary sediments. The basin evolved as a vast intra-cratonic basin formed in response to intraplate stresses. The Vindhyan Basin was formed as a result
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The Neogene rocks are exposed in the Siwalik Hills and other foot hill comprising the Outer Himalaya. Siwalik group is a thick succession of medium to coarse sandstone, conglomerate and clay. Base is not exposed.
