There are various forces that act upon the plates to make them move. Three possible mechanism of plate motion – Convectional Currents :- Slab Pull :- Slab pull is thought to operate at subduction zones where the subducting oceanic plate becomes colder and denser than the surrounding mantle (gabbro metamorphosed into eclogite) and pulls the […]
CAUSES OF PLATE MOTION Read More »
Ichno-fossils are an expression of the alteration of the depositional fabric in sedimentary rocks by living organisms. Often these expressions are part of animal behavior or traces hence called “trace fossils”. Common structures are burrows, boring, trails and tracks. Trace fossils can be common in un-fossiliferous rocks, that can extend the geologists capability to interpret
A metamorphic facies series is a sequence of facies that occurs across a metamorphic terrane due to differences in pressure and temperature (P/T) conditions. Each facies series is characterized by the development of a particular sequence of individual facies, with each facies stable at a specific range of temperature and pressure conditions High P/T series
Metamorphic facies series Read More »
Alkaline rocks occur in all tectonic environments, including the ocean basins. Alkaline rocks are generally considered to have more alkalis than can be accommodated by feldspars alone. The excess alkalis then appear in feldspathoids, sodic pyroxenes/amphiboles or other alkali-rich phases. Alkaline rocks generally occurs in three principal settings :- Some important igneous Alkaline rocks are
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
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.
CITZ (Central Indian Tectonic Zone) Read More »
