Three major cycles of deposition have been found in the sedimentary records of the Mesozoic formations of the Spiti Basin. All other formation and beds are collectively known as Kibber Group. “The Kioto -Spiti Shale contact represents a hiatus from Late Callovian to Early Exfordian” The Spiti Shale demarkates the Jurassic age. The lowermost unit […]
Magnetostratigraphy is based on the polarity of the earth’s magnetic field as it is preserved in the sediments at the time when they were deposited. The magnetic minerals in the sediments orient themself in the direction of earth’s magnetic field and preserved. The earth’s magnetic poles have switched their position periodically in the geological past
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Biostratigraphy deals with the classification and correlation of rock strata based on their fossil contents. Fossils help in assigning relative ages to stratigraphic units can be correlated with different parts of the world. The biostratigraphy is based on the concept that there is evolutionary changes in the flora and fauna which if unidirectional. These animals
The Continuous Paleozoic succession is beautifully exposed in the area of Spiti valley. A rich collection of fossils reported from the region has made Spiti valley a standard sections for correlation of Phanerozoic rocks of Indian and adjoining regions of the sub-continent. There are three more groups naming Sanugba Group, Kanawar Group and Kuling Group.
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Any natural phenomena that obey a definite law of flow rate can be used to mark off certain intervals of time that can serve as a ‘clock’. The basic unit of time is second which. The other method that is commonly used by geologists is the subdividing time according to non-equal time intervals determined by
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We can classify the layered rock sequences primarily on the basis of their lithological characters. This scheme of classification is known as Lithostratigraphic Classification. “A bed or lamina represents a uniform condition of deposition in a basin.” A formation may comprise a single predominant rock type or an association of two or more rock types.
Feldspar are the most common rock forming minerals of the Earth’s crust Structure Classification Physical Properties Optical Properties Under PPL Under XPL Varities : Some advanced material Occurrance : Uses of feldspar :
Amphiboles are the common constituents in both Igneous and Metamorphic rocks. General formula of Amphiboles is , W0-1X2Y5(Z8O22)(OH,F)2 Structure Amphiboles Classification Orthorhombic amphiboles Triclinic amphiboles Monoclinic amphiboles General Physical and Optical properties Physical Properties Optical properties
a new species is created when a group of organisms within a species separates and develops unique characteristics. The new species is generally distinct from the original species and can no longer interbreed with it. ‘The process of transformation of species into new one with the accumulation of variations in time is known as speciation.’
Important minerals Types of Deposits :- Indian occurances :- Process of extraction :- The mining is both manual as well as by hydraulic dredging. The beach sand after sun-drying is fed to electromagnetic and electrostatic separators in a processing plant for physical separation of various mineral constituents. Alteration :- Leucoxene is a fine grained alteration
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