STRATIGRAPHY ARTICLES Archives

Gondwana S.G. (Damodar, Satpura, Mahanadi & Godavari basin)

GEO-ARTICLES, STRATIGRAPHY ARTICLES / OPEN GEOLOGY

Gondwana Supergroup is made up of continental sediments that were deposited in fluvial and lacustrine basins in different parts of the Indian Peninsula. This deposition begins from Late-carboniferous/ Early Permian (300 Ma) and continued until the Early Cretaceous Epoch (100 Ma). Lower part of the Gondwana sequences contain rich coal deposits. Barakar formation is the

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Mesozoic of SPITI

GEO-ARTICLES, STRATIGRAPHY ARTICLES / OPEN GEOLOGY

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

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Magnetostratigraphy

GEO-ARTICLES, STRATIGRAPHY ARTICLES / OPEN GEOLOGY

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

GEO-ARTICLES, STRATIGRAPHY ARTICLES / OPEN GEOLOGY

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

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Paleozoic of Spiti

GEO-ARTICLES, STRATIGRAPHY ARTICLES / OPEN GEOLOGY

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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Chronostratigraphy

GEO-ARTICLES, STRATIGRAPHY ARTICLES / OPEN GEOLOGY

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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Lithostratigraphy

GEO-ARTICLES, STRATIGRAPHY ARTICLES / OPEN GEOLOGY

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.

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North Singhbhum Mobile Belt [NSMB]

GEO-ARTICLES, STRATIGRAPHY ARTICLES / OPEN GEOLOGY

The North Singhbhum Mobile Belt (NSMB) is a multiple folded, low to medium grade meta-sedimentary and meta-igneous rocks of Proterozoic age (1.0–2.4 Ga) sandwiched between the Archaean (>2.4 Ga) Singhbhum Craton in the south, and the Meso/Neo-Proterozoic (0.9–1.7 Ga) Chotanagpur Gneissic Complex (CGC) in the north by north-dipping ductile shear zones. Clastic sediments with minor volcanics comprising the

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Global Boundary Stratotype Sections and Points (GSSP)

GEO-ARTICLES, STRATIGRAPHY ARTICLES / OPEN GEOLOGY

“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

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Cenozoic deposits of Himalaya

GEO-ARTICLES, STRATIGRAPHY ARTICLES / OPEN GEOLOGY

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

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