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Manju Banerjee ¹

Affiliations
1 Botany Department, University of Calcutta, Calcutta, IN

Abstract

No Abstract.

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Manju Banerjee ¹, Arghya K. Hait ²

Affiliations
1 Department of Botany, University of Calcutta, Kolkata - 700 019, IN
2 Department of Botany, City College, Kolkata - 700 009, IN

Abstract

Palynostratigraphic analyses of the Lower Gondwana sediments in the Saharjuri basin, Deoghar group of coalfields, Jharkhand recognize fifteen palynostratigraphic zones (PNSJ T, PNSJ 1 - XIV).The palynostratigraphic zones have been compared with the known lithostratigraphic zones of the basin and suggest upper Karharbari Formation for the Saharjuri coal seam nos. CH. I - II and Barakar Formation for the rest of the coalseams viz., Colony to Damagara CH.III- CH.XIV.

Each of the palynostratigraphic zone represents a characteristic ecological phase of deposition. The palynostratigraphic zones have been identified on the basis of the stratigraphically restricted occul-rence of quantitatively dominant and qualitatively significant taxa in the palynoassemblages. Altogether fifteen such zones are recognised viz., Ecol. Ph. PNSJ T and I-XIV. These fifteen Eco- palynostratigraphic zones were deposited under the influence of major climatic phases viz. cool climatic phase (C1. Ph. I), temperate climatic phase (C1. Ph. II) and warm climatic phase (C1. Ph. III). The temperate climatic phase C1. Ph. II is the most prolonged phase of deposition in the Saharjuri basin; this phase however has record of three minor but distinct sub-phases of climatic fluctuations. The sub-phases are stratigraphically restricted and represent characteristic palynoassemblages. One of the ecological phases viz., Ecol. Ph, PNSJ XII is distinct from the other ecoassemblages in the qualitative and quantitative abundance of taxa of brackish to marine environment. This minor phase of deposition is identified as Marine Transgression in the essentially continental facies of deposition. The stratigraphic horizons with characteristic assemblage of clearly distinguishable minor Eco-Climatic zones are identified as 'Marker Horizons'.

The major and minor climatic phases, sub-phases, ecological phases of Marine Transgression, identified as the Marker Horizons in the Saharjuri basin closely correspond with the similar sequential changes of climatic and ecological phases of Marker Horizons in the adjoining Rajmahal basin and other basins of India and Early Permian of Bhutan in the eastern Indian subcontinent.

Keywords

Palynostratigraphy, Major-Minor Climatic- Ecological phases, Marine influence, Marker Horizon, Barakar Formation, Late Early Permian, Indian Lower Gondwana, Saharjuri basin, Jharkhand.

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Sudha Gupta ¹, Subir Bera ², Manju Banerjee ¹

Affiliations
1 Department of Botany, University of Calcutta, Kolkata - 700 019, IN
2 Department of Botany, University of Calcuttta, Kolkata - 700 019, IN

Abstract

Palynological investigation has been undertaken with tile subsurface Cenozoic sediments of Ganga basin to establish biostraligraphy and environment of deposition. Samples from four bore holes viz. Puranpur, Matera, Gandak and Raxaul under study have yieldcd palynomorphs and other microfossils. Palynoassemblage recovered from the older Cenozoic sedimcnts of thc four bore holes has becn analyzed in this paper to ascertain the age and environment of deposition. Rich palynoasscmblage recovered i'rorn the Ganga basin sediments compare closely with the palynoassemblage recovered from Palcoccne-Eocene sediments of other Tertiary basins in India. Occurrence of triporate 'Normapolles' type pollen grains in the assemblage is additional significant record. The palynoassemblage suggests a predominantly tropical warm humid climate with coastal brackish water influence. In addition, reworked microfossils of early and late Paleozoic, Mesozoic ages have becn recovered in the lower Tertiary palynoassemblage.

Keywords

Palynoassemblage, Palaeocene-Eocene, Reworked Palynomorphs, Ganga basin.

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