Title: Facies Analysis and Paleogeographic Implications of a Late Paleozoic Glacial Outwash Deposit, Bihar, India
Abstract:ABSTRACT Six interbedded facies are recognized in 60-m-thick, late Paleozoic Talchir strata exposed as a small outlier in Archean metamorphics in Bihar, eastern India. Conglomerate facies which occur ...ABSTRACT Six interbedded facies are recognized in 60-m-thick, late Paleozoic Talchir strata exposed as a small outlier in Archean metamorphics in Bihar, eastern India. Conglomerate facies which occur as elongate bodies and diamictite dispersed in small isolated blocks are interbedded with medium to coarse, massive, horizontal-bedded to cross-bedded sandstone and fine to medium ripple-laminated sandstone and laminated shale facies. A facies model derived from Markov chain analysis reveals a fining-upward relationship from conglomerate at base through sandstone to shale at top. Conglomerate facies which occur as elongate bodies, massive at base and cross-bedded at top, are similar to those of longitudinal bars of proglacial outwash plains. Small blocks of diamictite enclosed in conglomerate are interpreted as ice-rafted frozen blocks of moraine. Massive, horizontal-bedded to cross-bedded sandstone facies correspond to seasonal channel sand, deposited respectively as flooded channel facies and downcurrent-migrating transverse-to-linguoid bars of braided streams. Fine clastic facies occurring as capping on conglomerate and sandy bars correspond to periods of minimal discharge in protected or abandoned parts of outwash plains. Frequent lateral shifts of braided channel bars in outwash plains may account for the recurrence of fining-upward cycles. The deposition of outwash debris is attributed to meltwater streams following southward retreat of the Talchir ice lobe. The ice lobe, perhaps, developed locally on the highlands of Parasnath hill to the south, but there is also a possibility that it represents the northern limit of the ice lobes that advanced northward across the Damodar Valley Basin.Read More
Publication Year: 1982
Publication Date: 1982-01-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 15
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