Mineral magnetic characterization of the Godavari river and western Bay of Bengal sediments: Implications to source to sink relations

Autor: Satish J. Sangode, D. C. Meshram, N. Suresh, Y. R. Kulkarni, Jan Bloemendal
Rok vydání: 2015
Předmět:
Zdroj: Journal of the Geological Society of India. 85:71-78
ISSN: 0974-6889
0016-7622
Popis: Godavari Drainage Basin (GDB) represents the largest Peninsular source of sediment flux into the Bay of Bengal. Mineral magnetic measurements are carried out on the GDB sediments along with the surface sediment cores from the adjoining western Bay of Bengal to explore the relationship between the two. The sediments from Godavari river transact shows varied floodplain to bed load composition with the former dominated by unimodal soft ferrimagnetic, Deccan basalt source. Whereas, the bed load show polymodal composition of mixed nature dominated by silici-clastic sediments derived from the Precambrian granites and Proterozoic sequences. The surface sediment cores (~100-300 cm) from the Bengal fan region off the Godavari delta broadly display an increasing trend in ferrimagnetic mineralogy towards top. Based on mineral magnetism the ferri- and para-magnetic susceptibilities are assigned to the basaltic and siliciclastic sources, respectively which also represents the low and high rain fall zones. The increasing upwards trend of the ferrimagnetic minerals in the western Bay of Bengal sediments, therefore, can be related to the predominance of basaltic source over the siliciclastic/cratonic source from the GDB. These controls of magnetic susceptibility in the Bengal fan sediments are assigned to the fluctuation of the two sources as a result of differential weathering in response to monsoonal variability.
Databáze: OpenAIRE
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