Sr–Nd isotope composition of the Bay of Bengal sediments: Impact of climate on erosion in the Himalaya

Copyright © 2011 by The Geochemical Society of Japan. roughly the same since the Miocene (Bouquillon et al., 1990; France-Lanord et al., 1993). The sources are dominated by contributions from the Higher Himalaya (HH) with subordinate supply from the Lesser Himalaya (LH). However, on millennial timescale, there are evidences of variations in the provenance of sediments related to climatic changes (Colin et al., 1999; Goodbred, 2003; Ahmad et al., 2005; Bookhagen et al., 2005, 2006; Kessarkar et al., 2005; Clift et al., 2008; Rahaman et al., 2009). This is consistent with the important role that climate has on the present-day erosion over the Himalaya, with most of sediments delivered to the BoB by rivers during the southwest monsoon (Islam et al., 1999; Goodbred, 2003). In contrast, some of the studies carried out in the Nepal Himalaya (Burbank et al., 2003), have decoupled climate and erosion and have highlighted the important control of tectonics on erosion. Compared to the Himalaya, there has been paucity of information on the paleo-erosion pattern of the Peninsular India river basins and their controlling factors. Based on clay mineralogy and Sr–Nd isotopes of marine sediments from the south-west margin of India, Kessarkar et al. (2003) concluded that these sediments are mainly from the Peninsular India and the Himalaya (Indus basin) and that their provenance and transport pathways remained the same during the late Pleistocene and Holocene. These limited information on the monsoon-erosion relation in the Himalaya and the Peninsular India regions, warrant a detailed study. The western Bengal fan receives Sr–Nd isotope composition of the Bay of Bengal sediments: Impact of climate on erosion in the Himalaya