Quaternary International 159 (2007) 93–101 Late Pleistocene fluvial sedimentary facies, the Dhadhar River basin, Western India Rachna Raj Department of Geology, Faculty of Science, M. S. University of Baroda, Vadodara – 390 002, India Available online 20 October 2006 Abstract The Late Pleistocene fluvial succession is exposed as 18–20 m high incised vertical cliffs all along the Dhadhar River basin in western India. The major fluvial sedimentary facies of the Late Pleistocene deposits in the Dhadhar River basin have preserved evidence of palaeodrainage and could provide an important link between the sub-humid Narmada basin in the south and the semi-arid Mahi basin in the north. The sedimentary facies documented include overbank fines, which are associated with crevasse splays. Fine grained overbank sediments are interpreted as having formed by sheet flow of sediments over the banks of minor distributary channels during the flood stage. The overlying thinly stratified fluvial sands and silts, at the top of the exposed sediment succession show a thin cap of aeolian sediments suggesting less intense aeolian activity than that observed in Sabarmati, Mahi and Orsang basins, though a significant reduction in fluvial activity is suggested during the arid phase of the LGM. However, the river may still have been perennial assuming that it retained the larger part of the catchment. r 2006 Elsevier Ltd and INQUA. All rights reserved. 1. Introduction Stratigraphical, geomorphological and chronological studies in the Gujarat alluvial plains have been useful in addressing palaeoenvironmental and tectonic changes (Chamyal et al., 1997; Maurya et al., 2000; Juyal et al., 2000; Chamyal et al., 2002, 2003). The fluvial history of some of the important basins of the Gujarat alluvial plains is now known (Merh and Chamyal, 1997; Maurya et al., 2000; Juyal et al., 2000; Chamyal et al., 2002, 2003; Juyal et al., 2004; Bhandari et al., 2005). Dhadhar is an independent river of the Gujarat alluvial plains, flowing between two major rivers, the Mahi River in the north and the Narmada River in the south (Fig. 1). Geomorphologically, the Dhadhar River basin can be divided into four zones: the upland zone, the pediment zone, the alluvial zone, and the estuarine zone (Fig. 2). The upland zone shows fault-controlled drainage and entrench- ment in the hard basement rocks, and the uplifted fluvial terraces suggest active tectonism in the area (Rachna Raj, 2004). The pediment is characterized by a thin succession of Quaternary deposits resting on the basement rocks, and the alluvial zone is the main basin fill marked by the thick succession of the Quaternary deposits. Dhadhar and its tributaries show deep incision of the order of 18–20 m in this zone (Rachna Raj, 2004). Previous research (Rachna Raj, 2004) has established that during Late Pleistocene, the Orsang River was an independent river flowing through the present day course of Dhadhar River. The course of the Orsang River changed during the Early Holocene due to tectonic uplift along the major faults in the area, turning southwards to join the Narmada River (Figs. 2(A), (B)). The Late Pleistocene sediment records of the Dhadhar and Orsang Rivers are similar and correlatable. Tectonism, sealevel and climatic changes during Holocene contributed significantly in the evolution of the present day Dhadhar and Orsang basins (Rachna Raj, 2004). As an independent basin, the Dhadhar River basin is very important from the point of view of palaeoenviron- mental studies. The climate of this basin is influenced by the SW monsoon. Late Quaternary environmental changes have, however, remained uninvestigated in the Dhadhar River basin, which could have otherwise provided an important link between the sub-humid Narmada basin in the south and the semi-arid Mahi basin in the north. The Late Pleistocene fluvial succession of the Dhadhar River ARTICLE IN PRESS 1040-6182/$ - see front matter r 2006 Elsevier Ltd and INQUA. All rights reserved. doi:10.1016/j.quaint.2006.08.014 E-mail address: naveenrachna@gmail.com.