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HIMALAYAN JOURNAL OF SCIENCES | VOL. 5 | ISSUE 7 (SPECIAL ISSUE) | 2008 24 Sediments of the Himalayan peripheral foreland basin, developed due to progressive thrust-loading (DeCelles and Giles 1996, Dickinson 1974) and subsequent exhumation/upliftment of the mountain chain, records signature of hinterland tectonics visa-vis basin filling processes. The synchroneity of the foreland sediments with widespread early Oligocene glaciation suggests that hypothesis of tectonics-climate connection, whereby the cooling was driven by drop in atmospheric CO2 via enhanced silicate weathering of the rising Himalayan orogen (Raymo and Ruddiman 1992, Pagani et al. 2005), has considerable merit. As a test-case Paleogene Sub-Himalayan foreland sediments of marine Subathu and continental Dagshai formation rocks were studied to identify the teleconnection between tectonics and climate, if any. The Subathu-Dagshai transition here is marked by the presence of a ~31 Ma old (Najman et al. 2004) characteristic quartz rich mature sandstone locally termed as the “White Sandstone”. It marks the termination of marine Subathu Formation and initiation of continental molasses Dagshai Formation and represents an important evolutionary stage in the geodynamic history of the foreland basin (DeCelles and Giles 1996, Sinclair 1997). However, the status of White Sandstone has always been uncertain varying between marine Subathu (a beach or tidal flat; Singh and Khanna 1980, Srivastava and Casshyap 1983) to fluvial Dagshai (Najman et al. 2000, 2004). Further, raging debates exist about the possible continuity/discontinuity between Subathu and Dagshai formations (see Bera et al. 2008 and references therein). Since the White Sandstone plays a crucial role in this debate the present study focused on process based sedimentology of this unit. Detailed bed form geometry and sedimentary structure shows that the White Sandstone unit is made up of three distinct components viz., Lower shoreface (between fair weather wave base and storm wave base), Upper shoreface (above fair weather wave base) and Foreshore/beach. Lower shoreface deposits are characterized by intercalation of centimeter thick fine sand and shale couplets, although definite signature of hummocky cross stratified (HCS) unit is not recorded in the present study. These units lie between two erosional surfaces. The lower erosional surface is sharp and it places the units directly over the offshore/ shelf sediments. Presence of gutter cast and rip-up clast at the base of these units suggest the lower erosional surface must be a storm weather wave base or regressive surface of marine erosion (RSME) (Plint 1988). The upper erosional surface is marked by the truncation of the fine sand shale intercalation of lower shoreface with decimeter thick lenticular unit of upper shoreface and dips towards the basinal depocenter. The presence of this surface above basal RSME allowed us to interpret it as a fair White Sandstone in Subathu Sub-Basin: an example of tectonically driven forced regressive wedge