Abstract The Lower Son Valley is generally overlooked despite a lengthy history of archaeological and geological studies in the adjacent Middle Son Valley. However, recent explorations in the former have yielded a large number of Palaeolithic and microlithic sites. This paper provides an initial report on Doma, a newly discovered site with the first-known stratified bifaces in this part of the valley. The site preserves multi-period technologies in different contexts, including terminal Acheulean/early Middle Palaeolithic and Upper Palaeolithic (all tentatively assigned based on respective typologies). Preliminary field observations are presented on the sedimentary sequence, archaeological surveys, topographical mapping, raw material and the overall palaeoanthropological assessment of Doma. The raw material utilized at the site is primarily porcellanite, derived from exposures of the Semri Group of the Vindhyan Supergroup. The oldest Palaeolithic evidence at Doma broadly resembles Late Acheulean sites dated to c. 140–120 ka in the nearby Middle Son Valley. The Pleistocene sediments here also yielded mammalian fossil specimens, such as long bone fragments, dental specimens and antler fragments. Along with the lithics and fossils, the site also preserves datable sedimentary sequences with calcrete, all key proxies in developing a testable model of technological transitions within a palaeoenvironmental framework, in the future.

Abstract Indian basement faults, which bound three orogen-perpendicular palaeotopographic ridges of Precambrian Indian basement south of the Himalaya, extend to the base of the Indian lithosphere and to the northern extent of the Indian lithosphere underneath Tibet. In the eastern Himalaya, the active orogen-perpendicular Yadong–Gulu graben is aligned with an earthquake-generating strike-slip fault in the high Himalaya. We argue that the graben results from crustal necking during reactivation of the underplated basement fault. In the central Himalaya, along-strike diachronous deformation and metamorphism within the Himalayan metamorphic core, as well as lateral ramps in the foreland thrust belt, spatially correspond to the Lucknow and Pokhara lineaments that bound the subsurface Faizabad Ridge in the Indian basement. Analogue centrifuge modelling confirms that offset along such deep-seated basement faults can affect the location, orientation and type of structures developed at various stages of orogenesis and suggests that it is mechanically feasible for strain to propagate through a melt-weakened mid-crust. We suggest that inherited Indian basement faults affect the ramp-flat geometry of the basal Main Himalayan Thrust, partition the Himalayan range into distinct zones, localize east–west extension resulting in the Tibetan graben and, ultimately, contribute to lateral variability in tectonic evolution along the orogen's strike.