Palaeoenvironmental dynamics and Palaeolithic occupation at Katoati, Thar Desert, India

Abstract

Late Pleistocene palaeoenvironments in the Thar Desert (India), located at the eastern extent of the Saharo-Arabian desert belt, have fluctuated considerably as a result of the varying range and intensity of the Indian summer monsoon. Phases of widespread Pleistocene aridity are well documented in the Thar Desert, but research focusing on humid proxies is critical to examine how the region may have facilitated population expansions across southern Asia. At Katoati, located on the northeast margin of the Thar Desert, the combination of field recording of sediment sections with detailed analyses (micromorphology, stable isotope, loss on ignition, magnetic susceptibility, and X-ray fluorescence) from an archaeological site identify a series of hominin occupations during phases of enhanced humidity between ~96 and 60 ka. A gradient of humidity on the eastern margin of the Thar Desert during the late Pleistocene is identified, with the periodic humidity evident at Katoati occurring more frequently and with longer duration towards the southern margin. This uneven distribution of humidity in the Thar Desert is likely to have strongly influenced when and where hominin populations could expand into and across the region.

Environments and Cultural Change in the Indian Subcontinent

“…Large proportions of the main assemblagesdating to 95.6 5 13.1 ka (LD-1149), 96-77 ka, 77 ka (LD-1090), and~60 ka-are composed of highly cortical simple cores and flakes. This probably represents a focus on primary reduction activities, exploiting the availability of cobbles made up of diverse materials associated with uplifted deposits from the Jayal Gravel ridge (Blinkhorn et al 2017). Based on raw material types, only a single artefact can be identified as exotic to the site.…”

A transect of environmental variability across South Asia and its influence on Late Pleistocene human innovation and occupation

“…Located at the margins of monsoonal precipitation, the Thar Desert would have been particularly sensitive to changes in monsoonal intensity, leading it to fluctuate between an arid barrier and humid gateway for human dispersals into South Asia (e.g. Field et al ., ; Petraglia et al ., ; Groucutt and Blinkhorn, ; Blinkhorn et al ., ). During peaks of monsoonal intensity, the Thar Desert would have been more attractive for human occupation than at present, whereas a suppressed monsoon (notably the case during MIS 4 and MIS 2 – Rendell, ) appears to have rendered the region too arid to sustain human populations (Figs and 5).…”

“…a; Blinkhorn et al , ). A range of palaeoenvironmental evidence from Katoati indicates the occupations occurred during phases of enhanced humidity, with isotopic evidence indicating strong summer rainfall and a dominance of C 4 grass (Blinkhorn et al ., ).…”

“…The last interglacial, MIS 5, is associated with a consistent gradient of humidity, starting with evidence for limited fluvial activity in the north‐east Thar (e.g. Katoati), to the larger Luni River draining the central regions, and ending with extensive fluvial action in the Orsang, Sabarmati and Mahi Valleys at the southern margins of the desert (Juyal et al , , ; Jain et al , ; Blinkhorn et al , ). Limited aeolian activity during MIS 5 may indicate brief periods of increased aridity, but dune formation appears to be followed by substantial periods of landscape stability and intensive pedogenesis of dune deposits (Singhvi et al , ).…”

“…From the start of MIS 3, a resumption of monsoonal activity is evident in aeolian and colluvial sediment units, indicating increased precipitation and enhanced wind activity in the north‐east and central desert (Andrews et al , ; Blinkhorn et al , ). Fluvial and aeolian aggradation events are followed by a phase of relative landscape stability between 50 and 35 000 cal a BP (Chawla et al , ; Juyal et al , , ; Jain et al , ).…”