Middle Paleolithic Assemblages from the Indian Subcontinent Before and After the Toba Super-Eruption

Abstract

The Youngest Toba Tuff (YTT) eruption, which occurred in Indonesia 74,000 years ago, is one of Earth's largest known volcanic events. The effect of the YTT eruption on existing populations of humans, and accordingly on the course of human evolution, is debated. Here we associate the YTT with archaeological assemblages at Jwalapuram, in the Jurreru River valley of southern India. Broad continuity of Middle Paleolithic technology across the YTT event suggests that hominins persisted regionally across this major eruptive event.

Population increase and environmental deterioration correspond with microlithic innovations in South Asia ca. 35,000 years ago

“…The lower levels of the open-air localities contain a distinct chronostratigraphic marker in the form of a volcanic ash (tephra) layer deposited from the Sumatran Toba supereruption at ca. 74 ka (5). The sequence following the ash-fall returned a series of optically stimulated luminescence (OSL) and radiocarbon ages ranging from immediately post-Toba to the terminal Pleistocene.…”

“…This evidence is thought to reflect a Late Pleistocene population expansion in the subcontinent that is unparalleled elsewhere. In addition, both archaeological and genetic models postulate South Asia as a key region on the proposed southern route for Out-of-Africa dispersals (2)(3)(4)(5). Despite the importance of the region, however, archaeological data from South Asia rarely feature in discussions of human evolution, and little attempt has been made to bring South Asia's archaeological record to bear on discussions of its unique population dynamics.…”

Genetic and archaeological perspectives on the initial modern human colonization of southern Asia

“…2), where a series of stone tool assemblages have been recovered from locations both underlying and overlying thick deposits of Toba ash-fall deposits, with a series of associated optically stimulated luminescence (OSL) dates ranging from ∼77 to ∼38 ka (1-6) (Archaeology). Technologically, all of these assemblages are of characteristically Middle Paleolithic form [attributed by the excavators to a generalized "Indian Middle Paleolithic tradition" (1)], broadly similar to those documented across a wide region of both Europe and western Asia over a similar span of time (18). The claim that these industries provide evidence for an early arrival of modern humans from Africa before 74 ka rests crucially on analyses of two small samples of residual "core" forms recovered from below the Toba ash-fall deposits (at Jwalapuram sites 3 and 22), compared with those from a broadly contemporaneous range of Middle Paleolithic/Middle Stone Age (MSA) sites in other regions of Eurasia and Africa (1,4,6).…”

“…2). The second, more recently proposed view, is that there was a much earlier dispersal of modern humans from Africa sometime before 74 ka (and conceivably as early as 120-130 ka), reaching southern Asia before the time of the volcanic "supereruption" of Mount Toba in Sumatra (the largest volcanic eruption of the past 2 million y) at ∼74 ka (1)(2)(3)(4)(5)(6).…”

“…Issues surrounding the initial modern human colonization of the geographically pivotal region of southern Asia have generated intense controversy in the recent genetic and archaeological literature (1)(2)(3)(4)(5)(6)(7)(8)(9)(10)(11)(12)(13).…”