ABSTRACT

Ancient microliths in South Asia have now been dated at least as early as 42-25 thousand years ago (ka), specifically at Mahadebbera and Kana, situated in the West Bengal area of India. This information adds substantively to scientific understanding of early human migrations and significant technological developments during the Pleistocene. Dating was possible through Optically Stimulated Luminescence (OSL) and the associated microliths and other artifacts were examined in detail. In relation to prior findings in the larger surrounding region, the new discoveries allow discussion of raw materials acquisition, possible travel routes, and other issues during a critical time of human evolutionary history. KEYWORDS: microliths, Late Pleistocene, South Asia, hominid migration, Optically Stimulated Luminescence (OSL).

NEW EVIDENCE HAS EXPANDED KNOWLEDGE OF AN ANCIENT MICROLITHIC TECHNOLOGY in South Asia within the range of 42-25 thousand years ago (ka). This work has contributed significantly to clarifying the origins of the microlithic technology and possible relations with larger issues of the development of modern human behaviors and the migration routes of Homo sapiens during the Late Pleistocene. Specifically, new investigations have supported dating through Optically Stimulated Luminescence (OSL), in concert with detailed documentation of microlithic assemblages at the sites of Mahadebbera and Kana, located in the West Bengal area of India (Figs. 1, 2).

Microlithic technologies have been linked confidently with complex human behavior in South Asia during the Pleistocene, specifically referring to microblades or non-geometric and geometric tools made on blade blanks during contexts prior to 12 ka (Bar-Yosef and Kuhn 1999; Clarkson et al. 2009; James and Petraglia 2005; Mellars 2006). Evidence supporting the antiquity of microlithic industries and the "complete cultural package" (James and Petraglia 2005:S3) associated with it has been emerging from South Asia over the last few years (Clarkson et al. 2009; Lewis et al. 2014; Mishra et al. 2013; Roberts et al. 2015). The dating has now been pushed back to 45 ka at sites such as Metakheri in Madhya Pradesh in Central India (Mishra et al. 2013; cf. Groucutt et al. 2015). Considerable diversity has been noticed in the technology through time, as at Jwalapuram (Clarkson et al. 2009), and also between sites, as when comparing findings at Metakheri (Mishra et al. 2013) with Jwalapuram (Clarkson et al. 2009).

The dating of microliths in South Asia has been much debated. There has also been controversy concerning how the dated assemblages may have reflected ancient human behaviors and migration patterns during the Pleistocene (Dennell and Petraglia 2012; Groucutt et al. 2015; Mellars et al. 2013; Petraglia et al. 2010). Central to the debate has been the appearance of an older Middle Palaeolithic technology apparently followed by the later microlithic technology of our present focus, which has been documented from different archaeological sites and regions (Blinkhorn et al. 2015; Boivin et al. 2013; Clarkson et al. 2009). Two perspectives prevail on when Homo sapiens entered South Asia: it may have occurred around 55--50 ka in association with coastal migration, or it may go back even earlier, to around...