High resolution luminescence dating of the Khovaling Loess Plateau sites (Tajikistan)

We have studied the loess-palaeosol sequences of the Khovaling Loess Plateau in Tajikistan, which form the most complete record of subaerial sedimentation in Central Asia. Studied sections contain several layers with Early and Middle Palaeolithic tools, and therefore record some of the earliest events of hominin dispersal into Central Asia.

As part of a major NordForsk funded project ‘Timing and Ecology of the Human Occupation in Central Asia’ (THOCA; www.thoca.org), we applied high-resolution luminescence dating to the upper parts of three sections of Khovaling loess plateau (Khonako-II, Kuldara, and Obi-Mazar) in order to: (1) provide an independent timescale for palaeoclimatic studies; (2) assess the completeness of the sedimentary record; and (3) investigate the main stages of dust accumulation over this interval.

The luminescence chronology extends back to ~250 ka and reveals distinct erosional hiatuses ranging in duration from ~7 ka to a full glacial-interglacial cycle (~100 ka). Some of these breaks were not identifiable in the field. These discontinuities had not been previously recognized, potentially leading to significant errors in palaeosol identification and, consequently, in the presumed chronology. Now, we have a better understanding of the aeolian sedimentation in the region and the stages of loess/palaeosol formation. The new chronology provides a reliable correlation of regional features with global events and relates them to climate change, soil cover development, and the evolution of Early and Middle Paleolithic.