Human presence in the southeastern Tibetan Plateau after the Last Glacial Maximum

Abstract

The Tibetan Plateau (TP) is a critical region for understanding patterns of human occupation due to its hostile environment. Numerous archaeological sites have been reported on the plateau, except in its southeastern part. This study presents new archaeological findings from the Congqiancuo area in southeastern Tibet, located in the Haizishan Mountain region, a glacial landscape. Lithic artifacts, including small-sized flake tools and microblades, were discovered on the surface and in a test pit within the low terrace of Congqiancuo Lake, a moraine-dammed lake. Excavation revealed a 1.3-m stratigraphy with four layers, with artifacts found in Layers 3 and 2. Luminescence dating of quartz and K-feldspar grains, along with radiocarbon dating of charcoal, provided age estimates. The luminescence dating results were consistent across quartz and K-feldspar grains, while radiocarbon ages on charcoal were anomalously young. Bayesian statistical modeling refined the luminescence ages, yielding a date of 17.7 ± 1.9 ka for Layer 4, indicating human occupation shortly after the glaciers receded at 18.1 ± 1.4 ka. Cultural layers (Layers 3 and 2) were deposited between 13.8 and 4.2 ka, with the earliest human presence suggested around 11.8 ka. Sediment analysis of grain size and magnetic susceptibility reveals that humans likely inhabited the lake shore during a warmer climate, highlighting southeastern Tibet as a crucial settlement area post-Last Glacial Maximum and a potential route for the spread of microblade technology in high-altitude regions.