OSL Chronology of the Siling Co Paleolithic Site in Central Tibetan Plateau

Lan Luo,Lupeng Yu,Chang Huang,Wenhao Zheng,Yantian Xu,Hua Tu,Zhongping Lai

doi:10.3389/feart.2021.699693

Abstract

When and how was the Tibetan Plateau (TP), one of the least habitable regions on Earth, occupied by humans are important questions in the research of human evolution. Among tens of Paleolithic archaeological sites discovered over the past decades, only five are considered coeval with or older than the Last Glacial Maximum (LGM, ∼27–19 ka). As one of them, the Siling Co site in the central TP was previously announced to be ∼40–30 ka based on radiocarbon dating and stratigraphic correlation. Given the loose chronological constraint in previous studies, we here re-examined the chronology of the Siling Co site with the optically stimulated luminescence (OSL) dating technique. Four sections from the paleo-shoreline at an elevation of ∼4,600 m in southeastern Siling Co were investigated, with stone artifacts found from the ground surface. Dating results of nine samples delineated the age of ∼4,600 m paleo-shoreline to be ∼10–7 ka (∼8.54 ± 0.21 ka in average). This age indicates that the Siling Co site is not earlier than the early Holocene, much younger than the former age. The revised age of the Siling Co site is consistent with the wet and humid climate conditions on the TP during the early Holocene.

Highlights

With an average elevation of ∼4,000 m, a mean annual temperature close to the freezing point of water, and only half the concentration of oxygen at the sea level, the Tibetan Plateau (TP) offers one of the most demanding and hostile living conditions to humans
We focus on the Siling Co (“Co” means “lake” in Tibetan) site whose age was only loosely constrained by stratigraphic correlation with 14C-dated lacustrine terraces (Yuan et al, 2007)
Most of the optically stimulated luminescence (OSL) signals decreased to a level undistinguishable from the background within the first second of stimulation, indicating the dominance of the fast component, which is preferable for OSL dating (Figure 4D)

Summary

Introduction

With an average elevation of ∼4,000 m, a mean annual temperature close to the freezing point of water, and only half the concentration of oxygen at the sea level, the Tibetan Plateau (TP) offers one of the most demanding and hostile living conditions to humans For this reason, the timing and mechanism of human colonization of this region as well as the accompanying cultural and physiological responses to numerous environmental extremes are of high concern and heatedly debated (Zhang and Li, 2002; Madsen et al, 2006; Zhao et al, 2009; Brantingham et al, 2010; Simonson et al, 2010; Yi et al, 2010; Chen et al, 2015; Meyer et al, 2017; Zhang et al, 2018; Chen et al, 2019; Zhang et al, 2020).

Results

Discussion

Conclusion