OSL re-dating and paleoclimate of Laoya Cave in Guizhou Province, southwest China

Abstract

Laoya Cave is a significant prehistoric human site in Guizhou Province, Southwest China, and optically stimulated luminescence (OSL) and a Bayesian depositional model were used to update the chronology of the cave. Six OSL samples were dated to 16.7 ± 1.2, 18.0 ± 1.1, 28.8 ± 2.3, 32.1 ± 2.8, 57.7 ± 6.5, and 74.0 ± 5.9 ka, respectively, and the Bayesian deposition model has provided a coherent chronological framework, revealing boundaries with median ages of 18.5, 25.0, 27.5, 28.6, 29.9, and 74.4 ka for Boundaries 1/2, 2/3, 3/4, 4/5, 5/6, and 6/9, respectively. By comparing the new chronological framework with the related records of paleoclimate and human activities, we gain insight into the relationship between the environment and Paleolithic hominins at different times. During relatively warmer periods, humans tend to spread, while in relative colder climates, they tend to rely more heavily on caves and employ hunting strategies with an equal age distribution. These survival strategies help humans prevent the threats of cold weather. Additionally, the analysis of OSL dating results uncovers a discrepancy between OSL and accelerator mass spectrometry radiocarbon (AMS ¹⁴C) dating methods, with AMS ¹⁴C dates generally appearing older at later ages (<∼30 ka). This phenomenon may be due to disturbances caused by human activity, and OSL dating may recognize this to some extent.