Thermoluminescence in response to the mass extinction event in Penglaitan Section in Laibin, Guangxi

Abstract

Thermoluminescence (TL) in marine carbonate has been proposed as a potential proxy for reconstruction of paleoceanography history, and has already been used in defining the Quaternary environment. However, its availability in the geological time scale, such as Permian, is still on debate. The mass extinction event caused by drastic changes of global marine environment in Middle-Late Permian provides a typical example to testify the applicability of this proxy. Here we measured the natural thermoluminescence of the carbonate-dominating marine sediments collected from the strata through the Guadalupian-Lopingian mass extinction boundary (G/LB) in the Penglaitan Section in Laibin, Guangxi, China. Our results reveal that TL intensities of carbonate are much higher than those of siliceous rocks, which indicates that the carbonate is the main contributor to the TL. The variation of TL intensities are related with Mn and Fe contents in the carbonate lattices while high Mn and low Fe (e.g., high Mn/Fe ratio) in carbonate will release stronger TL. Due to the better storage of carbonate lattices for original information of Mn and Fe in seawater, thermoluminescence of carbonate-dominating sediments/rocks could sensitively reflect marine environment and biological productivity in geological time scale.