{delta}13C depth profiles from paleosols across the Permian-Triassic boundary: Evidence for methane release

摘要

Stable carbon isotopic analyses of organic carbon (13C) in individual paleosol profiles from Permian–Triassic sequences of Antarctica reveal systematic isotopic variations with profile depth. These variations are in many cases analogous to those in modern soils, which are functions of redox conditions, soil development, and degree and type of microbial decay. In modern soils, these isotopic depth functions develop independently from vegetation changes (C₃ versus C₄ vegetation) and can be diagnostic of soil orders. This study shows that soil-intrinsic functions can be preserved in the 13C values of paleosols as old as 260 Ma and constitute valuable data for paleoecological interpretations.