Abundance anomalies of aromatic biomarkers in the Permian-Triassic boundary section at Meishan, China - Evidence of end-Permian terrestrial ecosystem collapse

Several aromatic biomarkers detected in solvent extracts and kerogen pyrolysates from samples of the Global Stratotype Section and Point (GSSP) for the Permian-Triassic boundary at Meishan, China, show distinctive relative-abundance anomalies that may be related to the end-Permian biotic crisis on land. Enrichment of dibenzofuran homologues across the Permian-Triassic boundary may corroborate the concept of excessive soil erosion following loss of rooted vegetation. Enrichment of alkylphenol entities occurs just below the main marine mass extinction horizon and prior to the characteristic end-Permian delta C-13 decline. The alkylphenols were probably derived from lignin and may provide a molecular record of dieback of woody vegetation. Highly decreased relative abundances of dibenzothiophenes could be indicative of excessive supply of Fe2+. It is suggested that Fe2+ was land-derived and may have originated from soils. In addition to the Permian-Triassic boundary interval, biomarker abundance anomalies also occur around the Wuchiapingian-Changhsingian boundary in the basal part of the Meishan section. (C) 2007 Elsevier B.V. All rights reserved.