SIMULTANEOUS PERMO-TRIASSIC BOUNDARY MARINE AND TERRESTRIAL MASS EXTINCTIONS: THE GLOBAL FUNGAL SPIKE DISCOVERED IN THE KAROO SUPERGROUP (SOUTH AFRICA)

The mass extinction that terminated the Paleozoic Era eliminated more than 90% of marine species; in the terrestrial realm, vertebrates lost an estimated 70% of families and plants, 90% or more of the species. The cause of this excessive mortality at the Permian-Triassic boundary, the greatest in geologic history, is enigmatic, in part because of the correlation difficulties among Late Permian strata. Most marine faunal correlations have been hampered by acute endemism, except for the more recently developed conodont biostratigraphy, which has begun to provide a basis for correlation in the marine realm. Magnetostratigraphy, commonly a correlation tool in such circumstances, also does not do a very good job. Most Late Permian sequences are composed of shallow marine strata, a depositional setting that does not lend itself to the preservation of the primary magnetization, largely because of magnetic mineral dissolution in the reducing environment produced by copious biologic activity and/or the tendency towards diagenetic recrystallization. However, a new, unambiguous Permian-Triassic boundary marker has surfaced. An abundance of fungal remains has been shown to be present globally at the boundary in sequences that have been examined for palynomorphs. Both marine and terrestrial sections record this phenomenon. This “fungal spike” appears to indicate a sudden global catastrophic devastation of land plants at this time. Most recently, a thin stratigraphic interval of abundant fungal remains has been discovered in the Karoo Basin of South Africa, strata which contain the world’s best record of Permian-Triassic (P/Tr) vertebrate evolution. Contained within a meter of strata, the fungal spike pinpoints the P/Tr boundary in this prolific vertebrate record. This discovery now permits the precise temporal correlation between terrestrial and marine faunal mass extinctions, and supports a scenario of global catastrophe at the end of the Permian.