RAPID DEFORESTATION ACROSS THE PERMIAN-TRIASSIC BOUNDARY IN SOUTH CHINA

Modern tropical rainforests are the haven for millions of plants and animals. The terrestrial alluvial and marine/non-marine transitional seamarsh-littoral Permian-Triassic boundary sequences in Southwest China record a rapid climatic drought and deforestation of the tropical Gigantopteris flora which is synchronous with the mass extinction of marine organisms. Associated with the die-off of the tropical rainforest and the mass extinction of marine organisms are sharp negative carbon-isotope shift slightly below the Permian-Triassic boundary, charcoal-rich layers due to widespread wildfires, and frequent volcanic eruptions. Considering these data, the Permian-Triassic ecologic crisis is regarded to be triggered by the effects of severe changes in atmospheric chemistry including greenhouse conditions derived from excessive CO₂ increase and substantial atmospheric S-containing acid input to ecosystems both in the sea and on the land. These changes are likely caused by volcanism, resulting in widespread acidification indicated by higher contents of pyrite in marine sequences and malachite in terrestrial sequences across the Permian-Triassic boundary.