This issue of Palaeogeography Palaeoclimatology Palaeoecology is devoted to papers on the Permian– Triassic boundary crisis and Early Triassic biotic recovery. It is an outgrowth of the Symposium on Early Triassic Chronostratigraphy and Biotic Recovery that was held in Chaohu, China, on May 21st–23rd, 2005 under the auspices of IGCP Project 467 and attended by about 200 Earth scientists with a ...

The low enthalpy program developped in the Paris Basin provides the opportunity for studying the gas geochemistry of the calcareous aquifer of the Dogger. Hydrocarbons and C02 are mainly biogenic, He displays high concentrations. He, Ar and N2 have multiple origins (radioactive decay, atmospheric migration, biochemical processes). The distribution of the gases in the zones of the basin varies i...

—Stromatolite shapes, sizes, and spacings are products of microbial processes and interactions with topography, sedimentation, and flow. Laboratory experiments and studies of modern microbial mats and sediments can help reconstruct processes that shaped some typical stromatolite forms and some atypical microbially influenced sediments from Neoproterozoic cap carbonates. Studies of modern, cohes...