Editorial

Paleosols are traditionally regarded as good records of paleoecological and paleoclimaticchanges thus are widely used to indicate paleoclimatic conditions and land surface evolution. Theywere never regarded as a precise tools for paleoclimatic change. This view changed withimplementation of the IGBP core project: PAGES (Past Global Change) in mid-1980. Thesuccessful correlation of long-term continuous oxygen isotope climatic records of deep seasediments with Quaternary paleosol-loess sequences in Europe by Kukla and in China by LiuTungsheng further validated usefulness of paleosols for paleoclimatic and surface evolutionstudies. The continuous Chinese paleosol-loess sequences provided insights into past

Recent research results showed that the Cathaysia flora originated and developed from the global uniform Lepidodendropsis flora of the Early Carboniferous, which had already become an independent flora in the early Late Carboniferous (Namurian B to C). The center of origin of the Cathaysia flora is restricted to the North China Plate. On the basis of the successional characteristics of the Cathaysia flora in different geological ages, it may be divided into seven evolutionary stages. The evolutionary trend of the Cathaysia flora, as a whole, was characterized by the gradual increase of the typical Cathaysian elements in the sequence from the early Late Carboniferous to the early Late Permian, which began to decline during the late Late Permian. The climatic differentiation, tectonic movement, oceanic circulation, palaeogeographical environment, extraterrestrial event and plant evolution caused the mass extinction of the Cathaysia flora on a large scale by the end of the Permian.