PROGRESS IN THE RESEARCH ON COAL BALLS IN CHINA

摘要

Since the first discovery of coal balls in Permian strata at Shuicheng Guizhou Province, in 1972, coal balls have been found, in many sites. The stratigraphic position of coal balls in most sites belongs to the Upper or Lower Permian, but in Jingyuan, Gansu Province, coal balls belongs to the Carboniferous (Namur C). It has been known that coal balls distribute very wide in China. The occurrence in stratigraphic horizon of Chinese coal balls is not very equal with the Euramericans. For the understanding of how the Paleozoic plants developed, evoluted in the late Palaeozoic, the geologic time of the coal balls in China just link with the Eurammericans'. In the last 20 years, new approaches of the research on coal balls have been gained which mainly exhibit in the following parts.