IMPLICATION OF COAL-FORMING PALAEOCLIMATE OF GIGANTOPTERID PLANTS IN THE NORTH CHINA PLATE

Based on the variability of genus taxon, three different regions in the plate are well recognized as follow: Ⅰ-rare gigantopterid region, Ⅱ-Gigantonoclea region and Ⅲ-concurrented Gigantonoclea-Giganto pteris region. The evidence furnished by the geographical limitation of genus taxon and foliar physiognomy feature of this plant group appearantly indicates that a changed trend northwestwardly from an unseasonal rain tropical forest climate in Ⅲ region into savanna climate in Ⅱ region and steppe climate in Ⅰ region is continuesely transformed. The present emplacement direction of the Permian palaeoclimatic zones in the North China Plate suggests that it underwent a northward movement from low to middle latitude in north Hemisphere, accompaneied with a conterclockwise retation of about 35°-45°. The main part of the plate was away from the rain tropical forest climate zone, which is favorable to form coal, into the savanna and steppe climate zones to be difficut to forming coal. In this way, the late Early/early Late Permian coal resourse is contracted to the southeastern coner of the North China Plateform.