Permian wood from inner Mongolia, north China: with special reference to Palaeozoic climate change of north China block

Abstract

Three species or gymnosperm woods are discovered from the upper Shihhotse Formation of Inner Mongolia. North China. of which two are described as new. i.e., Araucarioxylon neimongense sp. nov. and Araucarioxylon wudense sp. nov., because of their high percentage of partly biseriate xylem rays. In accordance with Pant and Singh's (1987) suggestion on the taxonomy and classification of araucaroid fossil wood, the Palaeozoic gymnosperm fossil woods of araucaroid type in Cathaysian nora are re-evaluated. They are recombined within Protophyllocladoxylon, Araucarioxylon, Zalesskioxylon, Chapmanoxylon and Cordaioxylon. The presence or absence of growth rings and their vertical distribution pattern were closely related to the change or the palaeoclimatic condition resulted from the drifting of the North China Block rrom the tropical zone to the middle-high latitude zone throughout the late Palaeozoic.