中国科学院南京地质古生物研究所机构知识库

Two distinct palynofloral provinces have been recognized for the Early Cretaceous of western China, including Xizang (Tibet): one indicated by the presence of the cheirolepidiacean pollen grain Dicheiropollis and the other by abundant representatives of different gymnospermous pollen, especially Araucariacites and Callialasporites. The boundary between them coincides with the Yarlung Zangbo Suture. To the north of the suture, the Xizang-Tarim Dicheiropollis Province occupies a wide region from southern Xinjiang through the central and northern Qinghai-Xizang Plateau to the west of Yunnan. South of the suture, the Southern Xizang Araucariacites-Callialasporites Province appears to have affinities with the South Gondwanan (floral) Realm. Despite some similarities with the composition of assemblages from other palynofloral provinces, both are distinct and considered to reflect different climates. Hot arid to semi-arid conditions are indicated by the Dicheiropollis Province, whereas a more humid and somewhat cooler climate is suggested for the Araucariacites-Callialasporites Province.