新疆拜城早白垩世孢粉植物群及其环境意义

Palynoflora and its environmental significance of the Early Cretaceous in Baicheng,Xinjiang Autonomous Region

基于新疆拜城地区下白垩统舒善河组发现的29属48种孢子花粉化石的研究,建立了研究区早白垩世早期孢粉植物群。舒善河组孢粉植物群以松杉目掌鳞杉科的优势和真蕨目海金沙科的繁茂为特征。根据孢粉植物群的特征,探讨了该区早白垩世早期古生态、古气候和古地理特征。掌鳞杉科植物是耐干旱和耐热的乔木和灌木,当时掌鳞杉科和海金沙科植物在亚热带气候下都很常见,表明拜城地区早白垩世早期古气候属于亚热带干燥型,气候炎热干旱。孢粉植物群的生物多样性和植物地理分布明显的分带性显示该区早白垩世早期古地理具有复杂多样的景观,包括山峦、山谷、山涧、河流三角洲沼泽和沼泽湿地等。

Based on the investigation of 48 species of spores and pollen belonging to 29 genera found in the Lower Cretaceous Shushanhe Formation in the Baicheng district of the Xinjiang Autonomous Region, the early Early Cretaceous palynoflora in the area has been established. The palynoflora of the Shushanhe Formation is characterized by the dominance of Cheirolepidiaceae of Coniferales and the influence of Lygo- diaceae of Filicales. In accordance with the characters of the palynoflora, the early Early Cretaceous palaeoecological, palaeoclimatic and palaeogeographic characters have been discussed. Because the Chei- rolepidiaceous plants were drought resistant and thermophilic trees and shrubs, and both the Cheirolepidi- aceae and Lygodiaceae were most common in subtropical climates in that period, the palynoflora indicated a dry and rather hot climate. Judging from the palynological data, the early Early Cretaceous palaeocli-mate in the Baicheng district should belong to the arid type of subtropical zone. The biodiversity of the palynoflora and the obvious zonality of the plant geographic distribution show that the early Early Cretaceous palaeogeography in the area should possess complex and various landscapes, including multi-peaked mountains, mountain valleys, mountain streams, river delta marsh and marsh wetland etc.