甘肃酒泉盆地新民堡群植物群特征及其古生态意义

Characteristics of the Xinminbao Group Flora in Jiuquan Basin,Gansu Province, and Its Paleoecological Significance

对甘肃酒泉盆地新民堡群赤金堡组、下沟组和中沟组植物大化石进行研究,并结合前人对该盆地植物化石的研究资料,共统计植物化石25属46种,其中赤金堡组7属9种,下沟组7属7种,中沟组14属32种.在植物化石埋藏类型研究的基础上,重建了甘肃酒泉早白垩世古植被群落,并划分为近岸湿地群落、山间低地—缓坡群落、山间高地群落、旱生群落4个群落.根据植物类群之间的比例关系、植物群的整体特征和特征分子,推断甘肃酒泉早白垩世古气候由温暖潮湿的亚热带气候向炎热干旱转变的趋势. Athrotaxites、Pseudofrenelopsis、Brachyphyllum、Equisetum植物化石的存在,表明甘肃酒泉早白垩世气候环境存在季节性变化.

Fossil plants collected from the Lower Cretaceous Chijinpu Formation, Xiagou Formation and Zhonggou Formation of the Xinminbao Group in Jiuquan Basin were studied, combined with previous data, the results show that the flora of the Xinminbao Group is composed of 46 species in 25 genera of fossil plants, including the flora of the Chijinpu Group is composed of 9 species in 7 genera, the flora of the Xiagou Group is composed of 7 species in 7 genera, the flora of the Zhonggou Group is composed of 32 species in 14 genera.Based on the burial type analysis of plant fossils, this study reconstructed the ancient flora group of the Jiuquan flora. Four plant communities have been recognized in ascending order as follows: riparian hydrophyte community, lowland-slow-slope community,intermountain upland community, and xerophyte community. Based on the proportion of taxa in flora, the overall characteristics of flora, the characteristic molecules, we can infer that the paleoclimate of Jiuquan, Gansu province changed from warm and humid subtropical climate to hot and arid climate during the Eraly Cretaceous. The presence of Athrotaxites, Pseudofrenelopsis, Brachyphyllum, Equisetum fossils shows that the climate in Jiuquan of Gansu had a seasonal variation during the Eraly Cretaceous.