摘要
根据河西走廊大面积水文地质勘察工作获得的钻探资料和测试成果,以及近几年来从事第四纪地层研究工作取得的大量成果,依据岩石地层学、年代地层学和生物地层学,结合地貌特征,对该区全新世地层划分和古地理环境问题探讨如下:
Hexi Corridor is situated ia the western part of Gansu province, which belongs to the inland drainage basin There is Qilian?shan on the south part, Beishan on the North part, and the Corridor is between them. The Quaternary Strata of Hexi Corridor develops well, The extent of Holocene series olistributes widely, in which the Variation of the lithological Character and Litho-facies is big, its genetical types are many, Its outcrop condition of the stratotype section is good, There are plenty of fossils, The sporo-pollens are more, The sedimentary rhythm is clear and the strata are perfect.According to a huge amount of the typical geological section and the 14C dating data, and by means of the trisection method, The Holocane Series may be divided into three parts: Namely lower Holocene Series ( 7000-12000years ago), The middle Holocene Series ( 2500-7000years ago ) and the upper Holocene Series ( less than 2500years ago ) .Accordig to the position of the stratotype section outcrop, litho-logical character, lithofacies variatiou of Holocene series, the gene-tical characteristic, The geographycal distribution, the fossil age as well as the 14C dating data, The Holocene Series may be simu-lantly established into 9 groups: Namely, The upper Holocene Series may be subdivided into Yanchi group and Fuchenggou group, The middle Holocene Series may be subdiviede into Ganzhou group and pochengzi Group and The lower Holocene Series may be subdivided into pingzhuan group, Bulongji group, Xia Shuyin group, Maocheng group and Baitujin group. According to the sporo-pollen analysis, The Holocene Epoch climate is the alternate variation between cold and warm, which may be generally divided into three Cycles of early, middle and late period, During every cycle period, The arid cycle and wet cycle interchange each other. The period interval is the difference in long term and short term, in which the lesser cycle is included by the major cycle. The general law of the Holocene Epoch climate shows a tendency to the arid development, whi
出处
《甘肃地质》
1989年第10期1-19,共19页
Gansu Geology
