甘肃陇西盆地黄土的孢粉研究

黄土是温带干旱气候条件下的风成沉积物, 它反映了一定的古气侯和古地理环境。我国黄土高原是世界最发育的典型黄土, 通过抱粉分析手段来研究黄土地层形成过程的气候演变, 已是当代地质学者重视的问题之一。1980年笔者对陇西盆地黄土部面进行了孢粉分析, 现就古植物、古气候和地层划分等问题进行如下讨论。     

LOESS IN THE LONGXI BASIN OF GANSU PROVINCE

The Nuanquangou loess section in the Longxi Basin has been examined in terms of stratigraphic investigation,. including 14C dating, paleomagnetic polarity, spore-pollen diagram, and mineral and chemical analyses. The results indicate that the section is one of the ancient loess sections with a continuous sedimentation and composed of homogeneous materials with abundant carbonate. The Brunhes / Matuyama boundary and the Jaramillo event were recorded in the section. Stratigraphically,this section can be divided into the Holocene and the Pleistocene loess. The latter includes Malan, Lishi and Wucheng loess in descending order. They were developed at about 1.2 Ma ago, whereas the Nuanquangou loess section possesses some local characteristics different from those observed in other areas.     

甘肃陇西盆地的黄土

陇西盆地黄土的研究系于1978年配合工程任务开展的,重点研究了文峰镇东南暖泉沟剖面,分析项目有古地磁、C~(14)年龄,孢子花粉、重矿物,粘土矿物、化学成分等。本文系对该剖面所做各项分析的总结。工作中得到甘肃省物资局和省地质局所属部门的大力协助和支持,谨致谢意。