四川渡口地区晚第四纪沉积物的孢粉分析及其地质意义

作者在四川渡口地区选择了桐子林、金江火车站、盐边新村三个露头剖面,做了系统的孢粉取样及分析。本文就分析结果,讨论了本区第四纪地层的划分、对比及古环境等方面问题。

THE SPORO-POLLEN ANALYSIS OF LATE QUATERNARY DEPOSITS FROM DUKOU REGION, SICHUAN PROVINCE, AND ITS GEOLOGICAL SIGNIFICANCE

Using the sporo-pollen analysis the geological ages of Quaternary loose deposits from the Dukou region and their paleoenvironment are studied and a lot of plants rich in sporo-pollen from the sections of Tongzilin,Jinjiang railway station,and Yanbian Xincun are discovered. Among the woody plants Pinus,Abies,and Picea are predominant over Betula,Qucrcus,Ulmus. Among the herbs Chenopodiaceae,Artemisia,Compositae and Gramineae are predominant. Among the fern Polypodiaceae and Hymenophyllum are predominant. On the basis of the mentioned sporo-pollen combinations it can be inferred that the dominating vegetation developed at that time in the studied areas was aiphyllium needle leaved forest,reflecting a 7.5℃-9℃ colder climate in Quaternary than today.The results of sporo-pollen analysis are comparable with the sporo-pollen data on the late Late-Pleistocene sediments in many regions of our country. Moreover,the seven samples from these sections for G¹⁴ dating give an age value of ca. 15000-25000 yrs. For this reason the three sections under study can be ascribed to the Late Pleistocene.