摘要
本文综合了兰州地区三个典型剖面的古地磁年代,同时参考岩石特征及古气候变化,确定兰州地区黄土年代的划分。即午城(组)黄土(Q_1),绝对年龄73～209万年;离石(组)黄土(Q_2),绝对年龄9～73万年,马兰(组)黄土(Q_3),绝对年龄0.8～9万年和三家山(组)黄土(Q_4),绝对年龄0.8万年。 通过具有代表性的皋兰山剖面的孢粉组合特征的分析,确定兰州地区第四纪以干旱——半干旱草原气候为主的基本规律。
On synthesizing the paleomagnetic times of three typical sections inLanzhou area, rock characteristics, and paleoclimatic changes, the authorsdetermined the division of loess time. They are: Wucheng loess (Q1), theabsolute age from 2090000 to 730000 aB. P; Lishi loess(Q2), from 730000to 90000 aB. P; Malan loess(Q3), from 90000 to 8000aB, P; and Sanjiashanloess(Q4), 8000 years. Having analysed the representative sporc-pollen combining characterist-ics in Gaolan Mountains section, this paper also concluded that arid andsemiarid prairie climate was the basic law and chief trend since theQuaternary period of this region. And there were two periods of warm-wet climate during that time.
出处
《兰州大学学报（自然科学版）》
CAS
CSCD
北大核心
1991年第3期131-138,共8页
Journal of Lanzhou University(Natural Sciences)
关键词
古地磁年代
古气候
兰州地区
the paleomagnetic times
typical sections
rock characteristics
paleoclimate changes
sporo-pollen combining characteristics
semiarid prairie climate
