包头地区晚第四纪沉积地层与环境演化

Stratigraphy and environmental evolution of late Quaternary in Baotou area,Inner Mongolia,China

对包头地区BT1-1孔沉积岩芯进行了系统的岩性、地层年龄和沉积相的分析。结果表明:该钻孔剖面揭露了中更新世末期(130ka BP)以来的沉积地层,可划分为3个地层段:全新统(Qh):0-16.9m,为河流相沉积,底部年龄为11.9ka B.P.;上更新统(Qp3):16.9-84.2m,为一套河湖相交替沉积,底部年龄为118.5ka B.P.;中更新统顶部(Qp22未见底):84.2-101.1m,为湖相沉积,底部年龄为130.6ka B.P.。包头地区晚第四纪沉积环境经历了从湖泊环境-河湖交替环境-以河流环境为主的演化过程。128.2-126.4ka B.P.期间,由于气候寒冷干旱、湖盆萎缩而形成的盐湖沉积(芒硝层)是该区湖相沉积的一个标志层。

According to the systematic analysis of lithology,chronology and sedimentary facies of Baotou BT1-1 hole section,it is showed that the section presents the strata since 130 ka B. P.,which can be divided into 3sections. Holocene series（ Qh） is a set of fluvial facies strata,that formed at 11. 9ka B. P.. Upper Pleistocene series（ Qp32）,is a set of alternating deposition between rivers and lakes,that formed at 118. 5ka B. P.. The top of the Middle Pleistocene series（ Qp2^2） is a set of Lacustrine sediments,that formed at 130. 6ka B. P.. The sedimentary environment of Baotou during the late Quaternary had gone through deep lakes during the last stage of Middle Pleistocene- alternating environment between rivers and lakes during Late Pleistocene-- river environment mainly during Holocene. The Glauber＇s salt layer formed at the climate of cold and arid between 128. 2- 126. 4ka B. P. is a marker bed of the lacustrine sediments in this area.