黄土高原黄土、红色粘土与古湖盆沉积物关系

Depositional Ralation between the Loess, Red Clay and Sedimtation of the Lakebasin in the Loess Plateau

本文通过磁性地层学、古生物地层学、沉积学的对比研究，讨论了中国黄土高原地区黄土，红色粘土与该区重要古湖盆之一，古三门湖堆积物之间关系，并分析气候环境对它们的影响。主要结论如下：１）红色粘土与上覆黄土可以是连续沉积，并呈相渐变关系。２）中国黄土与三门组记录了布容正极性带与松山负极性带。Ｂ／Ｍ界限位于Ｌ８，Ｊ亚带位于标志层Ｌ９与Ｌ１５之间，大约Ｓ１０－Ｓ１３之间，Ｏ亚带位于Ｓ２２－Ｓ３３，或三门组之中。Ｍ／Ｇａ界限对应于黄土与红土界限。并基本对应于三门组与游河组界限。３）红色粘土（三趾马红粘土）并非仅仅是中新世保德期沉积物。它包括上新统与中新统，上新世静乐组记录了高斯正极性带，吉尔伯特负极性带，中新世蓝田组记录了Ｅｐｏｃｈ５。４）古三门湖堆积包括早更新世早期三门组（１．２０—２．５０Ｍａ，松山负极性带），上新世晚期游河组（２．５０—３．５０Ｍａ，高斯正极性带），更早期的三门湖沉积未出露。三门组与午域黄土为同期异相沉积，记录了松山负极性带，游河组则与该区上部红色粘土（静乐组上段）为同期异相沉积。

This paper discusses the relation of sedimentation between the loess, red clay and deposits of the Sanmen lake in the Chinese loess highland by studies of magnetostratigraph, biostratigraph, sedimentology and environmental analysis. Main results are 1)the Early Pleistocene loess overlies continuously on the top of the Neogene red clay in some sections. 2)the Brunhes normal polarity zone and Matsuyama reversal polarity zone were recorded in the loess section and the deposit of the Sanmen lake . The B/M boundary is located in the L 8 loess layer. The J subzone is located between the S 10 S 13 loess beds. The O subzone is located in S 22 S 33 loess beds, or in the deposit of the Sanmen lake. The M/Ga boundary corresponds to the loess/red clay boundary, and also basically to the Sanmen group/Youhe group boundary. 3)the red clay includes not only the sediment of Miocene Baode epoch, but also the deposits of Pliocene and Miocene. The Pliocene Jingle group recorded the Gauss normal polarity zone and the Gilbert reversel polarity zone, but the Miocene Lantian group recorded Epoch 5. 4)the deposit of the Sanmen lake includes the Early Pleistocene Sanmen group (1.20 2.45Ma, Matsuyama reversel polarity zone) and the Late Pliocene Youhe group (2.50 3.50Ma, Gauss mormal polarity zone). The Sanmen group and Wuyu loess are the contemporaneous different facies deposits, the Matsuyama reversal polarity zone was recorded in them. The Youhe group and the upper red clay(upper of Jingle) are the contemporaneous different facies deposits as well, which recorded the Gauss normal polarity zone.