论文部分内容阅读
腾格里沙漠南缘土门剖面末次冰消期层段由3层沙丘砂、2层湖相沉积、2层古土壤和5层黄土构成。主元素氧化物中,SiO_2含量在沙丘砂层呈现峰态,而在黄土、湖相沉积及古土壤呈现谷态;Al_2O_3、TFe(Fe2O3+FeO)、CaO、MgO、Na_2O、K_2O和TiO_2则在沙丘砂层呈现为谷,在黄土、湖相沉积及古土壤中呈现为峰,SiO_2分别与Al_2O_3等氧化物在垂直方向上呈镜像对称。结合研究区地形,对元素氧化物特征分析后,认为可用硅铝比高低变化指示本区东亚冬夏季风变化。划分出了9个冷暖波动事件,按时间先后依次为:C5(14930~14847 a BP)、W4(14847~13810 a BP)、C4(13810~13620 a BP)、W3(13620~13340 a BP)、C3(13340~13010 a BP)、W2(13010~12650 a BP)、C2(12650~12050 a BP)、W1(12050~11860 a BP)和C1(11860~11600 a BP)。本研究层段与格陵兰GRIP冰芯及南京葫芦洞石笋记录的末次冰消期冷暖变化有较高的相似性,可能本区末次冰消期季风气候变化受北半球高纬驱动。
On the southern margin of the Tengger Desert, the last ice depletion stage of the Tumen section is composed of 3 layers of sand dunes, 2 lacustrine facies deposits, 2 layers of paleosol and 5 layers of loess. In the oxide of main element, the content of SiO_2 showed a kurtosis in the dune sand layer, while the sediments in the loess and lacustrine facies and the ancient soil presented the grain state; while Al 2 O 3, TFe (Fe 2 O 3 + FeO), CaO, MgO, Na 2 O, K 2 O and TiO 2 Sand dunes appear as valleys, which show peaks in loess, lacustrine sediments and paleosol. SiO 2 is mirrored vertically with Al 2 O 3 and other oxides. Combined with the topography of the study area, after analyzing the characteristics of elemental oxides, it is considered that the change of East Asian winter monsoon can be indicated by the change of Si / Al ratio. Nine events of cold and warm were classified as follows: C5 (14930-14847 a BP), W4 (14847-13810 a BP), C4 (13810-13620 a BP), W3 (13620-13340 a BP) , C3 (13340-13010 a BP), W2 (13010-12650 a BP), C2 (12650-12050 a BP), W1 (12050-11860 a BP) and C1 (11860-11600 a BP). The research interval has a high similarity with the GRIP ice core in Greenland and the stalagmite record of the last year in Qinghai Province. It is possible that the monsoon climate change in the last ice-cooling period of this region is driven by high latitudes in the northern hemisphere.