河西走廊黑河、梨园河河流阶地对新构造运动的响应

发布时间：2018-05-16 10:42

本文选题：黑河 + 梨园河　；参考：《中国地质大学(北京)》2017年硕士论文

【摘要】：本文研究区位于青藏高原东北部榆木山地区,新生代构造活动强烈。研究该地区的阶地发育和变形特征及阶地的年代序列,可以为新构造运动活动期次和整个榆木山的隆升过程的提供依据。本文通过在野外对河西走廊黑河、梨园河河流各级阶地剖面、河拔高程、河谷横剖面进行详细的测量、描述,对光释光测年样品进行采集,进行微地貌测量等一系列工作,以及在室内对数据进行整理分析,得出以下结论:研究区内黑河阶地发育级数最高为六级,梨园河最高发育5级阶地,说明该地区至少有6次不同程度的抬升。河流阶地发育较全,阶地面较平坦,多数为耕作区。光释光测年及区域对比得到黑河各级阶地形成时代分别为,T1年龄为5.54±0.61ka,T2年龄为12.7±0.9ka,T3年龄为19.69±1.32ka,T4年龄为47.0±3.4ka,T5年龄为54.7±4.6ka,T6形成于中更新世晚期。根据阶地位相图得到黑河在上龙王庙段构造隆升强烈,测得T3、T4分别被错断2.564m和5.913m。黑河口第三级阶地逆冲速率为1.0mm/a,第四级阶地逆冲速率为1.25mm/a,从晚更新世中期至晚更新世晚期,T4的逆冲速率为0.12mm/a,反映黑河晚更新世构造活动性比较强烈。研究区共经历五次新构造运动:榆木山经历了渐新世的缓慢抬升,在中新世晚期约在3.58Ma青藏高原东北缘开始最近一次构造隆升,榆木山也开始隆升,北祁连山开始快速隆升和酒泉前陆盆地逐渐形成。早更新世以来,由于老断裂复活,构造运动明显增强,使山体抬升,上新统变形、倾斜明显;盆地相应下沉,快速堆积形成磨拉石建造,即沉积玉门组.中更新世,河流开始下切形成阶地,肃南红湾寺附近梨园河T5、黑河口T6形成。强烈的构造运动使玉门组变形,同时盆地内部酒泉组开始沉积。晚更新世以来,盆地内沉积各河流阶地砂砾石层,酒泉组发生微倾斜.在黑河口附近可见受断层影响奥陶纪的灰绿色安山质凝灰岩、千枚状板岩逆冲到晚更新世砾石层及黄土层之,反映黑河晚更新世构造活动性比较强烈。全新世中期—至今,平原河流下切,发育低级阶地,主要是黑河及梨园河的T1和T2阶地。
[Abstract]:The study area is located in the elm mountain area in the northeast of the Qinghai Tibet Plateau, and the Cenozoic tectonic activity is strong. The study of the characteristics of terrace development and deformation and the chronological sequence of terrace in this area can provide the basis for the uplift process of the new tectonic movement period and the entire elm mountain. This paper passes through the field of the Hexi Corridor Heihe, Liyuan River The terrace profiles at all levels, the elevation of the river and the cross section of the river valley are measured in detail, the samples are collected, the microgeomorphological measurements are carried out, and the data are arranged in the laboratory. The following conclusions are drawn: the highest development progression of Heihe terrace in the study area is six, and the highest development of the terrace in the Liyuan river is 5 level terrace. It shows that there are at least 6 different levels of uplift in this area. The river terrace is well developed and the terrace surface is flat, most of which are cultivated. The age of light release and light release and regional comparison of terrace in Heihe are respectively, T1 age is 5.54 + 0.61ka, T2 age is 12.7 + 0.9ka, T3 age is 19.69 + 1.32ka, T4 age is 47 + 3.4ka, and T5 age is 54.7 4.6ka and T6 are formed in the late Middle Pleistocene. According to the order status phase diagram, the tectonic uplift of Heihe in the upper Longwang Temple section is strong, and T3 is measured. The thrusting rate of third stage terrace in 2.564m and 5.913m. black estuary is 1.0mm/a, and the thrusting rate of grade fourth is 1.25mm/a. From the middle late Miocene to late Pleistocene, the thrusting rate of T4 is in the late Pleistocene. 0.12mm/a, reflecting the relatively strong tectonic activity of the late Pleistocene in Heihe. The study area has experienced five neotectonic movements: the elm mountain experienced the slow uplift of the Oligocene, the latest tectonic uplift began in the late Miocene epoch on the northeastern edge of the 3.58Ma Qinghai Tibet Plateau, the elm mountain began to rise, and the northern Qilian Mountains began to rapidly uplift and the Jiuquan foreland basin. Since the early Pleistocene, since the early Pleistocene, due to the resurrection of the old fault, the tectonic movement was obviously enhanced, the mountain body was raised, the upper Neocene was deformed and the tilt was obvious; the basin correspondingly subsiding, and the sedimentary Yumen formation was formed quickly, that is, the sedimentary Yumen formation. The Middle Pleistocene, the river began to cut down the terrace, the Liyuan River T5 near the Sunan Red Bay temple and the black mouth T6 formed. The strong tectonic movement made the Yumen formation deformed, and the Jiuquan formation in the basin began to deposit. Since the late Pleistocene, the sand and gravel layers of each river terrace were deposited in the basin, and the Jiuquan formation was slightly inclined. It reflects the strong tectonic activity of late Pleistocene in Heihe. In the middle period of the Holocene, the plain rivers cut down and developed low-grade terraces, mainly the T1 and T2 terraces of the Heihe and Liyuan rivers.

【学位授予单位】：中国地质大学(北京)
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：P542

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