黄土高原0.8 Ma以来地面抬升的时空特征研究
作者简介:胡春生(1979-),男,安徽无为人,讲师,主要研究方向为资源与环境。E-mail:huchsh03@163.com
收稿日期: 2011-12-12
要求修回日期: 2012-05-10
网络出版日期: 2012-09-20
基金资助
安徽省自然地理学重点学科科研团队项目(asdgl0903)、国家自然科学基金(40471016)资助
The Spatial and Temporal Features of Surface Uplift in Loess Plateau Since 0.8 Ma
Received date: 2011-12-12
Request revised date: 2012-05-10
Online published: 2012-09-20
Copyright
胡春生 , 潘保田 , 苏怀 . 黄土高原0.8 Ma以来地面抬升的时空特征研究[J]. 地理科学, 2012 , 32(9) : 1131 -1135 . DOI: 10.13249/j.cnki.sgs.2012.09.1131
The river terrace is one of the direct geomorphic evidences of the surface uplift. By analyzing the characteristics of the Yellow River terraces in Loess Plateau, it is presented that the terraces are mainly tectonic genesis, and formed after the Yellow River reached a quasi-equilibrium state. It is reasonable to use the Yellow River terraces for representing the surface uplift of the Loess Plateau. In the Lanzhou Basin, two fourth terraces of the Yellow River are selected as the study sections, namely the Zaoshugou terrace and the Wuyishan terrace. At the Zaoshugou terrace, the altitude of gravel stratum is 80 m higher than the river level. The top of the gravel stratum is overlain by at least 64 m eolian loess, and the paleosol S8 is at the bottom of the eolian loess. At the Wuyishan terrace, the altitude of gravel stratum is 140 m higher than the river level. The top of the gravel stratum is overlain by at least 100 m eolian loess, and the paleosol S8 is at the bottom of the eolian loess. The optically stimulated luminescence (OSL) dating result indicates that the age of the upper part of paleosol S1 at the Zaoshugou terrace is 70.4±7.6 ka. The results of paleomagnetic dating, optically stimulated luminescence dating and loess-paleosol sequence matching indicate that the two terraces have the same age, and both were formed at about 0.865Ma. Therefore this paper advances that there is the Yellow River terraces at 0.8Ma in the Lanzhou Basin, and the fourth terrace of the Yellow River may be a geomorphic response to the event of the surface uplift at 0.8Ma around the Qinghai-Tibetan Plateau. According to the research on the Yellow River terraces at 0.8Ma in the Loess Plateau and the correlative literature, this paper verifies that there was a large-scale surface uplift at about 0.8Ma in the Loess Plateau, and the surface uplift resulted in river incision and terrace formation. Lanzhou, Heishan Canyon, Shanxi-Shaanxi Canyon and Sanmenxia were also selected as the typical research areas in the Loess Plateau,and obvious spatial and temporal features of the surface uplift of the Loess Plateau since 0.8Ma was discovered, basing on the characteristic analysis of the sequences of the Yellow River terraces at this four sites. The rates of surface uplift are calculated by the rates of river incision and the amounts of surface uplift are calculated by the depth of river incision (height above river). The spatial feature is that the surface uplift of the western Loess Plateau is more intense than that of the eastern Loess Plateau, and the temporal feature is that the uplift speeds up gradually, especially since the late Pleistocene. This paper also proposes that the surface uplift of the Loess Plateau since 0.8 Ma is related to the surface uplift of the Qinghai-Xizang Plateau.
Key words: Loess Plateau; river terrace; 0.8 Ma; surface uplift; spatial and temporal features
Fig.1 Loess Plateau and the middle reaches of Yellow River图1 黄土高原和黄河中游 |
Fig.2 The loess sections and the measure results of paleomagnetismon of Zaoshugou section and Wuyishan section图2 枣树沟阶地和五一山阶地黄土剖面及古地磁测年结果(1. 黄土; 2. 古土壤; 3. 河漫滩粉砂; 4. 砾石层) |
Table 1 The terraces of Huanghe River at 0.8 Ma in Loess Plateau表1 黄土高原地区黄河0.8 Ma阶地统计表 |
地点 | 阶地序 | 拔河高度(m) | 年代 (Ma) | 定年方法 | 数据来源 |
---|---|---|---|---|---|
兰州 | T4 | 80~140 | 0.865 | 古地磁 | 自测 |
黑山峡 | T9 | 140 | 0.742 | 钙膜 | [18] |
河曲 | T3 | 100 | 0.787 | 古地磁 | [19] |
吴堡 | T5 | 130 | 0.787 | 古土壤 | |
吴堡 | T5 | 109 | 0.85 | 古土壤 | [1] |
禹门口 | T5 | 127 | 0.85 | ||
韩城 | T5 | 74 | 0.85 | ||
三门峡 | T4 | 70 | 0.865 | 古地磁 | [20] |
三门峡 | T4 | 50 | 0.86 | 古地磁 | [21] |
Table 2 The sequences of Huanghe River terraces at four sites in Loess Plateau since 0.8 Ma表2 黄土高原4个地区0.8 Ma以来黄河阶地发育序列 |
地点 | 阶地序 | 拔河(m) | 年代(Ma) | 定年方法 | 数据来源 |
---|---|---|---|---|---|
兰州段 | T4 | 140 | 0.865 | 古地磁 | 自测 |
T3 | 70 | 0.141 | TL | [7] | |
T2 | 25 | 0.05 | 14C | ||
T1 | 10 | 0.01 | 14C | ||
黑山峡段 | T9 | 140 | 0.742 | 钙膜 | [18] |
T8 | 120 | 0.495 | 钙膜 | ||
T7 | 95 | 0.36 | 钙膜 | ||
T6 | 85 | 0.285 | 钙膜 | ||
T5 | 80 | 0.215 | 钙膜 | ||
T4 | 73 | 0.139 | 钙膜 | ||
T3 | 55 | 0.094 | 钙膜 | ||
T2 | 30 | 0.018 | 钙膜 | ||
T1 | 13 | 0.005 | 14C | [22] | |
晋陕峡谷段 | T3 | 100 | 0.787 | 古地磁 | [19] |
T2 | 60 | 0.336 | 古土壤 | ||
T1 | 10 | 0.06 | TL | ||
T5 | 130 | 0.787 | 古地磁 | ||
T4 | 110 | 0.412 | 古土壤 | ||
T3 | 70 | 0.245 | 古土壤 | ||
T2 | 30 | 0.129 | 古土壤 | ||
T1 | 10 | 0.06 | TL | ||
三门峡段 | T4 | 70 | 0.865 | 古地磁 | [20] |
T3 | 30 | 0.625 | 古地磁 | [19] | |
T2 | 12 | 0.129 | TL | [21] | |
T1 | 5 | 0.06 | TL |
Table 3 The amounts of surface uplift at four sites in Loess Plateau since 0.8 Ma (m)表3 黄土高原4个地区0.8 Ma以来的地面抬升量 (m) |
地点 | 兰州段 | 黑山峡段 | 晋陕峡谷段 | 三门峡段 | |
---|---|---|---|---|---|
河曲–吴堡 | 吴堡–韩城 | ||||
抬升量 | 80~140 | 140 | 100~130 | 74~127 | 50~70 |
Fig.3 The rates of surface uplift at four sites in Loess Plateau since 0.8 Ma图3 黄土高原4个地区0.8 Ma以来的地面抬升速率 |
The authors have declared that no competing interests exist.
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