globalchange  > 气候变化事实与影响
CSCD记录号: CSCD:6511640
论文题名:
浑善达克沙地最老砂层的年龄
其他题名: The age of the oldest aeolian sand in the Otindag sandland
作者: 孙晓巍; 周亚利; 张岳敏; 炊郁达
刊名: 科学通报
ISSN: 0023-074X
出版年: 2019
卷: 64, 期:17, 页码:870-880
语种: 中文
中文关键词: 浑善达克沙地 ; 光释光测年 ; 火山熔岩 ; 风沙活动
英文关键词: Otindag sandland ; OSL dating ; volcanic lava ; aeolian activity
WOS学科分类: AUTOMATION CONTROL SYSTEMS
WOS研究方向: Automation & Control Systems
中文摘要: 浑善达克沙地位于东亚季风的边缘地带,是研究气候演变的理想区域.沙地内分布的火山熔岩覆盖在古砂层之上,使得较老的砂层由于顶盖岩层保护作用而得以保存.以往对浑善达克沙地的气候变化过程的研究主要集中于末次盛冰期以来时段,缺乏更长时间尺度的气候变化记录,其主要原因是缺乏合适的地质载体和相对应的长尺度年代数据.本文通过对砂质古土壤、风成砂、湖相砂和火山烘烤层等样品进行光释光测年,利用常规SAR法、TT-OSL法和pIRIR(200,290)法分别对石英和长石进行等效剂量的测定,并进行了不同测年矿物及方法的对比,确定最终的沉积年龄,获得了截至目前最老的风成砂年龄为321.2 ka.建立了沉积物年代框架,重建了浑善达克沙地中更新世晚期以来的演化过程:距今320, 160.3~151.6和4.4 ka时,风沙物质快速堆积,沙丘活化,沙地扩张;距今5.0, 2.4和1.3 ka时,风沙活动规模小,沙丘固定;距今320.4 ka左右浑善达克沙地内已经是沙丘与湖泊共存的地貌景观.
英文摘要: The Otindag sandland, located at the boundary of the East Asian monsoon area, is sensitive to climate change and is therefore an ideal place to investigate past environmental evolution. Due to frequent volcanic eruptions that have occurred since the Cenozoic, numerous interbeds of multi-stage basalt and sand exist in the stratigraphic sequence, which allowed older sand to be preserved due to the protective effect of the overlying rock. Previous studies of climate change in the sandland mainly focused on the time interval since the last glacial period, and information is lacking regarding climate change over longer timescales and younger volcanic activity. The key reason for this is that suitable geological carriers are rare, which prevents the expansion of the desired sediment chronological scale. In order to establish the chronological framework, samples of the sandy paleosoil, aeolian sand, lacustrine sand and volcanic baked layer were collected and dated by the optically stimulated luminescence (OSL) method. The conventional SAR, TT-OSL and pIRIR(200,290) procedures were used to obtain equivalent doses of quartz and feldspar. To ensure the accuracy of the dating data, the age of the feldspar dating of the oldest aeolian sand sample (TBB) was compared with the quartz result, and the quartz and feldspar ages were found to be consistent with each other within the error range. Considering the error of the age measured by TTOSL (384.268.0 ka) exceeded 10%, the age measured by the pIRIR(200,290) method (321.211.5 ka) was adopted to represent the deposition age of the aeolian sand sample. In addition, the age of the oldest sand deposition in the three sections of the Otindag sandland may reach 300 ka, mainly due to the different thermal history and provenance from other areas such as Loess Plateau, resulting in the different saturation dose and dose rate lever of quartz or feldspar. The sedimentary age framework established by OSL dating enabled the reconstruction of the evolution process of the Otindag Sandland. The climate was cold and dry during the periods corresponding to 321.2, 160.3-151.6 and 4.4 ka, and the aeolian sand material quickly accumulated during these times, as dunes were activated and the sandland expanded. During the periods corresponding to 5.0 ka and 2.4-1.3 ka, sandy soil developed efficiently, implying the dunes were fixed. The oldest lacustrian sand age is 320.416.0 ka for quartz dated by the SAR method. Hence, aeolian sand and lacustrine sand developed in the same period, which indicates that there was a landscape where dunes and lakes coexisted around 320.4 ka, such as at present. The Optical Stimulated Luminescence dating results of the volcanic baking layer and the underlying coarse sand layer confirm that volcanic activity occurred around 321.2 and 155.0 ka. Combined with results of previous research, this study indicates that the northeast and northwestward basement faults of the northern margin of the North China Craton and the Central Asian orogenic belt are characterized by extensional tectonic properties in the background setting of plate subduction, and relative uplift and settlement occur in the sandland formation zone.
资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/155879
Appears in Collections:气候变化事实与影响

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作者单位: 陕西师范大学地理科学与旅游学院, 西安, 陕西 710062, 中国

Recommended Citation:
孙晓巍,周亚利,张岳敏,等. 浑善达克沙地最老砂层的年龄[J]. 科学通报,2019-01-01,64(17):870-880
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