干旱区生态环境知识资源中心(Arid): 格尔木河小干沟坡积沉积特征与古环境重建

Arid

	格尔木河小干沟坡积沉积特征与古环境重建
其他题名	Sedimental features and paleo-environment reconstruction of the slope deposit at Xiaogangou of the Golmud River
	张梅; 陈艺鑫; 银森录; 张敬春; 李川川; 刘耕年
来源期刊	干旱区地理
ISSN	1000-6060
出版年	2011
卷号	34 期号:6 页码:890-903
中文摘要	格尔木河小干沟坡积剖面的地质地貌环境、宏观沉积构造、石英砂SEM结构特征及年代学研究揭示出该区坡积的沉积特征和坡地环境演化过程。格尔木河流域普遍存在坡积上覆风尘堆积，下部坡积代表坡面片流过程盛行，反映较湿润的气候环境，上部风尘堆积则代表风沙过程盛行，反映较干旱多风的气候。小干沟坡积物石英砂SEM结构特征组合不同于其它沉积环境，具有自己典型的特征组合，反映了青藏高原干剥蚀环境下石英砂特有表面结构特征组合。石英砂SEM结构特征中出现许多高起伏的颗粒外形，普遍出现次棱角、次棱脊、贝壳状断口、平行解理、溶蚀坑与溶蚀缝、硅质球、硅质鳞片、SiO_2结晶特征。石英砂表面结构特征的颗粒频率曲线揭示坡积物成因以风化作用和化学作用为主，无冰川作用。颗粒外形特征表明坡积物为近源堆积；机械特征主要由强烈的风化作用及搬运过程中的碰撞造成；其中强烈的化学作用特征与该地区具有碱性、冷暖变化及局部良好供水的环境条件以及后期稳定沉积环境有关。小干沟剖面揭示出末次冰期以来经历冷湿(30-17 ka)到暖干（14 ka~至今）的环境变化过程。与格尔木河上游小南川剖面比较，不同的岩性、地貌、水热条件导致坡积沉积特征的差异，反映地貌过程垂直地带性。
英文摘要	The sedimentary features and environment evolution process of Xiao Gangou slope profile of the Golmud River would be revealed by the study on the geological and geomorphic, environments, macroscopic sedimentary structures, SEM microtextures of quartz grains and chronological constraints. Slope deposits covered with eolian deposits are common in this area. Slope deposit at the bottom represents sheet flow prevailing, indicating the climate of humidification. However, the eolian deposit on the top shows aeolian processes dominating, reflecting the arid conditions. The SEM surface textures of quartz grains on the Xiao Gangou slope are different from other representative sedimentary environment’s, and have their own typical feature combinations, standing for characteristics of quartz grains formed under dry erosion environment of the Tibetan Plateau. High relief particles appear most among the SEM microtextures. Besides, other major textures are listed as follows: subangular particle, subedge ridge, con- choidal breakage fracture, parallel cleavage, dissolution pits and grooves, siliceous sphere, siliceous scales, and silicon dioxide crystallizing. Relative frequency distributions of the various surface textures recorded on quartz grains suggest that the slope cause of formation was related with weathering and chemical action without glaciations. Characteristics of particle shape indicate a short transport of deposition; the physical characteristics suggest that they were formed in a setting of physical weathering and impacting; the chemical ones were in connection with alkaline, climate warm and cold changes and locally well water-supplying conditions, as well as calm environment. The Xiao Gangou profile suggests the following climate change process: from cold-wet (dated 30-17 ka) to warm-dry surroundings (from 14 ka to now) since the last glaciation. Comparing with the profile of Xiao Nanchuan locating in the upstream of the Golmud River, the differences in lithological character, landform, and hydrothermal condition resulted in distinctions between their sedimentary features, reflecting the vertical zonality of geomorphic process.
中文关键词	格尔木河 ; 坡积 ; 石英砂 ; SEM特征 ; 环境重建
英文关键词	the Golmud River slope deposits quartz grains SEM environment reconstruction
语种	中文
国家	中国
收录类别	CSCD
WOS类目	GEOLOGY
WOS研究方向	Geology
CSCD记录号	CSCD:4395446
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/226488
作者单位	北京大学城市与环境学院, 北京 100871, 中国
推荐引用方式 GB/T 7714	张梅,陈艺鑫,银森录,等. 格尔木河小干沟坡积沉积特征与古环境重建[J],2011,34(6):890-903.
APA	张梅,陈艺鑫,银森录,张敬春,李川川,&刘耕年.(2011).格尔木河小干沟坡积沉积特征与古环境重建.干旱区地理,34(6),890-903.
MLA	张梅,et al."格尔木河小干沟坡积沉积特征与古环境重建".干旱区地理 34.6(2011):890-903.