气候变化领域集成服务门户(CCPortal): 青藏高原中部扎布耶茶卡142ka以来石英砂表面特征及环境意义

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	青藏高原中部扎布耶茶卡142ka以来石英砂表面特征及环境意义
其他题名	Surface Textures on Quartz Grains from the Zhabuye Saline Lake in the Middle Tibet Plateau since 142 ka BP
	李明慧; 康世昌; 郑绵平
发表日期	2008
ISSN	1000-0240
卷号	30 期号:1 页码:125-131
中文摘要	石英抗风化能力强，表面特征保留了许多环境信息，用扫描电镜方法对石英砂表面结构进行了研究．结果表明：扎布耶茶卡的石英颗粒以次棱角状、次圆状为主，撞击坑、贝壳状断口、平行解理和水下磨光面等机械特征出现频率较高；化学特征有二氧化硅沉淀、蜂窝状溶蚀面、硅质球和蚀坑/洞．石英颗粒经历冲洪积作用，搬运至湖泊后又经历了水下机械和化学作用．在142～60kaBP扎布耶茶卡湖区气候寒冷，但无冰川作用存在，石英颗粒搬运距离近，机械特征主要是强烈的物理风化与冲洪积作用形成的，化学特征与弱的水动力条件有关；8．5～3．7kaBP湖区气候温暖，但变化频繁，湖水进一步成化、退缩，山坡后退变缓，机械特征主要由物理风化及搬运中的碰撞造成，化学特征则与弱的水动力条件和高盐环境有关。
英文摘要	Many attempts have been made with scanning electron microscopy （SEM） to correlate quartz sand micro-morphology with sedimentary processes, depositional environments and the palaeo-environmental reconstruction. The purpose of this study is to examine the surface textures of quartz grains to reconstruct the palaeo-environment in Zhabuye Saline Lake. Two sedimentary sections are recovered in the north and terrace of the lake. The sediment in the terrace is dated by U series to be approximately 142-60 ka BP, and the sediment in the northern lake is dated by 14C to be 8.5-3.7 ka BP. The surface textures on quartz grains analyzed by SEM have many physical characteristics such as impact pits, conehoidal breakage fracture, polish surface, parallel cleavage, and chemical characteristics such as abraded pits, honeycombed solution surface, siliceous sphere and SiO2 precipitates. During 142-60 ka BP the physical characteristics in grains showed an effect of strong physical weathering and alleviation from a short transport in cold-dry conditions, and the chemical ones showed that they formed in calm water without glaciation. From 8.5 to 3.7 ka BP the physical characteristics suggested that they were formed in a setting of physical weathering and impact, and the chemical ones kept in touch with calm and high salinity water, indicating the climate became warmer relatively but changed frequently with more briny lake water and low angle hillside.
关键词	石英砂表面结构扫描电镜湖泊青藏高原
英文关键词	quartz sands;surface textures;SEM;saline lake;Tibet Plateau
语种	中文
来源期刊	冰川冻土
来源机构	中国科学院西北资源环境生态研究院
文献类型	期刊论文
条目标识符	http://gcip.llas.ac.cn/handle/2XKMVOVA/89697
推荐引用方式 GB/T 7714	李明慧,康世昌,郑绵平. 青藏高原中部扎布耶茶卡142ka以来石英砂表面特征及环境意义[J]. 中国科学院西北资源环境生态研究院,2008,30(1):125-131.
APA	李明慧,康世昌,&郑绵平.(2008).青藏高原中部扎布耶茶卡142ka以来石英砂表面特征及环境意义.冰川冻土,30(1),125-131.
MLA	李明慧,et al."青藏高原中部扎布耶茶卡142ka以来石英砂表面特征及环境意义".冰川冻土 30.1(2008):125-131.