干旱区生态环境知识资源中心(Arid): 临夏盆地晚更新世沉积物粘土矿物的特征及其古气候指示

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	临夏盆地晚更新世沉积物粘土矿物的特征及其古气候指示
其他题名	Clay Mineralogy and Its Palaeoclimatic Indicator of the Late Pleistocene in Linxia Basin
	洪汉烈; 于娜; 薛惠娟; 朱云海; 向树元; 张克信
ISSN	1000-8527
出版年	2007
卷号	21 期号:2 页码:406-414
中文摘要	利用X射线衍射、扫描电子分析方法,对临夏地区塔湾黄土沉积物的粘土矿物学特征及其古气候指示作用进行了深入研究.结果表明:晚更新世的黄土沉积物风成黄土或经过表生风化改造形成的古土壤,其粘土矿物组成主要为伊利石、绿泥石、伊/蒙混层粘土矿物、高岭石和少量的坡缕石,沉积物中高岭石、伊利石/蒙脱石、伊利石和绿泥石矿物组合,指示物源区经历了气候从湿润变为冷干的转变.沉积物中伊利石结晶度的测量结果显示,其(001)衍射峰的半高宽在0.23°～0.86°之间,不同岩性层中伊利石结晶度存在明显的差别,伊利石结晶度存在着两个明显的峰值区,这表明临夏地区晚更新世的气候变化经历了从湿润冷干湿润冷干的两个周期性的演化,而且晚期与早期相比更加湿润同时又更为冷干.沉积物中既有自生成因的坡缕石,又有碎屑成因的坡缕石.沉积物中自生成因坡缕石和碎屑成因坡缕石均稳定存在的现象表明,本区晚更新世的古气候是以干旱为特征,年均降雨量在300 mm左右.
英文摘要	Clay mineralogy of the Late Pleistocene loess sediments in Tawan, Linxia, northwestern China, was investigated using X-ray diffraction (XRD) and scanning electron microscopy(SEM). The results show that mineral compositions of both the loess sediment and the palaeosol are illite, chlorite, mixed-layer illite-smectite, kaolinite, and minor palygorskite. The mineral assemblage of illite, chlorite, mixed-layer illite-smectite, and kaolinite suggests that the palaeoclimate of the source area changed from warm and humid to cold and arid. The Kubler index of illite crystallinity(IC) , full width half maximum of the (001) reflection, ranges from 0. 23° to 0.86°. It shows significant difference between the lithological layers. However, the IC curve presents two peaks, suggesting that the palaeoclimate of Late Pleistocene in Linxia experienced two cycles of warm and humid to cold and arid, and the late cycle was more humid and more arid comparative to the former one. Both authigenic and detrital palygorskite occured in the Late Pleistocene loess sediments, the stability of palygorskite indicates that the annual rainfall was around 300 mm during the Late Pleistocene.
中文关键词	粘土矿物 ; 结晶度 ; 坡缕石 ; 晚更新世 ; 临夏盆地
英文关键词	clay minerals crystallinity palygorskite Late Pleistocene Linxia basin
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:2824383
资源类型	期刊论文
条目标识符	http://119.78.100.177/qdio/handle/2XILL650/221616
作者单位	(武汉)中国地质大学,地球科学学院, 武汉, 湖北 430074, 中国
推荐引用方式 GB/T 7714	洪汉烈,于娜,薛惠娟,等. 临夏盆地晚更新世沉积物粘土矿物的特征及其古气候指示[J],2007,21(2):406-414.
APA	洪汉烈,于娜,薛惠娟,朱云海,向树元,&张克信.(2007).临夏盆地晚更新世沉积物粘土矿物的特征及其古气候指示.,21(2),406-414.
MLA	洪汉烈,et al."临夏盆地晚更新世沉积物粘土矿物的特征及其古气候指示".21.2(2007):406-414.