摘要
酒东沙地位于河西走廊中段的张掖绿洲和酒泉绿洲之间,其风沙环境的变化对周边的人类活动至关重要。与其他沙区相比,该沙地的研究基础相对薄弱。对酒东沙地表层风沙沉积物的粒度、化学元素和矿物特征进行了研究,并探讨了其环境指示意义。结果表明:酒东沙地表层风沙沉积物平均粒径218~308μm,以中沙和细沙为主,分选性良好,偏度近对称,峰度中等;沉积物粒径总体上由北向南逐渐变细;在近东西向的两条断面上,位于沙地腹地的表层风沙沉积物自西向东逐渐变细,而沙地南缘则呈现相反的规律;酒东沙地表层风沙沉积物中跃移组分含量最高,其次为短距离悬移组分、蠕移组分和长距离悬移组分。常量元素以SiO_(2)为主,CaO和MgO含量存在顺主导风向减少的规律;微量元素除Cr、Ni和Co表现出明显的富集特征外,其余元素均出现不同程度的亏损。矿物以硬矿物石英和长石为主,其次是白云石,其他矿物含量极少;矿物成分成熟度指数Q/TF较低。酒东沙地表层风沙沉积物处于基本未受或遭受了较弱的化学风化的初期,以物理风化过程为主,推测其形成于干冷、弱化学风化和弱成壤环境下。
Jiudong Sandy Land is located between Zhangye Oasis and Jiuquan Oasis in the middle Hexi Corridor and its aeolian process is influential to the surrounding hμman activities.In this paper,the grain size,chemical elements and mineral characteristics of the surface aeolian sands of Jiudong Sandy Land were investigated.The results show that:(1)The average grain size of aeolian sands on the surface of Jiudong Sandy Land is between 218-308μm and mainly consists of mediμm sand and fine sand with good sorting,nearly symmetrical skewness and kurtosis is moderate.The aeolian sands generally become finer from north to south;the aeolian sands in the hinterland of the sandy land gradually become finer from west to east,while the southern edge of the sandy land presents the opposite phenomenon.The content of saltation component is the highest,followed by short distance suspension component,creeping component and long-distance suspension component.(2)The major element is SiO_(2),and the content of CaO and MgO decreases along the dominant wind direction.Except for Cr,Ni and Co,trace elements show obvious enrichment while other elements are depleted to varying degrees.(3)The minerals are mainly hard minerals of quartz and feldspar,followed by dolomite,and the content of other minerals is very low.The mineral maturity index(Q/TF)is low.(4)The aeolian sands of Jiudong Sandy Land are in the initial stage of being basically free from or subject to weak chemical weathering,mainly in the process of strong physical weathering.It is speculated that they were formed in a dry and cold,weak chemical weathering and weak pedogenic environment.
作者
郭雪阳
杨林海
程良清
胡光印
胡菁菁
Xueyang Guo;Linhai Yang;Liangqing Cheng;Guangyin Hu;Jingjing Hu(School of Geography and Tourism,Shaanxi Normal University,Xi'an 710119,China)
出处
《中国沙漠》
CSCD
北大核心
2023年第4期17-30,共14页
Journal of Desert Research
基金
国家自然科学基金项目(42271004)。
关键词
风沙沉积物
粒度
元素
矿物
酒东沙地
aeolian sands
particle size
element
mineral
Jiudong Sandy Land
