扎当冰川雪坑中不同粒径微粒元素和矿物组成特征  

Mineral and Elemental Characteristics of Microparticles with Different Size Fraction in Snowpits from Zadang Glacier

作　　者：余光明[1] 徐建中[1] 康世昌[2] 黄杰[2] 任贾文[1] 

机构地区：[1]中国科学院寒区旱区环境与工程研究所冰冻圈科学国家重点实验室,兰州730000 [2]中国科学院青藏高原研究所,北京100085

出　　处：《环境科学》2011年第11期3264-3270,共7页Environmental Science

基　　金：国家自然科学基金项目(40901043);冰冻圈科学国家重点实验室自主课题项目(SKLCS-ZZ-2008-01)

摘　　要：为了研究雪冰中不溶性微粒的矿物和元素组成及其来源,2009年5月和7月在念青唐古拉山扎当冰川垭口采集了2个雪坑样品,采用质子激发X荧光分析(PIXE)和X射线衍射定量分析方法(XRD)测定了不同季节粗细微粒(d>10μm和0.22μm<d<10μm)的元素和矿物组成.结果表明,微粒矿物组成主要为石英、云母、方解石,此3种矿物比重分别占粗细微粒已检测矿物的71.5%和76.5%.微粒元素组成以Si、Al、Fe、K、Mg、Ca等地壳元素为主,6种元素分别占粗细微粒所测元素浓度的97%和85.1%,S、Cl、P等元素在细微粒中也占相当的比例.粗微粒元素组成的季节变化较小,细微粒元素组成的季节波动则较大.元素富集因子的研究表明,Mg、Ca、Si、K、Ca、Ti、V、Mn等元素多来自于自然源;在夏季风期间细微粒中Sc、P、Cr、S、Cl等元素有明显的富集.气团轨迹显示夏季风期间气团主要来自南亚地区,这些元素可能来自南亚污染物质的输入;而非季风期间气团主要来自西亚和南亚的干旱及半干旱区.结果表明,扎当冰川雪坑中粗微粒可能主要源于远源或局地矿物粉尘的贡献,细微粒化学组成受到人类污染物的干扰.In order to study the mineral and elemental composition of insoluble microparticles（IP） in snow/ice,two snowpits were collected from the Zadang Glacier in Mt.Nyainqentanglha（30.47°N,90.65°E,5 800 m a.s.l） in May and July,2009,and IP samples were investigated.The measurements of mineral composition with different size fractions（d10 μm and 0.22 μmd10 μm） were carried out using Particle-induced X-ray emission（PIXE） and X-ray diffraction analysis（XRD）.The main mineral components of both coarse and fine IP are quartz,mica and calcite,accounting for 71.5% and 76.5%,respectively.The crustal elements concentrations（e.g.Si,Al,Fe,K,Mg and Ca） are 97% and 85.1% of total coarse/fine IP,while S,Cl and P take fairly proportion in fine microparticles（d10 μm）.Seasonal variability of mineral composition in coarse microparticles（d10 μm） is not obviously;However it＇s significantly in fine IP.Enrichment factors（EF） analysis reveals that several elements（e.g.Sc,P,Cr,S and Cl） in fine IP during monsoon season have high values which indicate these elements may be influenced by anthropogenic activities.Backward air mass trajectory analysis suggests that air masses in this region mainly originate from the South Asia areas during monsoon season,and air masses mainly come from arid/semi-arid region in the South and West Asia during non-monsoon season.Therefore,anthropogenic pollutants from the South Asia may be transported by the summer Indian monsoon to the Zadang glacier area.The coarse IP may derive from the local or remote mineral dust,and chemical compositions of fine IP interfere with anthropogenic pollutants.

关 键 词：扎当冰川 不溶性微粒 质子激发X荧光(PIXE) X射线衍射(XRD) 富集因子 后向轨迹 

分 类 号：X131[环境科学与工程—环境科学]