新疆帕米尔高原塔什库尔干地区冰川融水锶同位素特征及其环境意义  

Characteristic and environmental significance of strontium isotope in glacial meltwater of the Tashkurgan area in Pamirs,Xinjiang

作　　者：仝晓霞[1] 马武明[2] 孙兴乐 

机构地区：[1]中国地质环境监测院,北京100081 [2]天津市地质调查研究院,天津300191 [3]河南省地质环境规划设计院有限公司,郑州450000

出　　处：《环境化学》2017年第4期830-838,共9页Environmental Chemistry

基　　金：国家自然科学基金(41402221);中国博士后科学基金(2013M540999)资助~~

摘　　要：本文研究了帕米尔高原地区冰川融水的Sr同位素组成特征,并且结合水化学和氢氧同位素结果进行讨论.结果表明,该区以HCO_3-Ca(Ca-Mg)和HCO_3-SO_4-Ca-Mg水为主;冰川融水矿化度低,水化学类型简单,NO_3^-离子含量很少,是研究冰川融水氢氧同位素特征和用锶同位素研究水-岩作用的理想地区.研究区冰川融水的^(18)O和~2H具有明显的高度效应,δ^(18)O-δ~2H关系水点均位于世界降水线的左上方,显示了寒冷气候条件下,冰川融水^(18)O和~2H同位素特征;本研究应用^(87)Sr/^(86)Sr比值与1/[Sr^(2+)]相关性以及^(87)Sr/^(86)Sr、[Sr^(2+)]/[Na^+]比值的相关性发现,塔什库尔干河流域的上游西南部喀喇其库尔河一带是以硅酸盐岩为主的分布区,其特点是高^(87)Sr/^(86)Sr比值和低[Sr^(2+)]/[Na^+]比值,南部是以碳酸盐岩为主的分布区,其特征是低^(87)Sr/^(86)Sr比值和高[Sr^(2+)]/[Na^+]比值;到了中游和下游,河水都是混合水,其中靠近上游水点以低^(87)Sr/^(86)Sr比值和高的1/[Sr^(2+)]比值为特征,而下游则以低^(87)Sr/^(86)Sr比值和小的1/[Sr^(2+)]比值为特征,这些特点与混合水的来源和流经区的岩性有关;本研究还发现,氘过量参数d值是识别大气降水补给河水或地下水的重要指标,可用于研究该地区古气候的演变.In this paper,we studied the characteristics of Sr isotopic composition of glacial melt water in the Pamirs region,and discussed the combined water chemistry and hydrogen and oxygen isotope results. The results show that the water chemical type are HCO3-Ca（Ca-Mg） and HCO3-SO4-Ca-Mg. Glacier water mineralization degree is low,and the water chemistry type is simple. What’ s more,it has a rarely NO3-ion content. So,this area is the ideal area to study the strontium isotope of water rock interaction and hydrogen oxygen isotope characteristics of glacial melt water. The18O and2H of glacier melt water in the study area have obvious height effect. The relationship of water points of δ18O-δ2H are on the top left of the precipitation line. It shows the characteristics of18O and2H inthe cold climate conditions. This study applied87Sr/86Sr ratio and the relativity of 1/[Sr2＋] ratio,and the relativity of87Sr/86Sr ratio and [Sr2＋]/[Na＋]ratio,found that Tashikuergan river drainage area upstream southwest kalaqi Kur river area is dominated by silicate rock distribution. It is characterized by high87Sr/86Sr ratio and low [Sr2＋]/[Na＋]ratio. The southern part is dominated by carbonate rocks,characterized by low87Sr/86Sr ratio and high [Sr2＋]/[Na＋] ratio. In the middle and lower reaches,the river is the mixed water,with low near the upstream water points among them87Sr/86Sr ratio and high ratio of 1/[Sr2＋] was characterized,and downstream at low87Sr/86Sr ratio and small ratio of87Sr/86Sr,characterized by these characteristics associated with the sources and flows through the lithology of the mixed water. This study also found that the deuterium excess parameter d is an important index to identify the recharge of the river water or groundwater. It can be used to study the evolution of the ancient climate in the region.

关 键 词：帕米尔高原 塔什库尔干 冰川融水(水-岩作用) 锶同位素 氘过量 

分 类 号：P597[天文地球—地球化学] P342[天文地球—地质学]