新疆独山子泥火山沉积物及孔隙水的地球化学特征与流体来源  

Geochemical Features and Origins of Pore Fluids and Sediments of the Mud Volcanoes in Southern Margin of the Junggar Basin, Xinjiang, Northwestern China

作　　者：黄华谷[1,2] 李牛[2] 王钦贤[2] 陈多福[2] 

机构地区：[1]广东省地质调查院,广东广州510080 [2]中国科学院广州地球化学研究所边缘海地质重点实验室,广东广州510640

出　　处：《大地构造与成矿学》2015年第2期325-333,共9页Geotectonica et Metallogenia

基　　金：中国科学院西部行动计划项目(编号:KZCX2-XB3-03);国家自然科学基金(批准号:41273112和41273041)联合资助

摘　　要：对陆地泥火山流体来源及其向地表渗漏过程中的改造作用开展研究,有利于加深理解泥火山释放甲烷的碳排放过程。新疆准噶尔盆地南缘独山子泥火山柱状沉积物和地表沉积物的矿物和元素组成,以及沉积物孔隙水离子组成等的分析结果显示,泥火山沉积物孔隙水Na+和Cl–间具有很好的正相关性,具有比海水高的Na+/Cl–和Li+/Cl–值、低的K+/Cl–和Mg2+/Cl–。泥火山沉积物与围岩相比,富集伊利石、绿泥石和方解石,缺少蒙脱石,富集Ca、亏损Si,这些变化主要与黏土矿物的脱水转变有关。表明泥火山流体主要来源于深部低盐度沉积物孔隙水,但经历了地表的蒸发作用,并混合了大气降水。Fluid sources and geochemical processes involved in terrestrial mud volcanoes are of great significance for understanding the chemical processes of methane emission to the atmosphere. Mud sediments ejected from the Dushanzi mud volcano, which is located along the southern margin of the Junggar Basin, northwestern China, were collected by hand core sampling. The ionic compositions of the pore fluids, minerals and major elements of the ejected sediments and surface sediments were analyzed. The results showed that significant correlation between Cl– and Na＋ in pore fluids. Relative to seawater, the mud volcano fluids have higher ratios of K＋/Cl–and Mg2＋/Cl–and lower ratios of Na＋/Cl–and Li＋/Cl–. The mud sediments are enriched in illite, chlorite and calcite but depleted in smectite relative to the host rocks of the mud volcano. The changes in the mud and pore fluids are mainly related to clay mineral dehydration. The fluids were mainly derived from ancient sedimentary low salinity pore fluids, but modified by the surface evaporation and meteoric surface water.

关 键 词：泥火山 孔隙水 沉积物 地球化学 改造作用 流体来源 新疆 

分 类 号：P588.2[天文地球—岩石学] P595[天文地球—地质学]