内蒙古河套地区多目标区域地球化学调查成果及其意义

Results and Significance of Multi-purpose Geochemical Mapping in the Hetao Area,Inner Mongolia

报道了内蒙古河套地区多目标区域地球化学调查结果及其对当地资源勘察、古湖泊环境、城市污染和地方病研究等方面的意义。调查结果显示,河套地区土壤主要富集Mg、Ca等碱性物质,西部狼山一带的多金属矿区应重视Ga、Ge、Tl等分散元素矿床的研究,乌拉山到大青山一带是寻找绿岩型金矿的有利地区。-20目粒级的土壤元素含量反映了河套地区的元素地球化学特征,同时不同成土母质决定了不同的元素富集与贫化特征,狼山山前冲积扇中是一套以多金属及分散元素为主的异常组合。河套地区的城市区内存在Pb、Hg、C、Ag、Au、P、Cd等元素异常的共同特征。古湖泊区与现代乌梁素海均表现F、Mo、U、CaO、MgO、Sr、C、I为正异常、S iO2为负异常的特征。同时现代乌梁素海沉积物中富集有机碳、N、P、Se,pH值较低;古湖泊则相反。河套地区氟中毒区与古湖泊、古河道以及白垩系地层分布范围一致,发病程度与高氟地下水含量呈正比关系。砷中毒与砷的全量和As3+共同作用有关,砷的价态对砷中毒产生影响,As3+含量越高,病况越严重。

This paper gives some results from multi-purpose geochemical mapping in the Hetao area, Inner Mongolia. The soil of the Hetao area is rich in alkaline materials such as Mg and Ca. Attention should be paid to the mineralization of some dispersed elements such as Ga, Ge and T1 in Langshan polymetallie mining field. The Wulashan-Daqingshan is the favorable area for prospecting greenstone type gold deposit. Element contents of the soil with the granularity in 〈 20 mesh reflect the geochemical characteristics of Hetao area. Parent material is the first factor that determines the elements＇ concentrations. For example, piedmont alluvial fan of Langshah is an abnormal sedimentary assemblage mainly with polymetallic material and dispersed elements. The cities in Hetao area are all characterized by element anomalies of Pb, Hg, C, Ag, Au, P, Cd and so on. In ancient lake area and modern Wuliangsu lake, F, Mo, U, CaO, MgO, St, C and I appear to positive anom- aly, and SiO2 negative anomaly. Meanwhile, modem Wuliangsu lake sediments are rich in organic carbon, N, P and Se with low pH; and the ancient lakes are on the contrary. Fluorosis areas in Hetao have the same distri- bution with ancient lake, old channel and Cretaceous formation, and epidemic degree is proportional to volume of underground water with high fluoride. Arsenic poisoning is relevant to the interaction of total As and As3＋, and the valence of As affects the arsenic poisoning. The higher the As3 ＋ content is, the more serious the arsenic poisoning is.