【作者】 席明杰；

【导师】 马生明；

【作者基本信息】 中国地质科学院 ， 地球化学， 2009， 硕士

【摘要】 地球化学异常成因研究是评价其成矿前景、矿化类型及部署勘查、勘探工作的前提,但是在以往地球化学勘查工作中很少涉及。本文借鉴稳定同位素示踪成矿物质来源的方法和原理,利用内蒙古自治区乌奴格吐山、星山、白乃庙试验区、江西城门山试验区硫同位素组成资料,尝试利用硫同位素组成特征来判断地球化学异常成因,取得了预期成果。乌奴格吐山试验区硫同位素组成为.1.3‰～+3.2‰;白乃庙试验区硫同位素组成-2.8‰～+13.8‰;城门山试验区硫同位素组成为-0.3‰～+5.7‰;垦山试验区硫同位素组成变化为+3.2‰～+4.3%0。通过各个试验区Cu矿化体、Cu异常地段硫同位素组成特征对比研究发现,在每个试验区内,与Cu矿化有关的矿化体和异常地段硫的来源基本一致,各试验区矿体及外围围岩中的成矿物质与异常物质组分来自同一源区。对在相同地质作用过程中形成的矿床和异常而言,与其共生的硫同位素组成基本是一致的,说明形成矿床的成矿物质和形成异常的异常组分物质来源基本是一致的,这为利用硫同位素组成特征判断地球化学异常成因提供了依据,同时也证实利用硫同位素组成特征探讨地球化学异常成因是可行的。乌奴格吐山试验区矿体、矿化围岩的成矿物质及外围同岩中异常的组分物质来自下地壳;白乃庙试验区矿体、蚀变带中的成矿物质及外围围岩中异常的组分物质的硫来自地壳深部,并受到了循环地壳和海水的混染;城门山试验区矿体、矿化围岩的成矿物质及外围围岩中异常的组分物质来自下地壳或上地幔;垦山试验区的异常组分物质来自下地壳,且受到后期热液作用的影响。研究发现,垦山试验区和乌奴格吐山、白乃庙、城门山试验区的硫同位素组成存在明显差异,根据该区硫同位素组成推断该试验区的Cu等多金属地球化学异常是由后期热液作用形成的,从而认为该区不具备形成斑岩型矿床的条件,此前有研究者推断此Cu异常的成因与斑岩矿化有关,由此针对该异常的地质找矿及工作部署应该围绕热液矿床进行,为该区下一步勘查工作部署提供了依据。本文通过对硫同位素组成特征的探讨,认为硫同位素作可以作为异常成因判断指标应用在矿产勘查阶段,为异常成矿前景评价提供依据,为异常区地质勘查工作部署提供指导,不仅拓展了硫同位素在地质学研究中的应用领域,更重要的是为地球化学异常成矿前景评价提供了有利证据,对提高地球化学勘查应用基础理论水平及找矿效果具有重要意义。更多还原

【Abstract】 The Genesis of geochemical anomaly, one of the key factor for the evaluation of its exploration potential, minerlization type, and deployment to prospecting and exploration work, has not been taken into account in the past geochemical exploration. Based on the method and principle of the tracing in the source of mineralization material from the stable isotope, we use the sulfur isotopic indexes from Wunugetushan, Kenshan, Bainaimiao,Inner Mongolia, and Chengmenshan area in Jiangxi, and try to use the characteristics of sulfur isotopic composition (δ³⁴S) to determine the causes of geochemical anomalies. Further more, some expected results have been obtained.The sulfur isotopic analysis shows that the pyrite from Wunugetushan area haveδ³⁴S values that range between -1.3 and +3.2‰, it indicate that the sulfur from the lower crust. Theδ³⁴S values abtained from Bainaimiao area have a range between -2.8 and +13.8‰, and most of them are negatives, which indicate that the sulfur of this area had suffered the mixing of crustal and marine pollution.Chengmenshan area haveδ³⁴S values that range between -0.3 and +3.2‰, it indicate that the sulfur from the lower crust or upper mantle. Theδ³⁴S values abtainede from Kenshan area have a range between +3.2 and +4.3‰, it indicate that the sulfur source is lower crust and has suffered the influence of hydrothermal fluids activities of the later stage.By comparing the characteristics of sulfur isotopic composition in Cu mineralization and Cu abnormality from one region with others, we have found that the related source of sulfur in element in Cu mineralization and Cu abnormality are primarily unanimous in earch testing region. For a deposit or abnormality which was formed in the same geological processes, the sulfur isotopic composition of symbiotic are particularly same, which indicated that the mineralization material and abnormality materal were from the same source area. This provides a basis for using the sulfur isotope composition to determine the causes of geochemical anomalies, and it indicates that using sulfur isotopic composition to determine the causes of geochemical anomalies is feasible. In the Wunugetu Moutain region, some researches showed that the metallogenic material of the orebodies and mineralized wallrocks came from the lower crust, as well as the composition of anomalies in the external wallrocks. In another region-Bainaimiao, the similar situation occurred that the sulfurs from the metallogenic material of the orebodies and mineralized wallrocks and the composition of the anomalies in the external wallrocks was resulted from the deep section of the crust, while they were contaminated by the crust cycle and the seal water. In the last two test region also showed the similar situation.In the Chenmenshan region, the metallogenic material of the orebodies and mineralized wallrocks came from the lower crust or the upper mantle, as well as the composition of anomalies in the external wallrocks.In the Kenshan test region, the composition of anomalies, which was influenced by the hydrothermal of later stage, came from the lower crust.The result shows that sulfur isotopic compositon in Kenshan area are significantly different from Wunugetushan, Bainaimiao and Chengmenshan area. According to the characteristics of sulfur isotopic composition, mineralogy and geochemistry in these area, and inferred that such as Cu multi-element anomalies are formed by the late hydrothermal. Furtherly, the area does not have the conditions for the formation of porphyry deposit; in addition, some prewiews researchs show that the Cu abnormities are relatd to porphyry mineralization. Geological prospecting and deployment for these abnormities should be carried out around the hydrothermal deposit; this will provide the basis for the next exploration.Based on the characteristics of sulfur isotope composition, it can be used in mineral exploration as a indicator applied to determine the causes of geochemical anomalies. More over, it provides the basis for evaluating the prospect of its mineralization, and the guidance for the geological survey work in anormaly area. Not only it expands the applications of sulfur isotopes in geology studies, but also provides a favorable evidence for evaluating the prospects of the geochemical anomalies. Besides that, it obviously improve the prospect results and the level of basic theory of geochemical exploration.更多还原