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广东凡口铅锌矿碳、氧同位素地球化学特征及其地质意义 总被引:3,自引:0,他引:3
广东凡口超大型铅锌矿床产于泥盆系台地碳酸盐岩中,矿床成因仍存在较大争议。通过含矿地层岩石以及矿石系统的碳、氧同位素分析研究,发现紫色砂岩的褪色蚀变和碳酸盐岩的白云石化与盆地卤水作用密切相关,褪色蚀变砂岩中的碳酸盐胶结物具有显著低的δ^13C和δ^18O值,与矿石中碳酸盐矿物相似,白云石化的碳酸盐岩之δ^13c和δ^18... 相似文献
894.
Makoto Yamada Shinji Ohsawa Kohei Kazahaya Masaya Yasuhara Hiroshi Takahashi Kazuhiro Amita Hideo Mawatari Shin Yoshikawa 《Journal of Geochemical Exploration》2011
To understand deep groundwater flow systems and their interaction with CO2 emanated from magma at depth in a volcanic edifice, deep groundwater samples were collected from hot spring wells in the Aso volcanic area for hydrogen, oxygen and carbon isotope analyses and measurements of the stable carbon isotope ratios and concentrations of dissolved inorganic carbon (DIC). Relations between the stable carbon isotope ratio (δ13CDIC) and DIC concentrations of the sampled waters show that magma-derived CO2 mixed into the deep groundwater. Furthermore, groundwaters of deeper areas, except samples from fumarolic areas, show higher δ13CDIC values. The waters' stable hydrogen and oxygen isotope ratios (δD and δ18O) reflect the meteoric-water origin of that region's deep groundwater. A negative correlation was found between the altitude of the well bottom and the altitude of groundwater recharge as calculated using the equation of the recharge-water line and δD value. This applies especially in the Aso-dani area, where deeper groundwater correlates with higher recharge. Groundwater recharged at high altitude has higher δ13CDIC of than groundwater recharged at low altitude, strongly suggesting that magmatic CO2 is present to a much greater degree in deeper groundwater. These results indicate that magmatic CO2 mixes into deeper groundwater flowing nearer the magma conduit or chamber. 相似文献
895.
对超高压变质岩中含水矿物和名义上无水矿物的地球化学研究,极大地深化了我们对大陆碰撞带地壳俯冲和折返过程中流体体制的认识。就流体体制和化学地球动力学来说,有关研究在大别-苏鲁造山带进行的最为详细,因此已经成为研究大陆俯冲带变质的典型地区。本文以大别-苏鲁造山带为对象,从矿物水含量的角度,结合稳定同位素论述了大陆俯冲带流体活动。超高压变质岩中名义上无水矿物含有大量的水,以结构羟基和分子水形式存在。名义上无水矿物中结构羟基和分子水出溶与含水矿物分解共同构成了折返过程中退变质流体的主要来源。名义上无水矿物所释放的水以富集轻的氢氧同位素为特征,而含水矿物分解则提供了富集D的流体来源。折返过程中,名义上无水矿物降压脱水存在亏损D的分子水的优先丢失和不同形式水之间的相互转化。不同岩性的水含量差异导致了它们在折返过程中不同的流体活动行为。大陆板块俯冲和折返过程中,在不同矿物、不同岩性以及板片不同部位之间存在水的再分配;板片的一部分作为富水流体的源,而另一部分可能作为汇。 相似文献
896.
In order to recognize the impact of aqueous medium on gas yields and the kinetic behaviors of hydrogen isotope fractionation during organic matter thermal degradation, the gold tube apparatus was used to conduct thermal simulation experiments by mixing the nC18 with the water of different properties and proportions. The yields of natural gas components, the relation among hydrogen isotope composition of each component and the experimental temperatures vs. heating rates have been obtained, and the results indicate that under the higher temperature conditions, the hydrous experiment has obvious impact on gas yields, such as when more water is added, higher amounts of hydrocarbon gas and H2 are yielded, and the existence of water obviously prolongs the temperature interval with the existence of heavy hydrocarbon gas. It also shows that the hydrogen isotope of hydrocarbon gas generated by the hydrous experiment is obviously lighter than that generated by the anhydrous experiment, and with the increasing amount of added water, the δD value of hydrocarbon gas gradually decreases. Compared with gas yields, the variation of δD value is more sensitive to aqueous medium in the thermal simulation experiment. However, compared with the amount of the added water, the aqueous medium property has smaller impact on the gas yields, which still shows the inherit effect on hydrogen isotope composition of aqueous medium. Through the model simulation and the isotope fractionation behavior analysis, it is validated that the hydrogen isotope fractionation process can be well described by the chemical kinetic model. The difference of reaction fraction of normal methane and D-containing methane is large, corresponding to the same activation energy. The content of normal methane is obviously higher in the part with lower activation energy, while the content of D-containing methane is higher in the part with higher activation energy. Therefore, it will result in larger hydrogen isotope fractionation amplitude, and the δD values will be more sensitive to the variation of maturity. Meanwhile, the average activation energy of methane generation from nC18 in the hydrous experiment is higher than that in the anhydrous experiment, and the greater amount of added water, the larger the average activation energy of methane generation reaction. This has laid foundation for its exploratory application in the study of gas reservoir forming history and the gas-source correlation, which indicates the research and application prospects in this orientation. 相似文献
897.
广域电磁法深部找矿实验效果 总被引:1,自引:0,他引:1
介绍了广域电磁法的基本原理、特点及广域视电阻率的定义。在内蒙古自治区某银铅锌矿进行了实验勘探工作,解释和推断了地电异常,并和可控源音频大地电磁法的效果进行了对比。研究结果表明:广域电磁法可以用较小的发收距获得较大的探测深度,勘探效率和精度较高,用于寻找深部金属矿的效果明显。 相似文献
898.
江南隆起带中段新元古代花岗岩锆石U-Pb年代学和Hf同位素组成研究 总被引:5,自引:1,他引:4
对江南隆起带中段湘东西园坑岩体和赣西九岭岩体的LA-ICPMS锆石U-Pb年代学测定和LA-MC-ICPMS锆石Hf同位素原位分析测试表明:西园坑岩体形成于(804±3)Ma,赣西九岭岩体的年龄为(813±4)Ma和(823±2)Ma,均为新元古代花岗岩.上述三个样品的εHf(t)的加权平均值分别为0.68±0.71,... 相似文献
899.
900.
翠宏山铁多金属矿床成矿流体包裹体及硫同位素特征 总被引:1,自引:0,他引:1
对翠宏山铁多金属矿床成矿早期阶段钨钼矿体中的石英、成矿晚期阶段铅、锌、铜矿体中的萤石流体包裹体特征及均一温度、盐度的研究表明,从早期钨钼成矿阶段至晚期铅、锌、铜成矿阶段,侵入体内接触带至外接触带,经历了一个温度剧降和盐度显著增加的过程。钨钼成矿阶段成矿流体主要为岩浆热液流体,成矿过程为单一的成矿流体冷却过程; 在晚期铅、锌、铜成矿阶段,来自岩浆中的温度较高的热流体与围岩地层中的大气降水等低温、高盐度流体混合,使成矿流体温度剧降和盐度增高,导致铅、锌、铜等成矿物质的沉淀。辉钼矿和方铅矿的δ34S ( × 10-3 ) 测试结果表明,侵入体内接触带钨钼矿体的成矿物质主要来自岩浆热液; 围岩地层中铅、锌、铜矿体的成矿物质,除岩浆热液来源外,部分可能来自雨水对地层中硫酸盐岩中硫及其他成矿物质的淋滤。 相似文献