The Emeishan basalt has a high Cu background value (170×10-6 on average), and thus provides a ore-forming material source for copper ores. The collected samples were exposed in basalt lavas of the third segment o...The Emeishan basalt has a high Cu background value (170×10-6 on average), and thus provides a ore-forming material source for copper ores. The collected samples were exposed in basalt lavas of the third segment of the Emeishan basalt eruptive cycle. By using a set of automatically cycling glass apparatuses, weathering-leaching experiments by three kinds of rainwater on the collected samples were carried out in the open system (at normal temperature and normal pressure). The analysis results showed that the most intensive export of Cu occurred under acidic rainwater-induced weathering-leaching conditions, almost 2-3 orders of magnitude the export of Cu by mod-ern air rainwater, and 1-2 orders of magnitude higher than the export of Cu by CO2 rainwater. In addition, the total amount of Zn, Cu, U, Ni and Sr exported by acidic rainwater are greater than 1%. All this indicates that copper in the Emeishan basalt provided the copper source for Cu mineralization at the contact between the basalt and the Maokou Formation limestone at the bottom.展开更多
为揭示不同酸度降雨对石灰土-碳酸盐岩体系内岩溶碳汇效应的影响，以贵阳市花溪区历史降水量为参照，选取贵阳市青岩镇纯灰岩发育土壤与贵阳市花溪水库三叠纪大冶组纯灰岩为样本进行淋溶试验。测定了6个月时长内不同酸度降水﹑不同土壤...为揭示不同酸度降雨对石灰土-碳酸盐岩体系内岩溶碳汇效应的影响，以贵阳市花溪区历史降水量为参照，选取贵阳市青岩镇纯灰岩发育土壤与贵阳市花溪水库三叠纪大冶组纯灰岩为样本进行淋溶试验。测定了6个月时长内不同酸度降水﹑不同土壤深度下模拟石灰土-碳酸盐岩体系降水淋出液的 HCO-3﹑DOC含量和土壤呼吸速率，研究了模拟酸雨对石灰土-石灰岩体系碳汇的影响。结果表明：（1）在土壤深度10~50 cm 匀质状态的样本中，随着土壤厚度的增加，淋出液中 HCO-3含量逐渐增大﹑DOC含量逐渐减小﹑土壤呼吸速率逐渐增大，显示出土壤厚度对石灰土-碳酸盐岩体系的碳汇效应有着明显的影响；（2）在 pH=3.5~6.8的范围内，降水酸度的增强可以抑制岩溶作用与有机碳的溶解，并降低岩溶碳汇效应；（3）在日降水量90~230 mm 范围内，随着降水量的增大碳汇效应也会随之增强。展开更多
基金supported jointly by "National Basic Research Program of China (973) Program) (2007CB411401)the National Natural Science Foundation of China (Grant No. 40773035)
文摘The Emeishan basalt has a high Cu background value (170×10-6 on average), and thus provides a ore-forming material source for copper ores. The collected samples were exposed in basalt lavas of the third segment of the Emeishan basalt eruptive cycle. By using a set of automatically cycling glass apparatuses, weathering-leaching experiments by three kinds of rainwater on the collected samples were carried out in the open system (at normal temperature and normal pressure). The analysis results showed that the most intensive export of Cu occurred under acidic rainwater-induced weathering-leaching conditions, almost 2-3 orders of magnitude the export of Cu by mod-ern air rainwater, and 1-2 orders of magnitude higher than the export of Cu by CO2 rainwater. In addition, the total amount of Zn, Cu, U, Ni and Sr exported by acidic rainwater are greater than 1%. All this indicates that copper in the Emeishan basalt provided the copper source for Cu mineralization at the contact between the basalt and the Maokou Formation limestone at the bottom.
文摘为揭示不同酸度降雨对石灰土-碳酸盐岩体系内岩溶碳汇效应的影响，以贵阳市花溪区历史降水量为参照，选取贵阳市青岩镇纯灰岩发育土壤与贵阳市花溪水库三叠纪大冶组纯灰岩为样本进行淋溶试验。测定了6个月时长内不同酸度降水﹑不同土壤深度下模拟石灰土-碳酸盐岩体系降水淋出液的 HCO-3﹑DOC含量和土壤呼吸速率，研究了模拟酸雨对石灰土-石灰岩体系碳汇的影响。结果表明：（1）在土壤深度10~50 cm 匀质状态的样本中，随着土壤厚度的增加，淋出液中 HCO-3含量逐渐增大﹑DOC含量逐渐减小﹑土壤呼吸速率逐渐增大，显示出土壤厚度对石灰土-碳酸盐岩体系的碳汇效应有着明显的影响；（2）在 pH=3.5~6.8的范围内，降水酸度的增强可以抑制岩溶作用与有机碳的溶解，并降低岩溶碳汇效应；（3）在日降水量90~230 mm 范围内，随着降水量的增大碳汇效应也会随之增强。
