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系统分析了贵州都匀七星洞(QXD)洞穴系统中各组分(土壤水、滴水及其化学沉积物与土壤、基岩等)的锶同位素组成(87Sr/86Sr),结果显示,各组分的87Sr/86Sr比值特征差异显著.QXD-1#,4#和9#滴水87Sr/86Sr平均值分别为0.709568,0.709139和0.708761,其比值差异可能是由不同滴水点相应的渗流水运移路径、滞留时间和其他水文地质过程等因素不同所造成的.两端员模式计算表明,基岩(碳酸盐岩)溶解对1#,4#和9#滴水的贡献率分别为40.8%,57.6%和72.4%.基岩溶解贡献率与之前研究的各滴水δ13CDIC值没有正相关关系(基岩δ13C值为1.8‰),相反,基岩贡献率相对较低的1#,其δ13CDIC值最重(平均值?4.5‰),而贡献率相对较高的9#,其δ13CDIC值最轻(平均值?9.3‰),QXD-4#基岩贡献率高于1#低于9#,其δ13CDIC平均值(?8.6‰)却低于1#高于9#.由此可见,基岩的溶解对滴水稳定碳同位素的影响不是该洞穴不同滴水点间碳同位素巨大差异的主要原因,水体运移路径中,可能前期方解石沉积(PCP)过程的发生才是滴水δ13CDIC偏重的主导因素.此外,本研究还发现,1#和4#滴水对应次生化学沉积物87Sr/86Sr比值特征主要反映了上覆土壤系统(土壤水)与基岩溶解相对贡献变化,利用本地洞穴次生化学沉积物87Sr/86Sr指标表征上覆土壤风化强度及其变化是可行的,进而反映本区域季风气候信息.
The strontium isotopic compositions (87Sr / 86Sr) of each component (soil water, drip and sediment, chemical sediments and soils, bedrock, etc.) of the QXD cave system in Guizhou Province were systematically analyzed. The results showed that each component The 87Sr / 86Sr ratios of QXD-1 #, 4 #, and 9 # drip water were 0.709568, 0.709139 and 0.708761, respectively, and the difference in the ratio of 87Sr / 86Sr was probably caused by the corresponding seepage water transport paths at different drip points. Time and other hydrogeological processes, etc. The calculation of the two-member model shows that the contribution rates of bedrock (carbonate) dissolution to the drip rates 1 #, 4 # and 9 # are 40.8% and 57.6%, respectively 72.4%. The contribution rate of bedrock dissolution is not positively correlated with the δ13CDIC value of each drip studied in the previous study (bedrock δ13C value is 1.8 ‰). On the contrary, the bedrock contribution rate is relatively low, The value of 4.5 ‰), while the contribution rate of 9 #, the δ13CDIC value of the lightest (average 9.3 ‰), QXD-4 # bedrock contribution rate higher than 1 # less than 9 #, and its δ13CDIC average (? 8.6 ‰) is lower than 1 # higher than 9 #. Thus, the effect of bedrock dissolution on stable carbon isotope of drip is not the same among different drip points of the cave The main reason for the great difference is that the occurrence of pre-calcite deposition (PCP) process is the dominant factor in the drifting water δ13CDIC in the path of water transport.In addition, this study also found that 1 # and 4 # drip corresponding secondary chemical sediments The characteristics of 87Sr / 86Sr ratio mainly reflect the relative contribution of overlying soil system (soil water) to bedrock dissolution. It is feasible to characterize the weathering intensity and its change of overlying soils based on 87Sr / 86Sr index of secondary cave sediments in the local caves. Monsoon climate information in the region.