Fingerprinting sediment sources in a typical karst catchment of southwest China
Fingerprinting sediment sources in a typical karst catchment of southwest China
复制标题
中国西南典型岩溶流域沉积物来源指纹图谱
DOI：
10.1016/j.iswcr.2020.06.005
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发表时间：
2020
影响因子：
6.4
通讯作者：
Kelin Wang
中科院分区：
文献类型：
--
作者：
Zhenwei Li;Xianli Xu;Yaohua Zhang;Kelin Wang
岩溶地区水文地质条件复杂，直接测量流域尺度的泥沙来源是困难的。研究目的是定量分析中国西南喀斯特流域泥沙来源的相对贡献及其时间变异性。岩溶洼地可以像水库、大坝一样截留侵蚀沉积物，是岩溶区沉积物来源识别的典型试验床。在岩溶洼地采集了3个沉积物柱样，采集了3个潜在沉积物来源的58个土壤样品，分析了18个土壤性质。利用多元混合模型计算了农田、林地和裂隙土的相对贡献。指纹结果表明，农田是喀斯特流域沉积物的主要来源。从3个沉积柱样的平均产沙率来看，农田表层土壤的产沙率为69.3%，变化范围为46.9%~ 92.3%，林地土壤和裂隙土的产沙率分别为8.6%和22.1%，变化范围为2.8%~ 16.5%和4.8%~ 36.6%。这一结果表明，当仅使用单个岩心定量沉积物源时，应引起高度重视。由于岩溶洼地沉积物一般都曾被人为扰动过，因此，洼地内近几十年未被人为扰动的区域更适合作为岩溶流域泥沙来源的示踪区域。据我们所知，这项研究是第一次量化的贡献，在中国西南岩溶流域的沉积物来源。该研究为应用复合指纹技术定量岩溶流域沉积物来源提供了有价值的信息和初步参考。
Due to the complex hydrogeological conditions in karst regions, it is difficult to measure sediment source contributions at a catchment scale directly. The objective of this study was to quantify the relative contributions of sediment sources and their temporal variability in a karst catchment in southwest China. Karst depressions can trap eroded sediment similar to a dam or reservoir and, thus, are representative and typical test beds for identifying sediment sources in karst regions. Three sediment cores were taken from a karst depression, 58 soil samples from three potential sediment sources were collected, and 18 soil properties were analyzed. The relative contributions of cropland, forestland, and fissure or crack soils were calculated using a multivariate mixing model. The fingerprinting results demonstrated that the cropland was the main sediment source in karst catchment. Specifically, according to the mean sediment contributions of the three deposited sediment cores, the sediment contribution from cropland topsoil was 69.3%, varying from 46.9% to 92.3%, and forestland soil and crack soil accounted for 8.6% and 22.1% of the sediment yield, and varying from 2.8% to 16.5% and 4.8%–36.6%, respectively. This result indicated that great attention should be paid when using only a single core to quantify sediment provenance. Due to the deposited sediment was generally disturbed as cropland in the karst depression, the area that has not been disturbed in recent decades in depression was more appropriate to trace sediment sources in karst catchment. To the best of our knowledge, this study was the first to quantify the contributions of sediment sources in the karst catchment of southwest China. This study provides valuable information and a preliminary reference for applying a composite fingerprinting technique to quantify sediment sources in karst catchments.