Abstract

The karst hydrogeology systems of the Watuputih Hills region of Central Java, Indonesia, have many springs with varying discharge and are composed of formations with complex geological structures. This work characterized the karst hydrogeology by studying 50 hydrogeological features (caves, springs and wells) and by analyzing the chemical-physical properties of groundwater in the field (pH, temperature, EC, HCO₃⁻, ²²²Rn) and the major ions and stable isotopes of the groundwater samples in the laboratory, along with the stable isotope content of rainwater sampled over 1 year. Hierarchical cluster analysis of the water samples identified three hydrochemical groups: groundwater flowing through carbonate rocks (groups C2 and C3), through quartz sandstones and volcanic rocks (group C4), and through carbonate rocks and the siliciclastic rocks (quartz sandstones) underneath them (group C1). Springs with large discharge, typified as artesian fault-guided springs, were categorized into group C1. These springs are Sumbersemen, Brubulan Tahunan, and Brubulan Pesucen, with mean discharges of 1,516, 165, and 95 L/s, respectively. Based on the results of the stable isotope analysis, the d-excess calculation and the ²²²Rn concentrations, groups C2, C3, and C4 associate with shallow groundwater systems that dominantly flow through pores, whereas group C1 associates with a deep groundwater system controlled by geological structure. The geological structure also determines the groundwater flow in the cave streams. The shallow groundwater system is sourced by local rainwater, while the deep groundwater system displays a relationship with the groundwater in the northern hills at an elevation >375 m above sea level.

中文翻译：

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水化学和环境同位素分析，以表征印度尼西亚中爪哇省Rembang Watuputih地区的复杂岩溶水文地质系统

摘要

印度尼西亚中爪哇省Watuputih Hills地区的岩溶水文地质系统有许多泉水，其出水量各不相同，并且由具有复杂地质构造的地层组成。这项工作通过研究50个水文地质特征（洞穴，弹簧和孔），并通过在该领域分析地下水的化学-物理性质（pH，温度，EC，HCO特征喀斯特水文₃ ^- ，²²²Rn）和实验室地下水样品中的主要离子和稳定同位素，以及在1年内采样的雨水的稳定同位素含量。水样的分层聚类分析确定了三个水化学组：地下水流经碳酸盐岩（C2和C3组），石英砂岩和火山岩（C4组）以及流经其下方的碳酸盐岩和硅质碎屑岩（石英砂岩）（ C1组）。具有大流量的弹簧（典型为自流断层引导弹簧）被分类为C1组。这些泉水是Sumbersemen，Brubulan Tahunan和Brubulan Pesucen，平均流量分别为1,516、165和95 L / s。根据稳定同位素分析的结果，d过量计算和²²²Rn浓度，C2，C3和C4组与主要流经孔隙的浅层地下水系统相关，而C1组与受地质结构控制的深层地下水系统相关。地质结构还决定了洞穴溪流中的地下水流量。浅层地下水系统是由当地雨水提供的，而深层地下水系统则与海拔高于375 m的北部丘陵地区的地下水有关系。