This study investigates the geochemistry and isotopic characteristics of geothermal manifestations in the Way Ratai geothermal field, Lampung, Indonesia, to elucidate the system's fluid flow, reservoir temperature, and the origins of its thermal waters. Fourteen samples were collected from Way Ratai, with three additional from Jatimulyo and four from Natar. The major ion contents and stable isotope ratios (O and ) were examined. The Way Ratai hot springs are classified as chloride-type waters based on the Cl-SO-HCO concentration ratios, whereas the Natar and Jatimulyo hot springs are characterized as bicarbonate-type waters. The estimated reservoir temperature for the Way Ratai system ranges from approximately 174 °C to 210 °C, with a depth between 600 and 1000 m. Isotopic analysis indicates that the thermal waters at Way Ratai predominantly originate from meteoric sources. The recharge area for the Way Ratai geothermal fluid is estimated to be at an elevation of 1200 m above sea level, corresponding precisely to the location of Mt. Ratai. Through geochemical and isotopic analysis, it is inferred that the hot springs at Natar and Jatimulyo are connected to the Way Ratai reservoir, having undergone mixing and dilution processes. This research is integral to effective exploration and development strategies in the region, offering key insights into the potential of the Way Ratai geothermal field. The detailed geochemical and isotopic analyses contribute to a deeper understanding of the geothermal systems in the area and their viability for sustainable energy exploitation.

中文翻译：

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解密 Way Ratai 地热系统，印度尼西亚楠榜：综合地球化学和同位素分析

本研究调查了印度尼西亚楠榜 Way Ratai 地热田的地热表现的地球化学和同位素特征，以阐明该系统的流体流动、储层温度及其热水的起源。从 Way Ratai 采集了 14 个样本，另外 3 个样本从 Jatimulyo 采集，4 个样本从 Natar 采集。检查了主要离子含量和稳定同位素比（O 和 ）。根据 Cl-SO-HCO 浓度比，Way Ratai 温泉被归类为氯化物型水，而 Natar 和 Jatimulyo 温泉则被归类为碳酸氢盐型水。Way Ratai 系统的估计储层温度范围约为 174 °C 至 210 °C，深度在 600 至 1000 m 之间。同位素分析表明，Way Ratai 的温泉水主要来自大气源。Way Ratai地热流体的补给区估计海拔1200米，与Ratai山的位置精确对应。通过地球化学和同位素分析，推断Natar和Jatimulyo的温泉与Way Ratai水库相连，经历了混合和稀释过程。这项研究是该地区有效勘探和开发战略的组成部分，为了解 Way Ratai 地热田的潜力提供了重要见解。详细的地球化学和同位素分析有助于更深入地了解该地区的地热系统及其可持续能源开发的可行性。