雖然大多數地熱儲集層位於深處,在地表通常不會有明顯的徵兆表現,一般最常見是在地表以溫泉的形式顯現,因此熱水循環運動與路徑對地熱資源了解以及將來運用扮演了至關重要角色。一般來說,來自儲集層熱水資源透過深部區域流動系統或裂隙或斷層而形成,其特性是流動路徑長,速度極慢之地下水運動。在的熱區域範圍內,由於強烈的地質異質性,一般常規水文地質調查和數值計算岩石裂縫性含水層中熱水流動模型難以提供足夠的地熱水文地質描述。在這種情況下,利用地球化學演化與同位素分析來瞭解地熱地下水的補注源,流動路徑,可能混合,和水岩相互作用的資訊,可以提供進一步了解熱源機制和循環演化以及將來運用地熱資源基礎資訊,並可提供地熱地區次生礦物形成可能機制與分布的可能關聯,更是將來地熱電廠選址以及精準估算熱交換焓值的示蹤劑試驗之基礎,與電廠營運尾水回注的重要參數。。因為台灣地質年輕、抬升快速、裂隙發展發達,加上降雨豐沛、淺層入滲作用劇烈我們認為台灣山區地熱區域之熱水循環至少有兩個系統,淺層和深層而非由單一深層斷層單純循環帶到地表。長期以來地球化學都以有限的水體同位素了解地熱區域或山區之水源補注,非常可能得到不完整圖案而錯失不同頻率的循環。因此長時間且連續性的不同水體-包括河水、雨水、天然湧水、地下水-採集分析氫氧同位素與主要離子將有助於完整的了解一個區域水循環路徑,區分並確認地熱區域之主要熱水循環。我們將以土場與清水地熱區為研究區域,在清水溪、赤鹿坑溪、田古爾溪、土場溪上、中、下游採溪水與自然湧泉以及地熱井之井下地下水為取樣點以兩年來密集採樣分析驗證。無論結果如何,本計畫都將帶給台灣地熱研究領域極大的貢獻。
The most manifestation of geothermal reservoirs usually is hot springs on or near the surface. It is, therefore, crucial to identify the hot water circulations in the geothermal field before and after the implementation of a geothermal power plant. Usually, a few isotopes data were used to identify the recharge altitude to imply its circulations.It is too simplified to consider the circulation of a geothermal region of Taiwan in just one as Taiwan is a young and active geologic geothermal rich region with ample precipitation annually. In order to identify the shallow circulations from deep circulations in the geothermal regions, we need higher frequency sampling of waters from creeks, springs, and groundwaters to do the job. We are proposing a two-year project to sample waters regularly from upper, middle and lower creeks, hot springs and groundwater in the Chinshuei and Tuchen geothermal areas. All water samples will be analyzed in oxygen and hydrogen isotopes, major cations and anions to complete the project. This will be the first to conduct this lengthy and continue research in Taiwan in this particular purpose. The result from this project will bring tremendous impact on the water circulation of the geothermal reservoir region in Taiwan.