本計畫將延續上一個計畫「安山岩區水文作用中地下水之水氧同位素研究(I)」，本年度的研究重點主要是評估不同岩性對水氧同位素的影響，並利用追蹤劑來探討地下水在不同岩性中的行為。近年來，地下水研究逐漸體認到地下水在未固結沉積物中的行為並不能完全適用於固結的岩層中。另一方面，台灣有將近百分之七十為固結岩石的山區，對其水文行為的了解更是不容忽視。本研究區域位於大屯火山群的大屯山和面天山前緣，本火山群最近有學者認為是個活火山而且位於大台北都會區附近，加上又有非常多著名的溫泉，因此吸引有許多的研究。但是比較少研究以地下水的水氧同位素來了解地下水在安山火山區之水文循環作用。本校正好位於大屯火山區內，加上本系已建置一套水氣氧同位素儀器（Picarro Isotopic Water Liquid Gas Analyzer L1102-i）以及新購四組地下水微量追蹤量測器(Temphion Submersible Smart pH/ISE/Redox Sensor),其中溴的解析度可達0.01ppm。我們希望透過密集量測地下水、溪水、以及泉水中之δ18O 與δD同位素並同時在井下施放追蹤劑來進一步瞭解地下水在安山岩區與沉積岩區的行為。我們選的場址岩層主要由火山熔岩與五指山層組成，範圍不大，岩層界面清楚，是一理想地點來測試不同基岩間的地下水行為。
There has been an increasing awareness that in many circumstances the theories associated with the description of hydrogeologic processes in granular porous media are unadoptable completely in the description of these same phenomena in fractured rock and geologic formations. This discrepancy phenomenon makes the research in hardrock hydrogeology so valuable than ever, particular in Taiwan. Most researches efforts have been done in unconsolidated media for the past 20 years in Taiwan. However, Taiwan is composed of more than 60% of mountain region, hard and consolidated rock, where is poorly understood in terms of hydrological and isotopic characteristics. Without any doubt, isotope investigation and tracer test in hardrock regions posts a great promising future, particular in headwater catchment regions, where the entire rainfall-runoff process starts in a catchment scale. We are proposing an interdisciplinary study in groundwater study by analyzing isotopes in surface and subsurface waters, conducting tracer test and chemical analysis in wells.We are well equipped and pose several advantages for proposing this project. First, we newly purchased 4 sets of tracer test equipment (TempHion Submersible Smart pH/ISE/Redox Sensor)with a well-function isotope analyzer for both liquid and gas phase( Picarro Isotopic Water Liquid Gas Analyzer L1102-I). This enables us to complete the study right in our department and to determine how the bedrock groundwater process in the study area. Secondly, we are located right in the Tatun Volcano Group(TVG); it allows us to sample effectively whenever it necessary. The site we proposed is composed of two different geologic units, lava flow and sedimentary rock unit, the Wuchihshan Formation. This would provide information how isotopic characteristics differently in two different rock units within a reasonable scale.
