The Chingshui geothermal field once hosted the first geothermal power plant in Taiwan from 1981 to 1993. After a long period of inactivity, this field is attracting renewed interest to meet the need for clean energy. A 213-m length of cores (IC-21) with continuous recovery, the longest in the Chingshui geothermal field, was recovered from 600 m to 813 m below the surface in 2010. Three types of calcite crystal morphologies have been identified in the veins of the cores of well IC-21: bladed, rhombic and massive crystals. Bladed calcites are generated via degassing under boiling conditions with a precipitation temperature of similar to 165 degrees C and calculated delta O-18 value of -6.8 parts per thousand to -10.2 parts per thousand VSMOW for the thermal water. Rhombic calcites grow in low concentration Ca2+ and CO32- meteoric fluids and precipitate at approximately similar to 180 degrees C. Finally, massive calcites are characterized by co-precipitation with quartz in the mixing zone between meteoric water and magmatic or metamorphic fluids with calculated delta O-18 value of up to 1.5 +/- 0.7 parts per thousand VSMOW. Furthermore, the scaling and hot fluids at a nearby pilot geothermal power plant confirm a meteoric origin. Based on these observations, we propose that the current orientations of the main conduits for geothermal fluids are oriented at N10 degrees E with a dip of 70 degrees E. This result provides the basic information needed for deploying production and injection wells in future developments of the geothermal power plant in this region.