| Title | Reconstructing geothermal geological models by combining geophysical, geochemical and geological studies in Tatun volcanoes area, Northern Taiwan |
|---|---|
| Authors | Jian-Cheng Lee, Chien-Chih Chen, Hideaki Hase, Hsin-Hua Huang, Cheng-Horng Lin, Sheng-Rong Song |
| Year | 2026 |
| Conference | World Geothermal Congress |
| Keywords | |
| Abstract | In this study, we conduct a multi-disciplinary study, including geophysics, geochemistry, and geology, with previously drilled wells, to reconstruct geothermal geological models at the shallow 3-5 km in the Tatun volcano area, northern Taiwan. Our geological profiles show that the Tatun volcanoes have a ~1-2-km thick of lava and pyroclastic deposits, erupted on top of the 6-8-km-thick fold-and-thrust belt of Miocene sedimentary rocks. The seismic velocity imaging indicates a main magma reservoir of high anomaly of Vp at the depths of 8-15, with an estimated volume of ~250-300 km3. Incorporating the regional geology with the newly acquired magnetotelluric results, we found three high-resistive areas at different depths, which we tend to interpret as possible “heat bodies”, overlaid by low-resistive layers, which we interpreted as “cap rocks”: 1) two shallow reservoirs, at depth 600-1200 m (150-250°C), and 2) a deeper reservoir of ~ 2-3 km, in the uppermost basement of quartz-rich sandstone. At least four shallow high micro-seismicity zones have been observed. Two zones with cylinder shape are interpreted as conduits of hot fluid derived from deep over-pressured zones, beneath the Qixing Mt and Da-You-Keng (depth of 1~3 km). One zone is more dispersed beneath the Da-Jian-Hou shan at the depths of 1-4 km. The fourth zone occurred in the deeper part around the outer edge of the fluid saturated magma reservoir around 4-6 km depth. These hot-fluid related seismicity zones are considered of potential for “super-hot or super-critical geothermal” exploration. |