| Title | Temperature Gradient Hole Results from Makushin Geothermal Area, Unalaska Island, Alaska |
|---|---|
| Authors | Isselhardt, C. F.; Matlick, J. S.; Parmentier, P. P.; Bamford, R. W. |
| Year | 1983 |
| Conference | Geothermal Resources Council Transactions |
| Keywords | Exploration; USA; Alaska; Unalaska; Temperature Gradient; Logs |
| Abstract | Following geological, geophysical and geochemical surveys of the Makushin geothermal area, there 15,00 foot temperature gradient holes (TGH) were sited and drilled. TGH D-1 penetrated adnesites and diorite, locally hydrothermally altered, and yielded both convective and conductive thermal profiles. TGH E-1 exhibited high temperatures (195°C) and corresponding geochemical indicia. TGH I-1 was cool (-80°C) but showed geochemistry indicative of a paleogoethermal environment. The high thermal gradients (145°C to 692°C/km) temperatures (195°C), and geochemistry provide strong evidence for the existence of a shallow, high temperature geothermal system. |