| Title | Chronology of Volcamic and Hydrothermal Events in the Alto Peak Geothermal Field Based on Thermoluminescence Dating |
|---|---|
| Authors | Isao Takashima, Francisco G. Delfin Jr and Fernando R. Santos |
| Year | 1996 |
| Conference | PNOC-EDC Geothermal Conference |
| Keywords | |
| Abstract | Ages of 5 volcanic rocks and 5 altered materials are obtained by the thermoluminescence (TL) method for the Alto Peak geothermal area. The age range for volcanic rocks is 20ka to82ka, and that for altered materials is 2.7ka to 65k.a. These ages denote that both volcanic activities and hydrothermal events continue to Late Pleistocene to Recent. One fault cuts 82ka lava proves its movement after such age. It is also suggested that some volcanic formations must be re-check because the ages are not match to expected geologic column. If the cosmic ray contributes fully to the samples, possible TL age shifc to younger age side is 34% for the sample with the lowest radiogenic contents and 88 for that with the highest contents. Such figures reducing to 19% and 4% if I 10m erosion was expected from deposition to present sampling time. |