Application of artificial thermoluminescence of feldspar to geothermal resource exploration technology

2021 Fiscal Year Final Research Report

• Project/Area Number: 19K05344
• Research Category: Grant-in-Aid for Scientific Research (C)
• Allocation Type: Multi-year Fund
• Section: 一般
• Review Section: Basic Section 31020:Earth resource engineering, Energy sciences-related
• Research Institution: Tohoku University
• Principal Investigator: HIRANO NOBUO 東北大学, 環境科学研究科, 助教 (80344688)
• Project Period (FY): 2019-04-01 – 2022-03-31
• Keywords: 長石熱発光 / Thermoluminescence / Feldspar / 地熱探査 / エルサルバドル

Outline of Final Research Achievements

The thermoluminescence behavior of feldspar NTL (natural TL) and ATL (artificially irradiated TL) was investigated. Compared to quartz, which is usually used in geothermal signature surveys, the geothermal effects of feldspar NTL were detected to some extent, although the effects were weak. The feldspar ATLs were able to detect the geothermal effects more clearly. As a result, it was concluded that geothermal signatures can be detected using feldspar, although the accuracy is inferior to that of quartz.
Finally, We estimated the center of geothermal signature using feldspar in the Ahuachapn geothermal field in El Salvador, Central America, and obtained results consistent with the locations of existing geothermal power plants and volcanoes.

Free Research Field

地球化学

Academic Significance and Societal Importance of the Research Achievements

石英TLを用いた地熱兆候探査はほぼ実用化されてきたが，当然ながら石英を産出しない場所では適用できない．しかし，長石についても石英と同様に地熱兆候探査に使用できることが判明したことから，この調査を適用できる地域を拡げることができた．また，この探査方法は他の地熱探査と比較して探査コストが非常に低いことから，本格的かつ高額な地熱探査をおこなう前に探査地域を絞り込むためのスクリーニング方法として非常に有効であるいえる．