Reconstructing the thermal structure of shallow crust in the Tono region using multi-OSL-thermometry of K-feldspar from deep borehole core

Ogata, Manabu ; King, G. E.*; Herman, F.*; Sueoka, Shigeru   

Optically stimulated luminescence (OSL)-thermometry can be used to reconstruct the thermal structure in slowly denuded regions where infrared stimulated luminescence (IRSL) signals of samples obtained from deep boreholes are measured and evaluated with depth. Until now, only one study has explored this approach, using a target mineral of Na-feldspar. In this study, we applied multi-OSL-thermometry to K-feldspar obtained from deep borehole core samples (MIZ-1) drilled at the Tono region, central Japan, which is a well-documented thermally stable crustal environment. The inverted temperature for the IRSL 50 C of the samples at a depth of 1 km (40 C) were consistent with the in-situ temperature. The results suggest that the application of OSL-thermometry to K-feldspar in a borehole is useful to reconstruct the paleothermal condition.