HR: 0800h
AN: T11B-0576    [Abstracts]
TI: Thermal Properties of Granite from Korea
AU: * Kim, J
EM: geotherm01@gmail.com
AF: Kongju National University, 182 Shinkwan-dong, Kongju, 314-701, Korea, Republic of
AU: Lee, Y
EM: ymlee@kigam.re.kr
AF: Korea Institute of Geoscience & Mineral Resources, 30 Gajeong-dong, Yuseong-gu, Daejeon, 305-350, Korea, Republic of
AU: Koo, M
EM: Koo@kongju.ac.kr
AF: Kongju National University, 182 Shinkwan-dong, Kongju, 314-701, Korea, Republic of
AB: Thermal and physical properties were measured on 206 Jurassic granite samples obtained from three boreholes in the central part of Korea. Thermal conductivity (λ), thermal diffusivity (α), and specific heat (C_p) were measured in a laboratory; the average values are λ=2.813 W/mK (1.962- 3.867 W/mK), α=1.296 mm²/sec (0.93-1.787 mm²/sec), C_p=0.816 J/gK (0.750-0.877 J/gK), respectively. In addition, porosity (φ), and dry and saturated density(ρ) were measured; the average values are φ =0.01 (0.002-0.041), ρ (dry)=2.662 g/cm³ (2.540-2.760 g/cm³), and ρ (saturated)=2.67 g/cm³ (2.547-2.771 g/cm³), respectively. Experimental data show that thermal conductivity increases with increasing thermal diffusivity and decreases with increasing porosity. However, thermal conductivity does not show good correlation with density.
Thermal diffusivities of 10 granite samples were measured with increasing temperature from 25° C to 200° C. In this study, we found that thermal diffusivity at 200° C is about 30% lower than thermal diffusivity at 25° C.
Using mixing law models, thermal conductivity of a rock sample can be estimated from its mineral contents. The estimated average thermal conductivity values using a geometric and a square-root mean models are 3.685 W/mK and 4.030 W/mK with average relative errors of 22.7% and 33.9%, respectively. Granite samples mainly consist of quartz (~38 Vol%, 7.69 W/mK) and albite (~30 Vol%, 2.14 W/mK). Two main mineral compositions (quartz and albite) strongly influence thermal conductivity of granite. A linear equation including two main components was derived from multiple linear regression (λ=-0.014·V_Quartz- 0.047·V_Albite+5.0, where V is Vol%).
Specific gravities were measured on 10 granite samples in the laboratory. The measured specific gravity ranges from 2.603 to 2.669. The specific gravity depends on chemical compositions of granite. Therefore, specific gravity can be estimated by the felsic-mafic index (F) that is calculated from chemical contents. The estimated specific gravity ranges from 2.643 to 2.658. The average relative error between measured and estimated specific gravities is 0.677%.
DE: 5134 Thermal properties
DE: 5418 Heat flow
DE: 8130 Heat generation and transport
DE: 9320 Asia
DE: 9611 Jurassic
SC: Tectonophysics [T]
MN: 2007 Fall Meeting