| Abstrakt: |
Rock thermal conductivity is an essential parameter for the determination of heat flow of the Earth and geothermal modelling studies. It has important applications in hydrocarbon exploration, geothermal energy and geo-engineering investigations. We report thermal conductivity measurements of 55 core samples of Deccan flood basalt recovered from four boreholes KBH-1, KBH-5, KBH-6 and KBH-7 drilled in Koyna–Warna region of the western Deccan Volcanic Province (DVP). The cores represent a substantial thickness of the deep, unexposed sections of the Deccan basalt formation and allow sampling of the full spectrum of the compositional variations in the lava flows starting from the earliest flows in the region. We compare the data with those reported earlier from other parts of the DVP as well as with other continental flood basalt provinces worldwide. The salient results are as follows. (1) Thermal conductivity of flood basalts from the Koyna–Warna region fall in a relatively narrow range 1.29–1.87 Wm−1K−1 with a mean of 1.61±0.13 (SD) Wm−1K−1. When compared with massive basalt, the vesicular/amygdaloidal basalt samples show larger variability, likely due to the varying degrees of vesicularity and the composition of the secondary mineral fillings. (2) Thermal conductivity data obtained on a 1251-m long basalt core comprising 40 simple flows and 6 compound flows in the borehole KBH-7 yield a similar narrow range of 1.3–1.7 Wm−1K−1 and do not show any systematic trend with depth. (3) The conductivity range for basalts of the Koyna–Warna region is consistent with those reported previously from the northern, eastern and southeastern parts of the DVP including the Wardha–Yavatmal, Killari and Pune–Ahmednagar areas that expose basalt flows from different elevations and stratigraphic units. (4) The mean values of thermal conductivity of continental flood basalts from other flood basalt provinces worldwide such as Snake River Plain, Columbia River, Parana and Karoo are comparable to Deccan flood basalts. Research Highlights: Thermal conductivity of Deccan flood basalts from Koyna region varies in a relatively narrow range 1.29–1.87 Wm-1K-1 with a mean of 1.61±0.13 (SD) Wm-1K-1. Thermal conductivity data obtained on a 1251 m long, vertical, continuous basalt core do not show a systematic trend with depth. The data is consistent with those reported previously from other parts of Deccan Traps. Thermal conductivity data from continental flood basalt provinces worldwide including Columbia River, Parana, Karoo and Deccan Traps are comparable. [ABSTRACT FROM AUTHOR] |
