The thermal properties, temperature structure and thermal evolution of the Eastern Ghats, India.

Andrew R. Barker, 2010. University of Adelaide. Unpublished Hons thesis, pp122.

Abstract: The role of the portable gamma ray spectrometer has become a fundamental addition for gathering heat production data for coinciding stochastic thermal modelling of the crust. Numerous sensitivity and calibration analyses have been undertaken to verify the validity of the output, and to aid in more efficient and effective use for future users. When applied to a heat flow study of the Eastern Ghats, it was established that the predominantly granulite-facies rocks such as khondalites, K-feldspar megacrystic granites and quartzo-feldspathic gneisses have high average heat production values of 3.76 ±0.53 μW/m³, 2.79 ±0.53 μW/m³ and 5.49 ±0.69 μW/m³ respectively, whereas the ultra-high temperature (UHT) granulites have a low heat production of 0.69 ±0.23 μW/m³. The contribution of uranium to the total heat production was considered low when compared to the input from thorium, which is almost four times higher. The average concentrations of thorium were also approximately fifteen times more than the concentrations of uranium. In this research, thermal conductivity testing was conducted to better constrain parameters for stochastic thermal modelling. Coupled with previous seismic studies, four crustal sections were analysed by one-dimensional steady-state finite difference models using the results of this project. Conclusions drawn from this study indicate that there is a possibility the Eastern Ghats is currently a UHT region, whereas there is little doubt that burial of the near surface high heat producting rocks to mid-crustal levels could have produced the observed 900 Ma UHT granulite-facies metamorphism in the Eastern Ghats.