Radioactive heat generation and heat flow in the Indian shield

Using a laboratory gamma-ray spectrometer, 160 rock samples from different heat flow sites in India have been analysed for their U, Th and K contents. Heat generation has been estimated for the significant rock types. Of the six regions covered by this study, correction due to heat generation contrast and geologic structure was found necessary and has been applied in two regions. Heat flow/heat generation plots for two regions in the southernmost part of the shield follow the line characteristic of a normal continental heat flow province. The plots for the other four regions indicate a heat flow province with an intercept of 0.92 HFU and a slope of 14.8 km. From data available at present, these parameters are higher compared to those from the other shields. The higher parameters imply a higher temperature and heat flow at the Moho, indicating a region of “hotter” upper mantle in the Indian shield.