Analysis of Heat Flow Data--I Detailed Observations in a Single Borehole

Summary Heat flow data from a 600-m deep diamond drilled borehole has been used to estimate how short a section of borehole will give a valid heat flow value, to test for recent and ancient climatic changes, underground water-flows and the variation of terrestrial heat flow with depth. Temperatures were repeatedly measured at 3-m intervals; measurements of thermal conductivity, density and porosity were made on specimens sampled at approximately 4-m intervals along the length of the hole. The mean heat flow for the whole borehole before applying any corrections is 0.76 h.f.u. while after correcting for the Wisconsin glaciation the mean value is 1.17 h.f.u., but in both cases some 30 to 100-m sections of the borehole differ by ±20 per cent from the mean values. The differences cannot be entirely explained as being due to structure, topography, climatic changes or underground water-flows.