GSV TR2015/3 - Thermal conductivity measurements of Victorian rocks
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Product description:Executive SummaryHeat flow (Q) within the earth’s crust is expressed through Fourier’s Law and estimated from the product (multiplication) of the geothermal gradient (T) and thermal conductivity of the host rocks (K). This report presents thermal conductivity measurements from 526 rock samples (mainly drill core but some hand samples) that were directly collected by the Geological Survey of Victoria or compiled from exploration companies and university research. The bulk of the actual measurements were done under contract in the laboratory of Hot Dry Rocks Pty Ltd. The measured rocks cover many of the major rock packages in Victoria, both from the compacted and relatively conductive quartz rich bedrock and also from the more porous and generally more insulating mud and carbonate rich lithologies of the Gippsland, Otway and Murray Basins. Some bedrock sandstones and greywackes had unusually high thermal conductivity values (4.4 – 5.5 W/mK) but most yielded more moderate values (3 – 4 W/mK). The wide variety of igneous rocks in the bedrock, ranging from basalt through andesite to granite, had similar values (3 – 3.8 W/mK). The oldest, most compacted basin rocks and those richer in quartz attained values approaching the bedrock range (2.5 – 3.7 W/mK) whilst the thick volcanolithic packages of the Cretaceous rift fill sequences had more moderate values (2 – 2.5 W/mK). Many of the younger basin rocks have relatively low thermal conductivity values (1.0 – 1.5 W/mK) because of very high porosity and a lack of quartz. The thermal conductivity measurement process involved water saturation of the samples so that for many samples an estimate of the porosity and density was also obtained. Several trials showed success in combining this new point data with borehole geophysical logs, to give estimates of the thermal conductivity throughout the entire length of the drill holes being sampled so that a better understanding of the total distribution of rock thermal conductivity could be gauged. Download TR2015-3 Thermal conductivity measurements of Victorian rocks. (PDF 1.5MB) Bibliographic Reference Antriasian, A., Taylor, D., Mather, B., Harrison, B. & Sandiford, D., 2015. Thermal conductivity measurements of Victorian rocks. Geological Survey of Victoria Technical Record 2015/3. Related products:
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