A new method has been developed to measure thermal conductivity of monomineralic aggregate at ordinary temperature and pressure, in which the needle‐probe technique is applied to a mixture of powdered specimen and distilled water. By use of this method, thermal conductivity of 166 rock‐forming minerals has been determined. The results are discussed in relation to the density, crystal structure, and chemical composition of the minerals. The major conclusions are: (1) for most of the minerals, thermal conductivity is a linear function of density for constant mean atomic weight; (2) the conductivity of silicates is controlled by the structure of the silicon‐oxygen network and is lower for the more complicated networks; (3) in an isomorphous series (garnets, pyroxenes, amphiboles, and carbonates), the thermal conductivity decreases as the mean atomic weight, or the mass of metallic ions, increases; (4) in a series that forms a binary solid solution (olivine, pyroxene, and plagioclase), the conductivity has a minimum at an intermediate composition; (5) the thermal conductivity of silicates is related linearly to elastic‐wave velocities.

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Using a new temperature recording instrument recently developed at the Woods Hole Oceanographic Institution, downhole temperature measurements were made at five sites during Deep Sea Drilling Project Leg 86. The instrument, which can be installed in the shoe of the hydraulic piston corer, allows measurements of sediment temperature to be made simultaneously with the collection of sediment cores. A numerical procedure was applied to correct the temperature disturbance caused by the corer's friction with the sediment. Detailed temperature profiles constructed from the data were combined with the measurement of thermal conductivity to calculate heat flow. Heat flow values were generally low at all sites of Leg 86, consistent with the age of the lithosphere (> 100 m.y.) in the Northwestern Pacific Basin.

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A total of 1547 thermal conductivity values were determined by both the NP (needle probe method) and the QTM (quick thermal conductivity meter) on 1319 samples recovered during DSDP Leg 60. The NP method is primarily for the measurement of soft sedimentary samples, and the result is free from the effect of porewater evaporation. Measurement by the QTM method is faster and is applicable to all types of samples-namely, sediments (soft, semilithified, and lithified) and basement rocks. Data from the deep holes at Sites 453, 458, and 459 show that the thermal conductivity increases with depth, the rate of increase ranging from (0.18 mcal/cm s °C)/100 m at Site 459 to (0.72 mcal/cm s°C )/100 m at Site 456. A positive correlation between the sedimentary accumulation rate and the rate of thermal conductivity increase with depth indicates that both compaction and lithification are important factors. Drilled pillow basalts show nearly uniform thermal conductivity. At She 454 the thermal conductivity of one basaltic flow unit was higher near the center of the unit and lower toward the margin, reflecting variable vesicularity. Hydrothermally altered basalts at Site 456 showed higher thermal conductivity than fresh basalt because secondary calcite, quartz, and pyrite are generally more thermally conductive than fresh basalt. The average thermal conductivity in the top 50 meters of sediments correlates inversely with water depth because of dissolution of calcite, a mineral with high thermal conductivity, from the sediments as the water depth exceeds the lysocline and the carbonate compensation depth. Differences between the Mariana Trench data and the Mariana Basin and Trough data may reflect different abundances of terrigenous material in the sediment. There are remarkable correlations between thermal conductivity and other physical properties. The relationship between thermal conductivity and compressional wave velocity can be used to infer the ocean crustal thermal conductivity from the seismic velocity structure.

Robertson and Peck's data published in 1974 on the thermal conductivity of Hawaiian basalts are unique in the sense that the vesicularity of the samples used for the study covers a wide range of 2 to 98%. The data consist of the measurement results of thermal conductivity on 61 samples of basalt collected from Kilauea and other volcanoes in Hawaii. The thermal conductivity was measured, by the method of thermal stacking, on samples with their pores filled first with air and then with water. Thus the data are particularly suitable for evaluating the theoretical formula describing the thermal conductivity of fluid‐saturated porous rock. In the formula for the thermal conductivity of a two‐phase material the thermal conductivity of the solid matrix is an essential parameter, which Robertson and Peck determined by the wet cell method. The result of their determination was that they could not represent the data in the whole range of sample porosities with a single theoretical formula. This paper proposes that the thermal conductivity of the solid matrix can be estimated by extrapolating the data to zero porosity. For the extrapolation, either Fricke‐Zimmerman's or Schulz's formula of thermal conductivity for a two‐phase material having spheroidal inclusions can be used. In both models, for the results of extrapolation from the air‐saturated and the water‐saturated sample thermal conductivities to be identical, the spheroid's aspect ratio is assumed to be around 1/10. This is considered to be a combined effect of the spherical pores and the microcracks in the basalt samples. With the assumed aspect ratio of the spheroidal inclusions, either of the theoretical formulae agree with the data with sufficient precision.

The basic pattern of heat flow in the Bering Sea is revealed by 43 measurements obtained in the Aleutian, Kamchatka, and Bowers basins. Averages of the observed values are 55 mW m−2 in the Aleutian Basin, 120 mW m−2 in the Kamchatka Basin, and 80 mW m−2 for two measurements in the Bowers Basin near the Bowers Ridge. Correcting these averages for the effects of sedimentation gives values of 69 mW m−2, 138 mW m−2, and 95 mW m−2, respectively. A useful nomogram for computing the thermal effect of an extended period of sedimentation is presented. Several methods of averaging heat flow values in marginal basins are compared using the data from the Aleutian Basin. If the Aleutian Basin was formed by the sea floor spreading process, then the heat flow suggests an age of about 44 m.y., which is considerably younger than magnetic data suggest. An alternative explanation is that the high heat flow is a residuum of thermal processes associated with the now extinct Kula Spreading Center and the Kula Plate, which underthrust the Bering Sea in the early Tertiary and thermally rejuvenated the trapped Mesozoic sea floor underlying the Aleutian Basin. The high average heat flow in the Kamchatka Basin suggests a considerably younger age for this basin, and the very high values in the southwestern part indicate either thin lithosphere or recent magmatic activity.