The melting curves of the alkali chlorides and the sodium halides have been determined at high pressures. The results can be represented within experimental error by Simon's equation. Comparison of the slope of the melting curve at low pressure with measurements of the changes of volume and entropy upon fusion suggests that the latter data are systematically in error.
Research Article| August 01, 1956 EFFECT OF RADIATIVE TRANSFER ON TEMPERATURES IN THE EARTH SYDNEY P CLARK, JR. SYDNEY P CLARK, JR. DUNBAR LABORATORY, HARVARD UNIVERSITY, CAMBRIDGE, MASS. Search for other works by this author on: GSW Google Scholar Author and Article Information SYDNEY P CLARK, JR. DUNBAR LABORATORY, HARVARD UNIVERSITY, CAMBRIDGE, MASS. Publisher: Geological Society of America Received: 18 May 1956 First Online: 02 Mar 2017 Online ISSN: 1943-2674 Print ISSN: 0016-7606 Copyright 1956, The Geological Society of America, Inc. Copyright is not claimed on any material prepared by U.S. government employees within the scope of their employment. GSA Bulletin (1956) 67 (8): 1123–1124. https://doi.org/10.1130/0016-7606(1956)67[1123:EORTOT]2.0.CO;2 Article history Received: 18 May 1956 First Online: 02 Mar 2017 Cite View This Citation Add to Citation Manager Share Icon Share Facebook Twitter LinkedIn Email Permissions Search Site Citation SYDNEY P CLARK; EFFECT OF RADIATIVE TRANSFER ON TEMPERATURES IN THE EARTH. GSA Bulletin 1956;; 67 (8): 1123–1124. doi: https://doi.org/10.1130/0016-7606(1956)67[1123:EORTOT]2.0.CO;2 Download citation file: Ris (Zotero) Refmanager EasyBib Bookends Mendeley Papers EndNote RefWorks BibTex toolbar search Search Dropdown Menu toolbar search search input Search input auto suggest filter your search All ContentBy SocietyGSA Bulletin Search Advanced Search Abstract No abstract available. This content is PDF only. Please click on the PDF icon to access. First Page Preview Close Modal You do not have access to this content, please speak to your institutional administrator if you feel you should have access.
Geochemical data show that radioactive heat production in the crust plus upper mantle (which is defined seismically to terminate at a depth of 415 km) cannot account for the heat escaping from the Earth. Deeper sources must be invoked, and a number of qualitative models of the variation of radioactive heat generation with depth are suggested. Preferred models involve a narrow zone of high heat production about halfway between the crust and the core.
Data on underground temperature obtained during the construction of the Arlberg and Tauern tunnels in Austria have been combined with measurements of the thermal conductivity of 42 samples of rock from near the tunnels to calculate the terrestrial heat flow. The value in the Arlberg is found to be (1.9 ± 0.2) × 10−6 cal/cm2s, and in the Tauern, (1.8 ± 0.2) × 10−6 cal/cm2s. The new results are in good agreement with the value 1.9 × 10−6 cal/cm2 s found earlier in the Loetschberg tunnel in Switzerland, and indicate that relatively high geothermal fluxes extend into the eastern Alps. The high flux can be attributed to radioactive heat generation in a thickened crust.
A paper by Anderson [1967] on thermal expansion at high pressure has been discussed by Birch [1968] within the framework of equations of state with certain general functional forms. This note points out that certain simplifying assumptions have rather extensive consequences that include specifying a particular equation of state. It is neither necessary nor possible to make an independent assumption about the equation of state. Because of these consequences it is all too easy to reason in a circle and to make redundant or incompatible assumptions; these dangers must be emphasized.
The equilibrium curve between kyanite and sillimanite has been established by quenching experiments at temperatures between 1000 degrees C. and 1500 degrees C. and pressures between 17 and 24 kilobars. The curve is given by the expression P = 4.1 + 13.2 X 10 (super -3) T, where the pressure P, is in kilobars and the temperature, T, is in degrees Centigrade. There is some evidence that the phase boundary may depart from linearity at low temperatures, but no quantitative estimate of the amount of curvature can be obtained from present data. If kyanite forms stably in nature, pressures of nearly 10 kilobars are required. This is equivalent to the weight of about 30 km. of overburden. Such great depths of burial are not required if pressure is contained by the strength as well as by the weight of the overlying rock. It is suggested that "tectonic overpressures" of a kilobar or more may exist in rocks which are undergoing deformation.
Compressional and shear wave velocities (Vp and Vs) have been measured to 10 kbar in 17 granulite facies rocks and 15 eclogites. The former included quartzo-feldspathic, gabbroic, and garnet granulites as well as mangerites from the Adirondack region. The eclogites included the three types described by Coleman et al. from California, Norway, South Africa, and Tasmania. The mean ranges of the values of (∂Vp/∂P)T and (∂Vs/∂P)T in the 8- to 10-kbar range are slightly higher (0.015–0.022 and 0.008–0.012 km/s kbar) for eclogites than for granulites. Velocity-density systematics, based on the 10-kbar data, is evaluated in the light of Birch's law, D. L. Anderson's seismic equation of state, Wang's C-ρ relation, and the K-V relationship of O. L. Anderson and Nafe and D. L. Anderson and O. L. Anderson. On close analysis, there is a distinction in Wang's relations for ∼ 21 and ∼ 22. Most of the granulites and eclogites have values of ∼22; Birch's relationship for these and previously studied basalts ( ∼ 22) is Vp = −1.85 + 2.87ρ, where r2 = 96%. For Vs the best fit of the data for granulites and eclogites ( ∼ 22) is Vs = −0.33 + 1.40ρ, where r2 = 88%. The best-fit equation for Vs that includes the calcium oxide effect in all the granulites and eclogites is Vs = −0.63 + 0.21(21 − ) + 1.56ρ + 0.016 [CaO]. On the basis of the laboratory results, it is shown that elastic properties of garnet granulite with ∼ 22 are compatible with those of the 7.1- to 7.8-km/s crustal layer. Analysis of crust-mantle seismic data in various regions, and the present laboratory results, shows that the assumption of ∼ 22 for the lower crust as well as for the upper mantle fits better than ∼ 21. On the other hand, the ∼ 21 model fits better for some geophysically anomalous regions in the western United States.
The material in this section has been condensed from a more extensive summary which Dr. Kracek completed shortly before his death in 1960. Most of the data which have been omitted dealt with elements which are of little geologic interest, although in a few cases systems were discarded because it was believed that the results were of insufficient reliability or because conditions such as partial pressure of oxygen were unspecified. Certain binary systems, for example Al2 O3 –MgO, have not been included as such because all available information is given in the figure showing liquidus relations in a...
