Su possibili stati termici della crosta granitica

Forni, Luigi

Atti della Accademia Nazionale dei Lincei. Classe di Scienze Fisiche, Matematiche e Naturali. Rendiconti, Tome 74 (1983), p. 396-404 / Harvested from Biblioteca Digitale Italiana di Matematica

Résumé

Possible thermal states of the granite crust. Apart from transient thermal regiments, the thermal state of the granite crust is solely determined by the flow from the upper mantle and the distribution of radiogenic sources (Birch et alii, 1968). In wiew of this premiss, a study was made of four actual thermal situations to determine both the development of radiogenic heat and that ascribable to the flow from the upper mantle. It was found that: a) the temperature increases caused by radiogenic sources was never more than 350 °C, which means that melting phenomena, if any solely determined by this factor can be ruled out; b) the sum of the two factors gives temperatures of more than 800 °C at depht of $15 \div 16$ km. It may realistically be supposed, therefore, that a temperature of this nature, which is higher the melting of granite, must by attributable to pockets of molten material in the middle and upper layers of the crust.

Détail

Publié le : 1983-06-01

Bibliographie

Beloussov, V.V. (1966) - Modern concepts of the structure and development of the Earth's crust and the upper mantle of continents, «Quart. Journ. Geol. Soc.», 122, 293-314.

Beloussov, V.V., Reisner, G.I., Rudich, E.M. e Sholpo, V.M. (1974) - Vertical movements of the Earth's crust on the continents, «Geophys. Surv.», 1, 245—273.

Birch, F., Roy, R.F. e Decker, E.R. (1968) - Heat flow and thermal history in New England and New York, chapter 33, in: «Studies in Appalachian Geology», eds. W.S. White e E-An Zen, Interscience, New York.

Carslaw, H.S. e Jaeger, J.C. (1959) - Conduction of heat in solids. 2a ed. Oxford Univ. Press. New York, 386 pp. | MR 22294 | Zbl 0029.37801

Forni, L. (in corso di stampa) - Evoluzione di anomalie geotermiche prodotte da masse rocciose calde, «Atti Acc. Sc. Torino».

Forni, L. e Malaroda, R. (1978) - A plume induced geothermic cycle and its gravimetric and isostatic effects; a mathematical model, «Boll. Soc. Geol. It.», 97, 739—748.

Goguel, J. (1975) - La Géothermie. Doin, Paris, 171 pp.

Kappelmeyer, O. e Haemel, R. (1974) - Geothermics with special reference to applications, «Geoexploratione Mon.», ser. 1, 4.

Lachenbruch, A.H. (1968) - Preliminary geothermal model of the Sierra Nevada, «Journ. Geophys. Res.», 73, 6977-6989.

Lachenbruch, A.H., Sass, J.H., Munroe, R.J. e Muses, T.H. (1976) - Geothermal setting and simple heat conduction model for the Long Valley Caldera, «Journ. Geoph. Res.», 81, 769-784.

Lovering, T.S. (1935) - Theory of heat conduction applied to geological problems, «Geol. Soc. Amer. Bull», 46, 69—94.

Malaroda, R. (1970) - Il granito: una roccia e molti problemi, «Boll. Ass. Min. Subalp.», Torino, 4, 621-674.

Mongelli, F. (1981) - Elementi di prospezione per l'energia geotermica. Adriatica Editrice, Bari, 150 pp.

Ramberg, H. (1967) - Gravity, deformation and the Earth’s crust. Academic Press, London e New York, 214 pp.

Roy, R.F., Blackwell, D.D., Decker, E.R. e Birch, F. (1968) - Heat generation of surface rocks and heat flow provinces, «Trans. Am. Geoph. Union.», 49, 319.

Sorgenfrei, Th. (1971) - On the granite problem and the similarity of salt and granite structure, «Geol. Foerem. Stockh. Foerh.», 93, 371-435.

Wedepohl K.H. ed. (1978) - Handbook of Geochemistry. Springer Berlin.

Winkler, H.G.F. (1976) - Petrogenesis of metamorphic rocks. Springer Berlin, 4a ed., 334 pp.

Willie, P.J. (1971) - The dinamic Earth. Wiley e Sons, New York, 416 pp.