Heat and mass transfer from the mantle: heat flow and He-isotope constraints
| Autor: | Boris G. Polyak |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2005 |
| Předmět: |
Isotope
business.industry Geothermal energy lcsh:QC801-809 Crust Geophysics lcsh:QC851-999 heat flow Mantle (geology) helium isotope ratio lcsh:Geophysics. Cosmic physics Heat flux Mass transfer Heat transfer geothermal energy mass transfer lcsh:Meteorology. Climatology business Geology Earth's internal heat budget |
| Zdroj: | Annals of Geophysics, Vol 48, Iss 1 (2005) |
| ISSN: | 1593-5213 |
| Popis: | Terrestrial heat flow density, q, is inversely correlated with the age, t, of tectono-magmatic activity in the Earth's crust (Polyak and Smirnov, 1966; etc.). «Heat flow-age dependence» indicates unknown temporal heat sources in the interior considered a priori as the mantle-derived diapirs. The validity of this hypothesis is demonstrated by studying the helium isotope ratio, 3He/4He = R, in subsurface fluids. This study discovered the positive correlation between the regionally averaged (background) estimations of R- and q-values (Polyak et al., 1979a). Such a correlation manifests itself in both pan-regional scales (Norhtern Eurasia) and separate regions, e.g., Japan (Sano et al., 1982), Eger Graben (Polyak et al., 1985) Eastern China rifts (Du, 1992), Southern Italy (Italiano et al., 2000), and elsewhere. The R-q relation indicates a coupled heat and mass transfer from the mantle into the crust. From considerations of heat-mass budget this transfer can be provided by the flux consisting of silicate matter rather than He or other volatiles. This conclusion is confirmed by the correlation between 3He/ 4He and 87Sr/86Sr ratios in the products of the volcanic and hydrothermal activity in Italy (Polyak et al., 1979b; Parello et al., 2000) and other places. Migration of any substance through geotemperature field transports thermal energy accumulated within this substance, i.e. represents heat and mass transfer. Therefore, only the coupled analysis of both material and energy aspects of this transfer makes it possible to characterise the process adequately and to decipher an origin of terrestrial heat flow observed in upper parts of the earth crust. An attempt of such kind is made in this paper. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|