Helium and Argon Isotope Abundances in Rocks of Lavozero Alkaline Massif |
| |
| Authors: | V A Nivin I L Kamensky I N Tolstikhin |
| |
| Institution: | 1. Geological Institute, Kola Science Centre of the Russian Academy of Sciences , Apatity, Russia;2. Geological Institute, Kola Science Centre of the Russian Academy of Sciences , 184200 Apatity, ul., Fersman, 14, Russia;3. Geological Institute, Kola Science Centre of the Russian Academy of Sciences , Apatity, Russia |
| |
| Abstract: | Abstract He and Ar isotope abundances in alkaline rocks of the Lovozero layered ore-bearing complex are used to discuss the origin of hydrogen-hydrocarbon gases (HHG). Three procedures to extract - crushing, milling and melting - and the chemical analysis of these gases have been described, and then the isotope analysis of the ratios of 3He/4He and 40Ar/36Ar is related. It is suggested, that (4He/40Ar)rad ratios and 4He concentrations decrease and 3He/4He increase with the distance from the ore zone, the former ratio being the most contrast indicator of ore mineralization. A direct correlation has been revealed between helium isotopic ratios and methane concentrations. The results of measurements confirm the idea on the crustal origin of HHG. |
| |
| Keywords: | Alkaline rocks argon isotopes helium isotopes isotope geochemistry |
|
|
