Physicochemical conditions of magma formation at the base of the Siberian plume: Insight from the investigation of melt inclusions in the meymechites and alkali picrites of the Maimecha-Kotui province |
| |
| Authors: | I D Ryabchikov L N Kogarko I P Solovova |
| |
| Institution: | (1) Institute of Geology of Ore Deposits, Petrography, Mineralogy, and Geochemistry (IGEM), Russian Academy of Sciences, Staromonetnyi per. 35, Moscow, 119017, Russia;(2) Vernadsky Institute of Geochemistry and Analytical Chemistry, Russian Academy of Sciences, ul. Kosygina 19, Moscow, 119975, Russia |
| |
| Abstract: | Based on the compositions of melt inclusions and coexisting minerals from meymechites and alkali picrites, the temperatures and pressures of the ascending material of the Siberian plume were estimated at the level of the lithosphere-asthenosphere boundary. The melts trapped in olivine show high contents of titanium and other incompatible elements. The rocks crystallized under high oxygen fugacity conditions. The calculated compositions of primary magmas are similar to the compositions of near-solidus melts derived from a dry fertile lherzolite at 7 GPa. The estimated potential temperature is close to 1650°C, which is much higher than the potential temperature of plumes that generate the primary basaltic magmas of mid-ocean ridges. The obtained data show that, during the activity of the giant magma-generating system of the Siberian trap province, hot peridotite masses ascended probably from the core-mantle boundary up to the base of the continental lithosphere. Our results are at odds with the suggestion that the basalt flows of the Siberian and other large igneous provinces are not related to mantle plumes. |
| |
| Keywords: | |
| 本文献已被 SpringerLink 等数据库收录！ |
|
