| Popis: |
Granitoid nmgmatism in East-Central Asia Granitoid magmatism has occurred on a vast scale in Transbaikalia, East Central Asia during the Phanerozoic. Within this huge and geologically complex region, many hundreds of individual plutons of syenite, quartz syenite, and K-rich granite have been intruded within NE-SW-oriented belts 200-400 km wide and 2000-3000 km long. These belts are superimposed upon and cut across more ancient tectonic structures (including basement blocks of different age and composition). The intrusive activity was accompanied by extrusion of the volcanic counterparts of these magmas. The composition of intrusive and extrusive magmas was absolutely independent of local country-rock composition (Leontiev eta/., 1981; Zanvilevich et a/., 1985; Litvinovsky et al., 1993.) Five main stages of intrusive activity are distinguished (see Table 1), and each suite of |
