PROBLEMS OF THE EARTH GRANITE LAYER FORMATION (MASS GRANITE FORMATION) BASED ON SEISMIC TOMOGRAPHY

• Дата: 2017
• Автор: Shevchuk, V.V.
• Формат: Стаття
• Мова: Ukrainian
• Опубліковано: Institute of Geological Sciences, NAS of Ukraine 2017
• Теми: granite formation; tectonosphere; seismic tomography; fluid magmatic systems; гранитообразование; тектоносфера; сейсмотомография; флюидно-магматические системы; гранітоутворення; сейсмотомографія; флюїдно-магматичні системи; 551.3
• Онлайн доступ: http://geojournal.igs-nas.org.ua/article/view/108248
• Назва журналу: Geological journal

 Complex problem of granite layer formation of the Earth reflects some extent global evolution of the planet, its substantial differentiation, formation of core, lithosphere and outer shells. Increasingly perfect seismotomographic investigations essentially concretizing structure of deep geospheres and visualizing connections between it, give new impulses for search of new solutions for a range of age-old challenges, in particular “challenge of granites”. Evolution analysis of ideas about granite deposits and formation of granite layer, which was formed both within geosynclinal platform and plate tectonic concepts on a new seismotomographic basis allows to distinguish two relatively independent fluid magmatic systems of various levels: basaltoid (tectonospheric) and granitoid (mantle to the core and tectonospheric) and to propose a model scheme for formation and development of hypothetic granitoid fluid magmatic system to a significant extent. The model foresees formation of thermo-fluid conglomerations critical in scale and pressures on the edge core-mantle, with stable silicon alkaline chemical specialization – the result of differentiation in the rear medium and its consecutive penetration to the upper levels of the planet, where formation of quartzo-feldspathic mineral associations (granite formation) is possible due to the appropriate RT-conditions. Geographical ranges of granite formation at the upper crustal level are determined not with separate tectonic modes or geodynamical atmospheres but scales of deep thermofluid anomalies which are indirectly connected with formation of tectonospheric basaltoid fluid magmatic systems and transformed with crustal structures. Granite is formed by granitizing fluid interaction with basaltoid melts of different generation levels and with solid upper crustal substrate of different age and origin. In this way metamagmatic, hybrid, diverse in composition, with prevailing porphyro-granitic sometimes rapakivi granites, whereof bodies have signs of allochthonic deposits, and autochthonous palingenic and metasomatic migmatites and granitoids, whereof establishing is accompanied with specific crustal tectogenesis. Discrete processes of mass granite formation can be partially combined with tectonospheric basaltoid fluid magmatic systems having predominantly permanent development.