Tectonic control of mafic intrusions in the Tastau volcanoplutonic complex (eastern Kazakhstan)
K.A. Dokukina a , V.G. Vladimirov b
a Geological Institute, Russian Academy of Sciences,7 Pyzhevsky per., Moscow, 119017, Russia
b Institute of Geology and Mineralogy, Siberian Branch of the RAS, 3 prosp. Akad. Koptyuga, Novosibirsk, 630090, Russia
Keywords: Melt injection; melt fragmentation; synkinematic magmatism; shear zone; peperite
Pages: 582-593
Abstract
We discovered unusual very small (2 to 70 cm) mafic bodies intruded into metamorphosed Early Carboniferous sandstone and shale in the Late Paleozoic Tastau volcanoplutonic complex (Char shear zone, eastern Kazakhstan). The small intrusions possibly emplaced during shearing when sediments experienced cataclasis and ensuing viscosity decrease. The shear rate was comparable to that in historic crustal earthquakes. Rapid shear motion concurrent with magmatism caused fragmentation of the injecting low-viscosity melt and its dispersal in globular and other bodies along linear breccia zones. The origin of the intrusions is explained in a tectonic model.
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