The High Tatra granite intrusion is an example of a Variscan syn-tectonic, tongue-shaped intrusion. In some portions of the intrusion, structures occur which appear to be of sedimentary origin. These include structures similar to graded bedding, cross-bedding, troughs and flame structures, K-feldspar-rich cumulates and magmatic breccias. Formation of these structures might be related to changing magma properties, including crystal fraction, development of a crystal mush and a decrease in magma viscosity, stimulated by influx of mafic magma and high volatile content. The suggested processes in operation are: gravity-controlled separation, magma flow segregation, deposition on the magma-chamber floor, filter pressing and density currents stimulated by tectonic activity.%The formation of the sedimentary structures was also aided by the presence of large numbers of xenoliths that acted as a heat sink and influenced the thermal field in the intrusion, stimulating rapid cooling and crystal nucleation. Sinking xenoliths deformed the layering and, to some extent, protected the unconsolidated crystal mush from erosion by magma flowing past.%Areas with well-developed sedimentary magmatic structures can be viewed as having involved magma rich in crystals locally forming closely-packed networks from which residual melt was extracted by filter pressing, and preserved in leucocratic pods and dykes. Interleaved, non-layered granite may be interpreted to have formed from the magma with initially low crystal fractions.%It is suggested that the intrusion was formed from numerous magma injections representing different stages in the mixing and mingling of felsic and mafic sources. It solidified by gravitation-driven crystal accumulation and flow sorting on the magma chamber floor and on the surfaces of large numbers of xenoliths. Shear stress acting during intrusion might have influenced the formation of magmatic structures.

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In the Variscan Western Tatra granites hybridization phenomena such as mixing and mingling can be observed at the contact of mafic precursors of dioritic composition and more felsic granitic host rocks. The textural evidence of hybridization include: plagioclase–K-feldspar–sphene ocelli, hornblende- and biotite-rimmed quartz ocelli, plagioclase with Ca-rich spike zonation, inversely zoned K-feldspar crystals, mafic clots, poikilitic plagioclase and quartz crystals, mixed apatite morphologies, zoned K-feldspar phenocrysts. The apparent pressure range of the magma hybridization event was calculated at 6.1 kbar to 4.6 kbar, while the temperature, calculated by independent methods, is in the range of 810°C−770°C. U-Pb age data of the hybrid rocks were obtained by in-situ LA-MC-ICP-MS analysis of zircon. The oscillatory zoned zircon crystals yield a concordia age of 368 ± 8 Ma (MSWD = 1.1), interpreted as the age of magma hybridization and timing of formation of the magmatic precursors. It is the oldest Variscan magmatic event in that part of the Tatra Mountains.

crust of Avalonian affinity (462, 426 Ma) and melted metasedimentary rocks of volcanic arc provenance.

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