3D density modelling of Gemeric granites of the Western Carpathians

Abstract

Abstract:The position of the Gemeric Superunit within the Western Carpathians is unique due to the occurrence of the Lower Palaeozoic basement rocks together with the autochthonous Upper Palaeozoic cover. The Gemeric granites play one of the most important roles in the framework of the tectonic evolution of this mountain range. They can be observed in several small intrusions outcropping in the western and south-eastern parts of the Gemeric Superunit. Moreover, these granites are particularly interesting in terms of their mineralogy, petrology and ages. The comprehensive geological and geophysical research of the Gemeric granites can help us to better understand structures and tectonic evolution of the Western Carpathians. Therefore, a new and original 3D density model of the Gemeric granites was created by using the interactive geophysical program IGMAS. The results show clearly that the Gemeric granites represent the most significant upper crustal anomalous low-density body in the structure of the Gemeric Superunit. Their average thickness varies in the range of 5-8 km. The upper boundary of the Gemeric granites is much more rugged in comparison with the lower boundary. There are areas, where the granite body outcrops and/or is very close to the surface and places in which its upper boundary is deeper (on average 1 km in the north and 4-5 km in the south). While the depth of the lower boundary varies from 5-7 km in the north to 9-10 km in the south. The northern boundary of the Gemeric granites along the tectonic contact with the Rakovec and Klátov Groups (North Gemeric Units) was interpreted as very steep (almost vertical). The results of the 3D modelling show that the whole structure of the Gemeric Unit, not only the Gemeric granite itself, has an Alpine north-vergent nappe structure. Also, the model suggests that the Silicicum-Turnaicum and Meliaticum nappe units have been overthrusted onto the Golčatov Group.

Primary Minerals and Age of The Hydrothermal Quartz Veins Containing U-Mo-(Pb, Bi, Te) Mineralization in the Majerská Valley near Čučma (Gemeric Unit, Spišsko-Gemerské Rudohorie Mts., Slovak Republic)

“…The Gelnica Group is, from the bottom to top, divided into the Vlachovo, Bystrý Potok and Drnava Formations (sensu [16,21,22]) intruded by the Permian S-type Gemeric granites [23]. According to geophysics data, these are apophyses of a larger granite body underlying metamorphosed volcano-sedimentary sequences of the Gemeric Unit [24].…”

Accessory minerals and evolution of tin-bearing S-type granites in the western segment of the Gemeric Unit (Western Carpathians)

“…Due to high volatile flux, the evolution of the specialized S-type granites is different from other Variscan granites in the Western Carpathians. The preserved granite cupolas of larger hidden granite body (Plančár et al 1977;Šefara et al 2017), intensive in-situ differentiation and percolation of fluids resulted in formation of various accessory phases in cupolas, including those with metallogenic significance. The tin bearing granite was described in detail by Malachovský et al (1992); Dianiška et al (2002); Kubiš & Broska (2010);Breiter et al (2015) on results from a drilling programme in the Dlhá dolina or Podsúľová area in the Gemeric Unit.…”

Geodynamics

“…Розвиток інтерпретаційних можливостей гравірозвідки в цьому напрямку ґрунтується на роботах В. М. Страхова, Є. Г. Булаха, С. С. Красовського, О. І. Кобрунова, С. Г. Анікеєва. У сучасних дослідженнях глибинної густинної будови земної кори важливу роль відіграють методи 3D-моделювання за комплексом геофізичних даних , Šefara, 2017, Stefaniuk, 2009.…”