Felsic diapirism beneath the high-grade terrains in the eastern Bohemian Massif - refraction tomography evidence

0507297 - GFÚ 2020 RIV CZ eng J - Článek v odborném periodiku
Novotný, Miroslav
Felsic diapirism beneath the high-grade terrains in the eastern Bohemian Massif - refraction tomography evidence.
Journal of Geosciences. Roč. 63, č. 3 (2018), s. 227-251. ISSN 1802-6222. E-ISSN 1803-1943
Grant CEP: GA MŽP SB/630/3/02
Institucionální podpora: RVO:67985530
Klíčová slova: high-grade terrains * eastern Bohemian Massif * depth-recursive refraction tomography
Obor OECD: Volcanology
Impakt faktor: 1.275, rok: 2018
Způsob publikování: Open access
http://www.jgeosci.org/detail/jgeosci.270

Unlike standard ray-based tomographies, the Depth-Recursive Tomography on Grid (DREG) method assesses the travel-time fit at each model grid node using a regular network of refraction rays. This concept allows estimating the lateral resolution achieved in the velocity image that regards the chosen confidence levels and the strength of velocity anomalies. Recently, The DRTG has been applied to the S01 and CEL09 refraction profiles imaging major crustal structures of the Bohemian Massif in enhanced resolution. Now, similar enhanced velocity models are derived along the S04, S02 and S03 profiles mapping the Sudetic and Moldanubian regions. The S02 and S03 and the transverse CEL09 and S04 velocity sections particularly imaged the subsurface of the Moldanubian high-grade belts to the 15-20 km depth. Their common interpretation revealed the signatures of exhumation processes from upper-mantle depths assumed in this region. Along the western belt of Moldanubian high-grade rocks, the S02 section revealed an extensive HV body shallowly emplaced beneath the high-grade Gfohl and Ostrong assemblages. Three mid-crustal HV elevations, correlating with local magnetic anomalies, obviously represent the deep sources of this HV mafic body and indicate its autochthonous nature. Finally, the DRTG also detected a shallowly emplaced ITV layer beneath the Saxonian Granulite Massif at the S04 section. The mid-crustal HV-LV-HV diapiric triplets and shallowly emplaced HV bodies are likely typical of the high-grade terrains. The observed patterns resulted from contemporaneous intrusion of mafic and, more viscous, felsic magmas during continental collision. The inferred structural features of subduction-exhumation processes are suggested to further constrain their thermo-mechanic modeling.
Trvalý link: http://hdl.handle.net/11104/0298308