National Repository of Grey Literature 2 records found  Search took 0.02 seconds. 
Contribution to geodynamic evolution and post-collisional magmatic activity in the Arabian-Nubian Shield (East African Orogeny) and southwestern Moldanubian Zone (Central European Variscides)
Megerssa, Leta Alemayehu ; Verner, Kryštof (advisor) ; Závada, Prokop (referee) ; Johnson, Kenneth (referee)
The Variscan orogenic belt along the exhumed root domain, known as the Moldanubian Zone as well as the Arabian-Nubian Shield (ANS) in the East African Orogeny (EAO) of Ethiopia, are considered as typical areas for studying late-orogenic (post-collisional) processes and magmatism. Based on a wider range of field and analytical methods: field structural mapping, anisotropy of magnetic susceptibility (AMS) analysis, thermobarometric calculation and P-T evolution, conventional U/Pb dating, a reconstruction of geodynamic evolution and magmatism in the southwestern part of Moldanubian Zone (Bohemian Massif) and Tokar-Barka Terrain (southern part of Arabian-Nubian Shield is undertaken. The Variscan case portrays the peculiar overprint by the Late Orogenic tectonothermal event which is absent in the case of the Arabian-Nubian Shield (ANS) hence offering a compelling contrast to investigate the possible underlying mechanism involved for the different processes in the post-orogenic phase. In the southern ANS a post-collisional intrusive Chewo pluton composed of monzodiorite and quartz monzonite marks the late tectonic overprint which intruded into a low-grade Neoproterozoic juvenile crustal Tokar-Barka terrane. Thermobarometric estimations indicate its emplacement to be c. 10-13 Km depth, idealized from AMS...
Emplacement and fabric patterns of plutons in the eastern periphery of the Moldanubian Zone; implications for geodynamic evolution of the Bohemian Massif
Vondrovic, Lukáš ; Verner, Kryštof (advisor) ; Melichar, Rostislav (referee) ; Johnson, Kenneth (referee)
The Ph.D. thesis focuses on an analysis of the structural record and geochronology of selected calc-alkaline plutons emplaced in the rocks of the eastern periphery of the Moldanubian Zone (eastern margin of the Bohemian Massif). In addition, it includes an analysis of the tectonic and metamorphic record of the host rocks of the Polička and Zábřeh Units. The results revealed a number of important implications regarding the geodynamic evolution of the north- eastern part of the Bohemian Massif. The rocks of the Zábřeh Unit were metamorphosed under middle temperature and lower pressure conditions (T: 660 C, P: 0.6 Gpa). The structural record is defined by the superposition of regional steep E-W trending metamorphic fabric (S1) which was variably obliterated by means of intensive folding into S2 flat-lying foliation. This unit is in the northern part intruded by calc-alkaline rocks of the Zábřeh Intrusive Complex (354±4Ma, U/Pb on zircons) with calculated P-T crystallisation conditions of 706-795 řC and P: 0.3-0.4 Gpa. A contact metamorphic event took place within the host rocks in the proximity of the intrusion (T: 599-663 C, P: 0.4 Gpa). The internal fabric of the Zábřeh Intrusive Complex exhibits a magmatic to submagmatic gradient and the orientation of the intrusive contacts and magmatic...

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1 Johnson, Kailyn
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