Active Magmatic Underplating in Western Eger Rift, Central Europe. Issue 12 (6th December 2017)

• Record Type: Journal Article
• Authors: Hrubcová, Pavla; Geissler, Wolfram H.; Bräuer, Karin; Vavryčuk, Václav; Tomek, Čestmír; Kämpf, Horst
• Is Part Of: Tectonics. Volume 36:Issue 12(2017)
• Page Start: 2846
• Page End: 2862
• Publication Date: 2017-12-06
• Subjects: Eger Rift -- active intraplate magmatic underplating -- mantle‐derived fluids -- high‐velocity lower crust -- reflectivity -- reflection‐free magma body; Geology, Structural -- Periodicals; 551.8
• DOI: 10.1002/2017TC004710
• Languages: English
• ISSNs: 0278-7407

Abstract

Plain Language Summary: The Eger Rift, active element of the European Cenozoic Rift System, is associated with intense Cenozoic intraplate alkaline volcanism and system of sedimentary basins. The intracontinental Cheb Basin at its western part displays geodynamic activity with fluid emanations, persistent seismicity, Cenozoic volcanism, and neotectonic crustal movements at the intersections of major intraplate faults. In this paper, we study detailed geometry of the crust/mantle boundary and its possible origins. Based on seismic data from reflection and refraction profiles and from local seismicity, we identify significant lateral variations of the high‐velocity lower crust and relate them to mantle‐derived fluids and petrology. The observations point to a local‐scale magmatic emplacement at the base of the continental crust within a new rift environment. The concept of magmatic underplating is evidenced by detecting two types of lower crust: a high‐velocity lower crust with pronounced reflectivity and a high‐velocity reflection‐free lower crust. The character of the underplated material enables to differentiate timing and tectonic setting of two episodes with different times of origin of underplating events. Spatial and temporal relations to recent geodynamic processes suggest active magmatic underplating in the intracontinental setting.