DOI: 10.1007/s00531-015-1238-3
Scopus记录号: 2-s2.0-84939635318
论文题名: Variscan potassic dyke magmatism of durbachitic affinity at the southern end of the Bohemian Massif (Lower Austria)
作者: Zeitlhofer H. ; Grasemann B. ; Petrakakis K.
刊名: International Journal of Earth Sciences
ISSN: 14373254
出版年: 2016
卷: 105, 期: 4 起始页码: 1175
结束页码: 1197
语种: 英语
英文关键词: Bohemian Massif
; Durbachites
; Late-Variscan extension
; Moldanubian dykes
; Orogenic collapse
; Variscan plutonism
Scopus关键词: dike
; fractional crystallization
; Hercynian orogeny
; lamprophyre
; magma
; magmatism
; mantle source
; mixing
; plutonism
; Austria
; Bohemian Massif
; Lower Austria
英文摘要: Dykes in the Strudengau area (SW Moldanubian Zone, Austria) can be mineralogically divided into lamprophyres (spessartites and kersantites) and felsic dykes (granite porphyries, granitic dykes and pegmatoid dykes). Geochemical analyses of 11 lamprophyres and 7 felsic dykes show evidence of fractional crystallization. The lamprophyres are characterized by metaluminous compositions, intermediate SiO2 contents and high amounts of MgO and K2O; these rocks have high Ba (800–3000 ppm) and Sr (250–1000 ppm) contents as well as an enrichment of large-ion lithophile elements over high field strength elements, typical for enriched mantle sources with variable modifications due to fractionation and crustal contamination. This geochemical signature has been reported from durbachites (biotite- and K feldspar-rich mela-syenites particularly characteristic of the Variscan orogen in Central Europe). For most major elements, calculated fractionation trends from crystallization experiments of durbachites give an excellent match with the data from the Strudengau dykes. This suggests that the lamprophyres and felsic dykes were both products of fractional crystallization and subsequent magma mixing of durbachitic and leucogranitic melts. Rb–Sr geochronological data on biotite from five undeformed kersantites and a locally deformed granite porphyry gave cooling ages of c. 334–318 Ma, indicating synchronous intrusion of the dykes with the nearby outcropping Weinsberger granite (part of the South Bohemian Batholith, c. 330–310 Ma). Oriented matrix biotite separated from the locally deformed granite porphyry gave an Rb–Sr age of c. 318 Ma, interpreted as a deformation age during extensional tectonics. We propose a large-scale extensional regime at c. 320 Ma in the Strudengau area, accompanied by plutonism of fractionated magmas of syncollisional mantle-derived sources, mixed with crustal components. This geodynamic setting is comparable to other areas in the Variscan belt documenting an orogenic wide extension by the end of the Carboniferous. © 2015, Springer-Verlag Berlin Heidelberg. URL: https://www.scopus.com/inward/record.uri?eid=2-s2.0-84939635318&doi=10.1007%2fs00531-015-1238-3&partnerID=40&md5=01f2669178141deb2ed6b069a1621afc
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资源类型: 期刊论文
标识符: http://119.78.100.158/handle/2HF3EXSE/70165
Appears in Collections: 影响、适应和脆弱性 气候减缓与适应
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作者单位: Department of Geodynamics and Sedimentology, University of Vienna, Althanstrasse 14, Vienna, Austria
Recommended Citation:
Zeitlhofer H.,Grasemann B.,Petrakakis K.. Variscan potassic dyke magmatism of durbachitic affinity at the southern end of the Bohemian Massif (Lower Austria)[J]. International Journal of Earth Sciences,2016-01-01,105(4)