Petrogenesis of the Cenozoic alkaline volcanic rock series of the České Středohoří Complex (Bohemian Massif), Czech Republic: A case for two lineages
Result description
Cenozoic volcanic rocks of the Ceske Stredohori volcanic complex (CSVC) of the Bohemian Massif form the eastern part of the Central European Volcanic Province. The main pulse of the magmatic activities took place from Late Eocene to Middle Miocene and peaked from ~32 to ~24 Ma. CSVC is composed of lava flows, volcanic clastic deposits and subvolcanic intrusions. The volcanic rocks are sodic (Na2O>K2O) alkaline silica-undersaturated types, which form two main bimodal associations: (1) basanite-phonolite and (2) subordinate trachybasalt-trachyte series, which differ particularly in the alkali-silica space and by the variations particularly of TiO2. The mafic rocks strongly predominate over the felsic types (~6%). The intermediate rocks are rare. Petrological modelling using MELTS software shows that both suites were generated from two distinct parental magmas (basanitic and trachybasaltic) by a fractional crystallization without a noticeable crustal contamination. Some phonolites, particularly their abundances of several incompatible trace elements such as heavy REE and Zr were modified by late- to post-magmatic fluids. The compositional differences among the mafic rocks are, in part, related to variably metasomatically enriched lithospheric mantle. The Nd-Sr isotopic and trace element composition of the mafic magma indicates that the mantle source was slightly heterogeneous amphibole-and/or phlogopite-bearing garnet peridotite. The presence of garnet, amphibole and/or phlogopite indicates lithospheric melting took place close to the asthenosphere-lithosphere boundary. The lithospheric mantle source was probably metasomatically enriched by fluids or melts from an upwelling asthenospheric mantle. The enrichment took place probably during the later stages of the Variscan orogeny. The two mafic parent rock types may be derived from a similar source which showed subtle differences in the source mineralogy mode.
Keywords
Bohemian MassifCentral European volcanic provincecontinental alcaline volcanismfractional crystallizationmagmatic fluids
The result's identifiers
Result code in IS VaVaI
Result on the web
DOI - Digital Object Identifier
Alternative languages
Result language
angličtina
Original language name
Petrogenesis of the Cenozoic alkaline volcanic rock series of the České Středohoří Complex (Bohemian Massif), Czech Republic: A case for two lineages
Original language description
Cenozoic volcanic rocks of the Ceske Stredohori volcanic complex (CSVC) of the Bohemian Massif form the eastern part of the Central European Volcanic Province. The main pulse of the magmatic activities took place from Late Eocene to Middle Miocene and peaked from ~32 to ~24 Ma. CSVC is composed of lava flows, volcanic clastic deposits and subvolcanic intrusions. The volcanic rocks are sodic (Na2O>K2O) alkaline silica-undersaturated types, which form two main bimodal associations: (1) basanite-phonolite and (2) subordinate trachybasalt-trachyte series, which differ particularly in the alkali-silica space and by the variations particularly of TiO2. The mafic rocks strongly predominate over the felsic types (~6%). The intermediate rocks are rare. Petrological modelling using MELTS software shows that both suites were generated from two distinct parental magmas (basanitic and trachybasaltic) by a fractional crystallization without a noticeable crustal contamination. Some phonolites, particularly their abundances of several incompatible trace elements such as heavy REE and Zr were modified by late- to post-magmatic fluids. The compositional differences among the mafic rocks are, in part, related to variably metasomatically enriched lithospheric mantle. The Nd-Sr isotopic and trace element composition of the mafic magma indicates that the mantle source was slightly heterogeneous amphibole-and/or phlogopite-bearing garnet peridotite. The presence of garnet, amphibole and/or phlogopite indicates lithospheric melting took place close to the asthenosphere-lithosphere boundary. The lithospheric mantle source was probably metasomatically enriched by fluids or melts from an upwelling asthenospheric mantle. The enrichment took place probably during the later stages of the Variscan orogeny. The two mafic parent rock types may be derived from a similar source which showed subtle differences in the source mineralogy mode.
Czech name
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Czech description
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Classification
Type
Jimp - Article in a specialist periodical, which is included in the Web of Science database
CEP classification
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OECD FORD branch
10505 - Geology
Result continuities
Project
—
Continuities
I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace
Others
Publication year
2017
Confidentiality
S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů
Data specific for result type
Name of the periodical
American Journal of Science
ISSN
0002-9599
e-ISSN
—
Volume of the periodical
317
Issue of the periodical within the volume
June
Country of publishing house
US - UNITED STATES
Number of pages
30
Pages from-to
677-706
UT code for WoS article
000406011400002
EID of the result in the Scopus database
2-s2.0-85026214666
Basic information
Result type
Jimp - Article in a specialist periodical, which is included in the Web of Science database
OECD FORD
Geology
Year of implementation
2017