Petrology of weakly differentiated alkaline, high-level intrusive rocks in the Zahořany–Chotiněves belt near Litoměřice (Czech Republic)

Result code in IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F00025798%3A_____%2F18%3A00000179" target="_blank" >RIV/00025798:_____/18:00000179 - isvavai.cz</a>

Alternative codes found

RIV/00216208:11310/18:10392660

Result on the web

<a href="http://www.jgeosci.org/detail/jgeosci.278" target="_blank" >http://www.jgeosci.org/detail/jgeosci.278</a>

DOI - Digital Object Identifier

<a href="http://dx.doi.org/10.3190/jgeosci.278" target="_blank" >10.3190/jgeosci.278</a>

Result language

angličtina

Original language name

Petrology of weakly differentiated alkaline, high-level intrusive rocks in the Zahořany–Chotiněves belt near Litoměřice (Czech Republic)

Original language description

Weakly differentiated rocks such as basaltic trachyandesites occur rather rarely in the České Středohoří Volcanic Complex. We present mineralogical, petrological and geochemical data for a basaltic trachyandesite sill located at the southern edge of the České středohoří Volcanic Complex where several smaller hills form a quasi-continuous belt between Zahořany and Chotiněves. Uniform petrography and chemical composition provide compelling evidence that all individual outcrops form a single large sill, probably with the only exception of the westernmost occurrence at the Křemín hill. The sill is almost 5 km long (SW–NE) and probably up to 3 km wide (NW–SE). The elongated shape of the sill as well as its position suggest that the basaltic trachyandesite magma ascended here along the Litoměřice Fault forming the south-eastern edge of the NE–SW trending Eger Rift. The intermediate composition (49.5–50.3 wt. percent SiO2, 7.8–8.1 wt. percent K2O + Na2O) correlates with decreased concentrations of compatible trace elements such as Cr (15–23 ppm) relative to chemically less evolved basaltic lithologies in the Eger Rift. The low extent of differentiation is also reflected by smooth chondrite-normalized REE patterns (LaN/YbN = 18.2–19.3) with the absence of pronounced Eu- or MREE negative anomaly. The incompatible trace element contents (Sr = 920–1080 ppm; Ba = 840–950 ppm; ƩREE = 280–330 ppm) typify weakly differentiated alkaline volcanic rocks within the Eger Rift. Based on the chemical composition we suggest that these basaltic trachyandesites belong to the České Středohoří Volcanic Complex rather than to MgO-poor foidites of the Central Bohemia Volcanic Field. The age of the emplacement of the sill has been determined by whole rock sample using conventional K–Ar method at 29.12  0.63 Ma. The initial Sr–Nd isotope compositions (87Sr/86Sri = 0.704753; 143Nd/144Ndi = 0.512700), compare well with existing data from the České Středohoří trachybasalts and attest to their common origin. The single large Zahořany–Chotiněves sill partly fills the apparent gap in the differentiation trend between basanites to trachybasalts and trachyandesites to phonolites reported for the alkaline volcanism of the České Středohoří Mts. This intermediate position in the differentiation trend is also supported by numerical modelling of fractional crystallization.

Czech name

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Czech description

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Type

J_imp - 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

Project

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Continuities

I - Institucionalni podpora na dlouhodoby koncepcni rozvoj vyzkumne organizace

Publication year

2018

Confidentiality

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Name of the periodical

Journal of Geosciences

ISSN

1802-6222

e-ISSN

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Volume of the periodical

63

Issue of the periodical within the volume

4

Country of publishing house

CZ - CZECH REPUBLIC

Number of pages

15

Pages from-to

317-331

UT code for WoS article

000454518300004

EID of the result in the Scopus database

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