Accessory Minerals in Felsic Igneous Rocks - Part 6: Composition of monazite-(Ce), xenotime-(Y) and zircon from the late-Variscan Fichtelgebirge/Smrčiny granites (Germany, Czech Republic)
Cite as:
Förster, Hans-Jürgen (2020): Accessory Minerals in Felsic Igneous Rocks - Part 6: Composition of monazite-(Ce), xenotime-(Y) and zircon from the late-Variscan Fichtelgebirge/Smrčiny granites (Germany, Czech Republic). GFZ Data Services. https://doi.org/10.5880/GFZ.4.8.2020.002
Status
I N R E V I E W : Förster, Hans-Jürgen (2020): Accessory Minerals in Felsic Igneous Rocks - Part 6: Composition of monazite-(Ce), xenotime-(Y) and zircon from the late-Variscan Fichtelgebirge/Smrčiny granites (Germany, Czech Republic). GFZ Data Services. https://doi.org/10.5880/GFZ.4.8.2020.002
Abstract
This data set is the sixth part of a series reporting chemical data for accessory minerals from felsic igneous rocks. It assembles the results of electron-microprobe spot analyses of monazite-(Ce), xenotime-(Y) and zircon from the late-Variscan granites of the Fichtelgebirge/Smrčiny in the Saxothuringian Zone of the Variscan Orogen in Germany/ Czech Republic.
The granites form an older, Namurian intrusive complex (OIC-p and OIC-e) and a younger, post-Westphalian intrusive complex (YIC-1 and YIC-2). Both complexes have distinct radioactive accessory-mineral assemblages and compositions. The OIC-p biotite monzogranites contain monazite-(Ce) and minor thorite, but apparently lack magmatic xenotime-(Y) and uraninite. The more evolved OIC-e two-mica granites bear monazite-(Ce) occasionally rich in Th (up to 21 wt% ThO2) and U (8 wt% UO2), xenotime-(Y) of moderate U content (< 3.3 wt% UO2), and uraninite poor in Th and the REE. The most fractionated YIC Li-mica granites (YIC-2) may contain monazite extremely high in Th (40.5 wt% ThO2) and U (8.6 wt% UO2), which classify as cheralite-(Ce), xenotime-(Y) rich in U (6.3 wt% UO2) and such with elevated Y/Ho ratios (up to 48), and also a Th–REE-poor uraninite. In these granites, zircon may contain up to 5 wt% HfO2 and display low, fractionated Zr/Hf ratios (down to 10).
The data set contains the complete pile of electron-microprobe analyses for monazite-(Ce) (MONA-FICH-2020), xenotime-(Y) (XENO-FICH-2020), and zircon (ZIRC-FICH-2020). All tables are presented as Excel (xlsx) and machine-readable txt formats. The content of the tables and further information on the granites and regional geology are provided in the data description file.
Authors
Förster, Hans-Jürgen;GFZ German Research Centre for Geosciences, Potsdam, Germany
Contact
Förster, Hans-Jürgen
(Senior Scientist); GFZ German Research Centre for Geosciences, Potsdam, Germany;
affiliation (affiliationIdentifier=0000-0002-4654-0382 affiliationIdentifierScheme=ORCID): GFZ German Research Centre for Geosciences, Potsdam, Germany
titles
title: Accessory Minerals in Felsic Igneous Rocks - Part 6: Composition of monazite-(Ce), xenotime-(Y) and zircon from the late-Variscan Fichtelgebirge/Smrčiny granites (Germany, Czech Republic)
CharacterString: Accessory Minerals in Felsic Igneous Rocks - Part 6: Composition of monazite-(Ce), xenotime-(Y) and zircon from the late-Variscan Fichtelgebirge/Smrčiny granites (Germany, Czech Republic)
CharacterString: This data set is the sixth part of a series reporting chemical data for accessory minerals from felsic igneous rocks. It assembles the results of electron-microprobe spot analyses of monazite-(Ce), xenotime-(Y) and zircon from the late-Variscan granites of the Fichtelgebirge/Smrčiny in the Saxothuringian Zone of the Variscan Orogen in Germany/ Czech Republic.
The granites form an older, Namurian intrusive complex (OIC-p and OIC-e) and a younger, post-Westphalian intrusive complex (YIC-1 and YIC-2). Both complexes have distinct radioactive accessory-mineral assemblages and compositions. The OIC-p biotite monzogranites contain monazite-(Ce) and minor thorite, but apparently lack magmatic xenotime-(Y) and uraninite. The more evolved OIC-e two-mica granites bear monazite-(Ce) occasionally rich in Th (up to 21 wt% ThO2) and U (8 wt% UO2), xenotime-(Y) of moderate U content (< 3.3 wt% UO2), and uraninite poor in Th and the REE. The most fractionated YIC Li-mica granites (YIC-2) may contain monazite extremely high in Th (40.5 wt% ThO2) and U (8.6 wt% UO2), which classify as cheralite-(Ce), xenotime-(Y) rich in U (6.3 wt% UO2) and such with elevated Y/Ho ratios (up to 48), and also a Th–REE-poor uraninite. In these granites, zircon may contain up to 5 wt% HfO2 and display low, fractionated Zr/Hf ratios (down to 10).
The data set contains the complete pile of electron-microprobe analyses for monazite-(Ce) (MONA-FICH-2020), xenotime-(Y) (XENO-FICH-2020), and zircon (ZIRC-FICH-2020). All tables are presented as Excel (xlsx) and machine-readable txt formats. The content of the tables and further information on the granites and regional geology are provided in the data description file.
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;GFZ German Research Centre for Geosciences, Potsdam, Germany
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