Results 131 to 140 of about 823 (158)
Some of the next articles are maybe not open access.
Magnetic fabric transposition in folded granite sills in Variscan orogenic wedge
Journal of Structural Geology, 2017Abstract New approach involving evaluation of anisotropy of magnetic susceptibility (AMS) data in stereoplots and Jelinek's P j –T space, Vollmer's eigenvalue and microstructural analyses is proposed to discriminate between homogeneous and superposed deformation in granites.
Závada, Prokop +8 more
openaire +2 more sources
The chemical composition of uraninite in Variscan granites of the Erzgebirge, Germany
Mineralogical Magazine, 1999AbstractUraninite is widespread as an accessory mineral in the Erzgebirge granites. It occurs throughout the entire comagmatic series of strongly peraluminous S-type Li-mica granites and has been discovered in more evolved transitional I-S type biotite and two-mica granites, but is rare in those of A-type affinity.
openaire +2 more sources
Physics and Chemistry of the Earth, 2003
Abstract Granites usually display a bimodal distribution of their magnetic susceptibility. One mode corresponds to susceptibilities of the order of 10 −5 –10 −4 and the other one to those of the order of 10 −3 –10 −2 [SI]. The former mode, which corresponds to ilmenite-bearing granites, is often equated with the S (sedimental) type, while the ...
František Hrouda, Milan Kohut
exaly +2 more sources
Abstract Granites usually display a bimodal distribution of their magnetic susceptibility. One mode corresponds to susceptibilities of the order of 10 −5 –10 −4 and the other one to those of the order of 10 −3 –10 −2 [SI]. The former mode, which corresponds to ilmenite-bearing granites, is often equated with the S (sedimental) type, while the ...
František Hrouda, Milan Kohut
exaly +2 more sources
Geothermal Control of Granite Compositions in the Variscan Orogenic Belt
Nature Physical Science, 1973I HAVE shown that the average compositions of granites in the Variscan, Caledonian and Alpine orogenic belts differ, and have attributed their differences to formation by partial melting under different geothermal gradients1. A geochemical examination of the granites in the Caledonian orogenic belt suggested that regional variation within the orogenic ...
openaire +1 more source
Zircons in Variscan granites from the Slavonian Mountains, Croatia
2010The Slavonian Mountains in Croatia expose Variscan crystalline basement of the Tisia terrane. Apart from different metamorphic units, this basement comprises large bodies of Variscan granites. In the course of current attempts to constrain the formation ages of these granitic rocks by means of LA-SF-ICP-MS-based U-Pb zircon dating, a detailed study of ...
Tibljaš, Darko, Balen, Dražen
openaire +2 more sources
Structure of the Castillo granite, Southwest Spain: Variscan deformation of a late Cadomian pluton
Tectonics, 1999A geometrical reconstruction of the 500 Ma old Castillo granite pluton (SW Iberia) is completed on the basis of structural and geophysical (rock magnetism) techniques. The pluton is intrusive into latest Proterozoic‐earliest Cambrian metasediments and conforms a tabular intrusion 6 km in diameter and 1.7 km thick that was emplaced at a depth of 10 km ...
L. Eguíluz, A. Apraiz, B. Ábalos
openaire +1 more source
Variscan subduction of an Ordovician granite : the Lévézou massif, French Massif Central
2015The Variscan Belt is usually interpreted as the result of an oceanic subduction followed by continental collision. The subducted ocean is represented by eclogitic lenses enclosed in amphibolite-facies rocks. This rock assemblage, called the Leptyno-Amphibolic Group (LAG), is considered as a suture unit that separates two different continental fragments
Lotout, Caroline +5 more
openaire +2 more sources
Journal of the Geological Society, 1996
Apatite fission-track (AFT) dates for granitic samples from surface exposures and deep boreholes in the 293.3 ± 1.2 Ma Carnmenellis granite, west Cornwall, decrease radically from 130 ± 28 (2 σ ) Ma at surface to 26 ± 6 Ma at c.
Y. CHEN +5 more
openaire +1 more source
Apatite fission-track (AFT) dates for granitic samples from surface exposures and deep boreholes in the 293.3 ± 1.2 Ma Carnmenellis granite, west Cornwall, decrease radically from 130 ± 28 (2 σ ) Ma at surface to 26 ± 6 Ma at c.
Y. CHEN +5 more
openaire +1 more source
Journal of Structural Geology, 2017
Abstract A major event of plutonic activity occurred all across the Central Iberian Zone of the Iberian Variscan Belt at the end of Late Paleozoic Variscan collisional tectonism. The present study focuses on the western sector of the Viseu late-post-tectonic batholith (central Portugal), a large composite intrusion comprising three main plutonic ...
B. Valle Aguado +6 more
openaire +3 more sources
Abstract A major event of plutonic activity occurred all across the Central Iberian Zone of the Iberian Variscan Belt at the end of Late Paleozoic Variscan collisional tectonism. The present study focuses on the western sector of the Viseu late-post-tectonic batholith (central Portugal), a large composite intrusion comprising three main plutonic ...
B. Valle Aguado +6 more
openaire +3 more sources
Hydrothermal alteration of Variscan granites, southern Schwarzwald, Federal Republic of Germany
Contributions to Mineralogy and Petrology, 1990Hercynian S-type granites from the southeastern Schwarzwald granite series represent cogenetic biotite-and two-mica granites. Oxygen- and hydrogen-isotope data show that hydrothermal alteration invoking isotopically light surface waters resulted in a drastic reduction in δ18O and δD and pronounced disequilibrium between the minerals.
openaire +1 more source