Identification of discrete low-temperature thermal events in polymetamorphic basement rocks using high spatial resolution FE-SEM-EDX U-Th-Pb dating of uraninite microcrystals

Low-temperature thermal events of Permian (ca. 265 Ma) and Triassic (ca. 215 Ma) age that predate medium-grade regional metamorphism were identified using high spatial resolution field emission-scanning electron microscopy-energy dispersive X-ray (FE-SEM-EDX) U-Th-Pb dating of uraninite microcrystal...

Full description

Saved in:
Bibliographic Details
Published in:Geology (Boulder) 2017-11, Vol.45 (11), p.991-994
Main Authors: Finger, F, Waitzinger, M, Förster, H. J, Kozlik, M, Raith, J. G
Format: Article
Language:English
Subjects:
absolute age
basement
Basement rock
Cenozoic
Crystals
Dating
Dating techniques
EDS spectra
Electron microscopy
electron microscopy data
Europe
Field emission microscopy
Geochronology
igneous and metamorphic rocks
Iron
Lead
Low temperature
Mesozoic
metagranite
metaigneous rocks
metamorphic rocks
Metamorphism
Metamorphism (geology)
Microcrystals
Oligocene
oxides
Paleogene
Paleozoic
Permian
Petrology
polymetamorphism
Radiometric dating
Resolution
Rock
Rocks
Scanning electron microscopy
SEM data
Spatial discrimination
Spatial resolution
spectra
Tauern Window
Temperature
Temperature effects
Tertiary
Triassic
U/Th/Pb
uraninite
Uranium
X-ray spectra
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Low-temperature thermal events of Permian (ca. 265 Ma) and Triassic (ca. 215 Ma) age that predate medium-grade regional metamorphism were identified using high spatial resolution field emission-scanning electron microscopy-energy dispersive X-ray (FE-SEM-EDX) U-Th-Pb dating of uraninite microcrystals in basement rocks of the Tauern Window, Eastern Alps. Three novel points of generic geochronological importance are raised in this study. First, uraninite can be meaningfully dated with FE-SEM-EDX methods, with moderate precision. Second, uraninite is geochronologically robust, even at microcrystal scale, and can survive at least medium-grade metamorphic overprint without being reset. Third, uraninite microcrystals are powerful tools for identifying and dating discrete low-temperature thermal events in orogenic belts. Dating of uraninite microcrystals should be considered an important complementary geochronological method in the study of polymetamorphic rocks.
ISSN:0091-7613
1943-2682
DOI:10.1130/G39370.1