Results 31 to 40 of about 29,661 (201)

Timing, sequence, duration and rate of deformation in fold-and-thrust belts: a review of traditional approaches and recent advances from absolute dating (K–Ar illite/U–Pb calcite) of brittle structures

open access: yesComptes Rendus. Géoscience, 2023
Based on a review of literature and a few case studies, this paper summarizes the state of the art on the dating of folds and thrusts, then presents and discusses how recent advances in K–Ar illite and U–Pb calcite geochronology applied to brittle ...
Lacombe, Olivier   +1 more
doaj   +1 more source

SHRIMP Zircon U-Pb Dating of Mid-Pleistocene Dacite and Discussion of Relative Problems

open access: yesYankuang ceshi, 2015
K-Ar and U series disequilibria methods have been applied to geochronology research of young volcanic rocks in Tengchong, China. Previous K-Ar dating methods yielded ages of 0.013 to 17.84 Ma and isochron ages of 0.13 to 2.9 Ma in this area. The U series
LI Lin-lin, WANG Shu-bing, SHI Yu-ruo
doaj   +1 more source

Rutile Ages and Thermometry Along a Grenville Anorthosite Pathway

open access: yesGeochemistry, Geophysics, Geosystems, 2023
The Grenville Orogen, in North America, contains a belt of Proterozoic anorthosite massifs with an episodic emplacement history. These distinctive magmas reflect extensive fractional crystallization of plagioclase from a mafic magma and contain layers ...
Janne Liebmann   +2 more
doaj   +1 more source

U–Pb Geochronology and Stable Isotope Geochemistry of Terrestrial Carbonates, Lower Cretaceous Cedar Mountain Formation, Utah: Implications for Synchronicity of Terrestrial and Marine Carbon Isotope Excursions

open access: yesGeosciences, 2022
The terrestrial Lower Cretaceous Cedar Mountain Formation, Utah, is a critical archive of paleoclimate, tectonics, and vertebrate ecology and evolution.
Erik L. Gulbranson   +10 more
doaj   +1 more source

An algorithm for U–Pb geochronology by secondary ion mass spectrometry [PDF]

open access: yesGeochronology, 2022
Secondary ion mass spectrometry (SIMS) is a widely used technique for in situ U–Pb geochronology of accessory minerals. Existing algorithms for SIMS data reduction and error propagation make a number of simplifying assumptions that degrade the precision
P. Vermeesch
doaj   +1 more source

Zircon U-Pb dating of Mesozoic volcanic and tectonic events in northwest Palmer Land and southwest Graham Land, Antarctica [PDF]

open access: yes, 2009
New whole rock Rb-Sr and zircon U-Pb geochronological data and Sm-Nd isotopic data are presented from the central magmatic arc domain of the Antarctic Peninsula in the area of northwest Palmer Land and southwest Graham Land, Rb-Sr isochrons indicate an ...
Flowerdew, Michael   +5 more
core   +1 more source

Metamorphic and metasomatic evolution of the Western Domain of the Karagwe-Ankole Belt (Central Africa) [PDF]

open access: yes, 2020
The tectonometamorphic evolution of the Western Domain of the Karagwe-Ankole Belt, containing widespread granite-related W-Nb-Ta-Sn mineralization in pegmatites and hydrothermal quartz veins of Early Neoproterozoic age, is largely unknown.
Dewaele, Stijn   +3 more
core   +1 more source

The timing of Barleik Formation and its implication for the Devonian tectonic evolution of Western Junggar, NW China

open access: yesOpen Geosciences, 2021
The timing of Barleik Formation in Xinjiang, NW China, has not been constrained by accurate geochronology yet, while this work is of great significance to help reconstruct the geological tectonic evolution of Western Junggar.
Hui Yuanxiu   +6 more
doaj   +1 more source

Petrographic, chemical and geochronological characteristics of the Onzaga Metarhyolite and its correlation with Ordovician magmatic events in the northern Andes, Colombia

open access: yesBoletín Geológico, 2022
The macroscopic, microscopic, and chemical characteristics as well as crystallization age of the Onzaga Metarhyolite unit are described. The spatiotemporal relationships among the magmatic events that occurred during the Ordovician in the Santander, La ...
Gabriel Rodríguez García
doaj   +1 more source

U-Pn geochronology of deformed metagranites in central Sutherland, Scotland: evidence for widespread late Silurian metamorphism and ductile deformation of the Moine Supergroup during the Caledonian orogeny [PDF]

open access: yes, 2003
Within the Caledonides of central Sutherland, Scotland, the Neoproterozoic metasedimentary rocks of the Moine Supergroup record NW-directed D2 ductile thrusting and nappe assembly, accompanied by widespread tight-to-isoclinal folding and amphibolite ...
Friend, C.R.L.   +5 more
core   +1 more source

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