Results 31 to 40 of about 29,350 (195)

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

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

U-Pb SHRIMP zircon dating of Grenvillian metamorphism in Western Sierras Pampeanas (Argentina) : correlation with the Arequipa-Antofalla craton and constraints on the extent of the Precordillera Terrane [PDF]

open access: yes, 2006
The Sierras Pampeanas of Argentina, the largest outcrop of pre-Andean crystalline basement in southern South America, resulted from plate interactions along the proto-Andean margin of Gondwana, from as early as Mesoproterozoic to Late Paleozoic times (e ...
C. Mark Fanning   +31 more
core   +4 more sources

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

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

Evaluating the construction and evolution of upper crustal magma reservoirs with coupled U/Pb zircon geochronology and thermal modeling:A case study from the Mt. Capanne pluton (Elba, Italy) [PDF]

open access: yes, 2015
Evaluating mechanisms and rates for magma transport and emplacement in the upper crust is important in order to predict the thermal and rheological state of the crust, and understand the relationship between plutonism and volcanism. U–Pb geochronology on
Annen, Catherine   +2 more
core   +2 more sources

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

Multianalytical provenance analysis of Eastern Ross Sea LGM till sediments (Antarctica): Petrography, geochronology, and thermochronology detrital data [PDF]

open access: yes, 2017
In order to reveal provenance of detrital sediments supplied by West Antarctic Ice Sheet (WAIS), 19 glaciomarine cores of Last Glacial Maximum age were analyzed from Eastern Ross Sea and Sulzberger Bay.
Andreucci, Benedetta   +4 more
core   +2 more sources

µID-TIMS: spatially resolved high-precision U–Pb zircon geochronology [PDF]

open access: yesGeochronology
We present a novel methodology for spatially resolved high-precision U–Pb geochronology of individual growth domains in complex zircon. Our approach utilizes a multi-ion-species (Xe+/Ar+) plasma focused ion beam (PFIB)–femtosecond (fs) laser system ...
S. Markovic   +5 more
doaj   +1 more source

Detrital zircon SHRIMP U-Pb age study of the Cordillera Darwin Metamorphic Complex of Tierra del Fuego : sedimentary sources and implications for the evolution of the Pacific margin of Gondwana [PDF]

open access: yes, 2010
The Cordillera Darwin Metamorphic Complex in the southernmost Andes includes a basement of probable Palaeozoic age, a mid-Jurassic and younger volcano-sedimentary cover, and a suite of Jurassic granites, all of which were jointly metamorphosed during the
Calderon, M.   +6 more
core   +1 more source

Home - About - Disclaimer - Privacy