Results 31 to 40 of about 1,390 (185)

Apatite in Carbonatite Preserving Primary Magmatic, Post‐Magmatic Overgrowth, and Post India‐Asia Collision‐Related Hydrothermal Alteration: Evidenced From U–Pb Isotope and Trace Element Geochemistry

open access: yesGeological Journal, EarlyView.
U–Pb isotope and trace element geochemistry of apatite from carbonatites of Peshawar Plain Alkaline Igneous Province, western Himalaya shows Permo‐Carboniferous magmatism, an additional magmatic pulse during Cretaceous, and post‐magmatic hydrothermal/metasomatism during Oligocene. ABSTRACT U–Pb isotope and trace element geochemistry of apatite combined
Mehboob ur Rashid   +9 more
wiley   +1 more source

From ID-TIMS U-Pb dating of single monazite grain to APT-nanogeochronology: application to the UHT granulites of Andriamena (North-Central Madagascar)

open access: yesBSGF - Earth Sciences Bulletin
The causes of U-Pb isotopic discordance documented by Paquette et al. (2004) in monazite grains from the ultra-high temperature (UHT) granulite of the Andriamena unit of Madagascar are re-evaluated in the light of nanoscale crystal-chemical ...
Turuani M.J.   +11 more
doaj   +1 more source

Assessment and Correction of Non‐Linearity Effects for In Situ Rb‐Sr Geochronology Applied to High 87Rb/86Sr Mica

open access: yesGeostandards and Geoanalytical Research, EarlyView.
Key Points Measurement of 86Sr at count rates < 1500 cps can result in statistical bias. Non‐linear signals in analogue detection mode (e.g., Rb) present a challenge for accurately dating high 87Rb/86Sr mica (> 1000). Accounting for these considerations, high 87Rb/86Sr mica are dated here with accuracies of ∼ 1%.
Duane C. Petts   +5 more
wiley   +1 more source

Timing of Palaeoproterozoic crustal shearing in the central Fennoscandian Shield according to U-Pb data from associated granitoids, Finland [PDF]

open access: yesBulletin of the Geological Society of Finland, 2001
Granitoids in the Finnish part of the Fennoscandian Shield were created by numerous Archaean and Palaeoproterozoic tectonic events. Late phases of Palaeoproterozoic, Svecokarelian deformation created ductile, crustal-scale shear zones, of which the N-S ...
M. Vaasjoki, A. Kärki, K. Laajoki
doaj   +1 more source

Application of Automated Mineral Identification and Characterization System to Identify Minerals and Occurrences of Elements in Jixiangyu Rare Earth Deposit of Eastern Liaoning

open access: yesYankuang ceshi, 2023
BACKGROUNDIn Liaoning Province, there are limited known types of rare earth deposits, and historically, exploration and evaluation efforts have mainly focused on monazite placer and alkaline rock type rare earth deposits. Less attention has been given to
Xiaoxu SUN   +7 more
doaj   +1 more source

Resolving Micrometre‐Scale Zircon Growth in Silicic Systems by 7 μm LA‐MC‐ICP‐MS U‐Pb Dating: Linking Petrology and Geochronology in Silicic Volcanic and Granitic Rocks from Victoria, Australia

open access: yesGeostandards and Geoanalytical Research, EarlyView.
Key Points 7 μm spot‐diameter LA‐MC‐ICP‐MS analyses yield accurate zircon U‐Pb ages. 1013 Ω amplifier resistors improve low‐signal Pb measurements. Saturn correction protocols minimise down‐hole fractionation effects. We present a systematic evaluation of high spatial‐resolution zircon U‐Pb dating using a Thermo Scientific Neoma multi‐collector ICP‐MS ...
Cristiano Lana, John D. Clemens
wiley   +1 more source

Notes on monazite [PDF]

open access: yesAmerican Journal of Science, 1900
n ...
openaire   +2 more sources

The Ames impact structure, Oklahoma: New radioisotopic constraints and implications for North American impact chronology

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract The Ames impact structure (Oklahoma) is thought to have formed during the Ordovician Meteor Event, based on conodont biostratigraphy of its crater fill. Here, U–Pb zircon dates from its impact‐melt portion, conducted using secondary ion mass spectrometry and laser ablation–inductively coupled plasma–mass spectrometry (n = 37 spots), yield a ...
Elizabeth J. Catlos   +9 more
wiley   +1 more source

A Survey on Various Methods of Extraction and Recovery of Thorium

open access: yesJournal of the Turkish Chemical Society, Section A: Chemistry, 2021
In this survey, some methods of extraction of thorium such as selective extraction of thorium using phosphorodiamidate, selective cloud point extraction of thorium, extraction of thorium from sulfuric acid baking and leaching of monazite, extraction of ...
Sugyani DASH   +3 more
doaj   +1 more source

Ductile Extrusion Triggered by Continental Collision in NE Brazil

open access: yesTerra Nova, Volume 38, Issue 4, Page 266-277, August 2026.
ABSTRACT The Borborema Province in northeastern Brazil hosts one of the world's largest strike‐slip shear zone networks, active during the late Neoproterozoic assembly of West Gondwana. Whether these shear zones initiated during active continental collision or as a post‐orogenic response to far‐field stresses remains debated.
L. R. Tesser   +6 more
wiley   +1 more source

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