Results 51 to 60 of about 19,529 (228)

Direct dating of mid-crustal shear zones with synkinematic allanite:new in situ U-Th-Pb geochronological approaches applied to the Mont Blanc massif [PDF]

open access: yes, 2013
International audienceDating the timing of motion on crustal shear zones is of tremendous importance for understanding the assembly of orogenic terranes.
Cenki-tok, Benedicte   +4 more
core   +3 more sources

Confirmation of the impact origin of the Late Ordovician Tvären impact structure (southeast Sweden) and emplacement of impactites in a marine setting

open access: yesMeteoritics &Planetary Science, EarlyView.
Abstract The Tvären structure in southeastern Sweden has been listed as a confirmed marine‐target impact structure for decades. However, to date, no measurements and/or indexed data of planar deformation features in quartz grains from the structure have been published or any other unequivocal evidence of impact.
Katarzyna J. Gajewska   +6 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

Ductile Extrusion Triggered by Continental Collision in NE Brazil

open access: yesTerra Nova, EarlyView.
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

Zircon ages in granulite facies rocks: decoupling from geochemistry above 850 °C? [PDF]

open access: yes, 2018
Granulite facies rocks frequently show a large spread in their zircon ages, the interpretation of which raises questions: Has the isotopic system been disturbed? By what process(es) and conditions did the alteration occur?
A Boriani   +120 more
core   +1 more source

Progressively Fenitised Schist and Carbonatitic Clasts From a Metasomatic Aureole Beneath the Alkalic Dunedin Volcano, Otago, New Zealand

open access: yesNew Zealand Journal of Geology and Geophysics, Volume 69, Issue 2, June 2026.
Clasts of albite‐porphyroblastic quartzofeldspathic schist, derived from the Otago Schist basement, occur within the Port Chalmers Breccia, a diatreme at the centre of the Dunedin stratovolcano, New Zealand. Schists have undergone varying degrees of replacement reactions (at temperatures of 300° to >500°C) producing hornfelses, with Ca‐ and K‐enriched ...
Alan F. Cooper
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

Peixe Zircon as a Quality Control Reference Material in U‐Pb Geochronology by LA‐ICP‐MS

open access: yesGeostandards and Geoanalytical Research, Volume 50, Issue 2, Page 369-389, June 2026.
Key Points Peixe#0 zircon was characterised for U‐Pb geochronology using CA‐ID‐TIMS, SIMS and a long‐term LA‐ICP‐MS data set. The consistent results establish Peixe#0 as a reference material for U‐Pb quality control. Trace element heterogeneity requires careful, CL‐guided spot selection.
Margareth Sugano Navarro   +7 more
wiley   +1 more source

Processing of Monazite Sands

open access: yesIndustrial & Engineering Chemistry, 1958
For the past ten years, much effort has been expended by several research teams to develop an economic process for recovering thorium, rare earths and uranium from monazite sands. Recently, a process was developed at the Ames Laboratory which possessed many attractive features.
Barghusen, John, Smutz, M.
openaire   +5 more sources

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