Results 21 to 30 of about 19,368 (228)

A comparison between in situ monazite Lu–Hf and U–Pb geochronology [PDF]

open access: yesGeochronology
In complex metamorphic rocks, monazite U–Pb dates can span a wide concordant range, leading to ambiguous geological interpretations (e.g. slow protracted cooling versus multiphase growth).
A. T. De Vries Van Leeuwen   +8 more
doaj   +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

U-Pb Isotopic Dating of Monazite in Granite from the Changjiang Uranium Orefield, Northern Guangdong Province and Its Geological Significance

open access: yesYankuang ceshi, 2022
BACKGROUND The Changjiang uranium ore field in the southern margin of the Zhuguangshan complex pluton is a typical granite-type uranium ore field in China. Zircon U-Pb dating has been used to date ore-bearing granites. However, due to the high content of
CHEN Yan   +6 more
doaj   +1 more source

U–Pb dating and Sm–Nd isotopic analysis of granitic rocks from the Tiris Complex : new constaints on key events in the evolution of the Reguibat Shield, Mauritania [PDF]

open access: yes, 2012
The Reguibat Shield of N Mauritania and W Algeria represents the northern exposure of the West African Craton. As with its counterpart in equatorial West Africa, the Leo Shield, it comprises a western Archaean Domain and an eastern Palaeoproterozoic ...
Abdouloye, T.B.   +6 more
core   +1 more source

Speculations Linking Monazite Compositions to Origin: Llallagua Tin Ore Deposit (Bolivia)

open access: yesResources, 2017
Monazite [(Ce,Th)PO4] from the Llallagua tin ore deposit in Bolivia is characterized by low radiogenic element contents. Previously reported field evidence and mineral associations suggest the mineral formed via direct precipitation from hydrothermal ...
Elizabeth J. Catlos, Nathan R. Miller
doaj   +1 more source

Occurrence of Rare Earth, Iron, Phosphorus and Calcium in High Grade Rare Earth Concentrate

open access: yesKuangchan zonghe liyong, 2022
Rare earth grade of Bayan Obo mixed rare earth concentrate is 65.86%, and the contents of P2O5, CaO and TFe are 11.26%, 3.89% and 1.34%, respectively. Chemical analysis, automatic mineral analysis system, SEM and EDS were used to study the occurrence of ...
Na Li   +3 more
doaj   +1 more source

Separation, reserve estimation and radioactivity responsibility of the economic heavy minerals of East El- Arish black sand, North Sinai, Egypt

open access: yesScientific Reports, 2023
Multi-heavy mineral separation techniques like density, magnetic, and electromagnetic techniques are followed by picking, grain counting, and mineralogical examinations conducted with an environmental scanning electron microscope (ESEM). These techniques
M. Awad   +5 more
doaj   +1 more source

REE-bearing minerals in Drava river sediments, Slovenia, and their potential origin

open access: yesGeologija, 2017
Monazite and xenotime are major ore minerals for rare earth elements (REE), Y, and actinides, a powerful tool for radiometric dating and indicators of the geological genesis of the parent rock.
Aleš Šoster   +3 more
doaj   +1 more source

Plate tectonics: When ancient continents collide [PDF]

open access: yes, 2017
The geological record preserves scant evidence for early plate tectonics. Analysis of eclogites — metamorphic rocks formed in subduction zones — in the Trans-Hudson mountain belt suggests modern-style subduction may have operated 1,800 million years ...
Clare Warren   +4 more
core   +1 more source

Phase Decomposition upon Alteration of Radiation-Damaged Monazite–(Ce) from Moss, Østfold, Norway

open access: yesCHIMIA, 2010
The internal textures of crystals of moderately radiation-damaged monazite–(Ce) from Moss, Norway, indicate heavy, secondary chemical alteration.
Lutz Nasdala   +8 more
doaj   +1 more source

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