scholarly journals The Geochronology and Geochemistry of Zircon as Evidence for the Reconcentration of REE in the Triassic Period in the Chungju Area, South Korea

Minerals ◽  
2020 ◽  
Vol 10 (1) ◽  
pp. 49
Author(s):  
Sang-Gun No ◽  
Maeng-Eon Park

The Chungju rare-earth element (REE) deposit is located in the central part of the Okcheon Metamorphic Belt (OMB) in the Southern Korean Peninsula and research on REE mineralization in the Gyemyeongsan Formation has been continuous since the first report in 1989. The genesis of the REE mineralization that occurred in the Gyemyeongsan Formation has been reported by previous researchers; theories include the fractional crystallization of alkali magma, magmatic hydrothermal alteration, and recurrent mineralization during metamorphism. In the Gyemyeongsan Formation, we discovered an allanite-rich vein that displays the paragenetic relationship of quartz, allanite, and zircon, and we investigated the chemistry and chronology of zircon obtained from this vein. We analyzed the zircon’s chemistry with an electron probe X-ray micro analyzer (EPMA) and laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS). The grain size of the zircon is as large as 50 µm and has an inherited core (up to 15 µm) and micrometer-sized sector zoning (up to several micrometers in size). In a previous study, the zircon ages were not obtained because the grain size was too small to analyze. In this study, we analyzed the zircon with laser ablation multi-collector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) for dating purposes. The REE patterns and occurrence of zircon in the quartz–allanite vein match well with previous reported recrystallized zircon, while the behavior of the trace elements shows differences with magmatic and hydrothermal zircon. The 206Pb/238U ages obtained from the zircon in the quartz–allanite vein are from 240.1 ± 2.9 to 257.1 ± 3.5 Ma and this age is included in the tectonic evolution period of the study area. Therefore, we suggest that the quartz–allanite veins in the Gyemyeongsan Formation were formed during the late Permian to early Triassic metamorphic period and the zircon was recrystallized at that time. The Triassic age is the first reported age with zircon dating in the Gyemyeongsan Formation and will be an important data-point for the study of the tectonic evolution of the OMB.

2016 ◽  
Vol 31 (4) ◽  
pp. 1030-1033 ◽  
Author(s):  
J. S. Hamilton ◽  
E. L. Gorishek ◽  
P. M. Mach ◽  
D. Sturtevant ◽  
M. L. Ladage ◽  
...  

A new single Peltier element ablation cell is described and its applicability to biological sampling discussed to evaluate its performance.


2017 ◽  
Vol 32 (8) ◽  
pp. 1500-1507 ◽  
Author(s):  
Jorge Moreda-Piñeiro ◽  
Alicia Cantarero-Roldán ◽  
Antonio Moreda-Piñeiro ◽  
José Ángel Cocho ◽  
Pilar Bermejo-Barrera

An approach by laser ablation (LA) coupled with inductively coupled mass spectrometry (ICP-MS) for multi-element determination in whole blood is described.


2004 ◽  
Vol 57 (10) ◽  
pp. 921 ◽  
Author(s):  
Sebastien Rauch ◽  
Gregory M. Morrison

Recent developments in laser microprobes and the coupling of laser ablation (LA) to inductively coupled plasma mass spectrometry (ICP-MS) has opened up the possibility for detailed analysis of individual sediment grains and the elucidation of metal association with bulk elements and phases. Here, LA–ICP-MS is used for the micrometer-resolved, multi-element analysis of Pb and bulk elements such as Fe, Mg, Al, and Si. Normalized Pb signals show a clear association to Fe coatings at the surface of the particles.


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