Next Article in Journal
Physicochemical Parameters and Geochemical Features of Ore-Forming Fluids for Orogenic Gold Deposits Throughout Geological Time
Previous Article in Journal
Binding Properties of Mechanically Activated Nepheline Containing Mining Waste
Open AccessArticle

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

1
Mineral Resources Development Research Center, Korea Institute of Geoscience and Mineral Resources, Daejeon 34132, Korea
2
Department of Earth Environmental Science, Pukyong National University, Busan 48513, Korea
*
Author to whom correspondence should be addressed.
Minerals 2020, 10(1), 49; https://doi.org/10.3390/min10010049
Received: 1 November 2019 / Revised: 1 January 2020 / Accepted: 2 January 2020 / Published: 5 January 2020
(This article belongs to the Special Issue ICP-MS Analysis for Rare Earth Elements)
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. View Full-Text
Keywords: allanite-rich vein; LA-MC-ICP-MS; recrystallized zircon; Triassic metamorphism; tectonic evolution of the OMB allanite-rich vein; LA-MC-ICP-MS; recrystallized zircon; Triassic metamorphism; tectonic evolution of the OMB
Show Figures

Figure 1

MDPI and ACS Style

No, S.-G.; Park, M.-E. 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, 10, 49.

Show more citation formats Show less citations formats
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Article Access Map by Country/Region

1
Back to TopTop