Genetic Environments at the Ssangjeon Tungsten-bearing Hydrothermal Vein Deposit

Sunjin Lee; Sang-Hoon Choi

doi:10.9719/EEG.2022.55.6.689

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Econ. Environ. Geol. 2022; 55(6): 689-699

Published online December 31, 2022

https://doi.org/10.9719/EEG.2022.55.6.689

Genetic Environments at the Ssangjeon Tungsten-bearing Hydrothermal Vein Deposit

Sunjin Lee, Sang-Hoon Choi^*

Author Info. +

Department of Earth and Environmental Sciences, Chungbuk National University, Cheongju, 28644, Republic of Korea

Correspondence to : ^*Corresponding author : cshoon@cbnu.ac.kr

Received: December 23, 2022; Revised: December 25, 2022; Accepted: December 25, 2022

This is an Open Access article distributed under the terms of the Creative Commons Attribution Non-Commercial License (http://creativecommons.org/licenses/by-nc/3.0) which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided original work is properly cited.

Abstract

The Ssangjeon tungsten deposit is located within the Yeongnam Massif. Within the area a number of hydrothermal quartz veins were formed by narrow open-space filling of parallel and subparallel fractures in the metasedimentary rocks as Wonnam formation, Buncheon granite gneiss, amphibolite and/or pegmatite. Mineral paragenesis can be divided into two stages (stage I, ore-bearing quartz vein; stage II, barren quartz vein) by major tectonic fracturing. Stage I, at which the precipitation of major ore minerals occurred, is further divided into three substages (early, middle and late) with paragenetic time based on minor fractures and discernible mineral assemblages: early, marked by deposition of arsenopyrite with pyrite; middle, characterized by introduction of wolframite and scheelite with Ti-Fe-bearing oxides and base-metal sulfides; late, marked by Bi-sulfides.
Fluid inclusion data show that stage I ore mineralization was deposited between initial high temperatures (≥370°C) and later lower temperatures (≈170°C) from H₂O-CO₂-NaCl fluids with salinities between 18.5 to 0.2 equiv. wt. % NaCl of Ssangjeon hydrothermal system. The relationship between salinity and homogenization temperature indicates a complex history of boiling, fluid unmixing (CO₂ effervescence), cooling and dilution via influx of cooler, more dilute meteoric waters over the temperature range ≥370°C to ≈170°C. Changes in stage I vein mineralogy reflect decreasing temperature and fugacity of sulfur by evolution of the Ssangjeon hydrothermal system with increasing paragenetic time.

Keywords Ssangjeon, tungsten, hydrothermal fluid, vein deposit, H₂O-CO₂-NaCl system

쌍전 함 텅스텐 열수 맥상광상의 생성환경

이선진 · 최상훈^*

충북대학교 지구환경과학과

요 약

쌍전광상은 영남육괴 선캠브리아기 변성퇴적암류인 원남층, 분천 화강편마암, 각섬암 또는 페그마타이트 내 열극을 충전하여 생성된 함 텅스텐 열수 맥상광상이다. 쌍전광상의 맥상 광화작용은 지구조적 운동(tectonic break)에 의하여 광화 1기(stage I)와 광화 2기(stage II)로 구분된다. 광화 1기는 석영맥의 생성과 함께 주된 함 텅스텐 광물인 철망간중석 및 회중석과 함께 황화광물 및 산화광물 등이 수반 산출한 시기로서, 공생관계와 광물조합 특성 등에 의하여 세 단계의 광화시기(초기, 중기, 후기)로 구분된다. 광화 1기의 초기에는 유비철석과 황철석이 산출되었다. 중기에는 주된 텅스텐 광화작용이 진행되어 철망간중석, 회중석과 함께 함 티탄 산화광물과 천금속 황화광물 등이 산출되었다. 후기에는 함 비스무트 광물과 함께 2차 광물인 백철석 등이 산출되었다. 광화 2시기는 주 광화작용 이후의 금속 광화작용이 이루어지지 않은 석영맥의 생성 시기이다.
쌍전광상의 주된 광화작용은 고온(≥370℃)의 H₂O-CO₂-NaCl계 열수유체 유입으로 시작되어 초기 내지 중기의 냉각과 비등작용 및 불혼화용융, 후기의 상대적으로 천부를 순환한 열수유체 또는 천수의 혼입 등에 의하여 ≥370℃~≤170℃의 온도 조건에서 18.5 to 0.2 wt. percent NaCl 상당 염농도를 갖는 유체에서 진행되었다. 쌍전광상의 광물 공생관계 변화는 이러한 열수계의 진화에 의한 온도와 황 분압 조건의 감소 등의 환경변화가 반영된 결과이다.

주요어 쌍전광상, 텅스텐, 열수, 맥상광상, H2O-CO2-NaCl계

Article

Research Paper

Econ. Environ. Geol. 2022; 55(6): 689-699

Published online December 31, 2022 https://doi.org/10.9719/EEG.2022.55.6.689

Genetic Environments at the Ssangjeon Tungsten-bearing Hydrothermal Vein Deposit

Sunjin Lee, Sang-Hoon Choi^*

Department of Earth and Environmental Sciences, Chungbuk National University, Cheongju, 28644, Republic of Korea

Correspondence to:^*Corresponding author : cshoon@cbnu.ac.kr

Received: December 23, 2022; Revised: December 25, 2022; Accepted: December 25, 2022

Abstract

Keywords Ssangjeon, tungsten, hydrothermal fluid, vein deposit, H₂O-CO₂-NaCl system

쌍전 함 텅스텐 열수 맥상광상의 생성환경

이선진 · 최상훈^*

충북대학교 지구환경과학과

Received: December 23, 2022; Revised: December 25, 2022; Accepted: December 25, 2022

요 약

주요어 쌍전광상, 텅스텐, 열수, 맥상광상, H2O-CO2-NaCl계

Fig 1.

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Figure 1.Geological map of the Ssangjeon deposit area(from KORES, 2011) with simplified geologic map of Korea (right side) showing the tectonic province and location of the Ssangjeon deposit.

Economic and Environmental Geology 2022; 55: 689-699https://doi.org/10.9719/EEG.2022.55.6.689

Fig 2.

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Figure 2.Photographs of the hand specimens at Ssnagjeon deposit. The lower photographs (in B and C) is under uv-lamp to observe tungsten-bearing minerals. Scale bar is 2cm. Abbreviations: qtz=quartz, sch=scheelite, sul=sulfides, wf=wolframite.

Economic and Environmental Geology 2022; 55: 689-699https://doi.org/10.9719/EEG.2022.55.6.689

Fig 3.

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Figure 3.Mineral paragenesis of the Ssangjeon deposit.

Economic and Environmental Geology 2022; 55: 689-699https://doi.org/10.9719/EEG.2022.55.6.689

Fig 4.

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Figure 4.Photomicrographs of the mineral occurrence and assemblages at the Ssangjeon deposit. Abbreviations: asp=arsenopyrite, bn=bismuthinite, cp=chalcopyrite, gd=glaucodot, im=ilmenite, mar=marcasite, nb=native bismuth, po=pyrrhotitie, py=pyrite, qtz=quartz, sch=scheelite, sl=sphalerite, tt=titanite, wf=wolframite.

Economic and Environmental Geology 2022; 55: 689-699https://doi.org/10.9719/EEG.2022.55.6.689

Fig 5.

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Figure 5.Photomicrographs of type I(liquid-rich fluid inclusions: A), type II(vapor-rich fluid inclusions: B), type IVa(CO₂-bearing fluid inclusions: D) and ype IVb(CO₂-bearing fluid inclusions: C) fluid inclusions in vein quartz, Ssangjeon deposit. Abbreviations: V=vapor phase, L=liquid phase, aq=aqueous.

Economic and Environmental Geology 2022; 55: 689-699https://doi.org/10.9719/EEG.2022.55.6.689

Fig 6.

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Figure 6.Histogram of homogenization temperatures(Th) of primary fluid inclusions in vein quartz of the Ssangjeon deposit. Abbreviations: Type I=type I fluid inclusion, Type II=type IIincludion, Type IVa=type IVa fluid inclusion (homogenized by CO₂-liquid), Type IVb=type IVb fluid inclusion (homogenized by aqueous liquid).

Economic and Environmental Geology 2022; 55: 689-699https://doi.org/10.9719/EEG.2022.55.6.689

Fig 7.

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Figure 7.Histogram of salinities of primary fluid inclusions in vein quartz of the Ssangjeon deposit. Abbreviations are same as Figure 6.

Economic and Environmental Geology 2022; 55: 689-699https://doi.org/10.9719/EEG.2022.55.6.689

Fig 8.

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Figure 8.Homogenization temperature versus salinity diagram for primary type I, II, IVa and IVb fluid inclusions in vein quartz of the Ssangjeon deposit.

Economic and Environmental Geology 2022; 55: 689-699https://doi.org/10.9719/EEG.2022.55.6.689

Fig 9.

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Figure 9.Pseudo-binary condensed T-X_As section of the Fe-As-S system (Kretschmar and Scott, 1976). Filled triangles and inverted triangles indicate As contents in arsenopyrite, Ssangjeon deposit. Black bold line demonstrates As contents in arsenopyrite(with pyrrhotitie and/or pyrite) in Ssangjeon W-bearing deposit. Abbreviations: asp=arsenopyrite, Lo=loellingite, po=pyrrhotite, py=pyrite.

Economic and Environmental Geology 2022; 55: 689-699https://doi.org/10.9719/EEG.2022.55.6.689

Fig 10.

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Figure 10.Fugacity of Sulfur versus temperature diagram for stage I of the Ssangjeon W-bearing deposit showing the possible sulfur fugacity and temperature ranges with sulfidation reactions. Abbreviations: asp=arsenopyrite, Bi=native bismuth, bn=bismuthinite, hm=hematite, mt=magnetite, po=pyrrhotite, py=pyrite.

Economic and Environmental Geology 2022; 55: 689-699https://doi.org/10.9719/EEG.2022.55.6.689

Table 1 . Chemical composition of arsenopyrite from the Ssangjeon W deposit.

Sample no.	wt. %					atomic %
Sample no.	Fe	As	Cu	S	Total	Fe	As	S	Total
J8	34.8	44.1	0.0	20.5	99.3	33.5	31.9	34.6	100.0
	34.3	46.4	0.0	18.7	99.4	33.5	34.1	32.4	100.0
	35.1	45.5	0.0	19.6	100.2	34.1	33.0	33.0	100.0
	35.2	45.1	0.0	19.9	100.2	34.1	32.4	33.5	100.0
J18-3	34.9	45.4	0.0	19.9	100.2	33.5	33.0	33.5	100.0
	34.5	45.6	0.0	19.7	99.8	33.5	33.0	33.5	100.0
J3-1	33.7	45.1	0.0	20.2	99.0	32.8	32.8	34.4	100.0
	35.3	42.0	0.0	22.3	99.5	33.3	29.6	37.0	100.0
	34.7	42.5	0.0	22.4	99.6	32.8	30.2	37.0	100.0
J18-2-1	34.7	44.4	0.0	19.8	98.9	33.9	32.2	33.9	100.0
J18-2-2	34.0	45.0	0.3	20.2	99.6	33.2	32.6	34.2	100.0
J18-2-3	34.9	43.1	1.0	21.6	100.6	33.5	30.3	36.2	100.0

Table 2 . Chemical composition of sphalerite from the Ssangjeon W deposit.

Sample no.	weight. %					atomic %
Sample no.	Zn	Fe	Cd	S	Total	ZnS	FeS	CdS	Total
J8	62.5	2.9	2.0	33.2	100.6	93.2	4.9	1.9	100.0
J18-2-1	66.5	2.1	0.5	33.4	102.5	96.2	3.8	0.0	100.0
	64.2	2.6	0.6	33.4	100.7	95.2	4.9	0.0	100.1
J18-2-2	62.8	3.2	0.6	33.4	100.0	93.2	5.8	1.0	100.0
	64.0	2.7	0.6	33.0	100.3	94.2	4.8	1.0	100.0
	63.2	3.2	0.6	33.3	100.3	93.3	5.8	1.0	100.1
	63.9	2.6	0.6	33.3	100.4	94.2	4.8	1.0	100.0

Dec 31, 2024 Vol.57 No.6, pp. 665~835

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Genetic Environments at the Ssangjeon Tungsten-bearing Hydrothermal Vein Deposit

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쌍전 함 텅스텐 열수 맥상광상의 생성환경

요 약

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Research Paper

Genetic Environments at the Ssangjeon Tungsten-bearing Hydrothermal Vein Deposit

Abstract

쌍전 함 텅스텐 열수 맥상광상의 생성환경

요 약

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