scholarly journals Rare earth elements in hydrothermal fluids from Kueishantao, off northeastern Taiwan: Indicators of shallow-water, sub-seafloor hydrothermal processes

2013 ◽  
Vol 58 (32) ◽  
pp. 4012-4020 ◽  
Author(s):  
XiaoYuan Wang ◽  
ZhiGang Zeng ◽  
Shuai Chen ◽  
XueBo Yin ◽  
Chen-Tung Arthur Chen
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Shallow Water ◽  
Hydrothermal Fluids ◽  
Hydrothermal Processes

scholarly journals Rare Earth Elements in Mineral Deposits: Speciation in Hydrothermal Fluids and Partitioning in Calcite

Geofluids ◽  
2018 ◽  
Vol 2018 ◽  
pp. 1-19 ◽  
Author(s):  
Emily P. Perry ◽  
Alexander P. Gysi
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Hydrothermal Fluids ◽  
Mineral Deposits ◽  
Chloride Complexes ◽  
Natural Systems ◽  
Low Salinity ◽  
Numerical Predictions ◽  
Hydrothermal Processes ◽  
Bayan Obo

Studying the speciation and mineral-fluid partitioning of the rare earth elements (REE) allows us to delineate the key processes responsible for the formation of economic REE mineral deposits in natural systems. Hydrothermal REE-bearing calcite is typically hosted in carbonatites and alkaline rocks, such as the giant Bayan Obo REE deposit in China and potential REE deposits such as Bear Lodge, WY. The compositions of these hydrothermal veins yield valuable information regarding pressure (P), temperature (T), salinity, and other physicochemical conditions under which the REE can be fractionated and concentrated in crustal fluids. This study presents numerical simulation results of the speciation of REE in aqueous NaCl-H2O-CO2-bearing hydrothermal fluids and a new partitioning model between calcite and fluids at different P-T-x conditions. Results show that, in a high CO2 and low salinity system, bicarbonate/carbonate are the main transporting ligands for the REE, but predominance shifts to chloride complexes in systems with high CO2 and high salinity. Hydroxyl REE complexes may be important for the solubility and transport of the REE in alkaline fluids. These numerical predictions allow us to make quantitative interpretations of hydrothermal processes in REE mineral deposits, particularly in carbonatites, and show where future experimental work will be essential in improving our modeling capabilities for these ore-forming processes.

scholarly journals Allanite Geochemical Response to Hydrothermal Alteration by Alkaline, Low-Temperature Fluids

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 392 ◽  
Author(s):  
Katarzyna Gros ◽  
Ewa Słaby ◽  
Petras Jokubauskas ◽  
Jiří Sláma ◽  
Gabriela Kozub-Budzyń
Keyword(s):  
Rare Earth ◽  
Low Temperature ◽  
Rare Earth Elements ◽  
Geochemical Evolution ◽  
Additional Component ◽  
Second Stage ◽  
Ce Anomaly ◽  
Hydrothermal Processes ◽  
Fluid Infiltration ◽  
Two Stages

Allanite is one of the main rare earth elements (REE)-rich accessory minerals in composite dykes from the granitoid pluton of Karkonosze. These dykes differ in composition from the bulk of the pluton by elevated rare earth elements (REE), Y, Zr, and alkali contents, suggesting contribution of an additional component. Allanite exhibits complex alteration textures, which can be divided into two stages. The first stage is represented by allanite mantles, formed by fluid infiltration into previously crystallized magmatic allanite. These zones have low totals, are Ca-, Al-, Mg-, and light REE (LREE)-depleted, and Y-, heavy REE (HREE)-, Th-, Ti-, and alkali-enriched. The fractionation between LREE and HREE was caused by different mobility of complexes formed by these elements in aqueous fluids. The second stage includes recrystallized LREE-poor, Y-HREE-rich allanite with variable Ca, Al, Mg, and REE-fluorocarbonates. The alteration products from both stages demonstrate higher Fe3+/(Fe2+ + Fe3+) ratios and a negative Ce anomaly. These features point to the alkaline, low-temperature, and oxidized nature of the fluids. The differences in mobility and solubility of respective ligands show that the fluids from the first stage may have been dominated by Cl, whereas those of the second stage may have been dominated by F and CO2 (and PO4 in case of one sample). The inferred chemistry of the fluids resembles the overall geochemical signature of the composite dykes, indicating a major contribution of the hydrothermal processes to their geochemical evolution.

scholarly journals Rare earth elements as indicators of hydrothermal processes within the East Scotia subduction zone system

2014 ◽  
Vol 140 ◽  
pp. 20-38 ◽  
Author(s):  
Catherine S. Cole ◽  
Rachael H. James ◽  
Douglas P. Connelly ◽  
Ed C. Hathorne
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Subduction Zone ◽  
Hydrothermal Processes

scholarly journals Significance of Calcite Trace Elements Contents and C-O Isotopic Compositions for Ore-Forming Fluids and Gold Prospecting in the Zhesang Carlin-Like Gold Deposit of Southeastern Yunnan, China

Minerals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 338
Author(s):  
Jiasheng Wang ◽  
Jinyang Chang ◽  
Chao Li ◽  
Zhenchun Han ◽  
Tao Wang ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Gold Deposit ◽  
Meteoric Water ◽  
Gold Mineralization ◽  
Mining Area ◽  
Gold Deposits ◽  
Hydrothermal Fluids ◽  
Magmatic Fluid ◽  
Isotopic Compositions

The Zhesang gold deposit of southeastern Yunnan is an important component of the Dian-Qian-Gui (Yunnan, Guizhou, and Guangxi) “Golden Triangle”, which hosts a multitude of Carlin-like gold deposits (CLGDs). Calcite is one of the most common gangue minerals in Zhesang. The calcites that have been found in the mining area are classified as ore-stage and post-ore calcites. The ore-stage calcite exhibits a clear paragenetic relationship with gold-bearing arsenopyrite and with an alteration halo that has been cut by the post-ore calcite. To elucidate the origin of the ore-forming fluids of the Zhesang gold deposit and to investigate the possibility of utilizing calcite geochemistry as prospecting indicators, the rare earth elements (REEs), Y, Fe, Mn and Mg contents, and C-O isotopic compositions of calcites from Zhesang have been analyzed. The ore-stage calcite is enriched in middle rare earth elements (MREEs) relative to light rare earth elements (LREEs) and heavy rare earth elements (HREEs) (MREE/LREE = 1.11–1.61, MREE/HREE = 6.12–8.22), whereas post-ore calcite exhibits an enrichment in LREE (LREE/HREE = 4.39–14.93, MREE/LREE = 0.35–0.71). The ore-stage and post-ore calcites were both formed by hydrothermal fluids; however, these hydrothermal fluids may have different sources. The Fe contents of the ore-stage calcite are significantly higher than those of post-ore calcite (4690–6300 μg/g versus 2030–2730 μg/g). Ore-stage calcite also has significantly lower δ18OV-SMOW values than post-ore calcite (11.03–12.49‰ versus 16.48–17.14‰). These calcites with an MREE/LREE ratio greater than 0.92, MREE/HREE ratio greater than 5.69, Fe content greater than 3827 μg/g, and δ18OV-SMOW value less than 14.40‰ represent ore-stage calcites and are important prospecting guidelines. According to the REE, C-O isotopic characteristics of the calcites and the previous findings, it is inferred that the ore-forming fluids of the Zhesang gold deposit were a mixture of crustal fluid by meteoric water leaching wall rocks and a small amount of basic magmatic fluid. The formation of post-ore calcite might be derived from meteoric water and marine carbonates interaction. The ore-forming fluids of the Zhesang gold deposit may be associated with the intrusion of diabase that outcrops in the mining area, and that the basic magmatic activities of the Indosinian period also provided some of the ore-forming materials and heat for gold mineralization.

scholarly journals Carbonatites from the Southern Brazilian platform: I

2020 ◽  
Vol 12 (1) ◽  
pp. 452-478
Author(s):  
Sergio Speziale ◽  
Francesca Castorina ◽  
Paolo Censi ◽  
Celso de Barros Gomes ◽  
Leila Soares Marques ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Hydrothermal Fluids ◽  
Evolutionary Trend ◽  
Compelling Evidence ◽  
Isotopic Data ◽  
Comprehensive Overview ◽  
Element Abundances ◽  
Compositional Variability ◽  
Formation And Evolution

AbstractWe present a comprehensive overview of the geochemical characteristics and evolution of the carbonatites from the southern Brazilian Platform (Paraná Basin). The carbonatites from different complexes display large compositional variability in terms of abundances of incompatible and rare earth elements. This is in agreement with an origin from heterogeneous lithospheric sources, as confirmed by isotopic data (see Speziale et al., this issue). The characteristic major and trace element abundances of these carbonatites present compelling evidence for invoking liquid unmixing as the main mechanism of their formation and evolution albeit few exceptions. We propose an evolutionary trend for the Brazilian carbonatites, which can be summarized as following: exsolution of the primary Ca- or Mg-carbonatitic liquids systematically takes place at the phonolite-peralkaline phonolite stage of magma differentiation; this is followed by progressive Fe-enrichment and by final emplacement of fluorocarbonatites associated with hydrothermal fluids.

Contrasting Geochemistry of Apatite from Peridotites and Sulfide Ores of the Jinchuan Ni-Cu Sulfide Deposit, NW China

2021 ◽  
Author(s):  
Mei-Yu Liu ◽  
Mei-Fu Zhou ◽  
Shang-Guo Su ◽  
Xue-Gen Chen
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Limit Of Detection ◽  
Sulfide Minerals ◽  
Hydrothermal Fluids ◽  
Sulfide Deposit ◽  
Volatile Components ◽  
Sulfide Ores ◽  
Sulfide Ore

Abstract Apatite is present within both the hosting lherzolite and sulfide ore at the Jinchuan magmatic Ni-Cu sulfide deposit of northwest China. Apatite grains within the lherzolite are generally large and hexagonal (>200 μm) and are associated with interstitial phlogopite and amphibole. These apatite grains contain ~0.9 wt % F, ~1 wt % Cl, 6,800 to 14,500 ppm rare earth elements (REE) and have in situ δ18OV-SMOW values of 5.10 to 6.38‰, all of which are indicative of crystallization from an evolved silicate magma. In comparison, the massive and disseminated sulfide ores contain fine-grained apatite (<200 μm) that is associated with sulfide minerals, phlogopite, and albite. These apatite grains contain sulfide inclusions that are indicative of crystallization almost coevally with or slightly later than the sulfide minerals. They are Cl-rich apatite with an average Cl of 5.6 wt % but F concentrations are below the limit of detection. They contain 1,860 to 2,300 ppm REE and have in situ δ18OV-SMOW values of 5.62 to 6.47‰. These data suggest that the sulfide-associated apatite formed from F- and REE-depleted, Cl-bearing sulfide melts. The apatite within the lherzolite was overprinted by later hydrothermal fluids as evidenced by the presence of abundant rounded and needle-like monazite and rare allanite inclusions within the apatite that formed as a result of a coupled metasomatism-reprecipitation process shortly after crystallization. Altered and fresh apatite domains have similar δ18O values, suggesting that this alteration was induced by postmagmatic hydrothermal fluids. The apatite within the lherzolite and sulfide ore crystallized from two conjugate immiscible silicate and sulfide melts, respectively. Rare earth elements and F were preferentially partitioning into silicate melts, whereas most volatile components were mainly partitioned into the sulfide melts. The silicate magmas from which apatite crystallized were rich in light REE (LREE) relative to heavy REE (HREE). Volatile components in the sulfide melts changed the physicochemical conditions to enable such high-density melts to migrate upward and finally settle in the shallow chamber with silicate rocks.

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