Rare earth element metasomatism in hydrothermal systems: the Willsboro-Lewis wollastonite ores, New York, USA

1998 ◽  
Vol 62 (17) ◽  
pp. 2965-2977 ◽  
Author(s):  
Philip R. Whitney ◽  
James F. Olmsted
Keyword(s):  
New York ◽  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Hydrothermal Systems

scholarly journals Integrated geophysical imaging of rare-earth-element-bearing iron oxide-apatite deposits in the eastern Adirondack Highlands, New York

Geophysics ◽  
2020 ◽  
pp. 1-64
Author(s):  
Anjana K. Shah ◽  
Ryan D. Taylor ◽  
Gregory J. Walsh ◽  
Jeffrey D. Phillips
Keyword(s):  
New York ◽  
Rare Earth ◽  
Iron Oxide ◽  
Rare Earth Element ◽  
Hydrothermal System ◽  
Host Rock ◽  
Earth Element ◽  
Magnetic Data ◽  
Surface Geology ◽  
Radiometric Data

The eastern Adirondack Highlands of northern New York host dozens of iron oxide-apatite (IOA) deposits containing magnetite and rare earth element (REE)-bearing apatite. We use new aeromagnetic, aeroradiometric, ground gravity, and sample petrophysical and geochemical data to image and understand these deposits and their geologic framework. Aeromagnetic total field data reflect highly magnetic leucogranite host rock and major structures that likely served as fluid conduits for the hydrothermal system. Bandpass filtering of the aeromagnetic data reveals individual deposits that were verified in the field or from historical records. A three-dimensional inversion for magnetic susceptibility images these deposits at depth, allowing inference of plunge directions and relative size. Radiometric data highlight variations in the surface geology and several large tailings piles that contain REE-bearing apatite. Within the host rock, eTh (equivalent Th), K and the eTh/K ratio are variable with high eTh/K near several of the IOA deposits. Areas with elevated K or low eTh/K representing potassic alteration appear to be rare; instead elevated eTh/K ratios likely reflect widespread sodic alteration overprinting potassic alteration. Bouguer gravity anomalies show limited correspondence to the surface geology, radiometric data, or magnetic data, but do exhibit ~10-km wide highs in areas where deposits are observed. Two-dimensional forward models of the gravity and magnetic data show that deeper dense material beneath the leucogranite is quantitatively feasible. If these dense rocks represent intrusions that were emplaced or still cooling at the time of mineralization, they may have served as a heat source that helped to drive the hydrothermal system. Combining datasets, we find that deposits occur towards the distal ends of major structures within the host leucogranite and mostly above gravity highs. The geophysical modeling thus suggests that IOA deposits formed in structural, thermal, and chemical traps near the distal ends of the hydrothermal system.

Geochemistry and Geophysics of Iron Oxide-Apatite Deposits and Associated Waste Piles with Implications for Potential Rare Earth Element Resources from Ore and Historical Mine Waste in the Eastern Adirondack Highlands, New York, USA

2019 ◽  
Vol 114 (8) ◽  
pp. 1569-1598
Author(s):  
Ryan D. Taylor ◽  
Anjana K. Shah ◽  
Gregory J. Walsh ◽  
Cliff D. Taylor
Keyword(s):  
New York ◽  
Rare Earth ◽  
Iron Oxide ◽  
Rare Earth Element ◽  
Earth Element ◽  
Granite Gneiss ◽  
Geochemical Data ◽  
Published Data ◽  
Data Set ◽  
Ore Formation

Abstract The iron oxide-apatite (IOA) deposits of the eastern Adirondack Highlands, New York, are historical high-grade magnetite mines that contain variable concentrations of rare earth element (REE)-bearing apatite crystals. The majority of the deposits are hosted within sodically altered Lyon Mountain granite gneiss, although some deposits occur within paragneiss, gabbro, anorthosite, or potassically altered Lyon Mountain granite gneiss. The IOA deposits and the waste and/or tailings piles associated with them have potential as an unconventional resource for REEs. Reprocessing of these piles would have the advantage of partial recycling of the waste material to produce a set of critical elements. Thirty-four ore, nine rock, 25 waste-pile, and four tailings-pile samples were collected and analyzed for major, minor, and trace elements. At the tailings- and waste-pile sites, composite samples were collected by combining 30 to >50 subsamples randomly distributed over each pile. The total REE content of the waste and tailings piles varied from approximately 10 to 22,000 ppm, whereas the ore sample concentrations ranged from approximately 15 to 48,000 ppm total REEs. A positive correlation exists between the total REE content of ore and its associated waste pile. Median light REE/heavy REE values were 2.14 for waste/tailings piles and 2.25 for ore, which is a substantial relative enrichment in the heavy REEs in comparison to many developed REE mines, such as the mined carbonatites of Bayan Obo, China, and Mountain Pass, California. Importantly, the ore and waste samples are significantly enriched in both Y and Nd compared to other REEs in the samples. Other minor components such as Th are also elevated. Airborne radiometric surveys show large positive eTh and eU anomalies corresponding to tailings piles. Although it is a limited data set, geochemical data of unaltered and altered host rocks suggest a speculative new model for IOA ore formation in the Adirondack Highlands that is consistent with the geology and previously published data. The ferroan ore-hosting Lyon Mountain granite gneiss underwent localized potassic alteration that enriched the altered rock in Fe, REEs, Th, and other metals. A later sodic alteration event affected the previously potassically altered Lyon Mountain granite gneiss, which increased rock porosity and remobilized Fe, REEs, and other elements from the host rock into the iron ore seams. The sodic fluids responsible for ore formation were enriched in F and Cl.

Geochemical features of major and rare-earth element behavior in the Paratunka and Bol’shebannyi hydrothermal systems of Kamchatka

2016 ◽  
Vol 10 (6) ◽  
pp. 458-475 ◽  
Author(s):  
O. V. Chudaev ◽  
G. A. Chelnokov ◽  
I. V. Bragin ◽  
N. A. Kharitonova ◽  
S. N. Rychagov ◽  
...  
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Hydrothermal Systems

scholarly journals Magmatic volatiles episodically flush oceanic hydrothermal systems as recorded by zoned epidote

2020 ◽  
Vol 1 (1) ◽  
Author(s):  
Stephen Fox ◽  
Yaron Katzir ◽  
Wolfgang Bach ◽  
Lucy Schlicht ◽  
Justin Glessner
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Hydrothermal Systems ◽  
Ore Deposits ◽  
Strontium Isotope ◽  
Magmatic Fluid ◽  
Oceanic Spreading ◽  
Magmatic Volatiles ◽  
Rock Alteration

AbstractCirculation of seawater at oceanic spreading centers extracts heat, drives rock alteration, and transports leached metals to shallower levels of the crust, where they may precipitate and form ore deposits. Crystallization of the lower crust, may exsolve and introduce magmatic volatiles into the seawater-dominant system. However, the role of magmatic volatiles added to the hydrothermal system, including pathways of these fluids are lesser known. Here we present coupled in-situ strontium isotope and rare earth element data of distinct domains in epidote, a common hydrothermal mineral throughout the Troodos ophiolite, to track magmatic fluid input and flow. Epidote crystal domains characterize three distinct strontium isotope-rare earth element signatures—suggesting sequential growth from magma-derived fluids (0.704, negative europium anomalies), rock-buffered fluids (0.7055, positive europium anomalies) and seawater-derived fluids (0.7065, negative cerium anomalies). Epidote records episodic fluxing of magmatic fluids from plagiogranites, through epidosites in the upflow zone and into metal ore deposits.

scholarly journals Quantifying metasomatic high-field-strength and rare-earth element transport from alkaline magmas

Geology ◽  
2021 ◽  
Author(s):  
Krzysztof Sokół ◽  
Adrian A. Finch ◽  
William Hutchison ◽  
Jonathan Cloutier ◽  
Anouk M. Borst ◽  
...  
Keyword(s):  
Rare Earth ◽  
Field Strength ◽  
Rare Earth Element ◽  
High Field ◽  
Earth Element ◽  
Chemical Interaction ◽  
Hydrothermal Systems ◽  
Initial Reaction ◽  
High Field Strength ◽  
Alkaline Magmas

Alkaline igneous rocks host many global high-field-strength element (HFSE) and rare-earth element (REE) deposits. While HFSEs are commonly assumed to be immobile in hydrothermal systems, transport by late-stage hydrothermal fluids associated with alkaline magmas is reported. However, the magnitude of the flux and the conditions are poorly constrained and yet essential to understanding the formation of REE-HFSE ores. We examined the alteration of country rocks (“fenitization”) accompanying the emplacement of a syenite magma at Illerfissalik in Greenland, through analysis of changes in rock chemistry, mineralogy, and texture. Our novel geochemical maps show a 400-m-wide intrusion aureole, within which we observed typically tenfold increases in the concentrations of many elements, including HFSEs. Textures suggest both pervasive and structurally hosted fluid flow, with initial reaction occurring with the protolith’s quartz cement, leading to increased permeability and enhancing chemical interaction with a mixed Ca-K-Na fenitizing fluid. We estimated the HFSE masses transferred from the syenite to the fenite by this fluid and found ~43 Mt of REEs were mobilized (~12% of the syenite-fenite system total rare-earth-oxide [TREO] budget), a mass comparable to the tonnages of some of the world’s largest HFSE resources. We argue that fenite can yield crucial information about the tipping points in magma evolution because retention and/or loss of volatile-bonded alkali and HFSEs are key factors in the development of magmatic zirconosilicate-hosted HFSE ores (e.g., Kringlerne, at Ilímaussaq), or the formation of the syenite-hosted Nb-Ta-REE (Motzfeldt-type) roof-zone deposits.

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