Comparative study of yttrium and rare-earth element behaviours in fluorine-rich hydrothermal fluids

1995 ◽  
Vol 119 (2-3) ◽  
pp. 213-223 ◽  
Author(s):  
Michael Bau ◽  
Peter Dulski
Keyword(s):  
Rare Earth ◽  
Comparative Study ◽  
Rare Earth Element ◽  
Earth Element ◽  
Hydrothermal Fluids

Multiple-stage hydrothermal alteration in porphyry copper systems in northern Turkey: the temporal interplay of potassic, propylitic, and phyllic fluids

1980 ◽  
Vol 17 (7) ◽  
pp. 901-926 ◽  
Author(s):  
R. P. Taylor ◽  
B. J. Fryer
Keyword(s):  
Rare Earth ◽  
Hydrothermal Alteration ◽  
Rare Earth Element ◽  
Earth Element ◽  
Root Zone ◽  
Porphyry Copper ◽  
Hydrothermal Fluids ◽  
New Mineral ◽  
Potassic Alteration ◽  
Different Levels

The Bakircay and Ulutas Cu–Mo prospects represent the first occurrences of porphyry mineralization to be described in Turkey.Differences observed in the two prospects in terms of hydrothermal alteration (in particular, alteration overprinting), igneous textures, abundance of xenoliths, breccia phenomena, and style and intensity of fracturing may relate to different levels of exposure within a model porphyry system, Bakircay representing the deep root zone of such a system and Ulutas reflecting much higher levels close to the apex of such a system, or may simply reflect different levels of emplacement.The alteration assemblages present at the Bakircay prospect lend themselves to a geochemical study of the temporal variations in the hydrothermal fluids responsible for single- and multiple-stage alteration–mineralization. The chemical changes involved during single-stage potassic alteration are related to amphibole breakdown and the deposition of hydrothermal biotite (and chalcopyrite). These changes are manifested in light rare-earth element (LREE) enrichment and heavy rare-earth element (HREE) depletion reflecting the high K+ and Cl− activity of the hydrothermal fluids. During propylitic overprinting of potassic alteration changes in whole-rock geochemistry relate to the destruction of biotite (both igneous and hydrothermal) and the formation of chlorite, epidote, calcite, and apatite. These changes result in the loss of ail rare-earth elements (REE) due to increasing fluid/rock ratios and further changes within the HREE relating to zircon stability and the deposition of new mineral phases, e.g., epidote. Conversion of preexisting alteration types lo the quartz–sericite–pyrite ± rutile, calcite assemblages, typical of phyllic alteration, results in the loss of all elements not accommodated in these phases. The high fluid/rock ratios and low pH of the fluids cause progressive leaching of all REE, particularly the lightest (La and Ce).

Geochemical implications of rare earth element patterns in hydrothermal fluids from mid-ocean ridges

1994 ◽  
Vol 58 (23) ◽  
pp. 5105-5113 ◽  
Author(s):  
G.P Klinkhammer ◽  
H Elderfield ◽  
J.M Edmond ◽  
A Mitra
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Hydrothermal Fluids ◽  
Ocean Ridges

scholarly journals The occurrence of wakefieldite, a rare earth element vanadate, in the rhyolitic Joe Lott Tuff, Utah, USA

2019 ◽  
Vol 84 (1) ◽  
pp. 109-116
Author(s):  
Bogusław Bagiński ◽  
Ray Macdonald ◽  
Harvey E. Belkin ◽  
Jakub Kotowski ◽  
Petras Jokubauskas ◽  
...  
Keyword(s):  
Solid Solution ◽  
Rare Earth ◽  
Rare Earth Element ◽  
Hydrothermal Fluid ◽  
Earth Element ◽  
Hydrothermal Fluids ◽  
Fe Oxide ◽  
Uranium Mineralisation ◽  
High Silica

AbstractThe high-silica rhyolitic Joe Lott Tuff was erupted at 19.2 ± 0.4 Ma from the Mount Belknap caldera, SW Utah. Certain units in the tuff contain two species of wakefieldite, the Nd- and Y-dominant types. They occur in disseminated streaks and patches in association with rhodochrosite, calcite, Fe oxide, cerite-(Ce), and a Mn silicate (caryopilite?), thought to have been deposited from hydrothermal fluids. The wakefieldites contain the highest levels of As (≤15.34 wt.% As2O5) and P (≤5.7 wt.% P2O5) yet recorded in this mineral, indicating significant solid solution towards chernovite-(Y) and xenotime-(Y). Thorium levels are also unusually high (≤14.2 wt.% ThO2). The source of the hydrothermal fluid(s) is unknown but might be related to uranium mineralisation in the region, in that As, V and U are commonly associated in such deposits.

scholarly journals Apatite Composition and U-Pb Geochronology from the Ptarmigan and Tom Deposits, NWT Canada; Implications for Petrogenesis

2021 ◽  
Author(s):  
Mark W. Richardson ◽  
Christopher R.M. McFarlane ◽  
David R. Lentz ◽  
Hendrik Falck
Keyword(s):  
Rare Earth ◽  
Rare Earth Element ◽  
Earth Element ◽  
Gold Deposits ◽  
Hydrothermal Fluids ◽  
Compositional Zoning ◽  
Eu Anomaly ◽  
Shaped Pattern ◽  
Flat Pattern

The Ptarmigan and Tom mesothermal gold deposits are located 10 km to the northeast of the city of Yellowknife, Northwest Territories in northern Canada. Both gold deposits comprise a series of en echelon veins that are hosted within upper greenschist to lower amphibolite facies ~2630 Ma (peak) rocks. Supracrustal units across the craton are intruded by the ca. 2610–2605-Ma granodiorite, tonalite, monzodiorite, quartz diorite, and affiliated rocks of the Concession Suite. Hydrothermal apatite is a common accessory mineral in both mineralized and non-mineralized quartz veins in the metasedimentary host rocks that constitute the Ptarmigan and Tom deposits. This study characterizes and compares turbidite-hosted hydrothermal apatite from the Ptarmigan and Tom deposits, non-mineralized veins adjacent to the ore body, and magmatic apatite from proximal LCT-pegmatites. Using electron probe microanalyses (EPMA), laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS), micro-XRF, and cathodoluminescence (CL), the major, minor, and trace element abundances have been quantified and mapped. In addition to utilizing this data to determine if the chemistry of apatite can be used to constrain the source of hydrothermal fluids, the apparent age of the apatite is also evaluated utilizing in situ U-Pb dating. The distribution and abundance of major, minor, and trace elements from in situ recovered apatite were studied to characterize the nature of mineralizing fluids. Most apatite from mineralized and non-mineralized veins show different Mn, Sr, and Pb contents, as well as chondrite-normalized rare-earth element (REE) and Y abundance patterns. REEs display five unique chondrite-normalized patterns: (1) negative sloped pattern with slight negative Eu anomaly, (2) a flat pattern with a positive Eu anomaly, (3) a positive slope with a negative Eu anomaly, (iv) light rare earth element (LREE) depleted pattern with positive Eu anomaly, and (v) bell-shaped pattern with a negative Eu anomaly. The REE patterns reflect both the source of the auriferous hydrothermal fluids and, perhaps, co-precipitating mineral phases. Apatite from the Ptarmigan vein occurs with both: (1) a flat pattern with a positive Eu anomaly and (2) bell-shaped pattern with a negative Eu anomaly. The bell-shaped and flat patterns typify orogenic gold deposits. Vein-hosted apatite commonly displays compositional zoning with a characteristic yellow cathodoluminescence (CL) emission spectra with darker cores and brighter rims. The cores have lower REE, whereas the rims are notably higher in REE. It is thought that the darker cores in CL images reflect a transition from an early low REE hydrothermal fluid to one enriched in REE. The hydrothermal apatite age of 2585 ± 15 Ma is consistent with the intrusions of the 2605 and 2590 Ma two-mica granites of the Prosperous Suite and associated LCT pegmatites.

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