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Differentiating between hydrothermal and diagenetic carbonate using rare earth element and yttrium (REE+Y) geochemistry: a case study from the Paleoproterozoic George Fisher massive sulfide Zn deposit, Mount Isa, Australia
- Source :
- Mineralium Deposita
- Publication Year :
- 2021
- Publisher :
- Springer Science and Business Media LLC, 2021.
-
Abstract
- Carbonate minerals are ubiquitous in most sediment-hosted mineral deposits. These deposits can contain a variety of carbonate types with complex paragenetic relationships. When normalized to chondritic values (CN), rare-earth elements and yttrium (REE+YCN) can be used to constrain fluid chemistry and fluid-rock interaction processes in both low- and high-temperature settings. Unlike other phases (e.g., pyrite), the application of in situ laser ablation-inductively coupled plasma-mass spectroscopy (LA-ICP-MS) data to the differentiation of pre-ore and hydrothermal carbonates remains relatively untested. To assess the potential applicability of carbonate in situ REE+Y data, we combined transmitted light and cathodoluminescence (CL) petrography with LA-ICP-MS analysis of carbonate mineral phases from (1) the Proterozoic George Fisher clastic dominated (CD-type) massive sulfide deposit and from (2) correlative, barren host rock lithologies (Urquhart Shale Formation). The REE+YCN composition of pre-ore calcite suggests it formed during diagenesis from diagenetic pore fluids derived from ferruginous, anoxic seawater. Hydrothermal and hydrothermally altered calcite and dolomite from George Fisher is generally more LREE depleted than the pre-ore calcite, whole-rock REE concentrations, and shale reference values. We suggest this is the result of hydrothermal alteration by saline Cl--rich mineralizing fluids. Furthermore, the presence of both positive and negative Eu/Eu* values in calcite and dolomite indicates that the mineralizing fluids were relatively hot (>250°C) and cooled below 200–250°C during ore formation. This study confirms the hypothesis that in situ REE+Y data can be used to differentiate between pre-ore and hydrothermal carbonate and provide important constraints on the conditions of ore formation.<br />Helmholtz-Gemeinschaft http://dx.doi.org/10.13039/501100001656<br />https://doi.org/10.5880/GFZ.3.1.2020.005
- Subjects :
- 010504 meteorology & atmospheric sciences
Dolomite
Geochemistry
Carbonate minerals
engineering.material
Mount Isa
010502 geochemistry & geophysics
01 natural sciences
Hydrothermal circulation
Petrography
chemistry.chemical_compound
CD-type massive sulfide deposit
Geochemistry and Petrology
500 Naturwissenschaften und Mathematik::550 Geowissenschaften, Geologie::550 Geowissenschaften
LA-ICP-MS
Rare earth elements
0105 earth and related environmental sciences
Calcite
Mineral
Proterozoic
Geophysics
ddc:553.4
chemistry
engineering
Carbonate
Economic Geology
Pyrite
Carbonate chemistry
Geology
Subjects
Details
- ISSN :
- 14321866 and 00264598
- Volume :
- 57
- Database :
- OpenAIRE
- Journal :
- Mineralium Deposita
- Accession number :
- edsair.doi.dedup.....69f06a63799e94e4aae5cf102d4a2519