Nd and Sr isotope study of hydrothermal scheelite and host rocks at Omai, Guiana Shield: implications for ore fluid source and flow path during the formation of orogenic gold deposits

2000 ◽  
Vol 35 (4) ◽  
pp. 302-314 ◽  
Author(s):  
G. Voicu ◽  
M. Bardoux ◽  
R. Stevenson ◽  
M. Jébrak
Keyword(s):  
Gold Deposits ◽  
Flow Path ◽  
Orogenic Gold ◽  
Guiana Shield ◽  
Sr Isotope ◽  
Fluid Source ◽  
Orogenic Gold Deposits ◽  
Isotope Study ◽  
Host Rocks

scholarly journals Controls on the Distribution of Invisible and Visible Gold in the Orogenic Gold Deposits of the Yangshan Gold Belt, West Qinling Orogen, China

Minerals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 92 ◽  
Author(s):  
Nan Li ◽  
Jun Deng ◽  
David Groves ◽  
Ri Han
Keyword(s):  
Gold Deposits ◽  
Orogenic Gold ◽  
Published Data ◽  
Qinling Orogen ◽  
Gold Ores ◽  
West Qinling ◽  
Orogenic Gold Deposits ◽  
Calcite Veins ◽  
Host Rocks ◽  
West Qinling Orogen

Six orogenic gold deposits constitute the Yangshan gold belt in the West Qinling Orogen. Gold is mostly invisible in solid solution or in the sulfide lattice, with minor visible gold associated with stibnite and in quartz-calcite veins. Detailed textural and trace-element analysis of sulfides in terms of a newly-erected paragenetic sequence for these deposits, together with previously published data, demonstrate that early magmatic-hydrothermal pyrite in granitic dike host-rocks has much higher Au contents than diagenetic pyrite in metasedimentary host rocks, but lower contents of As, Au, and Cu than ore-stage pyrite. Combined with sulfur isotope data, replacement textures in the gold ores indicate that the auriferous ore-fluids post-dated the granitic dikes and were not magmatic-hydrothermal in origin. There is a strong correlation between the relative activities of S and As and their total abundances in the ore fluid and the siting of gold in the Yangshan gold ores. Mass balance calculations indicate that there is no necessity to invoke remobilization processes to explain the occurrence of gold in the ores. The only exception is the Py1-2 replacement of Py1m, where fluid-mediated coupled dissolution-reprecipitation reactions may have occurred to exchange Au between the two pyrite phases.

scholarly journals Linking Gold Systems to the Crust-Mantle Evolution of Archean Crust in Central Brazil

Minerals ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 944
Author(s):  
Jessica Bogossian ◽  
Anthony I. S. Kemp ◽  
Steffen G. Hagemann
Keyword(s):  
Gold Deposits ◽  
Orogenic Gold ◽  
Crustal Growth ◽  
Central Brazil ◽  
Orogenic Gold Deposits ◽  
Geological Evolution ◽  
Ore Mineralogy ◽  
Host Rocks ◽  
Hydrothermal Event

The Goiás Archean Block (GAB) in central Brazil is an important gold district that hosts several world-class orogenic gold deposits. A better comprehension of the crustal, tectono-magmatic, and metallogenic settings of the GAB is essential to accurately define its geological evolution, evaluate Archean crustal growth models, and target gold deposits. We present an overview of gold systems, regional whole-rock Sm-Nd analyses that have been used to constrain the geological evolution of the GAB, and augment this with new in situ zircon U-Pb and Hf-O isotope data. The orogenic gold deposits show variable host rocks, structural settings, hydrothermal alteration, and ore mineralogy, but they represent epigenetic deposits formed during the same regional hydrothermal event. The overprinting of metamorphic assemblages by ore mineralogy suggests the hydrothermal event is post-peak metamorphism. The metamorphic grade of the host rocks is predominantly greenschist, locally reaching amphibolite facies. Isotope-time trends support a Mesoarchean origin of the GAB, with ocean opening at 3000–2900 Ma, and reworking at 2800–2700 Ma. Crustal growth was dominated by subduction processes via in situ magmatic additions along lithospheric discontinuities and craton margins. This promoted a crustal architecture composed of young, juvenile intra-cratonic terranes and old, long-lived reworked crustal margins. This framework provided pathways for magmatism and fluids that drove the gold endowment of the GAB.

A Fluid Inclusion and Stable Isotope Study at the Loulo Mining District, Mali, West Africa: Implications for Multifluid Sources in the Generation of Orogenic Gold Deposits

2013 ◽  
Vol 108 (2) ◽  
pp. 229-257 ◽  
Author(s):  
D. M. Lawrence ◽  
P. J. Treloar ◽  
A. H. Rankin ◽  
A. Boyce ◽  
P. Harbidge
Keyword(s):  
Stable Isotope ◽  
Fluid Inclusion ◽  
West Africa ◽  
Gold Deposits ◽  
Orogenic Gold ◽  
Mining District ◽  
Orogenic Gold Deposits ◽  
Isotope Study ◽  
Stable Isotope Study

scholarly journals Discriminating fluid source regions in orogenic gold deposits using B-isotopes

2016 ◽  
Vol 194 ◽  
pp. 57-76 ◽  
Author(s):  
James S. Lambert-Smith ◽  
Alexander Rocholl ◽  
Peter J. Treloar ◽  
David M. Lawrence
Keyword(s):  
Gold Deposits ◽  
Orogenic Gold ◽  
Fluid Source ◽  
Orogenic Gold Deposits ◽  
Source Regions

scholarly journals The giant Jiaodong gold province: The key to a unified model for orogenic gold deposits?

2016 ◽  
Vol 7 (3) ◽  
pp. 409-417 ◽  
Author(s):  
David I. Groves ◽  
M. Santosh
Keyword(s):  
Gold Deposits ◽  
Unified Model ◽  
Orogenic Gold ◽  
Orogenic Gold Deposits

A metasedimentary source of gold in Archean orogenic gold deposits

Geology ◽  
2021 ◽  
Author(s):  
Iain K. Pitcairn ◽  
Nikolaos Leventis ◽  
Georges Beaudoin ◽  
Stephane Faure ◽  
Carl Guilmette ◽  
...  
Keyword(s):  
Sedimentary Rock ◽  
Sedimentary Rocks ◽  
Gold Deposits ◽  
Metamorphic Grade ◽  
Orogenic Gold ◽  
Metal Source ◽  
Main Metal ◽  
Metasedimentary Rocks ◽  
Orogenic Gold Deposits ◽  
Archean Orogenic Gold Deposits

The sources of metals enriched in Archean orogenic gold deposits have long been debated. Metasedimentary rocks, which are generally accepted as the main metal source in Phanerozoic deposits, are less abundant in Archean greenstone belts and commonly discounted as a viable metal source for Archean deposits. We report ultralow-detection-limit gold and trace-element concentrations from a suite of metamorphosed sedimentary rocks from the Abitibi belt and Pontiac subprovince, Superior Province, Canada. Systematic decreases in the Au content with increasing metamorphic grade indicate that Au was mobilized during prograde metamorphism. Mass balance calculations show that over 10 t of Au, 30,000 t of As, and 600 t of Sb were mobilized from 1 km3 of Pontiac subprovince sedimentary rock metamorphosed to the sillimanite metamorphic zone. The total gold resource in orogenic gold deposits in the southern Abitibi belt (7500 t Au) is only 3% of the Au mobilized from the estimated total volume of high-metamorphic-grade Pontiac sedimentary rock in the region (25,000 km3), indicating that sedimentary rocks are a major contributor of metals to the orogenic gold deposits in the southern Abitibi belt.

Genesis of orogenic-gold deposits in the Broken River Province, northeast Queensland

2005 ◽  
Vol 52 (6) ◽  
pp. 941-958 ◽  
Author(s):  
I. M. A. Vos ◽  
F. P. Bierlein ◽  
G. S. Teale
Keyword(s):  
Gold Deposits ◽  
Orogenic Gold ◽  
Orogenic Gold Deposits
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