Are Iron-Rich Sedimentary Rocks the Key to the Spike in Orogenic Gold Mineralization in the Paleoproterozoic?

2011 ◽  
Vol 106 (3) ◽  
pp. 321-330 ◽  
Author(s):  
A. Lambeck ◽  
T. P. Mernagh ◽  
L. Wyborn
Keyword(s):  
Gold Mineralization ◽  
Sedimentary Rocks ◽  
Orogenic Gold ◽  
Orogenic Gold Mineralization

scholarly journals Scheme of mineral facies of metamorphic rocks and its application to the Fennoscandian shield with representative sites of orogenic gold mineralization

2015 ◽  
pp. 3
Author(s):  
Сергей Алексеевич Бушмин ◽  
Виктор Андреевич Глебовицкий ◽  
Sergey Bushmin ◽  
Viktor Glebovitsky
Keyword(s):  
Gold Mineralization ◽  
Fennoscandian Shield ◽  
Orogenic Gold ◽  
Metamorphic Rocks ◽  
Orogenic Gold Mineralization

The Role of a Transcrustal Shear Zone in Orogenic Gold Mineralization at the Ajjanahalli Mine, Dharwar Craton, South India

2004 ◽  
Vol 99 (4) ◽  
pp. 743-759 ◽  
Author(s):  
J. Kolb ◽  
A. Hellmann ◽  
A. Rogers ◽  
S. Sindern ◽  
T. Vennemann ◽  
...  
Keyword(s):  
Shear Zone ◽  
South India ◽  
Gold Mineralization ◽  
Dharwar Craton ◽  
Orogenic Gold ◽  
Orogenic Gold Mineralization

The Geology and Mineralogy of the Loulo Mining District, Mali, West Africa: Evidence for Two Distinct Styles of Orogenic Gold Mineralization

2013 ◽  
Vol 108 (2) ◽  
pp. 199-227 ◽  
Author(s):  
D. M. Lawrence ◽  
P. J. Treloar ◽  
A. H. Rankin ◽  
P. Harbidge ◽  
J. Holliday
Keyword(s):  
West Africa ◽  
Gold Mineralization ◽  
Orogenic Gold ◽  
Mining District ◽  
Orogenic Gold Mineralization

Hydrothermal Monazite and Xenotime Geochronology: A New Direction for Precise Dating of Orogenic Gold Mineralization

SEG Discovery ◽  
2003 ◽  
pp. 1-16 ◽  
Author(s):  
N. M. Vielreicher ◽  
D. I. Groves ◽  
I. R. Fletcher ◽  
N. J. McNaughton ◽  
B. Rasmussen
Keyword(s):  
Gold Mineralization ◽  
Orogenic Gold ◽  
Orogenic Gold Mineralization

Gold Deposits of the ~15-Moz Ahafo South Camp, Sefwi Granite-Greenstone Belt, Ghana: Insights into the Anatomy of an Orogenic Gold Plumbing System

2021 ◽  
Author(s):  
Quentin Masurel ◽  
Paul Morley ◽  
Nicolas Thébaud ◽  
Helen McFarlane
Keyword(s):  
Rock Mass ◽  
Shear Zone ◽  
Gold Mineralization ◽  
Hanging Wall ◽  
Spatial Association ◽  
Sedimentary Rocks ◽  
Shear Zones ◽  
Gold Deposits ◽  
Orogenic Gold ◽  
Plutonic Rocks

Abstract The ~15-Moz Ahafo South gold camp is located in southwest Ghana, the world’s premier Paleoproterozoic gold subprovince. Major orogenic gold deposits in the camp include Subika, Apensu, Awonsu, and Amoma. These deposits occur along an ~15-km strike length of the Kenyase-Yamfo shear zone, a major tectonostratigraphic boundary juxtaposing metamorphosed volcano-plutonic rocks of the Sefwi belt against metamorphosed volcano-sedimentary rocks of the Sunyani-Comoé basin. In this study, we document the geologic setting, structural geometry, and rheological architecture of the Ahafo South gold deposits based on the integration of field mapping, diamond drill core logging, 3-D geologic modeling, and the geologic interpretation of aeromagnetic data. At the camp scale, the Awonsu, Apensu, and Amoma deposits lie along strike from one another and share similar hanging-wall plutonic rocks and footwall volcano-sedimentary rocks. In contrast, the Subika gold deposit is hosted entirely in hanging-wall plutonic rocks. Steeper-dipping segments (e.g., Apensu, Awonsu, Subika) and right-hand flexures (e.g., Amoma, Apensu) in the Kenyase-Yamfo shear zone and subsidiary structures appear to have represented sites of enhanced damage and fluid flux (i.e., restraining bends). All gold deposits occur within structural domains bounded by discontinuous, low-displacement, sinistral N-striking tear faults oblique to the orogen-parallel Kenyase-Yamfo shear zone. At the deposit scale, ore-related hydrothermal alteration is zoned, with distal chlorite-sericite grading into proximal silica-albite-Fe-carbonate mineral assemblages. Alteration halos are restricted to narrow selvages around quartz-carbonate vein arrays in multiple stacked ore shoots at Subika, whereas these halos extend 30 to 100 m away from the ore zones at Apensu and Awonsu. There is a clear spatial association between shallow-dipping mafic dikes, mafic chonoliths, shear zones, and economic gold mineralization. The abundance of mafic dikes and chonoliths within intermediate to felsic hanging-wall plutonic host rocks provided rheological heterogeneity that favored the formation of enhanced fracture permeability, promoting the tapping of ore fluid(s). Our interpretation is that these stacked shallow-dipping mafic dike arrays also acted as aquitards, impeding upward fluid flow within the wider intrusive rock mass until a failure threshold was episodically reached due to fluid overpressure, resulting in transient fracture-controlled upward propagation of the ore-fluid(s). Our results indicate that high-grade ore shoots at Ahafo South form part of vertically extensive fluid conduit systems that are primarily controlled by the rheological architecture of the rock mass.

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