High-resolution microscopy of gold in unoxidized ore from the Carlin Mine, Nevada

Bakken, Barbara M.; Hochella, Michael F.; Marshall, A. F.; Turner, Alison

doi:10.2113/gsecongeo.84.1.171

Cited by 109 publications

(44 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Previous investigators (e.g., Cathelineau et al 1989;Bogosu Cabri et al 1989;Bakken et al 1989;Cook and Bogosu Chryssoulis 1990;Chryssoulis and Cabri 1990;Fleet et al Bogosu 1993) demonstrated that sub-microscopic gold exists in Bogosu Bogosu arsenopyrite and arsenian pyrite both in solid solution in Bogosu the crystal lattice and as discrete colloidal particles. Gold Bogosu was preferentially concentrated within As-rich zones of Bogosu arsenian pyrite (Fleet et al 1993) and in As-rich and Bogosu (Sb + Fe)-poor zones of arsenopyrite (Cathelineau et al Bogosu 1989).…”

mentioning

confidence: 96%

Gold mineralization in As-rich mesothermal gold ores of the Bogosu-Prestea mining district of the Ashanti Gold Belt, Ghana: remobilization of ?invisible? gold

1994

View full text Add to dashboard Cite

The Bogosu-Prestea mining district of southwestern Ghana is a 33 km section of the Early Proterozoic Ashanti Gold Belt. Greenschist facies carbonaceous and carbonate-bearing turbidites and greywackes, and mafic dikes host numerous economic mesothermal gold deposits. Structurally higher ores in the Bogosu concession have brittle deformation and consist of disseminated-sulphide lodes in tectonically-disrupted sedimentary rocks and carbonate-altered mafic dikes. Most gold occurs as micrometre-size particles in arsenian pyrite, and as "invisible" gold in arsenian pyrite and arsenopyrite. The structurally deeper ores of the adjoining Prestea concession are associated with brittle-ductile deformation and consist of extensive crack-seal quartz-veins and graphitic shear zones. Only minor amounts of "invisible" gold were detected; in these deeper lodes, gold occurs dominantly as abundant microscopic and larger particles in sulphide/arsenide minerals and in gangue. The gold distribution patterns revealed by SIMS microprobe analysis and ion maps, EMP and colour staining suggest that most of the primary gold in the Bogosu-Prestea system precipitated in solidsolution with sulphide/arsenide minerals. However, postdepositional concentration and redistribution occurred, in increasing degree with: 1) increase in metamorphic/hydrothermal gradients in the gold system (depth), 2) decrease in the refractory properties of the host mineral, and 3) increase in the amount of post-depositional, host-mineral recrystallization and deformation. Gold evolved from primary solid-solution within sulphide/arsenide minerals, to colloidal and micrometre-size particles concentrated in voids, fractures and internal grain boundaries, and finally to microscopic and larger particles at sulphide/arsenide grain margins and in the gangue assemblage. The general conclusions presented here are applicable to As-rich gold deposits of all ages, worldwide. The presence of gold in late fractures is insufficient evidence for late-stage introduction of gold in mesothermal gold systems.

show abstract

mentioning

confidence: 96%

Gold mineralization in As-rich mesothermal gold ores of the Bogosu-Prestea mining district of the Ashanti Gold Belt, Ghana: remobilization of ?invisible? gold

1994

View full text Add to dashboard Cite

show abstract

“…Transmission electron microscopy studies by Bakken et al 8,9 revealed finely disseminated submicrometer gold particles down to less than 100A in pyrite from the Carlin mine. It is reasonable to assume that similar submicroscopic dispersions of gold in pyrite would occur in Gold Quarry sulfidic ore types.…”

Section: Sulfidic Refractory Oresmentioning

confidence: 99%

Processing Gold Quarry refractory ores

Hausen¹

1989

JOM

View full text Add to dashboard Cite

“…High-resolution transmission and Auger electron microscopy examination determined that gold is present in two habits (Hochella et al, 1986;Bakken et al 1989): (1) as discrete particles that vary from 50 to 200 Â in diameter that are encapsulated primarily in pyrite, but also in cinnabar and quartz, and (2) as free gold particles up to 100 Â in diameter that are associated with illite.…”

Section: Occurrence Of Goldmentioning

confidence: 99%

Le lien genetique entre la mineralisation en or et en mercure et l evolution petrolifere

Lu¹

1994

View full text Add to dashboard Cite

The Danzhai gold-mercury deposit is situated in the eastern region of Guizhou province, southwest of P. R. China.The Danzhai deposit is one of the gold-mercury-antimony-barite deposits in the Sandou-Danzhai ore belt, which is controlled by regional fault system Fi. The host rocks are Upper Cambrian and Lower Ordovician carbonates. Wall rock alteration is dominated by silicification and carbonatization. The major mineral assemblages consist of cinnabar, arsenopyrite, stibnite, pyrite and realgar, orpiment as well as barite. Chemical analyses show that gold is positively correlated with arsenic so that the gold may be mainly associated with arsenic minerals. The Au/Ag ratio is always greater than 1 in the gold ore. Hydrocarbons, particularly bitumen, are abundant in both the host rocks and the ore. The geological characteristics of the Danzhai gold-mercury deposit is quite similar to that of Carlin gold deposit in the western U.S.A except the Danzhai deposit is rich in organic matter and not associated with igneous rocks.A number of gold-mercury-antimony-barite deposits are distributed in or around the Majiang-Danzhai oil trap, and all of these deposits are present under the ancient interface between petroleum and oilfield brine (-500 m). Field observation shows that a variety of forms of hydrocarbon occur not only in the host carbonates but in the ore deposit as well. Patch-like bitumen, veinlet bitumen as well as stylolite-like bitumen host sulfide minerals such as arsenopyrite and cinnabar while metal sulfides such as cinnabar and gangue minerals also host bitumen. Besides bitumen, paraffin wax is also found in the deposit. An organic petrography study demonstrates that the bitumen in the minerals from the deposit is identical to the bitumen in the former Majiang-Danzhai oil trap. The bitumen is actually pyrobitumen, with a high reflectance, a mosaic texture, and an anisotropic nature but without fluorescence. The reflectance of bitumen from the deposit is high, varying from 2 to 3.8%, and the temperature calculated from this reflectance ranges from 150 to 210°C, indicating that the petroleum in the Majiang-Danzhai oil trap reached the thermal natural gas stage.

show abstract

High-resolution microscopy of gold in unoxidized ore from the Carlin Mine, Nevada

Cited by 109 publications

References 0 publications

Gold mineralization in As-rich mesothermal gold ores of the Bogosu-Prestea mining district of the Ashanti Gold Belt, Ghana: remobilization of ?invisible? gold

Gold mineralization in As-rich mesothermal gold ores of the Bogosu-Prestea mining district of the Ashanti Gold Belt, Ghana: remobilization of ?invisible? gold

Processing Gold Quarry refractory ores

Le lien genetique entre la mineralisation en or et en mercure et l evolution petrolifere

Contact Info

Product

Resources

About