A holistic model for the origin of orogenic gold …
These include the presence of hypozonal deposits in amphibolite-facies domains, their anomalous multiple sulfur isotopic compositions, and problems of derivation of gold-related elements from …
Amphibolite Classification, Composition, …
Amphibolite. Amphibolite is a coarse-grained metamorphic rock, predominantly composed of mineral amphibole and plagioclase feldspar.It can also contain minor amounts of other metamorphic …
Gold deposits in amphibolite and granulite facies terranes …
Among those, the La Pointe deposit has several characteristics similar to other amphibolite facies orogenic gold deposits, such as disseminated and replacement mineralization, and an alteration ...
Marymia: an Archean, amphibolite facies-hosted, orogenic lode-gold
Abstract.The Marymia gold deposit, comprising two orebodies, Keillor 1 and Keillor 2, is at the northern end of the Plutonic Well greenstone belt in the Marymia Inlier, in the southern Capricorn Orogen, just north of the Yilgarn craton. The Marymia Inlier is a discrete fault-bounded Archean gneiss–granitoid–greenstone domain surrounded by …
Gold placers of the historical Fortymile River region, Alaska
The close spatial association of creeks containing placer gold and the gneiss, schist, amphibolite, and marble unit strongly suggests this metamorphic unit is the gold source. High terrace gravels record a time from the late Tertiary to early Pleistocene when the ancestral Fortymile River and its major tributaries, the North and South Forks ...
Unravelling the upper-amphibolite facies Glenburgh …
KEYWORDS: amphibolite facies, geochronology, gold, metamorphism, migmatite Introduction 'Orogenic' gold deposits commonly form in greenschist facies terrains, and are rare in high-grade metamorphic rocks (Groves, 1993). This is conventionally attributed to gold mineralization forming from gold complexes
Live Gold & Silver Spot Price Charts | APMEX®
Read below for information on how investors use our spot price charts to follow the Precious Metals market movements and determine their investment strategies. Take advantage of the live spot prices by shopping our Top Sellers categories for Gold, Silver, Platinum and Palladium today. Gold. $2,379.00 USD. $8.30 USD +0.35%. View Details. Silver.
Expanding the metamorphic devolatilization model: …
Gold deposits are rare in upper-amphibolite to granulite facies environments. Known examples commonly attract debate about whether they formed under these conditions or instead represent ...
Formation of gold deposits: Review and evaluation …
The most obvious shortcoming is in considering ore deposits found in rocks of uppermost amphibolite and granulite facies domains where temperatures were …
Amphibolite Classification, Composition, Formation …
Amphibolite is a coarse-grained metamorphic rock, predominantly composed of mineral amphibole and plagioclase …
Hydrothermal transport and depositional processes in Archean lode-gold
Several studies have addressed the likely concentrations and mode of transport of gold in sub-amphibolite-facies lode-gold ore-fluids using the then available thermodynamic data and ore-fluid conditions based on fluid inclusion and mineral stability constraints (e.g. Phillips and Groves, 1983; Mikucki and Groves, 1990b).
Expanding the metamorphic devolatilization model: …
Our thermodynamic simulations indicate that subsolidus metamorphic devolatilization of komatiites at ~700 °C (upper amphibolite facies) can unlock …
Amphibolite | Metamorphic, Igneous, Foliated
Amphibolite, a rock composed largely or dominantly of minerals of the amphibole group. The term has been applied to rocks of either igneous or metamorphic origin. In igneous …
Roles and perspectives of A- and I-type magmas in rare …
These characteristics suggest that the diversity of REE and gold mineralization was the result of interaction between the lithospheric mantle and hybrid sediment-derived melts and aqueous fluids under rutile-bearing eclogite-facies (>2.0 GPa) conditions within the Luxi terrane and with aqueous fluids under amphibolite- to eclogite …
(PDF) Metasomatized mantle sources for orogenic gold
Many workers accept a metamorphic model for orogenic gold ore formation, where a gold-bearing aqueous-carbonic fluid is an inherent product of devolatilization across the greenschist-amphibolite ...
Nature and Origin of the Amphibolites in the …
It is suggested that a gold-bearing magmatic rock was metamorphosed into amphibolite and metadolerite with the subsequent partitioning of Fe-oxide, rutile and Fe-rich biotite in the gold grains ...
(PDF) Controls of gold-quartz vein formation during regional …
The Navachab gold mine in central Namibia is situated in amphibolite-facies, marble-dominated metasediments of the Neoproterozoic Damara Sequence in the Pan-African Damara Belt.
Texture and Trace Element Composition of Rutile in Orogenic Gold
Actinolite is common in the low amphibolite facies country rocks of the Roberto deposit (Fontaine et al., 2015; Table 2), and andradite is commonly associated with the gold mineralization at Big Bell, which is hosted in middle amphibolite facies country rocks (Mueller et al., 1996; Table 2). Calcium is a major element in tremolite, actinolite ...
Golden Amphibolite. – GemstoneGeeks Pty. Ltd.
The amphibolite, most likely grunerite, has now been largely altered to hematite, goethite and quartz and it displays a beautiful golden iridescence. Also called "Gold Leaf Stone". It occurs in the Pilbara region of Western Australia on Abydos Station approximately 120 km south of Port Hedland.
Amphibolite
Senja, Norway. Width of sample 10 cm. Amphibolite is a metamorphosed mafic igneous rock ( basalt, gabbro) although it is usually difficult to determine the protolith because original features are often obliterated. …
Formation of gold deposits: a metamorphic devolatilization model
A metamorphic devolatilization model can explain the enrichment, segregation, timing, distribution and character of many goldfields such as those found in Archean greenstone belts, slate‐belts and other gold‐only provinces. In this genetic model, hydrated and carbonated greenschist facies rocks, particularly metabasic rocks, are …
The Hemlo Gold Deposit, Ontario: An Example of Melting
The Marco zone is hosted by amphibolite-grade, strongly foliated volcanic rocks and consists of disseminated gold, with an apparent thickness ranging from 1.8 to 39.5 m and gold grades up to 23 g ...
The Coolgardie Goldfied, Western Australia: district-scale
Archaean lode gold deposits in the Coolgardie Goldfield, Western Australia, occur in mafic and ultramafic rocks which have been metamorphosed to the amphibolite facies. Mineralisation was broadly synchronous with peak metamorphism, the main phase of granitoid emplacement, and regional deformation. Several different structural styles are …
Age, petrogenesis, and tectonic setting of granitic gneiss and
The Weizigou gold deposit is located 30 km northwest of Jixi in Heilongjiang Province. Strata exposed in the orefield are mainly the Ximashan Formation, which is composed of biotite-amphibole granulite with marble and migmatite intercalations; the Jiantang Formation, which comprises marble, quartz schist, migmatite, granulite, and …
Amphibolite
A garnet amphibolite from the Imjingang belt in the Korean Peninsula is chosen as an example of the P-T-t estimation for metamorphic rocks with an upper amphibolite facies peak ... uranium, IOCG, porphyry, stratiform tungsten, epithermal, and gold deposits, both intrusion-related and orogenic, have also been documented (Figure 1 and Table 1 ...
Amphibolite
History. Amphibolite--sometimes also referred to as hornblende--is a metamorphic rock that contains amphibole minerals (hence its name) and feldspars. This dark and heavy rock comes in both banded and crystal forms and can contain a range of other gemstones and materials. In antiquity, amphibolite was carved into sculpture.
Fate of gold and base metals during metamorphic …
Metamorphic devolatilization of pelite is a key process in sourcing fluids and metals for orogenic gold deposits. The process of extracting S, Au, As, Cu, Pb and Zn …
The Jurassic Danba hypozonal orogenic gold deposit, …
The genesis of hypozonal orogenic gold deposits is highly controversial, with both crustal metamorphic fluids and variously derived sub-crustal fluids suggested as fluid and metal sources. The Lower Jurassic Danba gold deposit, a rare Phanerozoic hypozonal orogenic gold deposit on the western margin of the Yangtze Craton, China, provides an …
Formation of gold deposits: Review and evaluation of the …
A syn-peak metamorphic introduction of gold (i.e. continuum) in a hydrothermal fluid would lead to in situ partial melting, rather than aqueous gold transport, given the inferred metamorphic grade (see 3 Principles of partial melting in the uppermost amphibolite and granulite facies, 4.2.1 Geological setting of the Big Bell gold deposit). …
Amphibolite: Mineral information, data and localities.
Amphibolite is a gneissose or granofelsic metamorphic rock mainly consisting of green, brown or black amphibole and plagioclase (including albite), which combined form ≥75% of the rock and both of which are present as major constituents; the amphibole constitutes ≥50% of the total mafic constituents and is present in an amount of ≥30%. A …