Relationship between bulk mineralogy and induced polarisation responses in iron oxide-copper-gold and porphyry copper mineralisation, northern Chile

2017 ◽  
Vol 48 (4) ◽  
pp. 353-362 ◽  
Author(s):  
Sebastián Aguilef ◽  
Jaime Araya Vargas ◽  
Gonzalo Yáñez
Keyword(s):  
Iron Oxide ◽  
Porphyry Copper ◽  
Northern Chile ◽  
Induced Polarisation ◽  
Copper Gold

Porphyry Copper Discovery Beneath the Valeriano Lithocap, Chile

SEG Discovery ◽  
2016 ◽  
pp. 1-20
Author(s):  
Richard H. Sillitoe ◽  
Claudio Burgoa ◽  
David R. Hopper
Keyword(s):  
Gold Mineralization ◽  
Porphyry Copper ◽  
Northern Chile ◽  
Porphyry Copper Deposits ◽  
Copper Deposits ◽  
Alteration Zones ◽  
Copper Gold ◽  
Drill Holes

ABSTRACT Exploration for porphyry copper deposits beneath barren or poorly mineralized, advanced argillic lithocaps is becoming common­place; however, there have been few discoveries except in cases where the copper ± gold ± molybdenum mineralization has been partly exposed, typically as a result of partial lithocap erosion. At Valeriano, in the high Andes of northern Chile, completely concealed Miocene porphyry copper-gold mineralization was recently discovered beneath a lithocap. Here, the results of the staged drilling program that led to the discovery are summarized, with emphasis on the key geologic, alteration, and mineralization features that provided guidance. The final deep drill holes of the 16-hole program cut well-defined advanced argillic and sericitic alteration zones before entering chalcopyrite ± bornite–bearing, potassic-altered porphyry, with grades of 0.7 to 1.2% Cu equiv, at depths of ~1,000 to >1,800 m.

The Hypogene Iron Oxide Copper-Gold Mineralization in the Mantoverde District, Northern Chile

2010 ◽  
Vol 105 (7) ◽  
pp. 1271-1299 ◽  
Author(s):  
A. A. Rieger ◽  
R. Marschik ◽  
M. Diaz ◽  
S. Holzl ◽  
M. Chiaradia ◽  
...  
Keyword(s):  
Iron Oxide ◽  
Gold Mineralization ◽  
Northern Chile ◽  
Copper Gold

scholarly journals Silician Magnetite from the Copiapó Nordeste Prospect of Northern Chile and Its Implication for Ore-Forming Conditions of Iron Oxide–Copper–Gold Deposits

Minerals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 529 ◽  
Author(s):  
Elías González ◽  
Shoji Kojima ◽  
Yoshihiko Ichii ◽  
Takayuki Tanaka ◽  
Yoshikazu Fujimoto ◽  
...  
Keyword(s):  
High Temperature ◽  
Iron Oxide ◽  
Gold Deposits ◽  
Northern Chile ◽  
Exchange Reactions ◽  
Iocg Deposits ◽  
X Ray ◽  
Copper Gold ◽  
High Concentrations ◽  
Substantial Factor

Silica-bearing magnetite was recognized in the Copiapó Nordeste prospect as the first documented occurrence in Chilean iron oxide–copper–gold (IOCG) deposits. The SiO2-rich magnetite termed silician magnetite occurs in early calcic to potassic alteration zones as orderly oscillatory layers in polyhedral magnetite and as isolated discrete grains, displaying perceptible optical differences in color and reflectance compared to normal magnetite. Micro-X-ray fluorescence and electron microprobe analyses reveal that silician magnetite has a significant SiO2 content with small amounts of other “impure” components, such as Al2O3, CaO, MgO, TiO2, and MnO. The oscillatory-zoned magnetite is generally enriched in SiO2 (up to 7.5 wt %) compared to the discrete grains. The formation of silician magnetite is explained by the exchange reactions between 2Fe (III) and Si (IV) + Fe (II), with the subordinate reactions between Fe (III) and Al (III) and between 2Fe (II) and Ca (II) + Mg (II). Silician magnetite with high concentrations of SiO2 (3.8–8.9 wt %) was similarly noted in intrusion-related magmatic–hydrothermal deposits including porphyry- and skarn-type deposits. This characteristic suggests that a hydrothermal system of relatively high-temperature and hypersaline fluids could be a substantial factor in the formation of silician magnetite with high SiO2 contents.

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