Giant versus small porphyry copper deposits of Cenozoic age in northern Chile: adakitic versus normal calc-alkaline magmatism

2001 ◽  
Vol 36 (8) ◽  
pp. 794-798 ◽  
Author(s):  
Roberto Oyarzun ◽  
Alvaro Márquez ◽  
Javier Lillo ◽  
Ivan López ◽  
Sergio Rivera
Keyword(s):  
Porphyry Copper ◽  
Alkaline Magmatism ◽  
Northern Chile ◽  
Porphyry Copper Deposits ◽  
Calc Alkaline ◽  
Copper Deposits

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.

scholarly journals Tectonic setting of Cretaceous porphyry copper deposits of northern Chile (28°-30° S) and its relations with magmatic evolution and metallogeny

2020 ◽  
Vol 47 (3) ◽  
pp. 469
Author(s):  
Christian Creixell ◽  
Javier Fuentes ◽  
Hessel Bierma ◽  
Esteban Salazar
Keyword(s):  
Early Cretaceous ◽  
Late Cretaceous ◽  
Porphyry Copper ◽  
Northern Chile ◽  
Porphyry Copper Deposits ◽  
The West ◽  
Copper Deposits ◽  
Magmatic Arc ◽  
Fault Systems ◽  
Back Arc

Cretaceous porphyry copper deposits of northern Chile (28º-29º30’ S) are genetically related with dacitic to dioritic porphyries and they represent a still poorly-explored target for Cu resources. The porphyries correspond to stocks distributed into two separated discontinuous NS trending belts of different age. The location of these porphyries is generally adjacent to orogen-parallel major fault systems that extend along the studied segment and also have a marked temporal relationship with deformation events registered along these structures. A first episode of Cu-bearing porphyry emplacement took place between 116 and 104 Ma (Mina Unión or Frontera, Cachiyuyo, Punta Colorada, Dos Amigos, Tricolor porphyries). These Early Cretaceous dacite to diorite porphyries are spatially associated with the eastern segments of the Atacama Fault System, which records sinistral transpression that started at 121 Ma producing ground uplift, consequent denudation and exhumation of the Early Cretaceous magmatic arc. This resulted in a change from marine to continental deposition with an angular unconformity in the site of the back-arc basin after of eastward migration of the deformation around 112-110 Ma. At the scale of the continental margin, this deformation is correlated with early stage of the Mochica Orogenic event described in Perú. A second episode of Cu-bearing porphyry emplacement occurred between 92 and 87 Ma (Elisa, Johana, Las Campanas and La Verde deposits), which are spatially and temporally associated with the regional-scale Las Cañas-El Torito reverse fault, active between 89 and 84 Ma, during the Peruvian Orogenic Phase. This fault up thrust to the west part of the Chañarcillo Group rocks (Lower Cretaceous) over the younger upper levels of the Cerrillos Formation (Upper Cretaceous). The integrated geological mapping and geochemical data of the Early to Late Cretaceous volcanic rocks indicates that both Early Cretaceous sinistral transpression and Late Cretaceous east-west compression were not significant in promote changes in magma genesis, except for slight changes in trace element ratios (increase in Th/Ta, Nb/Ta and La/Yb) suggesting that the Late Cretaceous deformation event produced only slightly increase in crustal thickness (>40 km), but far from being comparable to major Cenozoic orogenic phases, at least along the magmatic arc to back-arc domains in the study area. Finally, our study give insights about regional geological parameters that can be used as a first order guide for exploration of Cu resources along Cretaceous magmatic belts of northern Chile, where both Early and Late Cretaceous Cu-bearing porphyry intrusions are restricted to a large structural block bounded to the west and east by Cretaceous fault systems.

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