Geology and hydrothermal alteration at the Maggie porphyry copper-molybdenum deposit, south-central, British Columbia

1976 ◽  
Author(s):  
J L Jambor
Keyword(s):  
British Columbia ◽  
Hydrothermal Alteration ◽  
Porphyry Copper ◽  
South Central ◽  
Molybdenum Deposit

Seismic and potential‐field imaging of the Guichon Creek batholith, British Columbia, Canada, to delineate structures hosting porphyry copper deposits

Geophysics ◽  
2000 ◽  
Vol 65 (5) ◽  
pp. 1418-1434 ◽  
Author(s):  
Baishali Roy ◽  
Ron M. Clowes
Keyword(s):  
British Columbia ◽  
Seismic Reflection ◽  
Porphyry Copper ◽  
Regional Scale ◽  
Low Grade ◽  
Depth Range ◽  
Porphyry Copper Deposits ◽  
Near Surface ◽  
Copper Deposits ◽  
South Central

The Guichon Creek batholith (GCB), located in south‐central British Columbia, contains several large, low‐grade copper deposits of considerable economic importance. The surface geology of the Guichon batholith and its surrounding region have been well mapped; however, little information about subsurface features is available. The batholith consists of four major phases, emplaced radially outward, which can be separated on the basis of their texture and composition. Previous interpretation of gravity data suggests a mushroom‐shaped structure for the batholith. Data from Lithoprobe seismic reflection line 88-11, acquired across the batholith in 1988, reveal weakly coherent east‐dipping reflections on the west side and west‐dipping reflections on the east in the upper 10 km. To determine if these are related to structures associated with the batholith, we reprocessed the upper 6 s with particular emphasis on applications of signal enhancement techniques (e.g., pattern recognition methods, refraction statics, dip moveout corrections) and correlation of the improved subsurface images with the geological environment associated with porphyry copper deposits. Low near‐surface velocities correlate well with the phases of the batholith hosting the major copper deposits, which structurally lie in faulted and brecciated regions. Although the top 1.5 km cannot be imaged by the regional‐scale seismic reflection data, the reprocessed seismic section helps define the edges of the batholith, its various concentric phases, and the stem in the depth range of 1.5 to 10 km. The seismic results are complemented by 2.5-D (profile sense) modeling and 3-D inversion of regional‐scale gravity and high‐resolution aeromagnetic data. These show a low‐density and low‐magnetic‐susceptibility region associated with the batholith that extends to more than 10 km depth. The region of active mining interest lies above a circular low‐susceptibility area at 2 km depth and a low‐velocity region. Integrated interpretation of geophysical results and geological observations indicates the GCB is a funnel‐shaped feature in which mineralization is located above the stem of the batholith.

The Origin of Sheet Fractures in the Galore Creek Copper Deposits, British Columbia

1971 ◽  
Vol 8 (6) ◽  
pp. 704-711 ◽  
Author(s):  
Donald G. Allen
Keyword(s):  
British Columbia ◽  
Hydrothermal Alteration ◽  
Porphyry Copper ◽  
Surface Feature ◽  
Porphyry Copper Deposits ◽  
Volume Increase ◽  
Copper Deposits ◽  
Feature Characteristic

A surface feature characteristic of the Galore Creek copper deposits is a set of well-developed closely-spaced fractures, termed sheet fractures. The formation of these fractures is attributed to the widespread presence of anhydrite, a hydrothermal alteration mineral associated with copper. The fractures apparently developed as a consequence of the volume increase due to hydration of the anhydrite to gypsum by meteoric water.The Galore Creek deposits have many characteristics of porphyry copper deposits, in many of which anhydrite or gypsum has been reported. Anhydrite may be responsible for the development of sheet fractures elsewhere.

scholarly journals RECOGNIZING PORPHYRY COPPER POTENTIAL FROM TILL ZIRCON COMPOSITION: A CASE STUDY FROM THE HIGHLAND VALLEY PORPHYRY DISTRICT, SOUTH-CENTRAL BRITISH COLUMBIA

2021 ◽  
Author(s):  
Robert G. Lee ◽  
Alain Plouffe ◽  
Travis Ferbey ◽  
Craig J.R. Hart ◽  
Pete Hollings ◽  
...  
Keyword(s):  
British Columbia ◽  
Trace Element ◽  
Detrital Zircon ◽  
Porphyry Copper ◽  
Detrital Zircons ◽  
Late Triassic ◽  
Ionization Mass ◽  
South Central ◽  
Copper Mineralization ◽  
Porphyry Copper Mineralization

Abstract The detrital zircons in tills overlying the Guichon Creek batholith, British Columbia, Canada, have trace element concentrations and ages similar to those of zircons from the bedrock samples from which they are interpreted to have been sourced. Rocks from the core of the batholith that host porphyry copper mineralization have distinct zircon compositions relative to the distal, barren margin. We analyzed 296 zircons separated from 12 subglacial till samples to obtain U-Pb ages and trace element compositions. Laser ablation U-Pb ages of the detrital zircons overlap within error with chemical abrasion-thermal ionization mass spectrometry U-Pb ages of the Late Triassic Guichon Creek batholith and confirm that the detrital zircons are likely derived from the batholith. The youngest intrusions of the batholith produced the Highland Valley Copper porphyry deposits and contain distinctive zircons with elevated Eu/EuN* >0.4 attributed to high magmatic water contents and oxidation states, indicating higher porphyry copper potential. Zircon from till samples adjacent to and 9 km down-ice from the mineralized centers have mean Eu/EuN* >0.4, which are indicative of potential porphyry copper mineralization. Detrital zircon grains from more distal up- and down-ice locations (10–15 km) have zircon Eu/EuN* mean values of 0.26 to 0.37, reflecting background values. We conclude that detrital zircon compositions in glacial sediments transported several kilometers can be used to establish the regional potential for porphyry copper mineralization.

Hydrothermal Alteration and Fluid Chemistry of the Endako Porphyry Molybdenum Deposit, British Columbia

2000 ◽  
Vol 95 (1) ◽  
pp. 183-202 ◽  
Author(s):  
D. Selby ◽  
B. E. Nesbitt ◽  
K. Muehlenbachs ◽  
W. Prochaska
Keyword(s):  
British Columbia ◽  
Hydrothermal Alteration ◽  
Fluid Chemistry ◽  
Molybdenum Deposit

A thermodynamic approach to the understanding of the supergene alteration at the Afton copper mine, south-central British Columbia

1982 ◽  
Vol 19 (12) ◽  
pp. 2378-2386 ◽  
Author(s):  
Y. T. J. Kwong ◽  
T. H. Brown ◽  
H. J. Greenwood
Keyword(s):  
British Columbia ◽  
Extreme Values ◽  
Porphyry Copper ◽  
Copper Oxides ◽  
Thermodynamic Approach ◽  
Porphyry Copper Deposits ◽  
Native Copper ◽  
Copper Mine ◽  
Supergene Zone ◽  
South Central

A thermodynamic reconstruction of the supergene alteration at the Afton copper mine, south-central British Columbia, demonstrates that the dominance of native copper and the lack of copper enrichment in the supergene zone are related to the relatively mafic composition of the wall rocks and the absence of abundant hypogene sulfides. Supergene alteration of porphyry copper deposits in general can be interpreted in terms of a [Formula: see text] plot. Two arbitary "limiting" curves characterized by extreme values of acidic and basic pH can be drawn. A reacting fluid evolving near the acidic limiting curve will produce a well developed leached cap with an enriched supergene ore blanket underneath. In contrast, a reacting fluid evolving near the basic limiting curve will lead to a spectrum of copper oxides and native copper with little enrichment, as typified by Afton.

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