The East Sullivan Stock and its Gold-Copper Potential, Val d’Or, Quebec, Canada

Abstract The East Sullivan Stock (ESS) is a small, composite felsic alkaline pluton of presumed late Archean age in the Val d’Or mining district. Three main facies have been distinguished: monzonite
sensu stricto, porphyritic monzonite, and green trachytic porphyry. This monzonitic group of
rocks is of relatively homogeneous composition with high abundances of Na2O, K2O, Ba, Sr, Rb, Zr,
Mo and LREE. The alkaline ESS is distinguished from other igneous units in the Val d’Or mining
district, such as the Bourlamaque Batholith, by relatively high concentrations of Ba, Sr, Rb, Mo, Cu and Au. The ESS hosts many base (Cu, Mo) and precious (Au) metal occurrences, including: (1)
porphyry style Cu-Au-Mo disseminated sulfide deposits, (2) Cu-Au deposits in volcanic rocks near
the ESS contact, and (3) pyritic gold mineralization in east-west trending shear zones. The ESS is well defined by concentrical zoning on the aeromagnetic vertical gradient color map, and displays four linear trends, which are assumed to be structural lineaments, at 035°-055°, 320°-300°, eastwest, and north-south. The main mineral occurrences related to the stock display a preferred spatial association with the east-west linear magnetic trends.
The ESS is preferentially located along a major structure and was emplaced late in the evolution
of the Abitibi subprovince like other felsic alkaline plutons. This stock is similar to late-tectonic mineralized felsic alkaline intrusions of the Kirkland Lake and Larder Lake mining districts in Ontario, and to the Allard stock in the U.S.A. which is associated with gold and base metal mineralization. Similarities also exist with younger alkaline plutons associated with Cu-Mo-Au porphyry deposits in the Canadian Cordillera, which formed in tensional tectonic environments. The felsic alkaline magma may have formed by partial melting of deeply buried supracrustal rocks, concomitant with the development of deep fractures such as the Cadillac Fault. In such an environment, hydrothermal solutions carrying remobilized metals from deep supracrustal rocks may have deposited gold and base metals in structural traps. Plutons similar to the ESS should be good targets for mineral exploration.
Keywords: East Sullivan Stock, Gold-Copper, exploration, Hydrothermal solution
Full Access to Technical Paper
PDF version for $20.00
Search
Sort By:  Relevance
Showing results 1 - 4
Text
Summary: The Geological Society has its own quarterly journal called Exploration
and Mining Geology, for the publication of Canadian and international papers on
applied aspects of mineral exploration and exploitation, including mineral
deposit geology, geochemistry, and geophysics, mining geology, mineral resource
appraisal and estimation methods, environmental geology, and case histories. The
editor of the journal is Jeremy P. Richards
Publication: Exploration & Mining Geology
Issue: 1
Volume: 5
Year: 1996
Text
Summary: The Na-feldspar orebodies in Sardinia occur along structures belonging to a regional ENE-WSW system that developed during the late stages of the Hercynian orogeny, and that was reactived during the Alpine orogeny. The main petrographic facies include granitoids, albitized granitoids, albitites (more or less rich in quartz), and albitites containing Mg minerals. Field observations and petrological and geochemical data point toward a metasomatic origin for the albitite orebodies.
Albitization...
Publication: Exploration & Mining Geology
Author(s): R. BORNIOLI, S. FADDA, M. FIORI, S.M. GRILLO
Keywords: Albite deposits, Mineralogical evidence, Geochemical evidence, Na-feldspar orebodies, albitizing fluids
Issue: 1
Volume: 5
Year: 1996
Text
Summary: Oxide-facies banded iron formation in the Third Portage Lake area is hosted by ultrama?c and calc-alkaline volcanic rocks and related sedimentary rocks of the Archean (2.8 Ga) Woodburn Lake Group, 80 km north of Baker Lake. These rocks record at least two phases of metamorphism/metasomatism. Greenschist facies metamorphism, in the temperature range of 370°C to 520°C and at pressures above 2.3 kbar, has affected all rocks on a regional scale. Later mineralization and alteration of banded iron...
Publication: Exploration & Mining Geology
Author(s): A.E. ARMITAGE, R.S. JAMES
Keywords: Mineralization, Gold mineralization, Northwest Territories, Portage Lake, Metamorphism.
Issue: 1
Volume: 5
Year: 1996
Text
Summary: The Ni-rich Epidote Zone of the Fraser Mine at Sudbury is characterized by alteration assemblages rich in epidote, actinolite and magnetite which are roughly concentrically zoned and up to hundreds of meters in length. These zones form discrete areas within the igneous Footwall Breccia below the Sudbury Igneous Complex. The assemblages grade from epidotized Footwall Breccia matrix, through actinolite-bearing rocks with few vestiges of original Footwall Breccia textures, into the most...
Publication: Exploration & Mining Geology
Author(s): CATHARINE E.G. FARROW
Keywords: Geochemistry, Geochemical evolution, Frasier Mine.
Issue: 1
Volume: 5
Year: 1996
Powered by Coveo Enterprise Search