Geochronological constraints on the development of the Cross Lake greenstone belt, northwest Superior Province, Manitoba

Corkery, M. Timothy; Davis, Donald W.; Lenton, Paul G.

doi:10.1139/e92-172

Cited by 29 publications

(8 citation statements)

References 23 publications

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“…In addition to monazite ages, Algoman granites (ca. 2650 Ma; Heather et al 1996) and granitic pegmatites (2640 Ma; Corkery et al 1992) are widespread, and high-grade metamorphism accompanied by deformation is evident in deep-crust settings, including Kapuskasing and Pikwitonei (Heaman et al 1986). These events are synchronous at the scale of the Superior Province (2000 ϫ 1600 km), implying a process not linked to a margin.…”

Section: Late Metamorphic Events In Superior Provincementioning

confidence: 99%

Tectonothermal Evolution of the Northern Minto Block, Superior Province, Quebec, Canada

Percival

Skulski

2000

The Canadian Mineralogist

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Previously considered one of Earth's largest granulite terranes, the Minto block, in northern Quebec, consists dominantly of granitic rocks with sparse supracrustal remnants that record low-pressure, high-temperature metamorphism to the amphibolite and granulite facies at ca. 2.7 Ga. Much of the region is underlain by plutonic rocks, including igneous charnockitic bodies, that provide little evidence of metamorphism. In contrast, pelitic assemblages in low-grade greenstone belts and their higher-grade shoulders define four metamorphic zones: 1) sub-staurolite-grade slates, found only in the Duquet belt, 2) staurolite -andalusite -sillimanite -garnet-zone schists, present in all belts, 3) marginal garnet -sillimanite ± kyanite migmatites, and 4) garnetsillimanite ± cordierite and garnet -orthopyroxene granulites, as enclaves within plutonic units. A prograde low-pressure, hightemperature regional facies-series is defined by andalusite -sillimanite assemblages, thermobarometric analyses that indicate peak conditions ranging from 3 kbar, 560°C to 8.4 kbar, 840°C, and short segments of anticlockwise P-T trajectories preserved in two of the lowest-grade areas. Kyanite occurs in migmatites in the vicinity of a ca. 2.81 Ga shear zone bounding two distinct supracrustal assemblages and marks an earlier Barrovian event. All belts are polydeformed, with a common, broadly synmetamorphic, NNW-striking, steep foliation and down-dip lineation related to regional-scale F 2 folds. Distributed late-metamorphic dip-slip shear appears responsible in some areas for cross-strike juxtaposition of low-and high-grade metamorphic zones. Older, generally poorly preserved D 1 deformation, recognized in several belts, may represent accretionary structures. Variably developed younger deformation includes NNW dextral transcurrent brittle-ductile shear zones (S 3 ), variably developed east-trending F 4 folds, and WNW-striking pseudotachylite zones. U-Pb monazite ages of 2702 Ma date high-grade metamorphism of a pelitic granulite, crystallization of two diatexites, and staurolite-zone metamorphism in one schist. Together with similar zircon ages of crust-derived granites, these data point to a major collisional orogeny at this time. Older titanite (2748-2765 Ma) indicates areas that escaped >650°C metamorphism during the 2.7 Ga event. Younger monazite occurs in a migmatite-grade rock (2688, 2672 Ma) and staurolite-zone schists (2679( -2642( , 2648( , 2637( , and 2642( -2628, similar to titanite ages in greenstones (2643-2550 Ma) and 40 Ar/ 39 Ar hornblende ages (2.64-2.56 Ga). These post-peak metamorphic ages in the greenstone belts based on monazite and titanite are attributed to hydrothermal growth from fluids channeled along permeable zones; they may reflect late reheating events observed throughout the Superior Province as leucogranitic magmatism, metamorphism in the deep crust, and mineral growth in shear zones. SOMMAIRELe socle de Minto, dans le nord du Québec, considéré antérieurement comme un des plus vastes terrains de roches transformé...

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Section: Late Metamorphic Events In Superior Provincementioning

confidence: 99%

Tectonothermal Evolution of the Northern Minto Block, Superior Province, Quebec, Canada

Percival

Skulski

2000

The Canadian Mineralogist

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“…15. Synthesis of U-Pb ages for syn-to late-orogenic events in the northwestern Superior province displayed roughly along a northwest-southeast profile (based on data from Andrews et al, 1986;Heaman et al, 1986;Turek et al, 1986;Mezger et al, 1989;Corkery et al, 1992;Corfu and Stone, 1998a, b;and this study).…”

Section: Significance Of the U-pb Agesmentioning

confidence: 86%

“…Various episodes of metamorphism and migmatization have been documented for the interval of 2700 to 2600 Ma in the Pikwitonei high-grade domain to the northwest of Island Lake (Heaman et al, 1986;Mezger et al, 1989;Figs. 1A and 15), and peraluminous granite associated with pegmatites has been dated at ≤2653 Ma in the Cross Lake greenstone belt (Corkery et al, 1992). Interestingly, the area immediately surrounding Red Lake (Fig.…”

Section: Significance Of the U-pb Agesmentioning

confidence: 97%

Structural Setting and Geochronology of Auriferous Quartz Veins at the High Rock Island Gold Deposit, Northwestern Superior Province, Manitoba, Canada

Lin¹

2002

Economic Geology

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The High Rock Island gold deposit occurs across the intrusive contact between a granitoid pluton and a mafic metavolcanic rock at the southern margin of the Island Lake greenstone belt. The main structure at the deposit is a ~5-m-wide, north-trending, and steeply dipping dextral ductile-brittle fault zone (the "main fault") that cuts at a right angle across the pluton-greenstone contact and the contact-parallel foliation. Total horizontal displacement along the fault is ~9 m, of which ~3 m is accomplished by ductile shearing and ~6 m by brittle faulting.The gold deposit consists of steeply dipping auriferous quartz veins that are hosted in, and were emplaced during, the dextral shearing along the main fault. They include: (1) the "main vein" (a fault-fill vein) that occurs in the center of, and is parallel to, the main fault, (2) en echelon veins (extensional veins) that occur on both sides of the main vein and cut across the foliation, and (3) foliation-parallel veins that occur locally. Detailed analysis of the geometry of the en echelon veins, partly based on a new Mohr circle construction method, shows that the deformation in the main fault was transtensional. The faulting and quartz vein emplacement were controlled by the contacts of a north-trending mafic dike. They took place under greenschist facies conditions, postdating amphibolite facies metamorphism in the host rock.The mineralized quartz veins contain both monazite and titanite, which yield U-Pb ages of 2687 ± 2 Ma and 2658 ± 5 Ma, respectively. Although the exact interpretation of the two ages remains somewhat uncertain, it is likely that gold could have been introduced during a secondary event at ~2658 Ma in a vein originally formed at ~2687 Ma or earlier. This is supported by the isotopic affinity of Pb in titanite with that in galena that is spatially closely associated with gold. The interpretation that gold was introduced after the emplacement of the quartz veins is also consistent with the observation that the main vein only contains significant gold (and sulfide) where it is cut by a vein-parallel fault. In any case, the mineralization at the deposit took place at the latest stages of orogenic development in the northwestern Superior province.

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“…Normalization values are from Hofmann (1988). Trueman et al (1971) Pipestone Lake Manitoba Low to medium Medium Corkery et al (1992) Bad Vermilion Lake Ontario Low Low to medium Ashwal et al (1983Ashwal et al ( , 1985 Shawmere Ontario High Low to medium Riccio (1981) Doré Lake Quebec Low to medium Low to medium Mortensen (1993) Big Trout Lake Ontario Medium Medium Thurston et al (1980) Bell River Bell River Low to medium Low to medium Ashwal et al (1993) Nelson…”

Section: Discussionmentioning

confidence: 99%

Formation of the Neoarchean Bad Vermilion Lake Anorthosite Complex and spatially associated granitic rocks at a convergent plate margin, Superior Province, Western Ontario, Canada

et al. 2016

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The Bad Vermilion Lake Anorthosite Complex (henceforth, the BVLA Complex) in western Ontario is one of the well-exposed, anorthosite-bearing, Archean layered intrusions in the Superior Province, Canada. This study presents new whole-rock major and trace element data for the various units of the Complex, oxygen isotope data for the anorthosite, and major and trace element data for the spatially associated granitic rocks intruding the BVLA Complex to constrain their petrogenetic and geodynamic origin. Zircons from granitic rocks have yielded a 207 Pb/ 206 Pb age of 2716 ± 18 Ma, constraining the minimum intrusion age of the Complex. Despite deformation and greenschist facies metamorphism, primary igneous textures are locally well preserved in the BVLA Complex. Its whole-rock major and trace elemental compositions and the oxygen isotopic systematics appear not to have been substantially modified by deformation and metamorphism. Mantle-like oxygen isotope signatures and major and trace element compositions are inconsistent with significant crustal contamination of the BVLA Complex during its emplacement. The existence of primary calcic igneous plagioclase, coherent negative Nb anomalies (Nb/Nb*=0.08-0.88), and geochemical similarities between gabbros from the BVLA Complex and gabbros from Cenozoic arcs collectively suggest an intra-oceanic subduction zone geodynamic setting for the Complex. Near-flat REE patterns in the various units of the BVLA Complex suggest that they were derived from melting of a shallow source beneath a subarc mantle wedge. Trends in immobile major (e.g., MgO) and trace (e.g., Zr) element data indicate that the mineralogical composition of the Complex can be explained by fractional crystallization and accumulation of olivine, orthopyroxene, clinopyroxene, plagioclase and 3 possibly amphibole. Compositionally, the bordering granitic rocks are A 2-type and strongly enriched in Th and REE (>100 times chondrite) and depleted of Ba, Sr, Eu and Ti. We suggest that they formed in a post-collisional, extensional, tectonic regime following emplacement of the BVLA Complex in an oceanic arc.

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Geochronological constraints on the development of the Cross Lake greenstone belt, northwest Superior Province, Manitoba

Cited by 29 publications

References 23 publications

Tectonothermal Evolution of the Northern Minto Block, Superior Province, Quebec, Canada

Tectonothermal Evolution of the Northern Minto Block, Superior Province, Quebec, Canada

Structural Setting and Geochronology of Auriferous Quartz Veins at the High Rock Island Gold Deposit, Northwestern Superior Province, Manitoba, Canada

Formation of the Neoarchean Bad Vermilion Lake Anorthosite Complex and spatially associated granitic rocks at a convergent plate margin, Superior Province, Western Ontario, Canada

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