Oxygen isotope evidence for the origin of discrete granitoid plutons from the Archean western Wabigoon Belt, northwestern Ontario

doi:10.1016/0301-9268(81)90033-4

Precambrian Research

Volume 14, Issue 1, January 1981, Pages 21-30

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Abstract

The whole-rock δ ¹⁸O values of samples from twelve discrete Archean plutons intruding the western Wabigoon granite-greenstone belt, northwestern Ontario, range from 6.8 to 9.5‰. Most samples with δ $^{18} O > 8.7‰$ , however, come from portions of the Burditt Lake stock, or the Esox Lake area, that have been affected by deuteric or metasomatic activity. The distribution of δ ¹⁸O values for the remaining samples is very similar to that known for the large batholithic complexes and gneissic terrains that dominate this portion of northwestern Ontario. The generally low δ ¹⁸O values of the discrete granitoid plutons suggest that ¹⁸O-rich supracrustal rocks were unimportant in their genesis. Like the granitoids of the batholithic complexes and gneissic terrains, the discrete granitoid plutons represent new additions to the Archean sialic crust.

References (20)

L.D. Ayres
Geology of the Trout Lakes area
Ontario Div. Mines, Geol. Rep.
(1974)
D.W. Beaty et al.
Oxygen isotope geochemistry of the Abitibi greenstone belt, Ontario: evidence for seawater/rock interaction and implications regarding the isotopic composition and evolution of the ocean and oceanic crust
Geol. Soc. Am., Abstr. with Prog.
(1979)
D. Birk
The Nature and Timing of Granitoid Plutonism in the Wabigoon Volcanic-Plutonic Belt, Northwestern Ontario
D. Birk
Rb/Sr chronology of the Rainy Lake Archean granitoid batholith, Wabigoon Belt, northwestern Ontario
Can. J. Earth Sci.
(1979)
D. Birk et al.
Rb/Sr isochrons for Archean granitoid plutons within the Wabigoon greenstone belt, northwestern Ontario: a preliminary evaluation
Geol. Surv. Can., Rep. Activities, Pap. 77-1A
(1977)
D. Birk et al.
Rare earth distribution in Archean granitoid plutons of the Wabigoon volcanic-plutonic belt, northwestern Ontario
Can. J. Earth Sci.
(1979)
R.M. Clayton et al.
The use of bromine pentafluoride in the extraction of oxygen from oxides and silicates for isotopic analysis
Geochim. Cosmochim. Acta
(1963)
H. Craig
Standard for reporting concentrations of deuterium and oxygen-18 in natural waters
Science
(1961)
C.F. Gower et al.
Implications of Rb/Sr radiometric data to the evolution of Archean high grade terrain in the Kenora area, English River Subprovince
Geol. Assoc. Can., Abstr. Progr.
(1978)
F.J. Longstaffe
Oxygen Isotope and Elemental Geochemistry of Archean Silicate Rocks from Northern Ontario

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Cited by (6)

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Emplacement of the ca. 2735–2720 Ma Sturgeon plutonic suite (SPS) into 2774–2745 Ma oceanic arc crust of the Savant-Sturgeon Lake greenstone belt, western Superior Province, occurred contemporaneously with South Sturgeon caldera complex formation and deposition of its contained volcanogenic massive sulfide (VMS) deposits and subeconomic Cu–Mo porphyry system. The SPS, which includes both large (∼1400 km²) mid-crustal intrusions and smaller, shallower-level mafic and felsic plutons, is interpreted as a series of stratiform-coeval intrusions that represent the magmatic roots and feeder system to a continental margin arc-rift sequence. New Nd and O isotopic results, plus unpublished VMS Pb and published granitoid zircon Hf data, suggest derivation of felsic SPS phases from juvenile (<2.9 Ga) crustal materials and mantle-derivation of mafic SPS phases. Felsic SPS phases include: (a) a high-Al, HREE-depleted tonalite–trondhjemite–granodiorite (TTG) subsuite and (b) a low-Al, HREE-enriched tonalite subsuite. Initially arc rifting resulted in mantle-decompression-melting and crustal under- and intra-plating with mafic magmas, inducing sequential dehydration partial melting of amphibolitic lower to middle crustal protoliths. High-Al SPS TTG-type phases were derived at >30 km depth under garnet-stable P–T conditions, whereas low-Al SPS felsic phases were likely derived at 10–18 km depth, leaving residual amphibole and plagioclase. SPS dioritic phases represent basaltic magma fractionation products. Coeval lower to upper crustal emplacement and eruption of SPS magmas formed a crustal-scale magmatic pumping system that generated and sustained a long-lived (∼15 Ma) thermal corridor. This rift-related thermal corridor was intimately related in time and space, first to: (a) hot and dry, low-Al intrusive and eruptive units, characterized by FII rhyolite chemistry, that initiated and supported a VMS-generating seafloor hydrothermal seafloor system at ca. 2735 Ma; and subsequently to (b) subvolcanic devolatilization of more volatile and K-rich high-Al intrusions that produced porphyry-type mineralization 14 Ma later.
Mantle heterogeneity and crustal recycling in Archean granite-greenstone belts: Evidence from Nd isotopes and trace elements in the Rainy Lake area, Superior Province, Ontario, Canada
1986, Geochimica et Cosmochimica Acta
The ≧2685–2752 Ma old granite-greenstone crust in the Rainy Lake area, Ontario, consists of metaigneous and metasedimentary rocks that range in composition from tholeiite to monzogranite and include anorthosite, trachyandesite, monzodiorite and high-silica rhyodacite. Major element, rare earth and other trace element data are the basis for modelling the formation of the crust by melting of large-ionlithophile element enriched and unenriched mantle, by melting of basalt at mantle to crustal levels and by melting of monzodiorite and tonalite at crustal levels.
All metaigneous rocks lie on a ¹⁴³Nd/¹⁴⁴Nd vs. ¹⁴⁷Sm/¹⁴⁴Nd isochron with an age of 2737 ±42Ma and an initial ¹⁴³Nd/¹⁴⁴Nd of 0.509178 ±33 (ε_Nd = +1.9). This age is consistent with U-Pb zircon ages, which suggests the Nd isotopic system has been unaffected since the crust-forming events. The positive initial ε_Nd's are further evidence for time-averaged depletion in Sm/Nd relative to CHUR for the Archean mantle. The similarity of the initial Nd isotopic composition for both mantle-derived and crustally-derived rocks suggests rapid recycling of crustal components, which were previously derived from depleted mantle sources.
Initial ¹⁴³Nd/¹⁴⁴Nd ratios on individual rocks range from ε_Nd = +3.3 to ε_Nd = −0.4. Younger granitoids have lower ε_Nd values (+1.5 to −0.1) relative to tholeiites and monzodiorites crystallized from mantle-derived melts (+3.3 to +1.0). Thus, incorporation of slightly older crust (ca. 100–200 Ma) in some of the granitoid source areas is possible. Mantle-derived rocks form an isochron of 2764 ±58Ma that represents a minimum age for enrichment processes in the mantle sources for the Rainy Lake area. Consideration of data from the Abitibi belt suggests such enrichment processes in the mantle may have preceded crust-forming events in a wide area of the Superior Province, perhaps by as much as 50–70 Ma.
Oxygen-isotope geochemistry of Archean granitoid gneisses and related rocks in the English River Subprovince, northwestern Ontario
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Whole-rock $δ^{18} O$ values for Archean granitoid gneisses from the southern domain of the English River Subprovince, northwestern Ontario, increase from an average of +6.5 for 3000 Ma old tonalites in the eastern Lac Seul area to an average of +7.9 for 2750–2800 Ma old tonalites, trondhjemites and granodiorites that occur in the Kenora and eastern Lac Seul areas. Still younger granitoid plutons and dykes (2660-2560 Ma) that intrude the older gneisses also have average $δ^{18} O = +7.9$ . These values lie towards the low end of the range known for normal granitoid rocks. Oxygen-isotope data for minerals from the granitoid rocks indicate minor isotopic disequilibrium, but no evidence exists for large-scale depletion in ¹⁸O subsequent to granitoid formation.
Rocks rich in ¹⁸O are abundant only in the northern domain of the English River Subprovince, which is dominated by paragneiss and metasedimentary migmatite ( $δ^{18} O +9−12$ ). Within the Kenora area of the southern domain, however, a remnant supracrustal sequence characterized by a thin metachert/iron formation unit ( $δ^{18} O = +8−10$ ) has been recognized.
The low whole-rock oxygen-isotope values indicate that pre-existing ¹⁸O-rich supracrustal rocks were not involved in the genesis of the 3000 Ma old gneisses and have made only limited, if any, contribution to the magmas that formed the younger units. This conclusion is supported by the low initial Sr-isotope ratios of these rocks (0.7009-0.7027). The oxygen- and strontium-isotope data require that most of the granitoid rocks in the southern domain of the English River Subprovince comprise juvenile or near-juvenile additions to the continental crust.
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Research paperOxygen isotope evidence for the origin of discrete granitoid plutons from the Archean western Wabigoon Belt, northwestern Ontario

Abstract

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Research paper
Oxygen isotope evidence for the origin of discrete granitoid plutons from the Archean western Wabigoon Belt, northwestern Ontario