The Pikwitonei Granulite Domain, Manitoba: a giant Neoarchean high-grade terrane in the northwest Superior ProvinceThis article is one of a series of papers published in this Special Issue on the theme of Geochronology in honour of Tom Krogh.N. Machado, T.E. Krogh, and W. Weber are deceased.

Abstract

The Pikwitonei Granulite Domain located at the northwestern margin of the Superior Province is one of the largest Neoarchean high-grade terranes in the world, with well-preserved granulite metamorphic assemblages preserved in a variety of lithologies, including enderbite, opdalite, charnockite, and mafic granulite. U–Pb geochronology has been attempted to unravel the protolith ages and metamorphic history of numerous lithologies at three main localities; Natawahunan Lake, Sipiwesk Lake, and Cauchon Lake. The U–Pb age results indicate that some of the layered enderbite gneisses are Mesoarchean (3.4–3.0 Ga) and the more massive enderbites are Neoarchean. The high-grade metamorphic history of the Pikwitonei Granulite Domain is complex and multistage with at least four episodes of metamorphic zircon growth identified: (1) 2716.1 ± 3.8 Ma, (2) 2694.6 ± 0.6 Ma, (3) 2679.6 ± 0.9 Ma, and (4) 2642.5 ± 0.9 Ma. Metamorphic zircon growth during episodes 2 and 3 are interpreted to be regional in extent, corresponding to M1 amphibolite- and M2 granulite-facies events, respectively, consistent with previous field observations. The youngest metamorphic episode at 2642.5 Ma is only recognized at southern Cauchon Lake, where it coincides with granite melt production and possible development of a major northeast-trending deformation zone. The timing and multistage metamorphic history recorded in the Pikwitonei Granulite Domain is similar to most Superior Province high-grade terranes and marks a fundamental break in Archean crustal evolution worldwide at the termination of prolific global Neoarchean greenstone belt formation.

Deep Crustal Structure and Model of Neorchaean Evolution of the North American Craton

“…История роста циркона в эндербитах и гранулитах фиксирует несколько эпизодов: 2.74-2.72, 2.70-2.69, 2.68, 2.66-2.64 и 2.63-2.59 млрд лет. Пиковые значения метаморфизма датированы 2.64 млрд лет [Mezger et al, 1990;Heaman et al, 2011]. По мнению К. Мезгера с соавторами, метаморфизм гранулитовой фации непосредственно связан с внедрением высокотемпературной (>1100 °C) ортопироксенсодержащей эндербитовой магмы.…”

Neoarchean Mantle-derived Magmatism within the Repulse Bay Block, Melville Peninsula, Nunavut: Implications for Archean Crustal Extraction and Cratonization

“…These lithologies were affected by a multistage metamorphic history at ca. 2716, 2694, 2680 and 2643 Ma, of which the generation of zircon at 2694 and 2680 Ma corresponds to amphibolite-and granulite-facies metamorphism, respectively (Heaman et al 2011). Large scale Neoarchean plutons similar to those observed in the RBb have also been identified across Hudson Bay, in the Minto block of the northern Superior Province (Bédard 2003).…”

“…Based on a compilation of data from high grade terranes in the Superior Province including the Pikwitonei, Minto block, Split Lake block, Quetico, English River and Opatica domains, Heaman et al (2011) demonstrated that Neoarchean magmatism and high grade (high T/low-moderate P) multi-stage metamorphism follows the development of 2.8-2.7 Ga granite-greenstone belts. Furthermore, Whalen et al (2004) demonstrated that a compositional continuum exists between Neoarchean monzogranite to granodiorite plutonism and sanukitoid plutonism within the Superior Province, indicating that felsic granitoid rocks may be petrogenetically linked to mantle-derived magmatism.…”

“…Davis et al 2005;Boily et al 2009;Heaman et al 2011). Granulite terranes can preserve regional scale, pyroxene-bearing, massif-type calc-alkalic intrusions (Fyfe 1973;Rudnick and Fountain 1995).…”

“…The generation of Neoarchean charnockite intrusions occurred in a period that recorded a fundamental break in Archean crustal evolution worldwide: the cessation of greenstone belt and TTG formation (e.g. Heaman et al 2011). These hot, CO 2 -laden charnockite intrusions (containing igneous ortho-and clinopyroxene) have been described as the driving force for the formation of granulite terranes during their emplacement (Frost and Frost 2008) and may be critical in Neoarchean crust stabilization.…”