Geology and U–Pb geochronology of the Neoarchean Snare River terrane: tracking evolving tectonic regimes and crustal growth mechanisms

Abstract

U–Pb zircon crystallization ages determined by isotope dilution – thermal ionization mass spectrometry (ID–TIMS) and laser ablation microprobe – inductively coupled plasma – mass spectrometry (LAM–ICP–MS) for 13 intrusive units in the Neoarchean Snare River terrane (SRT) provide tight constraints on the timing of crust formation and orogenic evolution. Seven metaluminous plutons were emplaced over ~80 Ma from ca. 2674 to 2589 Ma, whereas six peraluminous bodies were emplaced in a ~15 Ma interval from ca. 2598 to 2585 Ma. A detrital zircon study yielded an age spectrum with peaks correlative with known magmatic events in the Slave Province, with the ca. 2635 Ma age of the youngest detrital zircon population providing a maximum estimate for the onset of sedimentation. This age contrasts with evidence for pre-2635 Ma sedimentation elsewhere in the SRT, indicating that sedimentation was protracted and diachronous. Evolution of the SRT can be subdivided into four stages: (i) 2674–2635 Ma — formation of a metaluminous protoarc in a tonalite–trondhjemite–granodiorite (TTG) – granite–greenstone tectonic regime (TR1) and coeval with early turbidite sedimentation; (ii) 2635–2608 Ma — continued turbidite sedimentation, D1/M1 juxtaposition of turbidites and protoarc lithologies prior to ~2608 Ma, and metaluminous granitoid plutonism; (iii) 2608–2597 Ma — onset of TR2, collision of Snare protoarc with Central Slave Basement Complex, D2/M2 crustal thickening and mid-crustal granulite-facies metamorphism, sychronous with metaluminous and peraluminous plutonism; and (iv) 2597–2586 Ma — orogenic collapse, D3/M3 mid-crustal uplift, granulite-facies metamorphism, and waning metaluminous and peraluminous plutonism. The distribution of igneous rocks yields an "orogenic stratigraphy" with an older upper crust underlain by a younger synorogenic mid-crust. These data can be used to provide constraints for the interpretation of the Slave – Northern Cordillera Lithospheric Evolution (SNORCLE) Lithoprobe transect.

Are Wilson Cycles preserved in Archean cratons? A comparison of the North China and Slave cratons

“…Seismic surveys (Cook et al 1999;van der Velden 2007) have shown that the Anton terrane (CSST) is a westward-tapering wedge-shaped indentor slicing through the Snare River terrane, which is interpreted to have sutured to the CSST (Anton terrane) at 2630-2620 Ma (Bennett et al 2005). Eastward-directed subduction of the Snare River terrane beneath the CSST preceding this collision is thought to be responsible for ca.…”

Archaean sedimentary sequences of the Slave craton

“…2.67e2.58 Ga Snare River terrane is composed of bimodal volcanic sequences, turbidite successions and synvolcanic plutons that are located in the southwestern portion of the Slave Province (Pehrsson and Villeneuve, 1999;Bennett et al, 2005). The Snare River domain is inferred to have collided with the Central Slave superterrane between 2.63 and 2.62 billion years ago (Pehrsson and Villeneuve, 1999;Bennett et al, 2005).…”

“…Plutonic suites, linear greenstone belts, and a variety of sedimentary successions comprise the ca. 2.58e4.03 Ga (Bowring et al, 1989;van Breemen et al, 1992;Isachsen and Bowring, 1997;Bennett et al, 2005) Slave Province. Several features distinguish the Slave Province from most Archaean cratons, including a higher felsic/mafic volcanic rock ratio, more sedimentary than volcanic rocks, and abundant evolved potassium-rich granites (Henderson, 1981;Padgham and Fyson, 1992).…”

A field, geochemical and geochronological perspective on the origin of granitoids and mafic volcanic rocks in the Wecho River area and the nature of ancient crust in the southwestern Slave Province, NWT

“…These are clastic sedimentary rocks, dominantly greywackes, interpreted to be turbidite sequences. These rocks cover approximately 40% of the craton, ranging in metamorphic facies from greenschist to upper amphibolite with rare granulite occurrences, such as those in the Snare River area (Jackson, 2003 andBennett et al, 2005). There are three ages of sedimentation for the Yellowknife Supergroup: the >2680 Ma George Lake turbidites (van Breeman et al, 1992), the 2660-2680 Ma Burwash and equivalent formations and a younger formation dated at <2630 Ma, locally known as the Damoti formation in the Indin Lake area, but also found at Russell Lake (Pehrsson and Villeneuve, l999;Bennett et al, 2005;.…”

“…2680 Ma Cotterhill gneiss complex in the Indin Lake area (Pehrsson and Villeneuve, 1999) as well as the ca. 2680 to 2650 Ma trondjhemite-granodiorite-tonalite (TTG) plutons of the Snare River area (Bennett et al, 2005) are part of the pre-deformational granitoid group. The Anton Complex, once interpreted as part of the CSBC, is composed of 2630 to 2638 Ma foliated granodiorites and granites.…”