High-resolution dating of granite petrogenesis and deformation in a lower crustal shear zone: Athabasca granulite terrane, western Canadian Shield

Apparent partial loss 40Ar/39Ar age spectra of hornblende from the Palaeoproterozoic Lapland-Kola orogen (arctic European Russia): insights from numerical modelling and multi-method in-situ micro-sampling geochronology

“…Fabricforming minerals record the changing physical conditions along P-T-d-t paths. This is also the case for polygenetic Th-and U-bearing accessory minerals like monazite, xenotime, euxenite-polycrase, allanite and zircon (Crowley and Ghent, 1999;Cocherie et al, 2005;Dahl et al, 2005;Dumond et al, 2008;Li et al, 2008;Suzuki and Kato, 2008;Bosse et al, 2009). Fluid-assisted recrystallisation that affected ionic bonds in minerals, consequently, played a paramount role during exchange or loss of radiogenic daughter isotopes (Wijbrans and McDougall, 1986;Miller et al, 1991;Villa 1998;Kerrich and Ludden 2000;de Jong et al, 2001;de Jong, 2003).…”

“…thin sections using CHIME (Suzuki and Adachi, 1991;Montel et al, 1996) offer a ten times higher spatial resolution (Cocherie et al, 2005;Dahl et al, 2005;Dumond et al, 2008;Kusiak and Lekki, 2008;Suzuki and Kato, 2008).…”

Dating Metasomatism: Monazite and Zircon Growth during Amphibolite Facies Albitization

“…The details of analytical procedures, including count times, standards, and a list of spectrometers, follow those laid out in Appendix A of Dumond [40], Williams et al [41], and Jercinovic [42]. Background corrections followed the multipoint background method of Allaz et al, [43].…”

“…The majority of these lithologies have Archean protoliths, and along the northwestern margin of the Wyoming province, they contain evidence for at least two high temperature thermotectonic events: the enigmatic 2500-2450 Ma Tobacco Roots-Tendoy orogeny [20,[25][26][27] and the 1800-1710 Ma Big Sky orogeny [20,22], interpreted as the results of the Wyoming province docking with the rest of the Archean core of Laurentia during the amalgamation of supercontinent Nuna [28,29]. To the southeast of the rocks overprinted by Paleoproterozoic thermotectonism, K-Ar and 40 Ar- 39 Ar thermochronology indicates that the Archean rocks have not been thermally overprinted since the Neoarchean (Figure 1A,B; [30][31][32]). …”

Mechanisms of metasomatic reactions

“…Metasomatic processes can include ore mineralization (Wilkinson and Kesler 2007); metasomatically induced alteration of oceanic lithosphere (Hopson et al 2008); mass transport in and alteration of subducted oceanic crust and overlying mantle wedge (Zack and John 2007), which has subsequent implications regarding mass transport, fluid flow, and volatile storage in the lithospheric mantle overall (Mukasa et al 2007), as well as both regional (Ordonez et al 2008) and localized crustal metamorphism (Harlov et al 2006). Metasomatic alteration of accessory minerals such as zircon (Geisler et al 2007) or monazite (Dumond et al 2008) can allow for the dating of metasomatic events as well as give additional information regarding the chemistry of the fluids responsible.…”