Journal of Metamorphic Geology

Journal: Journal of Metamorphic Geology

Abbreviation

J. metamorph. geol.

Publisher

Wiley-Blackwell

ISSN

0263-4929
1525-1314

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Publications 1 - 10 of 35

Constraints on the Palaeoproterozoic tectono-metamorphic evolution of the Lewisian Gneiss Complex, NW Scotland: Implications for Nuna assembly
Volante, Silvia; Dziggel, Annika; Walters, Jesse B.; et al. (2024)
Journal of Metamorphic Geology
Despite extensive investigation, the tectono-thermal evolution of the Archean crust in the Lewisian Gneiss Complex in NW Scotland (LGC) is debated. Most U–Pb zircon geochronological and metamorphic studies have focused on rocks from the central region of the mainland LGC, where granulite facies assemblages associated with the oldest (Badcallian) tectono-metamorphic event at c. 2.75 Ga are overprinted by younger amphibolite facies assemblages related to the Inverian (c. 2.5 Ga) and subsequent Laxfordian (c. 1.9–1.65 Ga) tectono-thermal events. In the southern and northern regions of the mainland LGC, deformation and metamorphism associated with the Laxfordian event are pervasive, although the timing and conditions are poorly constrained. Here, we present new field, petrographic and structural data, U–Pb zircon and titanite geochronology and phase equilibrium modelling of amphibolite samples from the northern and southern regions. Our field observations show that in both regions, pre-Laxfordian structures are significantly reworked by steep NW-striking fabrics that are themselves pervasively overprinted by co-axial deformation and amphibolite facies metamorphism related to the Laxfordian event. In situ U–Pb titanite geochronology yields Laxfordian ages of 1853 ± 20 Ma in the southern region (P = 6–8 kbar and T = 640–690°C) and 1750 ± 20 Ma and 1776 ± 10 Ma in the northern region (P = 6–7.5 kbar and T = 740–760°C). While U–Pb dating of zircon rims from felsic gneisses in the central region shows a dominant Inverian metamorphic overprint at c. 2500 Ma, zircon rims in felsic gneisses from the northern and southern regions commonly yield Laxfordian dates as young as c. 1800 Ma. Combined, the results support the idea that, during the Palaeoproterozoic, the central region of the LGC acted as low-strain domain, in which intense deformation and metamorphism were restricted to crustal-scale shear zones. By contrast, in the southern and northern regions, early (c. 1.85 Ga) and late (c. 1.75 Ga) Laxfordian deformation and fluid-mediated metamorphism were much more pervasive and at higher P–T conditions than previously proposed. The diachronous Laxfordian evolution of the southern and northern regions indicate that they reflect early and late snapshots of collisional to transpressional tectonics in the mainland LGC. The long-lasting Laxfordian evolution documents the collision of the Rae and North Atlantic cratons during the Palaeoproterozoic amalgamation of the supercontinent Nuna, with implications for the palaeogeographic configuration of NW Scotland during Palaeoproterozoic Nuna.
Grain-scale pressure variations and chemical equilibrium in high-grade metamorphic rocks
Tajcmanova, L.; Podladchikov, Y.; Powell, R.; et al. (2014)
Journal of Metamorphic Geology
Tectonic overpressure and underpressure in lithospheric tectonics and metamorphism
Gerya, Taras (2015)
Journal of Metamorphic Geology
Influence of tectonic overpressure on P-T paths of HP-UHP rocks in continental collision zones
Li, Z. H.; Gerya, Taras; Burg, Jean-Pierre (2010)
Journal of Metamorphic Geology
Deviations from lithostatic pressure during metamorphism: fact or fiction?
Tajčmanová, L. (2015)
Journal of Metamorphic Geology
Geodynamic regimes of subduction under an active margin
Gerya, Taras; Meilick, F.I. (2011)
Journal of Metamorphic Geology
Current challenges for explaining (ultra)high-pressure tectonism in the Pennine domain of the Central and Western Alps
Schenker, F.L.; Schmalholz, S.M.; Moulas, E.; et al. (2015)
Journal of Metamorphic Geology
Phase equilibria constraints on melting of stromatic migmatites from Ronda (S. Spain): insights on the formation of peritectic garnet
Bartoli, O.; Tajcmanova, L.; Cesare, B.; et al. (2013)
Journal of Metamorphic Geology
Exhumation mechanisms of melt-bearing ultrahigh pressure crustal rocks during collision of spontaneously moving plates
Sizova, E.; Gerya, Taras; Brown, M. (2012)
Journal of Metamorphic Geology
Coexistence of lawsonite-bearing eclogite and blueschist
Vitale Brovarone, A.; Groppo, C.; Hetényi, György; et al. (2011)
Journal of Metamorphic Geology

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Journal: Journal of Metamorphic Geology

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