40Ar∗ loss in experimentally deformed muscovite and biotite with implications for 40Ar/39Ar geochronology of naturally deformed rocks

Cosca, Michael A.; Stünitz, Holger; Bourgeix, A.L.; Lee, John P.

doi:10.1016/j.gca.2011.10.012

Cited by 62 publications

(63 citation statements)

References 38 publications

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“…1 and 12). Indeed, from roughly north to south, the I Sr values increase while the εNd(T) decrease from the Rostrenen (316 ± 3 Ma, U-Pb zircon; Euzen, 1993), Pontivy (344 ± 8 Ma, Rb-Sr whole-rock isochron; Bernard-Griffiths et al, 1985;311 ± 2 Ma, 40 Ar/ 39 Ar muscovite; Cosca et al, 2011), Lizio (316 ± 6 Ma, U-Pb zircon; Tartèse et al, 2011a), Questembert (316 ± 3 Ma, U-Pb zircon; Tartèse et al, 2011b) to the Guérande granite (309.7 ± 1.3 Ma, U-Pb zircon and monazite; this study, see part 9.4). We can propose three hypotheses at two different spatial scales to account for this trend:…”

Section: Sourcementioning

confidence: 99%

Tectonic record, magmatic history and hydrothermal alteration in the Hercynian Guérande leucogranite, Armorican Massif, France

Ballouard

Boulvais

Poujol

et al. 2015

Lithos

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Section: Sourcementioning

confidence: 99%

Tectonic record, magmatic history and hydrothermal alteration in the Hercynian Guérande leucogranite, Armorican Massif, France

Ballouard

Boulvais

Poujol

et al. 2015

Lithos

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“…Villa, 2015;2016). Since latest deformation in this sample occurred below the ideal Ar closure temperature (385 °C vs. ≥420 °C, dependent upon grain size and cooling rate), the distribution of 40 Ar/ 39 Ar dates preserved in this sample more likely record deformationinduced Ar loss via syn-kinematic dynamic recrystallization and/or internal deformation of white mica grains, resulting in the observed complex/patchy Ar distribution pattern (Cosca et al, 2011).…”

mentioning

confidence: 88%

“…However, an alternative interpretation of 40 Ar loss via grain rim recrystallization and intragrain deformation in the absence of thermal diffusion is also possible (Mulch et al, 2005;Cosca et al, 2011). For example, Mulch et al (2005) studied mylonite-hosted mica fish and found a core to rim date relationship that they attributed to recrystallization during deformation.…”

mentioning

confidence: 99%

Influence of deformation and fluids on Ar retention in white mica: Dating the Dover Fault, Newfoundland Appalachians

Kellett

Warren

Larson

et al. 2016

Lithos

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“…Harrison et al 2009;Forster & Lister 2010Warren et al 2012a), deformation (e.g. Hames & Cheney 1997;Mulch et al 2002;Kramer et al 2003;Cosca et al 2011) and the availability and nature of intergranular fluids (e.g. Rubie 1986Rubie , 1990Kühn et al 2000;Glodny et al 2008;Smye et al 2013).…”

Section: Diffusion Rates: Experiments and Models Versus Naturementioning

confidence: 99%

On the significance of short-duration regional metamorphism

Viete

Lister

2016

JGS

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Short-duration regional metamorphism is a recently observed and poorly understood phenomenon in metamorphic geology. In this review, it is defined as metamorphism on time scales that limit length scales (of the associated thermal anomaly) to significantly less than the thickness of the orogenic crust (<10 myr) or subducted oceanic lithosphere (<5 myr). Without appealing to exceptional heat sources, thermal models have been unable to account for peak metamorphic temperature during collisional orogenesis and subduction. This observation, combined with restricted time scales for regional metamorphism, suggests that metamorphic facies series can record atypical and transient thermal conditions (related to punctuated and localized heat advection and/or production), rather than normal, ambient conditions for the tectonic setting to which they are allied. Highprecision geochronology can resolve short-duration metamorphic estimates of 1 -10 myr. However, diffusion geospeedometry typically yields extremely short metamorphic durations (<1 myr); tools in metamorphic geology may have matured to the point that the discipline is beginning to recognize episodicity and criticality in deep processes. New, very high-precision petrochronology techniques offer great potential to probe the veracity of extremely short metamorphic durations being obtained from diffusion geospeedometry. Benchmarking of these new very high-precision petrochronology techniques must become a priority for metamorphic geology.Received 26 May 2016; revised 2 October 2016; accepted 27 October 2016Early interpretations of the geological record leant heavily on catastrophism. As geology matured as a science, uniformitarianism came to supersede catastrophism. Uniformitarianism offers a more sophisticated, logical framework for interpretation of the rock record within the context of current and observable processes. However, the grand success of the uniformitarian philosophy has also resulted in a propensity toward interpretation of deep (and thus unobservable) geological phenomena in terms of slowly evolving or steady-state processes. A notable example of this preference for gradualism in deep processes has been ideas for the origins of regional metamorphism and metamorphic facies series, and implications for the nature of tectonism. Barrow (1893Barrow ( , 1912 was the first to map regional metamorphism on the basis of diagnostic mineral assemblages. His Barrovian metamorphic sequence, exposed in NE Scotland, comprises a series of 'isograds' marking the first appearance of chlorite, biotite, garnet, staurolite, kyanite and sillimanite in pelitic lithologies, in the direction of increasing metamorphic grade. Regional metamorphism recorded by Barrovian-type isograds defines intermediate pressure/temperature (P/T ) conditions (575 -1250°C GPa Barrow (1893) originally proposed that his Barrovian metamorphism resulted from magmatic advection of heat from depth. Following development of the theory of plate tectonics, numerous models were proposed for the ori...

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40Ar∗ loss in experimentally deformed muscovite and biotite with implications for 40Ar/39Ar geochronology of naturally deformed rocks

Cited by 62 publications

References 38 publications

Tectonic record, magmatic history and hydrothermal alteration in the Hercynian Guérande leucogranite, Armorican Massif, France

Tectonic record, magmatic history and hydrothermal alteration in the Hercynian Guérande leucogranite, Armorican Massif, France

Influence of deformation and fluids on Ar retention in white mica: Dating the Dover Fault, Newfoundland Appalachians

On the significance of short-duration regional metamorphism

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