Table 2.

Worldwide examples of regional metamorphism for which diffusion geospeedometry produced a metamorphic duration estimate of <10 myr

LocationMetamorphic faciesApproximate T (°C), P (GPa)AgeDuration, Duration used in Figure 1 (kyr)Diffusion systemArrhenius parametersReference
Bergen Arcs, SW NorwayEclogite, Franciscan720, 2.0Scandian, c. 425 Ma17 – 32 kyr, 25Ca, Fe, Mg in grtGanguly et al. (1998)Raimbourg et al. (2007)
Bergen Arcs, SW NorwayEclogite, Franciscan525, 1.9Scandian, c. 423 Ma18 kyr, 18Ar in hbl, phlGiletti (1974), Harrison (1981)Camacho et al. (2005)
Tauern Window, E Alps, AustriaEclogite, Franciscan570, 1.7Alpine, c. 34 Ma100 – 500 kyr, 300Fe, Mn in grtLoomis et al. (1985), Chakraborty & Ganguly (1992)Dachs & Proyer (2002)
NW Connecticut, New England, NE USAEclogite, Sanbagawan710, 1.45Taconian, c. 455 MaComparative (<10), 10*Mn in grtn.a.Chu et al. (2016)
Yukon–Tanana Terrane, S Yukon, CanadaEclogite, Sanbagawan690, 1.5Klondike, c. 259 Ma200 kyr, 200Ca in grtSchwandt et al. (1996)Perchuk et al. (1999)
Eastern Vermont, New England, NE USAGreenschist, Barrovian450, 0.75Acadian, c. 364 Ma<1 – 200 yr, 0.1Fe in calMüller et al. (2012)Ferry et al. (2015)
Region of Moine Thrust, N ScotlandEpidote amphibolite, Barrovian590, 0.7Scandian, c. 425 Ma<100 – 200 kyr, 100Ti in qtzCherniak et al. (2007)Ashley et al. (2015)
Middle Austroalpine Unit, E Alps, AustriaEpidote amphibolite (overprint), Barrovian600, 1.0Eo-Alpine, c. 94 Ma800 – 900 kyr, 850Ca, Fe, Mg, Mn in grtChakraborty & Ganguly (1992)Faryard & Chakraborty (2005)
Central Vermont, New England, NE USAEpidote amphibolite, Barrovian640, 1.0Acadian, c. 353 Ma0.12 – 1.8 myr, 1000Mn in grtChakraborty & Ganguly (1992)Spear (2014)
Central Vermont, New England, NE USAAmphibolite, Barrovian580, 0.51Acadian, c. 353 Ma0.2 – 2 myr, 1000Ti in qtzCherniak et al. (2007)Spear et al. (2012)
Moldanubian Zone, Bohemian Massif, Světlík area, Czech RepublicAmphibolite (overprint), Barrovian710, 0.73Variscan, c. 375 Ma<200 kyr, 100Fe in grtChakraborty & Ganguly (1992)O'Brien & Vrana (1995)
Moldanubicum, Bohemian Massif, NW Ottenschlag, Lower AustriaAmphibolite (overprint), Barrovian725, 0.8Variscan, c. 375 Ma100 – 700 kyr, 500Ca, Fe, Mg in grtChakraborty & Ganguly (1992)O'Brien (1997)
Blyb Metamorphic Complex, Great Caucasus, RussiaAmphibolite (overprint), Barrovian660, 0.8Variscan, c. 310 Ma100 – 500 kyr, 300Mg in grtChakraborty & Rubie (1996)Perchuk & Philippot (2000)
Blyb Metamorphic Complex, Great Caucasus, RussiaAmphibolite (overprint), Barrovian660, 0.8Variscan, c. 310 Ma0.5 – 2.5 myr, 1000Mg in grtChakraborty & Rubie (1996)Perchuk & Philippot (1997)
Barrovian Series, E ScotlandAmphibolite, Barrovian640, 0.59Grampian, c. 470 MaComparative (10 – 100 kyr episodes), 50†Mn, Ca in grtn.a.Viete et al. (2011b)
Barrovian Series, E ScotlandAmphibolite, Barrovian660, 0.57Grampian, c. 470 Ma30 – 200 kyr, 100Ca, Fe, Mg, Mn in grtCarlson (2006)Ague & Baxter (2007)
Barrovian Series, E ScotlandAmphibolite, Barrovian600, 0.5Grampian, c. 470 Ma<2 myr, 750Ca, Fe, Mg, Mn in grtChu & Ague (2015)Chu & Ague (2015)
Barrovian Series, E ScotlandAmphibolite, Barrovian660, 0.6Grampian, c. 470 MaComparative (10–20 times longer than Himalayan), n.a.‡Mn in grtn.a.Ayres & Vance (1997)
Higher Himalayan Crystalline Series, Zanskar Himalaya, NW IndiaAmphibolite, Barrovian690, 1.0Himalayan, c. 33 MaComparative (10–20 times shorter than Barrovian), n.a.‡Mn in grtn.a.Ayres & Vance (1997)
Maine, New England, NE USAGreenschist, Buchan450, 0.35Acadian, c. 364 Ma<1 – 200 yr, 0.1Fe in calMüller et al. (2012)Ferry et al. (2015)
Barrovian Series, E ScotlandGreenschist, Buchan475, 0.33Grampian, c. 470 Ma1 – 10 myr, 5000Ar in wmHarrison et al. (2009)Viete et al. (2011a)
Barrovian Series, E ScotlandAmphibolite, Buchan565, 0.4Grampian, c. 470 Ma200 – 500 kyr, 300Sr in apCherniak & Ryerson (1993)Ague & Baxter (2007)

Information is provided on location, metamorphic facies and facies series, approximate metamorphic PT conditions, age, diffusion system, Arrhenius parameters used and reference. Mineral abbreviations after Kretz (1983); wm, white mica; n.a., not applicable.

*Compared with diffusion length scale over 1 myr at 660°C.

†Metamorphic episodes of 10 – 100 kyr punctuate the 1 – 10 myr Barrovian regional metamorphism.

‡Relative length scales of diffusion suggest that Barrovian metamorphism in Scotland developed over a duration 10–20 times longer than Himalayan Barrovian-type metamorphism.