Ilmenite, magnetite, and peraluminous Mesoproterozoic anorogenic granites of Laurentia and Baltica

Anderson, J. Lawford; Morrison, J.

doi:10.1016/j.lithos.2004.05.008

Cited by 150 publications

(80 citation statements)

References 88 publications

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“…basin formation) in Laurentia are very similar to those observed in Fennoscandia (e.g. Emslie 1978;Windley 1993;Gower and Tucker 1994;Andersson and Morrison 2005), and lend further support to a contiguous active Baltica-Laurentia margin before the Sveconorwegian orogeny (e.g. Romer 1996;Karlstrom et al 2001;.…”

Section: The Onset Of Magmatism Of the Danopolonian Eventsupporting

confidence: 74%

Mesoproterozoic (1.47–1.44 Ga) orogenic magmatism in Fennoscandia; Baddeleyite U–Pb dating of a suite of massif-type anorthosite in S. Sweden

Brander¹

2007

Int J Earth Sci (Geol Rundsch)

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The Jönköping Anorthositic Suite (JAS) in S. Sweden has characteristics typical for (Proterozoic) massiftype anorthosites. The interstitial liquid of these plagioclase-porphyritic rocks solidified at 1,455 ± 6 Ma, as determined by U-Pb isotope analysis of baddeleyite. The JAS developed during a regional 1.47-1.44 event in Fennoscandia that generated widespread mafic magmatism (basalts, and diabase dykes and sills) in the north and emplacement of felsic plutons in the south. The event of 1.47-1.44 Ga magmatism in Fennoscandia largely coincides in age with dynamic high-grade metamorphism in SW Sweden and was probably related to convergent activemargin processes during the Danopolonian orogeny.

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Section: The Onset Of Magmatism Of the Danopolonian Eventsupporting

confidence: 74%

Mesoproterozoic (1.47–1.44 Ga) orogenic magmatism in Fennoscandia; Baddeleyite U–Pb dating of a suite of massif-type anorthosite in S. Sweden

Brander¹

2007

Int J Earth Sci (Geol Rundsch)

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“…Depressed v RMS levels between 1.5 and 1.0 Ga correlate with emplacement of the anorthosite-mangerite-charnockite-A type granite (AMCG) suite unique to Mesoproterozoic and Early Neoproterozoic times (Anderson and Morrison, 2005). Subcrustal temperatures need to reach 1200e1300 C to produce anorthositic magmas and must then be sustained to permit delivery to the upper crust (Vigneresse, 2005); comprehensive weakening of the crust is required to emplace these plutons as large, thin and widely-spaced plutons (Bridgwater et al, 1974).…”

Section: Prolonged V Rms Slowdown and Mesoproterozoic Anorogenic Magmmentioning

confidence: 99%

Continental velocity through Precambrian times: The link to magmatism, crustal accretion and episodes of global cooling

Piper

2013

Geoscience Frontiers

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a b s t r a c tQuasi-integrity of continental crust between Mid-Archaean and Ediacaran times is demonstrated by conformity of palaeomagnetic poles to near-static positions between w2.7e2.2 Ga, w1.5e1.2 Ga and w0.75e0.6 Ga. Intervening data accord to coherent APW loops turning at "hairpins" focused near a continental-centric location. Although peripheral adjustments occurred during Early Proterozoic (w2.2 Ga) and Grenville (w1.1 Ga) times, the crust retained a low order symmetrical crescent-shaped form constrained to a single global hemisphere until break-up in Ediacaran times. Conformity of palaeomagnetic data to specific Eulerian parameters enables definition of a master Precambrian APW path used to estimate the root mean square velocity (v RMS ) of continental crust between 2.8 and 0.6 Ga. A long interval of little polar movement between w2.7 and 2.2 Ga correlates with global magmatic shutdown between w2.45 and 2.2 Ga, whilst this interval and later slowdown at w0.75e0.6 Ga to velocities of <2 cm/year correlate with episodes of widespread glaciation implying that these prolonged climatic anomalies had an internal origin; the reduced input of volcanically-derived atmospheric greenhouse gases is inferred to have permitted freeze-over conditions with active ice sheets extending into equatorial latitudes as established by low magnetic inclinations in glaciogenic deposits. v RMS variations through Precambrian times correspond to the distribution of U-Pb ages in orogenic granitoids and detrital zircons and demonstrate that mobility of continental crust has been closely related to crustal tectonism and incrementation. Both periods of near-stillstand were followed by rapid v RMS recording massive heat release from beneath the continental lid at w2.2 and 0.6 Ga. The first coincided with the Lomagundi-Jatuli isotopic event and led to prolonged orogenesis accompanied by continental flooding and reconfiguration of the crust on the Earth's surface; the second led to continental break-up and instigated the comprehensive Plate Tectonics that has characterised Phanerozoic times. The Mesoproterozoic interval characterised by anorogenic magmatism correlates with low v RMS between w1.5 and 1.1 Ga. Insulation of the sub-continental mantle evidently permitted high temperature melting and weakening of the crustal lid to enable buoyant emplacement of large plutons at high crustal levels during this magmatic event unique to Mesoproterozoic and early Neoproterozoic times.Ó 2012, China University of Geosciences (Beijing) and Peking University. Production and hosting by Elsevier B.V. All rights reserved.

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“…A-type granites and rhyolites are commonly interpreted to be the result of partial melting of continental crust (e.g., Frindt et al 2004, Rämö andHaapala 1995;Patiño Douce 1997;Collins et al 1982;Leeman 1982: Anderson andMorrison 2005;Hughes and McCurry 2002;Christiansen et al 1986;King et al 2001). However, where the isotopic contrast between old crust and mantle is large, it has been argued that a significant percentage (as high as 100%) of the silicic magmas must have come from the mantle (e.g., Bonin 2005;Ewart et al 2004).…”

Section: Production Of Rhyolite By Partial Melting Of Continental Crustmentioning

confidence: 99%

Contrasting origins of Cenozoic silicic volcanic rocks from the western Cordillera of the United States

2007

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Two fundamentally different types of silicic volcanic rocks formed during the Cenozoic of the western Cordillera of the United States. Large volumes of dacite and rhyolite, mostly ignimbrites, erupted in the Oligocene in what is now the Great Basin and contrast with rhyolites erupted along the Snake River Plain during the Late Cenozoic. The Great Basin dacites and rhyolites are generally calc-alkaline, magnesian, oxidized, wet, cool (<850°C), Sr-and Al-rich, and Fe-poor. These silicic rocks are interpreted to have been derived from mafic parent magmas generated by dehydration of oceanic lithosphere and melting in the mantle wedge above a subduction zone. Plagioclase fractionation was minimized by the high water fugacity and oxide precipitation was enhanced by high oxygen fugacity. This resulted in the formation of Si-, Al-, and Sr-rich differentiates with low Fe/Mg ratios, relatively low temperatures, and declining densities. Magma mixing, large proportions of crustal assimilation, and polybaric crystal fractionation were all important processes in generating this Oligocene suite. In contrast, most of the rhyolites of the Snake River Plain are alkaline to calc-alkaline, ferroan, reduced, dry, hot (830-1,050°C), Sr-and Al-poor, and Nb-and Fe-rich. They are part of a distinctly bimodal sequence with tholeiitic basalt. These characteristics were largely imposed by their derivation from parental basalt (with low f H 2 O and low f O 2 ) which formed by partial melting in or above a mantle plume. The differences in intensive parameters caused early precipitation of plagioclase and retarded crystallization of Fe-Ti oxides. Fractionation led to higher density magmas and mid-crustal entrapment. Renewed intrusion of mafic magma caused partial melting of the intrusive complex. Varying degrees of partial melting, fractionation, and minor assimilation of older crust led to the array of rhyolite compositions. Only very small volumes of distinctive rhyolite were derived by fractional crystallization of Fe-rich intermediate magmas like those of the Craters of the Moon-Cedar Butte trend.

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Ilmenite, magnetite, and peraluminous Mesoproterozoic anorogenic granites of Laurentia and Baltica

Cited by 150 publications

References 88 publications

Mesoproterozoic (1.47–1.44 Ga) orogenic magmatism in Fennoscandia; Baddeleyite U–Pb dating of a suite of massif-type anorthosite in S. Sweden

Mesoproterozoic (1.47–1.44 Ga) orogenic magmatism in Fennoscandia; Baddeleyite U–Pb dating of a suite of massif-type anorthosite in S. Sweden

Continental velocity through Precambrian times: The link to magmatism, crustal accretion and episodes of global cooling

Contrasting origins of Cenozoic silicic volcanic rocks from the western Cordillera of the United States

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