Variscan migmatites, eclogites and garnet-peridotites of the Ulten zone, Eastern Austroalpine system

Godard, Gaston; Martin, Silvana; Prosser, Giacomo; Kiénast, Jean-Robert; Morten, Lauro

doi:10.1016/0040-1951(95)00145-x

Cited by 75 publications

(46 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…A nearly equal proportion of K-feldspar and plagioclase and a low proportion of quartz in the quartzo-feldspathic layers are consistent with crystallization of a granitic melt produced by partial melting of metapelites (Gilotti and Elvevold, 2002;Lang and Gilotti, 2007). The presence of antiperthitic feldspar in the granitic leucosomes indicates crystallization of Or-rich plagioclase from a melt at relatively high temperature (Spear, 1993;Godard et al, 1996;Gilotti and Elvevold, 2002) and subsequent exsolution. These macroscopic and microscopic observations provide strong evidence for the partial melting of the host paragneisses and amphibolites in both the ASRR and GS complex belts.…”

Section: Evidence For Partial Melting In the Asrr And Gs Complex Beltmentioning

confidence: 63%

Multiple partial melting events in the Ailao Shan–Red River and Gaoligong Shan complex belts, SE Tibetan Plateau: Zircon U–Pb dating of granitic leucosomes within migmatites

Liu

Wang

Liu

et al. 2015

Journal of Asian Earth Sciences

View full text Add to dashboard Cite

Section: Evidence For Partial Melting In the Asrr And Gs Complex Beltmentioning

confidence: 63%

Multiple partial melting events in the Ailao Shan–Red River and Gaoligong Shan complex belts, SE Tibetan Plateau: Zircon U–Pb dating of granitic leucosomes within migmatites

Liu

Wang

Liu

et al. 2015

Journal of Asian Earth Sciences

View full text Add to dashboard Cite

“…Off-craton Basalt Cenozoic Proterozoic Henjes Kunst and Altherr (1992) Lashaine and Labait, Tanzania Craton Ankaramite and carbonitite Cenozoic Proterozoic Reid et al (1975), Rhodes and Dawson (1975), Ridley and Dawson (1975), Bishop et al (1978), Henjes Kunst and Altherr (1992) Hunter and Smith (1981), Ehrenberg (1982), Smith and Ehrenberg (1984), Smith et al (1991), Roden Song et al (2004Song et al ( , 2005Song et al ( , 2007 Dabie-Sulu, China Massif Eclogite and gneiss Mesozoic Mesozoic Zhang et al (1994Zhang et al ( , 2000bZhang et al ( , 2003Zhang et al ( , 2004aZhang et al ( , b, 2005Zhang et al ( , 2007c, Zhang and Liou (1998), Liu et al (1995), Hacker et al (1997), Liou and Zhang (1998), Yang and Jahn (2000), You et al (2000), Yang (2003) (1987), Godard et al (1996), Rampone and Morten (2001), Godard and Martin (2000), Nimis and Morten (2000) Scandian, Sweden Lens Gneiss and schist Paleozoic Archean Brueckner et al (2004) Bohemian, Austria and Czech…”

Section: Marsabit and Chyulu Kenyamentioning

confidence: 98%

Geochemical syntheses among the cratonic, off-cratonic and orogenic garnet peridotites and their tectonic implications

Zhang

Tang

et al. 2010

Int J Earth Sci (Geol Rundsch)

View full text Add to dashboard Cite

Garnet-bearing mantle peridotites, occurring as either xenoliths in volcanic rocks or lenses/massifs in high-pressure and ultrahigh-pressure terrenes within orogens, preserve a record of deep lithospheric mantle processes. The garnet peridotite xenoliths record chemical equilibrium conditions of garnet-bearing mineral assemblage at temperatures (T) ranging from *700 to 1,400°C and pressures (P) [ 1. 6-8.9 GPa, corresponding to depths of *52-270 km. A characteristic mineral paragenesis includes Cr-bearing pyropic garnet (64-86 mol% pyrope; 0-10 wt% Cr 2 O 3 ), Cr-rich diopside (0.5-3.5 wt% Cr 2 O 3 ), Al-poor orthopyroxene (0-5 wt% Al 2 O 3 ), high-Cr spinel (Cr/(Cr ? Al) 9 100 atomic ratio = 2-86) and olivine (88-94 mol% forsterite). In some cases, partial melting, re-equilibration involving garnet-breakdown, deformation, and mantle metasomatism by kimberlitic and/or carbonatitic melt percolations are documented. Isotope model ages of Archean and Proterozoic are ubiquitous, but Phanerozoic model ages are less common. In contrast, the orogenic peridotites were subjected to ultrahigh-pressure (UHP) metamorphism at temperature ranging from *700 to 950°C and pressure [3.5-5.0 GPa, corresponding to depths of [110-150 km. The petrologic comparisons between 231 garnet peridotite xenoliths and 198 orogenic garnet peridotites revealed that (1) bulk-rock REE (rare earth element) concentrations in xenoliths are relatively high, (2) clinopyroxene and garnet in orogenic garnet peridotites show a highly fractionated REE pattern and Ce-negative anomaly, respectively, (3) Fo contents of olivines for off-cratonic xenolith are in turn lower than those of orogenic garnet and cratonic xenolith but mgnumber of garnet for orogenic is less than that of offcratonic and on-cratonic xenolith, (4) Al 2 O 3 , Cr 2 O 3 , CaO and Cr# of pyroxenes and chemical compositions of whole rocks are very different between these garnet peridotites, (5) orogenic garnet peridotites are characterized by low T and high P, off-cratonic by high T and low P, and cratonic by medium T and high P and (6) garnet peridotite xenoliths are of Archean or Proterozoic origin, whereas most of orogenic garnet peridotites are of Phanerozoic origin. Taking account of tectonic settings, a new orogenic garnet peridotite exhumation model, crustmantle material mixing process, is proposed. The composition of lithospheric mantle is additionally constrained by comparisons and compiling of the off-cratonic, oncratonic and orogenic garnet peridotite.

show abstract

“…In the Austrides of northern Italy, numerous small peridotite bodies (<300 m x 100 m) occur in Austroalpine high-grade garnet-kyanite paragneiss, orthogneiss, and migmatite in the Nonsberg area, Ultental, between the Non and Ultimo valleys (Morten and Obata, 1983;Obata and Morten, 1987;Godard et al, 1996). The perido tites are divided into: (a) coarse-grained, protogranular spinel lherzolite, partly transformed to garnet lherzolite, and (b) fine-grained, porphyroclastic to equigranular garnet lherzolite, which contains amphibole and, locally, spinel inclusions in garnet.…”

Section: European Variscidesmentioning

confidence: 99%

Garnet Peridotites in Eurasian High-Pressure and Ultrahigh-Pressure Terranes: A Diversity of Origins and Thermal Histories

Medaris

1999

International Geology Review

View full text Add to dashboard Cite

Garnet peridotites and pyroxenites have been reported from 11 of the 15 or so high-pressure/ ultrahigh-pressure (HP/UHP) terranes in Eurasia. Most of these ultramafic rocks are Mg-Cr types, derived from depleted upper mantle, but some are more Fe-rich and originated by crystallization in ultramafic-mafic igneous complexes. The peridotites are polymetamorphic, with HP/UHP gar net-bearing assemblages being followed by a succession of retrograde assemblages related to exhu mation and cooling; some also contain evidence for a pre-HP/UHP stage, such as spinel inclusions in garnet or the presence of Ti-clinohumite. Equilibration conditions have been calculated from all available analyses of garnetiferous assemblages, by application of the olivine-garnet Fe-Mg exchange thermometer and the Al-in-orthopyroxene barometer, resulting in two distinct P-T regimes for garnet peridotites-one at high P/T in the coesite and diamond fields, and another at low P/T in the vicinity of the spinel-to-garnet transition.Garnet peridotites are thought to have evolved in at least four different tectonothermal settings, including: (1) emplacement of peridotites into oceanic or continental crust, followed by transport of peridotites and associated crust to UHP conditions by a subducting plate; (2) transfer of peridotites from a mantle wedge to the crust of an underlying, subducting plate; (3) origination from upwelling asthenosphere that passed through a high-temperature spinel peridotite stage, followed by cooling into the garnet peridotite field; and (4) extraction of garnet peridotites from ancient subcontinental lithosphere, perhaps by deep-seated faulting within a continental plate.

show abstract

Variscan migmatites, eclogites and garnet-peridotites of the Ulten zone, Eastern Austroalpine system

Cited by 75 publications

References 31 publications

Multiple partial melting events in the Ailao Shan–Red River and Gaoligong Shan complex belts, SE Tibetan Plateau: Zircon U–Pb dating of granitic leucosomes within migmatites

Multiple partial melting events in the Ailao Shan–Red River and Gaoligong Shan complex belts, SE Tibetan Plateau: Zircon U–Pb dating of granitic leucosomes within migmatites

Geochemical syntheses among the cratonic, off-cratonic and orogenic garnet peridotites and their tectonic implications

Garnet Peridotites in Eurasian High-Pressure and Ultrahigh-Pressure Terranes: A Diversity of Origins and Thermal Histories

Contact Info

Product

Resources

About