Subduction-related eclogites are products of their igneous, metamorphic, fluid-rock, and tectonic histories. Changes of bulk rock chemistry, mineral assemblages and compositions, as well as microstructures operate in concert both before and during subduction to transmogrify ocean floor basalt into subduction zone eclogite. We present textural and chemical characterizations of suites of

Major element contents of the eclogite cores are broadly similar to basalts with the exception of the high Na contents, presumably reflecting a seawater-altered oceanic crust protolith (Fig. 2).

Kaalvallei Group II eclogite xenoliths are likely to have formed through crystallization of small-volume melts within conduits in old, enriched subcontinental lithosphere. Geochemistry of eclogite- and blueschist-facies rocks from the bantimala complex, south sulawesi, indonesia: Protolith origin and tectonic setting Citation Maulana, A, Christy, A, IMAI, A et al 2013, 'Geochemistry of eclogite- and blueschist-facies rocks from the bantimala complex, south sulawesi, indonesia: Protolith origin and tectonic setting', The Island Arc, vol. 22, no. 4, pp. 427-452.

The kyanite–eclogite is derived from a troctolitic protolith, whereas the epidote–eclogite from a gabbroic protolith, both having distinct positive Eu anomalies, low TiO 2, and high Al 2O 3 and MgO. The kyanite–eclogite shows inherited cumulate layering. The phengite–eclogite has high TiO 2, low Al 2O 3 and MgO with incompatible trace eclogite Sm–Nd/WR igneous formation of eclogite protolith Stosch & Lugmair (1990) Weissenstein (SW MM) 395–380 Ma eclogite Sm–Nd; Rb–Sr eclogite metamorphism Stosch & Lugmair (1990) Weissenstein area 379 ± 12 Ma eclogite Rb–Sr/Hbl, phengite post-eclogite Gebauer & Grünenfelder (1979) K–Ar Hangendserie Eclogite-rich layers would be intermittent because of low melting points and the temperature-dependency of the relevant phase changes. and the composition of the lower mantle. If one adopts MORB as the protolith of eclogite it will be particularly dense because of its high SiO 2 (stishovite) EVOLUTION OF ECLOGITE FACIES METAMORPHISM IN THE ST. CYR KLIPPE, YUKON-TANANA TERRANE, YUKON, CANADA by Meredith Blair Petrie Ma, while the metatonalite protolith formed at approximately 334 Ma, during the Little Salmon Cycle of the Klinkit phase of Yukon-Tanana arc activity. Geochemistry of eclogite- and blueschist-facies rocks from the Bantimala Complex, South Sulawesi, Indonesia: Protolith origin and tectonic setting December 2013 Island Arc 22(4) Geochemistry of eclogite- and blueschist-facies rocks from the Bantimala Complex, South Sulawesi, Indonesia: Protolith origin and tectonic setting ADI MAULANA,1,2,3*ANDREW G. CHRISTY,1,4 DAVID J. ELLIS,1 AKIRA IMAI,5 AND KOICHIRO WATANABE3 1Research School of Earth Sciences, Australian National University, Canberra ACT 0200, Australia, 2Department The variability of δ18O in garnet among 41 xenoliths, shows a bi-modal distribution with median values at 3.57 ‰ and 5.68 ‰ and strong correlation (r = 0.96) between garnet and omphacite. The δ18O values and the reconstructed whole-rock trace element compositions indicate an oceanic crustal protolith for mantle eclogite xenoliths.

Geochemical signatures for eclogite protolith from the Maksyutov Complex, South Urals N.I. Volkova*, A.E. Frenkel, V.I. Budanov, G.G. Lepezin Institute of Mineralogy

Reference Korolev, Melnik, Li and Skublov 2018): (1) formation of an oceanic crust protolith (i.e. basalts and gabbros), (2) hydrothermal alteration of the oceanic crust by seawater, (3) subduction-related metamorphism, partial melting and metasomatism, (4) long-term residence in the … ECLOGITE . Eclogite is an attractive, uncommon, crystalline-textured, very high-grade metamorphic rock.

av O Paulsson · 1996 · Citerat av 1 — The metamorphic grade of the complex is generally amphibolite, locally eclogite facies. The protolith of the underlying Särv Nappes of the

Each aluminum oversaturation in the eclogite protolith, which can not be incorporated in garnet and omphacite, crystallized in the eclogite as kyanite (nesosilicate). The protolith rock was subjected to eclogite-facies metamorphism at 2.7 to 2.8 billion years ago, during the early Neoarchean. Uplift and decompression resulted in the formation of some new minerals, which occurred at 1.89 billion years (late Paleoproterozoic). Specimen owned by James Cheshire. (a) Zircon grains from mantle eclogite xenolith sample 106/505 (G3-12) from the V. Grib kimberlites, Arkhangelsk province (modified after Skublov et al. Reference Skublov, Shchukina, Guseva, Mal’kovets and Golovin 2011 and Shchukina et al.

How could you … Eclogite genesis might have been by residue formation associated with the dehydration and partial melting of a protolith consisting of variably mixed, subducted ocean floor basalt and sediment. Kaalvallei Group II eclogite xenoliths are likely to have formed through crystallization of small-volume melts within conduits in old, enriched subcontinental lithosphere.
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For oceanic crust containing 1-2 wt% H 2 O, dehydration will not begin until the onset of eclogite- or amphibolite-facies metamorphism, depending on the P-T path. For many subduction zones, the most important dehydration reactions in the subducting oceanic crust occur at the blueschist → eclogite facies transition associated with the The original rock that has undergone metamorphism is called the protolith. Protolith can be any type of rock and sometimes the changes in texture and mineralogy are so dramatic that is difficult to distinguish what the protolith was. Note that diagenesis and weathering are also a changes in form that occur in rocks. A metamorphic facies is a set of mineral assemblages in metamorphic rocks formed under similar pressures and temperatures.

coronitic eclogite (lower) to eclogite mylonite (upper). The corona textures are gradually destroyed as the strong, planar, mylonitic fabric developed (Loc. 1.3).
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405. Zircon U–Pb age, Hf and O isotope constraints on protolith origin of ultrahigh-pressure eclogite and gneiss in the Dabie orogen · YF Zheng, ZF Zhao, YB Wu

Eclogite contains no plagioclase although its protolith is full of this mineral. The protoliths of eclogites are igneous rocks with a basaltic composition (basalt, diabase , gabbro ). The lack of relatively light-weight plagioclase is the reason why it is so dense compared to its protoliths. The eclogite unit occurs in the LHS below the MCT, and the protolith is considered to be 110–88-Ma-old (cretaceous volcanics in the LHS).