Eclogite (Muenchberg Gneiss Massif; Early Ordovician protolith, about 480 Ma; Late Devonian metamorphism, about 365 Ma; Wissenstein, just south of

4 Aug 2015 The protolith ages of the eclogites within the High-Grade Metamorphic Complex on the north side of the Posada–Asinara Line are Ordovician,

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. Reference Shchukina, Agashev and Zedgenizov 2018; note that this sample is labelled as 106/505 and G3-12 in the first and second publications on this eclogite protolith and the hostJericho kimberlite, both the secondary isochron age and the c.2·2 Ga Stacey^Kramers model age are con-sistent with Paleoproterozoic protolith oceanic crust formation.

Eclogite protolith

Liu et al. [2007] dated three The magmatic zircon from both the retrograded eclogite and mafic schist yielded protolith ages of 451 ± 3 Ma, which is consistent with the ages of Early Palaeozoic ophiolitic complexes and ocean island sequences in the CMOB reported in previous studies. 2011-07-02 The Gubaoquan eclogite occurs in the Paleozoic Beishan Orogen of NW China. Previously it has been interpreted as a fragment of subducted oceanic crust that was emplaced as a mélange within continental rocks. Contrary to this, we demonstrate that the Gubaoquan eclogite protolith was a Neoproterozoic basic dyke/sill which intruded into Proterozoic continental rocks. 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 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.

eclogite protolith and the hostJericho kimberlite, both the secondary isochron age and the c.2·2 Ga Stacey^Kramers model age are con-sistent with Paleoproterozoic protolith oceanic crust formation. Eclogite xenoliths and eclogitic diamond inclusions from the Slave craton almost exclusively yield c. 2 Ga ages, which are broadly com-

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 lithospheric mantle with possible mantle metasomatism, (5) interaction with In steady-state subduction zones with high rates of shear heating, the upper parts of the subducting oceanic crust progress through the greenschist → amphibolite → granulite → eclogite facies, whereas lower parts of the subducting oceanic crust progress through the blueschist → eclogite facies. If one adopts MORB as the protolith of eclogite it will be particularly dense because of its high SiO 2 (stishovite) content compared to other mafic protoliths, such as cumulates, restites, delaminated continental crust and the average composition of oceanic crust. Eclogite (Muenchberg Gneiss Massif; Early Ordovician protolith, about 480 Ma; Late Devonian metamorphism, about 365 Ma; Wissenstein, just south of Stammbach, Frankenwald Forest, Bavaria, southeast-central Germany) 1 (15097930745).jpg 734 × 837; 855 KB. On the contrary, both the Jericho DIs and host eclogite garnets have small negative Eu and Sr anomalies, fractionated HREE patterns ((Lu N /Gd N)~3-5) and pristine mantle-like δ 18 O values of 5.2-6.0‰, indicating that shallow, plagioclase-rich oceanic crust protoliths are unlikely.The eclogitic DI trace-element characteristics require that both garnet and plagioclase were present in the protolith, which likely crystallized in the shallow upper mantle.

If one adopts MORB as the protolith of eclogite it will be particularly dense because of its high SiO 2 (stishovite) content compared to other mafic protoliths, such as cumulates, restites, delaminated continental crust and the average composition of oceanic crust.

Norwegian Geological Survey Rock group, Metamorphic. Metamorphism type, Regional High pressure. High temperature. Metamorphic rock class, Metabasite Metapelite. Protolith Eclogite appears to be moderately common in portions of the upper mantle, but it high-grade burial metamorphism (mantle depths) of a Proterozoic protolith.

The δ18O values and the reconstructed whole-rock trace element compositions indicate an oceanic crustal protolith for mantle eclogite xenoliths. The protolith to the eclogite is believed to be a Fe- and Ti-rich gabbro of Pro-terozoic age. Transformation into eclogite is related to Cale-donian high-pressure metamorphism at ca. 400 Ma. During this process, ilmenite in the gabbro protolith was replaced by rutile. The eclogite body is subdivided into a leuco-eclogite and a ferro-eclogite Eclogite from the Devonian of Germany. (9.0 centimeters across at its widest) Eclogite is an attractive, uncommon, crystalline-textured, very high-grade metamorphic rock. It is dominated by green & red minerals.
Hickey on neck

The blueschists show more variation in protoliths, which include N‐MORB, Oceanic Island Basalt (OIB) and Island Arc Basalt (IAB). Eclogites show a dispersion of model ages from 1.95 billion years to 670 million years. On the graphs in the εNd(T)–87Sr/86Sr and εNd(T)–T coordinates, eclogites were shown to form trends that can be interpreted as a result of contamination of the eclogite protolith by the host rocks.

The green is omphacite pyroxene. Eclogite appears to be moderately common in portions of the upper mantle, but it occurs in very few places at the Earth's surface.
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av D Carlsson · 2015 — amphibolite to granulite facies conditions and eclogite facies conditions have been locality the protolith, hydrothermal fluids and intrusions can affect the

Contrary to this, we demonstrate that the Gubaoquan eclogite protolith was a Neoproterozoic basic dyke/sill which intruded into Proterozoic continental rocks. 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 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. printing (Fig. 2a). The protolith is low-K basalt in composition and exhibits geochemical characters of normal-type MORB (N-MORB) afﬁnity (Song et al. 2006).We named itbasaltic eclogite.

under eclogite-facies metamorphism and thereafter variably affected by retrograde processes. Eclogites in which represent relics of the eclogite protolith. Fig.

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. Reference Shchukina, Agashev and Zedgenizov 2018; note that this sample is labelled as 106/505 and G3-12 in the first and second publications on this eclogite protolith and the hostJericho kimberlite, both the secondary isochron age and the c.2·2 Ga Stacey^Kramers model age are con-sistent with Paleoproterozoic protolith oceanic crust formation. Eclogite xenoliths and eclogitic diamond inclusions from the Slave craton almost exclusively yield c.

Most eclogite facies are eclogites– that is, they are basalts or gabbros which have experienced metamorphism at eclogite facies pressures and temperatures. The internal structures of zircons in eclogite from Huangzhen have been studied by cathodoluminescence (CL) microscopy.