The mafic rocks preserve partially transitional relationships from protolith gabbro to UHP eclogite, as documented by detailed petrological, geochronological, and.

Trace element data suggest that the eclogite protoliths include both enriched and normal mid‐oceanic ridge basalt (E‐MORB and N‐MORB) and also gabbroic cumulates. The blueschists show more variation in protoliths, which include N‐MORB, Oceanic Island Basalt (OIB) and Island Arc Basalt (IAB).

10 th International Kimberlite Conference, Bangalore - 2012. formation at low pressures, albeit in a scenario where either. 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.

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. 2 Ga ages, which are broadly com- and orthopyroxene rich eclogite have not been studied yet. The eclogite in the Flem Gabbro from Flemsøya in the Western Gneiss Region (WGR), Norway, is exceptional due to its peculiar mineral assemblage of olivine and orthopyroxene, which were inherited from an olivine gabbro protolith [8,33].

Variation diagrams enable us identify the crystallization sequence of the plutonic protolith, itself a function of the original tectonic setting. For example, the Borehole contains a thick, eclogite-facies cumulate sequence which we can reconstruct in detail as a layered complex containing cumulate dunite and peridotite, mela-troctolite, troctolite, gabbro, ferrogabbro, ferrodiorite, quartz-diorite and tonalite.

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.

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.

This eclogite body may once have been situated 2013-07-06 Examine the sample labeled eclogite, which forms when basalt or gabbro is metamorphosed at very high pressure, such as deep in a subduction zone, 1. Note the bimodal color of this rock. What mineral are these?

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 Retrograde eclogites (ranging from unaltered eclogite to retrograde blueschist and greenschist mantling the eclogite boulders) from Ring Mountain on the Tiburon Peninsula, near San Francisco, California, were examined for whole-rock major and trace elements to assess protolith compositions and the geochemical signature of fluids associated with retrogression. The protolith of the Kaalvallei eclogites also experienced Fe enrichment and Ca depletion with increasing alteration. In addition, population A eclogites exhibit Sr and Nd isotopic compositions similar to oceanic tholeiites. tary protolith of the complex is considered to be an eastern margin of the East European platform, which was subducted beneath island arc ( Leech and Ernst, 2000 ). Protolith: Metamorphic: Facies: Eclogite: Common minerals: Omphacite Pyrope Quartz Kyanite Rutile: Eclogite in hand sample.
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Rutile, kyanite, and quartz are typically present.

Not only do they potentially record early subduction of the Indian plate beneath Asia, but they also yield important 2011-07-02 · Eclogite is also the name of one of the metamorphic facies. A metamorphic facies is a region of pressure-temperature space in which characteristic metamorphic minerals form. Most eclogite facies are eclogites– that is, they are basalts or gabbros which have experienced metamorphism at eclogite facies pressures and temperatures.
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2014-11-01

Electron microprobe analyses of representative garnets show typical prograde zoning profiles.