Summary
Compositions of the hydrous melts in equilibrium with garnet, omphacitic clinopyroxene and quartz have been investigated experimentally at 28.5 and 35 kbar. They are represented by silica-rich liquids (> 70% SiO2) with low MgO, FeO and CaO contents. The removal of ca 10–15% of the magma of this composition may be sufficient to convert quartz eclogite formed after subduction of altered MORB into a quartz-free bimineralic eclogite assemblage, which is a common type of xenoliths in kimberlites.
At 28.5 kbar the solidus temperature is between 700 and 750° C in the system quartz eclogite—water, and the high pressure amphibole-out boundary lies at ca 25 kbar in accord with the previous studies.
Zusammenfassung
Um Prozesse zu simulieren, die bei der Subduktion von Ozeanbodenbasalten durch partielle Anatexis im Stabilitätsfeld von Eklogiten ablaufen, wurde die Zusammensetzung wasserhältiger Schmelzen in Gleichgewicht mit Granat, Omphacit und Quarz bei 28.5 und 35 Kbar experimentell untersucht. Diese Schmelzen sind reich an SiO2 (> 70 Gew%) und arm an Mg0, Fe0 and CaO. Die Extraktion von ca. 10–15% derartiger Schmelzen würde genügen, um quarzführende Eklogite, die durch die Subduktion von alteriertem MORB Material entstanden sind, in quarzfreie bimineralische Eklogite umzuwandeln wie sie häufig als Xenolithe in Kimberliten beobachtet werden.
Im System Quarz-Eklogit-Wasser liegt die Solidustemperatur bei 28.5 Kbar zwischen 700 und 750°C. Die obere Stabilitätsgrenze von Amphibol liegt in diesem Temperaturbereich bei ca. 25 Kbar.
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References
Green TH (1982) Anatexis of mafic crust and high pressure studies of andesites. In:Thorpe RS (ed) Andesites. Wiley, New York, pp 465–487
Green TH, Ringwood AE (1968) Genesis of the calc-alkaline igneous rock suite. Contrib Mineral Petrol 18: 105–162
Green TH, Pearson NJ (1986) Ti-rich accessory phase saturation in hydrous mafic-felsic compositions at high P, T. Chem Geol 54:185–201
Ireland TR, Rudnick RL, Spetsius Z (1994) Trace elements in diamond inclusions reveal link to Archean granites. Earth Planet Sci Lett 128: 199–213
Jenner GA, Foley SF, Jackson SE, Green TH, Fryer BJ, Longerich HP (1994) Determination of partition coefficients for trace elements in high pressure-temperature experimental run products by laser ablation microprobe-inductively coupled plasma-mass spectrometry (LAM-ICP-MS). Geochim Cosmochim Acta 58: 5099–5103
Miller Ch, Stosch H-G, Hoernes St (1988) Geochemistry and origin of eclogites from the type locality Koralpe and Saualpe, Eastern Alps, Austria. Chem Geol 67: 103–118
Mirwald PW, Getting IC, Kennedy GC (1975) Low-friction cell for piston-cylinder highpressure apparatus. J Geophys Res 80: 1519–1525
Peacock SM, Rushmer T, Thompson AB (1994) Partial melting of subducted oceanic crust. Earth Planet Sci Lett 121: 227–244
Poli S (1993) The amphibolite-eclogite transformation: an experimental study on basalt. Am J Sci 293: 1061–1107
Rapp RP, Watson EB (1995) Dehydration melting of metabasalt at 8–32 kbar: implications for continental growth and crust-mantle recycling. J Petrol 36: 891–931
Rapp RP, Watson EB, Miller CF (1991) Partial melting of amphibolite/eclogite and the origin of Archean trondjemites and tonalites. Precamb Res 51: 1–25
Ringwood AE (1990) Slab-mantle interactions. 3. Petrogenesis of interplate magmas and structure of the upper mantle. Chem Geol 82: 187–207
Rushmer T (1991) Partial melting to two amphibolites; contrasting experimental results under fluid-absent conditions. Contrib Mineral Petrol 107: 41–59
Ryerson FJ, Watson EB (1987) Rutile saturation in magmas: implications for Ti-Nb-Ta depletion in island-arc basalts. Earth Planet Sci Lett 86: 225–239
Stern CR, Wyllie PJ (1978) Phase compositions through crystallization interval in basaltandesite-H2O at 30 kbar with implications for subduction zone magmas. Am Mineral 63: 641–663
Ulmer P, Trommsdorff V (1995) Serpentine stability to mantle depths and subduction-related magmatism. Science 268: 858–861
Yasuda A, Fujii T, Kurita K (1994) Melting phase relations of an anhydrous mid-ocean ridge basalt from 3 to 20 GPa: implications for the behaviour of subducted oceanic crust in the mantle. J Geophys Res 99: 9401–9414
Yaxley GM, Green DH (1994) Experimental demonstration of refractory carbonate-bearing eclogite and siliceous melt in the subduction regime. Earth Planet Sci Lett 128: 313–325
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Ryabchikov, I.D., Miller, C. & Mirwald, P.W. Composition of hydrous melts in equilibrium with quartz eclogites. Mineralogy and Petrology 58, 101–110 (1996). https://doi.org/10.1007/BF01165766
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DOI: https://doi.org/10.1007/BF01165766