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MORB-type

Figure 13. Model curves for continuous fluid addition to a MORB-type mantle source in (a) a °Th-isochron diagram, and (b) a ( Ra/ °Th) versus diagram. The time constant for... Figure 13. Model curves for continuous fluid addition to a MORB-type mantle source in (a) a °Th-isochron diagram, and (b) a ( Ra/ °Th) versus diagram. The time constant for...
Petrological and geochemical variations along the arc are considered to result from variable relative amounts of slab-released fluids and melts added to the mantle wedge, as well as from higher amounts of subducted sediments added to the mantle beneath eastern islands. Variation of pre-metasomatic mantle composition, from MORB-type in the central arc to OIB-type in the external islands, is also considered as an important factor for compositional diversity along the arc. [Pg.210]

MORB-type DSDP Site 373 7.3 to 4.1 - Basaltic lavas forming the... [Pg.273]

Rock type MORB-type basalt MORB-type basalt OIB-type basalt OIB-type basalt Mugearite Lamproite... [Pg.288]

Nakai S, Wakita H, Nuccio M, Italiano F (1997) MORB-type neon in an enriched mantle beneath Etna, Sicily. Earth Planet Sci Lett 153 57-66 Nappi G, Renzulli A, Santi P (1987) An evolutionary model for the Paleo-Bolsena and Bolsena Volcanic Complexes a structural and petrographic study. Per Mineral 56 241-267... [Pg.348]

Nd-Sr isotopic studies in orogenic peridotites have emphasized their wide isotopic heterogeneity but also showed that the predominant fertile Uierzolite facies are actually fairly homogenous and characterized by depleted, MORB-type isotopic compositions. The low-alumina, deformed (olivine) websterites, that are chemically equilibrated with the peridotites (see Section 2.04.4.2.3), also show a limited range of isotopic variations and are generally indistinguishable... [Pg.854]

Rampone E., Hofmann A. W., Piccardo G. B., Vannucci R., Bottazzi P., and Ottolini L. (1996) Trace element and isotope geochemistry of depleted peridotites from an N-MORB type ophiolite (Internal Liguride N. Italy). Contrib. Mineral. Petrol. 123, 61-76. [Pg.869]

Stosch H. G. and Lugmair G. W. (1990) Geochemistry and evolution of MORB-type eclogites from the Miinchberg... [Pg.1580]

Nakai S, Wakita H, Nuccio MP, Italiano F (1997) MORB-type neon in an enriched mantle beneath Etna, Sicily. Earth Planet Sci Lett 153 57-66... [Pg.366]

Therefore, it appears that He from an asthenospheric HIMU source can completely account for the He in the xenoliths, and there are no significant contributions from the lithosphere. The range in compositions can accommodate some MORB-type He from the surrounding convecting mantle or trapped earlier in the lithosphere. While Ne isotope compositions in the xenoliths were found to overlap MORB compositions, those in other HIMU basalts are not known and may also resemble MORB values, and so this may not have any diagnostic virtues. [Pg.391]

Figure 14. Neon three-isotope diagram ( Ne/ °Ne vs. Ne/ °Ne) showing the compositions and trends of various Ne components. Mixtures of atmospheric and cosmogenic Ne plot on the spallation line, the slope of which has been experimentally determined for quartz and pyroxene (Table 8). Contributions from nucleogenic Ne and Ne are characterized by shifts in horizontal and vertical directions, respectively. The trends for crustal Ne (Kennedy et al. 1990) and MORB-type Ne (Sarda et al. 1988) are also given. The dotted line labeled mfl is the mass fractionation line. Figure 14. Neon three-isotope diagram ( Ne/ °Ne vs. Ne/ °Ne) showing the compositions and trends of various Ne components. Mixtures of atmospheric and cosmogenic Ne plot on the spallation line, the slope of which has been experimentally determined for quartz and pyroxene (Table 8). Contributions from nucleogenic Ne and Ne are characterized by shifts in horizontal and vertical directions, respectively. The trends for crustal Ne (Kennedy et al. 1990) and MORB-type Ne (Sarda et al. 1988) are also given. The dotted line labeled mfl is the mass fractionation line.
Layer 2 MORB-type basalt and intrusive equivalents with intercalated sediment lenses that varies in thickness, but on average is 2.5 km. [Pg.12]

Layer 3 MORB-type basalt and intrusive equivalents of up to about 4.5 km in thickness. [Pg.12]

See other pages where MORB-type is mentioned: [Pg.264]    [Pg.102]    [Pg.164]    [Pg.207]    [Pg.273]    [Pg.281]    [Pg.282]    [Pg.286]    [Pg.164]    [Pg.169]    [Pg.815]    [Pg.989]    [Pg.113]    [Pg.288]    [Pg.8]    [Pg.292]    [Pg.328]    [Pg.338]    [Pg.765]    [Pg.258]   
See also in sourсe #XX -- [ Pg.164 ]



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E-type MORB

MORB

N-type MORB

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