Trace element fractionation during fluid-induced eclogitization in a subducting slab: trace element and Lu–Hf–Sm–Nd isotope systematics

John, Timm; Scherer, Erik E.; Haase, Karsten M.; Schenk, Volker

doi:10.1016/j.epsl.2004.09.009

Cited by 213 publications

(153 citation statements)

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“…We used the average compositions of Zambezi Belt group I and II eclogites reported in John et al (2004), a good estimate for average recycled oceanic lithosphere (Pfänder et al 2007), as the compositions of the recycled oceanic crust. We used the moderate incompatible element ratios (Zr/Hf, Lu/Hf and Dy/Yb) to estimate the degrees of pyroxenite melting (Stracke and Bourdon 2009).…”

Section: Discussionmentioning

confidence: 99%

“…The compositions of pyroxenite source are from the average compositions of Zambezi Belt group I and II eclogite (John et al 2004). Melt fraction is displayed as percent along the melting curves H 2 O content in the source of Xindian basalts Previous studies on peridotite xenoliths in the NCC showed that H 2 O contents of these peridotites were generally lower than those of peridotites in other Archaean cratons, and Proterozoic or younger-age off-cratons, and abyssal peridotites Xia et al 2010).…”

Section: Discussionmentioning

confidence: 99%

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Constraints from melt inclusions and their host olivines on the petrogenesis of Oligocene-Early Miocene Xindian basalts, Chifeng area, North China Craton

Zhang

Qian

et al. 2012

Contrib Mineral Petrol

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The geochemical characteristics of melt inclusions and their host olivines provide important information on the processes that create magmas and the nature of their mantle and crustal source regions. We report chemical compositions of melt inclusions, their host olivines and bulk rocks of Xindian basalts in Chifeng area, North China Craton. Compositions of both bulk rocks and melt inclusions are tholeiitic. Based on petrographic observations and compositional variation of melt inclusions, the crystallizing sequence of Xindian basalts is as follows: olivine (at MgO [ *5.5 wt%), plagioclase (beginning at MgO = *5.5 wt%), clinopyroxene and ilmenite (at MgO \ 5.0 wt%). High Ni contents and Fe/Mn ratios, and low Ca and Mn contents in olivine phenocrysts, combining with low CaO contents of relatively high MgO melt inclusions (MgO [ 6 wt%), indicate that Xindian basalts are possibly derived from a pyroxenite source rather than a peridotite source. In the CS-MS-A diagram, all the high MgO melt inclusions (MgO [ 6.0 wt%) project in the field between garnet ? clinopyroxene ? liquid and garnet ? clinopyroxene ? orthopyroxene ? liquid near 3.0 GPa, further suggesting that residual minerals are mainly garnet and clinopyroxene, with possible presence of orthopyroxene, but without olivine. Modeling calculations using MELTS show that the water content of Xindian basalts is 0.3-0.7 wt% at MgO = 8.13 wt%. Using 20-25 % of partial melting estimated by moderately incompatible element ratios, the water content in the source of Xindian basalts is inferred to be C450 ppm, much higher than 6-85 ppm in dry lithospheric mantle. The melting depth is inferred to be *3.0 GPa, much deeper than that of tholeiitic lavas (\2.0 GPa), assuming a peridotite source with a normal mantle potential temperature. Such melting depth is virtually equal to the thickness of lithosphere beneath Chifeng area (*100 km), suggesting that Xindian basalts are derived from the asthenospheric mantle, if the lithospheric lid effect model is assumed.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Constraints from melt inclusions and their host olivines on the petrogenesis of Oligocene-Early Miocene Xindian basalts, Chifeng area, North China Craton

Zhang

Qian

et al. 2012

Contrib Mineral Petrol

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“…7a), where Dy is used as an element with an incompatibility similar to Li (Ryan and Langmuir, 1987) to eliminate effects of magmatic processes such as fractional crystallization, and Hf/Yb is used as a proxy for mantle source characteristics (John et al, 2004). There is a clear Li enrichment compared to fresh MORB, and many of the MORB-type eclogites have Li/Dy ratios significantly higher than typical AOC as well.…”

Section: Morb-type Eclogites: Internal LI Metasomatism At Hp Conditionsmentioning

confidence: 99%

“…The direct examination of subduction zone metamorphic rocks provides insight of how mass is redistributed during metamorphism (e.g., Bebout, 1991;Beinlich et al, 2010;Gao et al, 2007;John et al, 2008;King et al, 2004;Sorensen and Grossman, 1989;Spandler et al, 2003Spandler et al, , 2004, about the nature of slab-derived agents added to arc lava sources and about chemical changes in subducting rocks potentially contributing to the geochemical heterogeneity of the upper mantle (e.g., Bebout, 2007;Breeding et al, 2004, John et al, 2004. Increasing attention has been directed towards metasomatic processes within subducted rocks because metasomatic rocks can constitute new bulk compositions that can influence the redistribution of major and trace elements (Bebout, 2007;King et al, 2006King et al, , 2007Scambelluri et al, 2006;Zack and John, 2007).…”

Section: Introductionmentioning

confidence: 99%

A stable (Li, O) and radiogenic (Sr, Nd) isotope perspective on metasomatic processes in a subducting slab

et al. 2011

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Two distinct types of eclogites from the Raspas Complex (Ecuador), which can be distinguished based on petrography and trace element geochemistry, were analyzed for their stable (Li, O) and radiogenic (Sr, Nd) isotope signature to constrain metasomatic changes due to fluid-overprinting in metabasaltic rocks at high-pressure conditions and to identify fluid sources. MORB-type eclogites are characterized by a relative LREE depletion similar to MORB. High-pressure (HP) minerals from this type of eclogite have highly variable oxygen isotope compositions (garnet: +4.1 to +9.

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“…Nevertheless, the rare occurrence of primary amphibole in the xenoliths reported by previous authors (Xu et al 2006a(Xu et al , 2009a would suggest that only a very small amount of water was present. In fact, the lowercrustal rocks are usually at granulite facies, which may be transformed into eclogite facies through addition of fluids under appropriate P-T conditions (John et al 2004). Addition of water from a subducted oceanic slab (Niu 2005) may have contributed to the eclogitization and subsequent partial melting of the NCC lower continental crust.…”

Section: Slab Melting Versus Lower Continental Crust Meltingmentioning

confidence: 99%

Destruction of the North China Craton Induced by Ridge Subductions

Ling

Li²,

Ding

et al. 2013

The Journal of Geology

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A B S T R A C TThe destruction of the North China Craton (NCC) mainly occurred in the Cretaceous and has been attributed to a "top-down" rapid delamination, "bottom-up" long-term thermal/chemical erosions, or hydration by subductionreleased fluids. On the basis of the distribution of one Jurassic and two Early Cretaceous adakite belts and the drifting history of the paleo-Pacific Plate, we propose that three ridge subduction events dominated the large-scale decratonization in the NCC. Both physical erosion and magmatism induced by ridge subduction contributed to the destruction of the NCC; the last ridge subduction, at Ma, was the key driving force in the final destruction. We present 130 ‫ע‬ 5 mineralogical, geochemical, and isotopic data in support of the ridge subduction model: flat subduction of a spreading ridge resulted in stronger physical erosion on the thick lithosphere mantle of the NCC. Consequently, slab melting occurred during ridge subduction, forming adakites with mantle Mg isotope compositions, followed by A-type granites as a result of asthenosphere upwelling. Delaminated lower continental crust was also partially melted after reacting with hydrous magmas, as indicated by eclogite xenoliths, resulting in a zircon age spectrum similar to that of the NCC and some adakitic samples with chemical characteristics similar to those of the Dabie adakites. The final decratonization was triggered by the last ridge subduction, with both physical erosion (flat subduction) and thermal erosion (adakitic and A-type magmatisms). Given that ridge subduction has occurred throughout Earth's history, the associated decratonization processes are presumably a common phenomenon that modified the chemical compositions of the continental crust.

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Trace element fractionation during fluid-induced eclogitization in a subducting slab: trace element and Lu–Hf–Sm–Nd isotope systematics

Cited by 213 publications

References 50 publications

Constraints from melt inclusions and their host olivines on the petrogenesis of Oligocene-Early Miocene Xindian basalts, Chifeng area, North China Craton

Constraints from melt inclusions and their host olivines on the petrogenesis of Oligocene-Early Miocene Xindian basalts, Chifeng area, North China Craton

A stable (Li, O) and radiogenic (Sr, Nd) isotope perspective on metasomatic processes in a subducting slab

Destruction of the North China Craton Induced by Ridge Subductions

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