Role of ‘hidden’ deeply subducted slabs in mantle depletion

Kamber, Balz S.; Collerson, K. D.

doi:10.1016/s0009-2541(99)00218-1

Cited by 130 publications

(52 citation statements)

References 79 publications

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“…[49] We note that the excess Nb in the calculated spidergrams might be attributed to a subducted slab component, as subducted slabs may comprise a Nb-rich reservoir in the mantle [e.g., McDonough, 1991;Rudnick et al, 2000;Kamber and Collerson, 2000]. Alternatively, Nb may be concentrated in the core such that it does not contribute to BSE [Wade and Wood, 2001].…”

Section: Geodynamic Implications For Amentioning

confidence: 99%

Major and trace element composition of the high ³He/⁴He mantle: Implications for the composition of a nonchonditic Earth

Jackson

Jellinek

2013

Geochem Geophys Geosyst

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[1] The bulk composition of the silicate portion of the Earth (BSE) has long been assumed to be tied to chondrites, in which refractory, lithophile elements like Sm and Nd exist in chondritic relative abundances. However, the Nd from 0.51263 (chondritic) to 0.51300. The new BSE composition is depleted in highly incompatible elements, including K, relative to the chondrite-based BSE, and offers a solution the ''missing '' 40 Ar paradox. This BSE compositional model requires that >83% of the mantle is depleted to form continental crust. It also implies a $30% reduction in BSE U, Th and K, and therefore in the current rate of radiogenic heating and, thus, a proportional increase in the heat flow delivered to surface by plate tectonics. We explore thermal history models including effects related to a newly recognized evolution in the style of plate tectonics over Earth history: The lower radiogenic heat production may delay the onset of core convection and dynamo action to as late as 3.5 Gyr.

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Section: Geodynamic Implications For Amentioning

confidence: 99%

Major and trace element composition of the high ³He/⁴He mantle: Implications for the composition of a nonchonditic Earth

Jackson

Jellinek

2013

Geochem Geophys Geosyst

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“…The subchondritic Nb/Ta ratio of continental crust (ca. 12) is another feature that Kamber and Collerson (2000) have attributed to preferential Ta advection from dehydrating slab into the mantle wedge. As recently demonstrated by Kamber et al (2002), direct slab-melts (i.e.…”

Section: Geochemical Signature Of Slab-derived Fluids In All Archaeanmentioning

confidence: 99%

Importance of water for Archaean granitoid petrology: a comparative study of TTG and potassic granitoids from Barberton Mountain Land, South Africa

Kleinhanns

Kramers

Kamber

2003

Contributions to Mineralogy and Petrology

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A new model for Archaean granitoid magmatism is presented which reconciles the most important geochemical similarities and differences between tonalite-trondhjemite-granodiorite (TTG) and potassic granitoids. Trace element abundances reveal a strong arc magmatism signature in all studied granitoids from Barberton Mountain Land. Characteristic features include HFSE depletion as well as distinct enrichment peaks of fluid-sensitive trace elements such as Pb in N-MORB normalisation, clearly indicating that all studied granitoids are derived from refertilised mantle above subduction zones. We envisage hydrous basaltic (s.l.) melts as parental liquids, which underwent extensive fractional crystallisation. Distinctive residual cumulates evolved depending on initial water content. High-H 2 O melts crystallised garnet/amphibole together with pyroxenes and minor plagioclase, but no olivine. This fractionation path ultimately led to TTG-like melts. Less hydrous basaltic melts also crystallised garnet/ amphibole, but the lower compatible element content indicates that olivine was also a liquidus phase. Pronounced negative Eu-anomalies of the granitic melts, correlating with Na, Ca and Al, indicate plagioclase to be of major importance. In the context of our model, the post-Archaean disappearance of TTG and concomitant preponderance of granites (s.l.), therefore, is explained with secular decrease of aqueous fluid transport into subduction zones and/or efficiency of deep fluid release from slabs.

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“…3, 5, 6). In addition, the Nb/Ta values for the BVR trachytes (14.4-16.0) are intermediate between those of mantle-derived melts (17.5 ± 2.0) (Green, 1995;Kamber and Collerson, 2000) and the average continental crust (11-12) (Rudnick and Gao, 2003), which also implies that mixing occurred between crust-and mantle-derived magmas.…”

Section: Petrogenesis Of the Bvr Trachytesmentioning

confidence: 94%

“…5a). In addition, the results of melting experiments of anhydrous lherzolite show that the silica content of low-degree partial melts is b~55 wt.% (andesite) (Baker et al, 1995 Sr (t) ratios (0.709362-0.711522), and low ε Nd(t) values (− 7.6 to − 9.8) ( Table 2), coupled with low Nb/Ta ratios (16.0-14.4) compared with mantle-derived melts (17.5 ± 2.0) (Green, 1995;Kamber and Collerson, 2000). These characteristics suggest they were not directly generated by partial melting of a typical mantle rock.…”

Section: Petrogenesis Of the Bvr Trachytesmentioning

confidence: 99%

Geochemistry of Miocene trachytes in Bugasi, Lhasa block, Tibetan Plateau: Mixing products between mantle- and crust-derived melts?

Chen

Zhao

et al. 2012

Gondwana Research

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Role of ‘hidden’ deeply subducted slabs in mantle depletion

Cited by 130 publications

References 79 publications

Major and trace element composition of the high ³He/⁴He mantle: Implications for the composition of a nonchonditic Earth

Major and trace element composition of the high ³He/⁴He mantle: Implications for the composition of a nonchonditic Earth

Importance of water for Archaean granitoid petrology: a comparative study of TTG and potassic granitoids from Barberton Mountain Land, South Africa

Geochemistry of Miocene trachytes in Bugasi, Lhasa block, Tibetan Plateau: Mixing products between mantle- and crust-derived melts?

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Role of ‘hidden’ deeply subducted slabs in mantle depletion

Cited by 130 publications

References 79 publications

Major and trace element composition of the high 3He/4He mantle: Implications for the composition of a nonchonditic Earth

Major and trace element composition of the high 3He/4He mantle: Implications for the composition of a nonchonditic Earth

Importance of water for Archaean granitoid petrology: a comparative study of TTG and potassic granitoids from Barberton Mountain Land, South Africa

Geochemistry of Miocene trachytes in Bugasi, Lhasa block, Tibetan Plateau: Mixing products between mantle- and crust-derived melts?

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Major and trace element composition of the high ³He/⁴He mantle: Implications for the composition of a nonchonditic Earth

Major and trace element composition of the high ³He/⁴He mantle: Implications for the composition of a nonchonditic Earth