Thermal state, oxygen fugacity and COH fluid speciation in cratonic lithospheric mantle: New data on peridotite xenoliths from the Udachnaya kimberlite, Siberia

Goncharov, Alexey; Ionov, Dmitri A.; Doucet, Luc S.; Pokhilenko, L. N.

doi:10.1016/j.epsl.2012.09.016

Cited by 107 publications

(73 citation statements)

References 60 publications

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“…These inclusions are similar to those described by , who proposed a formational mechanism associated with a late stage rise in fO 2 conditions. Indeed, spinel grains in the Kamchatka xenoliths show an increase in Fe 3+ from core to rim, consistent with an increase in fO 2 due to exposure to late-stage, subduction-related fluids (Ionov, 2010;Goncharov et al, 2012). Such oxidizing fluids can be present at mantle depths and may explain the magnetite observed in the other xenolith suites.…”

Section: Reason 5 Ascent Of Mantle Xenoliths and Implications For Mamentioning

confidence: 62%

“…Clearly, parts of the lithospheric mantle can be cooler than the pressure-corrected Curie temperature of magnetite (<600ºC), for example, in cratonic interiors (e.g. ; Jones et al, 2003;Batumike et al, 2009;Blackwell et al, 2011;Griffin et al, 2011;Goncharov et al, 2012), subduction zones (e.g., Ernst, 1988;Liou et al, 1999;Bostock et al, 2002;Tsujimori et al, 2006), and old oceanic lithosphere (e.g., Ildefonse, 2010). The geothermal gradient in the continental crust varies greatly with the age of the crust while the geothermal gradient in the upper mantle is less variable.…”

Section: Reason 3 Temperature Of the Uppermost Mantle In Cold Geothementioning

confidence: 99%

“…Temperature distribution in the lithosphere (Figure 3) can be evaluated by i) the pressuretemperature of equilibration of mantle xenolith suites (e.g., Goncharov et al, 2012); ii) surface heat flow measurements, iii) magnetization contrasts inferred from satellite magnetic data (e.g., Manea and Manea, 2012), and iv) spectral magnetic depth determination of near-surface magnetic data. The xenolith-based approach, however does not inform about on the current geotherm present in the region of origin of the xenoliths (e.g., Kobussen et al, 2008 2005).…”

Section: Reason 3 Temperature Of the Uppermost Mantle In Cold Geothementioning

confidence: 99%

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Eight good reasons why the uppermost mantle could be magnetic

et al. 2014

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Wasilewski et al. (1979) concluded that no magnetic remanence existed in the uppermost mantle and that even if present, such sources would be at temperatures too high to contribute to long wavelength magnetic anomalies (LWMA). However, new collections of unaltered mantle xenoliths indicate that the uppermost mantle could contain ferromagnetic minerals. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 2/39This is most easily explained as a thermoremanent magnetization acquired by pre-existing ferromagnetic minerals as xenoliths cool rapidly at the Earth's surface from magmatic temperatures, acquired during ascent. 7. Modern experimental data suggest that the wüstite-magnetite oxygen buffer and the fayalite-magnetite-quartz oxygen buffer extend several tens of km within the uppermost mantle. 8. The magnetic properties of mantle xenoliths vary consistently across tectonic settings. In conclusion, the model of a uniformly non-magnetic mantle should be revisited.

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Section: Reason 5 Ascent Of Mantle Xenoliths and Implications For Mamentioning

confidence: 62%

Section: Reason 3 Temperature Of the Uppermost Mantle In Cold Geothementioning

confidence: 99%

Section: Reason 3 Temperature Of the Uppermost Mantle In Cold Geothementioning

confidence: 99%

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Eight good reasons why the uppermost mantle could be magnetic

et al. 2014

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“…When comparing with the garnet peridotites in the Kaapvaal craton, those of the Siberian craton generally have higher Mg/Si and lower Mg# (Figure 1) (e.g., Boyd et al 1997;Doucet et al 2013). The equilibrium pressure of garnet peridotite xenoliths calculated using the olivine-garnet-orthopyroxene geothermobarometer shows that Siberian garnet peridotite xenoliths were derived from up to about 7 GPa (e.g., Goncharov et al 2012;Doucet et al 2013), which is almost identical to those of southern Africa (e.g., Kawasaki 1987). Therefore, the chemical difference between the Kaapvaal craton and the Siberian craton could not be originated by a difference of the depth of melting.…”

Section: Resultsmentioning

confidence: 99%

“…Data for abyssal peridotites are after Michael and Bonatti (1985), Dick (1989), Dick and Natland (1996), Arai and Matsukage (1996), and Matsukage et al (2005). Data for the Kaapvaal and Siberian cratons are after Nixon and Boyd (1973), Cox et al (1973), Carswell et al (1979), Boyd et al (1993), Boyd et al (1997), Gibson et al (2008), Katayama et al (2009), Goncharov et al (2012, and Doucet et al (2013). CI chondrite, geochemical fractionation trend, and cosmochemical fractionation trend are referred from Jagoutz et al (1979).…”

Section: Chemical and Modal Variations Of Continental Cratonic Peridomentioning

confidence: 99%

Hydrous origin of the continental cratonic mantle

Matsukage

Kawasaki

2014

Earth, Planets and Space

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We performed melting experiments of hydrous pyrolite at pressures from 3 to 8 GPa and temperatures from 1,100°C to 1,800°C to identify the origin of chemical variation in cratonic garnet peridotites with high contents of magnesian orthopyroxene. In hydrous conditions, the stability field of residual orthopyroxene expands relative to olivine above solidus, and the harzburgitic residue contains large amounts of Mg-rich (Mg# > 0.92) orthopyroxene at 4.5 to 6 GPa. The residual chemistry obtained from our experiments indicates that the chemical variation of the cratonic garnet peridotites possibly reflects formation by melt depletion under various water contents from almost anhydrous to a maximum of approximately 1% to 2% in the upper mantle at depths of about 100 to 200 km.

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Earthquakes in the Mantle? Insights From Rock Magnetism of Pseudotachylytes

et al. 2017

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Ultramafic pseudotachylytes have been regarded as earthquake fossils formed at mantle depths (i.e., >30 km). Here we show that pseudotachylytes hosted by ultramafic rocks from three localities have distinct magnetic properties. Fresh host peridotites contain only small amounts of coarse‐grained magnetite. In contrast, the ultramafic pseudotachylytes contain variable amounts of significantly finer magnetite that formed coseismically through melting. Among each locality, magnetite abundance in the pseudotachylytes ranges over several orders of magnitude (4–2,000 ppm), and magnetic grain size varies considerably (from single domain to multidomain). Because the host peridotites are compositionally similar, the pseudotachylyte magnetic properties are interpreted to primarily reflect the physical and cooling conditions prevailing during seismic slip. Further, the examination of laboratory‐produced ultramafic pseudotachylytes shows that quenching does not produce superfine magnetite. We hypothesize that the magnetic properties of ultramafic pseudotachylytes are controlled by fO2 and in consequence vary systematically with depth of formation. Therefore, these properties can be used to assess if the ruptures producing the earthquakes that these pseudotachylytes represent nucleated at actual mantle depths or at shallow depths during exhumation of mantle rocks.

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Thermal state, oxygen fugacity and COH fluid speciation in cratonic lithospheric mantle: New data on peridotite xenoliths from the Udachnaya kimberlite, Siberia

Cited by 107 publications

References 60 publications

Eight good reasons why the uppermost mantle could be magnetic

Eight good reasons why the uppermost mantle could be magnetic

Hydrous origin of the continental cratonic mantle

Earthquakes in the Mantle? Insights From Rock Magnetism of Pseudotachylytes

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