On the significance of argon release from biotite and amphibole during 40Ar/39Ar vacuum heating

Gaber, Lawrence J.; Foland, K. A.; Corbató, Charles E.

doi:10.1016/0016-7037(88)90304-3

Cited by 119 publications

(51 citation statements)

References 18 publications

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“…Gaber et al, 1988): significant release starts around 800 °C and peaks at 900 -1000 °C (Fig 2). Whole rock samples without mica show release patterns similar to that of the refractory minerals (Fig 1), as expected.…”

Section: Release Patterns and Concentrations Of Nmentioning

confidence: 98%

Nitrogen in peridotite xenoliths: Lithophile behavior and magmatic isotope fractionation

Yokochi

Marty

Chazot

et al. 2009

Geochimica et Cosmochimica Acta

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International audienceIn order to document the origin and speciation of nitrogen in mantle-derived rocks and minerals, the N and Ar contents and isotopic compositions were investigated for hydrous and anhydrous peridotite xenoliths from Ataq, Yemen, from Eifel, Germany, and from Massif Central, France. Nitrogen and Ar were extracted by stepwise combustion with a fine temperature resolution, followed by fusion in a platinum crucible. A large isotopic disequilibrium of up to 25.4‰ is observed within single peridotite xenoliths, with δ15N values as low as −17.3‰ in phlogopite whereas clinopyroxene and olivine show positive δ15N values. Identical Sr isotopic ratios of phlogopite, clinopyroxene and whole rock in this wehrlite sample are consistent with crystallization from a common reservoir, suggesting that the light N signature of phlogopite might be the result of isotopic fractionation during N uptake from the host magma. The nitrogen concentration is systematically high in phlogopite, (7.6–25.7 ppm), whereas that of bulk peridotite xenoliths is between 0.1 and 0.8 ppm. The high N content of phlogopite is at least partly due to host magma–mineral interaction, and may also suggest the occurrence of N as View the MathML source that substituted for K+ during mineral growth in mafic magmas. Such speciation is consistent with the fact that N and Rb contents correlate well for a set of samples from mantle regions that were affected by subduction-related metasomatism and magmatism. The N/Rb ratios of these samples are comparable with values estimated for subduction zone magmas, but are one order of magnitude lower than the N/Rb ratios characterizing subducting slabs. This difference suggests preferential release of N relative to alkalis in the forearc region. N/40Ar* ratios of minerals from analyzed mantle xenoliths are much higher than those of vesicles in MORBs and OIBs, requiring either the occurrence of nitrogen speciation in the mantle more compatible than Ar, significant loss of fluid phase during entrainment, or long residence time of volatile elements in the mantle source(s) of fluids to increase drastically the 40Ar* budget of the latter

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Section: Release Patterns and Concentrations Of Nmentioning

confidence: 98%

Nitrogen in peridotite xenoliths: Lithophile behavior and magmatic isotope fractionation

Yokochi

Marty

Chazot

et al. 2009

Geochimica et Cosmochimica Acta

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“…350°C (McDougall and Harrison, 1988). However, it is possible that the fiat spectra could be due to the homogenization of Ar isotopes as a result of dehydrogenation during heating under vacuum (e.g., Gaber et al, 1988). This is probably not the dominant cause for two reasons; firstly, muscovite appears to be relatively stable under vacuum (Wijbrans and McDougall, 1986) compared to biotite; and secondly, an analytical artifact might be expected to affect all samples (cf.…”

Section: Late-triassic To Cretaceous Cooling Historymentioning

confidence: 99%

Differential exhumation in response to episodic thrusting along the eastern margin of the Tibetan Plateau

et al. 1997

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“…Age spectra from biotite have been shown to be a potentially unreliable means to evaluate Ar concentration gradients because of instability during heating in vacuo (Gaber et al 1988). However, biotite 40 Ar/…”

mentioning

confidence: 99%

“…Biotite is a hydrous mineral that is unstable during in vacuo laser heating (Gaber et al 1988), and thus may not produce geologically meaningful release patterns that reflect spatial Ar isotopic gradients (e.g. Brownlee & Renne 2010).…”

mentioning

confidence: 99%

Persistent long-term ( c. 24 Ma) exhumation in the Eastern Alaska Range constrained by stacked thermochronology

Benowitz

Layer

VanLaningham

2013

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On the significance of argon release from biotite and amphibole during 40Ar/39Ar vacuum heating

Cited by 119 publications

References 18 publications

Nitrogen in peridotite xenoliths: Lithophile behavior and magmatic isotope fractionation

Nitrogen in peridotite xenoliths: Lithophile behavior and magmatic isotope fractionation

Differential exhumation in response to episodic thrusting along the eastern margin of the Tibetan Plateau

Persistent long-term ( c. 24 Ma) exhumation in the Eastern Alaska Range constrained by stacked thermochronology

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