The petrology of high pressure xenoliths and associated Cenozoic basalts from Northeastern Tasmania

Nasir, Sobhi; Everard, John L.; McClenaghan, M.P.; Bombardieri, Daniel; Worthing, M. A.

doi:10.1016/j.lithos.2010.03.012

Cited by 10 publications

(3 citation statements)

References 63 publications

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“…Some groups adopted the Wood and Virgo (1989) approach (e.g., Ionov and Wood 1992;Woodland et al 1992;Luhr and Aranda-Gómez 1997;Parkinson and Pearce 1998;Parkinson and Arculus 1999;Bryant et al 2007;Wang et al 2007Wang et al , 2008Dare et al 2009), while others presented data with no correction (e.g., Ballhaus 1993;Qi et al 1995;Fedortchouk et al 2005;Canil et al 2006;Foley et al 2006;Nasir et al 2010;Wang et al 2012). Ballhaus et al (1991) questioned whether Fe 3+ /ΣFe ratios determined from EPMA require correction, and additionally suggested that such a correction may introduce additional error.…”

Section: Accuracy and Precision Of The Correction Methodsmentioning

confidence: 99%

Revisiting the electron microprobe method of spinel-olivine-orthopyroxene oxybarometry applied to spinel peridotitesk

Davis

Cottrell

Birner

et al. 2017

American Mineralogist

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Natural peridotite samples containing olivine, orthopyroxene, and spinel can be used to assess the oxygen fugacity ( f O 2 ) of the upper mantle. The calculation requires accurate and precise quantification of spinel Fe 3+ /SFe ratios. Wood and Virgo (1989) /ΣFe ratios depends on the total concentration of Fe, and varies from ±0.012 to ±0.032 (1σ) in the samples analyzed; precision of uncorrected analyses is poorer by approximately a factor of two. We also present an examination of the uncertainties in the calculation contributed by the other variables used to derive f O2 . Because there is a logarithmic relationship between the activity of magnetite and logf O2 , the uncertainty in f O2 relative to the QFM buffer contributed by the electron microprobe analysis of spinel is asymmetrical and larger at low ferric Fe concentrations (+0.3/-0.4 log units, 1σ, at Fe 3+ /ΣFe = 0.10) than at higher ferric Fe concentrations (±0.1 log units, 1σ, at Fe 3+ /ΣFe = 0.40). Electron microprobe analysis of olivine and orthopyroxene together contribute another ±0.1 to ±0.2 log units of uncertainty (1σ). Uncertainty in the temperature and pressure of equilibration introduce additional errors on the order of tenths of log units to the calculation of relative f O2 . We also document and correct errors that appear in the literature when formulating f O2 that, combined, could yield errors in absolute f O2 of greater than 0.75 log units-even with perfectly accurate Fe 3+ /ΣFe ratios. Finally, we propose a strategy for calculating the activity of magnetite in spinel that preserves information gained during analysis about the ferric iron content of the spinel. This study demonstrates the superior accuracy and precision of corrected EPMA measurements of spinel Fe 3+ /ΣFe ratios compared to uncorrected measurements. It also provides an objective method for quantifying uncertainties in the calculation of f O2 from spinel peridotite mineral compositions.

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Section: Accuracy and Precision Of The Correction Methodsmentioning

confidence: 99%

Revisiting the electron microprobe method of spinel-olivine-orthopyroxene oxybarometry applied to spinel peridotitesk

Davis

Cottrell

Birner

et al. 2017

American Mineralogist

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“…Tasmania 8-69.9 289 Adam (1990); Brown and Forsyth (1984); Brown et al (1989); Corbett et al (2014); Crawford et al (1997); Everard (1989); Everard et al (1997); Ewart et al (1988); Knutson (n.d.); McClenaghan et al (1982); McGee (2005); Nasir et al (2010); Sutherland et al (1984Sutherland et al ( , 1989; Sutherland (1989aSutherland ( , 1989b; Sutherland et al (1996); Sutherland (2004); Sutherland et al (2006).…”

Section: Ovp (O)mentioning

confidence: 99%

Thermal Structure of Eastern Australia's Upper Mantle and Its Relationship to Cenozoic Volcanic Activity and Dynamic Topography

Ball

Czarnota

White

et al. 2021

Geochem Geophys Geosyst

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Spatio‐temporal changes of upper mantle structure play a significant role in generating and maintaining surface topography. Although geophysical models of upper mantle structure have become increasingly refined, there is a paucity of geologic constraints with respect to its present‐day state and temporal evolution. Cenozoic intraplate volcanic rocks that crop out across eastern Australia provide a significant opportunity to quantify mantle conditions at the time of emplacement and to independently validate geophysical estimates. This volcanic activity is divided into two categories: age‐progressive provinces that are generated by the sub‐plate passage of mantle plumes and age‐independent provinces that could be generated by convective upwelling at lithospheric steps. In this study, we acquired and analyzed 78 samples from both types of provinces across Queensland. These samples were incorporated into a comprehensive database of Australian Cenozoic volcanism assembled from legacy analyses. We use geochemical modeling techniques to estimate mantle temperature and lithospheric thickness beneath each province. Our results suggest that melting occurred at depths ≤80 km across eastern Australia. Prior to, or coincident with, onset of volcanism, lithospheric thinning as well as dynamic support from shallow convective processes could have triggered uplift of the Eastern Highlands. Mantle temperatures are inferred to be ∼50–100°C hotter beneath age‐progressive provinces that demarcate passage of the Cosgrove mantle plume than beneath age‐independent provinces. Even though this plume initiated as one of the hottest recorded during Cenozoic times, it appears to have thermally waned with time. These results are consistent with xenolith thermobarometric and geophysical studies.

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“…Arguments for a lithospheric mantle source for the Zealandia intraplate basalts are based upon contemporaneous HIMU-like magmatism also having occurred in the formerly contiguous continental areas of Antarctica [Rocholl et al, 1995;Hart et al, 1997;Panter et al, 2000;Rocchi et al, 2002;Martin et al, 2013], East Australia and Tasmania [Lanyon et al, 1993;Zhang et al, 2001;Nasir et al, 2010] but not the intervening ocean basins. The source region is suggested to have been a mantle lithospheric domain that was located under Gondwana and has since been dismembered during separation of the Australia-Zealandia-Antarctica Gondwana margin at 85 Ma [Panter et al, 2006].…”

Section: Introductionmentioning

confidence: 99%

Metasomatized ancient lithospheric mantle beneath the young Zealandia microcontinent and its role in HIMU-like intraplate magmatism

Scott

Waight²,

Meer³

et al. 2014

Geochem. Geophys. Geosyst.

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There has been long debate on the asthenospheric versus lithospheric source for numerous intraplate basalts with ocean island basalt (OIB) and high time-integrated U/Pb (HIMU)-like source signatures that have erupted through the Zealandia continental crust. Analysis of 157 spinel facies peridotitic mantle xenoliths from 25 localities across Zealandia permits the first comprehensive regional description of the subcontinental lithospheric mantle (SCLM) and insights into whether it could be a source to the intraplate basalts. Contrary to previous assumptions, the Oligocene-Miocene Zealandia SCLM is highly heterogeneous. It is composed of a refractory craton-like domain (West Otago) adjacent to several moderately fertile domains (East Otago, North Otago, Auckland Islands). Each domain has an early history decoupled from the overlying Carboniferous and younger continental crust, and each domain has undergone varying degrees of depletion followed by enrichment. Clinopyroxene grains reveal trace element characteristics (low Ti/Eu, high Th/U) consistent with enrichment through reaction with carbonatite. This metasomatic overprint has a composition that closely matches HIMU in Sr, Pb 6 Nd isotopes. However, clinopyroxene Hf isotopes are in part highly radiogenic and decoupled from the other isotope systems, and also mostly more radiogenic than the intraplate basalts. If the studied spinel facies xenoliths are representative of the thin Zealandia SCLM, the melting of garnet facies lithosphere could only be the intraplate basalt source if it had a less radiogenic Hf-Nd isotope composition than the investigated spinel facies, or was mixed with asthenosphere-derived melts containing less radiogenic Hf.

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The petrology of high pressure xenoliths and associated Cenozoic basalts from Northeastern Tasmania

Cited by 10 publications

References 63 publications

Revisiting the electron microprobe method of spinel-olivine-orthopyroxene oxybarometry applied to spinel peridotitesk

Revisiting the electron microprobe method of spinel-olivine-orthopyroxene oxybarometry applied to spinel peridotitesk

Thermal Structure of Eastern Australia's Upper Mantle and Its Relationship to Cenozoic Volcanic Activity and Dynamic Topography

Metasomatized ancient lithospheric mantle beneath the young Zealandia microcontinent and its role in HIMU-like intraplate magmatism

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