Do Olivine Crystallization Temperatures Faithfully Record Mantle Temperature Variability?

Matthews, Simon; Wong, K.C.; Shorttle, Oliver; Edmonds, Marie; Maclennan, John

doi:10.1029/2020gc009157

Cited by 33 publications

(26 citation statements)

References 169 publications

(426 reference statements)

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“…The INVMEL-v12 algorithm does not take into account the presence of pyroxenitic or harzburgitic lithologies within the upper mantle. If pyroxenite or harzburgite occur within the source region, recovered values of T p will be over-or under-estimates, respectively (Matthews et al, 2021). In summary, accurately constrained source compositions are required to improve the reliability of absolute T p and a estimates.…”

Section: Resultsmentioning

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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Section: Resultsmentioning

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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“…To address whether variations in melting parameters could explain the spatial variability in the contribution of pyroxenitic melts to the Galápagos Archipelago, we calculate the proportion of pyroxenite-derived melt that results from melting of a two-component mantle under various conditions. Calculations were performed using the pymelt Python module (Matthews et al, 2020), and recent empirical parameterizations for the melting of a lherzolitic peridotite and silica-deficient pyroxenite (KLB-1 and KG1, respectively; Matthews et al, 2021). We ran the calculations over a range of mantle potential temperatures (T P = 1,400-1,460°C) and lithospheric thicknesses (46-60 km; ∼1.5-1.85 GPa) appropriate to the Galápagos Archipelago (Gibson & Geist, 2010;Gibson et al, 2012Gibson et al, , 2015Herzberg & Asimow, 2008;Vidito et al, 2013), and consider how these conditions may influence the relative contribution of melts from a mixed peridotite-pyroxenite mantle source (Figure 9).…”

Section: Variations In Source Pyroxenite Proportionsmentioning

confidence: 99%

Geochemical Constraints on the Structure of the Earth's Deep Mantle and the Origin of the LLSVPs

Gleeson

Soderman

Matthews

et al. 2021

Geochem Geophys Geosyst

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“…pyroxenite-derived melt that results from melting of a two-component mantle under various conditions. Calculations were performed using the pymelt Python module (Matthews et al, 2020), and recent empirical parameterisations for the melting of a lherzolitic peridotite and silicaundersaturated pyroxenite (KLB-1 and KG1, respectively; Matthews et al, 2021). We ran the calculations over a range of mantle potential temperatures (TP = 1400 -1460 o C) and lithospheric thicknesses (46 -60 km; ~1.5 -1.85 GPa) appropriate to the Galápagos Archipelago (Gibson et al, 2015(Gibson et al, , 2012Gibson and Geist, 2010;Herzberg and Asimow, 2008;Vidito et al, 2013), and consider how these conditions may influence the relative contribution of melts from a mixed peridotitepyroxenite mantle source.…”

Section: Variations In Source Pyroxenite Proportionsmentioning

confidence: 99%

Geochemical constraints on the structure of the Earth’s deep mantle and the origin of the LLSVPs

Gleeson¹,

Soderman²,

Matthews³

et al. 2022

Preprint

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Geophysical analysis of the Earth’s lower mantle has revealed the presence of two superstructures characterized by low shear wave velocities on the core-mantle boundary. These Large Low Shear Velocity Provinces (LLSVPs) play a crucial role in the dynamics of the lower mantle and act as the source region for deep-seated mantle plumes. However, their origin, and the characteristics of the surrounding deep mantle, remain enigmatic. Mantle plumes located above the margins of the LLSVPs display evidence for the presence of this deep-seated, thermally and/or chemically heterogeneous mantle material ascending into the melting region. As a result, analysis of the spatial geochemical heterogeneity in OIBs provides constraints on the structure of the Earth’s lower mantle and the origin of the LLSVPs. In this study, we focus on the Galápagos Archipelago in the eastern Pacific, where bilateral asymmetry in the radiogenic isotopic composition of erupted basalts has been linked to the presence of LLSVP material in the underlying plume. We show, using spatial variations in the major element contents of high-MgO basalts, that the isotopically enriched south-western region of the Galápagos mantle – assigned to melting of LLSVP material – displays no evidence for lithological heterogeneity in the mantle source. As such, it is unlikely that the Pacific LLSVP represents a pile of subducted oceanic crust. Clear evidence for a lithologically heterogeneous mantle source is, however, found in the north-central Galápagos, indicating that a recycled crustal component is present near the eastern margin of the Pacific LLSVP, consistent with seismic observations.

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Do Olivine Crystallization Temperatures Faithfully Record Mantle Temperature Variability?

Abstract: Hawaiian olivines crystallize at hotter temperatures than olivines in MORB • Models are developed to link crystallization temperature to mantle temperature • Mantle plumes may have had a similar distribution of temperatures throughout the Phanerozoic

Cited by 33 publications

References 169 publications

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

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

Geochemical Constraints on the Structure of the Earth's Deep Mantle and the Origin of the LLSVPs

Geochemical constraints on the structure of the Earth’s deep mantle and the origin of the LLSVPs

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