Extensive Magmatic Heating of the Lithosphere Beneath the Hawaiian Islands Inferred From Salt Lake Crater Mantle Xenoliths

Guest, Imani; Ito, Garrett; Garcia, Michael O.; Hellebrand, E.

doi:10.1029/2020gc009359

Cited by 6 publications

(3 citation statements)

References 42 publications

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“…1C]. This thinner lithosphere is consistent with flexural and gravimetric observations, as well as with xenolith-based thermobarometric results, which indicate that temperatures of 1000° to 1100°C occur at depths of 45 to 55 km beneath Hawaii ( 33 , 34 ). In contrast to the Icelandic example, this discrepancy suggests that, locally, zLAB1 is notably shallower than expected beneath Hawaii.…”

Section: Resultssupporting

confidence: 87%

Destruction and regrowth of lithospheric mantle beneath large igneous provinces

Stephenson,

Ball,

Richards

2023

Sci. Adv.

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Large igneous provinces (LIPs) are formed by enormous (i.e., frequently >10 6 km 3 ) but short-lived magmatic events that have profound effects upon global geodynamic, tectonic, and environmental processes. Lithospheric structure is known to modulate mantle melting, yet its evolution during and after such dramatic periods of magmatism is poorly constrained. Using geochemical and seismological observations, we find that magmatism is associated with thin (i.e., ≲80 km) lithosphere and we reveal a striking positive correlation between the thickness of modern-day lithosphere beneath LIPs and time since eruption. Oceanic lithosphere rethickens to 125 km, while continental regions reach >190 km. Our results point to systematic destruction and subsequent regrowth of lithospheric mantle during and after LIP emplacement and recratonization of the continents following eruption. These insights have implications for the stability, age, and composition of ancient, thick, and chemically distinct lithospheric roots, the distribution of economic resources, and emissions of chemical species that force catastrophic environmental change.

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Section: Resultssupporting

confidence: 87%

Destruction and regrowth of lithospheric mantle beneath large igneous provinces

Stephenson,

Ball,

Richards

2023

Sci. Adv.

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“…The lack of features beneath the swell in this depth range shows that the excess elevation is not created by reheating or replacement of the upper lithosphere. Note that we have no doubt about local reheating around deep magma chambers, as observed by mantle xenoliths from the island of Oahu (Guest et al., 2020); however, these results are not applicable to the main, broad swell. Dehydration of the newly formed lithosphere during seafloor spreading is expected at depths shallower than about 70 km (Hirschmann, 2010; Katz et al., 2003) by migration of the pressure‐release melt to the surface to form the crust.…”

Section: Resultsmentioning

confidence: 60%

On the Origin of the Hawaiian Swell: Lithosphere and Asthenosphere Seismic Structure From Rayleigh Wave Dispersion

Chen,

Forsyth

2024

JGR Solid Earth

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In this study, we revisit the shear‐wave velocity structure of the lithosphere and asthenosphere surrounding the Hawaiian hotspot and Hawaiian swell using Rayleigh wave data spanning periods of 20–125 s from the PLUME project. A primary goal of this investigation is to probe the origin of the Hawaiian swell and the mechanism that elevates the topography, providing insights into mantle dynamics beneath hotspot swells. In the shear velocity model, the 30–70 km depth range is largely featureless with weak and local anomalies, indicating that the elevation of the Hawaiian swell cannot be attributed to upper lithospheric reheating or replacement. In contrast, at 80–150 km depth, a pronounced region of anomalously low velocities is well‐resolved, with the lowest velocities found beneath the Hawaii‐Maui‐Molokai part of the island chain. Minimum shear velocities are approximately 4.0 km/s at 100–120 km depth, which is an ∼8%‐10% velocity decrease relative to the surrounding velocities away from the swell. This pattern suggests that hot, buoyant mantle from deeper plume sources laterally spread out near the top of the normal oceanic asthenosphere. We find that the low‐velocity pattern in the asthenosphere exhibits a strong correlation with the overall shape of the Hawaiian swell topography. Assuming that density anomalies are proportional to shear velocity anomalies, we demonstrate that the anomalous elevation of the swell can be explained by the uplift of a 30‐km‐thick elastic plate loaded from below by this buoyant, low‐seismic‐velocity layer in the asthenosphere.

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“…We must also address that other studies have suggested lab-derived low-temperature plasticity is perfectly consistent with Earth's lithosphere, and rather does not reproduce observations of flexure at Hawaii because thermal erosion by the Hawaiian plume significantly weakens the Hawaiian lithosphere by modifying the ∼90 Myr thermal structure (Guest et al, 2020;Hunter & Watts, 2016;Pleus et al, 2020). This would cause viscoelastic loading models to overestimate lithospheric strength and underestimate flexure if they do not account for the anomalous thermal structure.…”

Section: Rheological Equationsmentioning

confidence: 91%

Seismic Strain Rate and Flexure at the Hawaiian Islands Constrain the Frictional Coefficient

Bellas

Zhong

2021

Geochem Geophys Geosyst

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Flexure occurs on intermediate geologic timescales (∼1 Myr) due to volcanic‐island building at the Island of Hawaii, and the deformational response of the lithosphere is simultaneously elastic, plastic, and ductile. At shallow depths and low temperatures, elastic deformation transitions to frictional failure on faults where stresses exceed a threshold value, and this complex rheology controls the rate of deformation manifested by earthquakes. In this study, we estimate the seismic strain rate based on earthquakes recorded between 1960 and 2019 at Hawaii, and the estimated strain rate with 10−18–10−15 s−1 in magnitude exhibits a local minimum or neutral bending plane at 15 km depth within the lithosphere. In comparison, flexure and internal deformation of the lithosphere are modeled in 3D viscoelastic loading models where deformation at shallow depths is accommodated by frictional sliding on faults and limited by the frictional coefficient (μf), and at larger depths by low‐temperature plasticity and high‐temperature creep. Observations of flexure and the seismic strain rate are best‐reproduced by models with μf = 0.3 ± 0.1 and modified laboratory‐derived low‐temperature plasticity. Results also suggest strong lateral variations in the frictional strength of faults beneath Hawaii. Our models predict a radial pattern of compressive stress axes relative to central Hawaii consistent with observations of earthquake pressure (P) axes. We demonstrate that the dip angle of this radial axis is essential to discerning a change in the curvature of flexure, and therefore has implications for constraining lateral variations in lithospheric strength.

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Extensive Magmatic Heating of the Lithosphere Beneath the Hawaiian Islands Inferred From Salt Lake Crater Mantle Xenoliths

Cited by 6 publications

References 42 publications

Destruction and regrowth of lithospheric mantle beneath large igneous provinces

Destruction and regrowth of lithospheric mantle beneath large igneous provinces

On the Origin of the Hawaiian Swell: Lithosphere and Asthenosphere Seismic Structure From Rayleigh Wave Dispersion

Seismic Strain Rate and Flexure at the Hawaiian Islands Constrain the Frictional Coefficient

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