A comparison of oceanic and continental mantle lithosphere

Fischer, K. M.; Rychert, C.; Dalton, C. A.; Miller, Meghan; Beghein, Caroline; Schutt, D.

doi:10.1016/j.pepi.2020.106600

Cited by 32 publications

(32 citation statements)

References 219 publications

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“…The cratonic LAB, estimated to exist at depths greater than 150 km (e.g., Dalton et al, 2017;Fischer et al, 2020), is one possible explanation for the weak NVGs observed in this depth range. We find that negative phases in this depth range are absent (with one exception) in non-cratonic regions, presumably because the lithosphere is thinner.…”

Section: Mechanisms For Lower-lithospheric Velocity Gradientsmentioning

confidence: 97%

“…In tectonically active regions, this NVG is often interpreted as the lithosphere‐asthenosphere boundary (LAB). However, in cratonic regions heat flow and xenolith constraints require the LAB to be much deeper, placing this NVG in the mid‐lithosphere (e.g., Abt et al., 2010; Cooper & Miller, 2014; Eilon et al., 2018; Fischer et al., 2020; Hansen et al., 2015; Hopper & Fischer, 2015; Karato et al., 2015; Kind & Yuan, 2018; Miller & Eaton, 2010; Rader et al., 2015; Rychert & Shearer, 2009; Selway et al., 2015; Wolbern et al., 2012).…”

Section: Introductionmentioning

confidence: 99%

“…In addition to MLDs, in this study, we also examine deeper discontinuities in the cratonic mantle. One of these is a potential NVG associated with the base of the lithosphere, which is thought to lie at depths of 150–350 km based on velocity and attenuation tomography (e.g., Dalton et al., 2017; Fischer et al., 2020; Gung et al., 2003). A second mantle discontinuity is a positive velocity gradient (PVG) that has been observed beneath the continents in the 150–300 km depth range with both body waves (e.g., Revenaugh & Jordan, 1991) and surface waves (e.g., Dalton et al., 2017; Gung et al., 2003), a feature often associated with the Lehman discontinuity (Lehmann, 1959).…”

Section: Introductionmentioning

confidence: 99%

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Global Patterns in Cratonic Mid‐Lithospheric Discontinuities From Sp Receiver Functions

Krueger

Gama

Fischer

2021

Geochem Geophys Geosyst

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The goal of this study is to constrain the origins of layering in the seismic velocity structure within the cratonic mantle lithosphere (i.e. mid‐lithospheric discontinuities [MLDs]). For long‐lived stations in cratons worldwide, we calculated S‐to‐P converted phase receiver function stacks using time domain deconvolution and a k‐means algorithm to select robust, consistent receiver functions. Negative MLDs appear in only 50% of the receiver function stacks, indicating that negative MLDs are common but intermittent. The negative MLDs correspond to shear velocity drops of 1%–4%, which could be caused by layers of minerals created by metasomatism, although vertical layering in seismic anisotropy cannot be ruled out. In craton interiors, negative MLDs have a lower amplitude (<3% velocity drops) and can be explained by metasomatism of the original Archean mantle. Negative MLD amplitudes increase with decreasing upper mantle shear velocity (toward the outer margins of the cratons), but do not depend on the age of the craton. Thus, negative MLD amplitudes are not dominated by age‐related variations in the cratonic mantle composition, and, instead, are more strongly correlated with proximity to tectonic and metasomatic activity that occurred long after craton formation. Negative MLDs are less numerous among stations that have Paleoproterozoic and Archean thermotectonic ages, consistent with the view that shallow release of slab‐derived fluids during early “warm” subduction was less favorable for negative MLD formation. We also observe velocity gradients below 150 km at stations in craton boundaries and interiors, indicating the presence of seismic velocity changes at the cratonic lithosphere‐asthenosphere boundary and/or Lehmann discontinuity.

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Section: Mechanisms For Lower-lithospheric Velocity Gradientsmentioning

confidence: 97%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Global Patterns in Cratonic Mid‐Lithospheric Discontinuities From Sp Receiver Functions

Krueger

Gama

Fischer

2021

Geochem Geophys Geosyst

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“…The physical properties (such as age, thickness, composition, temperature, and viscosity) of continental lithosphere contain crucial information about its formation and evolution, and more fundamentally, about Earth's tectonic dynamics through geological time. The thickness of cratonic lithosphere, revealed by fast seismic velocities, is on average ∼200–250 km (e.g., Cammarano & Romanowicz, 2007; Bedle & van der Lee, 2009; Fischer et al., 2020; Hamza & Vieira, 2012; Kind et al., 2020; Schaeffer & Lebedev, 2014), roughly in agreement with estimates from xenolith analysis (O'Reilly & Griffin, 2010; Crépisson et al., 2014), heat flow (Mareschal & Jaupart, 2004), and magnetotelluric data (Adetunji et al., 2014; Evans et al., 2019). It is commonly agreed that cratonic lithosphere is thicker, colder, and more stable than younger continental lithosphere.…”

Section: Introductionmentioning

confidence: 99%

Lithospheric Formation and Evolution of Eastern North American Continent

Gao

2021

Geophysical Research Letters

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Lithospheric layering contains critical information about continental formation and evolution. However, discrepancies on the depth distributions of lithospheric layers have significantly limited our understanding of possible tectonic connections among the layers. Here, we construct a high‐resolution shear velocity model of eastern North America using full‐wave ambient noise simulation and inversion by integrating onshore and offshore seismic datasets. Our new model reveals large lateral variations of lithosphere thickness approximately across the major tectonic boundaries, strong low‐velocity anomalies underlying the thinner lithosphere, and multiple low‐velocity layers within the continental lithosphere. We suggest that the present mantle lithosphere beneath eastern North America was formed and modified through multiple stages of tectonic processes, among which metasomatism may have significantly contributed to the observed intralithospheric low‐velocity layers. The sharp thickness variation of lithosphere promoted edge‐driven mantle convection, which has been consequently modifying the overlying mantle lithosphere and further sharpening the gradient of lithosphere thickness

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“…Different spreading rates are predicted to result in variations in associated dynamics and ridge processes (Parmentier & Morgan, 1990), with important implications for the formation and evolution of the lithosphere-asthenosphere system. Additional measurements of attenuation at a broad range of frequencies and from different aged lithosphere formed at different spreading rates are required to settle long-held debates regarding the nature of the lithosphere-asthenosphere system (e.g., Abers et al, 2014;Artemieva, 2006;Auer et al, 2014;Beghein et al, 2014;Burgos et al, 2020;Cline et al, 2018;Eaton et al, 2009;Faul & Jackson, 2005;Fischer et al, 2020;Ford et al, 2010;Gaherty et al, 1996;Holtzman et al, 2003;Karato & Park, 2019;Kawakatsu et al, 2009;Priestley & McKenzie, 2013;Rychert et al, 2007;Rychert et al, 2010;Rychert et al, 2020;Rychert & Shearer, 2009;Sarafian et al, 2015;Stern et al, 2015;Yamauchi & Takei, 2016).…”

Section: 1029/2021gc010085mentioning

confidence: 99%

Seismic Attenuation at the Equatorial Mid‐Atlantic Ridge Constrained by Local Rayleigh Wave Analysis From the PI‐LAB Experiment

Saikia

Rychert

Harmon

et al. 2021

Geochem Geophys Geosyst

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Determining the physical and chemical properties of the lithosphere and the asthenosphere is crucial for a better understanding of plate tectonics. Most of the Earth's tectonic plates are comprised of oceanic lithosphere, which is thought to have a relatively simple tectonic history and composition. The relative simplicity of the oceanic upper mantle makes it the ideal place for studying the lithosphere-asthenosphere system. Simple thermal models such as half space cooling or plate cooling are effective at explaining a substantial amount of the geophysical observations in the oceans (Dalton et al., 2014;Parsons & Sclater, 1977;Stein & Stein, 1992) and the composition of the mantle is well constrained from the volcanic outputs at mid-ocean ridges (Klein & Langmuir, 1987). Mid-ocean ridges are also particularly important for our understanding of the plate given that this is where the plate is formed from the upwelling of asthenospheric mantle (

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A comparison of oceanic and continental mantle lithosphere

Cited by 32 publications

References 219 publications

Global Patterns in Cratonic Mid‐Lithospheric Discontinuities From Sp Receiver Functions

Global Patterns in Cratonic Mid‐Lithospheric Discontinuities From Sp Receiver Functions

Lithospheric Formation and Evolution of Eastern North American Continent

Seismic Attenuation at the Equatorial Mid‐Atlantic Ridge Constrained by Local Rayleigh Wave Analysis From the PI‐LAB Experiment

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