Destruction of the Wyoming craton: Seismic evidence and geodynamic processes

Dave, R.; Li, Aibing

doi:10.1130/g38147.1

Cited by 53 publications

(47 citation statements)

References 31 publications

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“…Similar to the cratonic blocks beneath Congo, the Tanzania lithosphere has notably high Vs . The asymmetry of the Tanzania Craton agrees with prior work proposing that the craton may be thermally eroded along the Eastern Branch (e.g., Ebinger et al, ; Weeraratne et al, ); thermal erosion has also been suggested for other cratonic regions, including the North China and Wyoming Cratons (e.g., Dave & Li, ; Gao et al, ; Lee et al, ; Xu, ; Zhang et al, ). Geodynamic models suggest that prior cratonic root metasomatism enables thermal erosion to take place (e.g., Snyder et al, ; van Wijk et al, ; Wang et al, ), and we note that this region coincides with earlier Pan‐African collision and prior alteration (Collins & Piesarevsky, ; Koornneef et al, ; Porada, ; Rino et al, ).…”

Section: Discussionsupporting

confidence: 87%

Upper Mantle Earth Structure in Africa From Full‐Wave Ambient Noise Tomography

Emry

Shen

Nyblade

et al. 2019

Geochem Geophys Geosyst

152

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Our understanding of the tectonic development of the African continent and the interplay between its geological provinces is hindered by unevenly distributed seismic instrumentation. In order to better understand the continent, we used long‐period ambient noise full‐waveform tomography on data collected from 186 broadband seismic stations throughout Africa and surrounding regions to better image the upper mantle structure. We extracted empirical Green's functions from ambient seismic noise using a frequency‐time normalization method and retrieved coherent signal at periods of 7–340 s. We simulated wave propagation through a heterogeneous Earth using a spherical finite‐difference approach to obtain synthetic waveforms, measured the misfit as phase delay between the data and synthetics, calculated numerical sensitivity kernels using the scattering integral approach, and iteratively inverted for structure. The resulting images of isotropic, shear wave speed for the continent reveal segmented, low‐velocity upper mantle beneath the highly magmatic northern and eastern sections of the East African Rift System (EARS). In the southern and western sections, high‐velocity upper mantle dominates, and distinct, low‐velocity anomalies are restricted to regions of current volcanism. At deeper depths, the southern and western EARS transition to low velocities. In addition to the EARS, several low‐velocity anomalies are scattered through the shallow upper mantle beneath Angola and North Africa, and some of these low‐velocity anomalies may be connected to a deeper feature. Distinct upper mantle high‐velocity anomalies are imaged throughout the continent and suggest multiple cratonic roots within the Congo region and possible cratonic roots within the Sahara Metacraton.

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Section: Discussionsupporting

confidence: 87%

Upper Mantle Earth Structure in Africa From Full‐Wave Ambient Noise Tomography

Emry

Shen

Nyblade

et al. 2019

Geochem Geophys Geosyst

152

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“…Proposed explanations for the volcanic perimeter and stable, uplifted interior include lithosphere delamination along the plateau's margins (Levander et al, 2011), lithospheric thinning through transient heating and/or melt-induced erosion Roy et al, 2009;van Wijk et al, 2010;Wannamaker et al, 2008), and hydration of the lower crust (Jones et al, 2015). At the Wyoming craton, the Archean lithosphere may have been modified and eroded by processes related to both the Laramide orogeny (e.g., Humphreys et al, 2015) and, more recently, the Yellowstone hotspot (e.g., Dave & Li, 2016).…”

Section: Introductionmentioning

confidence: 99%

Long‐Period Rayleigh Wave Phase Velocity Tomography Using USArray

Babikoff

Dalton

2019

Geochem Geophys Geosyst

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Seismic models show that the shallow mantle beneath the contiguous United States is characterized by low velocities west of the Rocky Mountain Front, high velocities beneath the North American craton, and moderate wave speeds along the eastern seaboard. However, numerous questions remain, including the distribution of temperature and partial melt in the mantle that may explain the slower velocities in the west; the origin and depth extent of the western edge of the cratonic lithosphere; and explanations for slower velocities observed along the eastern seaboard. To investigate these questions, we have measured teleseismic Rayleigh wave phase and amplitude at USArray stations for periods of 25–180 s and calculated phase velocity using the Helmholtz tomography method. Notably, the new long‐period maps represent an opportunity to resolve mantle structure at sublithospheric depths and show differences relative to shorter periods in both the distribution of slow velocities in the west and the extent of fast velocities in the central United States. The maps are then used as a basis for comparing six recent 3‐D shear velocity models of the contiguous United States, from which we predict phase velocities. While predictions from surface‐wave models agree best with our observations at short and intermediate periods, the longest‐period maps are most similar in amplitude to body‐wave models.

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“…Archean cratons are usually underlain by thick (>200 km), cold, chemically refractory, and high‐velocity subcontinental lithospheric mantle (SCLM), which prevents cratonic lithosphere from being recycled by mantle convection for billions of years (Griffin et al, ; Lee et al, ; Yuan & Romanowicz, ). However, the reactivation of Archean cratons, which could result in the removal of a large part of SCLM, has been suggested to take place in many Archean cratons (Chen, ; Dave & Li, ; Gao et al, ; Guo, Afonso, et al, ; Lei, ; Zhao et al, ; Zheng et al, ; Zhu et al, ).…”

Section: Introductionmentioning

confidence: 99%

“…Archean cratons are usually underlain by thick (>200 km), cold, chemically refractory, and high-velocity subcontinental lithospheric mantle (SCLM), which prevents cratonic lithosphere from being recycled by mantle convection for billions of years Lee et al, 2001;Yuan & Romanowicz, 2010). However, the reactivation of Archean cratons, which could result in the removal of a large part of SCLM, has been suggested to take place in many Archean cratons (Chen, 2010;Dave & Li, 2016;Gao et al, 2004;Lei, 2012;Zhao et al, 2009;Zheng et al, 2007;Zhu et al, 2011). observations suggest that lithospheric rejuvenation also occurs at the margins of Ordos during the late Cenozoic, resulting in significant intracratonic heterogeneities (Dong et al, 2014;Yu & Chen, 2016).…”

Section: Introductionmentioning

confidence: 99%

Lithospheric Structure of the Northern Ordos From Ambient Noise and Teleseismic Surface Wave Tomography

Guo

Chen

et al. 2018

JGR Solid Earth

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We constructed a high‐resolution 3‐D Vs model of the northern Ordos block and its surrounding areas by surface wave tomography, which reveals significant intracratonic heterogeneities. In the western Ordos, the lithosphere thickness is ~200 km with shear velocities comparable to the high velocities of other Archean cratons worldwide. However, the lithosphere thins gradually toward the east and Vs drops by 2–3% in the uppermost mantle beneath the eastern Ordos, coincident with the high surface heat flow (~68 mW/m2 in average) there. This observation suggests that the thick, cratonic keel is only locally preserved beneath the western Ordos, and the eastern part of the Ordos seems to undergo local rejuvenation. At greater depths (>180 km), a low‐velocity channel is observed beneath the high‐velocity keel of the Ordos. Beneath the Datong volcanoes, a low‐velocity anomaly is observed, dipping westward with depth and closely following the slope of the lithosphere beneath the northern Ordos. This prominent low velocity is connected with the low‐velocity zone beneath the northern Ordos, which is further connected with the low‐velocity zone beneath the northeastern Tibetan Plateau (NET). We propose that the asthenosphere beneath the NET flows toward the northern Ordos in response to the continuous northward convergence of the Indian‐Eurasian continents, and the asthenosphere flows upward following the eastward thinning lithosphere which leads to decompression partial melting, which migrates upward to feed the Datong volcanoes. The significant variations of the lithospheric thickness of the Ordos block may control the distribution of the asthenospheric flow.

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Destruction of the Wyoming craton: Seismic evidence and geodynamic processes

Cited by 53 publications

References 31 publications

Upper Mantle Earth Structure in Africa From Full‐Wave Ambient Noise Tomography

Upper Mantle Earth Structure in Africa From Full‐Wave Ambient Noise Tomography

Long‐Period Rayleigh Wave Phase Velocity Tomography Using USArray

Lithospheric Structure of the Northern Ordos From Ambient Noise and Teleseismic Surface Wave Tomography

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