Mantle transition zone structure beneath Tanzania, east Africa

Owens, Thomas; Nyblade, A.; Gurrola, H.; Langston, Charles A.

doi:10.1029/1999gl005429

Cited by 109 publications

(128 citation statements)

References 17 publications

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“…[12] A study of mantle transition zone discontinuities by Owens et al [2000] using receiver function stacks and the tomography model from Ritsema et al [1998] found evidence for a 30-40 km depression of the 410 km discontinuity, a result that was latter corroborated by Huerta et al…”

Section: Previous Seismic Studiessupporting

confidence: 63%

“…But the limited vertical resolution in these models makes it difficult to determine if the LWA extends into the mantle transition zone and connects to anomalous upper mantle structure beneath eastern Africa. Regional studies of upper mantle structure in eastern Africa, on the other hand, have imaged a LWA extending from shallow depths downward into the transition zone but have not been able to ascertain if the anomaly continues through the transition zone to connect with the superplume structure in the lower mantle [e.g., Ritsema et al, 1998;Owens et al, 2000;Weeraratne et al, 2003;Park and Nyblade, 2006;Huerta et al, 2009;Adams et al, 2012].…”

Section: Introductionmentioning

confidence: 99%

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The P and S wave velocity structure of the mantle beneath eastern Africa and the African superplume anomaly

Mulibo

Nyblade

2013

Geochem Geophys Geosyst

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P and S relative arrival time residuals from teleseismic earthquakes recorded on over 60 temporary AfricaArray broadband seismic stations deployed in Uganda, Tanzania, and Zambia between 2007 and 2011 have been inverted, together with relative arrival time residuals from earthquakes recorded by previous deployments, for a tomographic image of mantle wave speed variations extending to a depth of 1200 km beneath eastern Africa. The image shows a low‐wave speed anomaly (LWA) well developed at shallow depths (100–200 km) beneath the Eastern and Western branches of the Cenozoic East African rift system and northwestern Zambia, and a fast wave speed anomaly at depths ≤ 350 km beneath the central and northern parts of the East African Plateau and the eastern and central parts of Zambia. At depths ≥350 km the LWA is most prominent under the central and southern parts of the East African Plateau and dips to the southwest beneath northern Zambia, extending to a depth of at least 900 km. The amplitude of the LWA is consistent with a ∼150–300 K thermal perturbation, and its depth extent indicates that the African superplume, originally identified as a lower mantle anomaly, is likely a whole mantle structure. A superplume extending from the core‐mantle boundary to the surface implies an origin for the Cenozoic extension, volcanism, and plateau uplift in eastern Africa rooted in the dynamics of the lower mantle.

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Section: Previous Seismic Studiessupporting

confidence: 63%

Section: Introductionmentioning

confidence: 99%

The P and S wave velocity structure of the mantle beneath eastern Africa and the African superplume anomaly

Mulibo

Nyblade

2013

Geochem Geophys Geosyst

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“…The utility of most other phases is still more limited due to either interference or low signal-to-noise levels, although it is often used to augment teleseismic P data PP (e.g., Gurrola et al, 1994;Owens et al, 2000). Useful structural information has on occasion also been extracted from regional P (e.g., Park and Levin, 2001) and PKP (e.g., Park and Levin, 2000) using 'receiver function'-style approaches.…”

Section: Geometrical Preliminariesmentioning

confidence: 98%

Theory and Observations - Seismology and the Structure of the Earth: Teleseismic Body-Wave Scattering and Receiver-Side Structure

Bostock

2015

Treatise on Geophysics

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“…Утонение переходного слоя в целом подтверждается антикорреляцией его верхней и нижней границы [Shen et al, 1998;Li et al, 2000Li et al, , 2003Owens et al, 2000;Hooft et al, 2003], хотя в некоторых регионах (например, в западной части Северной Америки) границы 410 и 660 км антикоррелиру-ются друг с другом не всегда [Houser et al, 2008].…”

Section: подлитосферные расплавные аномалииunclassified

The latest geodynamics in Central Asia: primary and secondary mantle melting anomalies in the context of orogenesis, rifting, and lithospheric plate motions and interactions

Chuvashova¹,

Рассказов²,

Сунь³

2017

Geodin. tektonofiz.

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A comprehensive model for deep dynamics in Asia has been developed from the data on the evolution of melting anomalies in the context of lithospheric plate motions, interactions, orogeny, and rifting. The key components of our model are the primary (transition layer) and secondary (upper mantle) melting anomalies (Gobi, Baikal, and North Transbaikalia; and Hangay, Sayan, and Vitim, respectively). It is inferred that the primary melting anomalies originated at the beginning of the latest geodynamic stage (ca. 90 Ma) as a result of the transition layer distortion by lower mantle flows. Such primary anomalies were caused by avalanche collapses of the slab material that had been stagnated under the closed fragments of the Solonker, Ural-Mongolian paleooceans and the Mongol-Okhotsk Bay of Paleopacific. The secondary melting anomalies occurred due to the Early-Middle Miocene structural reorganization in the Pacific-Asian and Indo-Asian interaction zones. The primary melting anomalies governed the spatial distribution of forces and processes of the latest geodynamic stage. The secondary melting anomalies resulted from the lithospheric motions relative to the primary anomalies and provided for the development of orogeny and rifting. The BaikalMongolian corridor of asthenospheric flows was limited by the lateral zones of convergent interactions between India and Asia in the southwest, and North America and Asia in the northeast. In these lateral zones, Late Phanerozoic paleoslabs and ascending mantle fluxes were revealed in the transition layer, as well as in the upper mantle, without any destruction by the asthenospheric flows.

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Mantle transition zone structure beneath Tanzania, east Africa

Abstract: Abstract.We apply a three-dimensional stacking method to receiver functions from the Tanzania

Cited by 109 publications

References 17 publications

The P and S wave velocity structure of the mantle beneath eastern Africa and the African superplume anomaly

The P and S wave velocity structure of the mantle beneath eastern Africa and the African superplume anomaly

Theory and Observations - Seismology and the Structure of the Earth: Teleseismic Body-Wave Scattering and Receiver-Side Structure

The latest geodynamics in Central Asia: primary and secondary mantle melting anomalies in the context of orogenesis, rifting, and lithospheric plate motions and interactions

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