A Global View of the Lithosphere-Asthenosphere Boundary

Rychert, C.; Shearer, Peter M.

doi:10.1126/science.1169754

Cited by 359 publications

(324 citation statements)

References 29 publications

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“…Observations of the LAB in P receiver functions are not unusual. Such observations have also been obtained worldwide by Rychert and Shearer (2009). S receiver functions are very useful for the verification of LAB observations, because of the absence of multiples (see e.g.…”

Section: Validation Assessment Of the Moho Lab 410 Km And 660 Km DImentioning

confidence: 99%

Seismic signature of the collision between the east Tibetan escape flow and the Sichuan Basin

Zhang

Yuan

Chen

et al. 2010

Earth and Planetary Science Letters

212

137

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GPS displacement vectors show that the crust in east Tibet is being squeezed in an easterly direction by the northward motion of the Indian plate, and the Sichuan Basin is resisting this stream and redirecting it mainly towards Indochina. The Longmen Shan, containing the steepest rise to the high plateau anywhere in Tibet, results from the strong interaction between the east Tibetan escape flow and the rigid Yangtze block (Sichuan Basin), but the kinematics and dynamics of this interaction are still the subject of some debates. We herein present results from a dense passive-source seismic profile from the Sichuan Basin into eastern Tibet in order to study the deep structure of this collision zone. Using P and S receiver function

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Section: Validation Assessment Of the Moho Lab 410 Km And 660 Km DImentioning

confidence: 99%

Seismic signature of the collision between the east Tibetan escape flow and the Sichuan Basin

Zhang

Yuan

Chen

et al. 2010

Earth and Planetary Science Letters

212

137

View full text Add to dashboard Cite

show abstract

“…On the other hand the values provided by Dundar et al (2011) using S-wave receiver functions and by a recent Rayleigh wave tomography ) are similar to ours. Rychert & Shearer (2009) have compiled a global map of the LAB depth from P receiver function observations. They found LAB depths of 80-95 km under active tectonic areas.…”

Section: A Shallow Lithosphere-asthenosphere Boundary (Lab)mentioning

confidence: 99%

Crustal thickness and images of the lithospheric discontinuities in the Gibraltar arc and surrounding areas

Mancilla

Stich

Morales

et al. 2015

Geophysical Journal International

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S U M M A R YThe Gibraltar arc and surrounding areas are a complex tectonic region and its tectonic evolution since Miocene is still under debate. Knowledge of its lithospheric structure will help to understand the mechanisms that produced extension and westward motion of the Alboran domain, simultaneously with NW-SE compression driven by Africa-Europe plates convergence. We perform a P-wave receiver function analysis in which we analyse new data recorded at 83 permanent and temporary seismic broad-band stations located in the South of the Iberian peninsula. These data are stacked and combined with data from a previous study in northern Morocco to build maps of thickness and average v P /v S ratio for the crust, and cross-sections to image the lithospheric discontinuities beneath the Gibraltar arc, the Betic and Rif Ranges and their Iberian and Moroccan forelands. Crustal thickness values show strong lateral variations in the southern Iberia peninsula, ranging from ∼19 to ∼46 km. The Variscan foreland is characterized by a relatively flat Moho at ∼31 km depth, and an average v P /v S ratio of ∼1.72, similar to other Variscan terranes, which may indicate that part of the lower crustal orogenic root was lost. The thickest crust is found at the contact between the Alboran domain and the External Zones of the Betic Range, while crustal thinning is observed southeastern Iberia (down to 19 km) and in the Guadalquivir basin where the thinning at the Iberian paleomargin could be still preserved. In the cross-sections, we see a strong change between the eastern Betics, where the Iberian crust underthrusts and couples to the Alboran crust, and the western Betics, where the underthrusting Iberian crust becomes partially delaminated and enters into the mantle. The structures largely mirror those on the Moroccan side where a similar detachment was observed in northern Morocco. We attribute a relatively shallow strong negativepolarity discontinuity to the lithosphere-asthenosphere boundary. This means relatively thin lithosphere ranging from ∼50 km thickness in southeastern Iberia and northeastern Morocco to ∼90-100 km beneath the western Betics and the Rif, with abrupt changes of ∼30 km under the central Betics and northern Morocco. Our observations support a geodynamic scenario where in western Betics oceanic subduction has developed into ongoing continental subduction/delamination while in eastern Betics this process is inactive.

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“…Recent studies have suggested a thickness of 200-250 km by incorporating the effects of anisotropy on seismic velocities 61 . However, at shallower depths (100-140 km) beneath these cratons, strong conversions from compressional-to-shear wave (P-S) and shear-to-compressional wave (S-P) have been found [62][63][64] . This led some researchers to believe that the thickness of the cratonic lithosphere might be less than expected 62 , which contradicts tomographic and other geophysical and geochemical observations.…”

Section: Stability Of Cratonsmentioning

confidence: 99%

“…However, at shallower depths (100-140 km) beneath these cratons, strong conversions from compressional-to-shear wave (P-S) and shear-to-compressional wave (S-P) have been found [62][63][64] . This led some researchers to believe that the thickness of the cratonic lithosphere might be less than expected 62 , which contradicts tomographic and other geophysical and geochemical observations. Therefore, such conversions have been recently attributed to the presence of an intracontinental discontinuous zone of either partial melt or dehydrated material, or both, around depths of 100 km (ref.…”

Section: Stability Of Cratonsmentioning

confidence: 99%

Understanding Deep Earth Dynamics:A Numerical Modelling Approach

Singh¹,

Agrawal²,

Ghosh³

2017

Current Science

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Enhancement in computing power and better data availability have paved the way for deciphering the earth's deeper dynamics and have provided viable explanations for various surface phenomena. Tools such as seismic tomography, numerical modelling and geophysical observations such as stresses, gravity anomalies, heat flow, etc. have helped us in addressing the mechanisms of plate driving forces, anomalous geoid variations, cratonic stability, topographic support, intraplate earthquakes and similar outstanding issues in geodynamics. Due to lack of direct observations from deep earth, numerical modelling has aided considerably in learning about subsurface processes. With better algorithms being developed everyday, it is the right time to tap their potential to push the frontiers of human knowledge.

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A Global View of the Lithosphere-Asthenosphere Boundary

Cited by 359 publications

References 29 publications

Seismic signature of the collision between the east Tibetan escape flow and the Sichuan Basin

Seismic signature of the collision between the east Tibetan escape flow and the Sichuan Basin

Crustal thickness and images of the lithospheric discontinuities in the Gibraltar arc and surrounding areas

Understanding Deep Earth Dynamics:A Numerical Modelling Approach

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