Joint inversion of teleseismic and GOCE gravity data: application to the Himalayas

Basuyau, C.; Diament, M.; Tiberi, Christel; Hetényi, György; Vergne, Jérôme; Peyrefitte, A.

doi:10.1093/gji/ggs110

Cited by 30 publications

(24 citation statements)

References 61 publications

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“…A global, low-resolution (2 ∘ × 2 ∘ ) model using this approach displays large variations in the effective elastic thickness on the continents, with values ranging between 10 and 150 km (Audet, 2014). The GOCE gravity data are especially sensitive to boundaries within the lithosphere (Barzaghi et al, 2015;Basuyau et al, 2013). A similar distribution and data range was obtained for a local model by Kirby and Swain (2009) using gravity and elevation data for North America.…”

Section: Introductionmentioning

confidence: 63%

Weakened Lithosphere Beneath Greenland Inferred From Effective Elastic Thickness: A Hot Spot Effect?

Steffen

Audet

Lund

2018

Geophysical Research Letters

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The effective elastic thickness (Te) of the lithosphere provides geophysical information about long‐term flexural strength and can be used to constrain thermorheological properties of the lithosphere. Te is typically calculated from the spectral analysis of gravity and topography data; variations in Te are, however, not well resolved in Greenland due to poor constraints on crustal structure (including crustal thickness) and complications due to ice loading. In addition, geological and geophysical constraints on the tectonic history of Greenland are sparse due to the thick ice cover. Here we use the global gravity model EIGEN‐6C4 together with a new model of the crust‐mantle boundary to obtain a high‐resolution Te map of Greenland. The distribution of Te indicates reduced strength in the lower crust and lithospheric mantle beneath southern and central Greenland, which may be due to the passage of the Iceland hot spot during the last 100 Ma. In contrast, the northern part of Greenland shows a large Te, implying mechanical coupling between crust and uppermost mantle and suggesting the existence of a cold and strong tectonic unit. In a relative sense, the distribution of Te values is consistent with estimates of lithospheric thickness based on seismic velocity models, indicating a dominantly thermal control on lithospheric structure and evolution.

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Section: Introductionmentioning

confidence: 63%

Weakened Lithosphere Beneath Greenland Inferred From Effective Elastic Thickness: A Hot Spot Effect?

Steffen

Audet

Lund

2018

Geophysical Research Letters

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“…Jin et al () explained the Bouguer anomaly with a model of overlapping of Indian and Eurasian plates. However, regional tomography results indicate that the lateral heterogeneous Indian lithosphere extends to the IYS in western Tibet (Razi et al, ), to the BNS in central Tibet and to the JRS in eastern Tibet (Basuyau et al, ; Liang et al, ). These observations of the front of the Indian mantle lithosphere together with other different tomography results (Bijwaard & Spakman, ; Kind & Yuan, ; Li et al, ), as indicated by the two lines in Figure , do not match the geometry of the gravity low in the Lhasa terrane.…”

Section: Resultsmentioning

confidence: 99%

Detailed Configuration of the Underthrusting Indian Lithosphere Beneath Western Tibet Revealed by Receiver Function Images

Zhao

Yuan

et al. 2017

JGR Solid Earth

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We analyze the teleseismic waveform data recorded by 42 temporary stations from the Y2 and ANTILOPE‐1 arrays using the P and S receiver function techniques to investigate the lithospheric structure beneath western Tibet. The Moho is reliably identified as a prominent feature at depths of 55–82 km in the stacked traces and in depth migrated images. It has a concave shape and reaches the deepest location at about 80 km north of the Indus‐Yarlung suture (IYS). An intracrustal discontinuity is observed at ~55 km depth below the southern Lhasa terrane, which could represent the upper border of the eclogitized underthrusting Indian lower crust. Underthrusting of the Indian crust has been widely observed beneath the Lhasa terrane and correlates well with the Bouguer gravity low, suggesting that the gravity anomalies in the Lhasa terrane are induced by topography of the Moho. At ~20 km depth, a midcrustal low‐velocity zone (LVZ) is observed beneath the Tethyan Himalaya and southern Lhasa terrane, suggesting a layer of partial melts that decouples the thrust/fold deformation of the upper crust from the shortening and underthrusting in the lower crust. The Sp conversions at the lithosphere‐asthenosphere boundary (LAB) can be recognized at depths of 130–200 km, showing that the Indian lithospheric mantle is underthrusting with a ramp‐flat shape beneath southern Tibet and probably is detached from the lower crust immediately under the IYS. Our observations reconstruct the configuration of the underthrusting Indian lithosphere and indicate significant along strike variations.

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“…The value of our absolute P wave speed at the depth of 90 km is ∼8.4 km/s, which is appropriate for eclogite at this depth [ Huang et al ., ]. The presence of eclogite extending northward from the IYS in our study appears similar to the recent results from the Hi‐CLIMB project ∼100 km to the east of our study area [ Nabelek et al ., ; Basuyau et al ., ]. However, in our images the fast material extends farther north, and merges with a broader fast anomaly north of BNS.…”

Section: Discussionmentioning

confidence: 99%

“…Seismological studies of the crustal structure in the vicinity of western Tibet include a number of refraction lines [Zhang et al, 2011], receiver functions studies based on a Sino-French data set [Wittlinger et al, 2004], more recent investigations associated with the Hi-Climb project [Basuyau et al, 2013;Griffin et al, 2011;Nabelek et al, 2009], and analyses of dispersion of both ambient noise and ballistic surface waves [Rapine et al, 2003;Caldwell et al, 2009;Sun et al, 2010].…”

Section: Previous Studies In Western Tibetmentioning

confidence: 99%

Crustal and uppermost mantle structure beneath western Tibet using seismic traveltime tomography

Razi

Levin

Roecker

et al. 2014

Geochem Geophys Geosyst

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We study the elastic wave speed structure of the crust and the uppermost mantle in western Tibet using P wave and S wave arrival times from regional earthquakes recorded by a temporary seismic network. We relocate the earthquakes, and subsequently invert travel time residuals for 3-D distributions of wave speed. Resolution tests with a variety of input structures are used to verify the reliability of our results. The crust beneath western Tibet has low P wave speed (5.9-6.3 km/s) throughout its nearly 80 km thickness, with lower values in this range concentrated within the Lhasa block. Beneath the Himalaya wave speeds are higher. Southern and western limits of the slow material beneath the Tibetan Plateau correlate with the Karakoram fault, and dip beneath the plateau at 40 angle. We find no evidence of a subhorizontal low velocity zone in the crust. In the uppermost mantle, we find a long and narrow region of fast (up to 8.4 km/s) P wave speed extending from the Karakoram fault in NE direction, and crossing the Bangong-Nujiang suture. In a north-south cross section, the distribution of relatively fast P wave speed suggests a ramp-flat geometry consistent with India underthrusting the Tibetan Plateau at least as far as 32.5 N. A plausible interpretation of the upper mantle fast feature is the formation of eclogite from the mafic lower-crustal material of India after it is underthrust beneath Tibet. Notably, in western Tibet this process only takes place in a narrow region.

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Joint inversion of teleseismic and GOCE gravity data: application to the Himalayas

Cited by 30 publications

References 61 publications

Weakened Lithosphere Beneath Greenland Inferred From Effective Elastic Thickness: A Hot Spot Effect?

Weakened Lithosphere Beneath Greenland Inferred From Effective Elastic Thickness: A Hot Spot Effect?

Detailed Configuration of the Underthrusting Indian Lithosphere Beneath Western Tibet Revealed by Receiver Function Images

Crustal and uppermost mantle structure beneath western Tibet using seismic traveltime tomography

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