IMPLEMENTING SEISMIC MOHO DEPTHS IN GEOID COMPUTATION

Survey Review ◽  
2003 ◽  
Vol 37 (289) ◽  
pp. 235-245 ◽  
Author(s):  
Hussein Abd-Elmotaal
Keyword(s):  
Moho Depths ◽  
Geoid Computation

Xác định mặt Moho ở Miền Nam Việt Nam

2008 ◽  
Vol 30 (4) ◽  
pp. 403-409
Author(s):  
Đỗ Đăng Trình ◽  
Bùi Thị Ánh Phương ◽  
Đặng Văn Liệt
Keyword(s):  
Viet Nam ◽  
The South ◽  
Moho Depths

Moho depths in the south of Vietnam

The preserved plume conduits of the Caribbean Large Igneous Plateau and their relation with the Galápagos hotspot back to 90 Ma

2021 ◽  
Author(s):  
Angela Maria Gomez Garcia ◽  
Eline Le Breton ◽  
Magdalena Scheck-Wenderoth ◽  
Gaspar Monsalve ◽  
Denis Anikiev
Keyword(s):  
Reference Frames ◽  
Thermal Anomaly ◽  
Caribbean Region ◽  
Positive Density ◽  
South American ◽  
Kinematic Models ◽  
Tomographic Data ◽  
The Caribbean ◽  
Moho Depths ◽  
South American Continent

<p>Remnants of the Caribbean Large Igneous Plateau (C-LIP) are found as thickened zones of oceanic crust in the Caribbean Sea, that formed during strong pulses of magmatic activity around 90 Ma. Previous studies have proposed the Galápagos hotspot as the origin of the thermal anomaly responsible for the development of this igneous province. Particularly, geochemical signature relates accreted C-LIP fragments along northern South America with the well-known hotspot material.</p><p>In this research, we use 3D lithospheric-scale structural and density models of the Caribbean region, in which up-to-date geophysical datasets (i.e.: tomographic data, Moho depths, sedimentary thickness, and bathymetry) have been integrated. Based on the gravity residuals (modelled minus observed EIGEN6C-4 dataset), we reconstruct density heterogeneities both in the crust and the uppermost oceanic mantle (< 50km).</p><p>Our results suggest the presence of two positive mantle density anomalies in the Colombian and the Venezuelan basins, interpreted as the preserved plume material which migrated together with the Proto-Caribbean plate from the east Pacific. Such bodies have never been identified before, but a positive density trend is also observed in the mantle tomography, at least down to 75 km depth.</p><p>Using recently published regional plate kinematic models and absolute reference frames, we test the hypothesis of the C-LIP origin in the Galápagos hotspot. However, misfits of up to ~3000 km between the present hotspot location and the mantle anomalies, reconstructed back to 90 Ma, is observed, as other authors reported in the past.</p><p>Therefore, we discuss possible sources of error responsible for this offset and pose two possible interpretations: 1. The Galápagos hotspot migrated (~1200-3000 km) westward while the Proto-Caribbean moved to the northeast, or 2. The C-LIP was formed by a different plume, which – if considered fixed - would be nowadays located below the South American continent.</p>

scholarly journals Strength contrast between plagioclase and olivine at water-rich Moho depths

2010 ◽  
Vol 105 (5) ◽  
pp. 286-290
Author(s):  
Shintaro AZUMA ◽  
Ikuo KATAYAMA ◽  
Ken-ichi HIRAUCHI ◽  
Shigeru YAMASHITA
Keyword(s):  
Moho Depths

Evaluation of the latest GOCE GGMs in support of regional geoid modeling over Greece

2021 ◽  
Author(s):  
Georgios S. Vergos ◽  
Ilias N. Tziavos ◽  
Dimitrios A. Natsiopoulos ◽  
Elisavet G. Mamagiannou ◽  
Eleftherios A. Pitenis
Keyword(s):  
Maximum Degree ◽  
Gravity Data ◽  
Ground Truth ◽  
Satellite Gravity ◽  
Disturbing Potential ◽  
Geopotential Models ◽  
Potential Functionals ◽  
Geoid Computation ◽  
Goce Satellite

<p>In the frame of the GeoGravGOCE project, funded by the Hellenic Foundation for Research Innovation, GOCE Satellite Gravity Gradiometry (SGG) data are to be used for regional geoid and gravity field refinement as well as for potential determination in the frame of the International Height Reference Frame (IHRF). An inherent step in the geoid computation with either stochastic or spectral methods is the reduction of the related disturbing potential functionals within the well-known Remove-Compute-Restore (RCR) procedure. In this work we evaluate the latest, Release 6 (R6), satellite only and combined Global Geopotential Models (GGMs) which rely solely on GOCE and on land gravity data. The evaluation is performed over the established network of 1542 GPS/Levelling benchmarks over Greece mainland (BMs), which have been used in the past for the evaluation of GOCE GGMs. We employ the spectral enhancement approach, during which the GOCE-based GGMs are evaluated every one degree to the maximum degree of expansion coupled by EGM2008 and high-frequency RTM effects. This synthesis resolves wavelengths corresponding to maximum degree 216,000, hence the omission error is at the few mm-level. TIM-R6, DIR-R6, GOCO06s and XGM2019e are evaluated using EGM2008 residuals to the GPS/Levelling as the ground truth. From the results achieved, the optimal combination degree of a GOCE-only GGM augmented with EGM2008 is selected to be used in the sequel as reference field for the practical determination of the gravimetric geoid over Greece.</p>

scholarly journals Geodynamic and structural factors of porphyritic objects localization in Sikhote-Alin

2018 ◽  
Vol 56 ◽  
pp. 04020
Author(s):  
Viktor Nevstruyev ◽  
Olga Kozlova
Keyword(s):  
Porphyry Copper ◽  
Volcanic Belt ◽  
Structural Factors ◽  
Sikhote Alin ◽  
The Andes ◽  
Tectonic Disturbances ◽  
Pacific Slab ◽  
Moho Depths ◽  
Objects Localization

Ore bearing porphyritic systems of Sikhote-Alin form linear zones in Cretaceous volcanic belt. They are limited to zones of tectonic disturbances at Moho depths of 19-25 mi (30-40 km). Pacific slab lies at around 340 miles (548 km) below the volcanic belt, which matches the slab depth of porphyritic deposits formation belts in the Andes and Indonesia-Tonga region. Formation of porphyry copper systems is linked to the processes of metalliferous fluids intrusion at slab destruction areas near asthenosphere.

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