scholarly journals Crustal thinning from orogen to back‐arc basin: the structure of the Pannonian Basin region revealed by P‐to‐S converted seismic waves

2021 ◽  
Author(s):  
Dániel Kalmár ◽  
György Hetényi ◽  
Attila Balázs ◽  
István Bondár ◽  
Keyword(s):  
Seismic Waves ◽  
Pannonian Basin ◽  
Crustal Thinning ◽  
Back Arc ◽  
Basin Region

Reconnaissance seismic refraction-reflection surveys in northwestern New Mexico

1984 ◽  
Vol 74 (4) ◽  
pp. 1263-1274
Author(s):  
Lawrence H. Jaksha ◽  
David H. Evans
Keyword(s):  
New Mexico ◽  
Wave Velocity ◽  
Lower Crust ◽  
Seismic Waves ◽  
Seismic Refraction ◽  
Velocity Model ◽  
P Wave ◽  
Uppermost Mantle ◽  
P Wave Velocity ◽  
Crustal Thinning

Abstract A velocity model of the crust in northwestern New Mexico has been constructed from an interpretation of direct, refracted, and reflected seismic waves. The model suggests a sedimentary section about 3 km thick with an average P-wave velocity of 3.6 km/sec. The crystalline upper crust is 28 km thick and has a P-wave velocity of 6.1 km/sec. The lower crust below the Conrad discontinuity has an average P-wave velocity of about 7.0 km/sec and a thickness near 17 km. Some evidence suggests that velocity in both the upper and lower crust increases with depth. The P-wave velocity in the uppermost mantle is 7.95 ± 0.15 km/sec. The total crustal thickness near Farmington, New Mexico, is about 48 km (datum = 1.6 km above sea level), and there is evidence for crustal thinning to the southeast.

Gravity modelling of the lithosphere in the Eastern Alpine-Western Carpathian-Pannonian Basin region

1994 ◽  
Vol 231 (4) ◽  
pp. 215-235 ◽  
Author(s):  
Robert J. Lillie ◽  
Miroslav Bielik ◽  
Vladislav Babuška ◽  
Jaroslava Plomerová
Keyword(s):  
Pannonian Basin ◽  
Gravity Modelling ◽  
Basin Region

Improved geophysical image of the Carpathian-Pannonian Basin region

2010 ◽  
Vol 45 (3) ◽  
pp. 284-298 ◽  
Author(s):  
M. Bielik ◽  
Z. Alasonati-Tašárová ◽  
H. Zeyen ◽  
J. Dérerová ◽  
J. Afonso ◽  
...  
Keyword(s):  
Pannonian Basin ◽  
Basin Region

scholarly journals Robustness analysis in forward modelling gravity data in crustal/lithospheric studies

2011 ◽  
Vol 41 (4) ◽  
pp. 279-296
Author(s):  
Vladimír Pohánka ◽  
Peter Vajda ◽  
Miroslav Bielik ◽  
Jana Dérerová
Keyword(s):  
Pannonian Basin ◽  
Gravity Data ◽  
Robustness Analysis ◽  
Measured Data ◽  
Forward Modelling ◽  
Planar Boundary ◽  
Inversion Procedure ◽  
The Difference ◽  
Basin Region ◽  
Harmonic Inversion

Robustness analysis in forward modelling gravity data in crustal/lithospheric studies The robustness of the gravimetric forward modelling is investigated by applying the harmonic inversion procedure at the input which is the difference of the calculated and measured surface gravity. The gravity data are taken from two profiles in the Carpathian-Pannonian Basin region. The result of the inversion are density models obtained from the original two-layer models with various horizontal boundary depth and density contrast. The deformation of the originally planar boundary is the measure of the mismatch between calculated and measured data. The calculated deformation has reached up to tens of kilometers and thus the uncertainties in determining the geometry of disturbing bodies by the forward modelling are substantial.

scholarly journals On the anisotropy of seismic waves in the Carpathian region

2020 ◽  
Vol 196 ◽  
pp. 02021
Author(s):  
Eugenia Lyskova ◽  
Konstantin Sannikov
Keyword(s):  
Upper Mantle ◽  
Western Europe ◽  
Seismic Waves ◽  
Pannonian Basin ◽  
Anisotropy Coefficient ◽  
Low Velocity ◽  
Crust And Upper Mantle ◽  
Carpathian Region ◽  
Vrancea Zone ◽  
Eastern Carpathians

The anisotropy of seismic waves in the continental regions still belongs to the category of controversial issues, since its estimates in different areas show a different sign of the anisotropy coefficient. In contrast to studies of oceanic regions, where SH velocities always prevail over SV velocities, in the continental regions the relations between the velocities are very different. The explanation for this, first of all, is the difference in structure. The structure of the crust and upper mantle under the oceans is much more homogeneous in comparison with the structure of the continental regions. There are several approaches to the estimation of anisotropy. The most traditional method is to use the maximum amount of data separately for Love and Rayleigh waves to study the lateral distributions of SH- and SV-wave velocity, despite the fact that the density of the coverage by paths, and, consequently, the regions of best resolution can be of different shapes and sizes. It was decided to use this method as the first approximation in creating an anisotropic portrait of the Carpathian region. The Carpathian region was chosen as the object of study, since it contains interesting contrasting features: (1) the Pannonian Basin, which is characterized by a thin crust, a thinned lithosphere, and anomalously high values of the heat flux; (2) the Tornquist-Teisseyre zone, which is parallel to the strike of the Eastern Carpathians, and represents the contact zone of the Precambrian lithosphere of the EEP and the relatively young lithosphere of Western Europe. (3) The third feature is the Vrancea zone, one of the most active seismic zones in Europe. It is located in the junction of young tectonic structures: the Southern and Eastern Carpathians, the Transylvanian Depression and the Pre-Carpathian Depression. The results of the study confirm that the Tornquist-Teisseyre Zone divides the structures of the ancient East European Platform and orogenic zones of Western Europe: the upper mantle throughout EEP is characterized by high velocities, whereas velocities throughout WE are markedly lower. Low velocity anomalies prevail under Pannonian Basin which is characterized by anomalously high heat flow values. The distribution of the anisotropy coefficient demonstrates an extended layer of low values of the anisotropy coefficient at depths of 150-200 km. Above this layer, velocity distributions reveal the block structure of the lithosphere. The earthquake sources in the Vrancea zone fall into the transition zone from the highvelocity mantle under the EEP to the low-velocity mantle under the WE. Earthquakes do not occur below the revealed asthenospheric layer.

scholarly journals The Geon 14 arc-related mafic rocks from the central Grenville Province

2018 ◽  
Vol 55 (6) ◽  
pp. 545-570 ◽  
Author(s):  
Barun Maity ◽  
Aphrodite Indares
Keyword(s):  
Granulite Facies ◽  
Crustal Thickening ◽  
Grenville Province ◽  
Long Duration ◽  
Crustal Thinning ◽  
Isotopic Analyses ◽  
Southeastern Margin ◽  
Intermediate Unit ◽  
Arc Setting ◽  
Back Arc

The late Paleoproterozoic to Mesoproterozoic (ca. 1.7–1.2 Ga) evolution of the active southeastern margin of Laurentia terminated with the Grenvillian continental collision and the development of a large, hot, long-duration orogen at ca. 1.09–0.98 Ga. As a result, much of the hinterland of the Grenville Province consists of Paleoproterozoic and Mesoproterozoic rocks, mostly preserved as an imbricate stack of high-grade gneisses, that represent a potential repository of active-margin processes. This study presents geochronologic, geochemical, and isotopic analyses of two granulite-facies suites of ca. 1.45–1.40 Ga mafic tholeiites from the Canyon domain (Manicouagan area, central Grenville Province). One suite consists of 1439 +76/–68 Ma high-FeTi mafic sills with εNd values of –0.4 (TDM 2.57–2.72 Ga), indicate derivation from variably depleted to enriched MORB-type mantle sources, probably in an extensional back-arc setting, before intrusion in a ca. 1.5 Ga supracrustal metasedimentary sequence. The other, previously dated, 1410 ± 16 Ma Mafic to intermediate unit exhibits εNd values of 0.0 to +0.9 (TDM 2.02–2.25 Ga), and variably enriched MORB to arc geochemical signatures, for which formation in a transitional back-arc to arc setting is suggested. Integrated with published information, the new data support a model of a long-lived continental-margin arc and intermittent back-arc development on southeast Laurentia during the mid-Mesoproterozoic (ca. 1.5–1.4 Ga), in which repeated short periods of extension and crustal thinning in the back-arc or intra-arc regions were followed by compression and crustal thickening.

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