Depth-Recursive Tomography of the Bohemian Massif at the CEL09 Transect—Part B: Interpretation

Novotný, Miroslav

doi:10.1007/s10712-011-9155-x

Cited by 9 publications

(6 citation statements)

References 71 publications

(108 reference statements)

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“…We will be perform such extended comparison with the 9HR density model derived by Š vancara and Chlupáčová (1997)-see fig. 4 in Part B (Novotný 2012). It will be shown that the 6,100 ms -1 isovelocity of the DRTG image tightly correlates with the density interface of mafic intrusion in a length over 50 km.…”

Section: Comparison With Previous Tomographic Resultsmentioning

confidence: 84%

Depth-Recursive Tomography of the Bohemian Massif at the CEL09 Transect—Part A: Resolution Estimates and Deblurring Aspects

Novotný

2011

Surv Geophys

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The refraction CEL09 profile from the CELEBRATION 2000 project intersects the main terranes of the Bohemian Massif in the NW-SE direction: the Saxothuringian, the Teplá-Barrandian, the Moldanubian and the Moravo-Silesian. In its easternmost part, it crosses the Western Outer Carpathians overthrust westward onto the Bohemian Massif. Only the first 450 km were surveyed with the densest deployment of shot points providing data suitable for a reliable geological interpretation. The first-arrival depth-recursive tomography was applied here to derive a P-wave velocity image of the upper and middle crust (Part A). The proper interpretation of the obtained velocity features is the subject of the accompanying paper (Part B). The attained resolution in the velocity image is shown to be superior as compared with the previous CEL09 models based also on the more uncertain later arrivals of reflection waves. The applied DRTG (depth-recursive tomography on grid) method is based on a regular network of refraction grid rays generated for iteratively updated starting models. Only the distinct first arrivals with minimum uncertainty are used for the DRTG inversions to yield the maximum resolution. Thanks to the full control of the data fit by the grid rays used, the statistical lateral resolution could be determined at single grid depths for the chosen confidence levels. Thus, the lateral sizes of the anomalies that can be yet resolved are determined in dependence on their depths and their velocity excesses. The defocusing of the imaged features is studied on the basis of the spatial responses to spike excitation. The calculated spatial responses also allowed the edge smearing of the velocity anomalies to be assessed. Special attention is paid to the imaging of low-velocity zones that are usually suppressed by the smoothing measures used in standard tomographic methods. An improvement was achieved if the smoothing was suggested with regard to the occurrence of the low-velocity zones repeatedly appearing in higher iterations. The gained deblurring effect concerns both the negative and positive anomalies as documented on the velocity features interpreted in the accompanying paper.

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Section: Comparison With Previous Tomographic Resultsmentioning

confidence: 84%

Depth-Recursive Tomography of the Bohemian Massif at the CEL09 Transect—Part A: Resolution Estimates and Deblurring Aspects

Novotný

2011

Surv Geophys

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“…If it exaggerates the travel-time residuals after tomo- Fig. 12 The P-wave velocities and Bouguer anomalies along the CEL09 profile (Novotný 2012). The model fits the travel times at the marked grid nodes with an overall RMS of 97 ms (Novotný 2011).…”

Section: Interpreting the Velocity Patternsmentioning

confidence: 98%

“…The derived velocity image revealed the subduction features which remained previously unresolved by the ray-tracing modeling of Hrubcová et al (2005) and also by the non-iterative method of Růžek et al (2007). The CEL09 velocity section particularly imaged the mafic intrusions shaped by the inclined slab of Saxothuringian crust subducted beneath the TBU (Novotný 2012).…”

Section: Previous Seismic Investigationsmentioning

confidence: 99%

“…The CEL09 section revealed the subduction features due to the SXT slab underthrusting the TBU and Central Bohemian Shear Zone (CBSZ) -see Novotný (2011Novotný ( , 2012 for details. Figure 12 presents the SE part of the SXT slab detachment surface plunging beneath the CBSZ and Central Bohemian Plutonic Complex (CBPC).…”

Section: The Transverse Sections Along S04 and Cel09 Profilesmentioning

confidence: 99%

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Felsic diapirism beneath the high-grade terrains in the eastern Bohemian Massif - refraction tomography evidence

Novotný¹

2018

J. Geosci.

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Unlike standard ray-based tomographies, the Depth-Recursive Tomography on Grid (DRTG) method assesses the travel-time fit at each model grid node using a regular network of refraction rays. This concept allows estimating the lateral resolution achieved in the velocity image that regards the chosen confidence levels and the strength of velocity anomalies. Recently, The DRTG has been applied to the S01 and CEL09 refraction profiles imaging major crustal structures of the Bohemian Massif in enhanced resolution. Now, similar enhanced velocity models are derived along the S04, S02 and S03 profiles mapping the Sudetic and Moldanubian regions. The S02 and S03 and the transverse CEL09 and S04 velocity sections particularly imaged the subsurface of the Moldanubian high-grade belts to the 15-20 km depth. Their common interpretation revealed the signatures of exhumation processes from upper-mantle depths assumed in this region. Particularly, the S02 and S03 sections map large volumes of high-grade metamorphic rocks forming low-velocity (LV) diapirs that are surrounded by 7000-6400 m/s high-velocity (HV) elevations. The S03 section images the coupled HV-LV-HV anomalies beneath the high-grade complexes of the Orlica-Śnieżnik Dome (OSD) and the Góry-Sowie Unit (GSU). The central gradient-free LV (5800-6000 m/s) cores of these triplets apparently correspond to the OSD or GSU felsic granulites/gneisses that ascended to supra-crustal levels. The Bouguer anomaly map suggests that the S02 and S03 profiles intersect the felsic sheets formed along the transverse Sudetic faults. Along the western belt of Moldanubian high-grade rocks, the S02 section revealed an extensive HV body shallowly emplaced beneath the high-grade Gföhl and Ostrong assemblages. Three mid-crustal HV elevations, correlating with local magnetic anomalies, obviously represent the deep sources of this HV mafic body and indicate its autochthonous nature. Finally, the DRTG also detected a shallowly emplaced HV layer beneath the Saxonian Granulite Massif at the S04 section. The mid-crustal HV-LV-HV diapiric triplets and shallowly emplaced HV bodies are likely typical of the high-grade terrains. The observed patterns resulted from contemporaneous intrusion of mafic and, more viscous, felsic magmas during continental collision. The inferred structural features of subduction-exhumation processes are suggested to further constrain their thermo-mechanic modeling.

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“…This Přibyslav-Vitice fault zone represents NNE-SSW sinistral strike-slip fault marked by a zone of mylonitization [8]. It represents very important seismic zone [3] and geophysical boundary [5].…”

Section: Introduction mentioning

confidence: 99%

Directions of Valley Axes in Relationship to Geological Structure-Element Orientation in the Stříbrné Hory Area in the Bohemian-Moravian Uplands (Czech Republic)

Juráček¹,

Melichar²

2015

JGGE

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The purpose of this paper is to evaluate control of orientation of foliations and joints on the direction of valley axes in the Stříbrné Hory area in the Bohemian-Moravian Highlands in central part of the Czech Republic. This area is predominantly built by metamorphic rocks. It is situated near the Přibyslav deep-seated fault. The data concerning of foliations, joints and valley axes were statistically analyzed and then visually compared according to their distribution using direction roses. Directions of valley axes have generally orientation of NNE-SSW, SE, E−W, NW and WNW and coincide with the system of foliations and ordinarily steep joints.

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Depth-Recursive Tomography of the Bohemian Massif at the CEL09 Transect—Part B: Interpretation

Cited by 9 publications

References 71 publications

Depth-Recursive Tomography of the Bohemian Massif at the CEL09 Transect—Part A: Resolution Estimates and Deblurring Aspects

Depth-Recursive Tomography of the Bohemian Massif at the CEL09 Transect—Part A: Resolution Estimates and Deblurring Aspects

Felsic diapirism beneath the high-grade terrains in the eastern Bohemian Massif - refraction tomography evidence

Directions of Valley Axes in Relationship to Geological Structure-Element Orientation in the Stříbrné Hory Area in the Bohemian-Moravian Uplands (Czech Republic)

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