Migmatization and large-scale folding in the Orlica–Śnieżnik Dome, NE Bohemian Massif: Pressure–temperature–time–deformation constraints on Variscan terrane assembly

2014 ◽  
Vol 630 ◽  
pp. 54-74 ◽  
Author(s):  
Mirosław Jastrzębski ◽  
Wojciech Stawikowski ◽  
Bartosz Budzyń ◽  
Ryszard Orłowski
Keyword(s):  
Bohemian Massif ◽  
Large Scale ◽  
Time Deformation ◽  
Temperature Time

Terrane boundaries in the Bohemian Massif: Result of large-scale Variscan shearing

1990 ◽  
Vol 177 (1-3) ◽  
pp. 151-170 ◽  
Author(s):  
Ph. Matte ◽  
H. Maluski ◽  
P. Rajlich ◽  
W. Franke
Keyword(s):  
Bohemian Massif ◽  
Large Scale

Trans-lithospheric diapirism documented in the Variscan Bohemian Massif – comparison with numerical models

2020 ◽  
Author(s):  
Petra Maierová ◽  
Karel Schulmann ◽  
Pavla Štípská ◽  
Taras Gerya ◽  
Ondrej Lexa
Keyword(s):  
Bohemian Massif ◽  
Numerical Models ◽  
Typical Feature ◽  
Crustal Material ◽  
Plate Interface ◽  
Peak Metamorphism ◽  
Subducting Plate ◽  
Set Up ◽  
Parameter Values ◽  
Temperature Time

<p>In the easternmost part of the European Variscan collisional belt, the Bohemian Massif, strongly metamorphosed felsic rocks crop out at several locations in a current distance of up to several hundreds of kilometers from the supposed contact of the subducting and overriding plates. These rocks were interpreted to originate from the subducting plate (now the Saxothuringian domain), which means that the orogenic root (the Moldanubian domain) consists of rocks that originate from both upper and lower plate. More specifically, the root domain is composed of (U)HP granulites and orthogneiss, garnet peridotites, eclogites and ultra-potassic plutons that alternate with the less metamorphosed rocks of the upper plate.</p><p>Such a process of subduction and emplacement of the subducted crust into the upper plate is called relamination. In order to better constrain the dynamics of relamination, we set up a numerical thermal-mechanical model and compare the modeling results with the data from the Bohemian Massif. The model simulates oceanic and continental subduction and takes into account non-linear visco-plastic rheology, percolation of fluids, melting and melt extraction. For different parameter values, the models show different styles of behavior, namely (i) exhumation of the subducted crust along the plate interface, and (ii) flow of the subducted crust beneath the upper plate and then incorporation into its crust (i.e. relamination).</p><p>In the former case, the material records heterogeneous peak metamorphism sampling the conditions along the subduction zone, and cooling during decompression. Similar features are typical for the metamorphic complex in the Saxothuringian domain of the Bohemian Massif.</p><p>In the latter case, the typical feature is the development of diapirs that grow from the subducted continental crust, pierce the overlying lithosphere and intrude into the middle crust of the upper plate. We show that growth of such trans-lithospheric diapirs results in a similar rock assemblage as observed in the orogenic root in the Bohemian Massif. The pressure-temperature-time paths obtained in the modeled diapirs mimic those of the Moldanubian granulites. The flow of crustal material through the mantle wedge results into mixing, hydration of the mantle and melting of both materials. Emplacement of the resulting melt into crust can explain formation of the Moldanubian ultra-potassic plutons.</p>

Shear wave splitting as diagnostics of variable tectonic fabrics across the Eastern Alps – Bohemian Massif contact zone

2020 ◽  
Author(s):  
Luděk Vecsey ◽  
Jaroslava Plomerová ◽  
Vladislav Babuška ◽  
the AlpArray-EASI Working Group ◽  
the AlpArray Working Group
Keyword(s):  
Shear Wave ◽  
Bohemian Massif ◽  
Upper Mantle ◽  
Large Scale ◽  
Broad Band ◽  
Eastern Alps ◽  
Shear Wave Splitting ◽  
Splitting Methods ◽  
Mantle Lithosphere ◽  
Wave Splitting

<p>We examine lateral variations of shear-wave splitting evaluated from data recorded during the passive seismic experiments AlpArray-EASI (2014-2015) and AlpArray Seismic Network (2016-2019). The swath about 200 km broad and 540 km long along 13.3° E longitude was selected to study the large-scale anisotropy in the mantle lithosphere beneath the Bohemian Massif (BM) and the Eastern Alps. The region is covered by about 200 broad-band temporary and permanent stations.</p><p>The shear-wave splitting evaluation consists of several steps: it starts by automated identification and pre-processing of SKS waveforms, filtering and quality check. Then we analyse and, if needed, also correct seismic waveforms for seismometer mis-orientations of all stations used. To improve results of splitting analysis of signals distorted by noise, we carefully apply two splitting methods (eigenvalue, transverse energy). We stack splitting measurements for waves closely propagating within the upper mantle and include particle motion analysis. The modified version of the splitting methods (Vecsey et al., 2008) enables us to retrieve 3-D orientation of large-scale anisotropic structures in the mantle lithosphere and deformations within the sub-lithospheric part of the upper mantle.</p><p>Both the evaluated shear-wave splitting parameters and the particle motions are consistent within sub-regions of the Alpine and BM upper mantle and exhibit significant and often sudden lateral changes across the whole region. We relate such changes to sharply bounded anisotropic domains with uniform fossil fabrics in the mantle lithosphere.</p>

scholarly journals A Real-Time Deformation Monitoring Method for Large-Scale Structure Based on Relay Camera

2021 ◽  
Vol 2021 ◽  
pp. 1-10
Author(s):  
Chuan He ◽  
Lianxiong Liu ◽  
Changhua Hu
Keyword(s):  
Real Time ◽  
Large Scale ◽  
Large Scale Structure ◽  
Deformation Monitoring ◽  
Scale Structure ◽  
Monitoring Method ◽  
The Real ◽  
Intrinsic Parameters ◽  
Time Deformation ◽  
Extrinsic Parameters

In the process of the deformation monitoring for large-scale structure, the mobile vision method is often used. However, most of the existent researches rarely consider the real-time property and the variation of the intrinsic parameters. This paper proposes a real-time deformation monitoring method for the large-scale structure based on a relay camera. First, we achieve the real-time pose-position relationship by using the relay camera and the coded mark points whose coordinates are known. The real-time extrinsic parameters of the measuring camera are then solved according to the constraint relationship between the relay camera and the measuring camera. Second, the real-time intrinsic parameters of the measuring camera are calculated based on the real-time constraint relationship among the extrinsic parameters, the intrinsic parameters, and the fundamental matrix. Finally, the coordinates of the noncoded measured mark points, which are affixed to the surface of the structure, are achieved. Experimental results show that the accuracy of the proposed method is higher than 1.8 mm. Besides, the proposed method also possesses the real-time and automation property.

scholarly journals Facile Synthesis of Template-Induced SnO2Nanotubes

2013 ◽  
Vol 2013 ◽  
pp. 1-6 ◽  
Author(s):  
Yang Liu ◽  
Yang Jiao ◽  
Fengyu Qu ◽  
Lihong Gong ◽  
Xiang Wu
Keyword(s):  
Electron Microscope ◽  
Large Scale ◽  
Average Diameter ◽  
X Ray Diffraction ◽  
Facile Hydrothermal Method ◽  
X Ray ◽  
Transmission Electron ◽  
Experimental Parameters ◽  
Mild Temperature ◽  
Temperature Time

Large scale SnO2nanotubes are successfully obtained by a facile hydrothermal method at a mild temperature. The morphologies and the microstructures of the as-synthesized SnO2products are characterized by scanning electron microscope (SEM) and transmission electron microscope (TEM). The average diameter of the nanotubes is about 100 nm. The phase and composition of the as-obtained products are investigated by X-ray diffraction (XRD). A series of comparison experiments were conducted by varying the experimental parameters, such as temperature, time, and the amount of the alkali, to study the formation mechanism of SnO2nanotubes.

scholarly journals Mantle lithosphere transition from the East European Craton to the Variscan Bohemian Massif imaged by shear-wave splitting

Solid Earth ◽  
2014 ◽  
Vol 5 (2) ◽  
pp. 779-792 ◽  
Author(s):  
L. Vecsey ◽  
J. Plomerová ◽  
V. Babuška
Keyword(s):  
Bohemian Massif ◽  
Large Scale ◽  
Structural Changes ◽  
Shear Waves ◽  
Transitional Zone ◽  
East European Craton ◽  
Anisotropic Structure ◽  
Mantle Lithosphere ◽  
East European ◽  
Back Azimuth

Abstract. We analyse splitting of teleseismic shear waves recorded during the PASSEQ passive experiment (2006–2008) focused on the upper mantle structure across and around the Trans-European Suture Zone (TESZ). Altogether 1009 pairs of the delay times of the slow split shear waves and orientations of the polarized fast shear waves exhibit lateral variations across the array, as well as back-azimuth dependences of measurements at individual stations. Variable components of the splitting parameters can be associated with fabrics of the mantle lithosphere of tectonic units. In comparison with a distinct regionalization of the splitting parameters in the Phanerozoic part of Europe that particularly in the Bohemian Massif (BM) correlate with the large-scale tectonics, variations of anisotropic parameters around the TESZ and in the East European Craton (EEC) are smooth and of a transitional character. No general and abrupt change in the splitting parameters (anisotropic structure) can be related to the Teisseyre–Tornquist Zone (TTZ), marking the edge of the Precambrian province on the surface. Instead, regional variations of anisotropic structure were found along the TESZ/TTZ. The coherence of anisotropic signals evaluated beneath the northern part of the Brunovistulian in the eastern rim of the BM and the pattern continuation to the NE towards the TTZ, support the idea of a common origin of the lithosphere micro-plates, most probably related to Baltica. Smooth changes in polarizations of the core-mantle boundary refracted shear waves (SKS), polarizations, or even a large number of null splits northward of the BM and further across the TESZ towards the EEC indicate less coherent fabrics and a transitional character of structural changes in the mantle beneath the surface trace of the TESZ/TTZ. The narrow and near-vertical TTZ in the crust does not seem to have a steep continuation in the mantle lithosphere. The mantle part of the TESZ, whose crust was formed by an assemblage of suspect terranes adjoining the EEC edge from the southwest, appears in our measurements of anisotropy as a relatively broad transitional zone in between the two lithospheric segments of different ages. We suggest a southwestward continuation of the Precambrian mantle lithosphere beneath the TESZ and the adjacent Phanerozoic part of Europe, probably as far as towards the Bohemian Massif.

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