Geochemistry and tectonic development of Cenozoic magmatism in the Carpathian–Pannonian region

This review considers the magmatic processes in the Carpathian–Pannonian Region (CPR) from Early Miocene to Recent times, as well as the contemporaneous magmatism at its southern boundary in the Dinaride and Balkans regions. This geodynamic system was controlled by the Cretaceous to Neogene subduction and collision of Africa with Eurasia, especially by Adria that generated the Alps to the north, the Dinaride–Hellenide belt to the east and caused extrusion, collision and inversion tectonics in the CPR. This long-lived subduction system supplied the mantle lithosphere with various subduction components. The CPR contains magmatic rocks of highly diverse compositions (calc-alkaline, K-alkalic, ultrapotassic and Na-alkalic), all generated in response to complex post-collisional tectonic processes. These processes formed extensional basins in response to an interplay of compression and extension within two microplates: ALCAPA and Tisza–Dacia. Competition between the different tectonic processes at both local and regional scales caused variations in the associated magmatism, mainly as a result of extension and differences in the rheological properties and composition of the lithosphere. Extension led to disintegration of the microplates that finally developed into two basin systems: the Pannonian and Transylvanian basins. The southern border of the CPR is edged by the Adria microplate via Sava and Vardar zones that acted as regional transcurrent tectonic areas during Miocene–Recent times. Major, trace element and isotopic data of post-Early Miocene magmatic rocks from the CPR suggest that subduction components were preserved in the lithospheric mantle after the Cretaceous–Miocene subduction and were reactivated especially by extensional tectonic processes that allowed uprise of the asthenosphere. Changes in the composition of the mantle through time support geodynamic scenarios of post-collision and extension processes linked to the evolution of the main blocks and their boundary relations. Weak lithospheric blocks (i.e. ALCAPA and western Tisza) generated the Pannonian basin and the adjacent Styrian, Transdanubian and Zărand basins which show high rates of vertical movement accompanied by a range of magmatic compositions. Strong lithospheric blocks (i.e. Dacia) were only marginally deformed, where strike–slip faulting was associated with magmatism and extension. At the boundary of Adria and Tisza–Dacia strike–slip tectonics and core complex extension were associated with small volume Miocene magmatism in narrow extensional sedimentary basins or granitoids in core-complex detachment systems along older suture zones (Sava and Vardar) accommodating the extension in the Pannonian basin and afterward Pliocene–Quaternary inversion. Magmas of various compositions appear to have acted as lubricants in a range of tectonic processes

Analyse der Schweredaten und interdisziplinaere 3D-Modellierung an einem Kontinentalrand (Chile, 36-42°S).

Titelblatt, Inhalt, Abstract und Zusammenfassung 1\. Introduction 2\. Geology 3\. Gravity Database 4\. Constraining Data 5\. Density Model 6\. Discussion 7\. Summary and Outlook References A. Additional Figures B. P/T Determination AcknowledgementsThis thesis was conducted as part of the research program Sonderforschungsbereich 267 (SFB 267) "Deformation Processes in the Andes". Over the last 12 years, the SFB 267 has focused on understanding of subduction-related processes. The Andean mountain belt is an orogen related to the subduction of the oceanic Nazca Plate below the western margin of the continental South American Plate. The Andes are characterized by significant variations in topography, crustal structure and deformation along the convergent margin. The southern working area of the SFB 267 (36-42°S) differers significantly from the previously studied, broad and high Central Andes at 20-25°S. The gravity data used for the modelling were measured during the past 30 years by several South American institutions. Part of the data used were measured and compiled by the gravity group of the SFB 267 (MIGRA 2000-2002 campaigns, subprojects C6 and F4). The analysis of the database, done in the framework of this thesis, revealed some serious problems among the compiled data. Due to these problems and a lack of information about the data, a resurvey of selected profiles was performed in 2002. After remeasurements, 500 erroneous stations were identified and excluded from the dataset and a reprocessed database for the study area was introduced. This database was then used to construct a 3D density model using the forward modelling technique. Within the gravity field, three forearc-arc segments have been identified. These segments are also evident in geology and are characterized by variations of the Bouguer gravity anomaly, especially along the coast. The northern segment at 36-39°S is characterized by a pronounced gravity high of 60-80×10-5m/s2. The middle segment at 39-40°S is characterized by a low gravity in the forearc (0×10-5m/s2 ) and the southernmost segment at 40-42°S is characterized by a forearc gravity high of 60×10-5m/s2 with a longitudinal offset compared to the northern segment. The density model is constrained by the seismic data in the northern segment at 36-39°S, whereas the results from the remaining segments are based only on geology and gravity data interpretation. The values of P-wave velocity from the four seismic profiles available in the study were converted into densities, which were then used during modelling. Also, two other approaches were used that allow calculating of P-wave velocity and density values of given rocks, based on their composition. The density determination was supplemented by direct density measurements of chosen samples representing the forearc region of the study area. Based on the results of the forward modelling, the variation within the gravity field along the margin is dominantly caused by regional features, such as the position of the subducting Nazca plate, as well as structures of the overlying continental plate. The structure of the oceanic plate (its position and density) appears to be crucial for the gravity field and hence, various tests were performed in order to show its influence and thus significance for the density modelling.Die vorliegende Dissertation wurde im Rahmen des Sonderforschungsbereichs 267 (SFB 267) "Deformationsprozesse in den Anden" durchgeführt. Seit 12 Jahren werden in diesem Schwerpunktprogramm subduktionsbezogene Prozesse und die Gebirgsbildung am aktiven Kontinentalrand Südamerikas in interdisziplinärer Weise untersucht und modelliert. Die Anden zeichnen sich durch starke laterale Variationen und strukturell-dynamische Segmentierung entlang des Kontinentalrandes aus. Es ist das Ziel dieser Arbeit, ein 3-dimensionales Dichtemodell für das südliche SFB-Untersuchungsgebiet zu erstellen und an Hand der übrigen Informationen und Daten zu interpretieren. Die Schweredaten, die hierbei verwendet wurden, sind über die letzten 30 Jahre von verschiedenen südamerikanischen Institutionen und der Arbeitsgruppe Gravimetrie im Rahmen des SFB 267 gemessen und kompiliert worden (MIGRA-Kampagnen 2000 und 2002 der SFB-Teilprojekte C6 und F4). Während der für diese Arbeit durchgeführten Analyse der gravimetrischen Datenbasis traten bei der Zusammenführung der Datensätze erhebliche Schwierigkeiten in Form von inkompatiblen Schwerewerten und offensichtlichen Mess- und Auswertefehlern auf. Hinzu kommt, dass keinerlei Metadaten für ein Re-Prozessing zur Verfügung standen. Aus diesen Gründen erfolgte 2002 entlang ausgewählter Profile eine Neuaufnahme von Schweredaten. Anhand dieser Messungen konnten 500 fehlerhafte Stationen identifiziert und der Datensatz homogenisiert werden. Dieser verbesserte Datensatz wurde als Grundlage für die Berechnungen des 3D-Dichtemodells mit Hilfe der Vorwärtsmodellierung verwendet. Bereits bei der numerischen Analyse der Schwereanomalien (Filtern, Feldfortsetzung, Felderseparation, Curvature, etc.) wurden drei Segmente identifiziert. Diese Segmente zeichnen sich besonders in Bereich der Küstenregion auch in den geologischen Strukturen und in Variationen der Bouguerschwere ab. Der nördliche Teil des Untersuchungsgebiets 36-39°S ist durch ein ausgeprägtes Schwerehoch von 60-80×10-5m/s2 im Forearc charakterisiert. Im Unterschied zum Rest des Arbeitsgebietes zeichnet sich das mittlere Segment zwischen 39-40°S durch ein verhältnismässig ausgeprägtes Schweretief im Forearc-Bereich (0×10-5m/s2) und der südlichste Teil des Untersuchungsgebiets 40-42°S ist durch ein Schwerehoch von 60×10-5m/s2 im Forearc-Bereich gekennzeichnet, das im Vergleich mit dem nördlichen Abschnitt eine Verschiebung nach Osten aufweist. Das 3D- Dichtemodell wird im nördlichen Segment durch Messungen anderer geophysikalischer Methoden gut gestützt, die beiden übrigen Segmente basieren allein auf der Interpretation von geologischen Befunden und Schweredaten. Die Werte der abgeleiteten P-Wellengeschwindigkeiten wurden in Dichten ürberführt und im Modell verarbeitet. Eigene Dichtemessungen an diversen Gesteinsproben vervollständigen die Dichteinformationen für die Modellierungen. Auf Grund der durchgeführten Dichtemodellrechnungen konnten die Variationen im Schwerefeld am Kontinentalrand erklärt werden. Dies trifft insbesondere auf regionale bzw. lokale Besonderheiten des Modellgebietes zu, wie z.B. die Tiefenlage und der Abtauchwinkel der subduzierten Nazca-Platte bzw. die Struktur und Dichte der darüber liegenden Kontinentalplatte. Der geometrische und kompositionelle Aufbau der ozeanischen Platte haben einen signifikanten Einfluss auf das gemessene Schwerefeld und aus diesem Grunde wurden verschiedene Tests zu alternativen Modellvarianten durchgeführt, um den dominierenden Einfluss der ozeanische Platte auf das Schwerefeld zu demonstrieren und diskutieren

Influence Of Twist On The Dynamic - Mechanical Yarn Properties

Cílem této diplomové práce bylo studium vlivu zákrutu příze na komplexní modul a jeho složky a na ztrátový úhel přízí při dynamickém namáhání s využitím dynamicko mechanické analýzy. Práce byla zaměřena na v praxi nejvíce využívanou syntetickou přízi, kterou je polyester. Rešeršní část se zabývá vlastnostmi vlákených materiálů v obecné rovině, dynamicko mechanickými vlastnostmi vlákených materiálů a popisem dynamicko mechanické analýzy. V experimentální části Byla vytvořena metodika měření komplexního modulu a jeho elastické a ztrátové složky, a také ztrátového úhlu, který je podílem ztrátové a elastické složky. Z výsledků vyplývá, že časová změna ztrátového úhlu a komplexního modulu i jeho složek je velmi malá. Byla nalezena závislost uvedených vlastností na zákrutu (zákrutovém koeficientu) a na frekvenci. Ztrátová složka komplexního modulu klesá se zákrutovým koeficientem a elastická složka stejně jako komplexní modul nejdříve roste a potom klesá. Ztrátový modul v závislosti na zákrutovém koeficientu klesá a potom mírně narůstá. Vyšší frekvence vede k vyšším hodnotám ztrátového úhlu. Dle práce Murayamy byl navržen parametr tření, který byl vypočten z hodnot ztrátového úhlu přízí a nezakrouceného vlákenného svazku při různých frekvencích. Bylo nalezeno, že tento parametr je lineární klesající funkcí zákrutového koeficientu. Navržený parametr tření koreluje především s faktorem orientace Pana, slabší korelace je s orientačním faktorem Whita i faktorem tření HearlaThe aim of this thesis was to study the effect of yarn twist on the complex module andits components and the yarn loss angle under dynamic stress using the dynamicmechanical analysis. The main focus of the thesis was on the synthetic yarn most sed inpraktice, i.e. polyester. The research part deals with the properties of fiber materials ingeneral, the dynamic mechanical properties of fiber materials and the description ofdynamic mechanical analysis. In the experimental part, the method for measuring thecomplex module and its loss and elastic component as well as the loss angle which isthe ratio of the loss and the elastic component. The results indicate that the time changeof the loss angle and the complex module and its components is very small. Adependence of said characteristics on the twist (i.e. twist coefficient) and the frequencywas found: the loss component of the complex module decreases with the twistcoefficient and the elastic component as well as the complex module itself initiallyincrease and then decrease. The loss module in dependence on the twist coefficientdecreases and then increases slightly. Higher frequencies lead to higher values of theloss angle. Following the work of Murayama a friction parameter was designed andcalculated based on the values of the yarn loss angle and untwisted fiber bundle lossangle at different frequencies. It has been found that this parameter is a lineardecreasing function of the twist coefficient. The suggested friction parameter correlatesmainly with the Pana orientation factor, there is a weaker correlation with thebenchmark White factor and the friction Hearle facto

The Lithospheric structure of the Western Carpathian-Pannonian Basin region based on the CELEBRATION 2000 seismic experiment and gravity modelling

The lithospheric structure of the Western Carpathian–Pannonian Basin region was studied using 3-D modelling of the Bouguer gravity anomaly constrained by seismic models and other geophysical data. The thermal structure and density distribution in the shallow upper mantle were also estimated using a combination of petrological, geophysical, and mineral physics information (LitMod). This approach is necessary if the more complicated structure of the Pannonian Basin is to be better constrained. As a result, we have constructed the first 3-D gravity model of the region that combines various geophysical datasets and is consistent with petrological data. The model provides improved estimates of both the density distribution within the lithosphere and the depth to major density discontinuities. We present new maps of the thickness of major sedimentary basins and of the depth to the Moho and the lithosphere–asthenosphere boundary. In our best-fitting model, the Pannonian Basin is characterised by extremely thin crust and lithospheric mantle, both of which have low density. A low-density uppermost asthenospheric mantle layer is also included at depths of 60–100 km. The Western Carpathians have only a thin crustal root and moderate densities. In contrast, the European Platform and Eastern Alps are characterised by lithosphere that is considerably thicker and denser. This inference is also supported by stripped gravity anomalies from which sediment, Moho and asthenospheric gravity contributions have been removed. These residual anomalies are characteristically low in the Western Carpathian–Pannonian Basin region, which suggests that both the ALCAPA and Tisza–Dacia microplates are ‘exotic terranes’ that are markedly different to the European Platform.16 page(s

Improved geophysical image of the Carpathian-Pannonian Basin region

Our paper presents the general overview of the current geophysical results, which helps to improve the geophysical image and the lithospheric structure of the Carpathian-Pannonian Basin region. Two different geophysical methods have been applied for the study of the structure and composition of the lithosphere as well as for determination of the lithospheric thermal structure. Firstly, integrated 2D modeling of gravity, geoid, topography and surface heat flow data was performed. Secondly, based on the results of the CELEBRATION 2000 seismic experiment, a large-scale 3D lithospheric gravity model was developed. The resulting map of the lithospheric thickness shows important variations in lithospheric thickness across the chain as well as along strike of the Carpathian arc. The sediment stripped gravity map is characterized by minima in the Eastern Alps and Western Carpathians. The maxima are observed in the Pannonian Back-arc Basin system, Bohemian Massif, Fore-Sudetic Monocline, Bruno-Silesian unit (BSU), Lublin Trough and partly in the Holy Cross Mts. and Malopolska unit. The Western Carpathian gravity minimum is a result of the interference of two main gravity effects. The first one comes from the lowdensity sediments of the Outer Western Carpathians and Carpathian Foredeep. The second one is due to the thick low-density upper and middle crust, reaching up to 25 km. The sediment stripped anomaly in the Pannonian Back-arc Basin system is characterized by gravity high that is a result of the gravity effect of the anomalously shallow Moho. The most dominant feature of the complete stripped gravity map is the abrupt change of the positive anomalies along the Pieniny Klippen Belt zone. The complete residual anomaly of the Pannonian Back-arc Basin system and the Western Carpathian orogen is characterized by a long-wavelength gravity low. The lowest values are associated with the thick low-density upper and middle crust of the Inner Western Carpathians. The European Platform is characterized by significantly denser crust with respect to the less dense crust of the microplates ALCAPA and Tisza-Dacia. That is why we suggest that the European platform represents consolidated, while the Carpathian-Pannonian Basin region un-consolidated crust