The study attempts to address the tectonic evolution of the Sirte Basin, The seismic work reveal that seven fault zones dominate the area, mostly are NW-SE trending, particularly in the north part, while further to the south a NE-SW trend is noticeable. The thickness variation of the sedimentary fill is extremely affected by these fault zones. The analysis of the tectonic subsidence curves reveals that the tectonic subsidence of the Sirte Basin caused by two rift phases. Initial syn-rift subsidence began in the mid-Cretaceous (~100Ma) and ended at ~84Ma and was followed by slow post-rift subsidence which continued until renewed rifting and rapid syn-rift subsidence at ~65Ma, this phase continued through the Paleocene–Eocene and ceased at ~40Ma, during which ~400–615m of subsidence occurred, after which a second phase of slow post-rift subsidence took place right up to the present. The maximum crustal stretching factor calculated is 1.226 (22.6%). Few numbers of sills intruded into the pre Upper Cretaceous stratigraphic unit probably during the Late Cretaceous rifting. The area dominated by three broad highs anomalies, and a wide depocentre extends NE-SW at the southern part. The study reveals a Moho depth ~26.6–35.8km, and basement depth ranges 4.5-9.5km.

Between 1981 and 1982 the Banjarmasin Quadrangle in South-East Kalimantan was mapped by the Geological Research and Development Centre, Bandung at the scale of 1 : 250,000. This thesis reports the results of a follow-up study to the mapping programme, which was directed towards determining the age, origin and tectonic evolution of the Pre-Tertiary rocks which form the Meratus Mountains in the eastern part of the Banjarmasin Sheet. The study consists of detailed field-mapping of Pre-Tertiary rocks in well exposed river sections at the scale of 1:10,000. Measured sections of sedimentary units were made and all structural features were recorded. A comprehensive collection of rock samples was made for laboratory studies. Thin sections were used to determine the composition and origin of sedimentary and igneous rocks. Macro-and microfossils have been examined to determine the depositional environments and the ages of the sedimentary units. From these studies the Pre-Tertiary rocks are divided into a number of tectonostratigraphic units, whose age, origin, structural and tectonic evolution has been determined as far as possible. This information has been used to compile a synthesis of the tectonic development of the Meratus Mountains in the context of plate tectonics and the development of the western Indonesian region. Isotopic and palaeontological dating has shown that the units exposed in the Meratus Mountains range in age from Early Cretaceous to Early Palaeocene. The oldest unit is the Paniungan Formation of Berriasian to Barremian age. It grades upward into the Upper Barremian to Lower Aptian Batununggal Formation. These formations are interpreted as shelf to slope sediments. It is suggested that shortly after deposition, most parts of the shelf to slope sediments were juxtaposed by strike-slip faulting with oceanic crust now represented by the Meratus Ophiolite Complex. Subduction generated a calcalkaline volcanic arc which then collided with the Sunda continent in the Cenomanian time. This collision zone was disrupted and sliced by strike-slip faults, forming a pull-apart basin within it. The absence of Palaeocene to Lower Eocene deposits reflects uplift, subsequently followed by rifting, regional subsidence and deposition of an Eocene-Miocene transgressive sequence. The present configuration of the Meratus Mountains resulted from late Middle Miocene and Plio-Pleistocene tectonic events.

The structural evolution of the Barmer Basin and the context of the rift within the northwest Indian region are poorly understood, despite being a prolific hydrocarbon province. In this work an integrated basin analysis is presented covering the outcrop-, seismic-, and lithosphere-scales. The early-stage structural evolution and the origin of poorly understood structural complications in the Barmer Basin subsurface are assessed. Subsequently, the findings are placed within the wider context of the northwest Indian region and the implications for continued hydrocarbon exploration within the Barmer Basin are discussed. Two non-coaxial extensional structural regimes are exposed at outcrop. Rift-perpendicular (≈ northeast-southwest) extension is demonstrably Paleocene in age and corresponded to the main episode of rifting in the Barmer Basin. A previously unrecognised, rift-oblique (≈ northwest-southeast) extensional event is poorly age constrained, and is suggested to have occurred during the Lower Cretaceous Epoch. Expansion of the investigation into the subsurface substantiates that rift-oblique extension preceded rift-perpendicular extension. The present day structural architecture of the Barmer Basin, therefore, resulted from the superimposition of two non-coaxial rifting events. Further structural analyses and lithosphere-scale forward modelling demonstrate that structural complications in the Barmer Basin subsurface arise from structural inheritance, and lithosphere flexure may have been substantial during Paleogene rifting. The results demonstrate active rifting throughout northwest India prior to the Cretaceous-Paleogene boundary and eruption of the Deccan Traps. Lower Cretaceous (northwest-southeast) extension within the Barmer Basin may be an intra-continental manifestation of transtension between the Greater Indian and Madagascan continents during Gondwana fragmentation. Subsequently, relocation of the plate boundary between the Greater Indian and African continents in the wake of the rapidly migrating Greater Indian continent initiated northeast-southwest extension. Mesozoic sub-basins and the improved understanding of structural geometries with proven trapping potential are important considerations for ongoing hydrocarbon exploration within the Barmer Basin.

Normal fault systems within incipient rifts comprise an array of small-scale structures, including networks of fractures and small displacement faults (<15 m) that represent the incremental strains that develop during rift propagation. To constrain the evolution of volcanic rift systems, I investigate rift-fault propagation and localisation at a range of scales using laboratory-based mechanical characterisation of host rocks, and high-resolution structural mapping of faults, and fault-related deformation in an incipient (Koa’e fault system, Hawai’i), and evolved (Krafla fissure swarm, Iceland) rift system. Experimental analysis of pahoehoe lava from Kilauea’s south flank, Hawai’i, highlight a distinctive physical and mechanical stratigraphy related to the volume, and geometry, of voids within the lava. The resulting variability in intact strength produces the effect of a multi-layered sequence within a single lava, and will exert significant control on the segmentation and linkage of initial cracks (mm-scale or less) that develop. High- resolution mapping of the distribution, geometry, and kinematics of cm- to km-scale extensional strains in the Koa’e fault system (Hawai’i) and the Krafla fissure swarm (Iceland) also reveals evidence for segmented fault propagation, linkage and non-coaxial strain. This segmentation is a function of the varying natural mechanical anisotropy of the deforming sequence and non-uniform strain rates. Results from the Koa’e and Krafla rifts are compared with break-up related deformation from the NE Atlantic margins to model the evolution of non-coaxial fault sets at the margin scale. Fault and intrusion data from the Faroe Islands and East Greenland highlights geometrically and kinematically comparable structural sets, implying an analogous kinematic evolution of inter-rift strains. I infer that stress transfer during NE Atlantic opening took place by sub-basin scale ancillary faults and dikes, associated with two overlapping, active rift systems in the Paleogene – a NE-propagating Reykjanes ridge, and a SW-propagating Aegir ridge – rather than via transfer fault segmentation.

The application of 3D seismic data to the study of fault evolution has greatly increased our understanding of how normal and thrust faults propagate. Specifically, by combining displacement distribution plots and a thorough analysis of the fault geometry, we can determine: linkage history, restrictions to fault growth, and blind versus emergent propagation. However, these methods have never been applied to strike-slip faults in seismic data due to the difficulty in imaging kinematic indicators or piercing points that quantify displacement. This thesis presents a novel technique that allows for the rapid identification of kinematic indicators in two 3D seismic datasets from the Levant Basin, Eastern Mediterranean, which enables the displacement distribution of strike-slip faults to be analysed beyond what has been accomplished by traditional field-based studies. The high quality of the data also enables the detailed investigation into the 3D geometry of strike-slip faults to be used in conjunction with the displacement data to better understand the upward vertical propagation history. Results indicate that high displacement faults show distinctly different geometries from low displacement faults, and that strain rate and propagation mode may be integral in controlling geometry type. Furthermore, the geometry of the naturally occurring examples presented here, shows distinct differences from analogue studies, and suggests future work should be applied to understanding what controls these discrepancies. The displacement distribution also allowed insight into fault network relationships at the regional scale, in addition to individual faults. In particular, the 3D geometry of conjugate intersections, branching intersections, and tip structures was explored. The results yielded very complex and confounding structural relationships, which suggest that deformation is rarely as simple as 2D interpretations show, and thus may have significant consequences to precious resource extraction.

Polygonal faults are layer-bound arrays of normal faults confined to specific stratigraphic intervals called tiers. Typically hosted in fine-grained sediments, polygonal faults are thought to have the potential for fluid leakage and represent a potential seal bypass mechanism. Intergral to understanding the impact of polygonal faults on regional top seal is timing and evolution of polygonal fault tiers. Whilst there are numerous studies imaging and describing polygonal faults in numerous basins around the world, very few specifically consider the growth of polygonal faults. Additionally, very few polygonal fault studies examine the evolution of fault hierarchies and how these hierarchies accommodate strain and deformation within the tier. This study examines two wedge-shaped polygonal fault tiers on different passive margins. The first polygonal fault tier studied is from offshore Angola and is hosted in sediment thickness of less 500 m, in Plio-Pleistocene claystones. The second tier examined is from the Modgunn Arch, Norwegian Margin and is hosted in a sequence of siliceous oozes and claystones of Eocene to Pliocene age, up to 1200 m in thickness. This study uses the differences in sediment ages to compare and contrast polygonal fault tiers at different stages of evolution and aims to examine common features between young and mature tiers in order to constrain tier evolution. This study considers two aspects of polygonal fault growth. Firstly it considers the utility of perturbations in polygonal fault tiers around features of the base of the tier. These perturbations have the potential to be a useful proxy for elucidating the nucleation position of polygonal faults in the tier. The second aspect of polygonal fault tier evolution reviews the mechanisms that control organisation hierarchies within a tier and examines the role of linkage in creating large master polygonal faults. The results of this thesis show that the polygonal faults can initiate at low temperatures and low pressures, in sediment thickness of 100 m or less. Moreover, it can be demonstrated that polygonal fault tips propagate preferentially upwards with basal tips pinned by a mechanical boundary at the base of the tier and lateral tips pinned by early forming branchline intersections. The transition from shallow to deep burial shows that polygonal fault hierarchies are naturally forming and may relate to variation in the propagation rate of polygonal faults within the tier. With increasing burial, there 3 is an increased likelihood of branchline interaction. Branchline interaction can occur laterally with lateral tips abutting against other faults in the network. Vertical abutments occur where upwardly propagating tips interact to form triangular abutments and are a key mechanism forcing in the organisation of polygonal faults and growth of Master faults. Both abutment styles also impact the spatial distribution of displacement maxima. Polygonal fault tiers also show subtle spatial variablilty in orientation and linkage mechanisms that can be attributed to the distribution and magnitude of far field stresses as well as the early fault dimensions. This thesis also presents a primie facie case for diachronaity in polygonal fault growth driven by variations in sediment loading and branchline linkage complexity. Overall, this thesis describes and accounts for some key behaviours of incipient polygonal faults tiers.

Fault zone properties at depth are often inferred from seismic properties such as seismic velocities and attenuation. An understanding of how fault zone properties and processes influence seismic measurements is required for successful interpretations to be made. As fault zones are heavily fractured and often fluid-rich areas, a knowledge of the influences of cracking and fluid content on seismic measurements is needed. This will allow better interpretation of fault zone properties and how they may change at the time of an earthquake. Research presented in this thesis is concentrated on two regions of strike-slip faulting: the Parkfield area of the San Andreas fault and the exhumed Carboneras fault zone region of SE Spain. Well-preserved exhumed faults allow observation of fault structure at seismogenic depths. The structure of the exhumed Carboneras fault has previously been suggested as an analogue for the Parkfield area at depth. Laboratory measurements can help us to determine what processes occur at seismogenic depths in active faults. They can also aid in interpretation of seismic studies. In this thesis laboratory and seismic studies are brought together in order to gain a greater understanding of fault zone seismic properties at depth and how to interpret them. In order to characterise the properties of the Carboneras fault, laboratory experiments of velocities through fault gouge and fault zone rocks are performed. The influences of fracture damage and local geological fabric on velocities are investigated. Gouge velocities are measured to be less than those of the mica schist rock through which the fault cuts. Velocity changes due to variations in crack damage in cyclic loading experiments are less than 5% of the original rock velocity. Strong velocity anisotropy is observed in the mica schist, with velocities of the order of 30% less when measured perpendicular to the strong foliation present in the rock. The consequences in terms of seismically imaging the fault zone are discussed. The effects of this strong velocity anisotropy need to be considered for specific source-receiver geometries and the local geological fabric in the locations of seismic experiments. Surface wave tomography and ambient noise analysis of the Carboneras fault zone region shows that faults are imaged as low velocity features at depth. Results suggest that velocities are reduced by approximately 10% at depths close to 3 km. The strong anisotropy observed in laboratory experiments of mica schist may also have implications for seismic imaging of this region as this rock crops out widely. This is discussed in terms of a potentially strong crustal component to shear-wave splitting observations in the region. In the second part of the thesis, temporal changes in seismic attenuation at the time of the 2004 M6.0 Parkfield earthquake are investigated. Seismic attenuation can give indications of fracture damage and healing. Spectral ratios between earthquakes within repeating clusters are calculated. A sharp increase in attenuation is observed immediately after the earthquake, which then decays over the next 2 years. The postseismic decay is fit by a logarithmic function. The timescale of the decay is found to be similar to that in GPS data and ambient seismic noise velocities following the 2004 M6.0 Parkfield earthquake. The amplitude of the attenuation change corresponds to a decrease of approximately 10% in QP at the time of the earthquake. The greatest changes are recorded to the northeast of the fault trace, consistent with preferential damage in the extensional quadrant behind a north-westerly propagating rupture tip. Our analysis suggests that significant changes in seismic attenuation and hence fracture dilatancy during co-seismic rupture are limited to depths of less than about 5 km.

Dans le Bassin Tyrrhénien Occidental, le rifting de la Marge Est-Sarde a eu lieu à partir du Miocène moyen-supérieur, par extension arrière-arc liée à la migration vers l’Est du système de subduction Apennin. Le Bassin Tyrrhénien Occidental a aussi été marqué par la Crise de Salinité Messinienne (CSM), à l’origine du dépôt de séries évaporitiques, dont localement une épaisse couche de sel mobile. À partir de l'interprétation des nouvelles données sismiques METYSS (Messinian Event in the TYrrhenian from Seismic Study), les objectifs de cette thèse consistent notamment à comprendre les modalités de la CSM, à préciser les relations entre tectoniques crustale et salifère et à contraindre l’évolution géodynamique de la Marge Est-Sarde. Les résultats de cette étude ont abouti à la cartographie détaillée des marqueurs de la CSM (unités de dépôts et surfaces remarquables), qui fournissent de bons indicateurs spatio-temporels. Ces marqueurs ont permis de contraindre l’analyse structurale qui révèle que la phase majeure d’activité crustale est pré-CSM. Le rifting de la marge est donc clairement pré-CSM et ne se prolonge pas jusqu’au Pliocène, comme cela avait été envisagé antérieurement. De plus, cette étude a mis en évidence des mouvements crustaux post-CSM bien distincts du rifting, liés à une phase de réactivation post-rift significative sur cette marge. Cette réactivation est complexe et diversifiée ; elle se manifeste non seulement par la réactivation en extension de failles nées du rifting, mais aussi localement par le développement de structures compressives et des basculements de socle, illustrant un couplage entre tectonique crustale et tectonique salifère. / In the Western Tyrrhenian Basin, rifting of the Eastern-Sardinian margin started during the middle to late In the Western Tyrrhenian Basin, rifting of the Eastern-Sardinian margin started during the middle to late Miocene times, due to back-arc extension following the eastward migration of the Apennine subduction system. The Western Tyrrhenian Basin has also been affected by the Messinian Salinity Crisis (MSC), which generated evaporitic deposits, particularly a thick mobile salt layer. Based on the interpretation of the new METYSS seismic data (Messinian Event in the TYrrhenian from Seismic Study), this work aims at a better understanding the modalities of the MSC, the relationships between crustal tectonics and salt tectonics, and the geodynamic evolution of the Eastern-Sardinian margin.The results lead to a detailed map of the MSC seismic markers (depositional units and remarkable surfaces). These markers provide spatiotemporal indicators and allow to constrain the structural analysis. Along the margin the major crustal stage is pre-MSC. Thus rifting of the margin occurred before the MSC and did not continue until Pliocene times, as previously considered. Moreover, this study evidences post-MSC crustal motions, well distinct from the rifting stage and linked to post-rift reactivation of the margin. This second crustal stage is various and complex; it reactivated crustal normal fault that had formed during rifting, but also generated crustal compressional structures. In some places, tilting of the pre-MSC basement triggered some salt tectonics.

Σκοπός της παρούσας διπλωματικής εργασίας είναι ποσοτική-ποιοτική ανάλυση των παραμορφωτικών επεισοδίων στο κάλυμμα των κυανοσχιστολίθων της Αττικο-κυκλαδικής μάζας. Βασίστηκε σε δεκαήμερη υπαίθρια εργασία που πραγματοποιήθηκε το Σεπτέμβριο του 2011 στο νησί της Άνδρου και συγκεκριμένα στο ΒΑ τμήμα του νησιού, όπου επικρατούν λιθολογίες μεταμορφωμένων πετρωμάτων υψηλών πιέσεων που δομούν το κάλυμμα των κυανοσχιστολίθων της Αττικοκυκλαδικής μάζας. Θεματικοί πυρήνες της εργασίας αυτής αποτέλεσαν η χαρτογράφηση των κύριων λιθολογιών που επικρατούν στην περιοχή και η τεκτονική-γεωμετρική ανάλυση των βασικών δομών παραμόρφωσης, που προέκυψε από τα δεδομένα που ληφθείσαν στην ύπαιθρο. Από τη χαρτογράφηση που πραγματοποιήθηκε προέκυψε ένας νέος γεωλογικός χάρτης του ΒΔ τμήματος της Άνδρου που αναφέρεται κυρίως στην ανώτερη δομική ενότητα του νησιού. Η τεκτονική-γεωμετρική ανάλυση περιελάμβανε μέτρηση του προσανατολισμού των επίπεδων καθώς και γραμμικών στοιχείων των δομών που προέκυψαν από τα ποικίλα παραμορφωτικά επεισόδια. / The purpose of this diploma is the qualititave-quantitave analysis of deformation phases in the Blueschsist nappe of Attico-cycladic massif

Rifted continental margins and extensional basins, provide lasting records of the processes that occur during continental break-up and initial spreading. The eastern Black Sea (EBS) basin provides a good setting to study the development of continental margins, because of ongoing sedimentation during its development and the close proximity of its conjugate margins. Here, I present an analysis of a new wide-angle seismic dataset that reveals the structure of the deep sediments, crust and upper mantle within the EBS basin. These data provide a unique look at the formation of extensional basins, as the dataset includes a prole that is orientated parallel to the rift axis. This prole places new constraints on the variation in magmatism that accompanied continental rifting and the lateral extent over which these variations occur. The wide-angle data show 8-9km of sediment in the centre of the basin, and reveal a wide-spread low-velocity zone (LVZ) within the deep sediments. The depth of this LVZ coincides with the organic-rich mud layer identied as the Maikop, and indicates overpressure within this formation. From the seismic velocity model, excess pore pressures of 60 - 70 MPa above hydrostatic were estimated within the Maikop. The wide-angle data also reveal highly thinned continental crust (7km thick) in the western EBS, and crust interpreted as thick oceanic crust (13km thick) in the eastern EBS, implying a transition from magma-starved to magmatically robust rifting. Lateral variations in mantle temperature and composition can account for a gradual increase in magmatism, but the wide-angle data reveal that this transition is abrupt (30km) and coincides with one of a series of basement scarps. These results impact the interpretations of other rift zones, where a variation in the syn-rift magmatism is observed, but the nature of the transition is not known.