Understanding the behaviour of active continental scale fault zones at depth and how surface displacement is accommodated through the crust is important to improve understanding of large scale tectonics. Various studies on exhumed ductile shear zones have been carried out to investigate the processes that were active during deformation in the mid to lower-crust. This study adds to the growing knowledge by investigating processes recorded in the Uludağ Massif, NW Turkey. The Uludağ Massif and constituent faults provide an analogue for the mid-crust beneath the North Anatolian Fault (NAF) and forms part of a wider study incorporating geodesy and seismology. This study contributes to the wider project by providing a geological context to geodetic and seismological observations made using the DANA array over the NAF. In the first instance initial field observations are used to analyse the structural architecture of the shear zone to define the large scale structure and kinematics. Microstructures are observed and analysed to provide information on deformation kinematics, temperature, stress and strain rate for the exhumed shear zone. Techniques such as Electron Back Scatter Diffraction (EBSD) provide a data set from which crystal preferred orientation (CPO), CPO intensity and visco plastic self-consistency (VPSC) calibrations are used to consider how strain is distributed across shear zones. Concomitantly, Schmid factor analysis is used to ascertain active crystal slip systems in calcite across the shear zone related to strain localisation and effects such as strain hardening. Seismic properties are then calculated from the CPO to examine how different lithologies and structures within the Uludağ Massif affect the seismic properties using modelling techniques. Synthetic receiver functions are then created from these models and compared against the real seismic data and receiver functions from the DANA array on the NAF itself. Information on stress, shear strain, temperature and strain-rate build up a picture of localised deformation on strands including the Eskişehir and Bursa Faults over the shear zone on the scale of 100m – 10km. Thin section analysis and Schmid factor analysis show several weakening mechanisms are active along the Eskişehir Fault zone, whilst fault strengthening can be inferred within calcite deformation respectively. These observations have important implications for the contemporary seismogenic response if similar lithologies and structures comprise the current mid-crust beneath the NAF. However, the seismic properties of different lithologies and fabric orientations show little difference on the seismic response but the presence of a fault is obvious and could account for results of natural receiver function study via the DANA array.

The NE-SW trending Burdur-Acig?l-Baklan basin system of southwest Turkey represents the present-day configuration of a system initiated in late Miocene / early Pliocene times. During the Pliocene a half-graben, controlled by a NW-dipping planar fault system, developed in the area around Burdur. The Burdur Formation was deposited in this half-graben. Rapid subsidence is indicated by the lack of a well-developed footwall-sourced fan system. However, larger fans developed in the relay structures between en echelon fault segments. The centre of the basin was occupied by a deep saline lake. Orbitally-driven climatic change was the dominant control on sedimentation in this lake. The scarcity of wet-sediment deformation within the Burdur Formation suggests that levels of Pliocene seismicity were lower than twentieth century levels. Towards the end of the Pliocene the fault system controlling the Burdur basin became inactive and renewed faulting took place in the hangingwall of the old system. This event gave rise to the present-day configuration of narrow basins in the study area and was due to instability of the end-Pliocene topography. Both margins of the present-day Burdur, Acig?l and Baklan basins are faulted. In each case the major throw is on the fault on the southeast margin. A ? value of 1.18 calculated for the Burdur region assumes a planar fault geometry. As a curvature of up to 40 at depth cannot be ruled out this must be considered a minimum estimate. Each of the Burdur, Acig?l and Baklan basins is extending in a NW-SE direction (compared to the N-S extension direction of the Aegean). It is proposed that the basins are within a N-S trending deforming zone between the rapidly-extending Aegean region (to the west) and the relatively stable Anatolian plateau (to the east). The model adopted explains the clockwise rotation of fault-bounded blocks in the Burdur region. The dextral motion across the deforming zone, predicted by the model, may be a result of the anticlockwise rotation of western Turkey.

The Rhodope Massif of northern Greece and southern Bulgaria has been variably interpreted as a fragment of pre-Alpine, Hercynian or Precambrian continental crust, that was actively involved in European margin convergent tectonics during the Mesozoic and Tertiary. Alternatively it is proposed in this thesis that, for central Greek Rhodope, the lithological associations and tectonothermal history are consistent with progressive south-directed crustal growth through deep-level underplating, or subcretion, of material of oceanic and continental margin affinity, which was transferred from footwall to hanging wall within a north-directed Palaeotethyan subduction system. Central Greek Rhodope comprises a sequence of schists, gneisses and migmatites of wide compositional variation which have undergone intense tectonic intermixing. Extensive marble units occur in association with amphibolites, retrogressed eclogites, meta-gabbros and ultramafic rocks. These are intercalated with meta-sedimentary sequences, including quartzo-feldspathic gneisses, garnet and/or kyanite bearing mica schists and quartzites. The presence of slivers of pink marble and rare manganiferous and iron rich siliceous units is of significance. These various lithological components were underthrust northwards to deep crustal levels, subjected to high pressure (eclogite facies metamorphism) and underplated or subcreted to the base of the overriding Eurasian plate. The accretion event was characterised by a single phase of intense southwest-directed ductile thrusting accompanied by pervasive upper amphibolite facies metamorphism, migmatisation and intracrustal melt generation. Subsequent volcanic and plutonic activity occurred, and extensional tectonic exhumation brought the metamorphic complex up to its present position within the southern margin of Eurasia. This new interpretation may have interesting implications for other high grade terrains within convergent and collisional systems that have been assumed to represent ancient or pre-existing continental crust. If so, then the importance of deep level subduction-accretion as a mechanism of continental crustal growth has hitherto been underestimated.

The failure of plate tectonic theory to explain the deformation observed across continental plate boundary zones has led to the development of continuum models of lithospheric deformation in which the lithosphere is treated as a layer of viscous material governed by the equation for creeping viscous flow, where the left hand side represents spatial gradients of stress that are balanced by differences in gravitational potential energy on the right hand side. Strain rates and an assumed power law rheology are used as a proxy for stress, where <i>B</i> is a strength parameter that represents the depth-averaged temperature dependence of the lithospheric rheology, <i>E</i> is the second invariant of the strain rate tensor, and <i>n</i> is the power law exponent in the stress-strain rate relationship. Finite element methods are used to solve the thin viscous sheet equations (England & McKenzie, 1982), yielding a velocity field that may be compared to observations from regions of continental deformation. In this study I investigate the deformation of the lithosphere in two regions of active deformation: south-east Asia and the western North America plate boundary zone. Particular attention is paid to the degree to which the deformation fields reflect the driving forces, and the effect of lateral variations in effective viscosity and lithospheric strength upon the deformation field.

The mechanism by which crustal extrusion, or 'tectonic escape' functions remains poorly understood. Central Anatolia provides an example of extrusion where the kinematics of 'escape' - related strike-slip faults can be well-constrained. This study focuses on the Ecemis Fault Zone, one of the main strike-slip fault systems involved in the Cenozoic westward extrusion of Anatolia. This study concentrates on the structure, sedimentology, geomorphology and subsidence history of the EFZ, to constrain the timing and offset on this fault zone, and thereby build a more comprehensive model of extrusion of the context of the regional geology. Sedimentological data from Lutetian (Mid-Eocene) outcrops indicate that significant strike-slip occurred on the EFZ since the Mid-Eocene. Palaeocurrent and facies data establish that an inward-draining depocentre existed in the central EFZ during Late Oligocene - Early Miocene time, contemporaneously with regional crustal extension and unroofing of the nearby Nigde Core Complex. Sedimentological studies show that the present-day fault scarps of the EFZ were established during the latest Miocene - Early Pliocene, synchronous with the initiation of Anatolian extrusion. Subsidence curves indicate that the Late Oligocene - Early Miocene was a period of rapid subsidence rates in the Adana region (north of the Taurus Mountains) and that subsidence was more rapid in the EFZ area than in surrounding Cenozoic basins during this period. Rapid subsidence in the EFZ may have been associated with the formation of a pull-apart basin the location of the EFZ. Slikenline data analysis indicate that the EFZ was undergoing sinistral trans-tension by at least Mid-Miocene time, and that this changed to dominantly E-W extension during the Quaternary. Slikenline data from the Camardi area (northern EFZ) indicate that limited sinistral strike-slip has also occurred during the Quaternary, focused on a N-S striking small graben.

This study focuses on a Cretaceous Caribbean example of juvenile additions to the continental crust. The basaltic-tonalitic rock association studied is reminiscent of greenstone belts, which are believed to represent some of the earliest continental crust. The basaltic Aruba Lava Formation is part of the Cretaceous (predominantly 91 - 88 Ma) Caribbean oceanic plateau, which moved into the Caribbean region from the Pacific. The thick succession of submarine-to-emergent volcanic and sedimentary rocks on Aruba implies an intra-oceanic origin, and new petrographic, geochemical and isotopic data are all consistent with derivation of the Aruba Lava Formation from a mantle plume. Intrusion of a predominantly tonalitic batholith (dated as 85 - 82 Ma) occurred concurrently with deformation of the Aruba Lava Formation. The batholith is interpreted as having formed in response to the earliest stages of subduction beneath the plateau. This occurred subsequent to a subduction polarity reversal caused by the reluctance of the Caribbean oceanic plateau to be subducted. Subduction-derived mafic magmas, originating from the remnant mantle plume source region, were added to the plateau crust, where they triggered intracrustal partial melting and tonalite generation. This work demonstrates that rapid crustal growth can occur via accretion of oceanic plateaux: this mechanism does not require the presence of pre-existing crust, and may be analogous to the mechanism that generated the earliest continental nuclei. Addition of subduction-derived melts to the accreted material "ripens" the embryonic continent; this can happen within a few million years after the initial accretion event. Mantle plumes play an important part in transfer of mass and thermal energy from the mantle to the crust, and in reorganising tectonic plates. This allows reprocessing, remelting, and ripening of mantle-derived basalts to generate continental crust.

Faults can have significant impact on reservoir productivity. Understanding the factors that controls the fluid flow properties of fault rocks provides a sound basis to assess the impact of faults on reservoirs productivity. Therefore, different aspects that affect the fluid flow within siliciclastic fault formations were investigated in this research project. Fault rock samples from a number of locations were analysed including: (i) core samples from central and southern North Sea fields; (ii) and outcrop samples from the 90 Fathom fault, Northumberland, UK and Miri airport road exposure, Malaysia as well as the Hopeman fault from Invernesshire, UK. The impact of faults on fluid flow was assessed by integrating the data from QXRD analysis, microstructural examination, X-ray tomography, mercury porosimetry for pore size distribution, absolute and relative permeability measurements as well as capillary pressure tests. Single phase and multiphase flow properties which were conducted at a range of stresses are the most comprehensive collection of high quality fault rock data. The permeability measurements made using gas gave higher values than with brine, which in turn gave higher values that when measured using distilled water permeability. The differences in permeability could be the results of clay particles swelling; mobilisation and retaining within the confined pore throats, although these effects depend on the rock mineralogy and pore fluid composition. Moreover, the permeability stress sensitivity was investigated. The results showed that at low confining stresses the permeability of the fault rock core samples showed high sensitivity to stress, whereas at higher confining stresses the permeability was less pronounced to stress. This might be due to the core damage effects and the microfractures formed due to stress release, which were observed from SEM images. The pore radius calculated from gas slippage parameters at low confining pressures was in the same order of magnitude as the micro fracture width. The micro cracks could be easily closed due to stress increase hence resulted in reduction of permeability. Overall, the stress sensitivity of fault rocks from outcrop is less than that from core. This is consistent with the idea that stress sensitivity is mainly the result of the presence of grain boundary microfractures formed as core is brought to the surface. This indicates that permeability measurements made on outcrop samples may be more reliable. Another key finding was that the published permeability data (e.g. Fisher and Knipe, 2001) compared with present study data which is obtained at in-situ stress using formation compatible brines showed that the published data may not be inaccurate as the use of distilled water gives lower permeability than brines and low stresses resulted in higher permeability than in-situ stress measurements. Therefore, the results indicate that two different laboratory practices used in previous studies partially cancel each other out so that the existing data is yet valuable. The effective gas permeability were also measured at a range of stresses and it was observed that the samples with lower absolute permeabilities were more stress sensitive to stress than high permeable samples. The relative permeability results obtained were incorporated into a specific example of synthetic reservoir model. These suggested that faults formed within low permeability sands might act as a barrier to fluid flow.

In the past, fault seal analysis has been focused on extensional systems. How-ever, fault behaviour in terms of fault sealing is also critical within compressional thrust systems. The results of an evaluation of thrust fault evolution and hydro-carbon sealing behaviour in the Lenghu5 thrust belt of the Qaidam basin of NW China are reported. A multi-scale methodology, ranging from regional- to micro-scale, is utilized in this work to identify the detailed thrust fault architecture and its effect on hydrocarbon sealing properties. Regional-scale sections and 3D modelling are used to evaluate the evolution of faults within this thrust system and as a platform for detailed seal analysis. The results allow assessment of the timing of deformation, shortening and shorten-ing strain rate. Trishear models are used to assess deformation in the Lenghu5 thrust belt. Based on trishear propagation geometric models, the Lenghu5 de-formation history is simulated using forward trishear modelling. A range of trishear modelling parameters is used to interpret the various structural styles presented. This provides new insights to the potential application of trishear mechanism in complex natural structures developed in different environments. Meso-scale detailed structural maps of exceptionally well-exposed outcrops are used to extract information on local fault geometry. Main thrust faults, minor thrust faults and accommodation normal faults are all mapped in detail, making it possible to evaluate the differences of fault architectures between different types of faults. Models are proposed to define the elements of fault zones. Fault zone evolution models are constructed in order to understand the dynamic pro-cess of the fault development. Micro-structural analysis (e.g., SEM) of rock samples is used for assessment of the deformation mechanisms associated with fault zone development. The vital influence of micro-scale deformation mechanisms on hydrocarbon sealing properties has been evaluated, in order to reveal the relationship between the deformation mechanism and hydrocarbon sealing behaviour. This work illustrates the value of a regional- to micro-approach on thrust fault evolution and hydrocarbon sealing behaviour, and aims to identify the critical parameters that contribute to improving fault seal analysis in thrust systems.

The Carboniferous Central Pennine Basin provides an ideal testing ground to examine the effects of tectonic activity, climate variation, sea-level changes and evolving bathymetric conditions upon continental to marine strata. During deposition of the glacio-eustatically controlled Millstone Grit Group the bathymetry of the area changed, tectonic activity has been invoked to explain basin-margin unconformities and high frequency climate variations have been interpreted as a driver of small-scale cyclicity. Tectonic activity does not appear to have affected the stratigraphic character of the Millstone Grit Group significantly. The inference of a major tectonic unconformity on the northern margin of the Central Pennine Basin is re-interpreted through recognition of an incised valley. The influence of active tectonics is minor but tectonic lineaments provide loci for syn-depositional structural activity. Facies analysis of Gilbert-type deltas within incised valley fills indicates a highly variable flow regime. Contrastingly, Gilbert-type deltas during sea-level fall are formed under constant, low flow conditions. This difference is tentatively linked to variable monsoonal discharge. Bathymetric differences combined with sea-level variations strongly influence stratigraphic development. Shelf height is inferred as a control on valley incision based on analogue modelling, detailed field investigation of the oldest part, and literature review of the entire Millstone Grit Group. The deepest incised valleys occur where fluvial systems incised into the highest shelf margins. Analogue modelling indicates that deep incised valleys are associated with increased sediment supply to the slope relative to incised valleys formed on lower shelf margins during the same magnitude sea-level falls (in agreement with field data). Additionally, lateral variations in shelf-margin height appear to have steered the positions of fluvial systems, increasing the likelihood of valley incision in specific locations. Integrating basin depth and basin-margin morphology in sequence stratigraphic models as a controlling factor on the behaviour and position of fluvial systems might thus improve insight into the position and size of incised valley systems and associated turbidite lowstand fans.

The extensional Pannonian Basin is set within the convergent arc of the Alpine-Carpathian mountain system in central Europe. Various models have been proposed as mechanisms to drive extension within this collisional setting. As part of the Carpathian Basins Project(CBP), a temporary network of 56 broadband seismometers was deployed. With a further 44 permanent broadband seismometers, tomographic inversion of P and S-wave relative arrival-time residuals from teleseismic earthquakes, reveal the velocity structure of the mantle to a depth of 850 km throughout the Carpathian-Pannonian region. The tomographic models reduce the P-wave rms residual by 71% from 0.446 s to 0.130 s, and the S-wave rms residual by 59% from 1.513 s to 0.624 s. The effect of applying a deterministic crustal correction on the relative arrival-time residuals is tested using a crustal velocity model derived from previous crustal seismic experiments, but I show that the use of a station term parameter in the inversion provides a robust method of correcting for near-surface velocity variations in this experiment. At shallow sub-lithospheric depths several localised slower regions are imaged, which correlate with extensional depocentres and regional volcanics, and are interpreted as upwelling asthenosphere. Beneath the Eastern Alps, I image a high velocity structure, which continues east beneath the Pannonian Basin with depth and into the mantle transition zone (MTZ). The fast anomaly in the MTZ is distributed laterally as far as the Carpathians, the Dinarides and the Eastern Alps. The high velocity mantle material linking the structure beneath the Pannonian Basin with the Eastern Alps indicates a once continuous continental collision zone. Eastward extrusion from the Adria collision and detachment of the continental lithosphere beneath the Carpathians resulted in asthenospheric upwelling, which may have provided the driving force for extension of the Pannonian Basin.