The Taurus Mountains are an E-W trending mountain range in southern Turkey, with an elevation of up to 3500 m. In the south central Taurides, the Beysehir-Hoyran-Hadim nappes, a series of thrust sheets of Palaeozoic to Early Cenozoic age, are emplaced onto a relatively autochthonous Tauride platform, known as the Geyik Dag. These thrust sheets consist of a variety of discrete tectonostratigraphic units of continental platform, rifted margin and oceanic (ophiolitic) origin. It is generally accepted that the relatively autochthonous Tauride platform and the associated thrust sheets restore as a north-facing passive margin during Jurassic–Cretaceous time; however, the Triassic and earlier tectonic setting of the Tauride units is contentious. New data (mainly structural and sedimentological) presented here tests contrasting tectonic models of Late Palaeozoic – Early Mesozoic Tethys ocean evolution. Also, new light is shed on the Late Cretaceous and Early Cenozoic break-up and emplacement of the Tauride units during closure of Tethys. The Late Palaeozoic Tauride stratigraphy consists of shallow-marine carbonate, sandstone and mudstone, characteristic of a proximal passive margin. Detailed stratigraphic logging, facies interpretation, compositional analysis and geochemical evidence supports a passive margin setting, with sediment derived from the Tauride “basement”. Early – Middle Triassic mixed siliciclastic/carbonate sediments are interpreted as representing rifting and subsidence. Late Triassic coarser terrestrial clastics (Cayir Formation) are considered to represent a pulse of rift-related flexural uplift. Sediment provenance during this time was from the underlying Tauride platform to the north of the studied area. A previous hypothesis that a Palaeotethyan ocean closed in this area during latest Triassic “Cimmerian” orogenesis is discounted. Instead, structural and sedimentary data suggest that all of the deformation relates to Late Cretaceous – Early Cenozoic southward emplacement of the Beysehir-Hoyran-Hadim nappes. A first phase of thrusting (thin-skinned) emplaced ophiolite and distal margin units, whilst a second phase (thick-skinned) thrust platform lithologies southwards onto the foreland. Evidence is also summarised, notably from the Palaeozoic – Early Mesozoic Konya Complex to the north, which illustrates the relation of the Tauride platform to other geological terranes in Turkey and elsewhere in the Alpine-Himalayan orogenic belt. This thesis increases understanding of large-scale tectonic and sedimentary processes associated with continental margins and orogenic development.

<p>The THUMS-Huntington Beach fault branches from the Palos Verdes fault zone and south of that point forms the southwestern border of the Wilmington and Huntington Beach anticlines. Wilmington and Huntington Beach oil fields are located nearby, with timing and trapping mechanisms closely related to the evolution of the California Continental Borderland. The T-HBF, being part of Inner Borderland, is associated with change in vector of regional stress. Previously, this fault has been interpreted as a discontinuous feature. Correlation of newly acquired 2-D and existing industry 2-D and 3-D seismic and well data made it possible to identify that this is a right-slip fault zone with three segments. The T-HBF is striking northwest and has an average dip of 75&deg; to the northeast. Wilmington and Huntington Beach anticlines are inverted basins formed as structural lows and then uplifted as a result of T-HBF activity in late Miocene-early Pliocene time. </p>

No description available.

Published mineralogical and diagenetic studies of the Derbyshire Platform focus upon the source of Mississippi - Valley type (MVT) mineralising fluids and hydrocarbon deposits or upon the diagenetic history of the area. This study aims to integrate these fields by developing a complete model for the geochemical evolution of the Derbyshire Platform and the surrounding basins, in line with the regional Variscan tectonic history of the area and the controls this imposed upon fluid flow. The study area is compared to diagenetic events on the southern margin of the Askrigg Platform and the adjacent Craven Basin which are thought to have been contemporaneous with events on the Derbyshire Platform. A sequence of late diagenetic calcite cements can be recognised on the Derbyshire Platform within vein systems and cross cutting relationships between veins and variations in cement type illustrate there were several phases of cementation. On the Askrigg Platform, burial calcite cements can be identified within veins and intergranular pores. On both the Derbyshire and the Askrigg Platforms, burial calcite cements were contemporaneous with hydrocarbon emplacement and MVT mineralisation. Compacting Dinantian - Namuiran shales in basins adjacent to the Derbyshire and Askrigg platforms offer the most likely source of fluids. Trace metals, hydrocarbons and fluids were progressively released from overpressured basins onto the platforms along fault systems. Fluids circulated on the platform within minor faults and fractures. Restricted volumes of fluid were released from the basins during the waning effects of Carboniferous extension, but the onset of Variscan compression in the mid-late Westphalian led to reactivation of fault systems and massive dewatering of the basins onto the platform. A model can therefore be established relating fluid flow to Variscan tectonic events in northern Britain.

<p> Proterozoic crustal provinces that underlie much of the United States record prolonged southward growth of the North American craton (Laurentia) between ca. 1.8 and 1.0 Ga. Exposures throughout central Arizona's Tonto Basin represent multiple generations of sedimentary basins formed during Proterozoic accretion. Metasedimentary rocks sampled across Tonto Basin resulted have identified remnants of a previously undated but potentially widespread Mesoproterozoic basin called the Yankee Joe Basin. Sediments of Yankee Joe Basin are particularly interesting because they have depositional age's ca. 200 m.y. younger than previously thought and because they are rich in detrital zircons with ages between 1.6-1.48 Ga, a time period not widely represented in the igneous record of Laurentia. Metasedimentary rocks with similar age and provenance are found in northern New Mexico and in the lower parts of the Belt Supergroup in northern Idaho, Montana, and Canada. Zircon ages and Hf isotopic characteristics suggest the distinctive 1.6-1.48 Ga grains might have been derived from non-Laurentian sources, most likely one or more formerly adjacent cratons such as north Australia. Circa 1.48-1.43 Ga units in the Yankee Joe Basin rest disconformably on Paleoproterozoic quartzite, and all were deformed together during northwest-directed foreland-style thrusting. This event was previously interpreted to represent the ca. 1.66-1.60 Ga Mazatzal orogeny. However, new findings challenge this view and suggest a major deformation event occurred ca. 1.47-1.45 Ga, possibly representing the Picuris orogeny as recently described in northern New Mexico. Regional thrust faulting during the Mesoproterozoic might have unroofed and removed significant portions of the Yankee Joe section, potentially shedding detritus north from the thrust front into the upper parts of the Belt-Purcell basin. </p><p> Detrital zircon ages and hafnium isotope compositions provide a critical test of sediment provenance and depositional age and were used to reassess sedimentary age and sources multiple Proterozoic unconformity-bound metasedimentary successions exposed across Arizona. These successions represent a series of ca. 1.75 to 1.3 Ga basins that span the Proterozoic accretionary provinces of southwestern Laurentia, representing key elements in the tectonic evolution of the continental margin. The ca. 1.75 Ga Vishnu Schist contains a bimodal detrital zircon age distribution with prominent Archean (2.5 Ga) and Early Paleoproterozoic (1.8 Ga) populations and minor juvenile 1.75 Ga input. The predominance of 3.3-1.8 Ga detrital zircon ages and initial epsilon Hf (&epsiv;Hf) values of +4 to -13 in both detrital grains of the Vishnu Schist and xenocrystic grains in plutons from cross-cutting plutons suggests the Vishnu Schist was derived primarily from recycling of the Mojave and other older basement provinces, possibly including one or more outboard cratons. In contrast, the ca. 1.74-1.72 Ga Jerome and ca. 1.72 Ga Alder successions of central Arizona, show a marked shift to strongly unimodal detrital zircon age distributions with initial &epsiv;Hf values ranging from +13 to -5, generally more positive and near-juvenile. Cross-cutting ca. 1.74-1.72 Ga plutons that intrude these rocks also have largely juvenile Hf isotopic signatures. The prominent ca. 1.73 Ga age peaks and relatively juvenile &epsiv;Hf values of detrital grains and plutons are consistent with first-cycle sediment derived from local arc systems formed during progressive assembly of the Yavapai province with the older Mojave province. The ca.1.66-1.63 Ga Mazatzal succession is more compositionally mature and contains broader unimodal detrital zircon age spectra, interpreted to represent increasing regional crustal recycling following the culmination of the Yavapai orogeny. </p><p> In the northern Tonto Basin, detrital zircon age populations from similar looking quartzite and shale successions were used to develop new regional correlations. First, the Houdon Quartzite of the Alder Group was correlated to the Pine Creek Conglomerate. Second, the Mazatzal Group that unconformably overlies the Alder Group, was found to be deposited ca. 1631 &plusmn; 22 Ma, consistent with the White Ledges Formation and the quartzite succession at Four Peaks. Third, a new detrial zircon population collected from the upper part of the argillaceous section in the core of the Four Peaks synform yield ages between 1591-1560 Ma suggesting this section is correlative to the Yankee Joe Formation. (Abstract shortened by UMI.)</p>

<p> The calculated extension (~111 km) across the Woodlark rift is incompatible with the > 130 km needed to exhume the Metamorphic Core Complexes on shallow angle faults (&lt; 30&deg;) using N-S extension in the Woodlark Basin. High resolution bathymetry, seismicity, and seismic reflection data indicate that the Nubara Fault continues west of the Trobriand Trough, intersects the Woodlark spreading center, and forms the northern boundary of the Woodlark plate and the southern boundary of the Trobriand plate. The newly defined Trobriand plate, to the north of this boundary, has moved SW-NE along the right lateral Nubara Fault, creating SW-NE extension in the region bounded by the MCC's of the D'Entrecasteaux Islands and Moresby Seamount. Gravity and bathymetry data extracted along four transect lines were used to model the gravity and flexure across the Nubara Fault boundary. Differences exist in the elastic thickness between the northern and southern parts of the lines at the Metamorphic Core Complexes of Goodenough Island (Te_south = 5.7 x 103 m; Te_north = 6.1 x 103 m) and Fergusson Island (Te_south = 1.2 x 103 m; Te_north = 5.5 x 103 m). Differences in the elastic strength of the lithosphere also exist at Moresby Seamount (Te_south = 4.2 x 103 m; Te_north = 4.7 x 103 m) and Egum Atoll (Te_south =7.5 x 103 m; Te_north = 1.3 x 104 m). The differences between the northern and southern parts of each transect line imply an east-west boundary that is interpreted to be the Nubara Fault. The opening of the Woodlark Basin resulted in the rotation of the Papuan Peninsula and the Woodlark Rise, strike slip motion between the Solomon Sea and the Woodlark Basin at the Nubara Fault, and the formation of the PAC-SOL-WLK; SOL-WLK-TRB triple junctions. The intersection of the Woodlark Spreading Center with the Nubara Fault added the AUS-WLK-TRB triple junction and established the Nubara Fault as the northern boundary of the Woodlark plate.</p>

No description available.

No description available.

Convergent continental margins are regions of intense deformation caused by the interaction of oceanic plates with continents. The spatial extent of deformation is broadly commensurate with the specific time scale of the causative phenomenon. For example, subduction-related short-term deformation is limited to <200 km from the margin, whereas long-term plate convergence cause deformation over ∼1000 km landward. Deformation is thus manifested in multiple ways, with attributes depending on the scale of measurement. In this thesis we investigate the use of two geophysical approaches in the study of deformation: 1) The analysis of potential-field anomalies to derive estimates of the elastic thickness (Te) of the lithosphere, and 2) The structural study of past and present subduction systems using seismic observations and modelling. Both approaches involve the development of appropriate methodologies for data analysis and modelling, and their application to the western Canadian landmass. Our findings are summarized as follows: 1) We develop a wavelet-based technique to map variations in Te and its anisotropy; 2) We show how a step-wise transition in Te and its anisotropy from the Cordillera to the Craton is a major factor influencing lithospheric deformation; 3) We implement a waveform modelling tool that includes the effects of structural heterogeneity and anisotropy for teleseismic applications, and use it to model the signature of a fossil subduction zone in a Paleoproterozoic terrane; 4) We use teleseismic recordings to map slab edge morphology in northern Cascadia and show how slab window tectonism and slab stretching led to the creation of the oceanic Explorer plate; 5) We use seismic signals from the subducting oceanic crust to calculate elevated Poisson’s ratio and infer high pore-fluid pressures and a low-permeability plate boundary within the forearc region of northern Cascadia.

Thesis (Ph. D.)--University of Hong Kong, 2008. / Also available in print.