Submitted by Irene Nascimento (irene.kessia@ufpe.br) on 2016-06-30T17:44:49Z No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação_JoséRicardo.pdf: 6453119 bytes, checksum: 0ee0cb3c7c1782b42a982a22935271cb (MD5) / Made available in DSpace on 2016-06-30T17:44:49Z (GMT). No. of bitstreams: 2 license_rdf: 1232 bytes, checksum: 66e71c371cc565284e70f40736c94386 (MD5) Dissertação_JoséRicardo.pdf: 6453119 bytes, checksum: 0ee0cb3c7c1782b42a982a22935271cb (MD5) Previous issue date: 2015-07-31 / PRH-26/ ANP / Vários trabalhos têm tentado abordar a evolução das margens conjugadas do Atlântico, incluindo o nordeste do Brasil e o oeste da África. Entretanto, o avanço de pesquisas anteriores tem sido dificultado em razão da falta de dados na região marginal da porção oriental do nordeste do Brasil, principalmente na área inserida entre a Zona de Cisalhamento de Pernambuco e o Alto de Touros. Este fato tem imposto limitações ao desenvolvimento de modelos regionais sobre a evolução geotectônica e paleogeográfica desta região, assim como na correlação com sua contraparte na África. Nesta dissertação é apresentada uma investigação realizada com base em dados gravimétricos, magnéticos e sísmicos regionais. Os resultados mostraram que esta região representa um alto do embasamento com a orientação regional das principais estruturas tectônicas (ENE-WSW), ortogonais as estruturas desenvolvidas durante o processo de abertura das bacias da Paraíba e da Plataforma de Natal (NNE-SSW e NNW-SSE). Sobre o embasamento continental formou-se uma plataforma estreita com uma cobertura sedimentar pouco espessa (0,8-2,5 km) e uma quebra abrupta da plataforma, criando uma vasta zona de bypass através do talude. A análise de uma seção sísmica profunda revelou que a crosta continental afinada (crosta transicional) representa uma estreita zona e que o limite crosta continental-oceânica (COB) está localizado a aproximadamente 100 km a leste da atual linha de costa, na Bacia da Paraíba, e a 70 km, na Bacia da Plataforma de Natal. A modelagem geofísica, integrada com a interpretação sísmica, indica que esta região é caracterizada por um afinamento abrupto da crosta continental, com a consequente ascensão súbita da Moho. Também há evidências da existência de uma zona de crosta continental extremamente afinada, a qual foi interpretada como crosta proto-oceânica. Estes novos dados demonstram que esta área apresenta fortes similaridades com margens rifteadas não vulcânicas ou pobres em magma. / Several studies have tried to address the evolution of the Atlantic conjugate margins, including Northeast Brazil and West Africa. However, past research advances has been hindered by a lack of data for the marginal region in the eastern portion of northeastern Brazil, extending from the Pernambuco Shear Zone to the Touros High. This situation has imposed serious limitations on the development of a regional view of the geotectonic and paleogeographic evolution of this area and on correlations with regional counterparts in Africa. Here, we present an investigation using regional gravimetric, magnetic and seismic data. The results show that this region represents a basement high with regional orientation of tectonic structures (ENE-WSW) orthogonal at structures developed during the open processes of the Paraíba and Natal Platform Basins (NNE-SSW and NNW-SSE). The continental basement forming a narrow platform with a thin sedimentary cover (0.8-2.5 km) and an abrupt shelf break, which created a large bypass zone towards the slope. The analysis of a deep seismic section revealed that thinned continental crust (transitional crust) occupies a narrow zone and that the continental-oceanic boundary (COB) is located approximately 100 km to the east of the present coastline, at Paraíba Basin, and 70 km, at Natal Platform Basin. Geophysical modeling integrated with interpretation of the seismic data suggests that this region is characterized by an abrupt thinning of continental crust, with an accompanying sudden rise of the Moho. There are also indications for the existence of a zone of extremely thinned continental crust, which was interpreted as protooceanic crust. Our findings suggest that the study area shows strong similarities to nonvolcanic or magma-poor rifted margins.

No description available.

Few philosophers, today, are doing more than simple recognition of Levinass debt to phenomenology when a thorough explication of how phenomenological methodology impacts Levinass work is needed. This dissertation is the needed discussion of methodology that has been so absent in Levinas as well as in so many of his interpreters. The purpose, herein, is to synthesize Levinass work, explicating it in terms of transcendental methodology, the result of which reveals Levinass claims to be more defensible when understood in these terms than when the full rigor of this methodology is not properly grasped. First, to connect Levinas to transcendental phenomenology a correct perspective of the phenomenological tradition is needed. I argue that phenomenology is a methodology that discloses those horizons that condition experience such that appearance takes on meaning. I further argue that it is important to see this disclosure as something open-ended and ongoing rather than a method capable of fully revealing a final telos. Levinas fits into this methodology by providing the ethical as just such a horizonal condition, while his constant returning to this theme highlights the need to keep reworking the description of its meaningful impact on experience. Second, I defend Levinas from those who claim his work cannot be phenomenological, based on what they see as an implied Jewish tradition informing his description. I argue that what must be understood is that Levinass reference to God, Biblical stories, and Jewish wisdom impose an unsettling language that is introduced to replace traditional phenomenological language that does not always allow for the goals phenomenology sets for itself. This imposition does not use the Jewish tradition to make his argument but as a vocabulary far better at describing the ethical condition than what is commonly used in phenomenology. The final step of explication involves the actual application of the methodology, now understood aright, to Levinass claims about the other, the self, and the ethical. The result is that once we understand the ethical as the infinite originative horizon out of which the conscious ego emerges, later interpretations of Levinas will be able to successfully move beyond his work.

The elucidation of the geologic processes that led to the creation of the Tibetan Plateau, a large area of thick crust and high elevation, is a fundamental question in geology. This study provides new data and insight on the geologic history of central Tibet in the Jurassic and Cretaceous, prior to the Indo-Asian collision, as well as the Gondwanan history of the Lhasa and Qiangtang terranes of the plateau. This investigation is centered on the Bangong suture zone near the town of Amdo and I present new geochronology, thermochronology, thermobarometry and structural data of the Amdo basement, an exposure of high-grade gneisses and intrusive granitoids. Using a range of thermochronometers, I show there were two periods of cooling, one in the Middle-Late Jurassic after high-grade metamorphism and a second in the Early Cretaceous. I attribute Middle-Late Jurassic metamorphism, magmatism, and initial cooling of the Amdo basement to arc related tectonism that resulted in tectonic or sedimentary burial of the magmatic arc. I propose that a second period of cooling, nonmarine, clastic sedimment deposition and thrust faulting in the Early Cretaceous is related to the Lhasa-Qiangtang collision. The thermochronology reveals limited denudation between the Cretaceous and the present, indicating the existence of thickened crust when India collided with Asia in the early Tertiary. U-Pb geochronology of the orthogneisses and detrital zircon geochronology of metasedimentary rocks suggests that the Lhasa and Qiangtang terrane were located farther west along Gondwanan's northern margin than most reconstructions depict.

Silicon (Si) isotopes have been extensively studied in low temperature environments but the science of Si isotopes in igneous material has been comparatively ignored. This is because the degree of isotopic fractionation at high temperatures is relatively small, making the accurate measurement of these variations extremely challenging. Using state-of-the-art analytical techniques and instrumentation, which deliver high levels of precision, the objective of this research is to rectify this omission. Specifically, this study aims to investigate whether there are systematic Si isotope variations within, and provide robust Si isotopic compositions for, the major silicate reservoirs on Earth. To this end, a broad range of mantle and crustal lithologies, sourced globally and from various tectonic regimes, have been analysed using high resolution MC-ICP-MS. Analyses indicate that the Si isotopic compositions of mantle-derived mafic and ultramafic material are extremely homogeneous. These data are used to calculate a Bulk Silicate Earth (BSE) average of δ³⁰Si = -0.29 ± 0.08 ‰ (2 s.d.). The degree of Si isotopic fractionation as a result of magmatic differentiation has also been assessed, and found to be small but resolvable between basalt and rhyolitic end-members. Finally, this research shows that, although igneous rocks and sediments derived from the continental crust can be relatively heterogeneous with respect to Si isotopes, bulk averages calculated for the upper, middle and lower continental crust are all very similar to that of BSE. Providing robust estimates for these reservoirs has greatly improved our knowledge of the behaviour of Si isotopes in silicate lithologies and provides a framework for further Si isotopic investigations of such material.

The West Iberia (WIM) and Newfoundland (NFM) continental margins formed over a succession of rift events related to the opening of the North Atlantic between the Late Triassic and the Early Cretaceous. They are characterized by a variable width Ocean- Continent Transition (Zone) where exhumed and serpentinized mantle has been cored. Results from 1-D well backstripping along the Portuguese shelf suggest 40-45% greater extension factors (β) than previous estimates. In addition, the age and duration of both the Late Triassic-earliest Jurassic and the Late Jurassic rifting episodes have been better constrained. It appears, for example, that the Late Jurassic rift propagates northwards along the margin, as inferred for the continental break-up during the Early Cretaceous. Combined backstripping and gravity modelling techniques (POGM), together with new bathymetry and sediment thickness grids, have been used to estimate the effective elastic thickness, T_e, of the lithosphere. Results along closely space profiles in the WIM reveal that T_e decreases from 15-40 km over unthinned Variscan basement to ≤ 15 km over stretched continental and transitional crust. Along strike, a good correlation is found between the modelled mechanical structure and the segmentation of the Variscan basement onshore. Discrepancies between observed and calculated anomalies are discussed in terms of other processes that affected the margin, such as serpentinization and inversion. Thermo-mechanical rheological modelling techniques have also been tested. The compiled software inputs the β's constrained from POGM to determine the thermal structure of the margin, which, in turn, has been used to construct models of rheology and, hence, T_e. The models predict an increase in the T_e of thinned continental lithosphere with age since rifting, between < 20 and > 35 km, and suggest that processes such as ductile shearing and mantle serpentinization might have permanently weakened the lithosphere. Results from POGM along conjugate profiles off WI and NF reveal a greater longterm strength of extended continental and transitional basement in the NFM (T_e's of 10-40 km). This analysis further supports the hypothesis that the low T_e's modelled in the WIM might be related to its complex structural framework. In order to explain the large asymmetries observed in the amount of basement subsidence (500-1300 in) between the WI and NF margins a lithospheric-scale "simple shear" rift model is proposed for the latest stages of rifting and continental break-up.

Iconoclastic discourse, as a critique of ‘idols’ of various kinds, has been appropriated by a range of different thinkers and traditions – often not always explicitly religious – throughout history. One of the more recent targets of iconoclasm is metaphysics, understood as a way of doing philosophy that appeals to an ideal or transcendent ground that is used to offer a totalising explanation of ‘reality’. For some reason, the issue of ‘metaphysical idolatry’ has become entangled with the problem of ‘writing’, or ‘representation’ more generally, which is pictured in some rather strange ways by a range of thinkers and theorists – including philosophers and theologians such as Jacques Derrida, Jean-Luc Marion, and Catherine Pickstock – in order to either challenge, or to be held accountable for, the ‘idolatry’ of metaphysical thought. It seems, however, that these strange pictures of writing compound rather than solve the problem of metaphysics, and it is towards pictures such as these that we direct our own iconoclastic critique. What many critics of metaphysics have failed to comprehend, we argue, is that metaphysics is a certain type of philosophical practice, and it must therefore be judged from this perspective. Idolatry itself has, since biblical times, been understood as a form of sinful practice, and unless we understand iconoclastic problems in a praxeological way, we risk basing our critical arguments on delusional assumptions. We turn to the work of thinkers as diverse as Marx, Wittgenstein, Heidegger, Merleau-Ponty, Ryle, Bourdieu, Ingold, and others, who have challenged metaphysics, and the strange pictures that metaphysical thought has inspired, through the adoption of what we call a praxeological approach. It is from this perspective, we argue, that we can make iconoclastic judgements, and justify these judgements, in a way that avoids the speculative conundrums of some other more problematic approaches.

In central Anatolia, Turkey, a strand of the former northern Neotethys Ocean subducted northwards under the Eurasian (Pontide) active margin during Late Cretaceous–Early Cenozoic time. Subduction and regional plate convergence were associated with the generation and emplacement of accretionary complexes and supra-subduction zone-type ophiolites onto former passive margins of microcontinents. The resultant suture zones contain Late Cretaceous to Middle Eocene basins (“The Central Anatolian Basins”) including: 1) the Kırıkkale Basin; 2) the Çankırı Basin, 3) the Tuz Gölü Basin and; 4) the Haymana - Polatlı Basin. Using stratigraphic logging, igneous geochemistry, micropalaeontology and provenance studies, this study tests two end-member models of basin evolution. In model one, the basins developed on obducted ophiolitic nappes following closure of a single northern Neotethys Ocean during the latest Cretaceous. In model two, northern Neotethys comprised two oceanic strands, the İzmir-Ankara-Erzincan Ocean to the north and the Inner Tauride Ocean to the south, separated by the Niğde-Kırşehir microcontinent, which was rifted from the Gondwana continent to the south. In this scenario, the basins developed as accretionary-type basins, associated with north-dipping subduction which persisted until the Middle Eocene when continental collision occurred. Where exposed, the basements of the Central Anatolian Basins comprise the Ankara Mélange, a mainly Upper Cretaceous subduction-accretion complex and the western/northern margin of the Niğde-Kırşehir microcontinent. New geochemical data from the composite basement of the Kırıkkale Basin identify mid ocean-ridge basalt (MORB), here interpreted to represent relict Upper Cretaceous Neotethyan oceanic crust. During the latest Cretaceous, the Kırıkkale and Tuz Gölü Basins initiated in deep water above relict MORB crust and ophiolitic mélange, bordered by the Niğde-Kırşehir microcontinent to the east where marginal facies accumulated. Further west, the Haymana-Polatlı Basin represents an accretionary-type basin constructed on the Ankara Mélange. To the north, the Çankırı Basin developed on accretionary mélange, bounded by the Pontide active margin to the north. Palaeocene sedimentation was dominated by marginal coralgal reef facies and siliciclastic turbidites. Latest Palaeocene–middle Eocene facies include shelf-type Nummulitid limestone, shallow-marine deltaic pebbly sandstones and siliciclastic turbidites. This thesis proposes a new model in which two north-dipping subduction zones were active during the late Mesozoic within northern Neotethys. In the south, ophiolites formed above a subduction zone consuming the Inner Tauride Ocean until the southward retreating trench collided with the northern margin of the Tauride continent emplacing ophiolites and mélange. In the north, subduction initiated outboard of the Eurasian margin triggering the genesis of supra-subduction zone ophiolites; the subduction zone rolled back southwards until it collided with the Niğde-Kırşehir microcontinent, again emplacing ophiolites during latest Cretaceous time. Neotethyan MORB still remained to the west of the Niğde-Kırşehir microcontinent forming the basement of the Kırıkkale and Tuz Gölü Basins. Latest Palaeocene–middle Eocene regional convergence culminated in crustal thickening, folding, uplift and strike-slip faulting which represent final continental collision and the geotectonic assembly of central Anatolia.

This thesis seeks to identify, explain, and differentiate the problems of existential doubt and the burden of choice in today’s world versus the previous epochs of human existence. It will attempt to discern the relevant differences in the types of existential doubt, illustrate how these differences came about, and analyze the strength of a potential solution to these problems. My aim is to critique Dreyfus and Kelly’s portrayal and solution to these problems in a way that can further promulgate discussion on an increasingly relevant topic in philosophy, mental health, and science. The conclusion will provide a novel understanding of contemporary nihilism that might be of use in combating this epidemic.

Abstract Three dimensional finite strain and kinematic data from the Resolution Island Shear Zone, Fiordland, New Zealand record the progressive evolution of a lower crustal metamorphic core complex. The Resolution Island Shear Zone is a mid-Cretaceous (~114-90 Ma) extensional shear zone that juxtaposes high-pressure (P~17-19 kbar) garnet-granulite and eclogite facies orthogneiss from the lower crust against mid-crustal (P~6-8 kbar) orthogneiss and paragneiss along a low-angle upper amphibolite facies ductile normal fault. In the lower plate of the Resolution Island Shear Zone the high-pressure garnetgranulite and eclogite facies gneissic foliations (S1) are attenuated by granulite facies extensional shear zone foliations (S2). Retrograde metamorphism marked by the breakdown of omphacite and garnet to amphibole and feldspar in S2 foliation records the unloading of the lower plate during extension. Continued extension localized strain into weaker amphibole and feldspar-bearing lithologies. Upper amphibolite facies shear zones anastomose around rigid lenses that preserve the S1 and S2 fabric. Upper amphibolite facies shear zone fabrics (S3/L3) that envelop these pods display a regional-scale domeand- basin pattern. These shear zones coalesce and form the Resolution Island Shear Zone. Coeval with the formation of the Resolution Island Shear Zone, a conjugate, southwest dipping, and lesser magnitude shear zone termed the Wet Jacket Shear Zone developed in the upper plate of the Resolution Island Shear Zone. Three-dimensional strain analyses from S3/L3 fabric in the Resolution Island Shear Zone show prolate-shaped strain ellipsoids. Stretching axes (X) from measured finite strain ellipsoids trend northeast and southwest and are subparallel to L3 mineral stretching lineations. Shortening axes (Y, Z) are subhorizontal and subvertical, respectively, and rotate through the YZ plane of the finite strain ellipsoid. This pattern reflects the dome-and-basin geometry displayed by anastomosing S3 foliations and indicates the Resolution Island Shear Zone developed in the field of constriction. Threedimensional kinematic results indicate a coaxial-dominated rotation of stretching lineations toward the X-axis in both the XZ and XY planes of the finite strain ellipsoid. Results suggest that a lower crustal metamorphic core complex developed in a constrictional strain field with components of coaxial-dominated subvertical and subhorizontal shortening. Mid-Cretaceous (~114-90 Ma) extensional structures exposed in Fiordland, including the Resolution Island, Wet Jacket, Mount Irene and Doubtful Sound shear zones and the Paparoa metamorphic core complex allows the reconstruction of a crustal column that describes the geometry of mid-Cretaceous continental rifting of Gondwana. The overall symmetry of crustal-scale structures during continental extension suggests kinematic links between flow in the lower crust and the geometry and mode of continental extension. This result is consistent with numerical models of lithospheric rifting that predict the lower crust has a primary control on the style of continental extension.