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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.

Interpretation of Project MAGNET data (1959 to 1966) for Africa and the Mozambique Channel (Part I) ; Seismic ray tracing with applications to Africa (Part II)

Green, Alan G. 1973 (has links)
Part I: This part of the thesis is concerned with the interpretation of Project MAGNET profiles over the African continent and Mozambique Channel. The paths of the continental profiles lie between latitudes 5°N. and 22°S., while the paths of the profiles which cross the Mozambique Channel lie between latitudes 0° and 35°S. (figure (1)). The geology and geochronology of 'equatorial' Africa are described briefly in chapter (1). In chapter (2) a new method of magnetic profile analysis is introduced and applied to a number of simulated profiles. This method forms the basis of the interpretation of the continental Project MAGNET profiles (chapter (4)). In chapter (3) the various details of the reduction of the Project MAGNET data (e.g. the interpolation of the data, removal of the regional magnetic field, removal of the diurnal magnetic field) are described. The continental Project MAGNET data are interpreted in chapter (4) while the 'oceanic' data are interpreted in chapter (5). Part II: Until recently most seismological data have been explained in terms of spherically symmetric Earth models. Improved recording techniques (e.g. seismic arrays) and the increased number of recording stations have resulted in the discovery of large lateral variations of the seismic velocity in the crust and mantle which are closely correlated with major tectonic features (e.g. ocean ridges and trenches). It has therefore become increasingly necessary to consider laterally. heterogeneous Earth models when inverting seismological data. This part of the thesis is concerned with the development and application of some computer programs to trace seismic rays through laterally heterogeneous velocity media. In the first chapter the basic principles of seismic wave theory and the ray approximation are outlined. This will include: (i) A derivation of the ray path equations for a seismic ray travelling through structures in which the velocity is a function of three dimensions and two dimensions respectively. The velocity structures may be continuously varying and/or defined in discrete units bounded by velocity discontinuities. (ii) A derivation of the equations describing the geometrical spreading effect in velocity structures which are a function of two coordinates. The equations which represent the energy partitioning of a seismic ray at a finite velocity boundary (Zoeppritz's equations) are stated. (iiI) The method of interpolation of the velocity data and the integration procedure. (iv) A brief description of the computer programs. In chapter (2) the two dimensional computer program (i.e. the computer program which traces seismic rays through velocity structures which are a function of two dimensions) is applied to some 'standard' Earth models and in the final chapter this program is used (a) to derive a spherically symmetric velocity depth model from body wave data, which represents the average velocity beneath east and southern Africa, and (b) to test some models of the East African Rift obtained from interpretations of gravity data.

Sedimentary environments, sedimentary processes and river history in the lower Medway Estuary, Kent

Kirby, Robert 1969 (has links)
No description available.

Aspects of the palaeoecology of large predators, including man, during the British Upper Pleistocene, with particular emphisis on predator-prey relationships

Turner, Alan 1981 (has links)
This thesis discusses aspects of the palaeoecology of large predators, including man, during the Upper Pleistocene in Britain, with particular emphasis on predator-prey relationships. Upper Pleistocene is here taken as the Ipswichian (last) interglacial and the Devensian (last) glaciation. In addition to man, the term large predator includes lion, hyaena, wolf, leopard, bear, lynx and wolverine. The primary aim is to predict features of past predator and prey behaviour by integrating the results of modern ethological observations on similar or analogous species with the published evidence of Upper Pleistocene environments deduced from botanical, sedimentological and geomorphological investigations, and thus to extract information on trends in predator ecology and predator-prey relationships between the Ipswichian and Devensian. The study also examines the possibility that interpretations of human activity in Upper Pleistocene Britain have been founded largely on material accumulated by hyaenas, and discusses the value of examining past human behaviour from an ecological perspective in which man is regarded as one predator among many. The predictions of past behaviour are tested on vertebrate remains recovered from Upper Pleistocene deposits and how available in numerous museum collections. Much of the material derives from hyaena-accumulated bone assemblages in caves, and holds a potential wealth of information on the behaviour of this species and its predatory and scavenging activities. It is argued that the broad scope of the enquiry overcomes the shortcomings of this material which result from inadequate standards of recovery, recording and curation. The major conclusions reached in the study are: 1. That man and large mammals were seasonal occupants of Devensian Britain, on the evidence of reindeer antler remains, bear specimens in hyaena-accumulated assemblages and an analysis of tooth wear in horses. 2. That Ipswichian hyaenas found conditions more arduous than their Devensian counterparts, and may have died out at the end of Zone II of the interglacial, on the evidence of hyaena mortalities and the extent of bone consumption in hyaena-accumulated assemblages of the period. 3. That Devensian hyaenas did not tend to kill horses but instead scavenged their remains, most probably from lion kills, in view of the evidence for sexual parity in samples of horse teeth. 4. That much of the vertebrate material associated with Upper Palaeolithic industries and taken to show evidence of human economic activities is indeed the result of hyaena bone-accumulation, on the basis of comparisons with modern hyaena behaviour, and therefore inadmissable. 5. That an integration of present results with those from Europe and other parts of the world suggests that the importance of man as a member of the Pleistocene fauna may have been overemphasised.

The integration of laboratory data with flow simulation for application to seismic reservoir monitoring

Kirstetter, Olivier Hugues 2002 (has links)
No description available.

A sedimentological, diagenetic, and structural study in the middle tuffs, Borrowdale volcanics, English Lake District

Konig, Jacques Marcel 1964 (has links)
No description available.

The minor intrusions and structure of the Carlingford complex, Eire

Halsall, Trevor James 1974 (has links)
The Carlingford volcanic complex has an intense swarm of minor intrusions associated with it. Field work demonstrates that the swarm is composite, having involved the repeated injection of magma as dykes, cone sheets and complementary cone sheets in at least three rythmic cycles. Three major rock series are represented in these bodies: the tholeiitic basalt - craignurite series, the alkali basalt series and the high alumina basalt series, other rock types such as felsites, quartz feldspar porphyries and lamprophyres are present in minor proportions. Analysis of the structure of individual swarms suggests that basaltic magma was injected into the crust as an elongate ridge like body culminating in a cupola beneath the complex, from which cone sheet and radial dyke swarms emerged; linear dyke swarms arose from the ridge crest. Detailed geochemical investigations show, that the main magma series were derived by fractionation from basaltic parents; that two fractionation paths are represented in the alkali basalt series (the trachy basalt - tristanite series and hawaiite - mugearite - benmorite series); that craignurites represent a true fractionation product of tholeiitic magma and are petrochemically distinct from icelandites. Basalt fractionation at Carlingford was dominated by the separation of olivine and plagioclase at low pressure while the petrochemistry of the rocks suggests that the three parental stems - tholeiitic basaft, alkali basalt and high alumina basalt, were derived from a common parent by fractionation at higher pressure. Time relations indicate that common parent to be olivine tholeiite magma which it is suggested was formed at depths in excess of 60 km. Miscellaneous rock types, including felsites,lamprophyres and quartz feldspar porphyries are shown to have been derived by melting of crustal rocks during the injection of basic magma within the complex.

Real-time kinematic and fast static GPS measurements of ground deformation on Mount Etna, Sicily

Page, Delia 2000 (has links)
No description available.

Palaeomagnetic studies of Swedish varved sediments

Noel, Mark 1976 (has links)
No description available.

The geology of part of the province of Reggio-Calabria, Southern Italy

Sargent, G. E. G. 1979 (has links)
No description available.

Gravity monitoring of Mount Etna (Italy) through discrete and continuous measurements

Carbone, Daniele 2001 (has links)
No description available.

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