Analysis of natural assemblages reveals that the architecture of the ozarkodinid conodont feeding apparatus remained conservative throughout two hundred million years of evolution. The apparatus was differentiated into an anterior array which performed a rasping and/or slicing function and its supporting structures were probably homologous to the dental cartilages of the living agnathans. The taphonomy of the apparatus indicates that the majority of natural assemblages represent carcasses that came to rest at a high angle to the sea floor, suggesting the presence of soupy substrates. Analysis of conodont hard tissue histology has led to a new model of element growth. This is used to reinterpret the affinity of the hard tissues themselves as opposed to the competing methodology which interprets the hard tissues first. Conodont elements are composed from numerous odontodes, and individual elements can be considered as odontocomplexes. Analysis of pattern formation in conodont element growth provides a new means of understanding these structures. The pattern of growth exhibited by many conodont elements is similar to that of the dentigerous jaw bones of acanthodians, and to that of lungfish toothplates. The periodic addition of odontodes to conodont elements provides a mechanism by which the paradox of growth and function may be resolved. The identification of internal discontinuities as representing episodes of function m the growth record of conodont elements indicates that the animal retained its feeding array throughout life rather than periodically shedding and replacing component elements. The functional morphology of pairs of elements dissected from natural assemblages reveals that, even though conodonts lacked jaws, some groups evolved a level of dental occlusion unrivalled before the rise of mammals, occurring in conodonts at least several tens of millions of years earlier. Comparison with the functional morphology of other taxa indicates that this level of occlusion was maintained by an additional unpreserved structure, comparable in function but not homologous to a jaw.

This work represents a revisional study of many of the species of the family Calymenidae Milne Edwards, 1840 (Trilobita) from the Ordovician, Silurian and lower Devonian of NW Europe. Taxa from Britain. Norway, Sweden and Czechoslovakia have received particular attention, and where appropriate comparisons have been made with non-European species. Most of the chapters are arranged on a taxonomic basis; one deals with the calymenid fauna from a single region (Middle Ordovician calymenids from Norway), and another is concerned with some evolutionary trends in Ordovician md Silurian species (Chapter F ). One new subfamily (Flexicalymeninae), three new genera (Quadricalymene, Tapinocalymene, Palacalymene), and thirteen new species are erected.

The amphibolites and mafic schists which occur in the Older Precambrian rocks of the Grand Canyon are divided into five major groups on the basis of field occurrence and mineral composition :( 1) anthophyllite- and cordierite-anthophyllite- bearing rocks (2) early (plagioclase-hornblende) amphibolites (3) Granite Park mafic body (4) hornblende-bearing dykes (5) tremolite-bearing- dykes. Cordierite-anthophyllite rocks and associated mafic schists represent sedimentary types which attained their bulk composition prior to metamorphism. They were derived in varying degrees from basic igneous materials which had suffered intense alteration and loss of lime and alkalis, probably by reactions with sea water. The early amphibolites were originally a series of lavas and tuffs of approximately basaltic composition. These meta-volcanic rocks have a tholeiitic character, and trace element considerations indicate that they may have formed in an island arc environment. Field and chemical data for the Granite Park mafic body strongly suggest that it originated as a layered series of plagioclase-rich cumulates. The body shows calc-alkaline chemical trends but with some affinity to tholeiitic rocks. Hornblende-bearing dykes range from ultramafic types composed only of hornblende plus opaques, to more normal plagioclase- hornblende amphibolites; the original composition of the majority of the dykes was probably in the basalt to basaltic-andesite range. They are strongly tholeiitic and may represent either ocean floor or island arc intrusives according to trace eluent data. Tremolite-bearing dykes are highly magnesian in composition, plot as early differentiates, and belong to either the calc-alkali or the tholeiitic series.

No description available.

No description available.

This thesis considers two main topics in the field of applied geochemistry, namely: a) The application of Direct-reading optical spectrometers to the analysis of geochemical samples, and b) The use of computer aided numerical analysis in the interpretation of univariate and multi-variate geochemical data. For the purposes of this exercise, the Pirejman area of SE Turkey was chosen as a study area. This district contained known lead-zinc mineralization, and was also potentially chromite bearing since a large serpentinite body cropped out in the western portion of the area. As a result of this study, a number of chromite and magnetite pods were found. The study of spectrometric analysis draws attention to the importance of the composition of the buffer mixture, ignition temperature and grain size of samples prior to analysis. It is demonstrated that the special background channel used in the ARL 29000B Direct-reading Spectrometer is unsuitable as a base upon which to adopt a correction procedure to eliminate matrix effects. The spectrometer is found to suffer from serious matrix effects, and it is shown that an effective correction procedure must therefore rely on the relationships that exist between variations in the major element contents and the induced interference in trace element readings. A computerized correction and conversion procedure is developed. The limitations, requirements and means of data storage and selective retrieval of geochemical data are investigated. A review of computer-orientated data processing techniques suitable for application to geochemical exploration data is presented. A new approach to the problem of the selection of optimum trend surface is proposed, involving a critical consideration of the components which make the deviations from a given trend surface. The use of Discriminant analysis as a final classification technique for results obtained by both Cluster and Principal Component analysis is discussed. In order to obviate the possibility of misclassifying an unknown sample by Discriminant analysis, it is proposed that a quantity (in standard deviation units), called the "standardised discriminant score distance", is calculated with respect to each of the groups between which the discriminant score of the unknown individual lies. The geology and mineralization of the Pirejman area is described. Primary dispersion patterns adjacent to known mineralization are investigated. Various data processing techniques are applied to regional rock and drainage sediment data obtained from the Pirejman area. Using a number of control features, the resolving capability of these computer-orientated techniques is evaluated. The power of Discriminant analysis as a means of testing a geochemical model, and predicting other areas of interest is demonstrated.

A detailed study of Neogene Ostracoda fauna has been made from closely sampled sections in the Adana and Antakya basins of southern Turkey. The Quaternary (Early Pleistocene) fauna studied has been obtained from the bore-holes drilled in the Mediterranean and in Cyprus. Some samples collected by Prof, P.C. Sylvester-Bradley from the Miocene and Pliocene of Cyprus have also been studied and compared. A Biozonation is proposed by means of Ostracod assemblages for the stratigraphic position of the sections studied. The Ostracoda assemblages are compared with those of Neogene stratotypes. It shows that most of the biozones can be recognized outside the studied area, particularly in Italy and in Greece. Paleoecological interpretations are based on the presence and relative abundance of indicator genera which may give a general idea about the depth and salinity of depositional environment. Four different types of realms are reflected in the Ostracoda assemblages (a deep open marine, a moderate marine, a shallow marine and a brackish environment) (Chapter I). The assumptions are made for the interpretation of paleo-environment and comparisons between the two basins (Chapter II). The systematic part of the research deals with about 200 species. A new genus Sylvestra and 73 new species are proposed. Two subgenera and some species are renamed (Chapter III).

The thesis is concerned with the Dan yr Ogof Caves located in the Carboniferous Limestone of the north outcrops of the South Wales Coalfield. The caves consist of one major system, called Dan yr Ogof, and one other major cave called Tunnel Cave, as well as a variety of smaller caves and potholes. Despite extensive discoveries in the past ten years large extents of cave passages remain unentered and only minimal progress has been made from the major stream input points. While they at present total over 17 kilometres their ultimate extent is likely to at least double this figure. The caves are shown to be comparatively youthful, having been initiated subsequent to the start of the Pleistocene Period, but show a maturity of form which is largely attributable to their favourable geological setting and to the recent climatic history of the area in which they are located. The latter is also held to account for the variety within the three main north-south limbs, for rejuvenation and intensive back-cutting by the River Haffes has been responsible for river capture and the termination of main stream flow into the eastern-most of the limbs. Jointing and faulting are shown to be of very great importance to the orientation and structure of passages throughout the catchment area. However, a hitherto unrecognised syncline is shown to be of major importance in controlling the trend of the most southerly passages which form the main conduit between the bottom end of the north-south feeder limbs and the resurgence. This syncline is the outermost manifestation of a major structural disturbance lying to the south. The large number of faults identified in the cave has led to a detailed consideration of relationships with the surface and it is suggested that an extensive and complex network of faults exists. These are arranged en echelon and are for the most part sub-parallel and trending slightly east of north. A considerable quantity and variety of sediments exists within the caves and some observations are made concerning the origins and chronology of these deposits although it is recommended that they are subjected to specialist investigation at a subsequent date.

Troodos Ophiolite is a remnant of Tethyan oceanic crust of Cretaceous age with well-preserved but complex extensional tectonics along its northern flank. Recent geological studies have provided improved models for the formation and extension environment of Troodos and its associated mineralisation. A geophysical program of seismic refraction, electromagnetic (MT-TEM) and potential field exploration has evaluated and developed aspects of these models. Analysis of aeromagnetic, satellite, and regional geophysical datasets suggests that the Solea and younger Larnaca ridge structures are comprised of NNW-NW oriented half graben cut by near-orthogonal transcurrent features. The known mineralisation was controlled by the extensional faulting. Although partially obscured by sediments, the Larnaca structure exhibits clearer regional anomalies and its western flank was the focus of the seismic refraction and MT-TEM surveys. Four refraction lines were recorded parallel and perpendicular to the proposed Larnaca axis. The 2D velocity structure of the oceanic Layer 2 and upper Layer 3 equivalent units was modelled to depths of 2.5-3.0 km, and revealed NW trending, normally faulted half graben dissected by reactivated ENE faulting with minor transform displacement. The compartmentalized "chequer board" tectonics are down faulted at the ophiolite-sediment contact, and the sediments thin towards the Larnaca axis. An apparent moho reflection occurred at 6.0 - 7.0 km. The MT-TEM and potential field data confirmed and constrained the Larnaca extensional model. Detailed TEM reconnaissance studies on a 3.31 km2 grid at Mathiatis-Sha modelled the Layer 2 resistivity structure to depths of 300 m, and refined the relationship between faulting and mineralisation for northern Troodos. Rigourous testing of the TEM method has established it as a powerful mineral exploration tool in the ophiolitic environment. The integrated model correlates with modern and ancient analogues and provides a framework for tectonic studies within an intermittent spreading regime.

This thesis examines the radiochemistry of the Devonian sediments of the Orcadian Basin, NE Scotland, the Hornelen Basin, SW Norway, together with the SW Wales. A detailed study of the radiochemistry linked to standard sedimentological and geochemical techniques has permitted the utility of portable gamma-ray spectrometry to be assessed. There are no systematic stratigraphic changes in the relative abundances of K, U, Th or in the ratios Th/K and Th/U for either lacustrine or non-lacustrine sediments of the Devonian Orcadian Basin. Spatial radioelement variations related to lithology and source chemistry are more important for characterising the basin infill. Palaeoenvironmental reconstructions, combining sedimentology and radiochemistry, are presented for stages in the evolution of the northern Orcadian Basin. Differing K abundances from the Sandwick lacustrine sequence indicate separation of two depositional areas by a buried basement ridge. The different provenance of the southern and northern marginal fans in the Hornelen Basin, Norway, is reflected by Th and K. Provenance links between the basement and the marginal breccias of the Turriff Basin could be characterised radiochemically and were distinct from the main Lower Old Red Sandstone sediments derived from the Strichen granite. Gamma-ray characteristics linking basement and sediments elsewhere in the Orcadian Basin were less conclusive, implying that the local basement was a minor contributor to the sediment budget. Uranium enrichment is associated with (i) sediments in close proximity to Caledonian granitic basement and (ii) lacustrine intervals. U enrichment is a product of both syndepositional fixation in algal sediments and limited later mobilisation, predominantly restricted to the vicinity of the basement with the greatest concentration along synsedimentary faults. U (5 ppm) and Th (8 ppm) abundances define the zone of mineralisation associated with algal sediments. Lacustrine intervals were correlated using U only for widespread lacustrine conditions; as lacustrine intervals become marginal, U concentrations decrease and correlations are speculative. Lacustrine laminites are geochemically distinguished from sandflat sediments having higher Zr, Y, Cr, Nb, V and SiO2 contents.