Systematic soil-gas surveys were carried out in Northamptonshire to investigate the distribution of radon and its controlling factors. This followed reports in 1988 of indoor radon levels in the county exceeding the Action Level of 200 Bq m-3. Over 3300 observations were made using a soil-gas emanometer in traverses crossing all geological formations. Over each formation results were found to be log-normally distributed, falling within 95% Confidence Limits. The results are compared with 1026 indoor measurements provided by local authorities. Direct comparisons cannot be made due to different controlling factors; the concentration of radon in soil-gas is determined by the permeability of the source rock and overlying soil and by climate and weather, particularly temperature and wind run. Indoor radon is also affected by the nature of the house construction, particularly the floor, and heating and ventilation. Both sets of observations show that radon occurrence is primarily controlled by the underlying geology; the relationship is presented as a Radon Hazard Map for Northamptonshire. The highest soil-gas radon levels occur over the Northampton Sand Formation where indoor levels reach 1600 Bq m-3, clearly presenting an elevated health hazard. The Marlstone Rock Bed, Upper Lincolnshire Limestone and Glacial gravels are also an elevated hazard. Hazard groups are defined as elevated on permeable strata where soil-gas Rn-222 is 11 Bq L-1 or over; moderate where soil-gas Rn-222 is 6-8 Bq L-1 on permeable strata, or 11 Bq L-1 or over on impermeable strata; slight where soil- gas Rn-222 is 5 Bq L-1 or less on permeable strata, or 6-8 Bq L-1 on impermeable strata; and low on impermeable strata where soil-gas Rn-222 is 5 Bq L-1 or less. Indoor results were also used in defining the hazard groups. Of the formations designated as elevated, all extend into adjacent counties, where soil-gas radon surveys are strongly recommended.

Wilson County is situated in the southern part of the Midcontinent region of the United States. The Nemaha Ridge lies to the west, the Bourbon Arch to the north, the Ozark Dome to the east, and the Amarillo-Wichita-Arbuckle complex to the south. Extensive field mapping was done in order to determine the geologic characteristics of the strata and to delineate the limits of deposits of limestone (for cement, lime, and road aggregrate), of clay (for brick, tile, and other building materials, and as a mixer in the rock-wool industry), and of coal (for heating purposes); this study and an associated study of bore-hole data from thousands of wells drilled for oil and gas have provided new insight into many fascinating aspects of Kansas geology. The Precambrian basement, encountered at depths below 355 m, includes granite, syenite, schist and gneiss. Through the Paleozoic there was extensive sedimentation ranging from varied coarse detritus from surrounding areas of orogenic uplift to Pennsylvanian epicontinental carbonates containing deltaic and channel filling clastics from the east, south, and west. Five unconformities were recognized below the Pennsylvanian which can be seen throughout the area as cyclic sequences of limestone, sandstone and shale. Six major cyclic units can be recognized over several hundred square kilometers with persistent sedimentary and biological features. They are attributable to Milankovitch-type cycles invoked to explain the nature of glacial deposits of Northern Europe. The great variety and abundance of marine plants and invertebrates reflect the changing geological environment. The mound lithofacies is dominantly a calcilutite with phylloid algae, the channel and rim lithofacies are calcarenites with echinoderm debris and brachiopods respectively. The area contains only two contrasting structural features of interest. The Fredonia Dome is a short complex anticlinal feature which is important for oil and gas production. The Silver City Dome is attributed to intrusion by several Cretaceous sills of lamproite encountered in boreholes; a very micaceous yellowish clay represents the lamproite at the outcrop. The youngest strata encountered are Tertiary and Quaternary gravels containing abundant chert pebbles derived from chert-rich limestones to the northwest; the gravels were deposited by vigorous migrating streams and rivers.

During the 1990 Kenya Rift International Seismic Project (KRISP 90) a 450 km E-W crustal refraction profile was undertaken across the Kenya Rift, a late Tertiary to Recent extensional feature associated with extensive volcanic activity. The P-wave data have been analysed using 2-D ray-tracing, finite difference and reflectivity dynamic modelling. A simultaneous velocity and travel time inversion has been applied to the forward model to test its uniqueness and resolution. The analyses show an asymmetric sedimentary basin which is thickest against the rift's major western boundary fault. The crustal velocities vary from 6.2 km/s in the Archaean craton to the west of the rift to about 6.0 km/s in the Proterozoic orogenic belt along the remainder of the profile. The crustal thickness outside the rift varies from 38 3 km adjacent to the rift's western margin and 34 2 km to the east. Beneath the rift itself the thickness is only 30 2 km. The upper mantle velocity is generally about 8.0 km/s except beneath the rift where it is consistently low at 7.6 - 7.8 km/s. This anomalously low velocity suggests a 5 - 6% partial melt. The combined seismic and gravity model supports the contention that convective processes in the mantle are dynamically supporting the uplifted East African Plateau. Kinematic and dynamic modelling of the S-wave field show that upper crustal phases have been recorded only outside the rift. Mid and lower crustal S arrivals do not seem to have been attenuated underneath the rift axis, precluding an extensive hot regime at lower crustal depth. A reflected phase is observed from an interface within the mantle beneath the western flank of the rift. Detailed analyses of this phase confirm the presence of a high velocity layer (8.4 km/s) below 60 km: compositional anomalies as well as crystal orientation have been suggested as an explanation for the observed velocity structure. This evidence may delimit the lateral extent of the upper mantle low velocity zone underneath the graben itself. A model of extension via simple shear in the upper crust and pure shear in the lower crust and upper mantle is suggested. The presence of a small diapir under the Kenya Rift, radiating from a 'weak' plume seated under the East African Plateau, is envisaged; the diapir appears to have spread asymmetrically towards the Proterozoic lithosphere to the east of the rift.

As abundant and widespread apex predators, elasmobranchs play influential roles in the food-web dynamics of marine communities. This has obvious implications for fisheries management and marine conservation. For successful conservation, the ecology of a species must be known. An understanding of extinct species ecology is also useful. Unfortunately, diet a key component of a species’ ecology, is relatively understudied in elasmobranchs. For a majority of elasmobranch species, little or no quantitative dietary data exists. This reflects the limitations of current dietary defining methods. This thesis presents two alternative methods that can be used to determine the diet of extinct and extant elasmobranchs: meso-style wear analysis and 3D tooth microtextural analysis. These wear techniques can be applied to small sample sizes, and sampled animals with no stomach contents, thus reducing the impact of study on wild elasmobranch populations. The techniques can also be applied to dried and fossil samples, further reducing the impact of study on wild populations and providing a means for the study of extinct species. Furthermore, these wear techniques provide additional advantages over the traditional methods of stomach contents analysis and observation. The wear, measured through the methods outlined in this thesis, accumulates over a longer timescale. The “snapshot bias” associated with traditional methods is thus overcome when analysing diet via meso-style analyses or 3D microtextural analyses. This thesis also investigates the impact of sediment abrasion to 3D tooth microtextures. Results show that care needs to be taken when comparing fossil specimens originating from deposits with differing sediment compositions. These findings are applicable to any study using 3D microtextural techniques on fossil specimens of any species, as all have been exposed to sediment abrasion before fossilisation. This is the first time that these alternative wear methods have been applied to elasmobranchs. They have displayed the potential to be a powerful tool for the dietary analysis of living and extinct elasmobranchs in the future.

No description available.

The mineralogical bibliography of Leicestershire, up to July, 1972, has been examined and critical analyses have been made of its 1375 references. The 134 mineral species recognized as indigenous to the county have been examined both physically and in relation to their individual geological environments. The physical examination has included X-ray diffraction techniques, qualitative and quantitative analysis. As a result certain species, formerly regarded as indigenous, have been discredited. 65 species have been erected as new county records and 5 new to British records. The geological environments of the minerals have been examined, one section of the work taking the form of an outline of the geology, another, the final section, examining the minerals in their genetic relationship to the geology. Although currently conceded that the allocation of mineral associations to set ''types" of ore genesis is no longer acceptable, an attempt has been made to allocate those found in Leicestershire to the set "types" as described by Park and MacDiarmid (1970) as follows:;1. Pegmatites.;2. Hypothermal deposits.;3. Mesothermal deposits.;4. Epithermal deposits.;5. Telethermal deposits.;6. Syngenetic deposits.;7. Supergene effects.;Rock forming minerals have only been examined where such species have been found in euhedral development, and they are not described as inherent components of rocks. Where problematical phenomena have been encountered during the course of the work, e.g. the anomalous fluorescence of chalcocite under short wave ultraviolet light, hypotheses have been erected to account for them. Each species has been examined in the order set out by Hey (1962) in his Chemical Index of Minerals, and the descriptive mineralogy has been divided into 12 sections: I The Elements II The Sulphides III The Oxides IV The Halides V The Carbonates VI The Nitrates VII The Silicates VIII The Phosphates IX The Vanadates X The Sulphates XI The Molybdates and Tungstates XII The Hydrocarbon Compounds.

A fauna of more than sixty species of Silurian Gastropoda is descrihed from the Arisaig Group of Nova Scotia. Two new genera, Anapetopsis and Arjamannia, are proposed and thirteen new species: Pharetrolites bambachi, Plectonotus boucoti, Plectonotus cherylae, Tritonophon kivitalonae, Anapetopsis maclearni, Anapetopsis lalajae Mimospira abhae, Arjamannia aulangonensis, Haplospira sibeliuxeni, Naticonema kauffmani, Cyclonema (C.) lydiamariarum, Naticopsis trevorpatriciorum and Morania (?) boltoni. Particular emphasis is given to the systeaiatics, ontogeny, functional morphology and palaeoecology of members of the subfamily Plectonotinae (Bellerophontacea) which characterise much of the Arisaig Group. The palaeoecology of other gastropod associations from the Arisaig Group is discussed and the sequence of faunas is related to the advance of barrier conditions into the shallow marine environment prevailing at Arisaig during the Silurian.

The Leicestershire coalfield constitutes a NW-SE orientated area of approximately 125 km2, centred on the town of Coalville in the East Midlands. The area is underlain by Carboniferous, coal-bearing strata of Westphalian A and B age. In the south the Carboniferous rocks are concealed below Permo-Triassic sediments. The investigation was restricted to the parts of the Leicestershire coalfield worked by British Coal deep mines. A synoptic view of the entire coalfield was taken, using exploration borehole data and underground quality control samples (where available). The study describes aspects of these data as they relate to the geology and depositional setting of the Leicestershire coalfield. The observed geometry and distribution of the coal seams and interseam sediments are related to the causative depositional processes. Computer modelling of the data examined the lateral and vertical lithological relationships within the Westphalian A and B succession of the Leicestershire coalfield in three representative parts of the stratigraphic interval, namely the middle section of the Westphalian A, the Westphalian A-B contact, and the mid Westphalian B. The lateral and vertical lithological relationships were defined using isopach and structural contour maps as well as correlation (scatter) diagrams. This study shows that there is probably not one single control on sedimentation, but a complex interaction of factors that have led to the deposition of the coal and coal-bearing strata in the Westphalian of the Leicestershire coalfield. The most important factor appears to be base level change, and resultant changes in water table level. Base level changes in turn may be controlled by tectonics, eustacy or doming of the peat during growth. There is a significant change in sedimentary style between the mid Westphalian A and the mid Westphalian B. Controls on sedimentation changed during the Westphalian, from predominantly structural factors in the mid Westphalian A to factors inherent in the depositional system in Westphalian B. Subsidence in the Westphalian A was in response to regional crustal extension and took place along the faults bounding the block and basin topography of the basement. Subsidence was rapid and basin fill sequences were thick, but coal seams were thin. With relaxation of extensional tectonics isostatic readjustment and thermally induced subsidence took place in the Westphalian B, with sedimentation keeping pace with the subsidence so that deposition occurred in shallow water which meant that the sediment and coal accumulated as a result of compactional, topographical and depositional factors.

The stable isotope composition (δ18O and δ13C) of biogenic (low-magnesium) calcite is commonly used as a palaeoenvironment proxy. These proxies are used to help understand the palaeotropical environment in the Brigantian to help elucidate the timing of the onset of the Late Palaeozoic icehouse. However, to validate isotope data there needs to be an understanding of the environment in which the constituent organisms lived and the preservation of their calcitic shells must be assessed to ensure resultant data are reliable. This study focussed on shell beds at two localities on the Derbyshire carbonate platform that expose (Brigantian) age limestones deposited in open water, inner to mid-ramp settings. Palaeoecological analysis of the shell beds revealed a high dominance (but low diversity) of Gigantoproductus species (Brachiopoda). Specimens of this genus were collected from these localities and preservation analyses were conducted. This includes ultrastructure analyses via scanning electron, cathodoluminescence microscopy (SEM and CL), and measurement of trace element composition using laser ablation with inductively coupled plasma mass spectrometry (LA ICP-MS). Some species of Gigantoproductus have thick valves, allowing geochemical sampling to be conducted at high resolution across the growth lines of the shells. SEM and CL analyses commonly revealed fine ultrastructure detail preserved in the non-luminescent calcite of the prismatic shell layer. Specimens showing the best-preserved ultrastructure and dull or non-luminescence underwent analysis of trace element abundance (primarily Mn, Fe, Mg and Sr), before five were ultimately selected for δ18O and δ13C analysis. The range in δ18O values suggest a ~7oC seasonal range in late Brigantian shallow sea water temperatures with average temperatures of ~20oC suggesting the onset of the Late Palaeozoic icehouse had begun prior to the latest Brigantian. Overall, this research shows the success of rapid colonisation mechanisms adopted by Gigantoproductus species at the study site, demonstrates the importance of a multi-phased preservation screening approach, highlights the heterogeneity in preservation of the biogenic shell material and contributes robust δ18O data for equatorial Brigantian waters to the literature.

The Karakoram mountains are situated at the western end of the trans- Himalayan Mountain belt. They are one of the most dynamically-active tectonic and geomorphic areas in the world. The valleys are among the deepest and hold some of the greatest thicknesses of Quaternary and recent valley fill sediments comprising glacial, debris flow, fluvial and aeolian sediments. These have been eroded to form terraces. Their development was controlled by tectonic and climatic factors, recording information about the last few million years of uplift and climatic changes. No simple relationship exists between terrace heights, degree of incision and terrace deformation, and the tectonic and climatic history of the area on the other. Allocyclic processes further complicate the interpretation of terrace formation. Several types of terraces have been differentiated and their sedimentology examined as follows. 1. Morainic terraces. The glacial system dominates with some of the longest glaciers outside the polar regions. These produce large deposits of till, dominantly of supraglacial meltout type. Three extensive glaciations have been recognised during Quaternary time and at least five minor advances during the Holocene. These produced extensive bodies of till scattered throughout the valleys: these have been used to reconstruct the extent and number of glaciations. 2. Glaciofluvial terraces Considerable thicknesses of glaciofluvial deposits infill small palaeovalleys typically of ice-contact facies reflecting deposition by high-gradient streams. Interbedded tills resedimented by debris flow processes are common. 3. Fluvial terraces These form a minor component and are common near the present river level. They were produced mainly by allocyclic processes related to the highly variable discharges of the glacially-fed rivers. 4. Debris terraces These widespread features were produced by failure of steep valley sides or by the resedimentation of debris, freqently till. Processes include debris flow, flowslide, rockslide, debris slide, rotational slide, creep, and slumps. 5. Lacustrine terraces Great thicknesses of silt were deposited rapidly in short-lived lakes. Incision produced terraces after the lakes drained. 6. Fan terraces These are polygenetic landforms comprising the sediments described above, but dominated by debris flow deposits of resedimented till. These formed early in the deglaciation of the area and represent a major phase of deposition which filled the valley bottoms. Fluvial aggradation and small mass movement processes modified their surfaces to produce typical fan geometries with varying surface gradients. Fan-head entrenchment and fan- toe truncation indicates that these are relic features. Tectonically deformed terraces are rare, but active faulting has been recognised near Rakhiot. Glaciotectonic processes, slope processes and dewatering may also deform terraces, and examples are described. Three planation surfaces were recognised and probably represent tectono-climatic cycles, punctuated by uplift and denudation in successive glaciations. A discordant drainage pattern reflects an early Karakoram structural grain modified by differential uplift of the Great Himalaya and the Nanga Parbat- Haramosh massif which produced the concordant drainage of the Indus River.