The volcanic centre of North Ruri is situated in the Kavirondo Rift Valley about 1 Km north of its counterpart, South Ruri. The complex, emplaced in updomed Pre-Cambrian Nyanzian metabasalt, consists of numerous steeply inclined of alvikite conesheets/which form short arcs in a much larger coneshaped structure. Smaller pipes and dykes of sSvite with plates of ferroan calcite, and ferruginous carbonatite also occur. The alvikite usually has rhombs of calcite, due both to micro- brecciation of the earlier sflvite and primary crystallisation. Further brecciation and recrystallisation may modify the textures. Associated carbonatitic volcanoclasts show phlogo-pitisation and feldspathisation due to reaction with the carbonatite's volatile constituents. Alkaline silicate rocks are represented by several intrusions of nepheline-microsyenite within the complex and numerous outlying plugs of phonolitic nephelinite, two of which contain biotite xenocrysts. Ijolite is widespread as xenoliths and fragments and is believed to underlie the whole complex. The matrix between the feldspar plates of the nepheline-microsyenite is essentially micro-ijolitic, and suggests that development of the interstitial orthoclase has occurred in the upper part of an ijolite mass. Limited fenitisation of the Nyanzian metabasalt by the adjacent nepheline-microsyenite has produced a narrow zone of alkali- syenite fenite. Blocks of augite-glimmerite, hornblende-pyroxenite and biotite-pyroxenite in the carbonatitic agglomerate indicate the presence of these rocks at depth. North Ruri is suggested to be later than the nearby Kisingiri complex of Miocene nephelinite lavas and agglomerates, which almost surround North Ruri and Okuge, on the relationship between the agglomerates and the phonolitic plugs of Ruri, Age determinations of the carbonatites also suggest a post-Miocene age. The much smaller complex of Okuge consists of a horseshoe shaped mass of carbonatite conesheets, with scattered outcrops of melanephelinite lava and agglomerate (from the Kisingiri Volcano), and phonolitic nephelinite lava surrounding it.

Current interpretation methods, research and field practice are reviewed, followed by a description of laboratory apparatus and methods for time and frequency domain measurements on samples and models, and a 300 watt time domain field unit. Time domain measurements on 69 samples indicate the following. The rate of change in polarizability with varying changing time or current density is greater for membrane than for metallic polarizers. The changing time behavior is significantly different and may be of diagnostic value. Fluvioglacial sands have similar I.P. properties to alluvial sands studied by other workers. A theoretical function given by Anderson and Keller (1964), relating polarizability and clay content of such sands is empirically verified. Serpentine and chlorite minerals in altered basic igneous rocks can give rise to large polarizabilities. Metallic polarizers rarely have R values in excess of 2.36 where R is the ratio of the 1 second and 5 second transient voltages, Membrane R values can exceed this figure but are also commonl lower. 94 scale model cases are presented. A number of empirical relationships useful for direct interpretation of gradient array polarizability anomalies are derived. They agree with analogous theoretical functions for simple charge configurations derived using elementary potential theory. These functions are equivalent to the magnetic case. It is demonstrated that direct techniques of total or vertical field interpretation can be applied. Scale model transient R values vary both from place to place over a body with a constant geometry of polarization, and with changing geometry of polarization. At the present sensitivity of I.P. field gear the method is not applicable to the field study of glacial deposits due to the lack of a widespread polarizing lithology. A scheme for the interpretation of multilayer resistivity and polarizability Wenner depth probes is given.

Ostracoda from the Upper Cretaceous and Lower Tertiary iron five wells in Saudi Arabia have been examined. The Superfamily Cytheracea is studied in detail. It is represented by seventy-five species. Of these, seventy-one are new, one has been established by Siddiqui (1971),one by Al-Furaih (1975) and two are left under open nomenclature. Six new genera - Clinocythere, Hapsicytherura, Holcopocythere, Phyrocythere, Rhostocythere and Schizoptocythere - and two new subgenera - Otarocythere and Prophalcocythere - are described. A modification of the Liebau diagram for the analysis of the ornament has been adopted. The Upper Cretaceous and Lower Tertiary formations from two wells (Abgaiq W-69 and El-Alat W-1) are divided into five ostracod biozones and a correlation with the previously established foraminiferal zonal scheme for the Umm er Radhuma Formation is discussed. All the evidence indicates that the Aruma and Umm er Radhuma Formations were deposited in a shallow water, mainly carbonate, environment.

The low-level (150 metres mean terrain clearance) aeromagnetic maps of Cyprus and the Biga peninsula, Turkey have been analysed to determine the structure and the location of the mineralized areas. The aeromagnetic data was digitized at 0.5 and 1.0 km intervals reduced to pole, filtered, continued upwards and downwards, and the second vertical derivative determined, all using programs written for the purpose. The resulting maps were broadly similar but the most useful was that resulting from the application of the Fuller 2-D filter (Fuller, 1967) whose pass-band characteristics could be adjusted as required. The magnetic properties of the main rock types were determined on cores in the laboratory using a PAR spinner magnetometer and a Sharpe SM4 susceptibility bridge. These were used in the interpretation of the filtered maps by using the methods of Talwani et al. (1964) and Koulomzine et al. (1970). In Cyprus, the positive anomalies were attributed to the Pillow Lavas which had a mean total magnetization of 9.0 x 10-3 e.m.u./cm3 in the direction 280°/42° down. The negative anomalies were attributed to the intrusive gabbros which had a mean total magnetization of 1.4 x 10-3 e.m.u./cm3 in the direction 300°/66° down. The "Sheeted Intrusive Complex" has a moderate total magnetization of 4.1 x 10-3 e.m.u./cm 3 in the direction 329°/56° down. The anomalies were therefore interpreted in terms of the Pillow Lavas of thicknesses varying up to 500 metres and variation in the depth to the gabbros. The trends of the magnetic anomalies reflect two main trends - NW and ENE of the mineralization which is believed to have originated from the gabbros The orebodies are usually located at the faulted zones in the Lower Pillow Lavas on the down-throwside and the aeromagnetic data could be used to assist in the location of these faults. Gossanized zones cap gabbroic intrusions which may have massive sulphides on the flanks where they intrude the Pillow Lavas and are indicated by negative anomalies. In the Biga peninsula, the magnetic anomalies are attributed to the granodiorites which have a mean total magnetization of 4.09 x 10-3 e.m.u./cm 3 in the direction 344°/60° down. The granodiorites intrude a metamorphic basement series which is faulted into a series of NE-SW striking horsts and grabens and this is reflected in the trending of the magnetic anomalies. The magnetic interpretation shows that there is a deep basinal area extending to the Sea of Marmara northeastwards from the Bay of Edremit with maximum depth of 5 km. The principal orebodies are hydrothermal originating from the granodiorites and are found in the basement. The aeromagnetic data may therefore be used to locate underground granodiorite cupolas around which mineralization may exist.

No description available.

Detailed geochemical studies of the dispersion patterns of selected elements (Cu, Pb, Zn, Ag, Mn, As, Fe, Ni, Co) were undertaken in the drainage sediments and soils in the Lavrion peninsula with the objective of demonstrating the application of geochemical techniques to the search for previously unknown mineral deposits. The study area comprises three geological units; the Anavissos, Kamareza and Plaka, each with its distinct stratigraphy and structural history. The Kamareza and Anavissos units are separated by the Legraina fault, while the overlying Plaka unit is separated from these underlying two units by an unconformity. Both geological and geochemical data indicate that karstic mixed sulphide mineralization is largely restricted in the Kamareza and Plaka units. An area of approximately 65 square kilometres was chosen for detailed stream sediment, soil, rock and bigeochemical studies. Digestion of 0.2 gms. Of minus 80-mesh material in 25% (HNO3 at 90°C) for 4 hours appeared to provide the optimum technique for dissolution of elements such as Cu, Pb, Zn, Mn, Fe and Ni. Analysis was performed by AAS for all these elements. Arsenic was also determined by the cold extraction method (James, 1957). The data obtained were treated by graphical, univariate and multivariate statistical techniques including histograms, bar-diagrams, graphs, frequency distribution analysis, moving averages, correlation coefficient, factor and regression analysis. Other properties including pH, conductivity, organic matter content and CaCO3, and both Fe-and Mn-oxide concentrations, were also investigated in order to establish their influence on the distribution patters of the various elements. It was demonstrated that within the study area mechanical dispersion dominates over chemical. In spite of contamination from extensive past mining activity, geochemical stream and soil surveys produce reliable distribution patterns in the Mediterranean environment of Lavrion. The occurrence of previously unknown mineralization was proven by trenching in target areas indicated by geochemical patterns. Biochemical surveys were also found to yield useful information, although they are time consuming and suffer from problems associated with the uneven distribution of plant species.

The project aims to describe the geology and hydrothermal fluid evolution of mineral deposits of the Gumusler area in the Nigde massif. Two types of deposits can be differentiated in this area: Sb Hg W Ba Au veins and associated replacement type Ba- Sb mineralization at the Rasih-Ihsan deposit, and a breccia hosted Hg Sb Au prospect at the Mehmetler Yurdu Sivrisi Tepe (MYST). The vein deposits are localized along E-W trending and N-dipping faults in marbles, and along marble-gneiss contacts. There is a spatial relationship between the mineral deposits and the felsic dykes of Cenomanian age which are cut by tlie Sb-Hg- W Ba vein. Similar dykes, together with intensive fracturing of marbles along the gneiss- marble contacts, also contributed to the formation of approximately E-W trending breccias containing the Hg Sb Au prospect at the MYST area. The Gumusler deposits have a diverse mineralogy including scheelite, barite, stibnite, cinnabar, sulphosalts and gold. Gold is associated with the cinnabar deposition stage, and is locally enriched in near surface zones with concentrations as high as 37 ppm at the MYST prospect. Silicification is the dominant wall rock alteration at the mineralized locations but sericitization, kaolinization, dolomitization and tourmalinization also occur at the periphery of the mineralization. Mineral deposition took place from aqueous fluids over a wide temperature range ( 350 °C to 150 °C). The pre-sulphide alteration (tourmalinization) occurred from fairly saline (8 2.5 eq. wt % NaCl) and moderately high temperature (216-254 °C) fluids. The main barite deposition also took place from fairly saline (8 2.5 eq. wt % NaCl) fluids at temperatures of 149-213 °C which are diluted towards the stibnite stage with a salinity of 4 eq. wt % NaCl and a temperature range of 137-168 °C. This probably indicates increasing involvement of non-magmatic waters. delta34S values of pyrite and stibnite range from -4.3 to +2.2 ‰ whereas those of barite are ~18 %, which suggests a magmatic origin for the sulphur of both sulphide and sulphate. Tourmaline mineral chemistry of hydrothermal alteration zones indicates a mixture of granitic and metapelitic sources, but comparison with tourmalines of other magmatic deposits favours a magmatic origin for boron.

IgA nephropathy (IgAN) is a common glomerulonephritis characterised by deposition of IgA1 in the glomerular mesangium The underlying abnormality lies within the IgA system rather than the kidney, and modest irregularities of IgA biology have been described, but the mechanisms involved in IgA1 deposition and glomerular injury remain elusive. A few reports have suggested an abnormality of the carbohydrate component of IgA1 in IgAN. These studies sought to confirm and further characterise the putative glycosylation defect and to identify its biochemical basis. Lectin binding assays were developed and used to analyse the N- and O-linked glycans of IgA1 in IgAN and controls. No gross abnormality of N-glycosylation was detected in IgAN, though these studies were subject to technical limitations. IgA1 in IgAN displayed significantly increased binding to lectins with affinity for O-linked N-acetylgalactosamine (Ga1NAc) as compared to controls. One explanation for this finding is reduced terminal galactosylation of the O-linked sugars of IgA1. A novel assay was developed to measure the functional activity of alpha1,3 galactosyltransferase (alpha1,3GT), the enzyme responsible for O-galactosylation, in cell lysates. In IgAN, peripheral blood B cells appeared to show significantly lower alpha1,3GT activity than controls, and this was inversely proportional to Ga1NAc expression of serum IgA1 as measured by lectin binding. These studies confirm an abnormality of O-linked glycosylation of serum IgA1 in IgAN, which may be attributed to low B cell alpha1,3GT activity. Altered O-glycosylation of IgA1 may be relevant to the pathogenesis of IgAN.

The Sulaiman Range is located on the northwest margin of the Indian Plate. It forms the middle part of the Indus basin, and has been termed the Sulaiman sub-basin. The Indus basin is filled with a thick sequence of Mesozoic and Cenozoic sediments. The Dungan Formation is Palaeocene in age and comprises a 98 m thick predominantly carbonate sequence which extends about 200 km from north to south along the Sulaiman Range. The Formation is characterised by different microfacies. Petrographic studies revealed the following microfacies; peritidal carbonate, inner lagoon, oolitic, outer lagoon, rhodolith platform, nummulitic, larger foraminiferal, and planktonic foraminiferal. All these facies can be interpreted broadly within a homoclinal, windward carbonate ramp model. The cementation history has been investigated by petrography of stained thin sections, cathodoluminescence microscopy, XRD, electron microprobe, SEM (in back scattered mode), XRF, and carbon and oxygen stable isotope analysis to reveal trace element contents and their variation in the diagenetic cements. The diagenesis of the formation starts from the marine phreatic environment, characterised by micritization and peloidal cements. These cements are of high Mg-calcite, and low in Fe and Mn. They do not show luminescence. The active fresh water phreatic zone may involve leaching in the zone of solution, neomorphism, isopachous bladed cement around the oolites and foraminifera, syntaxial overgrowth cement on echinoderm fragments, and interlocking crystals of equant calcite that coarsen towards the pore centres (drusy cement). The neomorphic spars having irregular boundaries and are cloudy and patchy. They are also low in Fe and Mn, and non-luminescent. The isopachous bladed cements are low in Mg and high in Fe and Mn and show orange luminescence. The syntaxial overgrowth cements are low Mg-calcite. They show bright zoned luminescence, indicating different zones of Fe and Mn concentration. The drusy cement is also low Mg-calcite, and shows dull to orange luminescence indicating the high concentrations of Fe and Mn as compared to marine cement. The oxygen isotopic values of this cement type are low when compared to the whole rock. Vug and mould porosities are developed in the freshwater vadose zone, which are filled by sparry calcite cement. The shallow burial environment is marked by compaction of skeletal grains, stylolites and fractures. The fractures show two generations. The early fracture fills cements are non ferroan and show bright zoned luminescence. The later fracture fills cements are ferroan and non-luminescent. The oxygen isotope values of non-ferroan cement filling fractures are more negative when compared with that of ferroan cement filling fractures, which may be formed in shallow burial environments by formation water.

The history of uplift, volcanism and faulting, and past geophysical studies suggest that extension in the Kenya Rift is actively driven by an upwelling thermal anomaly. The KRISP 94 experiment included a 440 km seismic refraction profile in southern Kenya to investigate the deep structure of the rift, 150 km east of the exposed boundary between the Archean Nyanza craton and the Proterozoic Mozambique orogenic belt. Combined travel-time and gravity interpretations produce an integrated crustal and upper mantle model, showing extensive thrusting of the mobile-belt over the cratonic margin. The rift itself has developed above the buried suture between these units. The asymmetric rift basin (filled with low velocity lavas or sediments) has a maximum depth of 4 km adjacent to the western bounding fault. The high velocity (7.0-7.2 kms-1) lowest crustal layer is modified beneath the rift, possibly by the addition of cumulate layers (products of fractional crystallization). A small amount of crustal thinning (1-2 km) directly beneath the rift axis suggests a pure-shear mechanism at depth. Minimum crustal extension is 4 km, but could be up to 10 km if the whole of the lowest crustal layer is a new magmatic addition. A long-wavelength regional gravity trend is consistent with the presence of a mantle plume beneath the craton to the west. A study of local earthquakes in Tanzania shows that the rift is propagating southwards along the craton margin. Many deep earthquakes (> 20 km) suggest cooler crustal temperatures than in Kenya, and preliminary travel-time tomography shows only minor crustal velocity variations. The results are consistent with rifting in Kenya being driven by an upwelling diapir, originating from a mantle plume beneath the craton. As it has spread, the diapir has been focussed along the suture between the Archean and Proterozoic units, but has not yet produced extensive crustal modification of the youngest part of the rift in Tanzania.