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Combined Pb, Sr and Nd isotope determinations on several Nigerian Mesozoic ( 170 Ma) ring complexes, studied previously by van Breemen and co-workers, indicate a multistage petrogenetic process. Mantle-derived differentiated magmas assimilated crustal basement of average Early Proterozoic age. After crystallisation, some plutons were subjected to a second stage of crustal contamination by circulating hydrothermal fluids. Crustal compositions were constrained by isotopic analysis of the Proterozoic basement of the Jos Plateau. Sm/Nd analysis of six gneisses yielded an average crustal residence age of 2 Ga, corresponding to the Burkinian event recognised elsewhere in western Africa. However, one sample yields a model age of 3 Ga, suggesting the presence of Archean crustal remnants. Pan-African granitoids yield a similar range of Nd model ages to the gneisses, suggesting that they were largely generated by crustal melting. The Zaranda anorogenic complex has relatively radiogenic initial Nd and Pb isotope compositions and unradiogenic Sr ( 0.5126,18.4 and 0.705, respectively), attributed to a mantle-derived differentiated magma which suffered moderate contamination during ascent through the crust. Other ring complexes trend toward less radiogenic Nd and Pb isotope ratios and more radiogenic Sr, indicative of an increasing crustal contribution. Initial Pb isotope compositions yield a well-defined Pb/Pb isotope array with a slope age of1.8 Ga which is consistent with the average Nd crustal residence ages of basement gneisses and granitoids. The arfvedsonite albite apogranite from the Ririwai anorogenic complex has isotope ratios resembling Pan-African basement, probably resulting from hydrothermal overprinting with fluids equilibrated in the continental crust. Other Ririwai intrusions and one unit from the Shere Hills display evidence of hydrothermal overprinting of Sr and to some extent Nd isotope compositions, but only the Ririwai apogranite has been significantly overprinted by hydrothermal Pb. The isotopic evidence supports a model for the Mesozoic anorogenic (“A-type”) granites of Nigeria in which mantlederived magmas suffered crustal contamination during magmatic differentiation to syenitic compositions, followed by sub-solidus hydrothermal alteration in the continental crust.

It is difficult to convey the accelerating rate and growing importance of mass spectrometry applications to human blood proteins and peptides. Mass spectrometry can rapidly detect and identify the ionizable peptides from the proteins in a simple mixture and reveal many of their post-translational modifications. However, blood is a complex mixture that may contain many proteins first expressed in cells and tissues. The complete analysis of blood proteins is a daunting task that will rely on a wide range of disciplines from physics, chemistry, biochemistry, genetics, electromagnetic instrumentation, mathematics and computation. Therefore the comprehensive discovery and analysis of blood proteins will rank among the great technical challenges and require the cumulative sum of many of mankind's scientific achievements together. A variety of methods have been used to fractionate, analyze and identify proteins from blood, each yielding a small piece of the whole and throwing the great size of the task into sharp relief. The approaches attempted to date clearly indicate that enumerating the proteins and peptides of blood can be accomplished. There is no doubt that the mass spectrometry of blood will be crucial to the discovery and analysis of proteins, enzyme activities, and post-translational processes that underlay the mechanisms of disease. At present both discovery and quantification of proteins from blood are commonly reaching sensitivities of ∼1 ng/mL.

Field observations, petrological interpretations combined with cationic geochemical data and diagrams illustrate the magmatic and postmagmatic events in the Mesozoic anorogenic complexes of northern Namibia. The magmatic lineage of the Damaraland alkaline centres is cationically defined in a modified Q–P diagram (Debon and Le Fort 1988). Major element concentrations for Brandberg and Erongo supported by chemical data from other Damaraland complexes at Cape Cross, Otjihorongo, Messum, Spitzkoppies, and Paresis, have been converted to millications, to delineate a magmatic lineage which follows an alkaline oversaturated trend. Superimposed on this magmatic lineage is textural and geochemical evidence for hydrothermal metasomatic disequilibrium and partial re-equilibration. Volcanic rocks and their granitic equivalents from the Erongo complex show petrological and geochemical criteria indicating substantial potash and boron metasomatism which has given the Erongo rocks a subalkaline potassic geochemical signature. Similar granite compositional trends are also recorded within the Brandberg massif. However, at Brandberg, there is a later-stage hydrothermal overprint generating a texturally variable peralkaline granite, with spectacular examples of linear zones of aegirine and arfvedsonite apparently constrained to microfractures in marginal granite sheets. The zones of mineral ‘layering’ can be divided into three repetitive units and traced horizontally along the southwestern margin of the Brandberg massif for a distance of 3 km and vertically for 200–300m. These marginal rocks are cross-cut by dykes and sheets of brandbergite, a mesocratic fine-grained peralkaline rock. Fenite veins, described elsewhere from marginal zones of strongly alkaline massifs, are found near the inner brecciated contact zone with the main granitic mass of the Brandberg. These fenite veins are interpreted as fluid-channel ways along which mass transfer of peralkaline components occurred during the final stages of cooling and consolidation.

In late 1988 and 1989, the author led a seven country study of NGO activities for the Asian Development Bank. Almost twenty consultants from eight different organizations were involved in the project, the purpose of which was to identify NGOs that were able to contribute to Bank financed projects, and the ways in which any collaboration could take place. The willingness of governments to support the projects was an important aspect of the assessment. During the course of the study, a number of features of NGO operations were identified which are not often reviewed in the literature. These issues, discussed in this paper, relate to the mutual benefits that would flow from greater levels of co-operation between large donors and NGOs. The paper also discusses some of the difficulties that stand in the way.

The ankle is often considered to have little or no capacity to move in the transverse plane. This is clear in the persistent concept that it is the role of the subtalar joint to accommodate the transverse plane motion of the leg while the foot remains in a fixed transverse plane position on the floor. We present data from noninvasive in vivo study of the ankle subtalar complex during standing internal and external rotation of the leg and study of the ankle subtalar complex during walking. These data reinforce the results of cadaver study and invasive in vivo study of the ankle/subtalar complex. We suggest that the ankle is capable of considerable movement in the transverse plane (generally greater than 15 degrees) and that its role in the mechanism that allows the foot to remain in a fixed transverse plane position on the floor while the leg rotates in the transverse plane, is not simply the transfer of the transverse plane moment to the subtalar joint, but is accommodation of some of the necessary movement.

Protein biomarkers offer major benefits for diagnosis and monitoring of disease processes. Recent advances in protein mass spectrometry make it feasible to use this very sensitive technology to detect and quantify proteins in blood. To explore the potential of blood biomarkers, we conducted a thorough review to evaluate the reliability of data in the literature and to determine the spectrum of proteins reported to exist in blood with a goal of creating a Federated Database of Blood Proteins (FDBP). A unique feature of our approach is the use of a SQL database for all of the peptide data; the power of the SQL database combined with standard informatic algorithms such as BLASTand the statistical analysis system (SAS) allowed the rapid annotation and analysis of the database without the need to create special programs to manage the data. Our mathematical analysis and review shows that in addition to the usual secreted proteins found in blood, there are many reports of intracellular proteins and good agreement on transcription factors, DNA remodelling factors in addition to cellular receptors and their signal transduction enzymes. Overall, we have catalogued about 12,130 proteins identified by at least one unique peptide, and of these 3858 have 3 or more peptide correlations. The FDBP with annotations should facilitate testing blood for specific disease biomarkers.

Most of the African continent consists of various terranes of different Precambrian ages accreted during major orogenies. It is not surprising therefore that the ages and orogenic events throughout Africa cannot always be correlated within the current configuration of the African continent. The Pan-African orogeny in the late Proterozoic played a major role in re-assembling old cratons and terranes to form the supercontinent Pangaea and its southern extremity, Gondwanaland. It was into this basement that the Phanerozoic plutonic complexes were emplaced. As a result of terrane accretion the mineralizing potential of each terrane as a possible source for ore metals must be considerably variable, and perhaps account for part of the irregular distribution of mineralized Phanerozoic complexes on the African plate.

A series of overlapping ring structures each contain varied, pre-caldera volcanic sequences, overlain by massive intra-caldera rhyolitic ignimbrites and enclosed within ring dykes of fayalite-hedenbergite granite-porphyry. Early basalts are hypersthene-normative but may originally have been alkaline or transitional to nepheline-normative. They are linked, through a series of andesine basalts, mugearites and trachyandesites, to aphyric trachytes. Pre-caldera rhyolitic rocks, interbedded with and overlying the basic and intermediate volcanics, are mainly ignimbrites which were perhaps originally peralkaline or near peralkaline, but are often recrystallized to subalkaline compositions. They formed mainly through partial melting with zone refining of crustal rocks, the mantle-derived basic to intermediate magmas providing the heat source. In the early stages of each caldera-forming cycle the ignimbrite eruptions were of small volume and the rocks have varied crystal contents. Later, large high level magma chambers must have developed, from which crystal-rich ignimbrites with volumes in the order of 100 km 3 were erupted, with accompanying caldera collapse. The form of the complex as a whole shows that this cycle occurred repeatedly, but with the location of magma generation migrating progressively westwards, resulting in a chain of rhyolitic cauldrons, into which subvolcanic granites and syenites have been emplaced.

The Streckeisen QAP diagram discriminates four characteristic type series among the large variety of granitoids associated in intrusions. Three of them integrate varied compositions from basic to acid terms: (1) the calcalkaline series with its low K (or trondhiemite), medium K (or granodioritic), high K (or monzonitic) variants; (2) the alkaline series with its characteristic syenitic members; (3) the tholeiitic series, deprived of K feldspars. The fourth (4) corresponds to mobilizates associated with migmatites of varied composition but always quartz rich. The generalization in the QAPF system, allowing the plotting of undersaturated alkaline series, provides an excellent visual display of the major associations and trends for the plutonic rocks.

Sixty-four Rb-Sr and two K-Ar isotopic measurements from seven ring complexes in central Nigeria provide evidence for a systematic age trend along a 200 km zone ranging from 174±5 m.y. in the north to 154±4 m.y. in the south. A peak of anorogenic magmatism occurred in the Jos Plateau region about 164±4 m.y. ago. Although a small syenitetrachyte complex at Zaranda, near Bauchi, gives an age of 190±15 m.y., unpublished ages of 290–330 m.y. for the southern Niger ring complexes confirm the existence of an overall southerly decreasing age trend in the Niger-Nigeria province of West Africa.

The close of the Pan-African was characterized by a change from subduction and arc related magmatism to post tectonic alkaline magmatism in Saudi Arabia and West Africa. For the remainder of the Phanerozoic, folding and tectonism was more restricted in Africa than on any other continent and was limited to the Caledonian, Hercynian and Alpine orogenies in the extreme north, and the Cape fold belt at the southern tip of the continent, with an equivalent orogenic belt on the extreme east of the Arabian peninsula. Thus Phanerozoic magmatism was dominantly anorogenic in nature and alkaline in character throughout the African Plate. Such magmatism was initiated by reactivation of deep-seated lineaments with the peak of activity during the Mesozoic, which can be correlated with fragmentation of Gondwanaland. The Phanerozoic alkaline magmatism is characterised by small centres of subvolanic to plutonic nature often in the form of ring complexes. These can be subdivided into two separate associations consisting of Provinces dominated by centres of oversaturated magmatism such as Nigeria and Sudan. There are also provinces with undersaturated complexes and carbonatites with oversaturated magmatism such as in Namibia, Angola, and the East African rift system. Despite the contrasting nature of undersaturated and oversaturated magmatism many comparisons can be drawn between carbonatites and granitic complexes. Such comparisons include the source of the magmas, the mechanisms of emplacement, the cause and effect of alkali metasomatism and processes of hydrothermal alteration, the trace element geochemistry, the abundance of zircon, uranium, thorium and complex Ti-Zr silicates, the importance of columbite, pyrochlore, fluorine, and rare earth enrichment in mineralization, and in their current and future economic potential. The common feature is the development and reactivation of deep-seated lineaments which were not only controlled the emplacement of anorogenic complexes but also acted as channelways for hydrothermal mineralizing fluids. The development of a fluid phase during crystallisation occurred in both undersaturated and oversaturated alkaline rocks. Subsequent hydrothermal modifications, subsolidus reactions, geochemical variations and mineralization were dependent upon whether this fluid phase was retained or expelled.

Forty Rb-Sr isotopic measurements on minerals and whole rock samples from 11 anorogenic complexes in northern Nigeria complement the evidence for systematic age variations along a series of en-echelon ENE-WSW and N-S lineaments following two major fracture directions of extensional deformation in the Precambrian basement. The new ages presented in this paper confirm our earlier discoveries of a general southerly age trend but substantiate for the first time that major local migrations of magmatic activity were concentrated along at least two ENE-WSW zones. From the overlap in analytical error, the age patterns also suggest that contemporaneous anorogenic magmatism may have been locally derived from several simultaneous high-level magma chambers connected to a common deeper source. Different models that have been proposed for the origin of linear mid-plate magmatic activity are critically reviewed. In our opinion magma generation was most likely initiated in the asthenosphere-lithosphere decoupling zone or...

Twenty-nine Rb-Sr whole-rock isotopic analyses and three U-Pb zircon analyses on foliated granites and largely unfoliated charnockitic rocks indicate that the central part of the Pan-African belt in west Africa was characterised by intense orogenic plutonism. These data and Rb-Sr analyses on muscovite books from late cross-cutting pegmatites indicate that the peak of magmatic activity occurred 610 ± 10 m.y. ago. Initial 87 Sr/ 86 Sr ratios for the granitic and charnockitic rocks are in the range 0.7065–0.7125, and indicate a significantly older crustal component in the magmas.

In Niger, uranium occurs in upper Palaeozoic and lower Mesozoic continental sedimentary basins west of the Aïr mountains, but the source of the uranium had not been identified. Geochemical studies and fissiontrack observations on alkaline ignimbrites preserved in two Palaeozoic anorogenic centres in Aïr show that uranium is concentrated in the matrix and on secondary iron-oxide coatings surrounding lithic and crystal fragments. Based on variable Th/U ratios and degree of oxidation, it is concluded that the original ignimbrite field was enriched in uranium, but that a considerable proportion was leached during the weathering of the volcanic pile. Tectonic uplift, anorogenic magmatism, followed by weathering and erosion of the volcanic cover, with sedimentation in nearby continental basins, have all contributed to the development of uranium mineralization in Niger. The petrological and geochemical similarities between the Palaeozoic ring complexes in Niger and the Nigerian Mesozoic ring structures suggest that sedimentary uranium deposits may also be found in Nigeria if the tectonic and sedimentological controls were favourable.Enriched concentrations of uranium have been discovered in the exposed granitic roof zones of the Nigerian subvolcanic centres, with Th/U ratios approaching unity. Thus local vein deposits of uraninite, as well as dispersed uranium in recent sedimentary horizons, could be discovered particularly in the drainage systems entering the Chad Basin.

Two series of granitoids are present in the Finisterre region. One is formed mainly by syn-collision two-mica leucogranites. The other is composed of syn- and post-collision granodiorites and monzogranites of calc-alkaline affinity. The emplacement of these granitoids took place during and after the main phases of regional deformation. Petrographic and geochemical studies on the leucogranites suggests a common crustal origin with the surrounding metamorphic series, which includes metasediments and orthogneisses of medium to high grade amphibolite facies. The syn- and post-collision "calc-alkaline" series is associated with basic to intermediate rocks, suggesting a lower crustal origin. REE data have been used to characterize the two types of granitoids and to model the source areas of generation. There is no evidence for an origin of the granitoids by melting of mantle-type igneous rocks. Instead, the sequences of granitoids can be explained assuming different degrees of partial melting from a heterogeneo...

Carbonatites are defined as igneous rocks containing more than 50% carbonate minerals. They are divided into four classes: (1) calcic, (2) dolomitic, (3) ferrocarbonatite, and (4) natrocarbonatite. Carbonatites are characteristically associated with ijolites, but not all carbonatites are entirely magmatic. Many centres show metasomatic replacement features, referred to as fenitization. Most subvolcanic and volcanic carbonatite centres are calcic, but trapped fluids as inclusions in apatite crystals indicate that the bulk composition was alkalic and chemically comparable to natrocarbonatite. Experimental evidence suggests that parental carbonatite magma is the product of immiscibility from an alkali silicate liquid of phonolitic or nephelinitic composition. Alkali loss from the bulk carbonatite magma caused fenitization represented by zones of sodic and potassic metasomatism. Sodic metasomatism is more frequently located at deeper eroded centres and is characterized by the occurrence of albitite. Potassic metasomatism is more common in many carbonatite centres and is represented mineralogically by alkali feldspar and phlogopite. Many fenites carry an alkaline ferromagnesian assemblage consisting principally of alkali amphibole (eckermannite-magnesioarfvedsonite) and/or aegirine. Carbonatites have igneous isotopic ratios and distinctive contents of incompatible trace elements. Associated fenites have elevated Sr isotopic ratios and selected TE enrichment pertinent to the dominant metasomatism. Carbonatites exhibit REE, Nb, U, Th mineralization and, more rarely, sphalerite, galena, and chalcopyrite mineralization. Both disseminated and vein-controlled mineralization are found in many carbonatite centres. The most important economic products of carbonatites include pyrochore, columbite, monozite, apatite and zirconium minerals. The alkaline syenites and alkaline granites as ring complexes have textural, petrological and chemical characteristics which are distinctly different from I and S type granitoids. The characteristics of A-type granites are dominated by the separation of an (immiscible?) fluid phase which caused limited sodic and potassic metasomatism. Greisenization by acid metasomatism has played a critical role in several anorogenic provinces producing important UNb, ZnSn mineralization. In the fayalite granites, ferrohedenbergite breaks down to sodic-calcic amphibole as iron-rich olivine is destabilized under the influence of the fluid phase. Facies with aegirine and arfvedsonite can develop to give peralkaline granites. Relative loss of the peralkaline fluid phase results in the development of peraluminous biotite granites. The most significant chemical feature of anorogenic granites is that slight differences in the proportions of Na, K and Al can produce striking changes in the mineralogy of the A-type suite. The most characteristic feature of peralkaline granites is the anomalous enrichment in Zr, Zn, Nb, Y, Th, U, LREE, HREE, coupled with high Rb/Sr ratios. Some of these features are found in biotite granites but with dramatically less Zr, Hf, Nb and HREE. The primary mantle origin of syenitic magmas parental to intraplate alkalien granites is well established from isotope studies. The role of the continental crust is implemented by elevated initial 87Sr/86Sr ratios. The lower crust in Africa is thought to be lower Proterozoic in age from NdSrPb isotopic data. Fenitization is not only associated with carbonatite centres but also to a limited extent with alkaline granites. The evolution and separation of a peralkaline fluid phase from A-type granites has been experimentally demonstrated, and can be recorded by distinctive suites of subsolidus minerals and specific geochemical changes. From the mineralization viewpoint there are many parallels with the carbonatites, particularly with the abundance of sphalerite, rare-earth minerals, zircon and complex titanium-zirconyl silicates, uranium and thorium, columbite and pyrochlore. Such a distinctive alkaline mineralization suite, possibly related to an alkali carbonate fluid phase, is superimposed on a more normal, less alkaline group of ore minerals such as cassiterite, wolframite, chalcopyrite, and galena.

Granitoid rock compositions from a range of tectonic environments are plotted on a multicationic diagram devised by de la Roche and his coworkers. This shows that there is a systematic change through an orogenic cycle which leads progressively to the ultimate development of alkaline magmas. Possible source materials and mechanisms of magma generation are considered from analysis of mineral compositional vectors. These suggest that most granitoid series result from a two-stage process. First, fractional crystallisation of clinopyroxene, olivine and calcic plagioclase from a basic source with tholeiitic affinities produces a magma of intermediate composition. This magma then undergoes periodic mixing with a felsic magma followed by in situ fractionation to generate individual intrusions within granitoid series.

The Nigerian younger granites, as well as the petrologically similar but chronologically older northern centres in Air and south Niger, constitute the best example of epidosically migrating mid-plate magmatism. The Nigerian anorogenic ring complexes provide a classic example of alkaline granitoid evolution. Each anorogenic centre represents the exposed roots of an eroded volcano. Volcanic assemblages preserved by caldera collapse at some centres confirm that early erupted liquids evolved from olivine basalt through hawaiite, mugearite and trachyte. Although there are volumetrically abundant rhyolitic ignimbrites, there are no volcanic equivalents of biotite granite. However, at the subvolcanic level biotite granites are extensively mineralized with rich deposits of columbite, sphalerite, cassiterite and wolframite. Related peralkaline granites contain enriched concentrations of ore elements but apart from pyrochlore, thorium-rich monazite, and topaz, most potential ores are contained in alkali amphiboles or alkali pyroxene. Fluid interaction in the granite cupolas has caused subsolidus mineral growth and modified original element abundances. In some instances fluid reaction has been so intense that original granite has been locally converted to albite, microclinite, and greisen. These reactions can be monitored by the new mineral assemblages, the major element chemistry, trace elements (e.g., the rare earths) and isotopically by the initial strontium isotopic ratios.

Nine rare earths have been determined by Instrumental Neutron Activation Analysis (INAA) in syenites and related granitic rocks from the Nigerian younger granite (Mesozoic) Province. The majority of the granites contain dispersed UNb and vein-controlled ZnSn mineralization. It is inferred from a study of the chondrite-normalized rare-earth patterns that europium depletion in alkaline and sub-alkaline mineralized granites appears to be not just related to magmatic processes but also to hydrothermal changes induced during sub-solidus recrystallization.

SUMMARY The paper examines a number of empirical studies which investigate the implementation problems that have been experienced in Third World countries. Most of these studies are evaluation studies, specifically undertaken in order to identify the type and frequency with which implementation problems were being experienced. Only one of the studies is countryspecific (Indonesia), drawing its data directly from the problem-reporting component of the national monitoring system, although emompassing a sufficiently large number of projects for some general conclusions to be drawn. The paper finds that about half of the implementation difficulties experienced in Third World projects or programmes arise through the procedures and operating methods of central ministries other than the implementing ministry. The key ministries are principally planning, finance and personnel. Concentration by Third World governments on strengthening the central procedures under which all projects operate, therefore, is likely to have a disproportionately high impact on the implementation of development programmes. Suggestions for obtaining this improvement conclude the paper.

Problem‐oriented training (POT) requires considerable skill from a trainer with wide experience in identifying the optimum training approaches for resolving management issues and the ability to convince managers throughout the organisation that improvement and change are feasible. It draws on the collective goodwill and enthusiasm that a competent trainer can generate. Examples of the use of POT in telecommunications, a government agency and by an aerospace contractor are given.

The significance of rare earth distribution patterns in trace element geochemistry is briefly reviewed. Established methods for their determination at the Reactor Centre by instrumental and radiochemical techniques are described, and examples of recent applications discussed.

A study of selected rare earths, determined by non-destructive neutron activation analysis, in six Nigerian younger granites, together with previously publisded data on similar granites from northern Nigeria and Russia, reveals that anorogenic granites with peralkaline affinities develop an enrichment in the middle rare-earth group Sm, Gd, Tb and Dy with a corresponding Eu depletion. Such patterns may be related to the precipitation of earlier formed perthitic feldspar and late crystallizing alkaline amphibole from low temperature liquids enriched in volatiles (alkalis and fluorine). Progressively albitized peralkaline riebeckite granites exhibit rare earth enrichments towards Yb until the most albitized peralkaline granite is no longer depleted in Eu and there is a marked upward curvature of the relatively heavier rare-earth patterns. This change could be caused by residual albite-rich hydrothermal fluids which overprinted the earlier rare-earth distribution patterns.

The radioactivity induced in rock slices during fission track analysis for uranium can usefully be employed in instrumental neutron activation analysis for determination of major and trace element distributions in the sample using a collimated gamma spectrometer. A description is given of the application of particle track techniques in conjunction with activation analysis to a geochemical study of element migration in a sample of mineralized granite from Nigeria. The study indicates that U is enriched during the earlier period of rock-fluid interaction (microclinization) and that Th is enriched during greisenization.

The similarity of the lead isotopic composition in older granites, pegmatites and the younger granites, together with the distribution of tin and the absence of tourmaline in the Mesozoic ring-complexes, are utilised as evidence to establish that the Nigerian younger granites were derived from an initial peralkaline melt by fusion of local ‘basement’ rocks. It is also suggested that the associated metaluminous trend is caused simply by more complete melting, and that peraluminous granites developed during subsequent cooling. When feldspar normative compositions of younger granites are plotted in the quartz-saturated ternary feldspar system (James and Hamilton, 1969), they support a cyclic event of fusion and cooling to account for the variation in rock-type. The actual source material has not been established but it could be similar to bauchite, a quartz-fayalite monzonite, which was melted by a linear zone of high heat flow from the mantle during the disruption of Gondwanaland.

The distribution of lithium, which has been determined in 48 Nigerian Younger Granites, ranges from less than 5 ppm in an amphibole-granite to a maximum of 630 ppm in albite-riebeckite-granite. The lithium concentration does not exceed 60 ppm for the amphibole-granites, but higher values, greater than 100 ppm, are obtained in the tin-bearing biotite-granites. The Fe 2+ Li ratio and K Rb ratio ( Butler et al., 1962) decrease sympathetically in the later-formed rocks. The distribution of lithium and fluorine, particularly in the riebeckite-granites, shows a statistically “significant” positive correlation. This association suggests that the higher lithium values were probably introduced by late-magmatic and post-magmatic processes. Satisfactory correlation coefficients are also obtained for lithium and rubidium (r = +0.905) and between lithium and thallium (r = +0.457). The rare alkali data for the Liruei complex indicates that both lithium and thallium increase in the two trends; amphibole-granites → biotite-granites, and amphibole-granites → riebeckite-granites ( Bowden , 1964).

Partial melting experiments on Nigerian charnockitic monzonite associated with migmatised gneisses provide consanguineous liquids from which the metaluminous and peraluminous younger granites may be derived. After 40–60% melting at 750–800° C the liquids are metaluminous with hastingsite-fayalite granite affinities. On cooling towards the granite system minimum these liquids can evolve into metaluminous hastingsite-biotite granite and peraluminous biotite granite compositions. These experiments show that partial melting of charnockitic monzonites cannot yield peralkaline liquids at the specified conditions (750–850° C).

From 1960 to August, 1966, the activity of Oldoinyo Lengai took the form of quiet extrusion of carbonatite lava. In August, 1966, the style of activity changed abruptly and violent ash eruptions took place. The activity varied from minor emissions of ash to major Plinian and Vulcanian type eruptions. A new ash-cone built up within the crater and ash was widely distributed on the slopes of the volcano and over the surrounding countryside. The ash consists of sodium carbonate mixed with crystals of nepheline, pyroxene, wollastonite, apatite, melanite and pyrite. Also blocks of ijolite and melteigite were ejected during the activity.

The zirconium content of 48 Nigerian Younger Granites has been determined by X-ray fluorescence spectrography. Values range from 110–420 ppm in the biotite-granites to a maximum of 2200 ppm in albite-riebeckite-granite. In the amphibole-granites (220–1500 ppm) high values are usually associated with rocks containing arfvedsonite, while lower values may be correlated with the presence of ferrohastingsite. The zirconium distribution is partly reflected by the relative abundance of zircons in the amphibole-granites and their paucity in the biotite-granites. In contrast, the riebeckite-granites contain high zirconium values but zircons are relatively rare. The distribution of zirconium is dependent on the alkalinity of the various melts from which the rock phases crystallized. The changing alkalinity conditions are interpreted from the variation in the agpaitic coefficient (expressed as the atomic ratio [Na + K] Al ) and the mineralogy. Decreasing agpaitic coefficient values are paralleled by a similar reduction of the zirconium concentration in the amphibole-granites → biotite-granites trend, while higher agpaitic coefficients and zirconium contents are associated with the amphibole-granites → riebeckite-granites trend.

K/Rb ratios have been determined in about 70 granites from Northern Nigeria. It is shown that late stage rocks such as albite-riebeckite-granites have ratios below 30 while early-stage rocks such as Ca-amphibole-granites can have ratios up to 330; biotite-granites have intermediate ratios. In the Liruei complex the ratio decreases progressively with time of emplacement but in the Amo complex the ratio varies irregularly.

The proteins in blood were all first expressed as mRNAs from genes within cells. There are databases of human proteins that are known to be expressed as mRNA in human cells and tissues. Proteins identified from human blood by the correlation of mass spectra that fail to match human mRNA expression products may not be correct. We compared the proteins identified in human blood by mass spectrometry by 10 different groups by correlation to human and nonhuman nucleic acid sequences. We determined whether the peptides or proteins identified by the different groups mapped to the human known proteins of the Reference Sequence (RefSeq) database. We used Structured Query Language data base searches of the peptide sequences correlated to tandem mass spectrometry spectra and basic local alignment search tool analysis of the identified full length proteins to control for correlation to the wrong peptide sequence or the existence of the same or very similar peptide sequence shared by more than one protein. Mass spectra were correlated against large protein data bases that contain many sequences that may not be expressed in human beings yet the search returned a very high percentage of peptides or proteins that are known to be found in humans. Only about 5% of proteins mapped to hypothetical sequences, which is in agreement with the reported false-positive rate of searching algorithms conditions. The results were highly enriched in secreted and soluble proteins and diminished in insoluble or membrane proteins. Most of the proteins identified were relatively short and showed a similar size distribution compared to the RefSeq database. At least three groups agree on a nonredundant set of 1671 types of proteins and a nonredundant set of 3151 proteins were identified by at least three peptides.

OVER 40 individual granitoid ring complexes exhibiting similar petrological and geochemical variations have been recognised in Nigeria1. They range in size from 1,500 km2 to < 2 km2. The ring complexes form part of a more extensive chain along the ninth meridian, extending from the north of the Air Massif through southern Niger and northern Nigeria to the northwestern margin of the Benue Trough in Nigeria (Fig. 1). In general the suite of Nigerian complexes are concentrated in a 200-km wide north-south zone and centred around the Jos Plateau. We have previously2 investigated the group of ring complexes forming the central zone of anorogenic magmatism in Nigeria, and found a southerly decreasing age trend from early Jurassic to mid-Jurassic times. We give here further evidence for this trend, and point out that its recognition may be useful in ascertaining the drifting motion of the African continent.