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Robotham, H., G.C. Lalor, A. Mattis, R. Rattray  and C. Thompson.  1987. Trace Elements In Jamaican Soils Part I: The Parishes of Clarendon, St. Catherine, Portland and St. Elizabeth. Journal of Radioanalytical and Nuclear Chemistry,116(1), 27-34.

The results of the analysis of approximately 100 soil samples for Na, Mg, Al, K, Ca, Sc, Ti, V, Cr, Mn, Fe, Co, As, Sb, Ba, La, Sm, Eu, Dy, Lu, Hf, Th, and U by neutron activation analysis, in three soil horizons from four of the main agricultural parishes of Jamaica are presented. While there is some regional variation in the abundances, there are no statistically significant distribution of abundances across the horizons. The results for a few selected elements are compared with abundances in other countries.

Bertolaccini, M., G. Padovini, D.V. Camin, P.F. Manfredi, J.A. Preston and L.A. Rehn.  1988. Perspectives in the Design of Transformerless, Low-Noise Front End Electronics for Large Capacitance Detectors and Calorimeters in Elementary Particle Physics. Journal of Nuclear Instruments and Methods in Physics Research, A264, 399-406.

The achievement of adequate signal-to-noise ratios in the measurement of the energy released by ionizing particles in detectors of large capacitance such as, for instance, calorimeter cells, frequently relies upon transformer coupling between detector and preamplifier. Such a solution, however, may not be feasible if the detector is located in a strong magnetic field. This paper discusses the possibilities opened up by a recently developed field effect transistor of large gate area, whose design has been tailored to the applications in front-end preamplifiers for calorimeters and other large capacitance detectors of frequent use in elementary particle physics.

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Simpson, P.R., G.C. Lalor, H. Robotham, J. Hurdley, A.E. Milodowski, J.A. Plant and T.K. Smith.  1988.  New evidence of epithermal gold potential in andesitic volcanics of the Central Inlier, Jamaica. Journal of Transactions of the Institution of Mining and Metallurgy (Sect.B: Applied Earth Sci.), B88-91.

Detrital native gold of high fineness is reported in drainage samples from the Mountain River at Cudjoe Hill on the southeast margin of the Central Inlier, St. Catherine Parish, Jamaica (Fig1). The gold is associated with volcano-sedimentary sequences of andesitic affinities and with anomalous geochemical haloes for As and Ag, which are indicative of epithermal gold mineralization. The volcanic pile has been locally intruded by Cretaceous granodiorite at Ginger Ridge, 2.5 km southwest of Juan de Bolas mountain (Fig1).

The Caribbean plate is a favourable area for gold exploration and, by analogy with the prolific western Pacific plate margin, has potential for epithermal deposits related to volcanic hot springs at crustal plate boundaries. Jamaica has no record of gold mining, though Sawkins recognized the gold potential of mineralization in the Stamford Hill, Charing Cross and Gold Mine localities in northeast Clarendon to the west of the present study area, which he classified as gold ore.

Lalor, G.C., J.M. Miller, H. Robotham and P.R. Simpson.  1989. Gamma radiometric survey of Jamaica. Journal of Transactions of the Institution of Mining and Metallurgy, 98.

The results of a total gamma radiometric survey of Jamaica, carried out with car-borne instrumentation, are presented and the data compared with the contents of potassium, thorium and uranium in rocks and in surface (soil, stream-sediment, pan concentrate and water) samples obtained at six sites selected to be representative of the principal rock types and surface environments of Jamaica.The work formed part of an orientation study for a regional geochemical survey of the CARICOM countries of the Caribbean. The initial results indicate that enhanced gamma activity is correlated with enrichment in uranium and thorium, but not potassium, in terra rossa soils and/or bauxite deposits in limestone. Elsewhere, gamma levels are increased on the Above Rocks Cretaceous basement Inlier, where they correlate generally with the presence of volcanogenic sediments and a granodiorite intrusion. The lowest radioactivity was recorded in the vicinity of ultrabasic rocks in the Blue Mountains Inlier.

Bajue, S., G. Dasgupta, G.C. Lalor, H. Robotham. 1989.  Acid Dissociation and nickel-complex formation constants of some nitrosonapholsulphanoate ligands. Polyhedron, 8(4), 473-477.

The acid dissociation constants of several 1-nitroso- and 2-nitroso-naphthosilphonate ligands, and the formation constants of their Ni²⁺ mono-complexes are reported. The measurements were performed in the temperature range 20.0 - 30.0^oC and ionic strength 0.1 mol dm^-3.

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Lalor, G.C., R. Rattray, H. Robotham and C. Thompson.  1990. The Slowpoke-2 Nuclear Reactor at the University of the West Indies. Jamaica Journal of Science and Technology, 1(1), 65-77.

The University of the West Indies (UWI) operates a small nuclear reactor, the SLOWPOKE-2. This reactor is designed for isotope manufacture and neutron activation analysis. The maximum operating flux is a useful 1 x 10¹² neutrons cm^-2s^-1. The reactor is designed to be inherently safe and even the worst credible accident should present no threat to the environment. The reactor is being used mainly for neutron activation analysis. The major programme to which the reactor is applied is to develop a computer readable regional database which will be of value in agriculture, animal and human health, land use planning, and the assessment of natural resources. This paper describes the physical characteristics of the reactor, its safety philosophy, and its application to neutron activation analysis. The assessment of the quality of the results obtained as well as the automation of the system are also presented and discussed.

Heffes, T.P.,  P. Coates-Beckford and H. Robotham. 1991.  Effects of Meloidogyne incognita on growth and nutrient content of Amaranthus virdis and cultivars of Hibiscus sabdariffa. Nematropica, 21(1).

Pots with seedlings of callaloo (Amaranthus virdis) and the "Red" and "White" cultivars of sorrel (Hibiscus sabdariffa) were inoculated with 0, 100, 1,000 and 10,000 eggs of Meloidogyne incognita race 1 and the plants were grown for 6 weeks in a greenhouse. Nematode reproduction was good on Red sorrel, poor on callaloo, and was inhibited by White sorrel. Dry weights of infested callaloo roots were greater than weights of noninfested roots. Shoot heights, leaf areas, and dry shoot and root weights of infested plants of both sorrel cultivars were less than those of noninfested plants. The concentrations of the nutrients varied with the host, plant organ and initial nematode density. The shoot/root ratios of the elements were similar at all inoculum levels (Pi) except those of callaloo roots at Pi = 10 000, which had significantly lower and higher ratios of sodium and manganese, respectively, than those of noninfested plants.

Robotham, H., G.C. Lalor, R. Rattray, C. Thompson, J. Thomas, J. Hurdley, J.A. Plant and P.R. Simpson. 1991.  Orientation studies for regional geochemical surveys in Jamaica.  Journal of The Geological Society of Jamaica, 19(1), 17-26.

Aspects of an orientation study carried out to determine the optimum methods of sampling and analysis for a regional geochemical survey of Jamaica are described. The survey is intended to provide a multi-element geochemical database suitable for agriculture, land-use planning and environmental studies as well as to identify areas with potential for the discovery of economic mineral deposits. Detailed studies of element pathways have been carried out based on the analyses of rock, soil, stream sediment and water samples at six sites selected to represent the main rock types and environments of the island. This paper describes those aspects of the study which are concerned with evaluating, with particular reference to the selection of appropriate subsampling methods. Size fraction analysis of soils and stream sediments from the orientation sites shows that soils contain a higher proportion of fine fraction material than stream sediments, with the percentage of the –100 mesh fraction, for example, ranging from 24.1 to 85 per cent with a median of 59.2 per cent, compared to a range of 5.5 to 65.5 per cent with a median of 12.6 per cent in stream sediments. The fine fraction of stream sediment is particularly sparse at sites where streams drain.

Cretaceous basement exposed in the higher mountainous areas of the Central and Blue Mountain inliers. The relationship between the levels of chemical elements and particle size is discussed with particular reference to Ba, Cr and As, which show contrasting types of behaviour in the surface environment. Soils are shown to provide better differentiation between the different lithologies sampled and also to provide improved and more consistent peak-to-background ratios than stream sediments over occurrences of metalliferous mineralization. These factors, together with the poor surface drainage developed over the greater part of the island, which is covered by limestone, suggest that multipurpose regional geochemical mapping in Jamaica and probably elsewhere in the Caribbean should be based on soil sampling, supplemented as necessary by other sample types.

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Simpson, P.R., J. Hurdley, G.C. Lalor, J.A. Plant and H. Robotham. 1991.  Orientation Studies in Jamaica for Multi-purpose Geochemical Mapping of Caribbean Region. Journal of Transactions of the Institution of Mining and Metallurgy  Vol. 100:47-158.

 The results of orientation studies for a regional geochemical survey of Jamaica and the CARICOM countries of the Caribbean region are described. The survey is designed to provide systematic geochemical information for a wide variety of applications and, especially, to form a basis for agricultural development in the region. The programme is modelled on the Geochemical Survey Programme (GSP) being carried out in Great Britain by the British Geological Survey (BGS), which is preparing, in digital form, a highresolution geochemical database suitable for a range of environmental and economic investigations.

The application of rock, soil, stream-sediment and water sampling to define the regional geochemistry of Jamaica is described with particular reference to sources of error and the                     modification of trace-element patterns in different surface environments. Contrasts on the island are marked, with approximately 70% of the land area underlain by an Eocene to mid-Miocene platform-limestone cover with bauxite deposits. The remainder, which mainly comprises a Cretaceous basement complex, outcrops as a series of inliers that are exposed in a central, east-west-trending chain of mountains.

Studies of sampling and sub-sample preparation methods indicate that soil samples of particle size<=150 µm (100 BSI mesh) provide the optimum sampling medium for a regional geochemical survey of Jamaica. They contain a higher proportion of fine- fraction material than stream sediments, particularly in the mountainous areas of the Central and Blue Mountains Inliers; they also provide a better and more consistent means of differentiating rock types and occurrences of metalliferous mineralization while, unlike stream sediments, showing minimal variation of element concentrations in relation to particle size. Soil samples thus provide a robust sample type, with trace-element levels that are unaffected by variations in the proportions of different size fractions arising as a result of operator error, geomorphology or temporal climatic changes. Studies of the dispersion of elements in six catchment basins that were selected to represent the main rock types and environments of the island suggest that a sampling interval of one soil sample per 5 km² is adequate to define anomalous metal concentrations and that regional variation can be represented on the same interval. The primary geochemistries of most rock types and of occurrences of metalliferous mineralization in Jamaica have been intensely altered as a result of surface processes. Intense leaching of elements of low ionic potential (Ca, Mg, K, Rb, Ba and Sr) and U has occurred (although U is frequently resorbed by iron oxides in bauxite and terra rossa soils). In contrast, other elements, such as Mo, As and, to a lesser extent, Cr, Ni, Co, Fe and Mn, are strongly enriched in soils (and stream sediments) relative to bedrock.  Enrichment is attributed to the formation of secondary ferric/ manganic (Mo, As, Cr, Ni and Co) and phosphatic (As) phases. Only the content of high field strength elements, such as Zr, Hf, Th and the rare-earth elements, can be used to deduce bedrock chemistry. A more complex dispersion model is thus required for Jamaica than those developed previously for tropically weathered terraines, such as Australia- where landscapes are frequently more than 10 m.y. old.

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