Some limitations in the geostatistical evaluation of ore deposits     

G. M. Philip  D. F. Watson 《Geotechnical and Geological Engineering》1985,3(2):155-159

Conclusions The foregoing discussion indicates that geostatistical estimation of ore deposits is not local; it is not objective; it is not sensitive to local data trends; and it is not unrestrained by the range of data values.Kriging, as an interpolation method, is a variant of IDW least squares linear fit. As such, it suffers from the limitations of all IDW linear interpolation methods that employ only data values.The estimation variance, currently used to calculate the confidence limits of values for individual mining blocks, is hypothetical and globally derived. It is more closely related to sampling density than to local variation in the data set.Geostatistical methods, of course, have a real place in ore deposit assessment, e.g. global, comparative evaluation to assist decisions on development and investment. What is questioned here is the validity of employing a global method to assess detail (mining blocks) within an ore deposit.  相似文献   

Henry's law behavior in simple systems and in magmas: Criteria for discerning concentration-dependent partition coefficients in nature     

E.Bruce Watson 《Geochimica et cosmochimica acta》1985,49(4):917-923

Although numerous questions still surround the topic of Henry's law (HL) as it applies to trace element partitioning, there now exist sufficient experimental data to make some generalizations regarding HL behavior in minerals. The most important of these is that the commonly-observed failure of HL at low concentration occurs at distinctly different levels even for chemically-similar elements in a single mineral. This observation in turn provides a basis for discerning effects of HL failure in natural systems: through examination of element ratios in minerals and rocks, it is possible, in principle, to distinguish HL effects from changes in partition coefficients due to variations in other magmatic parameters such as temperature and the compositions of phases. Initial applications of this approach to plagioclase/ liquid partitioning of REE and to the general behavior of $\text{Zr}\text{Hf}$ and $\text{Ba}\text{Rb}$ during basalt production suggest that HL usually does hold in nature.  相似文献   

Element associations and distributions through a Lower Palaeozoic graptolitic shale sequence in the Southern Uplands of Scotland     

W.E. Stephens  S.W. Watson  P.R. Philip  J.A. Weir 《Chemical Geology》1975,16(4):269-294

The Lower Palaeozoic graptolitic sequence in the Southern Uplands of Scotland (Moffat Shales) is a highly condensed succession of marine shales, with much of the Ordovician and Early Silurian being represented by about 100 m of shales, mudstones and cherts. A total of 133 samples were collected from five main inliers and zoned by their graptolitic assemblages. These were analysed for the elements Si and Al (94 samples), Mg (80 samples), Ti, Fe, Mn, Ca, Na, and K (33 samples), and Cu, Pb, Zn, Rb, Sr, Y and Zr (133 samples). X-ray diffraction studies reveal the presence of quartz, illite, chlorite, carbonate and pyrite and these can be related to element associations brought out by correlation and multivariate statistical techniques. These studies reveal a systematic change up the succession based on an increasing contribution of clay to these sediments. Interpretation of the principal components indicates the main control of sedimentation to be physiographic, with physico-chemical conditions and decay of organic matter also being important.  相似文献   

Probable origin of the Livingston Fault Zone     

Watson H. Monroe 《Environmental Geology》1991,18(2):83-84

Most faulting in the Coastal Plain is high angle and generally normal, but the faults in the Livingston Fault Zone are all medium-angle reverse, forming a series of parallel horsts and grabens. Parallel to the fault zone are a number of phenomena all leading to the conclusion that the faults result from the solution of a late Cretaceous salt anticline by fresh groundwater, which then migrated up to the Eutaw and perhaps Tuscaloosa aquifers, causing an anomalous elongated area of highly saline water. The origin of the Livingston Fault Zone and the association of salt water in underlying aquifers is of particular importance at this time in relation to environmental concerns associated with hazardous waste management in the area.  相似文献   

Inclusion/host relations involving accessory minerals in high-grade metamorphic and anatectic rocks   总被引：1，自引：0，他引：1  

E. Bruce Watson  Edward P. Vicenzi  Robert P. Rapp 《Contributions to Mineralogy and Petrology》1989,101(2):220-231

In general, accessory minerals are expected to participate in partial fusion of their host rocks to a degree determined simply by their solubilities in the melt. The possibility must be recognized, however, that a given accessory grain may be physically isolated from the melt by inclusion within a residual major mineral. Because of the importance of accessory minerals to crustal-rock trace element and isotope geochemistry, and because of their common existence as inclusions in major phases, we undertook an evaluation of the factors that affect inclusion formation during ultrametamorphism. Three approaches are taken: 1) a review of interfacial energy considerations is used to show that the free energy of the system is lowered by location of accessory minerals at major-phase grain perimeters, and that the magnitude of this effect is proportional to the square of the accessory grain radius; 2) annealing and partial melting experiments (1000° C, 10 and 15 kbar) on rock analogs are described, and the results are shown to confirm the predicted tendency of accessory minerals to occupy grain boundaries; and 3) the results of a study of accessory phase (rutile and zircon) distribution in a migmatite from the Tibetan slab are reported, again in confirmation of the prediction that accessories tend to be situated at majorphase grain perimeters. The latter two aspects of the study reveal that, although included accessory grains are common, their generally small size results in only a minor contribution to the bulk-rock budget of accessory mineral components: Most of the mass of these components is contained within populations of generally larger accessory grains located at major-phase grain boundaries. Accordingly, the assumption that accessory minerals are involved in crustal melting is generally valid.  相似文献   

Book review     

Richard G. Craig  Geoffrey S. Watson 《Mathematical Geosciences》1989,21(4):483-485

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The Balloon Intercomparison Campaigns an introduction and overview     

R. T. Watson  H. K. Roscoe  P. T. Woods 《Journal of Atmospheric Chemistry》1990,10(2):99-110

The Balloon Intercomparison Campaigns of 1982 and 1983 compared balloon-borne sensors of HCl, HNO3, NO2, NO and O3, and measured many other stratospheric constituents. Most sensors were remote rather than in-situ. In the 1982 campaign, three large gondolas were successfully launched from Palestine, Texas on the same day; in the 1983 campaign, four gondolas were launched within 3 days. Accompanying papers describe the results of these successful intercomparisons.  相似文献   

Determinants of species susceptibility to oxidative stress: A comparison of channel catfish and brown bullhead     

Richard T. Di Giulio  Jeff V. Behar  David B. Carlson  Bruce M. Hasspieler  David E. Watson 《Marine environmental research》1995,39(1-4)

Xenobiotic-mediated productions of reactive oxygen species, via enzymemediated redox cycling, have been implicated in a variety of toxicological phenomena including lipid peroxidation, enzyme inactivation and oxidative DNA damage leading to cancer. A comparison was undertaken of two benthic freshwater fish species that appear to differ markedly in their susceptibility to chemical carcinogenesis—the channel catfish (Ictalurus punctatus) and the more cancer-prone brown bullhead (Ameriurus nebulosus)-in terms of basic biochemical characteristics related to oxidative stress. This has included analysis of microsomal redox cycling of model xenobiotics (e.g. menadione) as well as antioxidant and other detoxifying enzymes in hepatic tissue of the two species. In addition, endpoints of oxidative stress, such as altered glutathione status and oxidative DNA damage, were examined. These studies have revealed numerous qualitative and quantitative differences between the two species both in terms of basal enzyme activities and in species response to model prooxidants. For example, bullhead appear to possess a greater capacity for microsomal redox cycling of xenobiotics, but have glutathione-dependent defense systems less able to withstand oxidative challenge. These and other interspecific differences have allowed for an improved understanding of the basic mechanisms which may underly species susceptibility to oxidative stress and critical manifestations such as cancer.  相似文献   

COSMOSOMAS observations of the cosmic microwave background and Galactic foregrounds at 11 GHz: evidence for anomalous microwave emission at high Galactic latitude     

S. R. Hildebrandt  R. Rebolo  J. A. Rubiño-Martín  R. A. Watson  C. M. Gutiérrez  R. J. Hoyland  E. S. Battistelli † 《Monthly notices of the Royal Astronomical Society》2007,382(2):594-608

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The optimum distance at which to determine the size of a giant air shower     

D. Newton  J. Knapp  A.A. Watson 《Astroparticle Physics》2007,26(6):414-419

To determine the size of an extensive air shower it is not necessary to have knowledge of the function that describes the fall-off of signal size from the shower core (the lateral distribution function). In this paper an analysis with a simple Monte Carlo model is used to show that an optimum ground parameter can be identified for each individual shower. At this optimal core distance, r_opt, the fluctuations in the expected signal, S(r_opt), due to a lack of knowledge of the lateral distribution function are minimised. Furthermore it is shown that the optimum ground parameter is determined primarily by the array geometry, with little dependence on the energy or zenith angle of the shower or choice of lateral distribution function. For an array such as the Pierre Auger Southern Observatory, with detectors separated by 1500 m in a triangular configuration, the optimum distance at which to measure this characteristic signal is close to 1000 m.  相似文献