Aqueous Geochemistry of the Sand-and-Gravel Aquifer, Northwest Florida     

Brian G. Katz  Anne F. Choquette 《Ground water》1991,29(1):47-55

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Application of Marine Seismic Profiling to a Ground Water Contamination Study, Aberdeen Proving Ground, Maryland     

W. Brian Hughes 《Ground Water Monitoring & Remediation》1991,11(1):97-102

Continuous high-frequency marine seismic profiling was used to define the extent of geologic units in the offshore areas of J-Field, Aberdeen Proving Ground, Maryland, during March and April of 1988. J-Field is an area that was used by the U.S. Army for disposal of chemical warfare agents, munitions, and organic solvents from the 1950s through the 1970s. A major concern at this site is the subsurface migration of hazardous wastes into offshore areas and eventually into the Chesapeake Bay. A 150-foot (45.7 meter) deep paleochannel containing Pleistocene age fluvial and estuarine sediments was identified from boreholes constructed onshore. The paleochannel sediments consist of three lithic units. From bottom to top these units consist of gravel and sand, massive silty and sandy clay, and interbedded sand and clay. The seismic profiles were used to identify the extent of these units and map them in offshore areas. An accurate knowledge of the distribution of the geologic units in onshore and offshore areas is important to the investigation because the coarse-grained paleochannel sediments may provide a preferential flow path for contaminated ground water and the fine-grained sediments may impede the movement of contaminants into deeper aquifers.  相似文献   

Prediction of future short-term stream chemistry — a modelling approach     

Colin Neal  Alice Robson  Brian Reynolds  Alan Jenkins 《Journal of Hydrology》1992,130(1-4):87-103

The problem of predicting future short-term chemical behaviour in acidic and acid-sensitive streams is addressed. A relatively simple method is presented which combines a chemical technique for splitting the hydrograph into ground water and soil water components, based on the conservative component acid neutralization capacity, with the long-term hydrochemical model (MAGIC) in a ‘two-box’ mode. This method, coupled with a chemical speciation program (ALCHEMI), is used to assess short-term variations in stream chemistry with change in atmospheric deposition chemistry. The method is applied for a semi-natural moorland catchment in mid-Wales (Afon Gwy). For both hydrogen ion and inorganic aluminium, the modelled stream mixing relationships are non-linear, particularly at low hydrogen ion concentrations. The results also show that the relationship between hydrogen ion and inorganic aluminium concentrations varies with time in the stream. This result has important implications as it implies that aluminium concentrations will not recover, with reduced anthropogenic sulphur deposition, as rapidly as has previously been thought. Two methods, for use with critical load evaluation of ecological stress, are presented for describing the changes occurring: the hydrogen ion and inorganic aluminium concentration duration curve; the hydrogen ion and inorganic aluminium incident frequenty diagram.  相似文献   

Norfolk Broads controversy     

Brian Moss 《Marine pollution bulletin》1978,9(3):83-84

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Programmable Hand Calculator Programs for Pumping and Injection Wells: II — Constant Pumping (Injection) Rate, Single Fully Penetrating Well, Semiconfined Aquifer     

Don L. Warner  M. Gene Yow 《Ground water》1980,18(2):126-133

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Carbon-13 NMR spectra of macerals separated from individual coals     

Ronald J. Pugmire  Kurt W. Zilm  Warner R. Woolfenden  David M. Grant  Gary R. Dyrkacz  Carol A.A. Bloomquist  E.Phillip Horwitz 《Organic Geochemistry》1982,4(2):79-84

The density gradient centrifugation technique has recently been applied to the separation of macerals from whole coals. Sufficient quantities have been separated to permit examination of pure exinite, vitrinite and inertinite fractions by combined cross polarization and magic angle sample spinning (CP/MASS) carbon-13 NMR techniques. The similarities and differences observed in the maceral groups of two coals are discussed. Diversity in precursors or in differential chemical maturation or a combination of both of these factors can be used to account for subtle spectral differences in the two coals and macerals studied even though the gross spectral features are very similar for a given maceral type. The data show that CP/MASS is a technique that can address such interesting geochemical questions.  相似文献   

Selective elemental depletion during metamorphism of archaean granulites,scourie, NW Scotland     

Hugh R. Rollinson  Brian F. Windley 《Contributions to Mineralogy and Petrology》1980,72(3):257-263

The low abundances of large ion lithophile elements (LIL), K, Rb, U, Th, Cs, and high K/Rb ratio in rocks varying in composition from gabbro to granite in the Scourian complex, NW Scotland, are interpreted as due to depletion during granulite facies metamorphism. Depletion was controlled by the mineralogy of the rock, the composition of the associated fluid phase and its volume relative to the volume of the rock. K-feldspar granites and granodiorites were not depleted in K and only moderately in Rb, but tonalites and trondhjemites were strongly depleted in both K and Rb. Published mineral-fluid partition coefficients for LIL in aqueous systems indicate that between 0.075 and 2.0 rock volumes of fluid phase passed through the host rock in order to achieve the observed selective elemental depletion.  相似文献   

The age of the sub Mid-Jurassic tropical weathering profile of andoya,northern Norway,and the implications for the late palaeozoic palaeography in the North Atlantic region   总被引：1，自引：0，他引：1  

Brian A. Sturt  Arne Dalland  John L. Mitchell 《International Journal of Earth Sciences》1979,68(2):523-542

Results are given of a programme of K-Ar age determinations from an equatorial weathering profile beneath the Mid-Jurassic unconformitiy of Anøya, northern Norway. A model is presented where the original age of weathering is considered as Lower Carboniferous with partial resetting of ages during subsequent diagenesis. It is concluded that the Kaolinite of the weathering profile became a closed system of⁴⁰Ar diffusion in late Triassic times, and that a sufficient thickness of Mesozoic-Tertiary strata was never developed to occasion the resetting of the ages. The implication of the results is that a former thick cover of Upper Palaezoic age formerly existed in the region which was effectively removed by erosion in late Triassic — early Jurassic times. The results of the study are reviewed in a context of North Atlantic palaeogeographical evolution.

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Zusammenfassung Aus einem fossilen Bodenprofil unterhalb der mitteljurassischen Diskordanz in Nordnorwegen wurden K-Ar-Alter bestimmt, die auf eine Verwitterung während des Unterkarbons hinweisen. Während der folgenden Diagenese sind die Alter teilweise neu eingestellt worden. Dabei zeigt sich, daß der Kaolinite des ursprünglichen Bodenprofils erst ab Obertrias einem für Ar⁴⁰-Diffusion geschlossenen System angehört. Es folgt weiter, daß während des Mesozoikums und Tertiärs keine größere Sedimentbedeckung mehr über diesen Profilen möglich war, wohingegen eine erhebliche Mächtigkeit von jungpaläozoischen Sedimenten ehedem vorlag, die während der Obertrias abgetragen wurde. Diese Beobachtungen können mit der paläogeographischen Entwicklung des Nord-Atlantik in Zusammenhang gebracht werden.

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Résumé On a déterminé les âges K-Ar, donnés par un sol d'alteration formé pendant le Carbonifère inférieur et sous-jacent à la discordance du jurassique moyen, au nord de la Norvège. Les âges ont été en partie de nouveau déterminés, lors des diagénèses suivantes. Il en ressort que la Kaolinite du profil du sol originel n'appartient à un système fermé de diffusion Ar⁴⁰ qu'à partir du Trias supérieur. Il s'ensuit qu'un recouvrement sédimentaire épais n'a pu se déposer sur ce profil au cours du Secondaire et du Tertiaire, tandis qu'une épaisseur considérable de sédiments du Paléozoique supérieur existait, enlevès ensuite par érosion au Trias supérieur. Ces observations peuvent être mises en rapport avec le développement paléogéographique de l'Atlantique-Nord.

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Monitoring the biological effects of North Sea platforms     

Brian Dicks 《Marine pollution bulletin》1982,13(7):221-227

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Evidence of tidal processes from the lower part of the Witwatersrand Supergroup,South Africa     

Kenneth A. Eriksson  Brian R. Turner  Richard G. Vos 《Sedimentary Geology》1981,29(4):309-325

A 1600-m succession of quartz arenites and associated shaley deposits comprising the Hospital Hill Subgroup at the base of the Witwatersrand Supergroup is considered to have been deposited largely under the influence of tidal processes. Facies analysis indicates that deposition occurred in the following environments: (1) marine shalf; (2) shallow subtidal to intertidal; (3) intertidal flat; and (4) tidal inlet. The presence of strong tidal currents implies that the Witwatersrand Basin was open to an ocean basin, at least during the early stages of its evolution. Palaeocurrent trends and isopach data suggest that this probably lay to the southwest, an area now occupied by the high grade Natal—Namaqua metamorphic belt. The contrast between the supermature quartz arenites of the Hospital Hill Subgroup and the overlying gold-bearing immature subgreywackes, feldspathic quartzites and conglomerates of fluvial origin is believed to be a function of tidal reworking of sediments.  相似文献