Trends of thought concerning meteorological research

Summary Certain problems of synoptic meteorology relating to the nature of the large quasi-stationary cyclonic and anticyclonic centers aloft are examined from the standpoint of an hypothesis which seeks to connect their maintenance with that of the smaller transient disturbances. The suggested link between these two scales of eddies is in many ways similar to that operating in the general circulaton in order to account for the sustained existence of the circumpolar mean zonal motions, according to the more modern concepts. Newer views concerning the dynamcis of large convective processes, and the essential nonlinearity of the laws governing motions in the atmosphere, figure importantly in the arguments advanced.

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Zusammenfassung Gewisse Probleme der synotischen Meteorologie im Zusammenhang mit der Natur von grossen halb-stationären zyklonischen und antizyklonischen Zentren in der höheren Atmosphäre werden von einem hypothetischen Standpunkt aus untersucht; und es wird versucht, deren Bestehen in Zusammenhang zu bringen mit dem Vorhandensein von kleineren, vorübergehenden Störungen. Der vorgeschlagene Zusammenhang zwischen diesen beiden Arten von Wirbel-Systemen ähnelt in vielen Beziehungen der allgemeinen Zirkulation, die verantwortlich ist für das fortwährende Bestehen der zirkumpolaren durchschnittlichen zonalen Strömungen, wie sie zufolge modernerer Auffassungen erklärt werden. Neuere Standpunkte, die die Dynamik von grossen konvektiven Vorgängen in der Atmosphäre und die nicht-linearen Gesetze im Hinblick auf die atmosphärischen Strömungs-Gesetze betreffen, werden hauptsächlich in der folgenden Abhandlung untersucht.

     

On a proposed plutonic porphyry gold deposit model

A plutonic porphyry gold deposit model is proposed that is imilar to the plutonic porphyry copper deposit model. However, unlike the plutonic porphyry copper deposit model, the proposed model is deficient in copper and contains less than 1 percent total sulfides. In the proposed model, gold is accompanied by scheelite, molybdenite, arsenopyrite, a variety of bismuth sulfides, tellurides, and native bismuth. The host rock varies from granite to granodiorite stock. Most of the ore is in the pluton. Deposits cited as examples of the proposed model are the Mokrsko deposit in Czechoslovakia, the Fort Knox deposit in the United States, and the Dublin Gulch deposit in Canada. In each of these deposits, pervasive potassic or phyllic alteration zones accompany the gold ore, which is disseminated in quartz-rich stockworks, veinlet swarms, and veins. Tonnages of gold-bearing material are large, but grades are low in the cited deposits. The proposed model is distinct from other gold deposit models because of the low Cu to Au ratio and the association of Au, Bi, W, and Mo.     

An empirical sapphirine-spinel Mg---Fe exchange thermometer and its application to high grade xenoliths in the Popes Harbour dyke, Nova Scotia, Canada

Spinel-sapphirine-corundum-rutile parageneses in metapelitic xenoliths from the lamprophyric Popes Harbour dyke are enclosed by feldspathic (±rare quartz) haloes that embay aluminosilicates and biotite. These feldspathic haloes contain plagioclase (An_20–40) and/or an alkali or ternary (hypersolvus) feldspar, and show a variety of igneous and devitrification textures, suggesting an anatectic origin. The spinel-bearing parageneses are interpreted as the refractory residue formed by the incongruent melting of biotite, aluminosilicates and associated phases.

Equilibration temperatures of these assemblages are estimated from an empirical sapphirine-spinel Mg---Fe exchange thermometer derived from literature data on both silica-saturated and undersaturated sapphirine granulites. Linear regression (R=0.81) of the calibrant data yields the expression T(°C) = [800 + (228^*InKd)] − 273 where

Kd=(X^sp_Fe/X^sp_Mg)/(X^sa_Fe/X^sa_Mg)

Precision is estimated at ± 100°C, but will likely be less for highly oxidized sapphirine granulites owing to (1) errors in the stoichiometric estimation of X_Fe³⁺ from microprobe data and (2) the formation of magnetite at the expense of spinel or sapphirine, leading to an increase in X_Mg in either or both phases during cooling. Application of this expression to the reduced (graphite-bearing) Popes Harbour xenoliths yields T of 725–795°C. Anatexis is attributed to thermal metamorphism by the lamprophyric magma prior to and/or during entrainment of xenolith material in the dyke. Higher-T assemblages were quenched before the xenoliths attained thermal equilibrium with the magma, consequently prograde reaction textures and compositional zoning patterns are preserved.     

Hydromorphic dispersion of Cu and Mo over mineralized granodiorite in a high rainfall peaty area in Ireland: geochemical interpretation and case study

Dispersion of Cu and Mo in mainly ombrotrophic-type peat and till on mineralized Galway Granodiorite, Ireland, is controlled by high rainfall (leaching of surface peat), organic content of till, limonite/bog iron, Eh and pH. Sampling surface blanket peat should be avoided in mineral exploration due to downward leaching. Copper accumulates more effectively than Mo in slightly reduced basal peat, organic-rich till, and organic-rich drain and stream beds. Molybdenum, being more mobile, occurs in a much broader range of organic-rich till, and limonite-stained till and lakeshore sediments. Hence, Mo is a useful pathfinder for Cu. Mobility of Cu and Mo is low due to complexation and/or adsorption, hence overburden anomalies make reasonable drill targets.     

Angular momentum transport in the solar nebula

Summary It is proposed that gravitational torques can furnish a mechanism for the radial outward transport of angular momentum in the solar nebula. For this effect to be present the disc of the nebula must have a spiral structure with trailing arms. A mathematical model is constructed with the main object of seeing whether purely advective inward eddy transports of angular momentum could offset the gravitational torques. It is found that for a protosun much more massive than the disc the eddy transport is small, allowing the gravitational effects of predominate. In such a case convergence of angular momentum is to be expected at the outer edge of the disc. The possibility exists that matter could be shed to large distances perhaps giving rise to the cloud of comets surrounding the solar system as proposed byJ. H. Oort.     

Legal control of pollution from North Sea petroleum development

Norwegian and British laws relevant to the control of marine pollution from North Sea petroleum development are briefly described. The emergence of law intended to reduce the probability of pollution from equipment failure or human error is noted, and suggestions are made to increase the effectiveness of this approach.     

Barium content of marine sediments near drilling sites: A potential pollutant indicator

Barite is commonly used as a weighting agent in oil- and gas-well drilling mixture; therefore, the distribution pattern of barium in marine sediments near drilling sites may provide an indicator of anthropogenic chemical contamination from these operations. Present average content of barium in benthic sediments from the Southern California Bight was determined to be 637 ppm, with a range from 43 to 1899 ppm, and that of the mainland and the channel island intertidal sediments averaged 879 and 388 ppm, respectively.