Mercury in tissues of mussel off southern California     

Robert P. Eganhouse  David R. Young 《Marine pollution bulletin》1976,7(8):145-147

Total mercury content has been determined in three tissues of the intertidal mussel Mytilus californianus collected at locations along the southern California coast and at island control stations. The apparent influence of certain harbours and municipal wastewater outfalls was reflected by the relatively higher levels of mercury in all tissues of mussels from these areas. In general, the concentrations reported here are lower than those in mussels on west European coasts.  相似文献   

Distribution and source of tar on the Pacific Ocean     

C.S Wong  David R Green  Walter J Cretney 《Marine pollution bulletin》1976,7(6):102-106

Petroleum residues, or tar lumps, are concentrated in the northwestern portion of the Pacific Ocean, particularly in the Kuroshio current system. The source of the tar appears to be tank washings from tankers on the very large Middle East to Japan route. Tar pollutants apparently are discharged by tankers south of Japan, become entrained in the Kuroshio current, and create a plume of contamination which extends downstream for 7000 km across the Pacific.  相似文献   

International liability for weather modification     

Edith Brown Weiss 《Climatic change》1978,1(3):267-290

Can a State be held liable to another State or to citizens of another State for damage caused by (a) the State's own weather modification activities; (b) weather modification activities conducted by a nongovernmental party within its borders, or (c) weather modification activities conducted by persons within its control but outside its borders? What measures can be taken by a State to minimize its liability for weather modification activities? This article tries to answer these questions. It focuses on liability under international law, and emphasizes issues related to cloud-seeding to affect precipitation and to hurricane modification.  相似文献   

On eddy convection velocity in the atmospheric boundary layer     

David P. Chock 《Boundary-Layer Meteorology》1978,14(3):397-402

Lumley's model is extended to predict the effect of convection velocity fluctuations on eddy convection velocity for the high-frequency region of the longitudinal, transverse and scalar phase spectra in the atmospheric boundary layer. The resulting model predicts that the eddy convection velocity will be higher than the mean wind speed. The increase over the mean wind speed is largest for the longitudinal spectrum.  相似文献   

Nappe displacement in the Scandinavian Caledonides   总被引：1，自引：0，他引：1  

David G. Gee 《Tectonophysics》1978,47(3-4)

Large areas of the Scandinavian Caledonides are eroded to the level of the basement/cover contact. Relationships between the Precambrian crystalline basement (largely Svecofennian-Dalslandian, 1800-1000 m.y.) and cover sequences are exposed both in transverse profiles through the mountain belt and along the belt in the various windows. These relationships provide an unique opportunity for studying the basement configuration, character of basement involvement and general nappe geometry. Major allochthonous units of the central part of the Scandinavian Caledonides — the Offerdal, Särv and Seve-Köli Nappe Complex — have been shown to wedge out westwards, having been displaced eastwards from environments along and west of the present Norwegian coast. Recent investigations have shown that these units (the Offerdal, Särv and Seve) reappear in western Norway as major pinch-and-swell structures, the lenses reaching thicknesses in the order of 2 km and with long axes of several tens of kilometres. Within the western parts of the Swedish Caledonides the thicker parts of the lenses approximately coincide with the axes of the late synforms which fold basement and cover together. Further west, in Norway, the tensing appears to be unrelated to the geometry of these major folds.This evidence increases estimates of nappe displacement distance (now thought to be in the order of at least 1000 km). At the same time it emphasizes that translation may account for only about half of this amount, the rest being achieved by stretching of the nappes. Apparently, a nappe sequence built up in the west which subsequently collapsed, leading to continued displacement eastwards on to the Baltoscandian Platform. Whereas basement shortening is of the order of several tens to perhaps hundreds of kilometres in the western part of the central Scandes, it is of lesser importance from central Trøndelag eastwards, a distance of about two hundred kilometres, to the Caledonian Front.Biostratigraphic evidence from the late-orogenic intramontane basins, taken in relation to the youngest units involved in the nappes, requires nappe translation into western Norway to have occurred after the Llandoverian (Köli Supergroup) and prior to the (Ludlovian?) Downtonian (Hitra Formation) deposition in the intramontane basins. The nappes contain sequences derived from a variety of probable oceanic and continental margin environments, and this translation may greatly exceed the minimum estimate of five hundred kilometres. Further displacement eastwards occurred during uplift of seaboard Norway and accompanied sedimentation both in the intra- and extramontane basins. The latter were not finally influenced by the décollement tectonics until after the Early Devonian.This evidence suggests that a compressive regime dominated the early phases of orogenesis during basement shortening, build up of the nappe pile and translation of these denser units on to the western margin of the Baltoscandian Platform. This compression subsequently gave way to a gravity regime, collapse and stretching of the nappes dominating the late phases of displacement on to the Baltoscandian Platform.  相似文献   

Submergence avoidance behavior in the periwinkleLittorina irrorata is not due to threat of drowning     

David F. Bleil  Mary E. Gunn 《Estuaries and Coasts》1978,1(4):267-267

An attempt to establish an LD₅₀ for submergence onLittorina irrorata casts strong doubt on the hypothesis that submergence avoidance behavior is due to the threat of drowning. Predator avoidance is offered as a more plausable hypothesis. Respiration rates of 2.73×10^?3 ml O₂/g body wt./min. for submerged snails and 2.70×10^?2 ml O₂/g body wt./min. for controls were determined.  相似文献   

A post-Transvaal age for the Marydale Formation,Kheis Group,Southern Africa     

David H. Cornell 《Earth and Planetary Science Letters》1977,37(1):117-123

The metabasic Marydale Formation of the Kheis Group occupies a zone of contact between the Sanama and Kaapvaal structural provinces of South Africa. Stratigraphic relationships between the two provinces are not well understood. Whilst the well-known Kaapvaal basement and supracrustal succession yield radiometric ages older than 1900 m.y., Sanama Province ages reflect a Kibaran(1200 ± 200m.y.) tectogenetic cycle. The age of the Marydale, stratigraphically the oldest Sanama formation, has been variously estimated at2500m.y., about 2000 m.y., or Kibaran, based on controversial field interpretations or on available radiometric data.Rb-Sr data are presented for Marydale samples from a nappe-like body which, having been thrust over the Kaapvaal basement, was shielded from metamorphism. Two types of alteration are described and possible causes of isotopic homogenisation are discussed. It is concluded that an isochron age of 1899± 57m.y. (I = 0.7040 ± 0.0003) represents the age of extrusion of the Marydale volcanics.The stratigraphic controversy is thus resolved, Kheis Group formations being approximately coeval with the Matsap, the youngest formation of the Kaapvaal Precambrian succession. The implications of this and other recent work to theories of crustal evolution are considered. It is suggested that the continental crust of Sanama Province originated partly during the Eburnian(2000 ± 100m.y.) period of African orogeny and partly during the Kibaran tectogenetic cycle during which the province became cratonised and was added to the Southern African cratonic block.  相似文献   

Seismic reflections from Precambrian crust     

Scott B. Smithson  Peter N. Shive  Stanley K. Brown 《Earth and Planetary Science Letters》1977,37(2):333-338

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Composition and petrology of the Earth's mantle: A.E. Ringwood. McGraw-Hill Book Company Ltd., Maidenhead, 1975, 618 pp., 152 figs., 70 tables,UK £ 22.15     

G.Malcolm Brown 《Physics of the Earth and Planetary Interiors》1977,15(1):109-110

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Space geology — An introduction: Elbert A. King. John Wiley & Sons,Ltd., Chichester, 1976, 349 pp., 180 figs., 33 tables,glossary, UK £ 10.25, US $ 18.95     

G.Malcolm Brown 《Physics of the Earth and Planetary Interiors》1977,14(2):179-180

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