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251.
Xianrong Luo Baohong Hou Meilanna Wen Nanshi Zeng Keeling John Fidler Roger Fabris Adrian 《中国地球化学学报》2008,27(2):198-202
A version of the geoelectrochemical prospecting technique developed in China was demonstrated in China and Australia to test its suitability under both Chinese and Australian conditions. This paper briefly describes the mechanism and effectiveness of the technique applied to search of concealed mineralisation through regolith cover, based on both experimental and field tests. This paer deals with three main aspects of the method: a) how metallic ions are released from orebodies by electrochemical dissolution; b) how these ions migrate to the collector and are deposited as elements by electrochemical extraction in the presence of an electric field; and c) the effectiveness of the method illustrated by some case studies. 相似文献
252.
Groundwater catchment boundaries and their associated groundwater catchment areas are typically assumed to be fixed on a seasonal basis. We investigated whether this was true for a highly permeable carbonate aquifer in England, the Berkshire and Marlborough Downs Chalk aquifer, using both borehole hydrograph data and a physics‐based distributed regional groundwater model. Borehole hydrograph data time series were used to construct a monthly interpolated water table surface, from which was then derived a monthly groundwater catchment boundary. Results from field data showed that the mean annual variation in groundwater catchment area was about 20% of the mean groundwater catchment area, but interannual variation can be very large, with the largest estimated catchment size being approximately 80% greater than the smallest. The flow in the river was also dependent on the groundwater catchment area. Model results corroborated those based on field data. These findings have significant implications for issues such as definition of source protection zones, recharge estimates based on water balance calculations and integrated conceptual modelling of surface water and groundwater systems. Copyright © 2015 John Wiley & Sons, Ltd. 相似文献
253.
A pre-Ipswichian cold stage mammalian fauna from the Balderton Sand and Gravel,Lincolnshire, England
The Balderton Sand and Gravel has yielded one of very few mammalian faunas dated to the penultimate Cold Stage in Britain. The assemblage is dominated by mammoth and woolly rhinoceros, with subordinate horse, red deer, bison, straight-tusked elephant, musk ox, reindeer, wolf, lion, brown bear and cf. narrow-nosed rhinoceros. This fauna indicates cold stage conditions, probably including one or more interstadial episodes. The presence of straight-tusked elephant and cf. narrow-nosed rhinoceros supports its pre-Devensian age, and provides corroboration for the occurrence of these taxa in the British Wolstonian. An attempt is made to analyse the fossil collection by preservation type and adhering sediment: the occurrence of individual species appears to be largely uncorrelated with lithology. The Balderton assemblage corresponds well to other British mammal faunas assigned to a cold interval between the Hoxnian and Ipswichian Interglacials. 相似文献
254.
Adrian E. Scheidegger 《地学学报》1993,5(6):560-562
The orientation structures of lava flows and lava cracks in Hawaii (Big Island) have been analysed statistically. It is shown that the lava flows do not follow epigenetic random directions, but instead follow channels that have been endogenically predesigned. Similarly, the cracks in these flows have consistent directions at 45° to the edges of the lava flows. Thus, these cracks are not simply ‘cooling joints’ but features that correspond to the edge-crevasses in glacier-flow: they are shearing phenomena that occur in a similar fashion in any plastic-type flow. 相似文献
255.
Dipak Munshi Lung-Yih Chiang Peter Coles & Adrian L. Melott 《Monthly notices of the Royal Astronomical Society》1998,293(3):L68-L72
Using an ensemble of high-resolution 2D numerical simulations, we explore the scaling properties of cosmological density fluctuations in the non-linear regime. We study the scaling behaviour of the usual N -point volume-averaged correlations, but also examine the scaling of the entire probability density function (PDF) of the fluctuations. We focus on two important issues: (i) whether the scaling behaviour of 2D clustering is consistent with what one infers from radial collapse arguments; and (ii) whether there is any evidence from these high-resolution simulations that a regime of stable clustering is ever entered. We find that the answers are (i) yes and (ii) no. We further find that the behaviour of the highly non-linear regime in these simulations suggests the existence of a regime in which the correlation function is independent of the initial power spectrum. 相似文献
256.
257.
InformationsOther Future Meetings
2. International Symposium on Applications of geodesy to engineering 相似文献258.
Nitrogen loading to aquatic ecosystems from sewage is recognised worldwide as a growing problem. The use of nitrogen stable isotopes as a means of discerning sewage nitrogen in the environment has been used annually by the Ecosystem Health Monitoring Program in Moreton Bay (Australia) since 1997 when the technique was first developed. This ("sewage plume mapping") technique, which measures the delta(15)N isotopic signature of the red macroalga Catenella nipae after incubation in situ, has demonstrated a large reduction in the magnitude and spatial extent of sewage nitrogen within Moreton Bay over the past 5 years. This observed reduction coincides with considerable upgrades to the nitrogen removal efficacy at several sewage treatment plants within the region. This paper describes the observed changes and evaluates whether they can be attributed to the treatment upgrades. 相似文献
259.
Different from drinking water supplied by the municipal network or from other bottled waters, all of which undergo some kind of prior treatment in order to become potable, the natural mineral water is an ecologically pure product, that by virtue of its composition may induce beneficial health effects. According to the EC Directive 80/777, the main criteria used for defining the natural mineral water refer to its original purity and its adequate protection against any pollution hazard. In Romania, mineral water consumption is an old tradition. The geological setting and the existence of unpolluted areas favored the development of mineral water sources of an outstanding quality, many of which include also carbon dioxide in natural state. The present work presents the main sources of bottled mineral water in Romania, classified as a function of total mineral content, ionic composition and carbon dioxide content. There are also forwarded forecasts concerning the medium term evolution of the structure of the bottled mineral water market in Romania. 相似文献
260.
Peter?M.?EldridgeEmail author James?E.?Kaldy Adrian?B.?Burd 《Estuaries and Coasts》2004,27(6):923-937
Our modeling objective was to better define the relationship between subtropical seagrass and potential water column and sediment
stressors (light, organic and particle sedimentation, sediment nutrients, and the porewater sulfide system). The model was
developed and optimized for sediments inThalassia testudinum seagrass beds of Lower Laguna Madre, Texas, U.S., and is composed of a plant submodel and a sediment diagenetic submodel.
Simulations were developed for a natural stressor (harmful algal bloom,Aureoumbra lagunensis) and an anthropogenic, stressor (dredging event). The observed harmful algal bloom (HAB) was of limited duration and the
simulations of that bloom showed no effect of the algal bloom on biomass trends but did suggest that sediment sulfides could
inhibit growth if the bloom duration and intensity were greater. To examine this hypothesis we ran a simulation using data
collected during a sustained 4-yr bloom in Upper Laguna Madre. Simulations suggested that light attenuation by the HAB could
cause a small reduction inT. testudinum biomass, while input of organic matter from the bloom could promote development of a sediment geochemical environment toxic
toT. testudinum leading to a major reduction in biomass. A 3-wk dredging event resulted in sedimentation of a layer of rich organic material
and reduction of canopy light for a period of months. The simulations suggested that the seagrass could have recovered from
the effects of temporary light reduction but residual effects of high sulfides in the sediments would make the region inhospitable
for seagrasses for up to 2.5 yr. These modeling exercises illustrate that both natural and anthropogenic stressors can result
in seagrass losses by radically altering the sedimentary geochemical environment. 相似文献