Determining the climatic boundary between the Chinese loess and palaeosol: evidence from aeolian coarse-grained magnetite   总被引：3，自引：0，他引：3  

Qingsong Liu  Subir K. Banerjee  Michael J. Jackson  Fahu Chen  Yongxin Pan  Rixiang Zhu 《Geophysical Journal International》2004,156(2):267-274

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Love's problem     

Janet M. Becker  Michael Bevis 《Geophysical Journal International》2004,156(2):171-178

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Stress-induced temporal variations in seismic anisotropy observed in microseismic data   总被引：2，自引：0，他引：2  

N. Teanby  J.-M. Kendall  R. H. Jones  O. Barkved 《Geophysical Journal International》2004,156(3):459-466

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Pollution history and recovery of a boreal lake exposed to a heavy bleached pulping effluent load   总被引：4，自引：0，他引：4  

Juhani Hynynen  Arja Palomäki  Jarmo J. Meriläinen  Allan Witick  Keijo Mäntykoski 《Journal of Paleolimnology》2004,32(4):351-374

We examined the effects of heavy pulp mill discharges on the Lake Lievestuoreenjärvi ecosystem and the later recovery of diatom and chironomid communities from age-dated short core samples. Beginning in 1927 the lake received a heavy effluent load from a sulphite pulp mill. Except for the recession during the Second World War and the temporary closure of the mill from 1967 to 1971, the industrial load, containing large quantities of nutrients, organic matter and toxic compounds, increased continuously. In the early 1980s, laboratory documents were falsified by the directors of the mill and the systematic illegal effluent overload led to a collapse of the whole lake ecosystem. In 1985, the outdated plant was finally closed down. Based on the assessment of chemical properties and biological remains of the sediment, we distinguished five developmental phases in the ecological state of the lake. In the pre-industrial phase, the pelagic and profundal benthic communities were dominated by species preferring ultraoligotrophic or oligotrophic lakes. Concomitant with the increasing discharge and deposition of chlorine compounds, resin acids, and mercury, as well as strong acidity and hypolimnetic and epilimnetic anoxia, the ecological status changed in a short period from excellent to bad. Finally, in the early 1960s, the majority of the lake was virtually dead and the aquatic life survived only in the uppermost littoral zone. Since 1985, a fast recovery in the water quality has led to a strong, but temporary eutrophy in pelagic communities. The main peak of eutrophication was caused by the invasion of a species new to the lake,Aulacoseira granulata var.angustissima. Later, the pelagic communities shifted towards oligotrophy, but the original, pre-industrial status has not been re-established. The profundal benthic communities have not achieved the pre-industrial structure, but at present indicate mesotrophy.  相似文献   

Automatic Road Change Detection and GIS Updating from High Spatial Remotely-Sensed Imagery     

ZHANGQiaoping IsabelleCouloigner 《地球空间信息科学学报》2004,7(2):89-95

This paper presents a tramework for road network change detectlon In order to upctate the Canadian National Topographic DataBase (NTDB). The methodology has been developed on the basis of road extraction from IRS-pan images (with a 5.8 m spatial resolution) by using a wavelet approach. The feature matching and conflation techniques are used to road change detection and updating. Elementary experiments have showed that the proposed framework could be used for developing an operational road database updating system.  相似文献   

Data Fusion in Distributed Multi-sensor System   总被引：5，自引：0，他引：5  

GUOHang YUMin 《地球空间信息科学学报》2004,7(3):214-217

This paper presents a data fusion method in distributed multi-sensor system including GPS and INS sensors“ data processing. First, a residual X^2-test strategy with the corresponding algorithm is designed.Then a coefficient matrices calculation method of the information sharing principle is derived. Finally, the federated Kalman filter is used to combine these independent, parallel, real-time data. A pseudolite (PL) simulation example is given.  相似文献   

Coastal processes and cliff recession between Gabicce and Pesaro (northern Adriatic Sea): a case history     

P. Colantoni  D. Mencucci  O. Nesci   《Geomorphology》2004,62(3-4):257-268

Cliff recession on the high rocky coast between Gabicce and Pesaro Adriatic sea causes a wide range of mass movement processes on the whole slope, affecting both the bedrock and the overburden. The outcropping late Miocene rock formations are represented by marls, marly limestones, dark laminated mudstones and bedded sandstones and marls. Mass movements are common because of stratification and discontinuities in the rocks that, together with the presence of groundwater and weathering processes, reduce the overall strength of the slopes. A model for the evolution of this coastal area is proposed, which involves cyclic basal erosion, followed by mass movement that favours debris accumulation at the base of the cliff. The longshore currents have to then remove the material before a new cycle can begin.  相似文献   

Record of Late Pleistocene Glaciation and Deglaciation in the Southern Cascade Range. I. Petrological Evidence from Lacustrine Sediment in Upper Klamath Lake, Southern Oregon     

Richard L. Reynolds  Joseph G. Rosenbaum  Josh Rapp  Michael W. Kerwin  J. Platt Bradbury  Steven Colman  David Adam 《Journal of Paleolimnology》2004,31(2):217-233

Petrological and textural properties of lacustrine sediments from Upper Klamath Lake, Oregon, reflect changing input volumes of glacial flour and thus reveal a detailed glacial history for the southern Cascade Range between about 37 and 15 ka. Magnetic properties vary as a result of mixing different amounts of the highly magnetic, glacially generated detritus with less magnetic, more weathered detritus derived from unglaciated parts of the large catchment. Evidence that the magnetic properties record glacial flour input is based mainly on the strong correlation between bulk sediment particle size and parameters that measure the magnetite content and magnetic mineral freshness. High magnetization corresponds to relatively fine particle size and lower magnetization to coarser particle size. This relation is not found in the Buck Lake core in a nearby, unglaciated catchment. Angular silt-sized volcanic rock fragments containing unaltered magnetite dominate the magnetic fraction in the late Pleistocene sediments but are absent in younger, low magnetization sediments. The finer grained, highly magnetic sediments contain high proportions of planktic diatoms indicative of cold, oligotrophic limnic conditions. Sediment with lower magnetite content contains populations of diatoms indicative of warmer, eutrophic limnic conditions. During the latter part of oxygen isotope stage 3 (about 37–25 ka), the magnetic properties record millennial-scale variations in glacial-flour content. The input of glacial flour was uniformly high during the Last Glacial Maximum, between about 21 and 16 ka. At about 16 ka, magnetite input, both absolute and relative to hematite, decreased abruptly, reflecting a rapid decline in glacially derived detritus. The decrease in magnetite transport into the lake preceded declines in pollen from both grass and sagebrush. A more gradual decrease in heavy mineral content over this interval records sediment starvation with the growth of marshes at the margins of the lake and dilution of detrital material by biogenic silica and other organic matter.  相似文献   

A deep seismic transect from Hovgård Ridge to northwestern Svalbard across the continental-ocean transition: A sheared margin study     

O. Ritzmann  W. Jokat  W. Czuba  A. Guterch  R. Mjelde  Y. Nishimura 《Geophysical Journal International》2004,157(2):683-702

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Gross thermodynamics of two-component core convection     

David Gubbins  Dario Alfè  Guy Masters  G. David Price  Michael Gillan 《Geophysical Journal International》2004,157(3):1407-1414

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