Suspension settling effect on macrobenthos biomass distribution in the Hornsund fjord, Spitsbergen   总被引：7，自引：0，他引：7  

KRZYSZTOF GORLICH  JAN M. WESTAWSKI  MAREK ZAJACZKOWSKI 《Polar research》1987,5(2):175-192

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The deglaciation of Scandinavia later than 10,000 B.P.: The 1979 Uppsala Symposium     

JAN LUNDQVIST  LARS-KÖNIG KÖNIGSSON 《Boreas: An International Journal of Quaternary Research》1980,9(4):209-210

The 1979 Uppsala Symposium was arranged as a continuation of the symposium held in Uppsala in 1978 on the deglaciation of Scandinavia earlier than 10,000 B.P. Papers from the latter symposium were published in Boreas , Vol. 8, No. 2 (1979). In the present issue, eleven contributions from the 1979 Symposium are included, among them three general summaries for Norway, Finland, and Sweden. The Symposium and this issue of Boreas form part of the joint Nordic activity within the IGCP project entitled 'Quaternary Glaciations in the Northern Hemisphere'  相似文献   

Glacier mass balance investigations in the balance years 1984-85 and 1985-86     

JON OVE HAGEN  OLAV LIESTØL 《Polar research》1987,5(2):261-265

As in previous years Norsk Polarinstitutt has carried out mass balance investigations on Storbreen and Hardangerjøkulen in mainland Norway and on Broggerbreen and Lovenbreen in Svalbard. More than 20 years of measurements show that the glaciers both in mainland Norway and in Svalbard are retreating.
Both in 1985 and in 1986 the glaciers in Norway had a negative net balance. At Storbreen the mean annual net balance value 1949-86 is -0.30 m in water equivalents, while on Hardangerjflkulen the mean value 1963-86 is -0.02 m.
The two glaciers measured in Svalbard also had negative net balance in 1985 and in 1986. Both measured glaciers have had negative balance nearly all years since the measurements started in 1966. The mean value is close to -40g/cm² or -0.4 m on both.  相似文献   

Progress in the Gondwanan Carboniferous–Permian palynology and correlation of the Nilawahan Group of the Salt Range,Pakistan: A brief review     

IRFAN U JAN 《Journal of Earth System Science》2014,123(1):21-32

This paper comprises of two sections. The first section describes challenges in the Carboniferous–Permian Gondwanan stratigraphic palynology, and progress in techniques such as presence of the ‘rare-marine intervals’, and ‘radiometric dating’ in some Gondwanan successions, e.g., South Africa, Australia and South America, as tools to confidently calibrate these palynozones. The second section describes developments in the palynological work on the Carboniferous–Permian Nilawahan Group of the Salt Range, Pakistan, and summarises their correlation with the coeval succession of the Gondwana continents and with the Russian/International stages.  相似文献   

Design of a spatial data structure using the relational normal forms     

JAN W. VAN ROESSEL 《International journal of geographical information science》2013,27(1):33-50

Abstract

In previous work, a relational data structure aimed at the exchange of spatial data between systems was developed. As this data structure was relational it was of first normal form, but compliance with the higher normal forms was not investigated. Recently, a new procedural method for composing fully normalized data structures from the basic data fields has been developed by H. C. Smith, as an alternative to the process of non-loss decomposition which is difficult to understand. Smith's method has been applied to data fields required to store points, lines and polygons in a chain-node spatial data model. When geographic domain, coverage layer and map are also considered, the procedure naturally leads to a catalogue model, needed for the exchange of spatial data. Although the method produces a fully normalized data structure, it is not as easy to identify which normal forms are responsible for the ultimate arrangement of the data fields into relations, but the benefits of these criteria for data base development also apply to spatial data structures and related ancillary data.  相似文献   

LAND USE DEVELOPMENT IN GREATER COPENHAGEN     

JAN MAGNUSSEN M.Sc.  CHR. W. MATTHIESSEN Ph.D. 《Geografisk tidskrift / udgivet af Bestyrelsen for Det Kongelige danske geografiske selskab》2013,113(1):65-69

Magnussen, Jan and Wichmann Matthiessen, Chr.: Land Use Development in Greater Copenhagen. Geografisk Tidsskrift 75: 65–69. København, juni 1, 1976.

The paper attempts to elucidate the land use development within Greater Copenhagen during this century. Sequences expressing the intensification of use und the process of urban renewal are the objects of the analysis.  相似文献   

Geochemistry of Holocene salt marsh and tidal flat sediments on a barrier island in the southern North Sea (Langeoog,North‐west Germany)     

KERSTIN KOLDITZ  OLAF DELLWIG  JAN BARKOWSKI  RAINER BAHLO  THOMAS LEIPE  HOLGER FREUND  HANS‐JÜRGEN BRUMSACK 《Sedimentology》2012,59(2):337-355

The barrier islands of the southern North Sea were formed during the Holocene sea‐level rise. These islands form part of a highly dynamic environment whose evolution continues today. Subjected to sea‐level changes, tides and storm events, the sedimentary record reflects processes occurring under varying energy conditions. This article presents geochemical, mineralogical and diatom investigations carried out in the salt marsh of the East Frisian barrier island of Langeoog, which is re‐exposed to a rising sea‐level due to de‐embankment. The major aim of this study is to improve the knowledge of the sedimentological and geochemical development of these deposits under the influence of sea‐level rise, with a special focus on the geochemistry and distribution of heavy mineral‐associated elements. Correlation diagrams between FeO, TiO₂ and MnO, as well as ternary plots (Al₂O₃–SiO₂–Zr or TiO₂), clearly indicate the variable appearance of heavy minerals in different lithological facies, comprising marsh soil, mixed and sand flat, and relocated beach sands. A dominating abundance of ilmenite followed by zircon, garnets and some other heavy minerals is evidenced by Scanning Electron Microscope‐Energy Dispersive X‐ray measurements. The data presented here suggests that these geochemical proxies are useful tools for characterizing depositional energy conditions. Increasing depositional energy is evident for the lithological units in the following order: marsh soil, mixed flat, sand flat and relocated beach sand. The energetic conditions during sediment deposition, as well as the sedimentary history, are confirmed by diatom analyses as an additional independent indicator. Depending on source rock composition, the geochemical parameters used in this study may also help to investigate depositional energy regimes of other siliciclastic sedimentary systems.  相似文献   

Tsunami backwash deposits with Chicxulub impact ejecta and dinosaur remains from the Cretaceous–Palaeogene boundary in the La Popa Basin,Mexico     

PETER SCHULTE  JAN SMIT  ALEXANDER DEUTSCH  TOBIAS SALGE  ANDREA FRIESE  KILIAN BEICHEL 《Sedimentology》2012,59(3):737-765

The La Popa Basin in north‐eastern Mexico features outstanding, continuous three‐dimensional exposures of the Cretaceous–Palaeogene boundary event deposit in shallow shelf environments pierced by salt stocks. In the area to the south‐east of the El Papalote diapir, the Cretaceous–Palaeogene deposit consists of two superimposed sedimentary units and erosively overlies upper Maastrichtian sand‐siltstones with soft‐sediment deformation and liquefaction structures. The basal unit 1 is an up to 8 m thick chaotic, carbonate‐rich bed that discontinuously fills incised gutters and channels. Besides abundant silicic and carbonate ejecta spherules from the Chicxulub impact, unit 1 includes large sandstone boulders and abundant shallow‐water debris (for example, mud clasts, algae, bivalve shells, gastropod shells and vertebrate remains). Unit 1 is conformably overlain by unit 2. Distal to the diapir, unit 2 consists of a centimetre to decimetre‐thick conglomeratic, coarse bioclast and spherule‐bearing sandstone bed. Closer to the diapir, unit 2 becomes a metre‐thick series of four to eight conglomeratic to fine‐grained graded sandstone beds rich in shell debris and ejecta spherules. Unit 2 is conformably overlain by structureless to parallel laminated sandstone beds that may mark the return to the pre‐event depositional regime. The sedimentary characteristics of the Cretaceous–Palaeogene deposit, including its erosive base, its sheet‐like geometry, the presence of multiple, graded beds, evidence for upper flow regime conditions and the absence of bioturbation, support an origin by a short‐term multiphase depositional event. The occurrence of soft‐sediment deformation structures (for example, liquefaction) below the Cretaceous–Palaeogene deposit suggests that earthquakes were the first to occur at La Popa. Then, shelf collapse and strong backflow from the first tsunami waves may have triggered erosion and deposition by violent ejecta‐rich hyperconcentrated density flows (unit 1). Subsequently, a series of concentrated density flows resulting from tsunami backwash surges may have deposited the multiple‐graded bedding structures of unit 2. The specific depositional sequence and the Fe‐Mg‐rich as well as Si‐K‐rich composition of the ejecta spherules both provide a critical link to the well‐known deep marine Cretaceous–Palaeogene boundary sites in the adjacent Burgos basin in north‐eastern Mexico. Moreover, the pulse‐like input of Chicxulub ejecta material at the base of the event deposit allows for correlation with other Cretaceous–Palaeogene boundary sites in the Gulf of Mexico and the Atlantic, as well as in Central and Northern America. The presence of diverse dinosaur and mosasur bones and teeth in the event deposit is the first observation of such remains together with Chicxulub ejecta material. These findings indicate that dinosaurs lived in the area during the latest Maastrichtian and suggest that the tsunami waves not only eroded deltas and estuaries but the coastal plain as well.  相似文献   

“Stratigraphic,sedimentological and palaeoenvironmental constraints on the rise of the Urgonian platform in the western Swiss Jura” by A. Godet et al. (2010) Sedimentology 57, 1088–1125: Discussion     

MARC A. CONRAD  BERNARD CLAVEL  BRUNO GRANIER  JEAN CHAROLLAIS  ROBERT BUSNARDO  ELISABETTA ERBA  SILVIA GARDIN  ROGER JAN DU CHÊNE  DANIELLE DECROUEZ  ANTONIETTA CHERCHI  ROLF SCHROEDER  JACQUES SAUVAGNAT  MARC WEIDMANN 《Sedimentology》2012,59(3):1121-1125

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长江上游蒋家沟泥石流输沙年际变化与降水旋回特征关系   总被引：1，自引：0，他引：1  

王裕宜  詹钱登  田冰  洪勇  邹仁元 《山地学报》2008,26(5)

根据小不流域1956～2002年的降水资料,运用Mann-Kendall(M-K)非参数检验法和自相关函数,发现1990代降水旱现显著增加的趋势,其降水年均值比前期年均值增加96.5 mm(16.2%).并结合37 a气候变化下的蒋家沟高频率暴雨泥石流输沙最时序观测资料,分析了降雨变化与泥石流输沙量的关系,结果显示1990年代泥石流输沙量有显著增加的趋势,1990年代的年均输沙量比前期(1965～1989年)的年均输沙量多91×104m3/a.反映了暴雨泥石流输沙年际变率对降水年际变化的回应关系.本文已经初步揭示暴雨泥石流灾害活动年际变化的基本规律,并且为未来暴雨泥石流中、短期时间尺度的预测研究提供一条新路.  相似文献