Late Cenozoic depositional history of the western Svalbard continental shelf, controlled by subsidence and climate     

A. Solheim  E. S. Andersen  A. Elverhi  A. Fiedler 《Global and Planetary Change》1996,12(1-4)

Based on a grid of high resolution, single channel seismic lines, this paper addresses the Late Cenozoic evolution of the western Svalbard continental shelf. The seismic structure of the shelf includes at least 16 erosional unconformities, each representing a glacial advance. The evolution during the last approximately one million years has been divided into six main erosional and depositional phases. Differential margin subsidence around a hinge zone is an important controlling mechanism for the accumulation of the sedimentary wedge at the outer shelf. The most significant depositional change appears to be related to a general climatic shift, globally recorded to be centred around 1 Ma. At this level, corresponding to the Upper Regional Unconformity (URU) on the shelf, the depositional regime changed from net erosion to net deposition and shelf aggradation. Of major significance is probably a shift from thick, eroding glaciers with steep ice profiles, to low profile fast flowing ice streams maintained by an increased amount of interglacial and interstadial sediments. The relationship between climatic fluctuations, glacial dynamics and depositional regime is discussed.  相似文献   

Towards a 4D topographic view of the Norwegian sea margin   总被引：1，自引：1，他引：0  

Morten Smelror  John Dehls  Jrg Ebbing  Eiliv Larsen  Erik R. Lundin   ystein Nordgulen  Per Terje Osmundsen  Odleiv Olesen  Dag Ottesen  Christophe Pascal  Thomas F. Redfield  Leif Rise 《Global and Planetary Change》2007,58(1-4):382

The present-day topography/bathymetry of the Norwegian mainland and passive margin is a product of complex interactions between large-scale tectonomagmatic and climatic processes that can be traced back in time to the Late Silurian Caledonian Orogeny. The isostatic balance of the crust and lithosphere was clearly influenced by orogenic thickening during the Caledonian Orogeny, but was soon affected by post-orogenic collapse including overprinting of the mountain root, and was subsequently affected by a number of discrete extensional events eventually leading to continental break-up in Early Eocene time. In the mid-Jurassic the land areas experienced deep erosion in the warm and humid climate, forming a regional paleic surface. Rift episodes in the Late Jurassic and Early Cretaceous, with differential uplift along major fault zones, led to more pronounced topographic contrasts during the Cretaceous, and thick sequences of clastic sediments accumulated in the subsiding basins on the shelf. Following renewed extension in the Late Cretaceous, a new paleic surface developed in the Paleocene. Following break-up the margin has largely subsided thermally, but several Cenozoic shortening events have generated positive contraction structures. On the western side of the on-shore drainage divide, deeper erosion took place along pre-existing weakness zones, creating the template of the present day valleys and fjords. In the Neogene the mainland and large portions of the Barents Sea were uplifted. It appears that this uplift permitted ice caps to nucleate and accumulate during the Late Pliocene northern hemisphere climatic deterioration. The Late Pliocene to Pleistocene glacial erosion caused huge sediment aprons to be shed on to the Norwegian Sea and Barents Sea margins. Upon removal of the ice load the landmass adjusted isostatically, and this still continues today.  相似文献   

Foreword     

Ole B. Andersen 《Journal of Geodesy》2004,77(10-11):559-559

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HAXTEL: A Laue lens telescope development project for a deep exploration of the hard X-ray sky (> 60 keV)     

F. Frontera  A. Pisa  G. Loffredo  D. Pellicciotta  V. Carassiti  F. Evangelisti  K. Andersen  P. Courtois  L. Amati  E. Caroli  T. Franceschini  G. Landini  S. Silvestri  J. Stephen 《Experimental Astronomy》2005,20(1-3):241-251

A review of the HAXTEL project devoted to the development of a Laue lens telescope for hard X-/gamma-ray observation of the continuum spectra of celestial sources is presented. Main design properties, open issues, the status of the project and an example of multi-lens configuration with sensitivity expectations are discussed.  相似文献   

High‐resolution reconstruction of a coastal barrier system: impact of Holocene sea‐level change          下载免费PDF全文

Mikkel Fruergaard  Thorbjørn J. Andersen  Lars H. Nielsen  Peter N. Johannessen  Troels Aagaard  Morten Pejrup 《Sedimentology》2015,62(3):928-969

This study presents a detailed reconstruction of the sedimentary effects of Holocene sea‐level rise on a modern coastal barrier system. Increasing concern over the evolution of coastal barrier systems due to future accelerated rates of sea‐level rise calls for a better understanding of coastal barrier response to sea‐level changes. The complex evolution and sequence stratigraphic framework of the investigated coastal barrier system is reconstructed using facies analysis, high‐resolution optically stimulated luminescence and radiocarbon dating. During the formation of the coastal barrier system starting 8 to 7 ka rapid relative sea‐level rise outpaced sediment accumulation. Not before rates of relative sea‐level rise had decreased to ca 2 mm yr^?1 did sediment accumulation outpace sea‐level rise. From ca 5·5 ka, rates of regionally averaged sediment accumulation increased to 4·3 mm yr^?1 and the back‐barrier basin was filled in. This increase in sediment accumulation resulted from retreat of the barrier island and probably also due to formation of a tidal inlet close to the study area. Continued transgression and shoreface retreat created a distinct hiatus and wave ravinement surface in the seaward part of the coastal barrier system before the barrier shoreline stabilized between 5·0 ka and 4·5 ka. Back‐barrier shoreline erosion due to sediment starvation in the back‐barrier basin was pronounced from 4·5 to 2·5 ka but, in the last 2·5 kyr, barrier sedimentation has kept up with and outpaced sea‐level. In the last 0·4 kyr the coastal barrier system has been prograding episodically. Sediment accumulation shows considerable variation, with periods of rapid sediment deposition and periods of non‐deposition or erosion resulting in a highly punctuated sediment record. The study demonstrates how core‐based facies interpretations supported by a high‐resolution chronology and a well‐documented sea‐level history allow identification of depositional environments, erosion surfaces and hiatuses within a very homogeneous stratigraphy, and allow a detailed temporal reconstruction of a coastal barrier system in relation to sea‐level rise and sediment supply.  相似文献   

Understanding connected surface-water/groundwater systems using Fourier analysis of daily and sub-daily head fluctuations     

R. I. Acworth  Gabriel C. Rau  Andrew M. McCallum  Martin S. Andersen  Mark O. Cuthbert 《Hydrogeology Journal》2015,23(1):143-159

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IAG Newsletter     

Ole Baltazar Andersen 《Journal of Geodesy》2001,74(9):672-682

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Magneto-Telluric Experiments in Northern Ellesmere Island     

K. Whitham  F. Andersen 《Geophysical Journal International》1965,10(3):317-345

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A precise multipass method for satellite Doppler positioning     

K. Aksnes  P. H. Andersen  E. Haugen 《Celestial Mechanics and Dynamical Astronomy》1988,44(4):317-338

A precise and efficient algorithm is developed for determining the locations of radio beacons (e.g. of the ARGOS or COSPAS/SARSAT type) based on Doppler shift measurements in overflying satellites. The method distinguishes itself through: (1) the use of a very compact analytic orbital theory valid for all eccentricities, (2) autonomous orbit improvement based on Doppler data for one or more local reference beacons accessible at a single LUT, (3) simultaneous orbit improvement and calculation of beacon coordinates for an arbitrary number of satellites, satellite passes, and beacons, and (4) very efficient semi-analytic matrix inversion by partitioning into global, semi-global, and local parameters.The algorithm has been implemented in a FORTRAN program which can be run on a PC. Error statistics are presented from applications of the program to a large number of actual Doppler curves obtained with the ARGOS and COSPAS/SARSAT systems.  相似文献   

Challenges in global ballast water management   总被引：3，自引：0，他引：3  

Endresen Ø  Lee Behrens H  Brynestad S  Bjørn Andersen A  Skjong R 《Marine pollution bulletin》2004,48(7-8):615-623

Ballast water management is a complex issue raising the challenge of merging international regulations, ship's specific configurations along with ecological conservation. This complexity is illustrated in this paper by considering ballast water volume, discharge frequency, ship safety and operational issues aligned with regional characteristics to address ecological risk for selected routes. A re-estimation of ballast water volumes gives a global annual level of 3500 Mton. Global ballast water volume discharged into open sea originating from ballast water exchange operations is estimated to approximately 2800 Mton. Risk based decision support systems coupled to databases for different ports and invasive species characteristics and distributions can allow for differentiated treatment levels while maintaining low risk levels. On certain routes, the risk is estimated to be unacceptable and some kind of ballast water treatment or management should be applied.  相似文献