The Wilhelmøya Formation (Upper Triassic-Lower Jurassic) at Bohemanflya, Spitsbergen     

HENNING DYPVIK  SVEN HVOSLEF  TOR BJ/ERKE  EGIL FINNERUD 《Polar research》1985,3(2):155-165

An 18.5 m thick shale sequence of Norian-Rhaetian age is described from the Bohemanfiya-Syltoppen area (north of Isfjorden, central Spitsbergen). Lithological, petrographical and palynological analyses show that the sequence represents a marginal development of the lower part of the Wilhelmeya Formation. The depositional history at the Triassic-Jurassic transition is discussed in the light of this new evidence. The Wilhelmøya Formation was probably deposited during a weak marine transgression over an area of low relief. Low sediment supply and current and wave reworking of the sediments characterized the depositional conditions.  相似文献   

Dynamic sea-level change during the last deglaciation of northern Iceland     

MATS RUNDGREN  ÓLAFUR INGÓLFSSON  SVANTE BJÖRCK  HUI JIANG  HAFLIDI HAFLIDASON 《Boreas: An International Journal of Quaternary Research》1997,26(3):201-215

Rundgren, M., Ingólfsson, Ó., Björck, S., Jiang, H. & Haflioason, H. 1997 (September): Dynamic sea-level change during the last deglaciation of northern Iceland. Boreas , Vol. 26, pp. 201–215. Oslo. ISSN 0300–9483.
A detailed reconstruction of deglacial relative sea-level changes at the northern coast of Iceland, based on the litho- and biostratigraphy of lake basins, indicates an overall fall in relative sea level of about 45 m between 11300 and 9100 BP, corresponding to an isostatic rebound of 77 m. The overall regression was interrupted by two minor transgressions during the late Younger Dryas and in early Preboreal, and these were probably caused by a combination of expansions of local ice caps and readvances of the Icelandic inland ice-sheet margin. Maximum absolute uplift rates are recorded during the regressional phase between the two transgressions (10000–9850 BP), with a mean value of c . 15 cm ¹⁴C yr^-1 or 11–12 cm cal. yr^-1. Mean absolute uplift during the regressional phase following the second transgression (9700–9100 BP) was around 6 cm ¹⁴C yr^-1, corresponding to c . 3 cm cal. yr^-1, and relative sea level dropped below present-day sea level at 9000 BP.  相似文献   

Revision of the early Holocene lake sediment based chronology and event stratigraphy on Hochstetter Forland, NE Greenland   总被引：1，自引：1，他引：1  

SVANTE BJÖRCK  BARBARA WOHLFARTH  OLE BENNIKE  CHRISTIAN HJORT  THOMAS PERSSON 《Boreas: An International Journal of Quaternary Research》1994,23(4):513-523

The previously established and often debated lake sediment based chronology and event stratigraphy from Hochstetter Forland, NE Greenland, has been re-examined. These new studies show that the last deglaciation of the coastal area is several thousand years younger than previously described. The main reason behind the difference is the fact that the older chronology was based on ¹⁴C datings of bulk sediment samples, which are now shown to contain enough coal fragments to produce erroneous ages. The re-examination was performed on sediments from two lakes located within the Nanok moraine system: one is situated at or slightly above the marine limit around 65 m. the other at 21–22 m a.s.l. The combined stratigraphy from the two lakes shows that the area was deglaciated before 9000 BP, after which followed deposition of glaciomarine sediments, fining upwards. The first vegetation seems to have been dominated by grasses, Lycopodium and Polypodiaceae. At c . 8000 BP the limnic production increased significantly and a pioneer vegetation characterized the area. At this time the 'Artemisia' grains appear. A short but distinct climatic cooling occurs at c . 7500 BP causing a significant drop in lake productivity and possibly also producing coarser sediments in the (glacio)marine environment. About 200 years later the lake productivity again increased, very rapidly, and the marine sediments became finer and more rich in molluscs, as a response to the beginning of the climatic optimum. Because of the time-lag between climate and vegetation response it took another 300 years before Betulci nana immigrated, at the same time as the 'Artemisia' grains disappeared, and another several hundred years before a real dwarf-shrub vegetation developed in these parts of Hochstetter Forland. Before the lower lake was isolated from the sea at c . 6000 BP, coarse wave-washed sediments, followed by a typical isolation sequence, were deposited in it.  相似文献   

Holocene shore displacement and deglaciation chronology in Norrbotten, Sweden   总被引：1，自引：0，他引：1  

MATTIAS LINDÉN  PER MÖLLER  SVANTE BJÖRCK  PER SANDGREN 《Boreas: An International Journal of Quaternary Research》2006,35(1):1-22

The coastal zone of Norrbotten, northern Sweden, was gradually inundated by the Ancylus Lake following the retreating ice margin and forming a highest coastline approximately 210 m above the present sea level. The succeeding shore displacement is reconstructed based on lithological investigations and radiocarbon datings of identified isolation sequences from 12 cored lake basins. The highest lake basins, along with two basins above the highest shoreline, suggest ice-free conditions already at 10 500 cal. yr BP. This is at least 500 years earlier than previously thought and implies rapid ice-sheet break-up in the Gulf of Bothnia. The shore displacement (RSL) curve represents a forced regression of successively decreasing rate through the Holocene, from 9 m/100 yr to 0.8 m/100 yr. During the first 1000-1200 years, the isostatic uplift is exponentially declining, followed by a constant uplift rate from c. 9500 cal. yr BP to 5500-5000 cal. yr BP. The last 5000 years seem to be characterized by a low but constant rebound rate. The development of the Ancylus Lake stage of the Baltic may also be discerned in the Norrbotten RSL curve, suggesting that the chronology of the Ancylus Lake stages may have to be revised. The Littorina transgression is also reflected by the RSL curve shape. In addition, a series of early to mid-Holocene beach terraces were OSL-dated to allow for comparison with the ¹⁴C-dated shore displacement curve. Interpretations of these ages and their relation to former sea levels were clearly more problematic than the dating of the lake basin isolations.  相似文献   

Challenging problems in land-sea interactions     

SVANTE BJÖRCK  NILS-OLOF SVENSSON 《Boreas: An International Journal of Quaternary Research》1992,21(2):190-191

Book reviewed in this article:
Sabadini. R., Lambeck, K. & Boschi, E. (eds.) 1991: Glacial Isostas, Sea-Level and Mantle Rheology  相似文献   

DEDICATED PRINCIPAL PROPERTIES FOR PEPTIDE QSARS: THEORY AND APPLICATIONS     

BERTSKAGERBERG  MICHAEL  SVANTEWOLD 《地理学报(英文版)》1990,(3)

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Storegga tsunami deposits in a coastal lake on Suouroy, the Faroe Islands     

MARIANNE GRAUERT  SVANTE BJÖRCK  STEIN BONDEVIK 《Boreas: An International Journal of Quaternary Research》2001,30(4):263-271

Presumed deposits of the Storegga tsunami have been recognized in a coastal lake situated 4 m a.s.l. on the island of Suðuroy, the Faroe Islands. The stratigraphy in the lake reveals a major erosion and redepositional event. The deposited material ranges from sand and sandy gyttja, with marine shell fragments and foraminifera, to gyttja with rip-up clasts, wood fragments and thin sand layers. Diatom analysis indicates that the deposit contains 5-8% polyhalobous (full marine) species, decreasing to 1-2% in the undisturbed lacustrine gyttja above. The tsunami event was dated to some time between 7300 and 6400 14 C yr BP. Lithostratigraphic profiles in the lake suggest that at least two large waves inundated the basin. The first and largest wave eroded most or all of the sediments previously deposited in the basin. The next wave caused minor erosion of the redeposited material. The waves deposited two generations of sand overlain by organic conglomerates, after which followed a unit of suspension material and normal lacustrine gyttja.  相似文献   

Late Quaternary glacial history of the central west coast of Jameson Land, East Greenland     

ÓLAFUR INGÓLFSSON  ASTRID LYSÅ  SVEND FUNDER  PER MÖLLER  SVANTE BJÖRCK 《Boreas: An International Journal of Quaternary Research》1994,23(4):447-458

The Late Quaternary ( c . 130,000–10,000 BP) glacial history of the central west coast of Jameson Land, East Greenland, is reconstructed through glacial stratigraphical studies. Seven major sedimentary units are described and defined. They represent two interglacial events (where one is the Holocene). one interstadial event and two glacial events. The older interglacial event comprises marine and fluvial sediments, and is correlated to the Langelandselv interglacial, corresponding to oxygen isotope sub-stage 5e. It is followed by an Early Weichselian major glaciation during the Aucellaelv stade, and subsequently by an Early Weichselian interstadial marine and deltaic event (the Hugin Sø interstade). Sediments relating to the Middle Weichselian have not been recognized in the area. The Hugin Sø interstade deposits have been overrun by a Late Weichselian ice advance, during the Flakkerhuk stade, when the glacier, which probably was a thin, low gradient fjord glacier in Scoresby Sund, draped older sediments and landforms with a thin till. Subsequent to the final deglaciation, some time before 10,000BP, the sea reached the marine limit around 70 m a.s.l., and early Holocene marine, fluvial and littoral sediments were deposited in the coastal areas.  相似文献   

RELATIONSHIPS BETWEEN HIGHER-ORDER DATA ARRAY CONFIGURATIONS AND PROBLEM FORMULATIONS IN MULTIVARIATE DATA ANALYSIS   总被引：1，自引：0，他引：1  

KIM.H.ESBENSEN  SVANTE WOLD  PAUL GELADI 《地理学报(英文版)》1988,(1)

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Palaeomagnetic records from two varved clay sequences in the Middle Swedish ice marginal zone     

PER SANDGREN  SVANTE BJÖRCK  LARS BRUNNBERG  JAN KRISTIANSSON 《Boreas: An International Journal of Quaternary Research》1988,17(2):215-227

Two varved clay sequences, at Rystad and Tottnäs, situated in the Middle Swedish ice marginal zone were analysed palaeomagnetically. Two parallel profiles were sampled and analysed at each site. The varved clay at Rystad was dated by floating varve chronology. The varves at Tottnäs can be linked to Swedish time scale, expressed in calendar years B.P. Due to the distance between the sites they cannot be correlated by means of varve diagrams. Palaemagnetic methods were used as an alternative. Based an AF demanetization of pilot samples, the palaeomanetic to be too low, in the order of15, compared to the site latitude. At Tottnäs the inclination records are very close to the expected inclination with respect to the site latitude. Because of a systematic inclination error in the Rystad profiles the correlation was based on the declination records. Statistical comparisons of these records between the two sites indicate that the sediment successions are partly synchronous. It is concluded that the deglaciation at Tottnäs started c. 130 years earlier than at Rystad. This mean that the Swedish ice marginal zone east of Rystad will have a more northeasterly extension than previously thought.  相似文献