Aspects of the Weichselian chronology in central East Greenland     

SVEND FUNDER  CHRISTIAN HJORT 《Boreas: An International Journal of Quaternary Research》1973,2(2):69-84

From central East Greenland, C₁₄ ages between 19,500 > 40,000 years B.P. have been obtained for six samples of marine bivalve shells. The ages seem to be consistent with geological observations and form the basis for a tentative chronology for the Weichselian ice age in the region. It appears that the maximum glaciation during Weichselian times was attained more than 40,000 years ago, and that since then ice-free areas have existed. This assumption agrees with evidence of botanical refugia in the region, and the restricted glacier activity especially during the Upper Pleniglacial (ca. 30,000–15,000 years B.P.) is explained by a reduced supply of moisture. A comparison with evidence from other parts of Greenland indicates that different glacial histories can be expected for different sectors of the Greenland Inland Ice.  相似文献   

Radiocarbon dated common mussels Mytilus edulis from eastern Svalbard and the Holocene marine climatic optimum     

CHRISTIAN HJORT  JAN MANGERUD  LENA ADRIELSSON  STEIN BONDEVIK  JON Y. LANDVIK  OTTO SALVIGSEN 《Polar research》1995,14(2):239-243

The common mussel Mytilus edulis is an indicator of milder marine conditions in the Arctic, with stronger Atlantic Water influx, during the Holocene and earlier interglacials. Twelve Holocene radiocarbon dates of mytilus from eastern Svalbard fall between ca 8800 and 5000 BP and roughly delimit the marine climatic optimum period there. The beginning of this period in the east coincides with the immigration of boreal extralimital molluscs to western Svalbard, indicating the culmination of Holocene Atlantic influence.  相似文献   

Distinguishing fluvio‐deltaic facies by bulk geochemistry and heavy minerals: an example from the Miocene of Denmark     

METTE OLIVARIUS  ERIK S. RASMUSSEN  VOLKERT SIERSMA  CHRISTIAN KNUDSEN  GUNVER K. PEDERSEN 《Sedimentology》2011,58(5):1155-1179

  相似文献   

Weather influence on passive microwave brightness temperatures     

STIG M. LøVAS  IRENE RUBINSTEIN  CHRISTIAN ULSTAD 《Polar research》1994,13(1):67-81

  相似文献   

The Quaternary of the Kattegat area, Scandinavia: a review   总被引：1，自引：0，他引：1  

HOLGER LYKKE-ANDERSEN  KAREN LUISE KNUDSEN  CHRISTIAN CHRISTIANSEN 《Boreas: An International Journal of Quaternary Research》1993,22(4):269-281

The Quaternary sedimentary history and its relations to the pre-Quaternary in the Kattegat region are reviewed. The Quaternary in the area is restricted to relatively young sediments, including scattered findings of Saalian deposits and more continuous occurrences from the Eemian, the Weichselian and the Holocene. Glacial and interglacial palaeoenvironmental reconstructions, including Holocene changes in oceanographic circulation, are reviewed, and the recent sedimentary processes and the present hydrographic regime are outlined. Furthermore, Quaternary and present tectonic activity in connection with some of the pre-Quaternary fault zones is discussed.  相似文献   

Dynamics of the last glaciation in eastern Svalbard as inferred from glacier-movement indicators     

OTTO SALVIGSEN  LENA ADRIELSSON  CHRISTIAN HJORT  MICHAEL KELLY  JON Y. LANDVIK  LARS RONNERT 《Polar research》1995,14(2):141-152

Glacial striae and other ice movement indicators such as roche moutonées, glacial erratics, till fabric and glaciotectonic deformation have been used to reconstruct the Late Weichselian ice movements in the region of eastern Svalbard and the northern Barents Sea. The ice movement pattern may be divided into three main phases: (1) a maximum phase when ice flowed out of a centre east or southeast of Kong Karls Land. At this time the southern part of Spitsbergen was overrun by glacial ice from the Barents Sea; (2) the phase of deglaciation of the Barents Sea Ice Sheet, when an ice cap was centred between Kong Karls Land and Nordaustlandet. At the same time ice flowed southwards along Storfjorden; and (3) the last phase of the Late Weichselian glaciation in eastern Svalbard is represented by local ice caps on Spitsbergen, Nordaustlandet, Barentsoya and Edgeøya.
The reconstructed ice flow pattern during maximum glaciation is compatible with a centre of uplift in the northern Barents Sea as shown by isobase reconstructions and suggested by isostatic modelling.  相似文献   

Recent and subrecent sedimentary conditions in the southern part of the North Sea–Baltic Sea transition     

CHRISTIAN CHRISTIANSEN  HELMAR KUNZENDORF  CHRISTIAN OTTO  JACOB SENSTIUS 《Boreas: An International Journal of Quaternary Research》1993,22(4):357-366

The recent rate of net sedimentation (0–5mm/yr) in the southern Kattegat is to a high degree governed by resuspension. In shallow areas (10–25 m) there is no or very little sedimentation. Sediments here are sandy lag sediments with a low content of organic matter (0.5–3.0%), nitrogen (0–0.1%) and phosphorus (0.01–0.05%). In deep water (30–60 m) the sediments are clays or fine silts and generally have high contents of organic matter (3.0–10.8%), nitrogen (0.1–0.34%) and phosphorus (0.05–0.10%). Shallow water sediments are relatively well sorted because of resuspension of fine material, which is transported to deeper water. Here the sorting becomes poor because relatively coarser material is supplied during exceptional storm events. Discrimination on erosion/transport bottoms and on depositional bottoms was based on resuspension calculations, grain-size parameters and Passegas (1964) CM diagrams. The IG/N ratio was an useful additional tool. From the sediment content of CaCO₃ it is suggested that recent sedimentation in the deeper parts of southern Kattegat is less influenced by contributions from the North Sea than it was during the early Holocene.  相似文献   

Aerosol number to volume ratios in Southwest Portugal during ACE-2     

ULRIKE DUSEK  DAVID S. COVERT  ALFRED WIEDENSOHLER  CHRISTIAN NEUSÜSS  DIANA WEISE 《Tellus. Series B, Chemical and physical meteorology》2004,56(5):477-491

  相似文献   

Testing the sensitivity of the East Antarctic Ice Sheet to Southern Ocean dynamics: past changes and future implications          下载免费PDF全文

CHRISTOPHER J. FOGWILL  CHRISTIAN S. M. TURNEY  KATRIN J. MEISSNER  NICHOLAS R. GOLLEDGE  PAUL SPENCE  JASON L. ROBERTS  MATHEW H. ENGLAND  RICHARD T. JONES  LIONEL CARTER 《第四纪科学杂志》2014,29(1):91-98

  相似文献   

Late Quaternary ice sheet, lake and sea history of southwest Scandinavia – a synthesis     

NICOLAJ KROG LARSEN  KAREN LUISE KNUDSEN  CHARLOTTE FOG KROHN  CHRISTIAN KRONBORG  REW S. MURRAY  OLE BJØRSLEV NIELSEN 《Boreas: An International Journal of Quaternary Research》2009,38(4):732-761

Based on a large number of new boreholes in northern Denmark, and on the existing data, a revised event‐stratigraphy is presented for southwestern Scandinavia. Five significant Late Saalian to Late Weichselian glacial events, each separated by periods of interglacial or interstadial marine or glaciolacustrine conditions, are identified in northern Denmark. The first glacial event is attributed to the Late Saalian c. 160–140 kyr BP, when the Warthe Ice Sheet advanced from easterly and southeasterly directions through the Baltic depression into Germany and Denmark. This Baltic ice extended as far as northern Denmark, where it probably merged with the Norwegian Channel Ice Stream (NCIS) and contributed to a large discharge of icebergs into the Norwegian Sea. Following the break up, marine conditions were established that persisted from the Late Saalian until the end of the Early Weichselian. The next glaciation occurred c. 65–60 kyr BP, when the Sundsøre ice advanced from the north into Denmark and the North Sea, where the Scandinavian and British Ice Sheets merged. During the subsequent deglaciation, large ice‐dammed lakes formed before the ice disintegrated in the Norwegian Channel, and marine conditions were re‐established. The following Ristinge advance from the Baltic, initiated c. 55 kyr BP, also reached northern Denmark, where it probably merged with the NCIS. The deglaciation, c. 50 kyr BP, was followed by a long period of marine arctic conditions. Around 30 kyr BP, the Scandinavian Ice Sheet expanded from the north into the Norwegian Channel, where it dammed the Kattegat ice lake. Shortly after, c. 29 kyr BP, the Kattegat advance began, and once again the Scandinavian and British Ice Sheets merged in the North Sea. The subsequent retreat to the Norwegian Channel led to the formation of Ribjerg ice lake, which persisted from 27 to 23 kyr BP. The expansion of the last ice sheet started c. 23 kyr BP, when the main advance occurred from north–northeasterly directions into Denmark. An ice‐dammed lake was formed during deglaciation, while the NCIS was still active. During a re‐advance and subsequent retreat c. 19 kyr BP, a number of tunnel‐valley systems were formed in association with ice‐marginal positions. The NCIS finally began to break up in the Norwegian Sea 18.8 kyr BP, and the Younger Yoldia Sea inundated northern Denmark around 18 kyr BP. The extensive amount of new and existing data applied to this synthesis has provided a better understanding of the timing and dynamics of the Scandinavian Ice Sheet (SIS) during the last c. 160 kyr. Furthermore, our model contributes to the understanding of the timing of the occasional release of large quantities of meltwater from the southwestern part of the SIS that are likely to enter the North Atlantic and possibly affect the thermohaline circulation.  相似文献