摘要:

The results from a Nordic research project on Quaternary geology, entitled theNordkalottproject, were presented at a symposium in northern Sweden in 1987. Organic deposits and tills in northern Fennoscandia are interpreted as belonging to the Eemian as well as to interstadials and stades of the Weichselian. Retreat of the ice front under cold climatic conditions has been assumed for parts of northern Norway. Ice‐dammed lakes formed during the deglaciation period are described from northern Finland.Boreas, Vol. 17, no. 4, consists of articles based on the symposium contribution

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1988.tb00559.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The Quaternary geology of the Nordkalott area in northern Fennoscandia is depicted in five maps. The themes of the maps are: Quaternary deposits, glacial geomorphology and paleohydrography, ice‐flow indicators, Quaternary stratigraphy and ice‐flow directions. The maps are briefly presented and an outline of the glacial history of the Nordkalott area is gi

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1988.tb00560.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

An active search for pre‐Holocene organic deposits in stratigraphically well‐defined positions has proved to be a useful tool for reconstruction of glacial and non‐glacial Weichselian development in northernmost Sweden. The investigations have been concentrated to kettle holes connected to eskers belonging to a morphologically prominent northwesterly glacial system characterized by extensive drumlinization. Organic deposits, radiocarbon‐dated as older than the Holocene, have been found at some 25 localities. Some sites display two organic‐bearing sequences separated by a till bed. The pollen flora in the lowest organic bed reflects an interstadial vegetational development: Arctic shrub and herb tundra‐subarctic light birch forestherb tundra with ericaceous shrubs and dwarf birch. This interstadial is correlated with Peräpohjola in Finland. During the younger Tärendö Interstadial the vegetational development was similar, but a more continental climate is indicated hy high values of steppe plants, e.g.Artemisiaand Chenopodiaceae. The Tärendö Interstadial, correlated with Odderade, wascharacterized by open, unstable soils due to periglacial processes such as cryoturbation and eolian activities. The Weichselian glaciation is divided into three glacial stades separated by ice‐free interstadials in the area studied. Except for a zone with S‐SW drumlinization the impact of the two later ice she

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1988.tb00561.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

The Veikimoraines in northernmost Sweden display a very conspicuous distribution pattern, sharply demarcated to the east and successively decreasing to the south, west and north. The sharp demarcation to the east is thought to reflect the front of a stagnant ice sheet. The downwasting of this glacier was retarded by the insulation of a thick superglacial debris cover and subarctic vegetation invaded at least parts of the slowly collapsing ice. Radiocarbon datings of organic matter deposited in connection with the formation of the Veiki moraine, lithostratigraphical evidence and the relation to other glacial features prove the Veiki moraine landscape to date from the deg laciation of the first Weichselian ice sheet, i.e. the Peräpohjola Interstadial. The good preservation of the features implies that in extensive areas of northern sweden the Early Weichselian glacial landscape escaped significant erosion despite being overrun by two later glaciers. Previous interpretations of the Late Weichselian/Holocene deglaciation are largely based on an Early Weichselian deglaciation pattern

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1988.tb00562.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Frost‐shattered bedrock and ventifacts interpreted to be abraded by drifting snow or ice particles occur frequently in the wooded areas of northernmost Sweden. Ice‐wedge casts and periglacial involutions are encountered more sporadically. The phenomena cannot be explained by the present or the Holocene climate and demonstrably pre‐date the last deglaciation. The relation to glacial and non‐glacial stratigraphy, and to ice flow during the latest glacial stade, strongly suggests that the periglacial activity dates from the local Tärendö Interstadial, tentatively correlated with Odderade. The presence of the periglacial features implies not only that different morphological formations survived the erosive impact of the last continental ice sheet but also that in wide areas the very ground surface, including ventifacts in primary position, is the same today as during the interstadial. A similar situation appears to prevail in northernmost Dalecarlia and parts of Härjedalen and Jämtland in cen

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1988.tb00563.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

A peat layer beneath two till beds was found at Seitevare in Swedish Lapland. The pollen flora layer indicates deposition during the later part of the Eemian Interglacial. The vegetation consisted of open forests predominated by pine and birch, mixed with alder and spruce. The sedimentation took place in a small oligotrophic‐dystrophic water basin with a pH about 5, according to the diatom flora. In an adjacent section, silty sediments with pollen indicating interstadial vegetation (birches, herbs) are covered by one till bed. These sediments are tentatively correlated with the Peräpohjola Interstadial in northern Finland and north‐eastern Sweden. The lithostratigraphy indicates one pre‐Eemian and probably three Weichselian glacial ad

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1988.tb00564.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

At four localities in area east of the Sarek and Kebnekajse massifs in Swedish Lapland, glaciofluvial channels seem to have been overhidden by glaciers without having extensively modified. It is suggested that the channels were formed during an Early Weichselian stade. The last glaical advance had little effect on the pre‐exiting landforms at these localities and probably also at many other places in the area. Earlier theories about glacial development and deglaciation patterns in this area are based on morphology and the assumption that the landforms were formed during the last deglaciation. These theories need to be revise

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1988.tb00565.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Till beds and waterlain sediments from at least 3 stadials and 2 interstadials during the Weichsel glaciation are recorded on Finnmarksvidda. The oldest, possibly Weichselian, ice‐free period recorded on Finnmarksvidda is represented in one river section and is preliminary named theVuolgamasjåkka thermomer.Its initiation is TL‐dated to about 120 ka, which indicates a pre‐Weichselian, possibly Eemian age. The interstadial which follows the subsequent and assumed oldest Weichsel stadial on Finnmarksvidda, the Eiravarri interstaeial, has previously been tentatively correlated lithostratigtrahically with the Peräpohojola interstadial (sensu stricto) in North Finland. The youngest interstadial, theSargejåk internatiodial, is in this paper suggested to correlate with the Tärändö interstadial in North Sweden. The initial Weichselian ice movement across Finnmarksvidda is so far unknown, but locally N of Kautokeino in the W the initial (recorded) ice movement was directed towards NW‐N. The regional ice movements for the two subsequent stadials on Finnmarksvidda were initially directed towards NE‐ene and NN

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1988.tb00566.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

Traces of ice‐dammed lakes are found along the southern part of the Saariselkä mountain range. Various shore marks, outlet channels and fine‐grained sediments are indications of open water. The shallow basins were more or less filled by dead ice. At the beginning of deglaciation the meltwaters discharged over the mountain ridge to the north. As the ice margin receded toward the southwest new outlets were opened and the meltwaters discharged to the east and southeast. The ice‐dammed lakes existed and the deglaciation took place during the period 9,500‐9,300 B.P. The annual rate of retreat of the ice margin averaged 130–170

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1988.tb00567.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY

摘要:

In the Finnmark region of northern Norway, end from Younger Drays and earlier periods appear as irregular mounds and ridges in a broad zone with a distinct distal margin. These moraines are similar in shape to end moraines formed in Svalbard today by melting of ice‐cored moraines in front of subpolar glaciers under permafrost conditions. The end moraines in Finnmark were mkost likely formed in the same way in a permafrost climate during deglaciation. This might also be the case for moraines in the southernmost parts of Fennoscandia, in Denmark and southernmost Sweden. Cold‐based ice during deglaciation in central parts of Fennoscandia is due to climatic conditions tens of thousands of years earlier. The period with climatic improvement after the Weicheselian maximum was too short to have any influence on the thermal conditions at the base of the ice‐cap in the central

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1988.tb00568.x

出版商:Blackwell Publishing Ltd    

年代:1988

数据来源: WILEY