摘要:

Different topics of Quaternary geology were dealt with at a symposium arranged in 1986 in Århus, Denmark: (1) reviews on recent Quaternary research in the Nordic countries, (2) studies of stratigraphy and geological processes in the Fennoscandian Border Zone, which demonstrate that the Quaternary deposition pattern is highly influenced by tectonic movements, and (3) Quaternary research as it can be applied to geotechnical investigations in the search for raw materials, in connection with pollution, and with conservation

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1987.tb00103.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Norwegian Quaternary research has experienced rapid development during recent decades, from a rather weak position before 1960 to a more ‘normal’ position in 1986. A brief comparison with the status in 1960 is attempted, in order to understand this development and the present day sta

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1987.tb00104.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The author gives a brief review of the most important research on Quaternary geology in Sweden during the last few years and the main lines of development of ideas. Emphasis is put on the present ‘state of the art’ within the following fields: Mapping, international projects, Quaternary deposits, dating methods, Pleistocene stratigraphy, glaciation models, deglaciation, sea‐level changes, and Hol

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1987.tb00105.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

A 120 m thick marine Quaternary sequence resting on Upper Cretaceous chalk at Nørre Lyngby has been stratigraphically analysed on the basis of its foraminiferal content. The foraminiferal zones in the Nørre Lyngby boring are compared with corresponding zones from borings and outcrops in adjacent areas in Vendsyssel and Kattegat, and a general zonation covering the whole area is proposed. The lower part of the marine sequence at Nørre Lyngby represents deposits of pre‐Eemian, possibly Saalian, and Eemian age. The Early Weichselian seems to be missing, while most of the Middle and Late Weichselian foraminiferal zones known from Vendsyssel occur. The foraminiferal zones and the corresponding macrofossil zones are correlated with the oxygen isotope stratigraphy. A cross‐section through deposits from the Saalian‐Eemian‐Weichselian marine basin in North Jutland and the Kattegat illustrates the development of the basin through this period of time. The centre of basin subsidence shifted from the southwest in the pre‐Eemian to the northeast in the Eemian, and remained there throughout the

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1987.tb00106.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Widely scattered marine Elsterian and Holsteinian deposits around the Limfjord and in the Kattegat region have normally subsequently been displaced by ice. The stratigraphic position and palaeoenvironments of these are discussed on the basis of their foraminiferal faunas and a few absolute dates. The concentration of finds around the present Limfjord might indicate the presence of a fjord system extending from the North Sea across to the Kattegat during the Late Elsterian–Holsteinian. The exact position of this coastline in the Kattegat region is still difficult to establis

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1987.tb00107.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Refraction seismic measurements from Kattegat have been analysed for information about Quaternary deposits. Preliminary results show a gradual increase in thickness of the Quaternary deposits from about 50m in the SW to 150–250m in the NE, close to the Swedish coast. A number of narrow zones with extraordinarily great thickness are superimposed on this surface. Comparisons with structural features in the pre‐Quaternary, as known from reflection seismic investigations, strongly indicate that the ‘Kattegat Basin’ is a structural phenomenon generated by subsidence under tensional stress perpendicular to the Fennoscandian border zone. Stratigraphical analysis which is available from wells on the islands in Kattegat and in Vendsyssel shows that subsidence of the ‘Kattegat Basin’ was initiated in Holstein

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1987.tb00108.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Magnetostratigraphical results from various historical, Holocene, Lateglacial and Glacial deposits from Central Jutland, Vendsyssel, the Baltic Sea and Schleswig‐Holstein are illustrated and discussed. Although only a few archaeomagnetic case studies have yet been made in Denmark, magnetic datings with accuracies of about ±50 years have been obtained on mediaeval kilns by comparing with a dipole transformed modification of the British archaeomagnetic master curve. Furthermore, a study of the expected east–west orientation of some 330 Romanesque churches in Denmark seem to indicate that about 25% of these churches were magnetically orientated; thus some kind of a magnetic compass may have been in common use in the twelfth century in Denmark. Radiocarbon‐dated Holocene lake sediments from lake Skanderborg reveal a distinct pattern of magnetic secular variation with fairly short time constants, which may be useful in magnetostratigraphical correlations of other lake sediments. Also Lateglacial and Early Postglacial sediments from the southern Baltic Sea show systematical magnetic patterns, whereas glacial boulder clay at the bottom shows disturbed directions, obviously moulded by the moving ice. Lateglacial Younger Yoldia clay from North Jutland shows well‐developed short periodic swings as well as an extreme declination variation of some 80° to 90°, the so‐called ‘Nørre Lyngby declination excursion’ around 14,000 B.P. A sequence of Older Yoldia clay at the same site furthermore shows significantly low inclination values, the so‐called ‘Rubjerg low inclination excursion’ of an age between 23,000 B.P. and 40,000 B.P. Finally, a well‐clustering palaeomagnetic direction from a Weichselian glacial boulder clay from Timmerhorn north of Hamburg is discussed from a hierarchical,

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1987.tb00109.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Relict spits shown on the first contour maps of Northern Jylland indicate that in postglacial times there were several straits linking Limfjorden to the North Sea across what is now a single island. At least two generations of spits can be seen on the uplifted marine plain. The spits at the higher elevation were formed by forces coming from northerly directions, while the lower spits were subjected to forces coming only from Limfjorden.

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1987.tb00110.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Since 1979 the Laboratory of Geophysics, University of Aarhus, has been developing a new prospecting tool for obtaining information on the topmost 100 m of the earth. The method is an extension of the conventional geoelectric sounding method, but instead of direct current (DC) the AC‐geoelectrical sounding method uses alternating current (AC) with frequencies in the range 100 Hz to 20,000 Hz. The use of alternating current adds an inductive contribution to the ordinary galvanic electric field, thus producing two different sorts of information about the underlying earth structure. These two sets of information are, in many cases, of complementary nature, which enables determination of the ground parameters much more accurately than would otherwise be possible from ordinary DC‐geoelectrical soundings. Among these cases is the high resistivity equivalence which appears so frequently in Danish Quaternary depos

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1987.tb00111.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

During a search for unpolluted resources, new wells have been drilled to a deep confined aquifer in central Jutland. Since little is known about the extent and vulnerability of the deep reservoir, geophysical logging was used to supplement hydraulic well‐testing. Gamma‐ray, SP and resistivity logs were recorded in the boreholes. Gamma‐logs were also recorded in two cased wells. Analysis of the logs, combined with information from samples, shows an unconfined aquifer of quartz and mica sand to a depth of about 55 m at Grindsted. Below this level there is a 40 m thick aquitard with an apparent southerly dip. The aquitard is composed of interbedded sand, silt and clay. The deep confined aquifer extends from 95 to 110 m below the surface at Grindsted. Both the aquitard and the deep aquifer are provisionally dated as Early/Middle Miocene. The electrical logs discriminate well between sand, silt and clay beds. If a suitable mud is used in the well it is possible to calculate the formation water resistivities in good agreement with water samples obtained after completion. From the resistivity logs formation factors were calculated in the range 3–5 using no‐invasion departure curves. The high content of heavy mineralsin the Tertiary deposits makes it impossible to obtain precise lithological information from the gamma‐ray log. On the other hand this log provides clear markers for identifying the hydrogeological units in the

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1987.tb00112.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY