摘要:

From a study of molluscan assemblages it is suggested that sea temperatures, particularly in the period 12,500 to 12,000 B.P., were 3°C lower than they are today for all but surface waters, implying that the interstadial North Atlantic Drift was weaker than the present Drift where it extends into the Norwegian Sea. An early interstadial ‘warm’ event may relate to a period when temperatures in the Bay of Biscay exceeded those of the present day. A later ‘warm’ episode may correlate with the warmest part of the interstadial deduced from the deep sea succession west of

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1983.tb00439.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Palaeobotanical investigations of limnic sediments in the Karlich clay pit (Middle Rhine area) in Northwestern Germany indicate that deposition took place during a middle Pleistocene interglacial, the initial part of which is absent at the site investigated. Of special biostratigraphic importance is the occurrence of taxaAzolla filiculoides, PterocaryaandCeltis auslralis.In theCarpinus‐Betulazone of this interglacial, early Palaeolithic artifacts are present. Remains of mammalian fauna have been found in the investigated layers. The interglacial has no clear palaeobotanic equivalent in Northwestern Europe, but the intermediate character of the palaeoflora suggests an intra‐Saalian

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1983.tb00440.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Hilda Glacier, a small cirque glacier in the Canadian Rocky Mountains, yields two principal types of sediment: ablation till, deficient in fine material and produced by rockfalls and avalanches falling on to the glacier surface, and basal lodgement till, rich in fines and formed mainly by subglacial erosion. Recent recession from its Neoglacial maximum has exposed large areas of basal till with thin veneers of ablation till which, when combined with present subglacial and supraglacial debris, provide abundant material for erosion and transport by the mcltwatcr stream. Sediment transport measurements over two summers (1977–1978) showed that bed load and suspended load occur in approximately equal proportions and that dissolved loads are minor. Local source variations, especially bank slumps, are a major cause of scatter in sediment rating curves. Suspended‐sediment concentrations are greater early in the melt season due to availability of loose sediment produced by freezing and thawing. Other contributors to scatter in suspended‐sediment rating curves include rain showers and diurnal hysteretic effects. Although the distinction between bed load and suspended load is never sharp, available data suggest that the sand/ gravel grain‐size boundary (‐1ø) approximates the suspendcd‐load/bed‐load division for characteristic Hilda flows transporting gravel. This approximation, combined with till grain‐size analyses, suspended‐sediment measurements, and spatial distributions of till types, leads to the following computations of fluvial sediment sources: for suspended load ‐ 6% supraglacial, 47% subglacial, 47% channel banks; for bed load ‐ 46% supraglacial, 27% each subglacial and channel banks. Supraglacial debris provides only about one‐fourth of all fluvial sediment, but nea

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1983.tb00441.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Isoleucine epimerization (alle/Ue) ratios in the pelecypodMya truncataand benthic foraminiferCibicides lobalulusfrom emerged marine units in western Norway allow construction of a regional relative chronostratigraphy for the Ecmian and Weichselian. Twoin situinterglacial sections are considered correlative by the similar biostratigraphy and alle/Ile ratios inC. lobalulus.Overlying sediments at the two sites are of both marine and glacial origin. Neither site contains a complete Weichselian record, but allelic ratios, lithostratigraphy and fauna! changes suggest at least four stadial and three interstadial events occurred along the western Norwegian coast during Early and Middle Weichselian time. Kinetic data defining the relationship between the isoleucine epimerization rate constant and temperature for the species studied allow the estimation of paleotemperatures for samples of known age. Accepting published age estimates for the Eemian interglacial beds, the average Weichselian temperature in western Norway is calculated to have been ca. 4°C below the average Holocene temperature, whereas the last interglacial was 1 to 2°C warmer that the Holocene. The limited temperature depression over this region during the Weichselian implies that coastal western Norway was ice‐covered only about 30% of this period, and that Atlantic water, although not necessarily in a warm surface current as today, entered the Norwegian Sea during much of marine isotope stage 5 and intermittently during stage 3. Interpolated amino acid ages date interstadial events at ca. 94 ka, 78 ka and 52 ka, B.P., whereas glacial events are dated ca. 103 ka and bracketed by limiting dates between 78 and 89 ka, between 52 and 63 ka and less than 36 ka

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1983.tb00442.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

A coloured geomorphological map at the approximate scale of 1:50,000 is presented for the Ablation Point massif area. The main gcomorphological features have been described, such as ice and snow cover, glacial landforms and deposits (and chronology), ice marginal lakes, melt pools, gelifluction landforms and patterned ground and valley‐slope landforms. The area is thought to be a good analogue for glacial‐age maritime northwest Eur

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1983.tb00443.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Normal and reverse faults, thrusts and shears with traceable lengths rarely over 0.35 m and throws of up to 0.014 m are locally developed within a series of bedded glacial meltwater deposits. They are believed to have originated during undrained loading of those deposits by an overlying flow till of late Devensian age. Local disturbance of beds by injection of fluid fine sands indicates past generation of high porcwater pressures.

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1983.tb00444.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY

摘要:

Core recovered from IGS Borehole 78/9 is described and suhsamples have been examined for geotechnical properties, palaeomagnelic events and microfauna content. It was hoped that this approach would provide a Quaternary stratigraphy for the area by assuming that significant geological events correlate with simultaneous changes in the lithology, gcotechnical properties, geomagnetic polarity and climatic regime. The magnetic reversals observed were linked to the existing palaeomagnelic time scale and stratigraphic ages assigned to the various units obtained on a ‘best fit’ to this time scale. The stratigraphic succession and geological history deduced for the borehole are compatible with other borehole and vibrocore data available from the a

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1983.tb00445.x

出版商:Blackwell Publishing Ltd    

年代:1983

数据来源: WILEY