摘要:

This investigation was designed to compare the environmental inferences that can be made from fossil Coleoptera with those that can be made from palynological data. In the Glanllynnau kettle hole, sedimentation began at 14,000 BP and continued until about 10,000 BP. The Coleoptera from these deposits show that during this period there was only one climatic oscillation and that this differed in both timing and intensity from oscillations inferred from palynological evidence. Thus, at about 13,000 BP, an intensely cold continental climate suddenly gave place to a period with summer temperatures at least as warm as those at the present day, but during this episode the landscape was entirely without trees. From 12,000 BP to about 10,000 BP there was a progressive deterioration in the temperature, and the period ofBetulaforest, broadly equivalent to the Allerød, is shown to have a less thermophilous fauna than that of the previous pollen Zone I. An attempt is made to explain this anomaly in terms of the differential rate of response of the plants and animals to rapid climatic changes

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1972.tb00146.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

General problems in determining and interpreting shell C14dates are discussed: calculation methods, factors influencing primary activity (apparent age), and determination of contamination. It is concluded that shell dates are reliable when handled carefully. Measurements on ten shells, collected between 1898 and 1923 on the Norwegian coast, gave apparent ages from 340±75 to 550±80 years, indicating that apparent age is not a significant problem in dating of Norwegian shell

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1972.tb00147.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

Evolution of the width‐to‐depth ratios through time is subjected to a power function. It is the direct result of an increase in the amount of fine particles in the suspended load fraction. The evolution from coarse to fine sediments accompanies a change from fluviatile to eolian sedimentation. This evolution occurs gradually, as may be inferred from the Douglas diagram of the grain‐size distributions. This gradual evolution is subjected to exponential laws in both fluviatile and eolian sedimentation systems. In conclusion, all the evolutional trends considered encompass the growing cold and dry conditions of the climate throughout the Late Pleistocene (Eemian and Weichse

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1972.tb00148.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY

摘要:

The bathymetric distribution of recent arenacous Foraminifera has been studied in samples from the bottom surface in the Bay of Biscay, from depths of between 560 and 4450 m. Comparison could be made with the results obtained by Saidova from the Pacific Ocean. These forms have been studied in late Quaternary cores from the same area. This microfauna is very abundant and characteristic of the late Holocene. Some species are of stratigraphic or climatic index value: the rapid decline ofSiphotextularia rolshausenicharacterizes the beginning of the late Holocene.Adercotryma glomeratanow lives at depths exceeding 3500 m, but at least up to the middle Würm it lived on the continental slope.Karreriellais represented only after the Würm II‐Würm III interstade.Eggerellais represented at least since the end of Riss and disappears during Würm III. Some genera may provide information on the foraminiferal invasion of the abyssal plain.Les foraminifères agglutinants récents sont étudiés dans divers échantillons prélevés à la surface du fond marin du Golfe de Gascogne, entre 560 et 4450 m de profondeur; ainsi peut‐on envisager la distribution bathymétrique de ces formes et comparer nos résultats avec ceux obtenus par Saidova dans l'Océan Pacifique. Une série de carottes prélevées dans la m eme région permet létude de ces foraminiféres agglutinants durant le Pleistocéne supérieur. Cette microfaune est trés abondante durant lépisode le plus récent de l'Holocéne qu'elle caractérise. Certaines formes peuvent aussi servir de repères stratigraphiques ou climatologiques:Siphotextularia rolshausenicaractérise, par sa disparition brutale, la partie la plus récente de l'Holocène.Adercotryma glomeratavit actuellement audelà de 3500 m, mais habitait la pente continentale au moins jusqu'au Würm moyen.Karreriellase manifeste seulement depuis l'interstade Würm II‐Würm III.Eggerella,présent depuis au moins le sommet du Riss, disparait durant le Würm III. Enfin, certains genres nous permettent d'aborder le problème

ISSN:0300-9483    

DOI:10.1111/j.1502-3885.1972.tb00149.x

出版商:Blackwell Publishing Ltd    

年代:1972

数据来源: WILEY