摘要:

AbstractDeer species provide a valuable biostratigraphical tool through Cromer Forest‐bed times, due particularly to species turnover between the Early and early Middle Pleistocene. This study is based on the reidentification of 348 fossil antlers. The provenance of most large mammal fossils from the CF‐bF, collected over 150 years, was recorded only by the nearest coastal village. None the less, analysis of the cervid taxa by these ‘localities’ reveals interesting patterns. The fauna of the West Runton Freshwater Bed is of early Middle Pleistocene complexion, and that from the foreshore at East Runton is of Early Pleistocene. Pure or nearly pure early Middle Pleistocene assemblages also occur at Kessingland‐Pakefield and at Trimingham. At Overstrand, Sidestrand, Mundesley, Bacton and Happisburgh, there is a mixture of Early and early Middle Pleistocene elements. Analysis of Savin's data shows that fossils of earlier species were generally found further down the beach than those of later ones. Late nineteenth century geological surveys, made when bone collecting was at its peak, give additional information about fossil horizons, which in several cases can be related to modern stratigraphical units. Most Early Pleistocene large‐mammal bones came from Pastonian conglomerates, in contrast to small‐mammal and molluscan assemblages mostly extracted from Pre‐Pastonian Crag. However, the diversity of Early Pleistocene CF‐bF cervid species in comparison with continental faunas, and their pattern of distribution between sites, suggests they may span more than one chronostratigraphic stage. Early Middle Pleistocene assemblages came from strata now referred to the Cromerian, and the differing proportions of taxa between sites provide limited evidence of t

ISSN:0267-8179    

DOI:10.1002/jqs.3390080202

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractAn assemblage of land snails from an aeolianite deposit on the coast of the southern Greek island of Andikithira is shown to date to 16 000 yr BP and thus represents the period of the last glacial maximum (LGM; Oxygen Isotope Stage 2). The assemblage has no modern analogue. Five of the ten species are extinct on the island and some of these now live only at high elevations (>950 m). Significantly cooler temperatures, some 5‐8°C below present, and slightly drier moisture conditions (lower rainfall, partially offset by reduced evapotranspiration at the lower temperature) are inferred. The large temperature depression at the LGM, well documented in northern and central Europe, extended also to the Mediterranean climate of southern Europe. Late Quaternary climatic changes had a considerable impact on the fauna of this isolated isla

ISSN:0267-8179    

DOI:10.1002/jqs.3390080203

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractThermoluminescence dating of potassium feldspar coarse grains from the fossiliferous Holsteinian marine formation of Herzeele, at the southern limit of the North Sea Basin, yields a minimum age of 228 £ 30 ka. A tentative correction for the long‐term fading of the TL signal in potassium feldspar is proposed, assuming a lifetime (τ) of 711 ka. This correction would yield a preliminary age estimate of 271 £ 36 ka. These results support a minimum Oxygen Isotope Stage 7 age, but do not preclude, at this stage of our research, a possible correlation with late Oxygen Isotope Stage 9. These results are in agreement, within the error of the method, with independent absolute dates (U‐Th and ESR) obtained onin situmarine shells, which range from 225 ka to 348 ka. This study provides evidence of the reliability of TL age estimates on potassium feldspar coarse grains from shallow‐marine sediments older than the Last Inte

ISSN:0267-8179    

DOI:10.1002/jqs.3390080204

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractIn Ostrobothnia, western Finland, buried fossil soils have been recognised in a number of places in the sandy sediments that occur between glaciofluvial deposits and overlying till. Samples from the soil horizons as well as below and above them were taken for optically stimulated luminescence (OSL) dating. The same sites were also sampled for thermoluminescence (TL) dating. Altogether five TL dates and seventeen OSL dates were obtained. The OSL dates can be grouped into two age classes, (i) 120‐163 ka and (ii) 76‐106 ka, whereas all TL dates are of the order 135‐155 ka. A comparison between the results obtained from the two dating methods shows that OSL dates are generally younger than the TL dates for the same sample. The discrepancy may arise partly from problems of setting a correct residual level in TL dating. If this is the case then the TL dates may indicate an upper limit for the true age. The results support the geological interpretation that the fossil soils were formed during the last interglacial, that the soil‐forming processes possibly also continued during the first Early Weichselian stadial and interstadial (Brørupsensu lato), and that in general the till‐covered glaciofluvial sequences, interpreted as eskers in Ostrobothnia, were deposited during the Saalian or Early Weichselian de

ISSN:0267-8179    

DOI:10.1002/jqs.3390080205

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractWhen viewed from the air, Scottish ‘hummocky moraine’ can be resolved into a series of linear ridges that resemble those found at the margins of actively retreating glaciers today. Recent work has supported the interpretation of these linear ridges as ice‐marginal landforms and the authors believe that the majority of ‘hummocky moraine’ deposits can be interpreted in this way. Consequently the pattern of deglaciation can be established fairly precisely from the pattern of linear ridges. This approach is applied to the landforms of the northern part of the Loch Lomond Stadial ice‐field in order to reconstruct the regional pattern of deglaciation. This leads to important inferences about the significance of topographic control during deglaciation and more importantly it provides fresh insight into the environment of the British Isles during the Loch Lom

ISSN:0267-8179    

DOI:10.1002/jqs.3390080206

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractA peat bed found under solifluction deposits on Godøya island, western Norway, accumulated during a few decades around 11 000 yr BP, at the end of the Allerød period of the Late Weichselian. Palaeoecological investigations showed a local vegetation succession on wet sand culminating in a mire community dominated byCarex nigra. Periodic flooding brought in sand and silt, which decreased as drainage was impeded sufficiently for standing water to develop. The surrounding terrestrial vegetation was dominated bySalixscrub, with some open heath and alpine habitats nearby. Apart from two aquatic species, the 29 insect taxa recorded are characteristic of alpine heaths, plant litter (underSalixscrub) and stream‐sides. Their remains, together with the terrestrial plant macrofossils, were washed into the mire from nearby.Because the fossils are locally derived, the environmental reconstructions are of the actual conditions at Godøy at ca. 11 000 yr BP. Palaeotemperature estimates from beetles and plants are in agreement. The coleopteran estimates (Mutual Climatic Range Method) suggest mean July temperatures of 10–13°C, slightly cooler than today (13.5°), and January temperatures between +1 and −10°C, similar to or much colder than today. Summer temperature estimates from individual plant taxa indicate that temperatures during the Allerød period were similar to today's, but estimates from the reconstructed vegetation and timber‐line positions give estimates up to 3.5° cooler. Temperatures fell 2.5–7.5°C at the Younger Dryas. This abrupt and severe cooling initiated the solifluction processes on Godøya that buried the peat.The Godøy peat bed and its contained fossils provide a rare glimpse of Allerød biota and environments at t

ISSN:0267-8179    

DOI:10.1002/jqs.3390080207

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractSix new radiocarbon ages and a pollen sequence are provided for Laguna Stibnite, a small lake on the Taitao Peninsula, Chile (latitude 46°25'S, longitude 74°24'W). The sediments record a late‐glacial to present sequence, with a basal age of 14 335 ± 145 yr BP (Q‐2840). The radiocarbon ages provide the basis for a sound chronology in a region of Chile where few palynological studies have been made and where previous radiocarbon ages are ambiguous. The chronology from Laguna Stibnite supports the acceptance of a radiocarbon chronology based on wood fragments (rather than bulk analysis) at a site near Puerto Edén further south in the Chilean Channels (49°08'S). These data from Laguna Stibnite provide evidence for an early deglaciation (before 14 000 yr BP) in this region of southern Chile. The sequence provides no evidence for a climatic reversal between 11 000 yr BP and 10 000 yr BP, the so‐called Younger D

ISSN:0267-8179    

DOI:10.1002/jqs.3390080208

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

摘要:

AbstractQuaternary glacial diamictons in section R47, overlying Ordovician shale in the Rouge River Basin of south‐central Ontario, are considered to be representative of older and younger Wisconsinan glacial diamictons in the field area. Field characteristics, clast composition, mineralogy, particle size and geochemistry permit delineation of two units within the sequence and subdivision of deposits that correlate with Sunnybrook and Halton diamictons of Wisconsinan age. No Wisconsinan interstadial deposits are present in the section; however, outwash sandy gravel capping the Halton diamicton was probably emplaced by a high‐energy stream draining into Lake Iroquois just prior to the incision of the Rouge Valley in the later Wisconsinan (ca. 11 000‐12 000 yr BP). A buried palaeosol, which developed in this sandy gravel and in overlying aeolian sediment, shows partial leaching of carbonates and a slight increase of clay in the palaeosol solum. The main clay‐mineral transformations in the buried palaeosol appear to involve the degradation of illite and illite‐smectite accompanied by the production of vermiculite and minor amounts of chlorite. The ground soil capping the buried palaeosol is formed in colluvium emplaced 200 ± 80 yr BP following a local forest fire; the ground soil Ahk horizon gives an age of 4000 yr in the future, probably as a result of nuclear bomb testing effects on modern radiocarbon. The presence of an A/C profile in the ground soil system, although thin, indicates that surface soils may form rapidly.The geochemistry of the two Wisconsinan diamictons shows similar calcite and SiO2‐corrected mean element concentrations, with slightly elevated levels of Ca, Sr, Hf and Lu in the younger deposit. Both diamictons are geochemically quite different from the shale bedrock in the area, indicating that the bulk of transported sediment came from outs

ISSN:0267-8179    

DOI:10.1002/jqs.3390080209

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0267-8179    

DOI:10.1002/jqs.3390080211

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY

ISSN:0267-8179    

DOI:10.1002/jqs.3390080212

出版商:John Wiley&Sons, Ltd    

年代:1993

数据来源: WILEY