Middle Pleistocene Sequences Research Articles

The Middle and Upper Pleistocene sequence in the Lower Thames: a record of Milankovitch climatic fluctuation and early human occupation of southern Britain: Henry Stopes Memorial Lecture 2004

The sequence of Pleistocene river terraces in the Lower Thames, long recognized as an important repository of evidence for Palaeolithic human activity, can now be interpreted in the context of the last five Milankovitch (100 ka) climate cycles, beginning with cold marine oxygen isotope stage (MIS) 12, when ice sheets blocked an earlier Thames course in Hertfordshire and Essex. This interpretation stems from empirical evidence from the Lower Thames deposits, in which the preservation of faunal and archaeological remains is unusually common. These deposits were laid down as climatically generated river terraces, formed in synchrony with the climatic cycles, although the progressive incision to ever-lower valley-floor levels is a response to background uplift. Interpretation of this evidence is revised here for the Dartford-Purfleet area in recognition of a phase of minor downcutting at the ends of interglacials. Previously regarded as insignificant, it is now realized that this erosion phase has resulted in interglacial sediments forming the higher of two facets within each terrace in the Lower Thames. Guided by this revision, the Lower Thames (Thames-Medway) terrace sequence further downstream, in eastern Essex, is reappraised in the light of the better preserved and better understood record from the Dartford-Purfleet area. It is concluded that Thames-Medway drainage northwards to the Clacton area (NE Essex) persisted until after the Hoxnian (MIS 11), so that the Clactonian (Palaeolithic) type locality lay in the main Thames valley at the time when the Clactonian knappers were operating. Despite its relegation in recent years from the earliest British Palaeolithic culture to little more than a curious anomaly, with doubts expressed about its separate existence, recent interpretations of the Clactonian hold that it appeared within the Thames sequence on two separate occasions, both coincident with a glacial to interglacial transition. These separate Clactonian occupations, at the MIS 12-11 and 10-9 transitions, together with the first appearance of the Levallois technique at around the MIS 9-8 boundary, can be linked to the chronology and to the cyclic climatic record that together underpin the Lower Thames sequence.

A perspective on D. R. Bridgland's paper ‘The Middle and Upper Pleistocene sequence in the Lower Thames: a record of Milankovitch climatic fluctuation and early human occupation of southern Britain’

A perspective on D. R. Bridgland's paper ‘The Middle and Upper Pleistocene sequence in the Lower Thames: a record of Milankovitch climatic fluctuation and early human occupation of southern Britain’

Age of Middle Pleistocene fauna and Lower Palaeolithic industries from Kent's Cavern, Devon

Kent's Cavern has long been known as potentially among the oldest Palaeolithic sites in the country, with the basal Breccia deposit containing a sparse Lower Palaeolithic industry. The sediment consists of a chaotic clayey conglomerate emplaced as a series of debris flows, which entered the cave via blocked entrances at its southwest end. The Breccia contains a fauna dominated by the bear Ursus deningeri, with lion Felis leo and the voles Arvicola cantiana and Microtus oeconomus, establishing a late Cromerian age for the deposit. The artefacts comprise an industry of crudely manufactured handaxes and flakes, and show damage suggesting that they were brought into the cave by the debris flows, and may thus predate the sediment and fauna. We demonstrate an age of >340 ka for the Breccia using two independant dating methods, consistent with existing models of the age of the British Middle Pleistocene sequence.

Biostratigraphical correlation between the late Quaternary sequence of the Thames and key fluvial localities in central Germany

The shared characteristics of limestone bedrock geology and resultant calcareous groundwater have allowed excellent preservation of mammalian and molluscan faunas within the terrace sequences of the Lower Thames and the rivers of the Muschelkalk region of Thuringia, central Germany. The mammalian and molluscan assemblages from the Lower Thames have underpinned the dating of one of the most important late Middle Pleistocene sequences in Britain and probably also Europe; one that is the repository of a highly significant Lower and Middle Palaeolithic archive. The most complete terrace records in Thuringia are those from the River Wipper, in the region of Bilzingsleben, and the Ilm, around Weimar. Both here and in the Lower Thames, interglacial deposits representing the four major post-Elsterian temperate-climate complexes (=oxygen isotope stages (OIS) 11, 9, 7 and 5 of the oceanic record) have been identified. In the Thames the interglacials are represented by fluvially deposited sediments, whereas in Thuringia they are frequently represented by travertines that formed around calcareous springs, often containing exquisitely preserved fossils. Evidence from Lower Thames interglacial deposits within four different terrace formations (Boyn Hill/Orsett Heath, Lynch Hill/Corbets Tey, Taplow/Mucking and Kempton Park/East Tilbury Marshes) is reviewed, in addition to which new evidence from a site at Hackney Downs, East London, is summarized. The deposits at the last-mentioned site are part of the Lynch Hill/Corbets Tey Formation and include interglacial sediments attributed to OIS 9. As well as the record of travertine complexes from each terrace level within the Bilzingsleben staircase, the celebrated travertine sequence at Weimar-Ehringsdorf, on Terrace 4 of the Ilm, is described. The biostratigraphical and palaeoenvironmental evidence from the Ehringsdorf travertines compares closely with that from interglacial deposits at Aveley, in the Mucking Formation of Lower Thames; both are attributed to OIS 7, with comparison possible at the oxygen isotope substage level.

Middle pleistocene pollen biostratigraphy in the central north sea

Middle Pleistocene sequences from the northernmost (Fladen Ground) and the southernmost (Devil’s Hole area) parts of the British sector of the central North Sea are correlated on the basis of pollen biostratigraphy. Four pollen stratigraphies are compared, with reference taken to existing borehole and seismic data. The most pronounced influence of reworked pre-Quaternary sediments are present in an upper interval, rich in pre-Neogene palynomorphs, and in a lower interval, rich in Neogene palynomorphs. This change can be related to Middle Pleistocene glacial periods. The pollen content in the younger interval indicates a British provenance, possibly correlated with the Saalian stage. The pollen content in the older interval indicates derivation from the Scandinavian ice sheet, and may correlate with the Elsterian stage. The pollen stratigraphies between these two intervals reflect a vegetational transition from dwarf shrub heaths and peatlands towards boreal forests, possibly followed by a return to a more open landscape. This pollen stratigraphical succession is best preserved in the Devil’s Hole sequences. In the Fladen Ground the upper part of the sequence may have been glacially eroded. Deposits of Cromerian Complex age occur at base of the Middle Pleistocene sequences.

Pleistocene pollen stratigraphy from borehole 81/34, devil’s hole area, central north sea

Twelve pollen assemblage zones are identified in a 229 m deep borehole (BH 81/34) from the Devil’s Hole area in the central North Sea (British sector). The sediment from this borehole is Early to Late Pleistocene in age and the observation of massulae from Azolla filiculoides in sediment with reversed polarity indicates an age younger than the Olduvai geomagnetic event for the entire sequence. The Early Pleistocene sediments were at least partly deposited in the vicinity of a river outlet and can be correlated either with the Eburonian or the Menapian cold stage and with the Bavel interglacial and the Linge glacial within the Bavelian stage in the Dutch stratigraphy. The Middle Pleistocene sequence contains an interval rich in Abies, Picea and Pinus, probably deposited during the end of either Cromerian Complex interglacial IV (Noordbergum) or possibly the Holsteinian. The uppermost 80 m of the core contains high frequencies of pre-Quaternary and deteriorated palynomorphs indicating extensive glacial or glaciofluvially reworked sediment.

Early and Middle Pleistocene pollen stratigraphy from British geological survey borehole 81/29, Devils Hole area, central North Sea

The palynomorph content is described of Early and Middle Pleistocene sediments from a 140 m deep borehole (81/29) from the Devils Hole area, central North Sea. The Early Pleistocene sequence in 81/29 is interpreted as predominantly of Bavelian age and is correlated with an existing Fladen Ground stratigraphy; it also supports a previous foraminiferal correlation. The overlying Middle Pleistocene sequence contains a climatic amelioration of interstadial or interglacial status. Pollen assemblages from Saalian sediments in the uppermost part of the core indicate that the site of 81/29 received a strong influx of reworked material of British origin.

Small mammal taphonomy of Gran Dolina, Atapuerca (Burgos), Spain

Abstract The middle Pleistocene sequence at the Atapuerca (Burgos) complex of caves is most completely represented at Gran Dolina. Eleven stratigraphic units are distinguished, seven of which contain abundant small mammal fossils. These seven units are analysed in order to determine the taphonomic processes present during the accumulation of their faunal remains. The fossil bones are extensively broken, both before and after burial. Fossils from six of the units show evidence of localized pre-depositional acid corrosion, which occurred both before and after breakage. In the upper levels, there is also evidence of post-depositional corrosion, both from alkaline and from acid environments of deposition, and in the top level some fossil bones also show evidence of weathering and root marks. Images of these modifications, by means of the scanning electron microscope, and their comparison with a large comparative data base of recent modifications from known causal agents, permits the identification of the agents responsible for many of the modifications, and consequently the reconstruction of the sequence of events leading to the accumulation and preservation of the fossil assemblages. Predators are implicated for some of the breakage and all of the pre-depositional corrosion, which is the result of digestion in the predators' stomachs. In all cases the category of predator can be identified, and at three stratigraphic levels the actual species can be identified with moderate degrees of reliability. Post-depositional corrosion is linked with observations on local acidity/alkalinity of different levels, and the incidence of weathering is linked with evidence for roof collapse over parts of the cave. Taking account of the effects of these processes, particularly the selectivity resulting from predator hunting methods, allows estimates to be made of the degree of bias in the faunal composition and the palaeoecology thereby indicated.

The Quaternary succession in the northern North Sea

Studies of core material show that the upper 200 m of sediments deposited in central parts of the North Sea span the last ca. 1 Ma. In the Norwegian Trench, the upper 120 m span the last ca. 500 ka. Sedimentation in both areas was characterized by rapid rates over short intervals separated by long hiatuses. In the central area, fine-grained shallow-water sediments dominate the Pleistocene sequence. These sediments were redeposited/transported by rivers flowing northward from the British Isles and the continent during periods of low sea level through the Quaternary. The extreme low stands of sea level are also indicated by river channels cut in the sequence in the northern North Sea. In the Norwegian Trench, thick glacial and glacial marine diamictons make up ca. 80% of the record in the Middle and Late Pleistocene sequence. The northern North Sea was glaciated as early as 850 ka. Evidence of possibly the most extensive glaciation of the North Sea Basin has been dated to between 200 and 450 ka in cores from The Fladen area. The British and Scandinavian Ice Sheets probably did not coalesce in the North Sea during the late Weichselian maximum.

Evidence of Middle Pleistocene marine transgressions along the Mediterranean Coast

Typical Middle Pleistocene sequences outcropping along French and Italian coasts are described. Age determination from palaeolithic industries and absolute dating methods correspond to oxygen isotope stages 9 and 11. Evidence of the same transgressive cycles are also indicated in other Mediterranean districts.

Tephrochronological study on the middle Pleistocene deposits in the Kanto and Kinki districts, Japan

The middle Pleistocene time range is defined here the period before the last interglacial in the Brunhes epoch. In Japan, the Shimosa-Kazusa Groups around the Tokyo Bay in Kanto and the upper part of the Osaka Group in Kinki both represent the standard middle Pleistocene sequences and have been studied in detail. These groups are characterized by the cyclic sedimentation caused by transgression and regression corresponding to climatic changes.The purpose of this paper is to attempt the correlation of the Kazusa Group and the Osaka Group by identification of widespread marker-tephras. Accurate determinations of the refractive indices of volcanic glass, orthopyroxene and hornblende, together with other determinations, have enabled successful characterization for correlation to be made for several tephra layers in southern Kanto and Kinki. The following marker-tephras are found over two districts, resulting in the establishment of several important datum planes in the middle Pleistocene sequences.The vitric tephra called Ks 11, which is sandwiched in the Kasamori Formation and its correlatives in southern Kanto, can be identified as a marker tephra of the Osaka Group called Sakura ash, in the vicinity of Osaka and Kyoto. The estimated age of this tephra, about 450, 000 years, is based on its stratigraphic relationship with the underlying dated tephra, Kinukawa ash (460, 000-470, 000 years). Stratigraphically, it is included in the deposits immediately below the transgressive horizon (Tama-f and Ma 7) and also occurrs in the biozone of Stegodon orientalis in both districts. The vitric tephra called Ku 1, sandwiched in the Kokumoto Formation, is identified and correlated with a tephra called Imakuma I ash. It is included in the deposits immediately above the Brunhes-Matuyama boundary. The very important dated tephra, Azuki ash (870, 000 years), in the Osaka Group, can be correlated with Ku 6C tephra in the lower part of the Kokumoto Formation by their peculiar petrographic properties. Both are sandwiched in the deposits below the Brunhes-Matuyama boundary.From the relationship between the identified tephras and marine sequences, it is concluded that during the period from 700, 000 years to 450, 000 years at least three interglacial-glacial cycles are recorded, and that after 450, 000 years the following major interglacial episodes are indicated; 450, 000YBP, 370, 000YBP, 300, 000YBP, 230, 000YBP, and 130, 000YBP.

Fission-track ages and correlation of middle and lower pleistocene sequences from Nebraska and New Zealand

Abstract Fission-track dates of glass shards from volcanic ash in two rhyolitic pumice beds that are separated by 975 m of Castlecliffian (middle Pleistocene) marine sediments from south-western North Island, New Zealand, indicate that the Castlecliffian Stage began about 1•19 ± 0•14 m.y. ago and ended slightly less than 0•39 ± 0•01 m.y. ago. Correlation of the New Zealand marine sequence with the glacial sequence of eastern Nebraska by fission-track dates indicates that the Nukumaruan/Castlecliffian boundary (early middle Pleistocene) is equivalent to the Nebraskan Aftonian/Kansan boundary at about 1•2 m.y. The Castlecliffian Stage appears to have a time span equivalent to the entire Kansan and Yarmouthian Stages and probably part of the Illinoian Stage of eastern Nebraska. The beginning of the New Zealand Nukumaruan Stage may coincide with the beginning of the Nebraskan Stage, dated at about 2•0 m.y., and these two stages may be of similar duration. The two New Zealand dates show that 975 m of Castlecli...