Variation and pattern in the responses of mammal faunas to Late Pleistocene climatic change in southeastern South Australia

We examined mammal occurrence and variability through the Late Pleistocene vertebrate fossil deposit of Grant Hall in Victoria Fossil Cave, Naracoorte, South Australia. To determine long‐term patterns of change, we compared the composition and relative abundance trends of the assemblage with a nearby Middle Pleistocene deposit in Cathedral Cave. Total species richness did not change through the Grant Hall sequence, dated from 93 ± 8 to 70 ± 5 ka. However, species relative abundances varied between ecologically divergent species, and in some cases between species that demonstrate similar environmental preferences. For some species this variation is comparable to that recorded in Cathedral Cave. Of those showing similar trends between the two deposits, the forest inhabitant, Pseudomys fumeus, recorded an 8.6% decline through Grant Hall, coincident with a 9.7% increase in the dry heath/mallee dweller Pseudomys apodemoides. These patterns indicate that climatic transition from relatively warm, moist to cooler, drier conditions impacted some species in similar ways through climatic cycles of the past. However, the majority of the fauna demonstrated complex responses that are individual and variable through time. Statistical tests of species trends from the Grant Hall assemblage caution that large fossil samples are required to validate patterns observed. Copyright © 2012 John Wiley & Sons, Ltd.     

Electron spin resonance dating of the fossil deposits in the Naracoorte Caves,South Australia

The caves near Naracoorte, South Australia, contain one of the richest and most diverse fossil faunal assemblages on the Australian continent. Three sites were selected for electron spin resonance (ESR) dating because clastic, fossiliferous sediments were sandwiched between speleothem layers. This allows independent age control by highly precise thermal ionization mass‐spectrometry (TIMS) U‐series dating. We find that all ESR results agree within the constraints given by the U‐series dates, and allow further refinement of the age of the fauna analysed, indicating that most of the fauna in the large Victoria Cave Fossil Chamber is twice as old as reported previously. Our dating results, spanning from 280 to 500 ka for the Fossil Chamber, Victoria Cave, to about 125 ka for the Grant Hall, Victoria Cave, and 170 to 280 ka for the Fossil Chamber, Cathedral Cave, indicate little change, if any, in the megafaunal assemblage from the early Middle to the early Late Pleistocene. This changed dramatically after the last interglacial, when a large proportion of the megafauna suddenly disappeared. Copyright © 2001 John Wiley & Sons, Ltd.     

Huanglong Cave: A Late Pleistocene human fossil site in Hubei Province,China

This contribution discusses recent paleoanthropological findings from Huanglong Cave, a Late Pleistocene human fossil site from Yunxi County, Hubei Province, China. Three excavations in the Huanglong Cave from 2004 to 2006 yielded seven human teeth, some stone and bone tools, possible burnt sediment and other evidence possibly related to hominin activities. Based on the presence of extinct faunas (20% of total taxa identified), the deposits dated to the Late Pleistocene. Electron spin resonance (ESR) and uranium-series (U-series) dating analyses on associated teeth and speleothems have resulted in divergent chronometric ages (ESR: 44–34 ka; U-series: 103–79 ka). Analysis indicates: (1) most of the morphological and metric features of the human teeth from Huanglong Cave fall within the range of variation of modern Chinese, but a few characters may still link them to more archaic hominins; (2) some activity-induced abrasion and other tooth use-marks were identified, including pronounced tooth chipping and interproximal grooves on the anterior teeth; (3) the sample of blackened deposit has a high carbon content (over 70%), experienced high temperatures, and likely was of cultural origin and not natural; (4) the mammal fossils represent the “Ailuropoda-Stegodon” faunal unit which lived in southern China throughout the Pleistocene. Synthesizing all of these findings, especially the human teeth that display modern human characteristics, Huanglong Cave will offer some new insights into various issues currently being debated in Late Pleistocene human evolutionary research.     

A late Pleistocene record of aeolian sedimentation in Blanche Cave, Naracoorte, South Australia

We provide geochemical analyses and grain size data for a clearly layered, 80 cm thick sedimentary deposit close to a roof collapse in Blanche Cave near Naracoorte in SE South Australia. This deposit contains aeolian material deposited between 40 ka and 14 ka cal BP and which yields airborne sediments spanning the Last Glacial Maximum, a period of time with little information for the Australian continent. The deposit also contains abundant vertebrate fossil material derived from owl pellets, accumulation and pitfall entrapment. Below the studied profile, large vertebrate remains are found but are not discussed here. No Holocene sedimentation occurred at the site examined in the cave, and the top of the sequence is capped with a layer that has been anthropologically disturbed and contains exotic Pinus pollen. Chronologies of the deposit were obtained using two dating techniques: single stage accelerator mass spectrometer (SSAMS) ¹⁴C analysis of 23 charcoal samples and optically stimulated luminescence (OSL) dating of quartz from 6 sediment samples. The ¹⁴C chronology is preferred to describe the history of the deposits since the OSL chronology, which consistently overestimates the associated radiocarbon dates, may be inaccurate due to complexities in calculating dose rates, and may in addition represent the timing of sediment deposition through the cave opening rather than sediment transport to the deposit site. Morphological analysis of single quartz grains and grain size analysis indicate different provenance that is confirmed through the geochemical analyses of bulk sediment. Major elements were measured by X-ray Fluorescence (XRF), trace and rare earth elements by Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA ICP-MS), and Neodymium isotopic ratios were obtained using a Thermal Ionisation Mass Spectrometer (TIMS).Our results indicate that the aeolian material deposited in Blanche Cave over the 40–14 ka cal BP period originated from different sources across South Australia, although Nd isotopes clearly indicate a close association with sediments of the Kanmantoo Group outcropping along the eastern portion of the Mount Lofty Ranges and the Padthaway Ridge further south, both being located to the NW and NNW of the cave. During the latter part of Marine Isotope Stage 3, conditions were wetter and windblown sediment came from the coastal region just north and south of the Coorong Lagoon, with winds originating from the north-northwest. At that time, woody taxa appear to have vegetated the landscape. During the drier phases, especially the Last Glacial Maximum, sediment came from further inland, thus suggesting a different predominant wind direction, more from the northwest. The deglaciation saw material originating from a more northerly direction.     

Wolverine in northern England at about 83,000 yr B.P.: Faunal evidence for climatic change during isotope stage 5

Cave sediments from Stump Cross Cave in northern England contain Pleistocene mammal remains. Uranium-series dating of calcium carbonate deposits closely associated with the fossiliferous horizons has established an absolute age of 83,000 ± 6000 yr B.P. for a faunal assemblage largely comprised of wolverines (Gulo gulo). This date lies firmly within the younger portion of oxygen-isotope stage 5. The occurrence of wolverines in the vicinity of Stump Cross Cave at ca. 83,000 yr B.P. indicates a significant climatic deterioration from ca. 120,000 yr B.P., when an Ipswichian interglacial fauna with hippopotamus was present in this part of northern England.     

Preliminary investigation of Late Pleistocene fauna from Ryonggok Cave No. 1, Sangwon County,North Hwanghae Province,Democratic People's Republic of Korea

The investigation of a limestone cave on the Ryonggok-ri of Sangwon County, North Hwanghae Province, DPRK, has yielded many faunal remains including Late Pleistocene deer, brown bears and horses. Uranium series dating of fossil teeth yielded dates of ~72ka at the base of Layer 2 – the bone-bearing unit – and ~44ka at the top. The rich and diverse mammal remains of Ryonggok Cave No. 1 are indicative of warm and humid temperate conditions during the Late Pleistocene, and reflect the presence of both dense forests and open grassland. In addition, pollen and spores from the site include two families and 24 genera of trees, six families and a genus of grasses and herbs, and two families and six genera of ferns, corroborating the environments inferred from the faunal remains.     

New radiometric and geomorphologic evidences of a last glacial maximum older than 18 ka in SW European mountains: the example of Redes Natural Park (Cantabrian Mountains,NW Spain)

The first numerical age determinations from radiocarbon dating establish the chronology of glacial events in Redes Natural Park (Cantabrian Mountain, NW Spain). A core drilled in an ice-dammed deposit provided a minimum age of 28 990 ± 230 years BP for the maximum glacial expansion (phase I). Another core from a cirque bottom-fill provided organic sediment with 20 640 ± 300 years BP, a minimum age for the first glacial retreat (phase II). Radiometric dating of proglacial deposits interpreted as synchronous with the last glacial maximum phase in neighbouring Comella basin (Picos de Europa), yield ages of 40 480 ± 820 years BP. The chronological data presented in this work are consistent with the model of glacier evolution established in the Pyrénées, with a glacial maximum phase for the last glacial period older than 18 ka.     

Radiocarbon dating from 40 to 60 ka BP at Border Cave,South Africa

We present 21 radiocarbon dates on 19 charcoal samples from the sedimentary sequence preserved in Border Cave, South Africa. The background radiocarbon activity for charcoal from the cave was determined to be 0.050±0.018 percent modern carbon, from the analysis of a radiocarbon-dead sample from unit 5WA. Radiocarbon ages for individual samples ranged from 25.2 to >58.2 ka BP.The error-weighted mean ages for successively older strata are 38.5+0.85/−0.95 ka BP for unit 1WA, 50.2+1.1/−1.0 ka BP for units 2BS.LR.A and 2BS.LR.B, 56.5+2.7/−2.0 ka BP for unit 2BS.LR.C and 59.2+3.4/−2.4 ka BP for unit 2WA. This radiocarbon chronology is consistent with independent chronologies derived from electron spin resonance and amino acid racemization dating. The results therefore provide further evidence that radiocarbon dating of charcoal by the ABOX-SC technique can yield reliable radiocarbon ages beyond 40 ka BP. They also imply that Border Cave 5, a modern human mandible, predates >58.2 ka BP and that the Middle Stone Age (Mode 3)—Later Stone Age (Mode 5) transition of Border Cave was largely effected between ∼56.5 and ∼41.6 ka ago.     

Late Pleistocene fluvial dynamics in the Hochrhein Valley and in the Upper Rhine Graben: chronological frame

During the Pleistocene, the Rhine glacier system acted as a major south–north erosion and transport medium from the Swiss Alps into the Upper Rhine Graben, which has been the main sediment sink forming low angle debris fans. Only some aggradation resulted in the formation of terraces. Optically stimulated luminescence (OSL) and radiocarbon dating have been applied to set up a more reliable chronological frame of Late Pleistocene and Holocene fluvial activity in the western Hochrhein Valley and in the southern part of the Upper Rhine Graben. The stratigraphically oldest deposits exposed, a braided-river facies, yielded OSL age estimates ranging from 59.6 ± 6.2 to 33.1 ± 3.0 ka. The data set does not enable to distinguish between a linear age increase triggered by a continuous autocyclical aggradation or two (or more) age clusters, for example around 35 ka and around 55 ka, triggered by climate change, including stadial and interstadial periods (sensu Dansgaard–Oeschger cycles). The braided river facies is discontinuously (hiatus) covered by coarse-grained gravel-rich sediments deposited most likely during a single event or short-time period of major melt water discharge postdating the Last Glacial Maximum. OSL age estimates of fluvial and aeolian sediments from the above coarse-grained sediment layer are between 16.4 ± 0.8 and 10.6 ± 0.5 ka, and make a correlation with the Late Glacial period very likely. The youngest fluvial aggradation period correlates to the beginning of the Little Ice Age, as confirmed by OSL and radiocarbon ages.     

Speleology and magnetobiostratigraphic chronology of the Buffalo Cave fossil site, Makapansgat, South Africa

Speleological, stratigraphic, paleomagnetic and faunal data is presented for the Buffalo Cave fossil site in the Limpopo Province of South Africa. Speleothems and clastic deposits were sampled for paleomagnetic and mineral magnetic analysis from the northern part of the site, where stratigraphic relationships could be more easily defined and a magnetostratigraphy could therefore be developed for the site. This is also where excavations recovered the fossil material described. A comparison of the east and South African first and last appearance data with the Buffalo Cave fauna was then used to constrain the magnetostratigraphy to produce a more secure age for the site. The magnetostratigraphy showed a change from normal to reversed polarity in the basal speleothems followed by a short normal polarity period in the base of the clastic deposits and a slow change to reversed directions for the remainder of the sequence. The biochronology suggested an optimal age range of between 1.0 Ma and 600,000 yr based on faunal correlation with eastern and southern Africa. A comparison of the magnetobiostratigraphy with the GPTS suggests that the sequence covers the time period from the Olduvai event between 1.95 and 1.78 Ma, through the Jaramillo event at 1.07 Ma to 990,000 yr, until the Bruhnes-Matuyama boundary at 780,000 yr. The faunal-bearing clastic deposits are thus dated between 1.07 Ma and 780,000 yr with the main faunal remains occurring in sediments dated to just after the end of the Jaramillo Event at 990,000 yr.     

Dating megafaunal extinction on the Pleistocene Darling Downs,eastern Australia: the promise and pitfalls of dating as a test of extinction hypotheses

A key to understanding Late Pleistocene megafaunal extinction dynamics is knowledge of megafaunal ecological response(s) to long-term environmental perturbations. Strategically, that requires targeting fossil deposits that accumulated during glacial and interglacial intervals both before and after human arrival, with subsequent palaeoecological models underpinned by robust and reliable chronologies. Late Pleistocene vertebrate fossil localities from the Darling Downs, eastern Australia, provide stratigraphically-intact, abundant megafaunal sequences, which allows for testing of anthropogenic versus climate change megafauna extinction hypotheses. Each stratigraphic unit at site QML796, Kings Creek Catchment, was previously shown to have had similar sampling potential, and the basal units contain both small-sized taxa (e.g., land snails, frogs, bandicoots, rodents) and megafauna. Importantly, sequential faunal horizons show stepwise decrease in taxonomic diversity with the loss of some, but not all, megafauna in the geographically-small palaeocatchment. The purpose of this paper is to present the results of our intensive, multidisciplinary dating study of the deposits (>40 dates). Dating by means of accelerator mass spectrometry (AMS) ¹⁴C (targeting bone, freshwater molluscs, and charcoal) and thermal ionisation mass spectrometry U/Th (targeting teeth and freshwater molluscs) do not agree with each other and, in the case of AMS ¹⁴C dating, lack internal consistency. Scanning electron microscopy and rare earth element analyses demonstrate that the dated molluscs are diagenetically altered and contain aragonite cements that incorporated secondary young C, suggesting that such dates should be regarded as minimum ages. AMS ¹⁴C dated charcoals provide ages that occur out of stratigraphic order, and cluster in the upper chronological limits of the technique (～40–48 ka). Again, we suggest that such results should be regarded as suspicious and only minimum ages. Subsequent OSL and U/Th (teeth) dating provide complimentary results and demonstrate that the faunal sequences actually span ～120–83 ka, thus occurring beyond the AMS ¹⁴C dating window. Importantly, the dates suggest that the local decline in biological diversity was initiated ～75,000 years before the colonisation of humans on the continent. Collectively, the data are most parsimoniously consistent with a pre-human climate change model for local habitat change and megafauna extinction, but not with a nearly simultaneous extinction of megafauna as required by the human-induced blitzkrieg extinction hypothesis. This study demonstrates the problems inherent in dating deposits that lie near the chronological limits of the radiocarbon dating technique, and highlights the need to cross-check previously-dated archaeological and megafauna deposits within the timeframe of earliest human colonisation and latest megafaunal survival.     

Exploring Paleogeographic Conditions at Two Paleolithic Sites in Navarino,Southwest Greece,Dated by Optically Stimulated Luminescence

In this paper, we employed optically stimulated luminescence (OSL) dating of sediments from two archaeological sites located in Navarino, Messenia, southwestern Greece, to deduce a chronology for the archaeological sites. Archaeological surveys identified two Paleolithic sites on fossilized coastal dunes. Chipped stone tool assemblages were identified eroding out of paleosols developed in the dunes. The assemblage from one site lacked distinct typological features and hence it was difficult to assign to a chronological period. The lithic assemblage from the other site contained artifacts that typologically can be assigned to the Levallois‐Mousterian. Previous efforts to date the artifact‐bearing sediments at these sites were unsuccessful. Using newer OSL dating methods (i.e., the Single‐Aliquot‐Regenerated Dose protocol and thermally transferred‐OSL[TT‐OSL]), we attempted to construct a chronological framework for Late Pleistocene human activity in the southwest Peloponnese. The revised OSL chronology for the first site is 28 ± 5 ka, while a luminescence age of 8 ± 1 ka for the second site only represents a later deflation event. Within the framework of Quaternary environmental change, the location of Paleolithic sites relative to the coast would have changed during the course of the Pleistocene. As a result, Paleolithic exploitation strategies would have been strongly influenced by the changing coastal geomorphology, encouraging hominids to adapt to new distributions of resources. OSL dating of the archaeological sites allowed us to connect traces of hominid activity with climatic stadials/interstadials of the later Pleistocene derived from existing relative sea‐level curves. Ultimately, these data permitted the reconstruction of regional Late Pleistocene paleogeography. © 2012 Wiley Periodicals, Inc.     

Late Pleistocene glaciation of the Kleiner Arbersee area in the Bavarian Forest,south Germany

During Pleistocene mountain glaciation of the Bavarian Forest, south Germany, the Wurmian Kleiner Arbersee glacier left behind glacial landforms and sediments which are described, classified and interpreted using a combination of geomorphological, sedimentological, pedological, surveying and absolute dating methods. The latest Kleiner Arbersee glacier with a maximum length of 2600 m, a minimum width of 800 m and a thickness of 115 m formed an elongated cirque, four lateral moraines, one divided end moraine, one recessional moraine, a proglacial lake and a basin in which lake Kleiner Arbersee was established after deglaciation. Beyond the glacial limit the landscape is denuded by periglacial slope deposits which are differentiated from the glacigenic sediments based upon clast fabrics, clast shapes and sediment consolidation. Within the glacial limit sandy–gravelly to silty–gravelly tills are widely distributed, whereas glaciolacustrine sediments are restricted to a small area north of the lake. Small variations in the sand and silt fraction of the tills are explained by melt-out processes. Quartz, mica and chlorite derived from gneiss bedrock are dominant in the clay mineral spectrum of tills, but also gibbsite as a product of pre-Pleistocene weathering is present giving evidence of glacially entrained saprolites. An IRSL-date of glaciolacustrine sediments (32.4±9.4 ka BP) confirms the Wurmian age for the glaciation and radiocarbon ages of the basal sediments (12.3±0.4 and 12.5±0.2 ka BP uncalibrated) in the lake Kleiner Arbersee prove that the basin was ice-free before the Younger Dryas.     

Stratigraphy and optically stimulated luminescence (OSL) dating of a Quaternary sequence along the Dong Nai River, southern Vietnam

The pre-Holocene Cenozoic sequence outcrops in the terrestrial part of the eastern margin of the Mekong Basin. However, the stratigraphy of the sequence is still unclear. Its detailed stratigraphy and chronology were therefore studied along the Dong Nai River, southern Vietnam, and the lithofacies and the relations among the formations were investigated from the outcrops. The ages of the deposits were determined by using optically stimulated luminescence (OSL) dating.The Ba Mieu Formation was deposited about 176±52 ka during marine isotope stage (MIS) 7–6. The Thu Duc Formation was deposited about 97±27 ka during MIS 5. Both the Ba Mieu and Thu Duc formations are composed of fluvial and tidally influenced coastal deposits. The newly proposed Nhon Trach Formation was originally an eolian (blanket) deposit, but it has been partly reworked by fluvial processes. The Nhon Trach Formation was deposited about 10.9±4.7 ka, in the last part of the Pleistocene to the beginning of the Holocene. The OSL ages for the Ba Mieu, Thu Duc, and Nhon Trach formations are younger than the ages previously assigned to these formations.     

Lateglacial and early Holocene surface exposure ages of glacial boulders in the Taiwanese high mountain range

Glacial landforms and sediments mapped in three presently unglaciated mountain massifs, the Nanhuta Shan, the Hsueh Shan and the Yushan, support the concept of repeated, multi-stage glaciations in the Taiwanese high mountain range during the late Pleistocene. New results from surface exposure dating using in situ produced cosmogenic ¹⁰Be measured in samples taken from erratic and moraine boulders in Nanhuta Shan at altitudes between 3100 and 3500 m are presented here. The results confirm independent and previously reported Optically Stimulated Luminescence (OSL) ages and ¹⁰Be exposure ages from glacial deposits in the same area and suggest a Lateglacial and early Holocene glaciation, the so called Nanhuta glacier advance with two substages at about 12–15 ka and 9.5 ka BP. The respective equilibrium line altitudes (ELA) were calculated at 3340 m and 3440 m with corresponding ELA depressions of 610 ± 100 m and 510 ± 100 m relative to the present day (theoretical) ELA, which is estimated to be at about 3950 ± 100 m in Taiwan. Large-scale erosional landforms indicate a much wider glacier extent during an earlier stage, which is not dated in Nanhuta Shan so far. Luminescence dating from near Hsueh Shan suggests an age of marine isotope stage (MIS) 4 for this stage.     

Reevaluating the tectonic uplift of western Mount Carmel, Israel, since the middle Pleistocene

Reevaluation of geological and archaeological evidence from western Mount Carmel constrains its maximal tectonic uplift since the Middle Pleistocene. Tabun Cave, presently 45 m above sea level (asl), revealed human occupation from about 600 ka to 90 ka before present. The 25 m thick archaeological strata at Tabun are composed of laminated fine sand, silt and clays. Moreover, no marine deposits were found in Tabun or nearby caves. Since sea level in the last 600 ka reached a maximal of 5 to 10 m asl, Tabun Cave could not have been uplifted since then by more than 35 to 40 m, that is a maximal average rate of 58 to 67 mm/ka.     

Geochemistry and U-series dating of Holocene and fossil marine hydrothermal manganese deposits from the Izu-Ogasawara arc

This study investigated Holocene and fossil hydrothermal manganese deposits in the Izu-Ogasawara arc. Mineralogically, these deposits comprise 10 Å and 7 Å manganate minerals, and the fossil samples showed higher 10 Å stabilities. Chemical compositions of the Holocene samples are typical of other hydrothermal manganese deposits, including low Fe/Mn ratios, low trace metals, and low rare earth elements. Although the fossil samples generally have similar chemical characteristics, they exhibit significant enrichment in Ni, Cu, Zn, Cd, Ba, REE, Tl, and Pb contents. Furthermore, the chondrite-normalized REE patterns showed more light REE enrichment trends. These chemical characteristics suggest post-depositional uptake of these metals from seawater. U-Th dating of a Holocene hydrothermal manganese deposit from the Kaikata Seamount indicated 8.8 ± 0.94 ka for the uppermost layer and downward growth beneath the seafloor with a growth rate of ca. 2 mm/kyr. This is approximately three orders of magnitude faster than that of hydrogenetic ferromanganese crusts. U-Pb age of a fossil hydrothermal manganese deposit from the Nishi-Jokyo Seamount showed 4.4 ± 1.6 Ma, which was contemporary with basaltic volcanism (5.8 ± 0.3 Ma). Hydrothermal manganese deposits contain high concentrations of high value Mn, but only small amounts of valuable minor metals; their ages constrain the periods of past hydrothermal activity and provide a vector to explore for polymetallic sulfide deposits.     

Late Quaternary environmental and human events at En Gedi, reflected by the geology and archaeology of the Moringa Cave (Dead Sea area, Israel)

The Moringa Cave within Pleistocene sediments in the En Gedi area of the Dead Sea Fault Escarpment contains a sequence of various Pleistocene lacustrine deposits associated with higher-than-today lake levels at the Dead Sea basin. In addition it contains Chalcolithic remains and 5th century BC burials attributed to the Persian period, cemented and covered by Late Holocene travertine flowstone. These deposits represent a chain of Late Pleistocene and Holocene interconnected environmental and human events, echoing broader scale regional and global climate events. A major shift between depositional environments is associated with the rapid fall of Lake Lisan level during the latest Pleistocene. This exposed the sediments, providing for cave formation processes sometime between the latest Pleistocene (ca. 15 ka) and the Middle Holocene (ca. 4500 BC), eventually leading to human use of the cave. The Chalcolithic use of the cave can be related to a relatively moist desert environment, probably related to a shift in the location of the northern boundary of the Saharo-Arabian desert belt. The travertine layer was U-Th dated 2.46 ± 0.10 to 2.10 ± 0.04 ka, in agreement with the archaeological finds from the Persian period. Together with the inner consistency of the dating results, this strongly supports the reliability of the radiometric ages. The 2.46-2.10 ka travertine deposition within the presently dry cave suggests a higher recharge of the Judean Desert aquifer, correlative to a rising Dead Sea towards the end of the 1st millennium BC. This suggests a relatively moist local and regional climate facilitating human habitation of the desert.     

北美五大湖区晚更新世劳伦泰德冰盖演化年代学综述及石英光释光测年的初步尝试

北美五大湖区的安大略湖北岸Don Valley Brickyard、Scarborough Bluffs、Bowmanville Bluffs剖面共同构成了北美东北部最长也是最厚的陆地第四纪沉积记录, 较完整地记录了晚更新世劳伦泰德冰盖(the Laurentide Ice Sheet)的演化. 晚更新世劳伦泰德冰盖演化的重建有赖于这些经典剖面中重要沉积地层单元的准确年代学控制. 传统的地层年代学主要是依靠少量¹⁴C年代, 将主要的混杂堆积单元(diamicton)解释为气候变冷环境下的冰川扩张, 并与指示全球冰量变化的深海氧同位素曲线一一比对建立起来的. 这样建立起来的年代学存在很大的不确定性. 20世纪80-90年代的少量热释光年代也不相吻合, 最近的13个长石红外释光定年则只集中于Bowmanville Bluffs的一个分层, 并未建立整个剖面的地层年代学, 使这些经典沉积剖面的年代学一直没有得到系统的建立. 应用石英光释光SAR-SGC法测试了Bowmanville Bluffs剖面Glaciofluvial Sand单元的2个冰水沉积样品, 年代结果分别为(41.6±3.8) ka、(48.1±4.4) ka, 分析表明这一年代结果偏老, 石英颗粒可能晒褪不完全. 由于大测片无法识别晒褪不完全的颗粒, 因此, 测试更多的剖面序列的光释光年代并尝试采用粗颗粒小测片或单颗粒技术解决样品颗粒晒褪不完全的问题将是必要的.     

An absolute chronology for the raised beach and associated deposits at Sewerby,East Yorkshire,England

The raised beach sediments revealed in the cliffs at Sewerby, East Yorkshire are widely regarded as Ipswichian in age. Previously reported evidence for this dating is reviewed and new results from a range of luminescence dating techniques applied to the blown sand deposit overlying the raised beach are reported. These provide the first absolute date for the Sewerby site of 120.84 ± 11.82 ka, which places the blown sand at the boundary between oxygen isotope stages (OIS) 5e and 5d. As the underlying raised beach is little older than the blown sand, it probably formed during OIS Stage 5e as suggested by the faunal evidence.