An understanding of the growth and demise of ice sheets over North America is essential to inform future climate models. One poorly studied subject is the glacial dynamics during interstadial Marine Isotope Stage (MIS) 3 (57–29 ka). To better constrain the southern margin of the Laurentide Ice Sheet during this time period, we re-examined a stratigraphic sequence in southeast Manitoba, Canada, and provide robust evidence for advance and retreat of ice. Around 46.6 ± 5.1 ka (1σ error), fluvial sands were deposited under similar precipitation and significantly cooler summer temperatures than present-day. Ice then advanced south over the area, before retreating once again and a return to boreal forest and grassland conditions. The area was then covered by proglacial Lake Vita, dammed by ice to the north. Geochronology constraints indicate Lake Vita existed from ca. 44.3 ± 3.6 to 30.4 ± 2.3 ka (1σ error), although gaps in the optical and finite radiocarbon ages suggest either a lack of data or plausible temporary ice-margin advances during this time period. Ice covering most of Manitoba during MIS 3 is in line with global δ18O records, and glacially influenced sediment deposition in the Mississippi River basin.

Geomorphic, stratigraphic and geochronological evidence from northeast British Columbia (Canada) indicates that, during the late Wisconsinan (approximately equivalent to marine oxygen isotope stage [MIS] 2), a major lobe of western-sourced ice coalesced with the northeastern-sourced Laurentide Ice Sheet (LIS). High-resolution digital elevation models reveal a continuous 75 km-long field of streamlined landforms that indicate the ice flow direction of a major northeast-flowing lobe of the Cordilleran Ice Sheet (CIS) or a montane glacier (>200 km wide) was deflected to a north-northwest trajectory as it coalesced with the retreating LIS. The streamlined landforms are composed of till containing clasts of eastern provenance that imply that the LIS reached its maximum extent before the western-sourced ice flow crossed the area. Since the LIS only reached this region in the late Wisconsinan, the CIS/montane ice responsible for the streamlined landforms must have occupied the area after the LIS withdrew. Stratigraphy from the Murray and Pine river valleys supports a late Wisconsinan age for the surface landforms and records two glacial events separated by a non-glacial interval that was dated to be of middle Wisconsinan (MIS 3) age.

The synthesis of paleoclimatic archives provided by loess and alluvial sequences of central Argentina has been hindered by the lack of a cohesive lithostratigraphic framework extending across the Chaco–Pampean plains and catchments of the Rios Desaguadero, Colorado, and Negro. This condition originates in part from the dearth of absolute chronological controls. The occurrence of discrete tephra layers across this region may provide an opportunity to address this deficiency if a tephrochronological framework can be established. The potential of such a project is assessed within the context of a pilot study constrained within alluvial sequences of central western Argentina proximal to potential source vents in the Southern Volcanic Zone. The intersite discrimination and correlation of tephra layers on a geochemical basis is examined, with indirect chronological control for the eruption of each generated by optical dating. Alluvial sediments on either side of each of five tephra units at a type site were dated using the optically stimulated luminescence of fine-silt-sized quartz, thus providing an age control on each tephra (ca. 24,000, 30,000, 32,000, 39,000, and 48,000 yr). The geochemical composition of each tephra was derived. Using these data, tephra layers at other sites in the study area were geochemically analyzed and in instances of statistical concordance in major oxide structure, correlated to the type site and therefore ascribed ages. This methodology identified a further sixth volcanic event between ca. 24,000 and 30,000 yr not registered by type-site tephras. The extension of this initial tephrochronological framework beyond the alluvial sequences of central western Argentina is encouraged by the occurrence of geochemically distinct tephra verified and dated in this study.

The Nihewan Basin is a key region for studying the Palaeolithic archaeology of East Asia. However, because of the lack of suitable dating methods and representative lithic technologies in this region, the ‘Middle Palaeolithic’ sites in this basin have been designated based mainly on stratigraphic correlation, which may be unreliable. In this study, three Palaeolithic sites, Motianling, Queergou and Banjingzi, which have been assigned previously to the ‘Middle Palaeolithic’, are dated based on luminescence dating of K-feldspar grains. Our results show that the cultural layers at Motianling, Queergou and Banjingzi have ages of 315 ± 13, 268 ± 13 and 86 ± 4 ka (corresponding to Marine Isotope Stages 9, 8 and 5), respectively, suggesting that Motianling and Queergou should be assigned to the Lower Palaeolithic, while the age of Banjingzi is consistent with a Middle Palaeolithic attribution. Our results suggest that reassessing the age of ‘Middle Palaeolithic’ sites in the Nihewan Basin, and elsewhere in North China, is crucial for understanding the presence or absence of the Middle Palaeolithic phase in China. Our dating results also indicate that the Sanggan River developed sometime between about 270 and 86 ka ago.

The deposits of Glacial Lake Quincy overlie a diamicton associated with the classically defined Illinoian limit in central Indiana. This lake covered at least 180 km2 with a depth of > 20 m and developed when the Illinoian ice sheet retreated 15 km from the maximum limit, causing lake impoundment against Devore Ridge. Overflow from Glacial Lake Quincy eroded across the ridge forming a number of steeped-walled outlets. A section along Mill Creek exposes a sedimentologic sequence associated with Glacial Lake Quincy from a subglacial diamicton to ice-proximal to ice-distal glacial lacustrine sediments. We report new optical ages by multiple aliquot regenerative dose procedure for the fine-grained rhythmically bedded sediments presumed to represent the lowest energy depositional facies, dominated by suspension settling, which maximized sunlight exposure. In turn, optical ages were determined on the fine-grained (4-11 μm) polymineral and quartz fractions under infrared and blue excitation, which yielded statistically similar ages. Optical ages span from ca. 170 to 108 ka, with the average of 16 optical ages indicating deglaciation at ca. 135 ka, generally coincident with Marine Oxygen Isotope Stage 6-to-5 transition and rise in global sea level.

Oxygen and carbon isotope ratios of soil carbonate and carbon isotope ratios of soil organic matter (SOM) separated from three cores, Kalpi, IITK and Firozpur, of the Ganga Plain, India are used to reconstruct past rainfall variations and their effect on ambient vegetation. The δ18O values of soil carbonate (δ18OSC) analyzed from the cores range from −8.2 to −4.1‰. Using these variations in δ18OSC values we are able, for the first time, to show periodic change in rainfall amount between 100 and 18 ka with three peaks of higher monsoon at about 100, 40 and 25 ka. The estimation of rainfall variations using δ18O value of rainwater-amount effect suggests maximum decrease in rainfall intensity (~ 20%) during the last glacial maximum. The δ13C values of soil carbonate (δ13CSC) and SOM (δ13CSOM) range from −6.3 to + 1.6‰ and −28.9 to −19.4‰, respectively, implying varying proportions of C3 and C4 vegetations over the Ganga Plain during the last 100 ka. The comparison between monsoonal rainfall and atmospheric CO2 with vegetation for the time period 84 to 18 ka indicate that relative abundances of C3 and C4 vegetations were mainly driven by variations in monsoonal rainfall.

Eight continuous corings in the west-central Netherlands show a 15 to 25 m thick stacked sequence of sandy to gravelly channel-belt deposits of the Rhine-Meuse system. This succession of fluvial sediments was deposited under net subsiding conditions in the southern part of the North Sea Basin and documents the response of the Rhine-Meuse river system to climate and sea-level change and to the glaciation history. On the basis of grain size characteristics, sedimentological structures, nature and extent of bounding surfaces and palaeo-ecological data, the sequence was subdivided into five fluvial units, an estuarine and an aeolian unit. Optical dating of 34 quartz samples showed that the units have intra Saalian to Weichselian ages (Marine Isotope Stages 8 to 2). Coarse-grained fluvial sediments primarily deposited under cold climatic conditions, with low vegetation cover and continuous permafrost. Finer-grained sediments generally deposited during more temperate climatic conditions with continuous vegetation cover and/or periods of sea-level highstand. Most of the sedimentary units are bounded by unconformities that represent erosion during periods of climate instability, sea-level fall and/or glacio-isostatic uplift.

The original distribution pattern of Middle-Palaeolithic artefacts may be affected by tectonic movement, sedimentation and periglacial processes. This is e.g. the case in the coversand area of Limburg and Eastern Brabant (NL), where the occurrence of numerous finds in a SW-NE trending zone across the Roer Valley Graben is considered enigmatic. In order to elucidate the processes affecting the spatial distribution and the chance of recovery of such artefacts, we investigated a site in Nederweert. At this site, several Middle-Palaeolithic artefacts had been recovered earlier from unexpectedly shallow depths. A test pit profile and grain size analyses revealed that the shallow sediments at this site have been affected by intense, multi-phase cryoturbation, which has deformed the sand and loam layers and partially mixed them thoroughly. As a result, optically stimulated luminescence dating of these sediments yielded widely scattered single-aliquot equivalent dose distributions. Using a Finite Mixture Model (FMM), it was estimated that cryoturbation caused mixing of sediments deposited between 12 and 50 ka with sediment grains deposited between 60-150 ka. The latter material is probably the original context of the Middle-Paleolithic artefacts. Apparently, cryoturbation and potentially other periglacial processes have transported artefacts closer to the surface. Based on these results, we suggest that the occurrence of Middle-Palaeolithic artefacts is caused by (1) the tectonically-induced spatial distribution of layers of this age and (2) periglacial processes having caused migration of artefacts towards the surface. Although periglacial processes may facilitate finding Middle Palaeolithic artefacts, they may severely disturb the original context to such an extent that Middle Palaeolithic sites can no longer be identified. The results of this study form a basis for improving the Indicative Map of Archaeological Values that is used to predict the presence of archaeological sites. The insights gained are also relevant to other areas where Middle-Palaeolithic sites are affected by periglacial processes.