Radiocarbon dating of well-preserved, in-place vegetation exposed by the retreating Quelccaya Ice Cap of southeastern Peru constrains the last time the ice cap's extent was smaller than at present. Seventeen plant samples from two sites along the central western margin collectively date to 4700 and 5100 cal yr BP and strongly indicate that current ice cap retreat is unprecedented over the past ∼ 5 millennia. Seventeen vegetation samples interbedded in a nearby clastic sedimentary sequence suggest ice-free conditions at this site from ∼ 5200 to at least ∼ 7000 cal yr BP, and place minimum constraint on early- to mid-Holocene ice cap extent.

Pollen analysis from a peat core 7.0 m in length, taken from a bog near Bisoca, in a mid-altitude area of the Buzăului Subcarpathian mountains, is used to reconstruct the postglacial vegetation history of the region. The vegetation record, which is supported by twelve 14C dates, starts at the end of the Late Glacial period. At the Late Glacial/Holocene transition, open vegetation was replaced by forest, suggesting a fast response to climatic warming. The Holocene began with the expansion of Betula, Pinus and Ulmus, followed, after 11,000 cal yr BP, by Fraxinus, Quercus, Tilia and Picea. The rapid expansion of these taxa may be due to their existence in the area during the Late Glacial period. At ca. 9200 cal yr BP, Corylus expanded, reaching a maximum after 7600 cal yr BP. The establishment of Carpinus occurred at ca. 7200 cal yr BP, with a maximum at ca. 5700 cal yr BP. Fagus pollen is regularly recorded after 7800 cal yr BP and became dominant at ca. 2000 cal yr BP. The first indications of human activities appear around 3800 cal yr BP.

Tephra-dated, high-resolution pollen profiles from Ketilsstaðir, southern Iceland, indicate a largely unwooded pre-settlement environment, a probable consequence of the exposed coastal location. The degree of change associated with the Norse landnám is more limited than in many Icelandic pollen diagrams. There are three main periods of change in the post-settlement vegetational development of the area. Firstly, Norse settlement affected the hydrology of the bog, resulting in the near-disappearance of Sphagnum and agricultural activity led to a reduction of some species (e.g. Angelica spp. and Salix). Secondly, the establishment of probable permanent settlement in the mid-11th century AD initiated expansion of such apophytic taxa as Plantago spp. Lactuceae, Ranunculus spp. and Pteridophytes. Thirdly, the ≥ 10 cm thick Katla tephra, deposited in AD 1357, enhanced drainage of the bog surface, favouring dryland taxa (e.g. Poaceae, Galium and Lactuceae). The tephra deposit and the associated drainage probably caused or contributed to the local extinction of the wetland beetle Hydraena britteni. The study has enabled a series of natural and humanly-related issues to be addressed including tephra-vegetation relationships, the anthropogenic reduction in plant diversity, and comparisons between historical and environmental settlement records.

Pollen and organic-walled dinoflagellate cyst assemblages from core GeoB 9503-5 retrieved from the mud-belt (∼ 50 m water depth) off the Senegal River mouth have been analyzed to reconstruct short-term palaeoceanographic and palaeoenvironmental changes in subtropical NW Africa during the time interval from ca. 4200 to 1200 cal yr BP. Our study emphasizes significant coeval changes in continental and oceanic environments in and off Senegal and shows that initial dry conditions were followed by a strong and rapid increase in humidity between ca. 2900 and 2500 cal yr BP. After ca. 2500 cal yr BP, the environment slowly became drier again as indicated by slight increases in Sahelian savannah and desert elements in the pollen record. Around ca. 2200 cal yr BP, this relatively dry period ended with periodic pulses of high terrigenous contributions and strong fluctuations in fern spore and river plume dinoflagellate cyst percentages as well as in the fluxes of pollen, dinoflagellate cysts, fresh-water algae and plant cuticles, suggesting “episodic flash flood” events of the Senegal River. The driest phase developed after about 2100 cal yr BP.

Large-scale atmospheric circulation patterns determine the quantity and seasonality of precipitation, the major source of water in most terrestrial ecosystems. Oxygen isotope (δ18O) dynamics of the present-day hydrologic system in the Palouse region of the northwestern U.S.A. indicate a seasonal correlation between the δ18O values of precipitation and temperature, but no seasonal trends of δ18O records in soil water and shallow groundwater. Their isotope values are close to those of winter precipitation because the Palouse receives ∼ 75% of its precipitation during winter. Palouse Loess deposits contain late Pleistocene pedogenic carbonate having ca. 2 to 3‰ higher δ18O values and up to 5‰ higher carbon isotope (δ13C) values than Holocene and modern carbonates. The late Pleistocene δ18O values are best explained by a decrease in isotopically light winter precipitation relative to the modern winter-dominated infiltration. The δ13C values are attributed to a proportional increase of atmospheric CO2 in soil CO2 due to a decrease in soil respiration rate and 13C discrimination in plants under much drier paleoclimate conditions than today. The regional climate difference was likely related to anticyclonic circulation over the Pleistocene Laurentide and Ice Sheet.

Analysis of pollen, spores, macrofossils, and lithology of an AMS 14C-dated core from a subarctic fen on the Kenai Peninsula, Alaska reveals changes in vegetation and climate beginning 14,200 cal yr BP. Betula expansion and contraction of herb tundra vegetation characterize the Younger Dryas on the Kenai, suggesting increased winter snowfall concurrent with cool, sunny summers. Remarkable Polypodiaceae (fern) abundance between 11,500 and 8500 cal yr BP implies a significant change in climate. Enhanced peat preservation and the occurrence of wet meadow species suggest high moisture from 11,500 to 10,700 cal yr BP, in contrast to drier conditions in southeastern Alaska; this pattern may indicate an intensification and repositioning of the Aleutian Low (AL). Drier conditions on the Kenai Peninsula from 10,700 to 8500 cal yr BP may signify a weaker AL, but elevated fern abundance may have been sustained by high seasonality with substantial snowfall and enhanced glacial melt. Decreased insolation-induced seasonality resulted in climatic cooling after 8500 cal yr BP, with increased humidity from 8000 to 5000 cal yr BP. A dry interval punctuated by volcanic activity occurred between 5000 and 3500 cal yr BP, followed by cool, moist climate, coincident with Neoglaciation. Tsuga mertensiana expanded after ~ 1500 cal yr BP in response to the shift to cooler conditions.

The morphometrical analysis of gnammas (weathering pits) in granite landscapes has been used to establish the relative chronology of recent erosive surfaces and to provide the weathering history in a region. To test the validity of gnammas as relative chronometer indicators, and the reliability of the obtained weathering record, two sites have been studied in Serra da Estrela, Portugal. The first site is within the limits of the glacier that existed in these mountains during the last glaciation, whereas the second site is located in an unglaciated sector of the mountains, which preserves a longer record of weathering in the bedrock surface. The number of gnamma weathering phases recorded in the latter site (8) is larger than those from the former (6). Correlation between both measurement stations based on morphometrical criteria is excellent for the younger six weathering phases (1 to 6). Consequently, the parameter used for relative chronology (δ-value) has been verified to be age dependent, although absolute values are modulated by microclimate due to altitude variations. The weathering record was essentially duplicated once the surfaces at both sites were exposed, demonstrating the reliability of gnamma evolution as a post-glacial environmental indicator for the region.

Glacial deposits are present at the head of the Ürümqi River valley, Tianshan, Central Asia. 10Be surface exposure ages of 15 boulders from three sites along a 12 km valley transect range from 9 to 21 ka suggesting emplacement by glacial retreat and advance commencing at the global last glacial maximum (LGM) and most likely abating in the early Holocene. Although the age spread for a given locality is not small, perhaps indicating post-depositional reworking, maximum ages per site are either coeval with or are post-LGM and inconsistent with previous pre-LGM electron spin resonance ages.

Late-glacial (17–11 cal ka BP) pollen records from midwestern North America show similar vegetation trends; however, poor dating resolution, wide-interval pollen counts, and variable sedimentation rates have prevented the direct correlation with the North Atlantic Event Stratigraphy as represented in the Greenland ice-core records, thus preventing the understanding of the teleconnections and mechanisms of late-Quaternary events in the Northern Hemisphere. The widespread occurrence of late-glacial vegetation and climates with no modern analogs also hinders late-glacial climate reconstructions. A high-resolution pollen record with a well-controlled age model from Crystal Lake in northeastern Illinois reveals vegetation and climate conditions during the late-glacial and early Holocene intervals. Late-glacial Crystal Lake pollen assemblages, dominated by Picea mariana and Fraxinus nigra with lesser amounts of Abies and Larix, suggest relatively wet climate despite fluctuations between colder and warmer temperatures. Vegetation changes at Crystal Lake are coeval with millennial-scale trends in the NGRIP ice-core record, but major shifts in vegetation at Crystal Lake lag the NGRIP record by 300–400 yr. This lag may be due to the proximity of the Laurentide ice sheet, the ice sheet's inherent slowness in response to rapid climate changes, and its effect on frontal boundary conditions and lake-effect temperatures.

The late Quaternary paleoclimate of eastern Beringia has primarily been studied by drawing qualitative inferences from vegetation shifts. To quantitatively reconstruct summer temperatures, we analyzed lake sediments for fossil chironomids, and additionally we analyzed the sediments for fossil pollen and organic carbon content. A comparison with the δ18O record from Greenland indicates that the general climatic development of the region throughout the last glaciation–Holocene transition differed from that of the North Atlantic region. Between ∼ 17 and 15 ka, mean July air temperature was on average 5°C colder than modern, albeit a period of near-modern temperature at ∼ 16.5 ka. Total pollen accumulation rates ranged between ∼ 180 and 1200 grains cm− 2 yr− 1. At ∼ 15 ka, approximately coeval with the Bølling interstadial, temperatures again reached modern values. At ∼ 14 ka, nearly 1000 yr after warming began, Betula pollen percentages increased substantially and mark the transition to shrub-dominated pollen contributors. Chironomid-based inferences suggest no evidence of the Younger Dryas stade and only subtle evidence of an early Holocene thermal maximum, as temperatures from ∼ 15 ka to the late Holocene were relatively stable. The most recognizable climatic oscillation of the Holocene occurred from ∼ 4.5 to 2 ka.

Late Quaternary terrestrial climate records from the semi-arid zone of the Western Cape of South Africa are rare. However, palaeoenvironmental information may be inferred from ancient termite mounds of the region. Calcrete lenses in these mounds have δ13C and δ18O values that show systematic changes with radiocarbon dates, which range from 33,629–36,709 to 21,676–23,256 cal yr BP. These dates confirm that these heuweltjies had been present in the landscape since the last glacial period. The decrease in δ13C and δ18O from 33,629–36,709 to 21,676–23,256 cal yr BP indicates that climate information is recorded by the calcretes. It is suggested that a progressive decline in air temperature and an increase in moisture availability, and a decline in abundance of C4 or CAM plants, occurred in the region during the time heuweltjie calcite precipitated.

The Pliocene and Pleistocene continental sedimentary records of the western sector of the Granada Basin, southern Spain, consist of alternating fluvial and lacustrine/palustrine sediments. Two Quaternary sections from this sector have been sampled: Huétor Tájar and Tojaire. They have yielded remains of rodents, insectivores and lagomorphs. The presence in the Huétor Tájar and Tojaire sections of Mimomys, Apodemus atavus, Castillomys rivas and two different species of Allophaiomys, indicates an Early Pleistocene age. These deposits, which are related to a fluvio-lacustrine system, can be differentiated from an older (Pliocene) braided fluvial system. Their dating has important repercussions on the paleogeographic reconstruction of the basin. The conditions inferred from the ecological preferences of the small mammal associations are wet and cold. These associations suggest a predominance of open herbaceous habitats, followed by forested habitats; semiaquatic habitats are the least represented.

Timpanogos Cave, located near the Wasatch fault, is about 357 m above the American Fork River. Fluvial cave sediments and an interbedded carbonate flowstone yield a paleomagnetic and U–Th depositional age of 350 to 780 ka. Fault vertical slip rates, inferred from calculated river downcutting rates, range between 1.02 and 0.46 mm yr− 1. These slip rates are in the range of the 0–12 Ma Wasatch Range exhumation rate (∼ 0.5–0.7 mm yr− 1), suggesting that the long-term vertical slip rate remained stable through mid-Pleistocene time. However, the late Pleistocene (0–250 ka) decelerated slip rate (∼ 0.2–0.3 mm yr− 1) and the accelerated Holocene slip rate (∼ 1.2 mm yr− 1) are consistent with episodic fault activity. Assuming that the late Pleistocene vertical slip rate represents an episodic slowing of fault movement and the long-term (0–12 Ma) average vertical slip rate, including the late Pleistocene and Holocene, should be ∼ 0.6 mm yr− 1, there is a net late Pleistocene vertical slip deficit of ∼ 50–75 m. The Holocene and late Pleistocene slip rates may be typical for episodes of accelerated and slowed fault movement, respectively. The calculated late Pleistocene slip deficit may mean that the current accelerated Wasatch fault slip rate will extend well into the future.

Coprolites can provide detailed information about the nutritional habits and digestive processes of the animals that produced them and may also yield information about the palaeoenvironment in which the animal existed. To test the utility of the lipid biomarker approach to coprolite analysis, lipids were extracted from a coprolite of the Pleistocene ground sloth Nothrotheriops shastensis. Gas chromatography/mass spectrometry results revealed a dominant spiroketal sapogenin component identified, using nuclear magnetic resonance spectroscopy, as epismilagenin. The dominance of epismilagenin is probably due to ingestion of Yucca spp. and Agave spp., which is consistent with previous studies on the diet of this species.

The sediments in Lake Huguang Maar in coastal South China were previously thought to originate mainly from wind-blown dust transported from North China, such that the lake sediments recorded the varying strength of the Asian winter monsoon. An alternative explanation was that the local pyroclastic rocks supplied the lake sediments, but the actual contributions from the different sources remained unclear. Geochemical analyses including 87Sr/86Sr and 143Nd/144Nd and trace elements support the local pyroclastic rock as the dominant source: <22% of the total Sr in the lake sediments and ∼ 17% of the Nd arises from the distant source. Nb/Ta and Zr/Hf for the lake sediments are identical to those for the local rock but differ from the ratios for the wind-blown dust, and chondrite-normalized rare earth element patterns for the lake sediments are similar to those for the local rock and soil, but differ from those for the distant source. The sediments in Lake Huguang Maar are probably input into the lake through runoff and thus controlled by the hydrology of the lake. Wind-blown dust transported by the Asian winter monsoon from arid North China is only a minor contribution to the sediments.

Although the carbon-reservoir problem with bulk-sediment radiocarbon dates from lakes has long been recognized, many synoptic studies continue to use chronologies derived from such dates. For four sites in central North America, we evaluate chronologies based on conventional radiocarbon dates from bulk sediment versus chronologies based on accelerator mass spectrometry (AMS) radiocarbon dates from terrestrial plant macrofossils. The carbon-reservoir error varies among sites and temporally at individual sites from 0 to 8000 yr. An error of 500–2000 yr is common. This error has important implications for the resolution of precise event chronologies.