Herein we document and interpret an absolute chronological dating attempt using geomagnetic paleointensity data from a post-glacial sediment drape on the western Antarctic Peninsula continental shelf. Our results demonstrate that absolute dating can be established in Holocene Antarctic shelf sediments that lack suitable material for radiocarbon dating. Two jumbo piston cores of 10-m length were collected in the Western Bransfield Basin. The cores preserve a strong, stable remanent magnetization and meet the magnetic mineral assemblage criteria recommended for reliable paleointensity analyses. The relative paleomagnetic intensity records were tuned to published absolute and relative paleomagnetic stacks, which yielded a record of the last ∼8500 years for the post-glacial drape. Four tephra layers associated with documented eruptions of nearby Deception Island have been dated at 3.31, 3.73, 4.44, and 6.86 ± 0.07 ka using the geomagnetic paleointensity method. This study establishes the dual role of geomagnetic paleointensity and tephrochronology in marine sediments across both sides of the northern Antarctic Peninsula.

We present a varve thickness chronology from glacier-dammed Iceberg Lake in the southern Alaska icefields. Radiogenic evidence confirms that laminations are annual and record continuous sediment deposition from A.D. 442 to A.D. 1998. Varve thickness is positively correlated with Northern Hemisphere temperature trends, and more strongly with a local, ∼600 yr long tree ring width chronology. Varve thickness increases in warm summers because of higher melt, runoff, and sediment transport (as expected), but also because shrinkage of the glacier dam allows shoreline regression that concentrates sediment in the smaller lake. Varve thickness provides a sensitive record of relative changes in warm season temperatures. Relative to the entire record, temperatures implied by this chronology were lowest around A.D. 600, warm between A.D. 1000 and A.D. 1300, cooler between A.D. 1500 and A.D. 1850, and have increased dramatically since then. Combined with stratigraphic evidence that contemporary jökulhlaups (which began in 1999) are unprecedented since at least A.D. 442, this record suggests that 20th century warming is more intense, and accompanied by more extensive glacier retreat, than the Medieval Warm Period or any other time in the last 1500 yr.

Paleolimnological techniques were used to identify environmental changes in and around Lake Dudinghausen (northern Germany) over the past 4800 yr. Diatom-inferred total phosphorus (DI-TP) changes identify four phases of high nutrient levels (2600–2200 BC, 1050–700 BC, 500 BC–AD 100 and AD 1850–1970). During these high DI-TP phases, fossil pollen, sediment geochemistry and archaeological records indicate human activities in the lake catchment. Although the same paleo-indicators suggest increased human settlement and agriculture activity during the late Slavonic Age, the Medieval Time and the Modern Time (AD 1000–1850), DI-TP levels were low during this period. In the sediments, iron and total phosphorus were high from ∼AD 100 to 1850, likely due to increased inflow of iron-rich groundwater into the lake. Increased iron input would have lead to a simultaneous binding and precipitation of phosphate in the upper sediment and overlying water column. As a result, anthropogenic impact on Lake Dudinghausen was masked by these phosphorus-controlling processes from AD 1000 to 1850 and was not evident by means of DI-TP. In accordance with fossil pollen, sediment geochemistry and limited archaeological records, DI-TP levels were low from AD 100–1000. Groundwater levels likely rose during this period as the climate gradually changed toward colder and/or moister conditions. Such climate change likely led to reduced settlement activities and forest regeneration in the catchment area. Our results are concordant with similar studies from central Europe which indicate rapid decreasing settlement activities from AD 100 to 1000.

Palynological, sedimentological and stable isotopic analyses of carbonates and organic matter performed on the El Portalet sequence (1802 m a.s.l., 42°48′00ʺN, 0°23′52ʺW) reflect the paleoclimatic evolution and vegetation history in the central-western Spanish Pyrenees over the last 30,000 yr, and provide a high-resolution record for the late glacial period. Our results confirm previous observations that deglaciation occurred earlier in the Pyrenees than in northern European and Alpine sites and point to a glacial readvance from 22,500 to 18,000 cal yr BP, coinciding with the global last glacial maximum. The patterns shown by the new, high-resolution pollen data from this continental sequence, chronologically constrained by 13 AMS 14C dates, seem to correlate with the rapid climate changes recorded in Greenland ice cores during the last glacial–interglacial transition. Abrupt events observed in northern latitudes (Heinrich events 3 to 1, Oldest and Older Dryas stades, Intra-Allerød Cold Period, and 8200 cal yr BP event) were also identified for the first time in a lacustrine sequence from the central-western Pyrenees as cold and arid periods. The coherent response of the vegetation and the lake system to abrupt climate changes implies an efficient translation of climate variability from the North Atlantic to mid latitudes.

The mid-Holocene (ca. 8000–4000 cal yr BP) was a time of marked aridity throughout much of Minnesota, and the changes due to mid-Holocene aridity are seen as an analog for future responses to global warming. In this study, we compare the transition into (ca. 9000–7000 yr ago) and out of (ca. 5000–2500 yr ago) the mid-Holocene (MH) period at Kimble Pond and Sharkey Lake, located along the prairie forest ecotone in south-central Minnesota, using high resolution (∼ 5–36 yr) sampling of pollen, charcoal, sediment magnetic and loss-on-ignition properties. Changes in vegetation were asymmetrical with increasing aridity being marked by a pronounced shift from woodland/forest-dominated landscape to a more open mix of grassland and woodland/savanna. In contrast, at the end of the MH, grassland remained an important component of the landscape despite increasing effective moisture, and high charcoal influxes (median 2.7–4.0 vs. 0.6–1.7 mm2 cm− 2 yr− 1 at start of MH) suggest the role of fire in limiting woodland expansion. Asymmetric vegetation responses, variation among and within proxies, and the near-absence of fire today suggest caution in using changes associated with mid-Holocene aridity at the prairie forest boundary as an analog for future responses to global warming.

Remains of a Holocene drowned forest in southern Lake Huron discovered in 12.5 m of water (164 m above sea level), 4.5 km east of Lexington, Michigan USA (Sanilac site), provided wood to investigate environment and lake history using several proxies. Macrofossil evidence indicates a forest comprised primarily of conifers equivalent to the modern “rich conifer swamp” community, despite generally low regional abundance of these species in pollen records. Ages range from 7095 ± 50 to 6420 ± 70 14C yr BP, but the clustering of stump dates and the development of 2 floating tree-ring chronologies suggest a briefer forest interval of no more than c. 400 years. Dendrochronological analysis indicates an environment with high inter-annual climate variability. Stable-carbon isotope composition falls within the range of modern trees from this region, but the stable-oxygen composition is consistent with warmer conditions than today. Both our tree-ring and isotope data provide support for a warmer environment in this region, consistent with a mid-Holocene thermal maximum. This drowned forest also provides a dated elevation in the Nipissing transgression at about 6420 14C yr BP (7350 cal yr BP) in the southern Lake Huron basin, a few hundred years before reopening of the St. Clair River drainage.

Establishing natural climate variability becomes particularly important in remote polar regions, especially when considering questions regarding higher than average warming. We present a high-resolution record of temperature variability for the past 800 yr based on sedimentary diatoms from a treeline lake in Finnish Lapland. The BSiZer multiscale smoothing technique is applied to the data to identify significant features in the record at different temporal levels. The overall reconstruction shows relatively large multi-centennial temperature variability with a total range of about 0.6–0.8°C. At millennial scales, the temperatures exhibit a statistically significant long-term cooling trend prior to industrialization (ΔT = −0.03°C/century). At the centennial timescale, three warm time intervals were identified around AD 1200–1300 (terminal phase of the Medieval Warm Period, MWP), 1380–1550 and from 1920 until the present. Pronounced coolness occurred between AD 1600 and 1920, indicative of the Little Ice Age (LIA). At the decadal level, certain shorter-term climate excursions were revealed. The warmest ∼10–30 yr, non-overlapping periods occurred in AD 1220–1250, 1470–1500 and 1970–2000, respectively. The classic events of MWP and LIA are evident in our record, as is also the 20th century warming.

Pollen, charcoal, magnetic susceptibility, and bulk density data provide the first paleoecological record spanning the last 33,000 years from the western cordillera of the Peruvian Andes. Sparse super-puna vegetation existed before 30,000 cal yr B.P. around Lake Compuerta (3950 m elevation), prior to a sedimentary hiatus that lasted until c. 16,200 cal yr B.P. When sedimentation resumed, a glacial foreland or super-puna flora is represented in which Polylepis was a significant element. Glacial outwash, marked by high sedimentary magnetic susceptibility, increased from c.16,200 cal yr B.P. and reached a peak at c. 13,200 cal yr B.P. Between c. 12,500 cal yr B.P. and 10,000 cal yr B.P., magnetic susceptibility was reduced. Vegetation shifts suggest a cool dry time, consistent with regional descriptions of the Younger Dryas event. Deglaciation resumes by 10,000 cal yr B.P. and the last ice is lost from the catchment at ∼7500 cal yr B.P. During the early Holocene warm and dry period between 10,000 and 5500 cal yr B.P., Alnus expanded in downslope forests. Alnus declined in abundance at 5500 cal yr B.P. when wetter and cooler conditions returned and human activity intensified. Maize (Zea mays) pollen first occurred in the core at ∼2600 cal yr B.P., indicating a minimum age for local agriculture. An increase in Alnus pollen abundance at ∼1000 cal yr B.P. could be due to human activity or perhaps due to a regional climate change associated with cultural turnover elsewhere in the Andes at this time.

The Great Sand Dunes National Park and Preserve (GSDNPP) in the San Luis Valley, Colorado, contains a variety of eolian landforms that reflect Holocene drought variability. The most spectacular is a dune mass banked against the Sangre de Cristo Mountains, which is fronted by an extensive sand sheet with stabilized parabolic dunes. Stratigraphic exposures of parabolic dunes and associated luminescence dating of quartz grains by single-aliquot regeneration (SAR) protocols indicate eolian deposition of unknown magnitude occurred ca. 1290–940, 715 ± 80, 320 ± 30, and 200–120 yr ago and in the 20th century. There are 11 drought intervals inferred from the tree-ring record in the past 1300 yr at GSDNPP potentially associated with dune movement, though only five eolian depositional events are currently recognized in the stratigraphic record. There is evidence for eolian transport associated with dune movement in the 13th century, which may coincide with the “Great Drought”, a 26-yr-long dry interval identified in the tree ring record, and associated with migration of Anasazi people from the Four Corners areas to wetter areas in southern New Mexico. This nascent chronology indicates that the transport of eolian sand across San Luis Valley was episodic in the late Holocene with appreciable dune migration in the 8th, 10–13th, and 19th centuries, which ultimately nourished the dune mass against the Sangre de Cristo Mountains.

Cosmogenic nuclide concentrations measured on abandoned fan surfaces along the Mojave section of the San Andreas Fault suggest that sediment is generated, transported, and removed from the fans on the order of 30–40 kyr. We measured in situ produced cosmogenic 10Be, and in some cases 26Al, in boulders (n = 15), surface sediment (n = 15), and one depth profile (n = 9). Nuclide concentrations in surface sediments and boulders underestimate fan ages, suggesting that 10Be accumulation is largely controlled by the geomorphic processes that operate on the surfaces of the fans and not by their ages.

Field observations, grain-size distribution, and cosmogenic nuclide data suggest that over time, boulders weather into grus and the bar sediments diffuse into the adjacent swales. As fans grow older the relief between bars and swales decreases, the sediment transport rate from bars to swales decreases, and the surface processes that erode the fan become uniform over the entire fan surface. The nuclide data therefore suggest that, over time, the difference in 10Be concentration between bars and swales increases to a maximum until the topographic relief between bars and swales is minimized, resulting in a common surface lowering rate and common 10Be concentrations across the fan. During this phase, the entire fan is lowered homogeneously at a rate of 10–15 mm kyr−1.

The field properties, micromorphology, grain-size, geochemistry, and optically stimulated luminescence (OSL) ages of two late Quaternary sections have been used to reconstruct the sequence of pedosedimentary processes and to provide insights into landscape evolution in part of the Northern Pampa of Argentina. Paleosols developed in paludal sediments adjacent to the Paraná river at Baradero and in loess at Lozada can both be correlated and linked to other sites, thus enabling for the first time the tentative recognition and tracing of a diachronous soil stratigraphic unit that probably spans the equivalent of at least part of marine oxygen isotope stage (OIS) 5. The paleosol at Lozada was truncated and buried beneath fluvial sediments during the time span of OIS 4 and 3. Eolian gradually replaced paludal inputs at Baradero over this period, and there were also two clearly defined breaks in sedimentation and development of paleosols. The period corresponding to OIS 2 was marked by significant loess accumulation at both sites with accretion continuing into the mid-Holocene only at Lozada. The more developed nature of the surface soil at Baradero probably reflects a combination of a moister climate and a longer soil-forming interval.

A 13.94-m-long sediment core, collected from a medium-sized lake in the Qilian Mountains (NE Tibetan Plateau, China), was analysed palynologically at 81 horizons. The interpretation of indicator taxa yielded various vertical shifts of the vegetation belts. These palaeovegetation results have been checked with lake surface pollen spectra from 8 lakes representing different altitudinal vegetation belts. Our main findings are the following: A short period of the late Marine Isotope Stage 3 (around ∼46,000 yr ago) was characterized by interglacial temperature conditions with a tree line above its present-day altitude. During the LGM, the vicinity of the lake was not covered by ice but by sparse alpine vegetation and alpine deserts, indicating that the climate was colder by ∼4–7°C than today. Markedly higher temperatures were inferred from higher arboreal pollen frequencies between ∼13,000 and ∼7,000 yr ago with a Holocene temperature optimum and a maximal Picea–Betula mixed-forest expansion between ∼9,000 and ∼7000 yr ago, when temperatures exceeded the present-day conditions by at least 1–2°C. Alpine steppes and meadows and sub-alpine shrub vegetation dominated around the lake since the middle Holocene, suggesting that vegetation and climate conditions were exceptionally stable in comparison to previous periods.

Perennially frozen loess deposits in the Klondike goldfields include paleosols formed in full-glacial environments, correlated by Alaskan distal tephra with Marine Isotope Stages (MIS) 2 and 4. Patterns of organic and inorganic carbon and clay distribution, microstructures, and profile morphologies indicate that soil formation occurred in a base-rich environment in which organic matter accreted predominantly as root detritus. At sites approximately 20 km apart, the expression of cryoturbation and ice wedge development decreases in strength upward in loess–paleosol sequences correlated with MIS 4, suggesting increasing aridity. Configurations of cryoturbation features and ice-wedge thaw unconformities, the presence of numerous ground squirrel burrows, and an absence of peat accumulation suggest that these substrates were predominantly well-drained, with active layers of equal or greater thickness than in modern soils on similar sites in the west-central Yukon. Some characteristics of these paleosols are similar to those of modern steppe and tundra soils, consistent with plant macrofossil evidence for local ecological diversity during full-glacial conditions in eastern Beringia.

Lake sediment cores from the Coast Mountains of British Columbia were analyzed using chemical sequential extractions to partition the dominant geochemical fractions of phosphorus (P). The P fractions include mineral P (the original source of bioavailable P), occluded P (bound to soil oxides), and organic P (remains of organic matter). By comparing P fractions of soil and recent lake sediment samples, these fractions are shown to be a valid proxy for landscape-scale nutrient status. Changes in soil development for an alpine watershed (Lower Joffre Lake) are inferred from the P fractions in the basin's outlet lake sediments. Glacially sourced mineral P dominates at the base of the core, but several rapid shifts in P geochemistry are evident in the first ∼3000 yr of the record. The latter indicates an interval of early and rapid soil nutrient maturation from ∼9600 to 8500 cal yr BP and a significant influx of slope-derived material into Lower Joffre Lake. A substantial increase in mineral P occurs at ca. 8200 cal yr BP, consistent with the cold event in the vicinity of the North Atlantic at that time. The more recent record reveals a continual increase in the proportion of mineral P from glacial sources to the lake, indicating a trend toward cooler conditions in the Coast Mountains.

Calcitic flowstones are present in fractures of a Pleistocene breccia near Innsbruck, Austria, and record periods of carbonate precipitation in the unsaturated zone between 101,500 ± 1500 and 70,300 ± 1800 yr, constrained by U-series disequilibrium dates. The occurrence of these speleothems, their low carbon isotopic composition, and the lack of infiltrated siliciclastic material demonstrate that the central Inn valley – which harbored one of the most extensive valley glaciers during the last glacial maximum – was ice-free during Marine Isotope Stages 5c to 5a. Climatically warm periods are separated by distinct drops in the oxygen isotopic composition of the speleothem calcite, attributed to strong and possibly seasonally biased atmospheric cooling. During these intervening stadials, which mirror those identified in the Greenland ice cores and marine sea-surface temperature records, calcite deposition apparently came to a halt, but the Inn Valley remained ice-free. The youngest calcite layer formed between ∼74,000 and ∼70,000 yr and places a maximum age limit on the likely expansion of alpine glaciers during the Marine Isotope Stage 5/4 transition, consistent with other speleothem records.

Lake Tyrrell is the largest playa in the Murray Basin of southeast Australia. Optical dating of transverse dune (lunette) sediments extends the lake's radiocarbon chronology to the last interglacial period. The highest lake level was attained 131,000 ± 10,000 yr ago, forming Lake Chillingollah, a megalake that persisted until around 77,000 ± 4000 yr ago. Pedogenesis of its sandy lunette continued until buried by a silty clay lunette deflated from the lake floor 27,000 ± 2000 yr ago. The dated soil-stratigraphic units correlate with the upper Tyrrell Beds and contain evidence that humans visited the lakeshore before 27,000 yr ago. The Lake Chillingollah megalake was synchronous with very high lake levels in monsoon-dominated Australia, yet it was not influenced by tropical monsoon systems. It was filled instead by increased winter rainfall from westerly low-pressure fronts. Greater effective precipitation across Australia is evident, the result of a weakened subtropical high-pressure zone.