The appearances of palaeosurfaces intercalated into palaeo-dune fields on Fuerteventura are multifaceted. Although reddened layers in these dune sediments might suggest that strong soil-formation processes have taken place, the combination of aridity and parent material, namely biogenic carbonate sand of shelf origin, reveals that strong soil formation seems unlikely. These sediments rather represent de- and recalcification processes only. Solely in the case of admixed material of volcanic origin and dust deposits further soil-forming processes seem to be possible. Hematite-rich Saharan dust contributes to reddish colouration of the palaeosurfaces. In addition, CaCO3-coated iron particles appear to be ingredients of dust being leached after deposition and transformed to hematite. Overall, we propose much weaker soil-forming processes during the Pleistocene than previously postulated. Our findings support the relevance of local environments. Carbonate sands of shelf origin hinder strong soil formation and the reddish layers separating dune generations are palaeosurfaces, which mainly consist of Saharan dust. After deposition of allochthonous material, these layers are overprinted by weak soil-forming processes. The formation of palaeosurfaces primarily depends on morphodynamically stable periods during limited sand supply. Our data suggest a cyclicity of processes in the following order: (1) sand accumulation, (2) dust accumulation and weak soil formation, and (3) water-induced erosion. For the Canary Islands, we support the assumption of glacial maxima being periods of increased levels of moisture. In combination with rising sea level, we propose that favorable conditions of surface stability occur immediately after glacial maxima during periods of starting transgression, whereas regression periods immediately after sea-level high stands seem to yield the highest sand supply for the study area.

Different interpretations of accumulation and preservation of aeolian sediments lead to divergent and sometimes contradictory palaeoclimate reconstructions. Although aeolian transport mainly occurs during dry climate, the preservation of the aeolian sediment is a critical factor in many environments in determining the nature of the aeolian sedimentary archive. Analysis of more than 200 optically stimulated luminescence ages for aeolian sands from Tibet shows four different aeolian phases of accumulation. Strong aeolian activity occurred during the last glacial maximum, but hardly any aeolian sediments are preserved. Consequently, the period with the highest aeolian activity is not recorded in the sedimentary record. A phase of aeolian accumulation occurred in the late glacial and the early Holocene. The duration of deposition for this phase is a consequence of the complex topography and an increase in moisture. This phase was punctuated by exceptionally strong accumulation during the Younger Dryas stade. The mid-Holocene is characterised by weak aeolian accumulation and fluvial erosion caused by greater precipitation during the maximum height of the Asian summer monsoon. Aeolian activity resumed in the late Holocene because of drier conditions. The conceptual model provides an approach that can be applied to other mountain and desert margin regions that have limited sediment availability.

The island of Gran Canaria is regularly affected by dust falls due to its proximity to the Saharan desert. Climatic oscillations may affect the Saharan dust input to the island. Geochemical, mineralogical, and textural analysis was performed on a well-developed and representative early Pleistocene paleosol to examine Saharan dust contribution to Gran Canaria. Significant and variable Saharan dust content was identified in addition to weathering products such as iron oxides and clay minerals. Variations in quartz and iron oxide concentrations in the paleosol likely reflect different Saharan dust input in more/less-contrasted rhexistasic/biostatic climatic conditions. Linking the quartz content in Canarian soils, the Ingenio paleosol, and two Canarian loess-like deposits to different ages from the Quaternary, we hypothesized that the dust input should be lower (about 33–38%) throughout the early to middle Pleistocene than during the late Quaternary. The Saharan dust input to the Gran Canaria profile in the Pleistocene persisted in spite of climatic variations.

One of the enduring questions in the field of paleohydrology is how quickly desert wetland ecosystems responded to past episodes of abrupt climate change. Recent investigations in the Las Vegas Valley of southern Nevada have revealed that wetlands expanded and contracted on millennial and sub-millennial timescales in response to changes in climate during the late Quaternary. Here, we evaluate geologic evidence from multiple localities in the Mojave Desert and southern Great Basin that suggests the response of wetland systems to climate change is even faster, occurring at centennial, and possibly decadal, timescales. Paleowetland deposits at Dove Springs Wash, Mesquite Springs, and Little Dixie Wash, California, contain evidence of multiple wet and dry cycles in the form of organic-rich black mats, representing periods of past groundwater discharge and wet conditions, interbedded with colluvial, alluvial, and aeolian sediments, each representing dry conditions. Many of these wet-dry cycles date to within the Younger Dryas (YD) chronozone (12.9–11.7 ka), marking the first time intra-YD hydrologic variability has been documented in paleowetland deposits. Our results illustrate that desert wetland ecosystems are exceptionally sensitive to climate change and respond to climatic perturbations on timescales that are relevant to human society.

A key concern regarding current and future climate change is the possibility of sustained droughts that can have profound impacts on societies. As such, multiple paleoclimatic proxies are needed to identify megadroughts, the synoptic climatology responsible for these droughts, and their impacts on past and future societies. In the hyperarid Atacama Desert of northern Chile, many streams are characterized by perennial flow and support dense in-stream wetlands. These streams possess sequences of wetland deposits as fluvial terraces that record past changes in the water table. We mapped and radiocarbon dated a well-preserved sequence of in-stream wetland deposits along a 4.3-km reach of the Río San Salvador in the Calama basin to determine the relationship between regional climate change and the incision of in-stream wetlands. The Río San Salvador supported dense wetlands from 11.1 to 9.8, 6.4 to 3.5, 2.8 to 1.3, and 1.0 to 0.5 ka and incised at the end of each of these intervals. Comparison with other in-stream wetland sequences in the Atacama Desert, and with regional paleoclimatic archives, indicates that in-stream wetlands responded similarly to climatic changes by incising during periods of extended drought at ~9.8, 3.5, 1.3, and 0.5 ka.

We developed a 1108 yr chronology of tree-ring widths, based on 64 Himalayan pencil juniper (Juniperus semiglobosa Regel) trees, for the Pamir-Alay Mountains, central Asia. Dendroclimatological analysis demonstrates that precipitation has significant effects on tree growth in the semiarid mountainous area of northwestern Tajikistan located on the edge of the great midlatitude Karakum and Kyzylkum deserts. The highest level of linear correlation (r=0.67) is observed between tree growth and seasonalised winter (previous December–February) precipitation. Our studies also show that moisture (precipitation/Palmer Drought Severity Index) from the previous June to the current September was the dominant climatic factor accounting for interannual variations in tree-ring width, suggesting that this should be considered in climate reconstruction. Using the transfer function method, we reconstructed the region’s drought history over the period AD 908–2015. The results of this moisture reconstruction showed that the most recent millennium was characterised by series of dry and wet stages. The driest periods occurred before 1000, 1200–1250, and at the end of the eighteenth century and beginning of the nineteenth century. The wettest conditions existed in 1650–1700 and after 1990.

The multi-layered settlement of Turganik in the Tok River valley (steppe region west of the Urals) has been studied using paleopedological and microbiomorphical methods. Early humans lived in the settlement during the Eneolithic epoch (the fifth millennium BC) and in the Early Bronze Age (the fourth millennium BC). The cultural layers attributable to the Atlantic period of the Holocene developed under conditions of a rather dry climate, with the landscapes being dominated by the grass and herb steppe. The settlement area was above the flood water level and was suitable for habitation. The soils in its vicinity were Kastanozems (Endosalic Protosodic). The final stages of the cultural layer formation bear traces of strong (though short-term) floods, with the deposits of the latter partly concealed traces of the preceding long-term arid phase. Maximum aridity was during the final interval of the Atlantic period. The Subboreal and Subatlantic periods were noted for meadow-chernozem soil formation (Luvic Chernozems [Stagnic]) and an increasing proportion of arboreal species in the pollen assemblages. Some phytoliths of aquatic plants were found in the assemblages dominated by those of meadow grasses. The climate was more humid and cool, although short episodes of aridity were possible.

Large changes in landscape, vegetation, and culture in northwestern (NW) Europe during the first millennium AD seem concurrent with climatic shifts. Understanding of this relation requires high-resolution palaeoclimate reconstructions. Therefore, we compiled available climate reconstructions from sites across NW Europe (extent research area: 10°W–20°E, 45°–60°N) through review of literature and the underlying data, to identify supraregional climatic changes in this region. All reconstructions cover the period from AD 1 to 1000 and have a temporal resolution of ≤50 yr. This resulted in 22 climate reconstructions/proxy records based on different palaeoclimate archives: chironomids (1), pollen (6), Sphagnum mosses (1), stalagmites (8), testate amoebae (4), and tree rings (2). Comparing all temperature reconstructions, we conclude that summer temperatures between AD 1 and 250 were relatively high, and the period between AD 250 and 700 was characterised by colder summer conditions. The period from AD 700 to 1000 was again characterised by warmer summers. These temperature shifts occurred in the whole of NW Europe. In contrast, the compilation of precipitation reconstructions does not show a common pattern across NW Europe either as a result of a heterogeneous precipitation pattern or the lack of suitable and consistent precipitation proxies.

The subantarctic island of South Georgia provides terrestrial and coastal marine records of climate variability, which are crucial for the understanding of the drivers of Holocene climate changes in the subantarctic region. Here we investigate a sediment core (Co1305) from a coastal inlet on South Georgia using elemental, lipid biomarker, diatom, and stable isotope data to infer changes in environmental conditions and to constrain the timing of late-glacial and Holocene glacier fluctuations. Because of the scarcity of terrestrial macrofossils and the presence of redeposited and relict organic matter in the sediments, age control for the record was obtained by compound-specific radiocarbon dating of mostly marine-derived n-C16 fatty acids. A basal till layer recovered in Little Jason Lagoon was likely deposited during an advance of local glaciers during the Antarctic cold reversal. After glacier retreat, an oligotrophic lake occupied the site, which transitioned to a marine inlet around 8.0±0.9 ka because of relative sea-level rise. From 7.0±0.6 to 4.0±0.4 ka, reduced vegetation coverage in the catchment, as well as high siliciclastic input and deposition of ice-rafted debris, indicates glacier advances in the terrestrial catchment and likely in the adjacent fjord. A second, less extensive period of glacier advances occurred in the late Holocene, after 1.8±0.3 ka.

In the hinterland of the desert, valuable archives of paleoenvironmental evolution are scarce. Calcareous root tubes (CRTs) have a strong potential for reconstructing paleoenvironmental conditions. It is still unclear, however, whether chemical elements in the CRTs can provide insights into paleoenvironmental conditions. In this study, the major- and trace-element composition of 32 CRT samples from the Alashan Desert were analyzed by X-ray fluorescence spectrometry. Results showed that the elemental composition and content change were controlled by the parent material and climatic conditions at the time of CRT formation. Ca, Mg, and Sr were significantly affected by climate, whereas the enrichment of P is likely related to the growth of plants. Higher (lower) Mg/Ca and Sr/Ca ratios corresponded to higher (lower) effective moisture and a higher (lower) Mg/Sr ratio indicated a higher (lower) temperature during the middle Holocene (8–5 cal ka BP). The reconstruction results for effective moisture were consistent with those in the Asian monsoon margin of northwestern China, which were caused by higher monsoon precipitation and lower evaporation. Therefore, chemical elements in the CRTs can reflect changes in paleo-effective moisture and paleotemperature at a millennial resolution in this area.

High-resolution diatom stratigraphies from mid-Holocene sediments taken from fringe and central locations in Moss Lake, a small lake in the foothills of the Cascade Range, Washington, have been analyzed to investigate the impacts (and duration) of tephra deposition on the aquatic ecosystem. Up to 50 mm of tephra was deposited from the climactic eruption of Mount Mazama 7958–7795 cal yr BP, with coincident changes in the aquatic ecosystem. The diatom response from both cores indicates a change in habitat type following blanket tephra deposition, with a decline in tychoplanktonic Fragilaria brevistriata and Staurosira venter and epiphytic diatom taxa indicating a reduction in aquatic macrophyte abundance. Additionally, the central core shows an increase in tychoplanktonic Aulacoseira taxa, interpreted as a response to increased silica availability following tephra deposition. Partial redundancy analysis, however, provides only limited evidence of direct effects from the tephra deposition, and only from the central core, but significant effects from underlying environmental changes associated with climatic and lake development processes. The analyses highlight the importance of duplicate analyses (fringe and central cores) and vigorous statistical analyses for the robust evaluation of aquatic ecosystem change.

Ice-wedge activity can be used to reconstruct past environmental conditions. We investigated the moisture source and timing of ice-wedge formation on the Blackstone Plateau. A section of permafrost exposed ice wedges that developed at two distinct depths: the first set formed syngenetically and penetrated alluvial silts from the top of permafrost; the second set, truncated by an erosional or thaw contact, was found solely in icy muddy gravels (>3.1 m depth). The δ18O and D-excess records of the ice wedges suggest that they formed from freezing of snow meltwater whose isotopic composition evolved during meltout. The 14CDOC results suggest that climate was favorable to ice-wedge growth between 32,000–30,000 and 14,000–12,500 cal yr BP, but there was likely a hiatus during the last glacial maximum due to climate being too dry. During the early to mid-Holocene, ice wedges were inactive as a result of warmer and wetter climate. Ice wedge re-initiated around 6360 cal yr BP, with a peak in activity between 3980 and 920 cal yr BP, a period characterized by cool and moist climate. Overall, timing of ice-wedge activity was broadly consistent with the climate and vegetation evolution in the western Arctic.

The timing, structure, and landscape change during the Patagonian Ice Sheet deglaciation remains unresolved. In this article, we provide a geomorphic, stratigraphic, and geochronological deglacial record of Río Cisnes Glacier at 44°S and also from the nearby Río Ñirehuao and Río El Toqui valleys (45°S) in Chilean Patagonia. Our 14C, 10Be, and optically stimulated luminescence data indicate that after the last glacial maximum, Río Cisnes Glacier experienced ~100 km deglaciation between >19.0 and 12.3 ka, accompanied by the formation of large glacial paleolakes. Deglaciation was interrupted by several ice readvances, and by 16.9±0.3 ka, Río Cisnes Glacier extended only ~40% of its full glacial extent. The deglaciation of Río Cisnes Glacier and other sensitive Patagonian glaciers occurred at least 1 ka earlier than the ca. 17.8 ka normally assumed for the local termination, coincident with West Antarctic isotope records. This early deglaciation can be linked to an orbital forcing–driven decline of Southern Ocean sea ice associated with a distinct atmospheric warming that is apparent for West Antarctica through Patagonia.

Calcareous dust occurs in Argentina as layers and pockets closely associated with Pleistocene deposits and periglacial features from southernmost Patagonia to at least the Mendoza Precordillera and has been traditionally interpreted as a soil horizon resulting from postdepositional pedogenesis during interglacials. Detailed field and microscopic observations and sedimentological and geochemical analyses of more than 100 samples collected from lower to upper Pleistocene deposits between 51°S and 33°S and from near sea level to 2800 m asl allow us to interpret the dust as synchronous with the host sediment. All observations and analyses lead us to conclude that: (1) the cryogenic morphology and the chemical signatures of the calcite component show that the dust is glaciogenic, (2) the dust was carried by southeasterly Antarctic winds, and (3) it was deposited over most of southern and central Argentina. Field observations, geomorphic evidence, and radiocarbon dates suggest that the dust was deposited during several Pleistocene glacial episodes.

The Chaudière River region in the Appalachian Mountains of eastern Canada is approximately 700 km north of the southernmost Pleistocene glacial deposits in New York and New Jersey. Detailed compositional analyses of glacial and non-glacial sediments from stratigraphic exposures and more than 40 boreholes drilled to bedrock provide a compositionally constrained record of glacial events, which include deposits of one Marine Oxygen Isotope Stage (MIS) 6 and two post-MIS 5 glaciations. The glacial and associated proglacial deposits rest on compositionally distinctive, preglacial saprolite that is preserved in deeper valleys. These observations constrain interpretations of the glacial/Pleistocene history of the eastern United States and Canada. The fact that there is no unequivocal evidence of pre-MIS 6 till in the Chaudière River region, while there are well-documented pre-MIS 6 glacial deposits south of there and in the American Midwest, also has major climatic implications. The Laurentide Ice Sheet and its ancestors must have been more robust in the west in the early Pleistocene and in the east most recently.

The chronology of over 50 tephra layers preserved in a lake sediment core from Laguna La Trapananda (LLT) in the southern portion of the Andean Southern Volcanic Zone (SSVZ), Chile, is constrained by new radiocarbon age determinations, which span the period from late Pleistocene glacial retreat to the late Holocene. The tephra are correlative with tephra previously described from other lake cores in the region and are attributed to explosive eruptions of the SSVZ volcanoes Mentolat, Hudson, Macá, and potentially Cay. The new age determinations are used to estimate the ages of the >50 tephra in the LLT core, as well as those from the other previously described lake cores in the area, by a Bayesian statistical method. The results constrain the frequency of explosive eruptions of the volcanic centers in the southernmost SSVZ. They indicate that there was essentially no increase in the rate of eruptions from late-glacial to recent times due to deglaciation. They also provide isochrones used to constrain the depositional histories of the small lacustrine systems within which they were deposited and they provide a tephrochronologic tool for other paleoclimatic, paleoecologic, archaeologic and tephrochronologic studies in central Patagonia.

Highly resolved, well-dated paleoclimate records from the southern South African coast are needed to contextualize the evolution of the highly diverse extratropical plant communities of the Greater Cape Floristic Region (GCFR) and to assess the environmental impacts on early human hunter-gatherers. We present new speleothem stable oxygen and carbon isotope ratios (δ18Oc and δ13C) from two caves at Pinnacle Point, South Africa, covering the time between 330 and 43 ka. Composite δ18Oc and δ13C records were constructed for Staircase Cave and PP29 by combining all stable isotope analyses into a single time series and smoothing by a 3-point running mean. δ18Oc and δ13C values record changes in rainfall seasonality and the proportions of C3 and C4 plants in the vegetation, respectively. We show that in general increased summer rainfall brought about a wider spread of C4 grasses and retreat of the C3 plant–dominated GCFR communities. The occurrence of summer rainfall on the southern coast of South Africa was linked to total rainfall amounts in the interior region through tropical temperate troughs. These rainfall systems shifted the southern coastal climate toward more summer (winter) rainfall when precession was high (low) and/or the westerlies were in a northern (southern) position.

Climatic change that affects biological productivity is often argued to be a primary force influencing human activities during the glacial period. To test this assumption, we combine in-site pollen, paleoclimatic, and archaeological data from the Dadiwan site and nearby areas on the western Loess Plateau (WLP) that date to Marine Oxygen Isotope Stage (MIS) 3. Our comparison of multiple datasets suggests that regional human activities increased when the vegetation around the Dadiwan area shifted from forest steppe in the early MIS 3 (59–46.7 ka) to steppe in the middle to late MIS 3 (46.7–29.5 ka). Our results indicate that regional human activities increased again during the late MIS 3 when the amount of precipitation was higher, as indicated by the lower Artemisia proportion. We suggest that increased precipitation on the WLP enhanced the above-ground biomass production and may be responsible for an increase in human activity and population in this region.

The Brittany region of France is located in a low seismicity intraplate zone. Most of the instrumented earthquakes are limited to a shallow crustal depth without surface rupture. A paleoseismological analysis was performed on deposits on the Crozon Peninsula and in the Elorn estuary. We highlight hydroplastic deformations induced by liquefaction leading to clay diapirism, which were likely triggered by past earthquakes. This diapirism seems to be frequent in continental nonconsolidated sediments and to develop on the inherited tectonic structures, when a shallow water table and confining layers exist. Timing of deformation is dated using paleoenvironmental data, and electron spin resonance and infrared-stimulated luminescence dating methods. Two seismic periods were identified in western Europe during early Marine Oxygen Isotope Stage (MIS) 10 (~380 ka) and early MIS 8 (~280–265 ka). The lack of similar deformations affecting the Holocene tidal deposits in the Bay of Brest suggests that the magnitude of the triggering paleoearthquakes is probably higher (Mw ~6) than the recent events (Mw 5.4). These unusual intraplate major paleoearthquakes need specific factors affecting the far-field crustal stress loading to be triggered, such as a brief acceleration of the Africa-Eurasia lithospheric plate convergence, glacio-isostatic stress perturbations associated with the onset of major glaciations in northern Europe, or other processes induced by orbital forcing.