The popular technique of estimating ages of deposits from sizes of lichens continues despite valid criticism, and without agreement on range of utility, treatment of error, and methods of measurement, sampling, and data handling. A major source of error is the assumption that the largest lichen(s) colonized soon after deposition and will survive indefinitely. Recent studies on lichen mortality suggest that this assumption is untenable. Meanwhile, the use of “growth curves” constructed from independently dated substrates is problematic for many reasons, but this has not prevented the publication of baseless claims of accuracy and ages that are extrapolated well beyond data. Experiments indicate that numeric lichenometric ages are not reliable, and in general do not advance the cause of Quaternary science. There are a few studies suggesting reliability, and indeed there may be cases where lichens and growth curves actually provide realistic numerical ages. But it cannot be foretold which lichen assemblages will provide good ages and which bad ages. The logical conclusion is that no assumption of good ages can be made, and that it is folly to assign numerical ages to a deposit on the basis of lichen sizes.

Investigations of the relationships between climate and human history often place more emphasis on the science of climate change than on understanding human socio-economic processes, and therefore suffer from superficial results and an unbalanced perspective. This is partly due to the lack of high-resolution data concerning long-term socio-economic processes. Here, we base our study of climate and society on a series of 2130-yr-long economic proxy data from China with decadal resolution. The economy was associated significantly with temperature and precipitation at the two predominant bands of 100 and 320 yr. The phase transition of economic states was influenced positively by long-term temperature change combined with triggering effects of short-term changes in precipitation. However, climatic impact on economy should not be recognized as simple causality but some driving-response relation coupled with meditation by human agency at multiple scales. A model of ‘adaptive cycles’ implies, in relative to the developing phases, climate–economy relationship during the declining phases was more easily moderated by slower processes like rigidity and faster processes like unrest. From a more-macro perspective, climatic driving for the macro-economic cycles was moderated by larger and slower processes like social memory, spatial shifting of key economic areas, and social–technical advance.

A multidisciplinary study from a number of drilled cores in the Guadalquivir estuary has made possible to identify as many as three extreme wave events and their facies in the 4th millennium BP (A: ~ 4000 cal yr BP, B: ~ 3550 cal yr BP, and C: ~ 3150 cal yr BP). These events, which caused strong erosion in the Guadalquivir sandy barrier and in the neighboring aeolian systems of El Abalario, brought about significant paleogeographical changes that may have affected human settlements established in the area during the Neolithic and Copper Age periods and during the Middle Bronze Age. The three events can be spatially correlated and their facies differentiated from more proximal to more distal from the coastline. The most proximal facies is characterized by a massive accumulation of shells, a sandy or sandy–muddy matrix, an erosive base, a highly diverse mixture of species (marine and estuarine), and lithoclasts. The most distal facies presents a muddy–sandy matrix, dominance of estuarine fauna, shell accumulation, presence of terrestrial species, mudpebbles, pebbles in a clayey matrix, and bioturbation. The evidence presented will further advance scientific knowledge about the impact of extreme wave events on coastal areas in SW Iberia and NW Africa.

Salt-marsh sediments provide accurate and precise reconstructions of late Holocene relative sea-level changes. However, compaction of salt-marsh stratigraphies can cause post-depositional lowering (PDL) of the samples used to reconstruct sea level, creating an estimation of former sea level that is too low and a rate of rise that is too great. We estimated the contribution of compaction to late Holocene sea-level trends reconstructed at Tump Point, North Carolina, USA. We used a geotechnical model that was empirically calibrated by performing tests on surface sediments from modern depositional environments analogous to those encountered in the sediment core. The model generated depth-specific estimates of PDL, allowing samples to be returned to their depositional altitudes. After removing an estimate of land-level change, error-in-variables changepoint analysis of the decompacted and original sea-level reconstructions identified three trends. Compaction did not generate artificial sea-level trends and cannot be invoked as a causal mechanism for the features in the Tump Point record. The maximum relative contribution of compaction to reconstructed sea-level change was 12%. The decompacted sea-level record shows 1.71 mm yr− 1 of rise since AD 1845.

The northern portion of the coastal plain of the Rio Grande do Sul State (southernmost Brazil) comprises an outer sandy barrier that protects a complex lagoon system formed during the Holocene. The terraces of three different lagoons (Gentil, Malvas and Pinguela) formed along their margins record the depositional processes and the relative base level changes over the past 5000 yr. Therefore, our main objective was to characterize and quantify base level fluctuations from the study of these terraces, to correlate them to sea-level changes and to describe the depositional architecture related to the distinct sea-level stages (high-resolution sequence stratigraphy). Satellite images, topographic and GPR profiles, auger holes and radiometric dating were used. The main results indicate a close relationship between relative base level and relative sea-level changes, a stillstand period just after the last transgressive maximum (4840–4650 cal yr BP) and a subsequent overall relative sea-level fall of about 3 m. Both a normal (highstand systems tract) and a forced regression (falling-stage systems tract) controlled the geological record preserved in the terraces. The highstand (older terrace) is characterized by agradational bedding, whereas the falling stage comprises three progradational sets (terraces) bounded by erosive surfaces related to smaller-scale sea-level drops.

We present a shoreline-based, millennial-scale record of lake-level changes spanning 12.8–2.3 ka for a large closed-basin lake system on the southwestern Tibetan Plateau. Fifty-three radiocarbon and eight U–Th series ages of tufa and beach cement provide age control on paleoshorelines ringing the basin, supplemented by nineteen ages from shell and aquatic plant material from natural exposures generally recording lake regressions. Our results show that paleo-Ngangla Ring Tso exceeded modern lake level (4727 m asl) continuously between ~ 12.8 and 2.3 ka. The lake was at its highstand 135 m (4862 m asl) above the modern lake from 10.3 ka to 8.6 ka. This is similar to other closed-basin lakes in western Tibet, and coincides with peak Northern Hemisphere summer insolation and peak Indian Summer Monsoon intensity. The lake experienced a series of millennial-scale oscillations centered on 11.5, 10.8, 8.3, 5.9 and 3.6 ka, consistent with weak monsoon events in proxy records of the Indian Summer Monsoon. It is unclear whether these events were forced by North Atlantic or Indian Ocean conditions, but based on the abrupt lake-level regressions recorded for Ngangla Ring Tso, they resulted in significant periodic reductions in rainfall over the western Tibetan Plateau throughout the Holocene.

14C dating of shoreline deposits of closed-basin lake Baqan Tso in the western Tibetan Plateau shows that lake level regressed from the undated highstand (46 m above modern, 4.3 × modern surface area) of likely earliest Holocene age by 11.5 ka, and remained larger than modern until at least ≈ 5.0 ka. The shoreline record broadly matches other regional climate records, with lake level closely following Northern Hemisphere summer insolation overprinted by sub-millennial lake-level oscillations. A model coupling modern land runoff and lake surface heat closely reproduces estimated modern precipitation of ≈ 240 mm/yr. We estimate that the Baqan Tso basin required ≈ 380 mm/yr precipitation to sustain the maximum early Holocene lake area, a 55% increase over modern. Precipitation increases, not glacial meltwater, drove lake-level changes, as Baqan Tso basin was not glaciated during the Holocene. Our estimate assumes early Holocene insolation (≈ 1.3% overall increase), and mean annual increases of 2°C in temperature, and 37% in relative humidity. We additionally developed a Holocene precipitation history for Baqan Tso using dated paleolake areas. Using the modern and early Holocene model results as end-members, we estimate precipitation in the western Tibetan Plateau which was 300–380 mm/yr between 5.0 and 11.5 ka, with error of ± 29–57 mm/yr (± 12–15%).

The main objective of this study is to document paleofire activity during the late-glacial/early-Holocene transition in temperate ecosystems. For this purpose, we cored lakes Paladru and Moras (Rhone valley, France) and quantified sedimentary charcoal accumulation rate and fire frequency. To assess the role of climate and vegetation in paleofire activity, charcoal data were compared to vegetation dynamics based on pollen analyses and to climate reconstructions. The first increase in paleofire activity occurred at the beginning of the Bølling/Allerød Interstadial period (14,500 cal yr BP), synchronous with temperature and fire-prone vegetation increases. During the Younger Dryas, paleofire activity first decreased (12,600–12,200 cal yr BP) and then abruptly increased (12,200–11,600 cal yr BP). This change corresponds to a known climate partitioning that occurred during the Younger Dryas and implies that a sufficient quantity of biomass was available during the second period. At the beginning of the Holocene, fire activity remained high. This is in agreement with the increases in temperature and vegetation density. The change in forest composition since ca. 11,200 cal yr BP partly explains the decrease in paleofire activity, whereas warm climate conditions seem suitable for fire ignition and propagation.

The isotopic composition of Sr and Nd and elemental concentrations (e.g., Na, K, Ca, Mg, Al) of three primary Negev loess sequences trace the relative contributions of desert dust sources over the past ~180,000 yr to the southeastern Mediterranean. We focused on the geochemical signature of the fine (<20 μm) and coarse (>20 μm) grain-size modes of the loess to identify their respective provenances. The isotopic composition of the coarse fraction falls on a mixing line of sources feeding the Nile and its delta. The chemical compositions of the coarse fraction and the Sinai–Negev sand dunes are similar, indicating that this fraction is the product of aeolian abrasion of the adjacent Sinai–Negev sands. In turn, these sands are derived from the Nile delta and transported inland. The fine fraction has less negative εNd values and slightly deviates from the mixing line, indicating an additional end-member. The higher εNd values and Mg/Al ratios of the fine fraction are relatively well correlated (R2 = 0.64) and point to Arabian dust as an additional source. Temporal changes in the geochemical composition of loess over time reflect changes in climates of source areas and the Eastern Mediterranean. Shifts from Saharan to Arabian fine dust-dominated intervals indicate wetter conditions in the southern Sahara that weaken dust fluxes from this source relative to the Arabian fluxes.

We investigate the distribution of archaeal lipids in a 5.8-m-long sedimentary core recovered from Lake Qinghai to extract regional hydroclimate and temperature signals since the last deglaciation for this important region. The paleohydrology was reconstructed from the relative abundance of thaumarchaeol (%thaum) and the archaeol and caldarchaeol ecometric (ACE) index. The %thaum-inferred lake-level record was extended to deglaciation, showing three periods (11.9–13.0, 14.1–14.7 and 15.1–17.2 cal ka BP) with relatively higher lake levels than those during the early Holocene. The ACE record demonstrates three periods (10.6–11.2, 13.2–13.4 and 17.4–17.6 cal ka BP) of elevated salinity when the lake was shallow. Filtered TEX86 record based on archaeal lipid distributions corresponded to relatively higher lake levels, implying that a certain lake size is required for using the TEX86 paleothermometer. At 1–4 cal ka BP, the reconstructed temperature fluctuated significantly and correlated negatively with inferred lake level, indicating that lake temperature and hydrological change might be coupled during this period. We attribute this co-variance to the importance of summer temperature in controlling evaporation for this arid/semi-arid region. Moreover, our results indicate that archaeal lipids have potential in reconstructing paleoclimate patterns from lacustrine sedimentary cores, but the data should be interpreted with care.

Since the mid-19th century, western Oregon's Willamette Valley has been a source of remains from a wide variety of extinct megafauna. Few of these have been previously described or dated, but new chronologic and isotopic analyses in conjunction with updated evaluations of stratigraphic context provide substantial new information on the species present, timing of losses, and paleoenvironmental conditions. Using subfossil material from the northern valley, we use AMS radiocarbon dating, stable isotope (δ13C and δ15N) analyses, and taxonomic dietary specialization and habitat preferences to reconstruct environments and to develop a local chronology of events that we then compare with continental and regional archaeological and paleoenvironmental data. Analysis of twelve bone specimens demonstrates the presence of bison, mammoth, horse, sloth, and mastodon from ~ 15,000–13,000 cal yr BP. The latest ages coincide with changing regional climate corresponding to the onset of the Younger Dryas. It is suggested that cooling conditions led to increased forest cover, and along with river aggradation, reduced the area of preferred habitat for the larger bodied herbivores, which contributed to the demise of local megafauna. Archaeological evidence for megafauna–human interactions in the Pacific Northwest is scarce, limiting our ability to address the human role in causing extinction.

The lake-level variations during the Late Glacial in the Lake Karakul basin (a closed glacierized-basin), in the northernmost part of the eastern Pamirs, were reconstructed using geomorphological and sedimentological evidence, with a chronology developed using luminescence ages from sand-sized quartz and K-feldspar in the lake sediments. Lake transgression started before ~ 19 ka, with the peak water level of ~ 35 m above the present elevation occurring at ~ 15 ka. This was synchronous with a significant advance of the glacier in the catchment. Stepwise lake regression, including a rapid lowering of the lake level (~ 13 m at ~ 12 ka), persisted until at least ~ 10 ka. Lake transgression and localized glacier expansion from ~ 19 to ~ 15 ka likely correlate with the more regional Late Glacial glacier advances across the semi-arid western Himalayan–Tibetan orogen and the eastern Pamirs. The longer-term trend of this lake transgression was probably caused by colder and/or wetter climatic conditions, forcing a notable glacier advance.

The terminal lake systems of central Australia are key sites for the reconstruction of late Quaternary paleoenvironments. Paleoshoreline deposits around these lakes reflect repeated lake filling episodes and such landforms have enabled the establishment of a luminescence-based chronology for filling events in previous studies. Here we present a detailed documentation of the morphology and chemistry of soils developed in four well-preserved beach ridges of late Pleistocene and mid-to-late Holocene age at Lake Callabonna to assess changes in dominant pedogenic processes. All soil profiles contain evidence for the incorporation of eolian-derived material, likely via the formation of desert pavements and vesicular horizons, and limited illuviation due to generally shallow wetting fronts. Even though soil properties in the four studied profiles also provide examples of parent material influence or site-specific processes related to the geomorphic setting, there is an overall trend of increasing enrichment of eolian-derived material since at least ~ 33 ka. Compared to the Holocene profiles, the derived average accumulation rates for the late Pleistocene profiles are significantly lower and may suggest that soils record important regional changes in paleoenvironments and dust dynamics related to shifts in the Southern Hemisphere westerlies.

Repeated outburst flooding from glacial Lake Missoula, Montana, affected large areas of Washington during Marine Oxygen Isotope Stage 2 (29–14 ka). We present the first high-resolution rock magnetic results from two sites that are critical to interpreting these outburst floods and that provide evidence of sediment provenance: glacial Lake Missoula, the source of the floods; and glacial Lake Columbia, where floodwaters interrupted sedimentation. Magnetic carriers in glacial Lake Missoula varves are dominated by hematite, whereas those in outburst flood sediments and glacial Lake Columbia sediments are mainly magnetite and titano-magnetite. Stratigraphic variation of magnetic parameters is consistent with changes in lithology. Importantly, magnetic properties highlight depositional processes in the flood sediments that are not evident in the field. In glacial Lake Columbia, hematite is present in fine silt and clay deposited near the end of each flood as fine sediment settled out of the water column. This signal is only present at the end of the floods because the hematite is concentrated in the finer-grained sediment transported from the floor of glacial Lake Missoula, the only possible source of hematite, ~ 240 km away.

Large alluvial fans characterize the piedmonts of the White Mountains, California–Nevada, USA, with large boulders strewn across their surfaces. The boulders are interpreted as flash floods deposits with an unclear trigger for the transport process. Several triggers are possible, including glacial lake outburst floods (GLOFs), thunderstorms or rainfall on snow cover. From a paleoenvironmental perspective, the origin of the flash floods is of fundamental importance. The alluvial fans that flank the White Mountains at Leidy Creek display particularly impressive examples of these deposits. The boulder deposits and the source catchment at Leidy Creek were examined using 10Be terrestrial cosmogenic nuclide (TCN) surface exposure dating to help elucidate their age and origin. All boulders dated on the alluvial fans date to the Holocene. This is in accordance with the geomorphic analyses of the Leidy Creek catchment and its terraces and sediment ridges, which were also dated to the Holocene using optically stimulated luminescence (OSL) and 10Be surface exposure. The results suggest that the boulders on the alluvial fan were deposited by flash floods during thunderstorm events affecting the catchment of the Leidy Creek valley. Paleomonsoonal-induced mid-Holocene flash floods are the most plausible explanation for the discharges needed for these boulder aggradations, but a regional dataset is needed to confirm this explanation.

An outcrop-based lake-level curve, constrained by ~ 70 calibrated 14C ages on Anodonta shells, indicates at least 8 highstands between 45 and 25 cal ka BP within 10 m of the 543-m upper threshold of Lake Manix in the Mojave Desert of southern California. Correlations of Manix highstands with ice, marine, and speleothem records suggest that at least the youngest three highstands coincide with Dansgaard–Oeschger (D–O) stadials and Heinrich events 3 and 4. The lake-level record is consistent with results from speleothem studies in the Southwest that indicate cool wet conditions during D–O stadials. Notably, highstands between 43 and 25 ka apparently occurred at times of generally low levels of pluvial lakes farther north as interpreted from core-based proxies. Mojave lakes may have been supported by tropical moisture sources during oxygen-isotope stage 3, perhaps controlled by southerly deflection of Pacific storm tracks due to weakening of the sea-surface temperature gradient in response to North Atlantic climate perturbations.

The depositional history of the lower Yangtze River and sea-level changes during Marine Oxygen Isotope Stage (MIS) 3 was established using three long drill cores from the northern Yangtze deltaic plain and southern Yellow Sea by using sedimentary analysis and AMS 14C dates. Voluminous channel deposits of the lower Yangtze River in MIS 3 were found from the northern deltaic plain and offshore area, with a thickness of over 30 m. The thick channel deposits are characterized by massive medium-to-fine sand deposits with sporadic tidal influence. During MIS 3, the Yangtze River appears to have mainly migrated between the modern river mouth and middle Jiangsu coastal plain, and likely built a delta complex in the field of Yangtze Sand Shoal in northern East China Sea. A large sediment supply and rapid sea-level variations promoted rapid progradation of the delta onto the flat shelf. The highest sea levels during MIS 3 are estimated to have reached 25 ± 5 m below the present sea level.

The architecture of coastal sequences in tectonically-active regions results mostly from a combination of sea-level and land-level changes. The objective of this study is to unravel these signals by combining sequence stratigraphy and sedimentology of near-shore sedimentary sequences in wave-built terraces. We focus on Santa María Island at the south-central Chile margin, which hosts excellent exposures of coastal sediments from Marine Isotope Stage 3. A novel method based on statistical analysis of grain-size distributions coupled with facies descriptions provided a detailed account of transgressive–regressive cycles. Radiocarbon ages from paleosols constrain the chronology between > 53 and ~ 31 cal ka BP. Because the influence of glaciations can be neglected, we calculated relative sea-level curves by tying the onset of deposition on a bedrock abrasion platform to a global sea-level curve. The observed depositional cycles match those predicted for uplift rates between 1.2 and 1.8 m/ka. The studied sedimentary units represent depositional cycles that resulted in reoccupation events of an existing marine terrace. Our study demonstrates wave-built marine terrace deposits along clastic shorelines in temperate regions can be used to distinguish between tectonic uplift and climate-induced sea-level changes.

Results of stratigraphic and morphotectonic analyses on fluvial terraces at the outlet of the Meduna valley in the eastern Southern Alps are used to investigate on the tectonics and paleoclimate. The Meduna valley, prone to destructive earthquakes, belongs to the front of the eastern Southern Alps, a south-verging fold and thrust belt in evolution from the Middle Miocene to the present, constructed by ENE–WSW striking, SSE-verging medium to low-angle thrusts, gradually propagating in the Venetian–Friulian plain. In the study area, located south of the Periadriatic thrust, the main structural element is the ENE–WSW striking Maniago–M. Jouf thrust system. Seven depositional units, ranging in age from Pliocene to Holocene, and a hierarchy of four numbered terrace complexes were identified. Stratigraphic and geometric relationships between sedimentary units, basal surfaces and terraces allow the reconstruction of the chronology of the depositional events. The study shows that the valley configuration has been shaped during the Pliocene–Quaternary with long-lasting steady intervals, interspaced with periodic tectonic pulses of the thrust front of the eastern Southern Alps. The most recent pulse related to the Maniago thrust shows an upper Pleistocene–Holocene slip rate of about 0.6 mm/yr.