In humid, continental Michigan, we identified pedogenic carbonate in a soil profile developed on glacial drift sediments, as rinds, rhizoliths, and filaments (at depths >50 cm). Given that the climate setting is unusual for pedogenic carbonate, we investigated its formation with environmental monitoring and isotope analyses of carbonate (δ13C, δ18O, Δ47, and 14C) and waters (δ18O and δ2H). We found covariation in δ13C and Δ47 amongst the carbonate types (rhizoliths, rinds, filaments, bulk soil, and detrital clasts), and 14C ages of rinds that predate plausible formation ages. The δ13C and Δ47 values of the bulk carbonate and some of the pedogenic morphologies are not fully compatible with pedogenic formation in the modern environment. The δ18O data from precipitation and river waters and from carbonates are not uniquely identifying; they are compatible with the soil carbonate being pedogenic, detrital, or a mix. We conclude that the soil carbonate is likely a physical mix of pedogenic and detrital carbonate. Pedogenic carbonate is forming in this humid setting, likely because seasonal cycles in soil respiration and temperature cause cycles of dissolution and re-precipitation of detrital and pedogenic carbonate. The pedogenic carbonate may be a transient feature as carbonate-rich till undergoes post-glacial chemical weathering.

A continental-type glacial flood termed the Suwałki megafloods took place in NE Poland during the last glaciation and significantly transformed the proglacial area. This study aims, for the first time, to establish the chronology of this flood. Twenty-two sediment samples from two meltwater spillways were dated by optically stimulated luminescence. Sixteen ages from the flood megadunes are between 83 ± 11 ka and 16.9 ± 0.9 ka, whereas six ages from the outwash tracks range from 71.5 ± 9.9 ka to 20.3 ± 2.5 ka. Three dates from the uppermost part of the megadune sedimentary successions are 16.9 ± 0.9 ka, 17.9 ± 1.9 ka, and 18.8 ± 1.3 ka, and they may mark the likely true age of the Suwałki megafloods. We found no consistent relationships between the sedimentary structures and bleaching characteristics suggesting that the two are largely independent, contrary to what is typically assumed for fluvial deposits. Similarly, the transport distance from the ice margin did not exert a consistent influence on the sediment bleaching characteristics. A new hypothesis considers the stage of flooding to have a relevant impact on sediment bleaching: sediment deposited during the flood waning is well bleached and has a high potential for constraining the flood age.

The aardvark (Oryecteropus afer) is a fossorial species with a widespread distribution across sub-Saharan Africa. It leaves distinctive tracks and traces of its presence, including large burrows. However, despite a substantial body fossil record, few trace fossils registered by aardvarks have been described. Its distribution range in southern Africa during historic and prehistoric times was probably broadly similar to that of today, with the addition of the currently submerged Palaeo-Agulhas Plain during much of the Pleistocene. Five new trace fossil sites have been identified in Pleistocene aeolianites on the Cape coast and are here interpreted with varying degrees of confidence as large burrows that were made by aardvarks. In addition, a possible aardvark tracksite has been identified. Together these add to the sparse paleoichnological evidence of aardvarks and add to the global ichnological record of large vertebrate burrows. While at this point the evidence does not warrant the proposal of new ichnotaxa, the findings may act to spur further identification of fossilized traces of aardvarks and other fossorial species on the Cape coast and beyond.

The stratigraphic record of the Early Holocene in the Nebraska Sand Hills suggests dry climatic conditions and periods of sustained aeolian activity, which resulted in several well-documented instances of sand dunes blocking river drainages in the western Sand Hills. Here, we present evidence that drainage blockage by migrating sand dunes also occurred in the central Sand Hills, where precipitation is higher and dune morphology differs. The South Fork Dismal River valley contains a sequence of aeolian, alluvial, and lacustrine sediments that record a gradual rise of the local water table following a sand dune blockage of the river valley around 11,000 years ago. After the initial development of a wetland, a lake formed and persisted for at least 2000 years. Increased groundwater discharge due to a warm, moist climate in the region after 6500 years ago likely caused the breaching of the dune dam and eventually resulted in the decline of the local water table. Through a careful examination of the intricate relationships between ground water, surface water, and sand movement in a dune field setting, we discuss the hydrologic system's complex response to climate change. We use diatoms to reconstruct the lacustrine environment and optically stimulated luminescence and radiocarbon dating to provide chronological control, based on a careful evaluation of the strengths and limitations of each method in varied depositional environments.

Here we present the first high-resolution continuous palaeoecological study from Greece covering the Mesolithic–Neolithic transition at Limni Zazari, a small lake in western Macedonia. We study how interactions between vegetation and climate might have affected the introduction of agriculture to Europe ca. 8500 years ago. We found that mixed deciduous oak woodlands established around the lake once moisture availability began to increase at ~10,300 cal yr BP. Between 8600 and 8000 cal yr BP, climate change, causing drier conditions, led to the decline of the woodlands and the expansion of steppe and grassland vegetation. Concurrently, in agreement with the archaeological record, pollen indicative of arable and pastoral farming indicate the onset of Neolithic farming. After 8000 cal yr BP the forest composition changed, with a major expansion of pine forests and increases in disturbance-adapted trees like Ostrya and Fagus. This change might be linked to changes in moisture availability, but it is likely that land use also facilitated these shifts. We conclude that the introduction of Neolithic farming was advantaged by climate-induced vegetation changes. While the vegetation structure around Zazari was very sensitive to changes in moisture, early anthropogenic disturbances led to changes in the vegetation composition that are still important today.

Loess, a geologic record of dust, is an optimal archive for exploring paleoclimate and the paleo-dust path from source to sink. The dust path for the Songnen Plain, NE China, during the last glacial period has not been established. To address this, 63 surface sediment samples from the Northeast China Sandy Lands, i.e., Onqin Daga Sandy Land (OD), Horqin Sandy Land (HQ), Hulun Buir Sandy Land (HL), and Songnen Sandy Land (SN), and six samples from the last glacial loess in the Harbin area were collected for elemental geochemical analysis of the <10 μm fraction to quantitatively reconstruct the dust pathway using a frequentist model. The results show that these sandy lands have a distinct geochemical composition due to a control from markedly different provenances. The quantitative results indicate that the dust contribution of the southwestern SN to the Harbin loess is as high as 50.4–77.2%, followed by the OD and HQ (3.3–34.8%), the northwestern SN (0–36.8%), and the HL (0–8%). Notably, the dust contribution to the Harbin loess began to change considerably after ~46–41 ka BP, with a significant increase from 1.1% to 41.2% from the northwestern direction. Some ecological safety strategies are proposed to address dust pollution in the Harbin area.

Prehistoric humans seem to have preferred inhabiting small river basins, which were closer in distance to most settlements compared to larger rivers. The Holocene landscape evolution is considered to have played a pivotal role in shaping the spatiotemporal patterns of these settlements. In this study, we conducted comprehensive research on the relationship between landscape evolution and settlement distribution within the Huangshui River basin, which is a representative small river in Central China with numerous early settlements, including a prehistoric city known as the Wangjinglou site (WJL). Using geoarchaeological investigations, optically stimulated luminescence dating, pollen analysis, and grain-size analysis, we analyzed the characteristics of the Holocene environment. The results indicate the presence of two distinct geomorphic systems, namely the red clay hills and the river valley. The red clay hills, formed in the Neogene, represent remnants of the Songshan piedmont alluvial fan that was eroded by rivers. There are three grades of terraces within the river valley. T3 is a strath terrace and formed around 8.0 ka. Both T2 and T1 are fill terraces, which were developed around 4.0 ka and during the historical period, respectively. The sedimentary features and pollen analysis indicate the existence of an ancient lake-swamp on the platform during 11.0–9.0 ka. This waterbody gradually shrank during 9.0–8.0 ka, and ultimately disappeared after 8.0 ka. Since then, the development of large-scale areas of water ceased on the higher geomorphic units. River floods also cannot reach the top of these high geomorphic units, where numerous prehistoric settlements are located, including the Xia–Shang cities of the WJL site. Our research demonstrates that landscape stability supported the long-term and sustainable development of ancient cultures and facilitated the establishment of the WJL ancient cities in the region.

A paleomagnetic study of basaltic lava flows exposed in the northern Neuquén Cordillera, southernmost Central Andes, along the Antiñir-Copahue fault zone (ACFZ), involved 25 sites of the Cola de Zorro Formation (Pliocene–Early Pleistocene) along two different sections. The sites show exclusive normal polarity, corresponding to the Late Pliocene Gauss chron (3.6–2.6 Ma). The angular standard deviation of virtual geomagnetic poles (VGPs; ASD = 14.8°) is consistent with the expected values from recent geomagnetic models, in opposition to anomalously low dispersion found in previous studies in Pleistocene VGPs of reverse polarity from neighboring areas to our study zone. Mean paleomagnetic directions for Bella Vista (Dec = 0.0°, Inc = −50.0°, α₉₅ = 7.6°, K = 36.7, N = 11) and Río Huaraco sections (Dec = 354.9°, Inc = −57.0°, α₉₅ = 7.5°, K = 55.7, N = 8) do not show tectonic rotation around vertical axes. Combining and regrouping our and previous data by area confirmed the absence of tectonic rotations in the Huaraco-Trohunco block and a statistically significant clockwise rotation of 14.4° ± 10.3° of three adjacent tectonic blocks located south of our study locality in Pleistocene times. These results suggest that strike-slip deformation along some sections of the ACFZ was significant in the Pleistocene structural evolution of this region.

Significant thicknesses, a large number of paleosols, and an impressive chronological framework place the loess–paleosol series of the Afghan-Tajik depression on a par with the famous sections of the Chinese Loess Plateau. Based on the results of field stratigraphy, description of the macro- and micromorphological structure, field magnetic susceptibility measurements, and study of the chemical and grain-size compositions, a comprehensive characterization of the structure, properties, and formation conditions of paleosol horizons and loess layers was carried out. Three loess units and two pedocomplexes are distinguished in the late and upper middle Pleistocene deposits of the Obi-Mazar section. These sediments are characterized by high silt and carbonate content and the presence of loess with pedogenic features. Pedocomplex PC1, consisting of three paleosols, according to the stratigraphic position and absolute dating, corresponds to MIS 5. Pedocomplex PC2, consisting of two developed paleosols separated by loess, is correlated with MIS 7. The properties of the studied paleosols together with modern soil distribution in the region allow for the reconstruction of the soil type of PC1 and PC2 of the Obi-Mazar section with the genesis of the Calcisols–Kastanozems groups.

Recent research on the Bering Glacier forelands in the northern Gulf of Alaska provides new insights into late Pleistocene/early Holocene shorelines, providing a favorable route for human migration as early as ~16,000 cal yr BP. This route included an irregular coastline with embayments and islands offering protection from the open ocean; edible marine invertebrates dating from 15,000 to 5,500 cal yr BP; and marine vertebrates dating as early as 16,000 cal yr BP. The latter included walrus (Odobenus rosmarus), bearded seal (Erignathus barbatus), and ringed seal (Phoca cf. hispida), all associated with pack ice conditions unlike those present today. While this ecosystem could have supported humans migrating along the coastline, and coastal refugia may have existed elsewhere in the region, coastal archaeological sites in the northern Gulf of Alaska and southwest Alaska are no older than ~9,500 cal yr BP. This suggests that the earliest sites have been eroded or destroyed, that the earliest migrants ignored available marine resources, and/or that these migrants did not use a coastal route. In contrast, the earliest archaeological sites in southeast Alaska date to ~12,500 cal yr BP, suggesting migration from interior Alaska to the coast somewhere east of the Copper River delta.