High-resolution Chirp sub-bottom data were obtained offshore from the Northern Channel Islands (NCI), California, to image submerged paleoshorelines and assess local uplift rates. Although modern bathymetry is often used for modeling paleoshorelines, Chirp data image paleoshorelines buried beneath sediment that obscures their seafloor expression. The NCI were a unified landmass during the last glacial maximum (LGM; ~20 ka), when eustatic sea level was ~120 m lower than present. We identified seven paleoshorelines, ranging from ~28 to 104 m in depth, across this now-submerged LGM platform. Paleoshoreline depths were compared to local sea-level curves to estimate ages, which suggest that some were reoccupied over multiple sea-level cycles. Additionally, previous studies determined conflicting uplift rates for the NCI, ranging from 0.16 to 1.5 m/ka. Our results suggest that a rate on the lower end of this range better fits the observed submerged paleoshorelines. Using the uplift rate of ~0.16 m/ka, we estimate that paleoshorelines formed during Marine Oxygen Isotope Stage 3, the LGM, and the Younger Dryas stade are preserved on the NCI platform. These results help clarify uplift rates for the NCI and illustrate the importance of sub-bottom data for mapping submerged paleoshorelines.

Clay minerals from the Indus Canyon and eastern clinoform since ~12 ka are uniformly rich in smectite and illite, similar to those from the Holocene Indus flood plains. A systematic enrichment of smectite in the proximal delta compared to the canyon and eastern clinoform argues for preferential capture of smectite close to the river mouth since ~12 ka. There is a rapid shift to a more smectite-rich assemblage in the canyon and eastern clinoform after ~5 ka. This change is probably caused by a change in sediment source, with less direct flux from the Himalaya and more erosion of older, weathered, smectite-rich sediment from the Indus River flood plains, driven by incision of the Indus and its tributaries into the floodplain as summer monsoon rains weakened. This influx of smectite is consistent with lower kaolinite/smectite values since ~5 ka. The onset of large-scale agricultural activities since ~5 ka, especially starting with the Harappan Civilization, may also have enhanced incision and erosion of floodplain sediments over the same time period. This study reports for the first time how monsoon strength variations since ~12 ka affected the clay mineral assemblages and sediment provenance in a major submarine canyon.

A 328.58 m drill core (XK12) was recovered from lacustrine–alluvial sediments in the Xingkai Basin, northeast China, with the aim of obtaining a high-resolution pollen record of East Asian winter monsoon (EAWM) evolution since 3.6 Ma. An index based on the pollen record of thermophilous trees and terrestrial herbs is used as an indicator of winter temperature conditions controlled by the EAWM, at the glacial–interglacial scale. Primary age control was established based on lithostratigraphy and magnetostratigraphy, and then the pollen index was correlated to the LR04 global benthic δ18O record and finally tuned to Earth orbital obliquity to produce a high-resolution astronomical time scale. The pollen record indicates that the EAWM underwent two stepwise enhancements at 2.8 and 1.6 Ma. These events are consistent with paleoclimatic records of mean quartz grain size from the Chinese Loess Plateau, and they are also in accord with the initiation and intensification of Northern Hemisphere glaciation. Our findings suggest that the variability of the EAWM since 3.6 Ma was primarily controlled by changes in global ice volume and climatic cooling.

Multi-proxy analyses of a sequence spanning the Younger Dryas (YD) in the Glacial Lake Hind basin of Manitoba provides insight into regional paleohydrology and paleovegetation of meltwater rivers and lakes spanning >4000 yr; the sequence is controlled by 25 new accelerator mass spectrometry ages. This lake, dammed by the Laurentide Ice Sheet, overflowed into Lake Agassiz. The pre-YD interval records rapid sedimentation from meltwaters that headed in proglacial lakes in the Canadian Prairies that are known to have been catastrophically released when ice or sediment barriers were breached. Pollen in this phase is dominated by pre-Quaternary forms eroded from Paleocene bedrock. At the onset of the YD at ~12.8 cal ka, the sudden appearance of concentrations of nanodiamonds, high-temperature magnetic spherules, platinum, and iridium provide evidence of an extraterrestrial (ET) event that others have identified at more than 40 sites in North America. Major changes in oceans and climate, and the catastrophic outflow of nearby Lake Agassiz at the onset of the YD, may be related. Lower water levels and a reduction of Souris River inflow to Lake Hind followed, which are reflected by more clayey and organic-rich sediments and a decrease in pre-Quaternary palynomorphs. This may have resulted from the deepening of river valleys caused by the release of meltwater triggered by the ET event. Wetlands then began to develop, leading to peat deposition from 12.3 to 11 cal ka. This was followed by a fluvial episode depositing sand and then by increased Holocene aridity that resulted in accumulation of a thick sequence of dune sands. A dry woodland environment with a mix of conifers (especially Picea and Larix) and deciduous trees (especially Populus and Quercus) covered the uplands from ~13 to 10 cal ka.

Pressurised meltwater has a major impact on ice dynamics, as well as on sedimentary and deformational processes occurring below/in front of glaciers and ice sheets, but its role in glaciotectonic processes is yet to be fully understood. This study explores micro- and macroscale structures developed within décollements in two thrust-block moraines of Late Weichselian age in Melasveit, western Iceland. The aim is to investigate how pressurised subglacial meltwater can aid the dislocation and transport of large, unfrozen and unlithified sediment blocks by glaciers. A detailed model is constructed for the development of the thrust-block moraines and the microscale processes occurring along their detachments during thrusting. The detachments are characterized by relatively thin zones of crosscutting hydrofractures, which reflect fluctuating water pressures during glaciotectonism. Little evidence of shearing is observed along the leading edges of the thrusts in both moraines. This is supported by high water pressures along the detachments and indicates that the thrust blocks were initially decoupled from the underlying deposits. As the thrust moraines evolved, an increased amount of shear occurred in between events of sediment liquefaction, hydrofracturing, and fluid escape. This was followed by progressive locking up of the detachments and eventual cessation in the accretion of the thrust blocks.

The White Sea being connected with the Arctic Ocean via the Barents Sea has an influence on its water temperature/salinity structures and biological processes and thus has an indirect impact on the Eurasian climate system. In this work, we have managed to find a correspondence between the climate fluctuation in the Holocene and changes in the geochemical and microfossil properties in the sediment core of the White Sea. For the first time, the element speciation in the sediment core covering about 10,000 cal yr BP period was investigated. The cooling periods (the early Holocene and the Subboreal stage) were characterized by a trend of increase in Si, Al, and Ti contents and Ti/Al ratios, which reflect lithogenous contribution, and decrease in geochemically labile forms of trace elements. A significant increase in the content of organic-bound trace elements and biogenic components (Сorg, BSi, and chlorin) was observed during periods of Holocene climatic optimums. The evident relationship between the metal speciation and indicators of the sedimentation paleoenvironment is observed at the stage of the active phase of early diagenesis after the slowing down of the biogeochemical processes. Down-core decrease in the Mn oxyhydroxide content exhibited a weakening of diagenesis processes at the ~130–150 cm depth.

The thick sedimentary deposits of the Jiudong subbasin in the western Hexi Corridor of NW China can potentially provide important records of climate change in arid and semiarid areas subject to the interaction of the East Asian summer monsoon (EASM) and the westerlies. Here we present the results of a study of the clay mineralogy of the sediments of drill core DWJ from the Jiudong subbasin. The clay minerals consist mainly of illite, followed by chlorite, kaolinite, and smectite. The clay mineral assemblages are used to define four paleoclimatic stages since ~1.8 Ma: (1) During ~1.8–1.2 Ma, the climate was relatively cold and arid; (2) during ~1.2–0.9 Ma, it was relatively warm and wet, with strongly seasonal precipitation; (3) during ~0.9–0.3 Ma, there was a long-term trend of cooling and drying; and (4) during ~0.3–0.1 Ma, the climate was warmer and wetter than during the previous period, with strongly seasonal precipitation. The paleoclimatic record of the Jiudong subbasin since ~1.8 Ma is consistent with records from the Tengger Desert and typical monsoonal areas. This suggests that the EASM penetrated into the central regions of the North Qilian Shan and Zhangye–Jiudong subbasin during ~1.2–0.9 and ~0.3–0.1 Ma.

Stratigraphic records extending to Marine Oxygen Isotope Stage (MIS) 3 (57,000–29,000 cal yr BP) or older in Beringia are extremely rare. Three stratigraphic sections in interior western Alaska show near continuous sedimentological and environmental progressions extending from at least MIS 3, if not older, through MIS 1 (14,000 cal yr BP–present). The Kolmakof, Sue Creek, and VABM (vertical angle bench mark) Kuskokwim sections along the central Kuskokwim River, once a highland landscape at the fringe of central and eastern Beringia, contain aeolian deposition and soil sequences dating beyond 50,000 14C yr BP. Thick peaty soil, shallow lacustrine, and tephra deposits represent the MIS 3 interstade (or older). Sand sheet and loess deposits, wedge cast development, and very thin soil development mark the later MIS 3 period and the transition into the MIS 2 stade (29,000–14,000 cal yr BP). Loess accumulation with thicker soil development occurred between ~16,000–13,500 cal yr BP at the MIS 2 and MIS 1 transition. After ~13,500 cal yr BP, loess accumulation waned and peat development increased throughout MIS 1. These stratigraphic sequences represent transitions between a warm and moist period during MIS 3, to a cooler and more arid period during MIS 2, then a return to warmer and moister climates in MIS 1.

The Ceprano human calvarium, dated around 400,000 yr, is a well-known fossil specimen. It represents significant evidence of hominin presence in the Italian peninsula during the Middle Pleistocene and may be considered representative of an archaic variant of the widespread and polymorphic species Homo heidelbergensis. Since its discovery (March 1994), systematic surveys in the Campogrande area near Ceprano, central Italy, identified 12 localities (CG1-12) with archaeological and/or paleontological assemblages. On this basis, fieldwork was carried out at Campogrande between 2001 and 2006, including drilled cores and excavations, allowing a detailed description of the stratigraphic and paleoenvironmental context associated with the human fossil specimen and the archaeological materials. In the present paper we focus on the stratigraphy and sedimentological features of the uppermost deposits, coupled with a detailed appraisal of the available lithic assemblages that mostly belongs to overlying sediments (CG9 and CG10 localities). We conclude that the Ceprano hominin died in a floodplain environment with a low topographic gradient, where a fluvial meandering channel occurred. The archaeological materials describe a network of sites that document common behavioural features of human groups of the mid-to-late Middle Pleistocene, representing evidence of the regionalization observed across Europe after Marine Oxygen Isotope Stage 12.

Non-pollen palynomorphs and elemental geochemistry data from Lake Kifuruka in western Uganda provide evidence of environmental change in the tropical African region since the beginning of the Holocene. The multi-proxy record presented here shows that dry conditions dominated the end of the Pleistocene evidenced by calcium enriched sediments and suppressed fungal taxa activity. Moist conditions dominated the early Holocene and persisted until just after 1960 cal yr BP. Elevated frequencies of individual fungal spore taxa associated with herbivory and soil erosion, including Sordaria-type, Sporormiella-type, Chaetomium-type, and Glomus-type, about 4300 cal yr BP suggests a significant environmental change that could be linked to human activities. A convergence of multiple proxy data, including microscopic charcoal, elemental geochemistry, and fungal spores, strongly support the occurrence of anthropogenic forest disturbance in the Albertine Rift about 4300 cal yr BP.

A new fossil site in a previously unexplored part of western Madagascar (the Beanka Protected Area) has yielded remains of many recently extinct vertebrates, including giant lemurs (Babakotia radofilai, Palaeopropithecus kelyus, Pachylemur sp., and Archaeolemur edwardsi), carnivores (Cryptoprocta spelea), the aardvark-like Plesiorycteropus sp., and giant ground cuckoos (Coua). Many of these represent considerable range extensions. Extant species that were extirpated from the region (e.g., Prolemur simus) are also present. Calibrated radiocarbon ages for 10 bones from extinct primates span the last three millennia. The largely undisturbed taphonomy of bone deposits supports the interpretation that many specimens fell in from a rock ledge above the entrance. Some primates and other mammals may have been prey items of avian predators, but human predation is also evident. Strontium isotope ratios (87Sr/86Sr) suggest that fossils were local to the area. Pottery sherds and bones of extinct and extant vertebrates with cut and chop marks indicate human activity in previous centuries. Scarcity of charcoal and human artifacts suggests only occasional visitation to the site by humans. The fossil assemblage from this site is unusual in that, while it contains many sloth lemurs, it lacks ratites, hippopotami, and crocodiles typical of nearly all other Holocene subfossil sites on Madagascar.

The Bolivian Chiquitano dry forest is the largest block of intact seasonally dry tropical forest in South America and is a priority ecoregion for conservation due to its high threat status. However, the long-term impacts of drier climatic conditions on tropical dry forests are not well understood, despite climate models predicting increased droughts over Bolivia in the coming century. In this paper, we assess the impacts of drier climatic conditions during the mid-Holocene on the Bolivian Chiquitano tropical dry forest using fossilised pollen, phytoliths, macro-charcoal, and geochemical proxies from a sediment core from a large lake (Laguna Mandioré) on the Bolivia–Brazil border. Our results show that drier climatic conditions during the mid-Holocene caused a local-scale, ecotonal expansion of upland savannah at the expense of dry forest. Interaction between drier climatic conditions and fire regime likely exerted a stronger control over the position of the dry forest–savannah ecotone than edaphic factors. However, the majority of the dry forest within the lake catchment maintained a closed canopy throughout the drier conditions of the mid-Holocene, despite floristic turnover towards more drought-tolerant taxa. These findings imply overall resilience of the Chiquitano dry forest biome to future drought, albeit with floristic changes and upland savannah encroachment at ecotones.

During the Pleistocene in the northern part of Europe and Asia, the presence of ice sheets not only limited the range of species but also influenced landscape and thus the contemporary habitat system that determines the pattern of biodiversity. The aim of the research was to find out whether and how a lowland landscape, which formed as a result of subsequent Pleistocene glaciations (five) that in Eurasia covered various and generally successively smaller areas, affected the genetic differentiation of a species. The research was carried out in eastern Poland on the root vole Microtus oeconomus (Arvicolinae, Rodentia), a model boreal and hygrophilous species. Samples were collected from 549 vole individuals at 33 locations. Based on the analysis of 12 microsatellite loci and the 908 bp of cytochrome b sequences (mitochondrial DNA), the genetic structure of M. oeconomus in the landscape zones of the Polish Lowlands was determined. The results show that the latitudinal variability of the relief in eastern Poland (resulting from different ranges of Pleistocene ice sheets) and the related specific configuration of hydrogenic habitats are reflected in the genetic differentiation of the root vole. Therefore, it may be concluded that the history of landscape development affects the genetic structure of hydrophilic species.

Wildfires are sensitive to climate change, but their response to changes in temperature and precipitation on long timescales is still disputed. In this study, we present a ~9.4 ka black carbon mass sedimentation rate (BCMSR) record from Lake Ximenglongtan (XMLT), southwestern China, to elucidate the Holocene fire regime and its linkages to climatic conditions. The results indicate that the regional fire activity was low during the early Holocene (before 7.6 cal ka BP), increased notably at 7.6 cal ka BP, and continued to increase gradually during the mid- to late Holocene until 2.2 ka. The episodes of higher fire occurrence reflected by higher BCMSR over the last 2.2 ka might be more likely related to the intensified human activities. The cool and humid climate during the early Holocene limited the spread of fire, while warming and drying at ~7.6 cal ka BP triggered higher fire occurrence. Instead of temperature, changes in precipitation dominated fire regime variation during the mid- to late Holocene. On millennial timescales, we suggest that Holocene fire variability has been predominantly controlled by the combined effects of Northern Hemisphere (NH) summer and winter insolation that influenced monsoonal precipitation and fire season temperature, respectively. Indian Ocean Dipole (IOD) events may also have affected fire incidence through influencing monsoon intensity.

Quaternary processes and environmental changes are often difficult to assess in remote subantarctic islands due to high surface erosion rates and overprinting of sedimentary products in locations that can be a challenge to access. We present a set of high-resolution, multichannel seismic lines and complementary multibeam bathymetry collected off the eastern (leeward) side of the subantarctic Auckland Islands, about 465 km south of New Zealand's South Island. These data constrain the erosive and depositional history of the island group, and they reveal an extensive system of sediment-filled valleys that extend offshore to depths that exceed glacial low-stand sea level. Although shallow, marine, U-shaped valleys and moraines are imaged, the rugged offshore geomorphology of the paleovalley floors and the stratigraphy of infill sediments suggests that the valley floors were shaped by submarine fluvial erosion, and subsequently filled by lacustrine, fjord, and fluvial sedimentary processes.

Archive color photographs—particularly of sites where sediment is no longer available—are an underused resource that potentially contains detailed paleoenvironmental information. To investigate this potential, two sets of digital images were taken, at different times, of loess, glaciolacustrine, and deep-sea sediments. The first image set was taken using standard digital cameras. Lighting conditions and sediment surface preparation varied, in a similar way to characteristics likely to be encountered in archive photographs. The second image set was taken by a high-resolution, line-scan camera with an integrated light source. CIELAB (Commission Internationale de l'Eclairage) color reflectance data were obtained from both image sets and analyzed by cross correlation. Of the three reflectance parameters (L*, a*, and b*), L* reflectance is the most compromised by differences in ambient lighting or moisture content. Textural distinctions appear to be an important factor influencing the cross correlations and produce multiple, relatively weak solutions for the glaciolacustrine sediments, whereas the texturally uniform loess and deep-sea sediments produce a single, best-fit solution. Comparison of a* reflectance records from an undated marine sequence with a chronologically constrained sequence from the same site indicates the potential to apply color reflectance to produce preliminary age models.

We reconstructed the late Holocene relative sea-level (RSL) evolution of the ancient harbour of Naples, one of the largest coastal conurbations in the Mediterranean. We carried out multiproxy investigations, coupling archaeological evidence with biological indicators. Our data robustly constrain 2000 yr of non-monotonic changes in sea level, chiefly controlled by the complex volcano-tectonic processes that characterize the area. Between ~200 BC and AD ~0, a subsidence rate of more than ~1.5 mm/yr enhanced the postglacial RSL rise, while negligible or moderate land uplift < ~0.5 mm/yr triggered a RSL stabilization during the Roman period (first five centuries AD). This stabilization was followed by a post-Roman enhancement of the sea-level rise when ground motion was negative, attested by a subsidence rate of ~0.5 to ~1 mm/yr. Our analysis seems to indicate very minor impacts of this nonmonotonic RSL evolution on the activities of the ancient harbour of Naples, which peaked from the third century BC to the second century AD. After this period, the progressive silting of the harbour basin made it impossible to safely navigate within the basin, leading to the progressive decline of the harbour.

The sedimentological and geochemical characteristics of sediments from Lake Szurpiły (northeastern Poland) can be used as a record of mass movement and climate dynamics since the Allerød. Late-glacial sediments suggest enhanced runoff conditions in the catchment after the retreat of the Scandinavian Ice Sheet, while Holocene varved sediments are interrupted by mass-movement deposits (MMDs). We identified 85 thin (<10 cm) MMDs (type 1) that consist of autochthonous material and frequently occur during the Atlantic period. Mobilization of littoral zone and slope sediments caused redeposition in the deepest part of the lake and was likely related to climatic conditions. In contrasting, one sedimentary unit (>1-m-thick MMD type 2) consists of auto- and allochthonous material and represents multistage processes, including erosion and deformation of underlying varved sediments, rapid deposition of clastic material, and redeposition of previously eroded varved sediments. Seismic activity or permafrost degradation was responsible for the deposition of MMD type 2. Furthermore, varve-thickness variability suggests Gleissberg and Suess solar cycles before 850 BC, when human impact was limited. Additionally, 22 and 11 yr sunspot cycles are recognized in light/dark laminae-thickness ratios and reflect influences of solar irradiance on lacustrine productivity.

Multiproxy analysis of two sediment cores recovered from lagos Morrenas 3C and Ditkebi, located in the páramo of Costa Rica's Chirripó National Park, was undertaken to develop multidecadal-scale reconstructions of late Holocene fire regimes for the region. Analysis of macroscopic charcoal and sediment geochemistry (C%, N%, δ13C, δ15N, and C/N ratios) documents periodic burning of the páramo in Chirripó National Park during the past ~1700 yr. The charcoal records provide evidence of high fire frequency between AD ~560 and 720 and between AD ~980 and 1230. Severe fire episodes are reflected by a rapid increase in the flux of carbon (C) and nitrogen (N) from the surrounding catchment because of the volatilization of páramo vegetation. Additionally, δ15N, which sharply increases following local fire events, captures postfire changes in nutrient loading and, likely, the decadal-scale rate of postfire recovery of páramo vegetation. The consistently high δ13C and C/N values observed between AD ~700 and 1100 suggest an expansion of Muhlenbergia, a native C4 grass growing near shore, suggesting that the interval between AD ~700 and 1100, broadly corresponding to the Terminal Classic Drought and Medieval Climate Anomaly, was characterized by a decrease in effective moisture and temperature.