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Simple Summary: One of the main differences between the modern fauna of steppe and desert-steppe insects and the similar fauna of the Last Ice Age is the current leading position of darkling beetles (Coleoptera, Tenebrionidae), which are represented in fossil faunas only by singletons. We hypothesize that the reason lies in the insufficient cold resistance of these insects for successful overwintering. We studied the cold resistance of adults from five species of darkling beetles from the Altai Mountains that overwinter in the soil and the larvae from one such species. The ranges of three of these are limited from the north by the desert-steppe margin of Central Asia with extremely low air temperatures. More than 50% of individuals of these species in the experiment did not withstand cooling below −22 °C. Temperatures in the soil of natural habitats at a depth of 10 cm are close to or lower than the above values. Overwintering is therefore possible in places with greater snow thickness (hollows, wind shade of shrubs and large cereals). Since darkling beetles are now on the border of temperature resistance in the Altai, they likely did not exist in the much more severe conditions of the glacial periods in the Altai Mountains, West Siberian Plain, and Northeast Asia. The level of diversity and abundance of darkling beetles (Coleoptera, Tenebrionidae) is the main difference between the late Pleistocene and modern insect faunas of arid regions. In the Pleistocene assemblages they are extremely rare, whereas in the modern ones they predominate. It is assumed that the reason for their rarity in fossil entomological complexes is their lack of cold resistance. The supercooling points (SCP) and low lethal temperatures (LLT) of adults from five species of Altai darkling beetles that overwinter in the soil and larvae from one such species were measured in the laboratory. All beetles supercooled at negative temperatures but could not survive freezing, with the average SCP of the most cold-resistant species between −25.7 and −21.7 °C (Bioramix picipes, Anatolica dashidorzsi, and Penthicus altaicus). However, 50% of the individuals from different species in the experiment died after exposure during two days at temperatures ranging from −22 to −20 °C. The focal species are distributed in parts of Central Asia with an extreme continental climate, and the temperatures measured in the soil of these natural areas turned out to be lower than or close to the limit of cold resistance of the beetles. Overwintering of darkling beetles is therefore only possible in areas with deep snow: in hollows, under bushes, and under large cereals. Darkling beetles with poor cold resistance could not have existed in the colder climate of the late Pleistocene, which explains their absence from fossil fauna. [ABSTRACT FROM AUTHOR]

China has the most numerous Danxia and Karst landscapes, which serve as special terrestrial islands harboring ample endemic species, though how did these endemic species spread among those isolated sites is still an unresolved issue. To address this question, we explored the phylogeographical structure and demographic history of Firmiana danxiaensis, a tree species endemic to Danxia and Karst landscapes. We collected 295 samples (28 populations) of F. danxiaensis. Plastid genomes were assembled for 25 representative samples. Sanger sequencing of four plastid regions and restriction‐site‐associated DNA sequencing were performed on the 28 populations. The phylogenetic tree constructed from plastid genomes and restriction site‐associated DNA sequencing (RAD‐seq) data supported that F. danxiaensis originated from Mount Danxia and Nanxiong Basin, spread to Karst landscapes near Yingde City, and then back to Danxia Mountain and the Nanxiong Basin. In the Nanxiong Basin, the latter arrivals captured the plastid of the former. Population analyses revealed strong population structure among and within Danxia and Karst landscapes, possibly due to low seed and pollen dispersal abilities of the species. The demographic and ecological niche modeling approaches suggested that F. danxiaensis have widely occurred in the southeast of China during the last glacial period, and later retreated to the cliffs of Danxia and Karst landscapes due to temperature rising and competition failure. The declining of the effective population size of the species throughout the postglacial period suggested that global warming, agriculture, and industrial civilizations could have affected the survival of this species, and more measures should be taken to conserve these species. [ABSTRACT FROM AUTHOR]

Precambrian tropical glaciations pose a significant challenge to our understanding of Earth's climate. A popular explanation invokes runaway ice-albedo feedback leading to "iceball earth", an extreme state conflicting however with the sedimentary evidence of an open ocean and active hydrological cycle. We point out flawed physics of the runaway scenario, which overlooks potency of the ocean heat transport in deterring the perennial sea ice. Nor is frozen ocean needed for tropical glaciation as the latter requires only that the tropical land be cooled to below the marking temperature of the glacial margin, which is necessarily above the freezing point to counter the yearly accumulation. Since tropical glaciations generally coincide with Precambrian supercontinents, we posit that it is their blockage of the brighter tropical sun that causes the required cooling. To test this hypothesis, we formulate a minimal two-box model, which is nonetheless thermodynamically closed and yields lowering tropical/polar temperatures with increasing tropical land, whose crossings of the glacial marking temperature would divide non/polar/pan-glacial regimes--the last being characterized by tropical glaciation abutting an open ocean. Given the observed chronology of paleogeography, our theory may provide a unified account of the faint-young-sun paradox, Precambrian tropical glaciations and glacio-epochs through Earth's history. [ABSTRACT FROM AUTHOR]

The results of 230Th/U dating of massive sulfides and metalliferous sediments (288 and 245 analyses, respectively) of hydrothermal sites in the northern equatorial area of the Mid-Atlantic Ridge (MAR) from 12° to 20° N are presented. The maximum and average ages of sulfides are 223 ± 38.2 and 80.5 ka, respectively. The comparison of ages of massive sulfides from various MAR hydrothermal sites showed asynchronous stages of hydrothermal activity along the ridge axis indicating the features of tectonic activity and magmatism, which control the hydrothermal activity within each region. The glaciation periods, which record the activation and low- and high-temperature hydrothermal activity, are an exception. A direct positive correlation between the age of a hydrothermal site and its distance from the axial ridge zone is typical of mafic-related hydrothermal sites in contrast to ultramafic-related hydrothermal sites, which is related to the different scenarios of the formation of these two types of sulfide mineralization within slow-spreading ridges. The ages of sulfides and sediments have been jointly analyzed based on the example of the Pobeda and Semenov hydrothermal sites. The interpretation of data on sediments indicates the continuous character of hydrothermal activity, which is partly supported by the age of sulfides. [ABSTRACT FROM AUTHOR]

This study aimed to investigate the genetic diversity and relationships among Apodemus mystacinus lineages by analyzing mitochondrial Cytochrome b sequences. The study included samples from Iranand south east Turkey (Hakkari and Şırnak), in addition to previously studied populations. The results showed differences in the relationships among lineages and the structure of the phylogenetic tree compared to previous studies. A. m. mystacinus lineage, represented by samples from southwest Anatolia and Crete, was located at the base of the tree. The Iranian specimens were clustered with the southeastern specimens of Turkey in a separate lineage, indicating a possible refugium for A. mystacinus populations during glacial periods. The study also suggested that the expansion of A. mystacinus into Anatolia and neighboring regions during the Pleistocene facilitated its colonization of the Aegean islands. The differentiation between A. m. euxinus lineage and the south east Anatolia-Iran lineage may have resulted from the ancestral population in eastern Turkey diverging into two different lineages with one expanding its range towards the Black Sea and the other migrating towards the Zagros Mountains in Iran. These findings contribute to the understanding of the evolutionary history and phylogeography of A. mystacinus in its main range. [ABSTRACT FROM AUTHOR]

Buried mounds have been identified on seismic reflection profiles in the southern Roosevelt sub-basin of the eastern Ross Sea, Antarctica. Since they have never been sampled, the composition of these mounds can only be inferred from their acoustic character. Previous studies have hypothesised that they are buried glacial moraines deposited by ice grounding near the paleo-continental shelf edge, suggesting the beginning of the growth of the West Antarctic Ice Sheet (WAIS) as early as the late Oligocene. This hypothesis conflicts with earlier evidence of the WAIS advance over the central-eastern Ross Sea. An alternative explanation for the origin of the mounds, as mud volcanoes, is formulated here on the basis of seismic reflection profile reprocessing and comparison with other, better studied, mound provinces in the Ross Sea. Shallow drilling is required to verify, which hypothesis is correct, and this has implications for various WAIS scenarios, ice volumes, and thermal rheological modelling. [ABSTRACT FROM AUTHOR]

The glacial–interglacial cycles of the Quaternary exhibit 41 kyr periodicity before the Mid-Pleistocene Transition (MPT) around 1.2–0.8 Myr ago and ∼ 100 kyr periodicity after that. From the viewpoint of dynamical systems, proposed mechanisms generating these periodicities are broadly divided into two types: (i) nonlinear forced responses of a mono- or multi-stable climate system to the astronomical forcing or (ii) synchronization of internal self-sustained oscillations to the astronomical forcing. In this study, we investigate the dynamics of glacial cycles simulated by the Earth system model of intermediate complexity CLIMBER-2 with a fully interactive carbon cycle, which reproduces the MPT under gradual changes in volcanic-CO 2 degassing and regolith cover. We report that, in this model, the dominant frequency of glacial cycles is set in line with the principle of synchronization. It is found that the model exhibits self-sustained oscillations in the absence of astronomical forcing. Before the MPT, glacial cycles synchronize to the 41 kyr obliquity cycles because the self-sustained oscillations have periodicity relatively close to 41 kyr. After the MPT the timescale of internal oscillations becomes too long to follow every 41 kyr obliquity cycle, and the oscillations synchronize to the 100 kyr eccentricity cycles that modulate the amplitude of climatic precession. The latter synchronization occurs with the help of the 41 kyr obliquity forcing, which enables some terminations and glaciations to occur robustly at their right timing. We term this phenomenon vibration-enhanced synchronization because of its similarity to the noise-enhanced synchronization known in nonlinear science. While we interpret the dominant periodicities of glacial cycles as the result of synchronization of internal self-sustained oscillations to the astronomical forcing, the Quaternary glacial cycles show facets of both synchronization and forced response. [ABSTRACT FROM AUTHOR]

During the Late Pleistocene, the Palaeo-Ems system (PES) was one of the major tributary channels feeding the Elbe Palaeovalley (EPV) and formed an important part of the drainage system of the continental northwestern Europe unglaciated hinterland. In this study, a detailed interpretation of high-resolution 2D sub-bottom profiler and Boomer grids were used to map the overall course of the submerged PES channel, as well as its spatial and stratigraphic relationships with other Quaternary geological units in the German North Sea. Mapping of buried tunnel valleys, a lacustrine-fill unit, straight channel structures was also carried out. The sedimentary record of the PES is represented by a low gradient and meandering channel which branched into two major pathways as it approached the EPV western flank. Its upstream to downstream trends, coupled with seaward decreasing gradient and sinuosity, are similar to those visible in present-day river deltas. Both the PES and EPV subsequently formed a combined depositional system, which was successively drowned due to the fast-rising relative sea level that overwhelmed the adaptation capabilities of the joint drainage system. For the first time, this study sheds light onto the PES/EPV morpho-stratigraphic relationships which played a key role in the coastal landscape architecture of the German North Sea since the Late Pleistocene. [ABSTRACT FROM AUTHOR]

Climatic and environmental conditions play a pivotal role in the evolution of the biosphere, serving as the primary natural factors influencing biological evolution and the development of human civilization. The study of the evolution of Earth's habitability primarily revolves around the reconstruction of climatic and oceanic conditions in geohistorical periods, shedding light on their dynamic changes. This paper collates classic geological indicators and geochemical proxies associated with paleo-climatic and oceanic environmental conditions. The latest "big data" analyses and simulations made possible by the availability of previously unimagined massive datasets reveal several key findings: During the early Paleozoic, atmospheric oxygen levels were low, and widespread oceanic anoxia was prevalent; the Devonian era witnessed a greenhouse climate, followed by the Carboniferous ice age characterized by higher oceanic oxidation levels and alkalinity. The latest Paleozoic deglaciation occurred under high pCO2 conditions, extending into much of the Mesozoic and early Cenozoic, marked by multiple hyperthermal and anoxia expansion events, until the resurgence of global glaciation in the middle-late stages of the Cenozoic, ultimately bringing environmental and climatic conditions closer to modern levels. By correlating the aforementioned long-term trends with major geological events, we can delineate the co-evolution of paleoclimate and oceanic environments in tandem with the development of Tethys tectonics as follows. (1) During the Proto-Tethys stage, global paleo-elevations were relatively low, and atmospheric oxygen levels were also relatively modest. Despite the occurrence of significant tectonic movements that led to noticeable transgressive-regressive cycles, their effects on climate and oceanic environments were somewhat limited due to the relatively weak interactions. (2) The emergence of the Paleo-Tethys was a significant event that coincided with the formation of the supercontinent Pangaea. Intensive orogenic movements during this period increased the global land area and elevation. This, in turn, led to enhanced terrestrial weathering, which elevated sea surface productivity and resulted in massive nutrient input into the oceans. Consequently, this process contributed to the rise of oxygen levels in the atmosphere and a decrease in atmospheric pCO2. These changes are considered potential driving mechanisms for late Paleozoic glaciation and oceanic oxygenation. (3) The transition from the Paleo-Tethys to the Neo-Tethys was closely linked to the breakup of Pangaea. During this period, the terrestrial weathering processes were relatively weak due to decreased continental elevations. This resulted in a long-term greenhouse climate and intermittent global oceanic events, which were responses to the high atmospheric pCO2 levels during the Mesozoic and early Cenozoic eras. (4) The Neo-Tethys stage ended with the dramatic uplift of the Alps-Himalaya Mountain ranges due to the collision of India and Asia. This uplift had a profound global impact, significantly increasing continental elevations. As a result, weathering and carbon burial processes intensified, leading to a reduction in atmospheric pCO2. Concurrently, this uplift played a crucial role in the establishment of the East Asian monsoon and North Atlantic deep-water circulations, both of which played a part in triggering the late Cenozoic ice age. These models suggest that the teleconnections between land and sea (orogeny-terrestrial weathering-marine carbon burial) span over the whole Phanerozoic and might have played a key role in balancing the Earth surface system. Combined, the tectonic, volcanic, paleo-climatic, as well as paleoenvironmental events recorded in the Tethys oceans and adjunct continents represent valuable natural experiments and lessons for understanding the present and the future of Earth's habitability. [ABSTRACT FROM AUTHOR]

Understanding changes in Earth's past can provide valuable insights into prediction of its future. An example is the interactions between the internal and external spheres of Earth. The cyclical northward breakup-drift of Gondwana, driven by the opening and closure of Proto-, Paleo-, and Neo-Tethyan oceans, facilitated the transfer of landmasses from the southern to the northern hemisphere, traversing the tropic region. We have observed a compelling correlation between episodic increases in landmass area within the tropic regions (those lying at less than 20° latitude) and a subsequent temperature decrease during the three major glacial periods in the last 500 million years. This phenomenon can be attributed to low latitude regions receiving more solar energy influx on Earth's surface than high latitude areas. In addition, an increase of landmass in tropic regions (low latitude) attenuates the net energy absorption by the Earth's surface, consequently impeding the conduction and convection of absorbed energy toward the poles. The result is a decrease in global surface temperature. The tropic regions, benefiting from abundant sunlight, create an ideal environment for the proliferation of marine plankton species. These species are important in the generation of organic-rich sediment. Massive biological debris is therefore deposited on continental margins when a continent drifts across the tropic region. This creates favorable conditions for future hydrocarbon and reservoir formation. Northward subduction of organic-rich sediments during the closure of the Tethyan oceans results in the generation of mafic arc magmas with low oxygen fugacity. This chemical environment helps the mineralization of reduced-type ore deposits such as tungsten, tin, and lithium. Subducted-driven plate tectonics in the Tethys realm changes the distribution of oceans and landmass, subsequently affecting the balance and distribution of solar energy across Earth's surface. These changes trigger consequential environmental shifts which in turn, impact the composition of rock and mineral along the Eurasian margin due to subduction. Consequently, the Tethyan realm and its history is an ideal natural laboratory for comprehending the processes and changes of the entire Earth's system. [ABSTRACT FROM AUTHOR]

Models (paradigms) and former interpretations have often been presupposed when conducting field research. In the 19th century diamictites were for the first time interpreted to have originated from ancient glaciations. These interpretations have to a large part prevailed in the geological community, although there has been much progress in the areas of sedimentology, glaciology and physical geography. The present work is an effort to find criteria which most clearly discriminate between geological features produced by different processes, mainly glaciation and mass flow, the latter predominantly sediment gravity flows. Geological features which have been interpreted to have formed by glaciation throughout pre-Pleistocene Earth history are compared to similar-appearing geological features formed by mass flow and tectonics, so as to uncover variations in the appearance between features resulting from these different processes. The starting point for this comparison is documentation of the appearance of Quaternary products of erosion and deposition, in order to discern the origin of older formations. It is shown that the appearance and origin of pavements, dropstones, valleys, small-scale landforms, surface microtextures and most other geological features may in some cases be equivocal, but in others the details are indicative of the process which generated the feature. Detailed geological field data which have been compiled by geologists from outcrops of pre-Pleistocene strata, more often than is considered in most papers, commonly point to a mass flow origin, mainly a sediment gravity flow origin, rather than a glaciogenic origin. A process of multiple working hypotheses or interpretations is therefore advocated, based mainly on a comparison of the appearance of features formed by different geological processes documented from different research disciplines. Instead of starting with current interpretations or models, this multiple working hypothesis or methodology helps to avoid confirmation bias and jumping to conclusions. [ABSTRACT FROM AUTHOR]

The prevailing paradigm about the Quaternary ecological and evolutionary history of Central European ecosystems is that they were repeatedly impoverished by regional extinctions of most species during the glacial periods, followed by massive recolonizations from southern and eastern refugia during interglacial periods. Recent literature partially contradicts this view and provides evidence to re‐evaluate this Postglacial Recolonization Hypothesis and develop an alternative one. We examined the long‐term history of the flora of the Carpathian (Pannonian) Basin by synthesising recent advances in ecological, phylogeographical, palaeoecological and palaeoclimatological research, and analysing the cold tolerance of the native flora of a test area (Hungary, the central part of the Carpathian Basin). We found that (1) many species have likely occurred there continuously since before the Last Glacial Maximum (LGM); (2) most of the present‐day native flora (1404 species, about 80%) can occur in climates as cold as or colder than the LGM (mean annual temperature ≤+3.5°C); and (3) grasslands and forests can be species‐rich under an LGM‐like cold climate. These arguments support an alternative hypothesis, which we call the Flora Continuity Hypothesis. It states that long‐term continuity of much of the flora in the Carpathian Basin is more plausible than regional extinctions during the LGM followed by massive postglacial recolonizations. The long‐term continuity of the region's flora may have fundamental implications not only for understanding local biogeography and ecology (e.g. the temporal scale of processes), but also for conservation strategies focusing on protecting ancient species‐rich ecosystems and local gene pools. [ABSTRACT FROM AUTHOR]

We present new 14C results measured on subfossil Scots Pines recovered in the eroded banks of the Drouzet watercourse in the Southern French Alps. About 400 new 14C ages have been analysed on 15 trees sampled at annual resolution. The resulting Δ14C record exhibits an abrupt spike occurring in a single year at 14 300–14 299 cal yr BP and a century-long event between 14 and 13.9 cal kyr BP. In order to identify the causes of these events, we compare the Drouzet Δ14C record with simulations of Δ14C based on the 10Be record in Greenland ice used as an input of a carbon cycle model. The correspondence with 10Be anomalies allows us to propose the 14.3 cal kyr BP event as a solar energetic particle event. By contrast, the 14 cal kyr BP event lasted about a century and is most probably a common Maunder-type solar minimum linked to the modulation of galactic cosmic particles by the heliomagnetic field. We also discuss and speculate about the synchroneity and the possible causes of the 14 cal kyr BP event with the brief cold phase called Older Dryas, which separates the Bølling and Allerød millennium-long warm phases of the Late Glacial period. This article is part of the Theo Murphy meeting issue 'Radiocarbon in the Anthropocene'. [ABSTRACT FROM AUTHOR]

Vicia sepium (bush vetch) is a perennial legume widely distributed throughout the Eurasian continent. However, its distribution in Japan is limited to Mt. Ibuki and small parts of central and southern Hokkaido. Therefore, each Japanese V. sepium lineage has been considered to have been introduced separately from Europe. Here, we examined whether the species was introduced or not on the basis of cpDNA sequences and genome-wide SNPs from Japanese and overseas samples. Both the cpDNA haplotype network and the nuclear DNA phylogenetic tree showed that Japanese V. sepium is monophyletic. Furthermore, although the nuclear DNA phylogenetic tree also showed that each lineage is clearly monophyletic, genetic admixture of the genetic cluster dominated in the Hokkaido lineage was also detected in the Mt. Ibuki lineage. Population divergence analysis showed that the two lineages diverged during the last glacial period. The Mt. Ibuki lineage showed a sudden population decline 300–400 years ago, indicating that some anthropogenic activity might be involved, while the Hokkaido lineage showed a gradual population decline from 5000 years ago. Consequently, these two lineages show low current genetic diversity compared with overseas lineages. These results show that the Japanese V. sepium is not introduced but is native. [ABSTRACT FROM AUTHOR]

The intertropical convergence zone (ITCZ) plays a key role in regulating tropical hydroclimate and global water cycle through changes in its convection strength, latitudinal position, and width. The long-term variability of the ITCZ, along with the corresponding driving mechanisms, however, remains obscure, mainly because it is difficult to separate different ITCZ variables in paleoclimate proxy records. Here, we report a speleothem oxygen isotope (d18O) record from southwestern Sulawesi, Indonesia, and compile it with other speleothem records from the Maritime Continent. Using the spatial gradient of speleothem d18O along a transect across the ITCZ, we constrain ITCZ variabilities over the Maritime Continent during the past 30,000 y. We find that ITCZ convection strength overall intensified from the last glacial period to the Holocene, following changes in climate boundary conditions. The mean position of the regional ITCZ has moved latitudinally no more than 3° in the past 30,000 y, consistent with the deduction from the atmospheric energy framework. However, different from modern observations and model simulations for future warming, the ITCZ appeared narrower during both the late Holocene and most part of the last glacial period, and its expansion occurred during Heinrich stadials and the early-to-mid Holocene. We also find that during the last glacial and deglacial period, prominent millennial-scale ITCZ changes were closely tied to the variability of the Atlantic meridional overturning circulation (AMOC), whereas during the Holocene, they were predominantly modulated by the long-term variability of the Walker circulation. [ABSTRACT FROM AUTHOR]

Composition of stable carbon (δ13C) and nitrogen (δ15N) isotopes of bone collagen of large mammals who inhabited Southern Siberia during MIS2 have been analysed. The results suggest significant isotopic differences of those animals from the fauna of other regions. Notably, the differences between animals from neighbouring regions may be more significant than between those from more distant areas. A summary description of the isotopic signatures of the LGP mammoth fauna from the Minusinsk depression has been presented, showing a general pattern of lower δ15N and higher δ13C values as compared to species from other regions. Variations in δ15N values may be explained by strong influence of landscape and climatic factors, in particular, the highly mosaic nature of local landscapes due to its ruggedness and altitudinal zonation. One of the possible mechanisms that could explain the observed δ13C signatures in bone collagen of the mammals is regional geochemistry, namely, the presence of developed system of mineral lakes and saline soils in the area. On saline soils, halophytic plants using the C 4 type of photosynthesis and characterized by higher δ13C values, are more common. Furthermore, some halophytes, being C 3 plants, are able to adapt to salinity stress and fix carbon in a way similar to C 4 plants. [ABSTRACT FROM AUTHOR]

Orbital precession has been linked to glacial cycles and the atmospheric carbon dioxide (CO2) concentration, yet the direct impact of precession on the carbon cycle is not well understood. We analyze output from an Earth system model configured under different orbital parameters to isolate the impact of precession on air‐sea CO2 flux in the Southern Ocean—a component of the global carbon cycle that is thought to play a key role on past atmospheric CO2 variations. Here, we demonstrate that periods of high precession are coincident with anomalous CO2 outgassing from the Southern Ocean. Under high precession, we find a poleward shift in the southern westerly winds, enhanced Southern Ocean meridional overturning, and an increase in the surface ocean partial pressure of CO2 along the core of the Antarctic Circumpolar Current. These results suggest that orbital precession may have played an important role in driving changes in atmospheric CO2. Plain Language Summary: Over the past one million years, Earth has experienced several glacial and interglacial periods. As a glacial period is ending, carbon in the atmosphere can rise by up to 50%. The cause for this change is currently unknown, but most theories suggest that this carbon is released from the deep ocean into the atmosphere. The Southern Ocean surrounding Antarctica is the location of a lot of carbon outgassing from the deep ocean into the atmosphere, so it could be responsible for some of this change in atmospheric carbon. One of Earth's orbital cycles, precession, has been shown to change circulation in the Southern Ocean, that can affect how much carbon is carried from the deep ocean to the surface and released into the atmosphere. This paper uses simulations of a climate model to show that high precession corresponds to a 20% increase in the release of carbon from the Southern Ocean into the atmosphere. These findings suggest that precession could have affected changes in past atmospheric carbon concentrations. Key Points: Increased insolation during austral summer due to orbital precession shifts the southern westerlies polewardPoleward shifted westerlies enhance CO2 outgassing due to increased turbulent exchange and vertical transport of carbon‐rich watersEnhanced transport of carbon‐rich waters is driven by a deepening of the overturning circulation in response to poleward shifted winds [ABSTRACT FROM AUTHOR]

Germline mutations are the ultimate source of genetic variation and the raw material for organismal evolution. Despite their significance, the frequency and genomic locations of mutations, as well as potential sex bias, are yet to be widely investigated in most species. To address these gaps, we conducted whole-genome sequencing of 12 great reed warblers (Acrocephalus arundinaceus) in a pedigree spanning 3 generations to identify single-nucleotide de novo mutations (DNMs) and estimate the germline mutation rate. We detected 82 DNMs within the pedigree, primarily enriched at CpG sites but otherwise randomly located along the chromosomes. Furthermore, we observed a pronounced sex bias in DNM occurrence, with male warblers exhibiting three times more mutations than females. After correction for false negatives and adjusting for callable sites, we obtained a mutation rate of 7.16 × 10−9 mutations per site per generation (m/s/g) for the autosomes and 5.10 × 10−9 m/s/g for the Z chromosome. To demonstrate the utility of species-specific mutation rates, we applied our autosomal mutation rate in models reconstructing the demographic history of the great reed warbler. We uncovered signs of drastic population size reductions predating the last glacial period (LGP) and reduced gene flow between western and eastern populations during the LGP. In conclusion, our results provide one of the few direct estimates of the mutation rate in wild songbirds and evidence for male-driven mutations in accordance with theoretical expectations. [ABSTRACT FROM AUTHOR]

Premise: Glacial/interglacial cycles and topographic complexity are both considered to have shaped today's diverse phylogeographic patterns of taxa from unglaciated eastern North America (ENA). However, few studies have focused on the phylogeography and population dynamics of wide‐ranging ENA herbaceous species occurring in forest understory habitat. We examined the phylogeographic pattern and evolutionary history of Podophyllum peltatum L., a widely distributed herb inhabiting deciduous forests of ENA. Methods: Using chloroplast DNA (cpDNA) sequences and nuclear microsatellite loci, we investigated the population structure and genetic diversity of the species. Molecular dating, demographic history analyses, and ecological niche modeling were also performed to illustrate the phylogeographic patterns. Results: Our cpDNA results identified three main groups that are largely congruent with boundaries along the Appalachian Mountains and the Mississippi River, two major geographic barriers in ENA. Populations located to the east of the Appalachians and along the central Appalachians exhibited relatively higher levels of genetic diversity. Extant lineages may have diverged during the late Miocene, and range expansions of different groups may have happened during the Pleistocene glacial/interglacial cycles. Conclusions: Our findings indicate that geographic barriers may have started to facilitate the population divergence in P. peltatum before the Pleistocene. Persistence in multiple refugia, including areas around the central Appalachians during the Quaternary glacial period, and subsequent expansions under hospitable climatic condition, especially westward expansion, are likely responsible for the species' contemporary genetic structure and phylogeographic pattern. [ABSTRACT FROM AUTHOR]

Located at the modern junction of the Asian Summer Monsoon and the Westerlies, the northeastern Tibetan Plateau and western Chinese Loess Plateau are in distinct climatic setting from the middle and eastern Chinese Loess Plateau. Besides, Holocene climate variations near the Asian Summer Monsoon margin are highly debated with different models proposed. We carried out environmental magnetic analyses on the Minle loess section, with continuous deposition between 13.3–0.5 ka, located near this margin. Results show that the magnetic susceptibilities of palaeosols are dominantly contributed by superparamagnetic (SP) and single-domain (SD) maghemite and/or magnetite produced by pedogenesis. Limited changes in the content of haematite indicate that dust origin hardly influenced the magnetic mineral variations. The section is divided into four substages according to the changes in magnetic indices and provides a full scene of Holocene climatic evolutions. During the coldest and driest Late Glacial (13.3–11.7 ka), it displays the weakest pedogenesis, as suggested by the lowest SP and SD concentration. The strongest pedogenesis in the Minle section produced higher magnetic susceptibility than the loess records in the Chinese Loess Plateau during the early Holocene Optimum (11.7–8.1 ka). The subsequently declined summer insolation, equatorward migrated Westerlies and the weakened Asian Summer Monsoon led to weak pedogenesis during the middle Holocene (8.1–5.3 ka). Stronger pedogenesis during the late Holocene (5.3–0.5 ka) than the middle Holocene might be due to lower evapotranspiration from weaker insolation and/or to the enhanced winter Westerlies. We attribute the spatiotemporal differences in climatic records of the Chinese loess to precipitation, effective humidity and aeolian geomorphological processes. [ABSTRACT FROM AUTHOR]

During the last glacial period, rapidly changing environments posed substantial challenges to Neanderthal populations in Europe. Southern continental regions, such as Iberia, have been proposed as important climatic "buffer" zones during glacial phases. Contextualising the climatic and ecological conditions Neanderthals faced is relevant to interpreting their resilience. However, records of the environments and ecosystems they exploited across Iberia exhibit temporal and spatial gaps in coverage. Here we provide new evidence for palaeotemperatures, vegetation structure, and prey herbivore ecology during the late Pleistocene (MIS 5-3) in northern Spain, by applying multiple stable isotope tracers (δ18O, δ13C, δ15N, δ34S) to herbivore skeletal remains associated with Neanderthal occupations at Axlor Cave, Bizkaia. The results show little change over time and indicate stable climatic conditions and ecosystems across different occupations. Large within-layer isotopic variability in nitrogen and sulphur suggests the presence of a mosaic environment and a variety of isotopic ecotones that were exploited by Neanderthals and their prey. We implement a combination of carbonate and phosphate δ18O measurements to estimate palaeotemperatures using a cost-effective workflow. We show that the targeted use of phosphate δ18O measurements to anchor summer peak and winter trough areas enables high-precision seasonal palaeoclimatic reconstructions. [ABSTRACT FROM AUTHOR]

The Southern Ocean (SO) plays a fundamental role in global climate due to the presence of the intense eastward‐flowing Antarctic Circumpolar Current (ACC), one of the most important ocean current systems. The configuration of the frontal systems of the ACC is controlled by the orbital‐ and millennial‐scale variations of the Southern Hemisphere westerly winds (SHWW) and the SO upwelling. However, the reconstruction of paleoclimate and paleocurrent in the SO remains controversial possibly because of the complex interpretation of paleo‐proxies and the regional variations. Here, we present results from rock magnetic measurements and electron microscopic analyses on marine core MD11‐3353 over the past 150 Kyr, which is located in the Polar Front Zone, west of the Kerguelen Plateau. Our data sets indicate that magnetic mineral assemblages in the core are dominated by detrital magnetic minerals mixed with biogenic magnetic minerals (i.e., magnetofossils formed by magnetotactic bacteria) during the interglacial periods. Changes in the detrital magnetic mineral content indicate a strong modulation of the ACC intensity and the SHWW stress at the orbital scale over the last climatic cycle with an enhanced activity during the glacial periods. The increase in magnetofossils content during the interglacial periods indicates an enhanced nutrient supply from the SO upwelling resulting from the southward migration of the Antarctic Polar Front. Our results suggest that the variations of concentration and assemblage of magnetic minerals can be used as faithful proxies for reconstructing ocean circulation and upwelling changes in the South Indian Ocean over the past 150 Kyr. Plain Language Summary: The Southern Ocean plays a critical role in climate, ocean circulation, oceanic carbon sequestration, and nutrient distribution, in particular via the Antarctic Circumpolar Current (ACC), the largest wind‐driven current on Earth. Reconstructing the past variability of the intensity and position of the ACC is challenging. Indeed, rather different results were obtained from different areas suggesting a strong regional dependence. In order to better decipher the mechanisms involved in the southern Indian sector, we performed detailed environmental magnetic analyses on a marine core collected west of the Kerguelen Plateau, presently under the influence of the ACC. Both detrital and biogenic magnetic minerals were identified over the past 150 Kyr, corresponding to the last climatic cycle. The temporal variations of detrital magnetic minerals suggest an enhanced intensity of the ACC during the glacial periods. In contrast, increased abundance of biogenic magnetic minerals during the interglacial periods indicates an increased nutrient supply associated with an enhanced Southern Ocean upwelling. Key Points: Magnetic minerals in core MD11‐3353 record paleoenvironmental changes in the South Indian Ocean over the past 150 KyrAbundant detrital magnetic minerals illustrate an enhanced intensity of the Antarctic Circumpolar Current during the glacial periodsIncreased magnetofossils indicate an increased nutrient supply associated with the Southern Ocean upwelling during the interglacial periods [ABSTRACT FROM AUTHOR]

The total air content (TAC) of polar ice cores has long been considered a potential proxy for past ice sheet elevation. Recent work, however, has shown that a variety of other factors also influence this parameter. In this paper we present a high-resolution TAC record from the South Pole ice core (SPC14) covering the last 54 000 years and discuss the implications of the data for interpreting TAC from ice cores. The SPC14 TAC record shows multiple features of interest, including (1) long-term orbital-scale variability, (2) millennial-scale variability in the Holocene and last glacial period, and (3) a period of stability from 35 to 25 ka. The longer, orbital-scale variations in TAC are highly correlated with integrated summer insolation (ISI), corroborating the potential of TAC to provide an independent dating tool via orbital tuning. Large millennial-scale variability in TAC during the last glacial period is positively correlated with past accumulation rate reconstructions as well as δ15 N-N 2 , a firn thickness proxy. These TAC variations are too large to be controlled by direct effects of temperature and too rapid to be tied to elevation changes. We propose that grain size metamorphism near the firn surface explains these changes. We note, however, that at sites with different climate histories than the South Pole, TAC variations may be dominated by other processes. Our observations of millennial-scale variations in TAC show a different relationship with accumulation rate than observed at sites in Greenland. [ABSTRACT FROM AUTHOR]

The North Sea Last Interglacial sea level is sensitive to the fingerprint of mass loss from polar ice sheets. However, the signal is complicated by the influence of glacial isostatic adjustment driven by Penultimate Glacial Period ice-sheet changes, and yet these ice-sheet geometries remain significantly uncertain. Here, we produce new reconstructions of the Eurasian ice sheet during the Penultimate Glacial Maximum (PGM) by employing large ensemble experiments from a simple ice-sheet model that depends solely on basal shear stress, ice extent, and topography. To explore the range of uncertainty in possible ice geometries, we use a parameterised shear-stress map as input that has been developed to incorporate bedrock characteristics and the influence of ice-sheet basal processes. We perform Bayesian uncertainty quantification, utilising Gaussian process emulation, to calibrate against global ice-sheet reconstructions of the Last Deglaciation and rule out combinations of input parameters that produce unrealistic ice sheets. The refined parameter space is then applied to the PGM to create an ensemble of constrained 3D Eurasian ice-sheet geometries. Our reconstructed PGM Eurasian ice-sheet volume is 48±8 m sea-level equivalent (SLE). We find that the Barents–Kara Sea region displays both the largest mean volume and volume uncertainty of 24±8 m SLE while the British–Irish sector volume of 1.7±0.2 m SLE is the smallest. Our new workflow may be applied to other locations and periods where ice-sheet histories have limited empirical data. [ABSTRACT FROM AUTHOR]

The expansion of oxygen deficient zones (ODZs) within the ocean's interior is anticipated to be a major consequence of anthropogenic climate change, but past changes in ODZs are poorly defined. Recent mapping efforts have revealed plumes of the redox‐active metal cobalt within ODZs, driving a basin‐scale correlation between high cobalt and low O2. Here, we investigate the cobalt flux to Equatorial Pacific sediments along the Line Islands Ridge as a novel record of basin‐scale fluctuations in ODZ extent. After accounting for remobilization by diagenesis, we document a ∼40% increase in cobalt accumulation over the last glacial period, with a more pronounced peak during the Last Glacial Maximum, indicative of larger ODZs compared to the Holocene. Our results link ODZ expansion with colder climates and lend support to model‐based assertions that ongoing deoxygenation may reflect a transient response to warming. Plain Language Summary: Climate change is linked to a decline in ocean oxygen levels, impacting fish and other organisms that need oxygen to breathe. Knowledge of past changes in ocean oxygen would help put ongoing deoxygenation trends into context. In this study, we investigated changes in oxygen in the Pacific Ocean over the past 145,000 years. Because low‐oxygen waters are enriched in the metal cobalt, we reconstructed the cobalt abundance of the past oceans as a proxy for oxygen. During the past two Ice Ages, when Earth was colder than today, we find evidence for higher cobalt, and therefore an expansion of oxygen‐poor waters. Key Points: The cobalt flux to pelagic sediments reflects heightened sources associated with Oxygen Deficient ZonesIn Equatorial Pacific sediments, cobalt flux increased by ∼40% during the Last Glacial Period, compared to the HoloceneOxygen Deficient Zones likely expanded during the previous two glacial periods [ABSTRACT FROM AUTHOR]

Although most ancient DNA studies have focused on the last 50,000 years, paleogenomic approaches can now reach into the early Pleistocene, an epoch of repeated environmental changes that shaped present-day biodiversity. Emerging deep-time genomic transects, including from DNA preserved in sediments, will enable inference of adaptive evolution, discovery of unrecognized species, and exploration of how glaciations, volcanism, and paleomagnetic reversals shaped demography and community composition. In this Review, we explore the state-of-the-art in paleogenomics and discuss key challenges, including technical limitations, evolutionary divergence and associated biases, and the need for more precise dating of remains and sediments. We conclude that with improvements in laboratory and computational methods, the emerging field of deep-time paleogenomics will expand the range of questions addressable using ancient DNA. [ABSTRACT FROM AUTHOR]

Intraspecific genetic diversity is a key aspect of biodiversity. Quaternary climatic change and glaciation influenced intraspecific genetic diversity by promoting range shifts and population size change. However, the extent to which glaciation affected genetic diversity on a global scale is not well established. Here we quantify nucleotide diversity, a common metric of intraspecific genetic diversity, in more than 38,000 plant and animal species using georeferenced DNA sequences from millions of samples. Results demonstrate that tropical species contain significantly more intraspecific genetic diversity than nontropical species. To explore potential evolutionary processes that may have contributed to this pattern, we calculated summary statistics that measure population demographic change and detected significant correlations between these statistics and latitude. We find that nontropical species are more likely to deviate from neutral expectations, indicating that they have historically experienced dramatic fluctuations in population size likely associated with Pleistocene glacial cycles. By analyzing the most comprehensive data set to date, our results imply that Quaternary climate perturbations may be more important as a process driving the latitudinal gradient in species richness than previously appreciated. [ABSTRACT FROM AUTHOR]

During the Last Glacial Period, the climate shift to cold conditions associated with changes in atmospheric circulation and vegetation cover resulted in the development of large aeolian systems in Europe. On a regional scale, many factors may have influenced dust dynamics, such as the latitudinal difference between the various aeolian systems and the variability of the sources of wind-transported particles. Therefore, the assumption that the timing of aeolian deposition is strictly synchronous in Europe does not seem to be the most plausible hypothesis and needs to be evaluated. To test this assumption, the chronology of loess deposition in different European regions was investigated by studying 93 luminescence-dated loess–palaeosol sequences with their data recalculated and compiled in a single comma separated values (*.csv) file: the ChronoLoess database. Our study shows that the two major aeolian systems, the Northern European Loess Belt (NELB) on the one hand and the systems associated with the rivers draining the Alpine Ice Sheet on the other hand, developed asynchronously. The significant deposition started at about 32 kyr b2k for the NELB vs. 42 kyr b2k for the perialpine loess and peaked about 2 millennia later for the former (21.8 vs. 23.9 kyr b2k, respectively). This shift resulted mainly from the time lag between the maxima of the Alpine and Fennoscandian ice sheets, which acted as the primary sources of fine-grained particles through glacial abrasion. The major geomorphic changes that resulted from the development and decay of the Fennoscandian and British–Irish ice sheets also played an important role. Particularly, ice sheet coalescence during the Last Glacial Maximum (LGM) diverted meltwater fluxes through the Channel River and provided vast amounts of glacial particles available for deflation in the western NELB. The period during which the maximum mass accumulation rate was reached for each loess–palaeosol sequence is relatively homogeneous in the NELB and ranges from 30 to 19 kyr b2k, whereas it is more scattered in the perialpine systems (>60 to 14 kyr b2k). This probably resulted from a combination of factors, including the asynchrony of maximum valley glacier advances and local geomorphic factors. The ChronoLoess database is available at 10.5281/zenodo.7728616 (Bosq et al., 2023). [ABSTRACT FROM AUTHOR]

A striated surface is present at an erosional unconformity between foliated Paleoproterozoic Michigamme Formation and fluvial conglomerate and sandstone of the Neoproterozoic Jacobsville Formation exposed at L’Anse Bay (Michigan, USA). These striations have been interpreted to be the result of ice flow in either the Proterozoic, the Pleistocene, or the modern. Recently, the glacial origin interpretation for this striated surface has been used to argue that it may be related to ca. 717–635 Ma Cryogenian snowball Earth glaciation. This interpretation would make the surface a rare example of a Neoproterozoic glacial pavement, with major chronostratigraphic implications that in turn impose constraints on the timing of intracratonic erosion related to the formation of the Great Unconformity. In this contribution, we present new observations showing that the surface is a tectonic slickenside caused by largely unconformity-parallel slip along the erosional unconformity. We document structural repetition of the Michigamme-Jacobsville contact with associated small-scale folding. The unconformity-parallel slip transitions into thrust faults that ramp up into the overlying Jacobsville Formation. We interpret that the surface records contractional deformation rather than ancient glaciation, recent ice movement, or recent mass wasting. The faulting likely occurred during the Rigolet phase of the Grenvillian orogeny, which also folded the Jacobsville Formation in the footwall of the Keweenaw fault. [ABSTRACT FROM AUTHOR]

Proxy reconstructions and model simulations of precipitation during Earth's glacial periods suggest that the locations and mechanisms of atmospheric moisture transport have changed considerably during Earth's past. We investigate the hydroclimate of the Last Glacial Maximum (LGM) using simulations with the Community Earth System Model, with a focus on the extratropics and the influence of atmospheric rivers (ARs), a key driver of modern‐day moisture transport globally. Mean and extreme precipitation increase significantly over southwestern Patagonia, Iberia, and southwestern North America—mid‐latitude regions affected by ARs in the modern climate—despite overall decreases elsewhere. In each, the associated moisture transport changes are different, with increased transport and AR activity mainly occurring in the North Atlantic. The overall LGM response is dominated by the response to ice sheets, with other forcings causing additional cooling and drying over the extratropics and a strong decrease of moisture transport over the subpolar North Atlantic. Plain Language Summary: During the last ice age, when glaciers reached their maximum extent, atmospheric CO2 was lower and Earth's orbit was different. All of these influences caused dramatic changes in precipitation patterns around the planet. Using climate model simulations, we find that the majority of the changes to atmospheric moisture transport and precipitation patterns result from the presence of the ice sheets alone, with lower CO2 and insolation differences enhancing the ice sheet‐induced patterns. These changes mainly comprise decreases in moisture transport and lower precipitation, with three notable exceptions in Patagonia, Iberia, and southwestern North America. Of these, precipitation increases over Iberia result from increased transport by plumes of moisture, known as atmospheric rivers , across the North Atlantic. Elsewhere in the world, AR activity decreases. Key Points: Average and extreme precipitation declined globally during the Last Glacial Maximum with three notable mid‐latitude exceptions over landMoisture transport changes mainly caused by ice sheets, with lower CO2 and altered insolation causing enhanced drying regionallyAtmospheric river activity decreased globally except over the North Atlantic, where it enhanced precipitation over Iberia [ABSTRACT FROM AUTHOR]

How the climate responded to orbital forcing during the Neoproterozoic snowball Earth events, the most extreme glaciations on Earth, is still unclear. Here, we investigate this problem using a climate model. To simplify the analysis, continents are removed. The results show that even in this simplified situation, the snowball Earth climate is sensitive to orbital configurations. The globally averaged annual surface temperature can differ by 2.4°C, and the maximum monthly mean temperature can differ by 3.7°C under different orbital configurations. Therefore, a snowball Earth could be deglaciated more easily in some orbital configurations than in others. The climatic effect of a particular orbital parameter is highly dependent on the values of other parameters. For example, the effect of obliquity on tropical surface temperature is generally small (<1°C), but it can become large (3.8°C) when eccentricity is large and the northern autumn occurs at perihelion (precession = 180°). Surprisingly, the global temperature is generally lower at high eccentricity than at near-zero eccentricity, even though the total insolation received by Earth is higher in the former than in the latter. Moreover, we find that the Milankovitch hypothesis is valid not only in the extratropical region, but also in the tropics; the snow thickness in the tropical region is inversely proportional to the maximum monthly insolation received in this region. [ABSTRACT FROM AUTHOR]

Evidence of glaciation is recognized in Earth's history from 2.9 Ga to the present, providing important information regarding the climatic, sedimentary, and tectonic evolution of our planet. Glaciers are highly effective agents of erosion that generate and transport large amounts of sediments for 100ʹs of kilometres. Therefore, detrital zircon geochronology of glaciogenic sedimentary rocks can elucidate the provenance and evolution of the sedimentary record through time. In this study, we investigate the Paleoproterozoic Glaciation Event which is hypothesized to be the oldest global glaciation in Earth's history (2.4 to 2.2 Ga). We identify distinct sedimentary provenance patterns between the Archaean supercratons Sclavia and Superia, which, comprised most of the extant Archean crust. The detrital zircon of Sclavia exhibit increasing dissimilarity through time whereas the detrital zircon ages of Superia show consistent age peaks through time. Coupled with the absence of glacial deposits and predominance of marine sedimentary successions within Sclavia, the detrital zircon provenance likely indicates limited subaerial exposure of continental crust in Sclavia with glaciers narrow mountain belts producing no diamictites. This model resolves previous issues related to hypotheses proposing high-obliquity low latitude glaciation of Superia as the only explanation available. [ABSTRACT FROM AUTHOR]

Amphioctopus aegina is an economically important species that has been intensively exploited in the marine areas along the Chinese coast. However, the genetic variation and population genetic structure, which would provide valuable information for their fisheries management, have rarely been investigated. In this study, the genetic variation within and among four A. aegina populations throughout its full distribution range were estimated based on mitochondrial cytochrome b DNA sequences. Our results indicated low (Qinzhou) to high (Dongshan) genetic diversities among the four populations. Analysis of molecular variance (AMOVA), FST statistics, phylogenetic tree and haplotype networks revealed two significant (p < 0.01) divergent lineages with a FST value of 0.7116 between them, one from a population in Qinzhou and the other from the remaining three populations of Dongshan, Huizhou and Zhanjiang. However, the low genetic distance (0.0032) and only two fixed substitutions between them suggest their recent divergence is possibly due to the last glacial period barriers to gene flow produced by the Leizhou Peninsula. The observed lineage divergence suggests that populations of A. aegina in China are genetically subdivided and may represent evolutionary lineages that should be managed individually. [ABSTRACT FROM AUTHOR]

Ice coverage not only affects the climate and landscape of geographical regions but has impacted species composition, the fragmentation and isolation of populations, and the colonisation routes of species post-glaciation. Major advancements in generating genetic data and applying sophisticated analyses to accurately model the demographic and colonisation history of animal and plant species has allowed evolutionary biologists novel insights. Meanwhile, physical geographers have made major advancements in reconstructing glacial history. However, the information flow between the geographic and evolutionary fields on this topic remains limited; consequently, evolutionary studies on contemporary biodiversity and species colonisation tend to be vague about the role of glacial history, while evolutionary and biodiversity information is rarely leveraged when discussing historical glaciation. In this review, we bring together current knowledge on the changing patterns of ice coverage in the British Isles from the maximum extent of the British-Irish ice sheet (BIIS) ca. 27 ka through to the end of large-scale ice coverage at the start of the Holocene period ca. 11.5 ka. We do so to then highlight how glaciation affected species composition during this time period and the subsequent colonisation of temperate flora and fauna and the patterns of genetic variation seen in them. [ABSTRACT FROM AUTHOR]

The results of U–Pb (ID-TIMS) and U–Th–Pb (LA-ICP-MS) geochronological studies of baddeleyite from dolerite dikes of the Sulumat Complex and detrital zircon from red arkose sandstones of the Kebekta Group of the Ugui graben, Aldan Shield, are presented. It has been established that the Kebekta Group has an age of 2.01–1.87 Ga. The provenance areas of the Kebekta Group deposits were the Archean (2.92–2.52 Ga) igneous and metamorphic complexes of the Chara–Olekma Geoblock and the zone of its junction with the Western Aldan Megablock of the Aldan Shield, as well as the Paleoproterozoic (approximately 2.01 Ga) complexes unidentified on the present erosion level. The obtained geochronological data do not contradict the correlation of terrigenous rocks of the Kebekta Group of the Ugui graben and the Kemen Group of the Kodar–Udokan trough. The deposition of arkose sandstones of the Kebekta Group correlates in age with the glaciations in Australia and Sweden (approximately 1.9–1.8 Ga) associated with the formation of the Columbia/Nuna supercontinent. It cannot be excluded either that the deposition of the rocks in the Ugui graben was related to the inflow of glacial material into the intracontinental extensional basin from the southern and/or western (in modern coordinates) framing of the Chara–Olekma Geoblock at the stage of collapse of the Paleoproterozoic orogen. [ABSTRACT FROM AUTHOR]

Abstract Natural analogues are systems that have evolved over geological timescales with features similar to one or several components of a deep geological repository (DGR). Natural analogues complement short-duration laboratory studies since they are existing reflections of many long-term processes that might affect the performance of a repository. Mathematical models are often used for the post-closure safety assessment of a DGR. Confidence in the models’ predictions is enhanced when the models successfully simulate the past evolution of a natural analogue. This paper summarizes the Canadian Nuclear Safety Commission’s (CNSC’s) recent research on natural analogues to inform on (1) glacial erosion, (2) engineered barrier system, and (3) uranium reactive transport in the context of DGRs for radioactive wastes. Glaciation and its erosion are prominent factors impacting the performance of future DGRs at high latitudes in the northern hemisphere. The authors have reviewed the field data from the Greenland Analogue Project, developed a conceptual and mathematical model for the simulation of the thermal conditions within the Greenland ice sheet, as well as the thermal-hydraulic conditions at its base and the ice sheet velocity, and eventually estimated the erosion rate at the site.The Cigar Lake Analogue demonstrates the long-term radionuclide containment capability of the illite clay zone enveloping the ore body, serving as an analogy to the engineered clay barriers. The CNSC and University of Ottawa analyzed 129I in the Cigar Lake core samples, and modeled and correlated the diffusion-dominated transport of radionuclides over the geological evolution of the Cigar Lake deposit. The results provide information on the mobility of fission products and significant radionuclides in conditions analogous to the source, engineered barriers, and near-field host rock of a DGR.The reactive transport and geochemistry of the Kiggavik-Andrew Lake uranium deposit mineralization and remobilization was another natural uranium deposit analogue studied by the CNSC. A reactive transport model was established according to the conceptualized geochemical processes and run under specified boundary and initial conditions to validate the geochemical processes. The geometry, timing, geochemistry, and fluid composition were used as model constraints. [ABSTRACT FROM AUTHOR]

The Pliocene Epoch (∼5.3–2.6 million years ago, Ma) was characterized by a warmer than present climate with smaller Northern Hemisphere ice sheets, and offers an example of a climate system in long‐term equilibrium with current or predicted near‐future atmospheric CO2 concentrations (pCO2). A long‐term trend of ice‐sheet expansion led to more pronounced glacial (cold) stages by the end of the Pliocene (∼2.6 Ma), known as the "intensification of Northern Hemisphere Glaciation" (iNHG). We assessed the spatial and temporal variability of ocean temperatures and ice‐volume indicators through the late Pliocene and early Pleistocene (from 3.3 to 2.4 Ma) to determine the character of this climate transition. We identified asynchronous shifts in long‐term means and the pacing and amplitude of shorter‐term climate variability, between regions and between climate proxies. Early changes in Antarctic glaciation and Southern Hemisphere ocean properties occurred even during the mid‐Piacenzian warm period (∼3.264–3.025 Ma) which has been used as an analog for future warming. Increased climate variability subsequently developed alongside signatures of larger Northern Hemisphere ice sheets (iNHG). Yet, some regions of the ocean felt no impact of iNHG, particularly in lower latitudes. Our analysis has demonstrated the complex, non‐uniform and globally asynchronous nature of climate changes associated with the iNHG. Shifting ocean gateways and ocean circulation changes may have pre‐conditioned the later evolution of ice sheets with falling atmospheric pCO2. Further development of high‐resolution, multi‐proxy reconstructions of climate is required so that the full potential of the rich and detailed geological records can be realized. Plain Language Summary: Warm climates of the geological past provide windows into future environmental responses to elevated atmospheric CO2 concentrations, and past climate transitions identify important or sensitive regions and processes. We assessed the patterns of average ocean temperatures and indicators of ice sheet size over hundreds of thousands of years, and compared to shorter‐term variability (tens of thousands of years) during a recent transition from late Pliocene warmth (when CO2 was similar to present) to the onset of the large and repeated advances of northern hemisphere ice sheets referred to as the "ice ages." We show that different regions of the climate system changed at different times, with some changing before the ice sheets expanded. The development of larger ice sheets in the Northern Hemisphere then impacted ocean temperatures and circulation, but there were many regions where no impacts were felt. Our analysis highlights regional differences in the timing and amplitudes of change within a globally‐significant climate transition as well as in response to the current atmospheric CO2 concentrations in our climate system. Key Points: The "stable" warm late Pliocene ∼3.3–3.1 million years ago was a time of climate transition, especially in the southern hemisphereOcean temperatures and ice sheets evolved asynchronously 3.3–2.4 Ma during the onset and intensification of Northern Hemisphere GlaciationClimate variability evolved in complex, non‐uniform ways, most strongly expressed in northern mid‐latitude sea‐surface temperature records [ABSTRACT FROM AUTHOR]

This study analyzed the macro- and microphysical response characteristics of a typical multicell hailstorm after seeding on 27 April 2019 in Weining, China, using X-band dual-polarization radar (YLD1-D) data. An improved X-pol hydrometeor identification algorithm was employed for hydrometeor identification. According to the diffusion of the seeding agents, the seeded hailstorm was graded into three study regions, and the evolution of the seeded hailstorm was divided into four periods. The response characteristics of the seeded hailstorm in each region and period were compared and analyzed. The results show that 1) macroscopically, the decrease in the reflectivity and the height of strong echo mainly occurred in the seeded period, whereas the decrease in the echo top and the height of the storm was mainly in the postseeded period; the echo height variation of the unseeded hailstorm is obviously different from that of the seeded hailstorm; and 2) from the microscopic perspective, the decrease in low-density graupel and supercooled water and the increase in ice crystals and aggregates in the seeded region mainly occurred in the seeded period, which was consistent with the time required for the "benefit competition" after the silver iodide completed nucleation. When compared with the seeded region, the hydrometeors in the unseeded region had an opposite trend (or an in-phase trend with an obviously lower changing rate), which further indicated the impact of the artificial ice nuclei on microphysical processes in the seeded region. For hailstorms with a high content of supercooled droplets and graupel, the key mechanisms of hail suppression are "cloud water glaciation," "beneficial competition," and "early rainout." [ABSTRACT FROM AUTHOR]

The investigation of deformations in Quaternary deposits holds primary importance in understanding recent geological history and natural hazards in highly populated areas, such as the Po Plain. While civil excavations and trenches possess the potential to be pivotal in identifying and characterizing these deformations, they often remain underused due to the stringent regulation framework and timetables governing civil construction works. In this study, we demonstrate how digital photogrammetry and digital outcrop modelling (DOM) are useful techniques for obtaining a permanent digital representation of a trench situated in Castelletto Ticino (Po Plain–Southern Alps transition). This trench exhibits Holocene deformational structures: (i) an overall tilting of sedimentary deposits towards the SW; (ii) folds with a NE–SW trend; (iii) slumping and other soft-sediment deformations structures; and (iv) reverse faults with NE–SW and NW–SE directions. Using radiocarbon and archeological dating, we are able to confidently constrain the age of these deformations to between 8760 and 400 years BC, suggesting recent tectonic activity related to buried thrust faults. [ABSTRACT FROM AUTHOR]

The White River Badlands (WRB) of South Dakota record eolian activity spanning the late Pleistocene through the latest Holocene (21 ka to modern), reflecting the effects of the last glacial period and Holocene climate fluctuations (Holocene Thermal Maximum, Medieval Climate Anomaly, and Little Ice Age). The WRB dune fields are important paleoclimate indicators in an area of the Great Plains with few climate proxies. The goal of this study is to use 1 m/pixel-resolution digital elevation models from drone imagery to distinguish Early to Middle Holocene parabolic dunes from Late Holocene parabolic dunes. Results indicate that relative ages of dunes are distinguished by slope and roughness (terrain ruggedness index). Morphological differences are attributed to postdepositional wind erosion, soil formation, and mass wasting. Early to Middle Holocene and Late Holocene paleowind directions, 324°± 13.1° (N = 7) and 323° ± 3.0° (N = 19), respectively, are similar to the modern wind regime. Results suggest significant landscape resilience to wind erosion, which resulted in preservation of a mosaic of Early and Late Holocene parabolic dunes. Quantification of dune characteristics will help refine the chronology of eolian activity in the WRB, provide insight into drought-driven landscape evolution, and integrate WRB eolian activity in a regional paleoenvironmental context. [ABSTRACT FROM AUTHOR]

Pleistocene climate oscillations had a dramatic impact on the distribution of temperate ectothermic organisms. These range fluctuations plausibly have left a footprint on the species' genetic structure which is linked with modelled paleoclimatic conditions, allowing us to infer which environmental factors shaped the evolutionary history of Sand lizards. In this study, we evaluated the patterns of niche diversification of Lacerta agilis in Eurasia, based on mitochondrial DNA analyses and ecological niche models. The lineage of Sand lizards evolved 3.8-1.8 Mya, being the most basal in the east-Caucasian subclade, with eight mitochondrial subclades separated into two groups. These groups represent two independent waves of expansion from the ancestral region constituted by the Caucasus and the adjacent northern plains to the Paleartic. Paleoclimatic models suggested a high instability of the range of this lineage in the last 3 Mya, with niche contractions during the colder glacial periods and expansions following the glacier retreat. This suggested an allopatric diversification process, with subspecies boundaries upon secondary contact maintained by competitive interactions, at least between closely related pairs. The great mountain systems of the Mediterranean Peninsulas constituted stable refugia during the Pliocene-Pleistocene cycles, favouring the evolution of endemic subclades. These montane subclades have higher mitochondrial diversity than those that occur in the plains. However, the Pyrenean endemic L. agilis garzoni is exception possibly due to the occupation of a very small refugium during the recent glacial phases. [ABSTRACT FROM AUTHOR]

The oldest known hominin remains in Europe [~1.5 to ~1.1 million years ago (Ma)] have been recovered from Iberia, where paleoenvironmental reconstructions have indicated warm and wet interglacials and mild glacials, supporting the view that once established, hominin populations persisted continuously. We report analyses of marine and terrestrial proxies from a deep-sea core on the Portugese margin that show the presence of pronounced millennial-scale climate variability during a glacial period ~1.154 to ~1.123 Ma, culminating in a terminal stadial cooling comparable to the most extreme events of the last 400,000 years. Climate envelope-model simulations reveal a drastic decrease in early hominin habitat suitability around the Mediterranean during the terminal stadial. We suggest that these extreme conditions led to the depopulation of Europe, perhaps lasting for several successive glacial-interglacial cycles. [ABSTRACT FROM AUTHOR]

Recent observations confirm the Indo-Pacific Little Tern Sternula albifrons sinensis has been extending its breeding range in Western Australia in recent years, following a pattern documented in other tern and noddy species on the western coast of Australia. Nesting Indo-Pacific Little Terns have been recorded annually as far south as North West Cape since 2016. A similar southward shift in breeding range may have occurred during the last interglacial period and it is hypothesised that Little Terns isolated at the Houtman Abrolhos Islands during the following glacial period gave rise to the Australian Fairy Tern Sternula nereis nereis. The Australian Fairy Tern subsequently colonised the continental shelf from Dampier, Western Australia to the south-eastern states and then New Zealand as sea levels rose again during the Holocene. The two former sibling species are now sympatric between Dampier and North West Cape and interbreeding and hybridisation have the potential to occur in that area. Most jurisdictions require populations to be defined at the species or subspecies level in order to be listed and managed as threatened. However, relying on such taxonomic criteria has the potential to obscure the management of threats faced by each inter-breeding population unit. Approaches that identify and protect the sub-structure of superspecies and meta-populations might be more effective in the longer term. This contribution documents a breeding range extension of the Indo-Pacific Little Tern Sternula albifrons sinensis in Western Australia, following a pattern documented in other tern and noddy species. It also discusses the overlap and relationship with the closely related Australian Fairy Tern Sternula nereis nereis and relevant conservation implications. [ABSTRACT FROM AUTHOR]

Glacial diamictite may provide important information on paleoenvironment and average composition of the upper continental crust (UCC). In this study, we report sedimentary facies, petrological and geochemical characteristics of Neoproterozoic diamictite from a profile of the Luoquan Formation on the southern margin of the North China Block (NCB). Upwards the sampling profile, lithostratigraphic strata vary from massive diamictite with poorly sorted carbonate gravels to laminated diamictite with small gravels of terrestrial detrital materials. Along the profile, CaO-MgO-LOI-Sr values decrease with the increase of SiO2-Al2O3-K2O contents. All these petrological and geochemical variations indicate a change from lodgement till deposition in the proximal of ice sheet to ice-rafting deposition in glacial-marine environment with less dolomite to supply their source. Together with previous studies on diamictite from other outcrops on the NCB, the deposition of Luoquan diamictite reflects that the glaciation on the NCB vanished and the ice-rafting effect weakened with glacial transgression process. In addition, significant co-variations of various elements with La and Al2O3 confirm the significant conservation of most analyzed elements during the sedimentary processes to produce diamictite. [ABSTRACT FROM AUTHOR]

At the end of the last glacial period in the northern hemisphere, meltwater from receding ice sheets accumulated into large proglacial lakes, potentially limiting postglacial afforestation. We explored whether former islands of proglacial Lake Ojibway (Canada) (hilltops in the current landscape) could have acted as migration outposts and thus accelerated the postglacial migration. We extracted sediments from two small lakes located on "paleo-islands" and used XRF to detect changes in soil erosion and vegetation biomass. We also used plant macro-remains and wood charcoal to determine if (and which) tree species colonized the sites and to detect local fire events. Organic sediment accumulation started around 9657 and 9947 cal. yr BP at Lakes Perché and Despériers, respectively, before the level of Lake Ojibway started to decrease and liberate parts of the studied landscape ca 9400 cal. yr BP. Lithogenic elements (Ti, K, Sr, Fe, Zr, and Rb) decreased between the beginning of organic sediment accumulation and 8800–8700 cal. yr BP, indicating reduced soil erosion, possibly due to soil stabilization by vegetation. Then, the S/Ti ratio, a proxy of organic matter increased around 8800 and 8400 cal. yr BP. The earliest tree macro-remains (Larix laricina and Pinus spp.) were found between 9850 and 9500 cal. yr BP. Local fires were detected around 9820 and 8362 cal. yr BP. Early afforestation occurred on the islands of Lake Ojibway, 200 and 450 years before its level started to decrease, confirming that some islands acted as migratory outposts accelerating postglacial migration. [ABSTRACT FROM AUTHOR]

Simple Summary: The Siberian ibex has a wide distribution, spanning various mountainous regions and cold deserts in countries like India, China, Pakistan, Kazakhstan, Tajikistan, Russia, and Mongolia. Our study specifically examined the Himalayan ibex, which is an edge population of Siberian ibex found in India. Through genomic analysis, we discovered that the Himalayan ibex evolved as a distinct lineage after separating from the main population around 100,000 years ago, due to geographical isolation. By studying the region's past geography using paleo-climatic models and deep sequencing data, we observed significant transformations, including high mountains and deep valleys, particularly in the Pamir range, likely played a significant role in the divergence and independent evolution of the Himalayan ibex, after experiencing two historic genetic bottlenecks. Based on our findings, we propose prioritizing the Himalayan ibex as a unique phylogenetic species and advocate for its conservation attention and taxonomic revision. Furthermore, we hope that our research will inspire collaborative efforts and discussions among different countries to address the conservation and management of ibex populations worldwide. Pleistocene glaciations had profound impact on the spatial distribution and genetic makeup of species in temperate ecosystems. While the glacial period trapped several species into glacial refugia and caused abrupt decline in large populations, the interglacial period facilitated population growth and range expansion leading to allopatric speciation. Here, we analyzed 40 genomes of four species of ibex and found that Himalayan ibex in the Pamir Mountains evolved independently after splitting from its main range about 0.1 mya following the Pleistocene species pump concept. Demographic trajectories showed Himalayan ibex experienced two historic bottlenecks, one each c. 0.8–0.5 mya and c. 50–30 kya, with an intermediate large population expansion c. 0.2–0.16 mya coinciding with Mid-Pleistocene Transitions. We substantiate with multi-dimensional evidence that Himalayan ibex is an evolutionary distinct phylogenetic species of Siberian ibex which need to be prioritized as Capra himalayensis for taxonomic revision and conservation planning at a regional and global scale. [ABSTRACT FROM AUTHOR]

Vertically accreted, cyclic tidal rhythmites—laminated, fine-grained sandstones, siltstones and mudstones—occur in the late Cryogenian glaciogenic Elatina Formation (ca 635 Ma) and early Cryogenian Sturt Formation (ca 660 Ma) in the South Flinders Ranges region of the Adelaide Rift Complex within the Adelaide Superbasin, and in Cryogenian strata from Nicholson 2 drill hole in the eastern Officer Basin, South Australia. The rhythmites provide insights into Cryogenian littoral environments. The Elatina rhythmite was deposited during an interstadial and the Sturt rhythmite during early glacial advance, whereas the Nicholson 2 rhythmite is assigned to interglacial beds. The resultant raised sea levels and drowned valleys provided the tidal inlets, ebb-tidal deltas, estuaries and fjords favouring rhythmite deposition. The rhythmites display semidiurnal and diurnal (lunar day) tidal laminae grouped in fortnightly neap–spring cycles and record the semiannual tide. Periods of 26.2 ± 0.9 neap–spring cycles displayed by the Elatina rhythmite and ∼27 neap–spring cycles by the Nicholson 2 rhythmite mark the non-tidal annual variation of sea level, which results from seasonal surface winds and changes in atmospheric pressure and temperature acting on the waters of marine shelves and marginal seas. The strong annual signals and absence of dropstones in the Elatina and Nicholson 2 rhythmites indicate that respective marine shelves and marginal seas were ice-free during rhythmite deposition. The Sturt rhythmite, by contrast, shows a weak annual period of ∼27 neap–spring cycles and contains dropstones and till pellets, indicating that the adjacent marine shelf and sea were largely ice-covered. Paleotidal data for the Elatina rhythmite have illuminated Earth's late Cryogenian paleorotation and the Moon's orbit, and paleomagnetic studies of the Elatina rhythmite indicated a low paleolatitude for late Cryogenian glaciation. Contrary to recent modelling by others, strong tides existed at shallow-water continental margins during Cryogenian glaciations. Cyclic tidal rhythmites are associated with early and late Cryogenian (ca 660 and ca 635 Ma) glaciogenic successions and interglacial beds in South Australia. Rhythmite deposition occurred when raised sea levels provided the coastal environments favouring rhythmite deposition. The rhythmites display semidiurnal and diurnal tidal laminae grouped in fortnightly cycles, and record the semiannual tide and the non-tidal annual variation of sea level. Strong tides existed at shallow-water continental margins during early and late Cryogenian low-latitude glaciations and the interglacial interval. [ABSTRACT FROM AUTHOR]

The Pliensbachian–Toarcian transition was characterised by a drastic turnover from a cool climate to a period of rapid global warming. While the warming associated with the Early Toarcian Oceanic Anoxic Event is rather well-studied, the cause, intensity and extent of the preceding cooling in the late Pliensbachian are still discussed. Occurrences of glendonite play an important role in this debate, since glendonite is a pseudomorph after the cryophilic carbonate mineral ikaite. This study describes the first glendonite-bearing carbonate concretions from South Germany (Buttenheim clay pit, northern Franconian Alb), which represent the southernmost glendonite occurrence in the late Pliensbachian documented so far. Based on petrographical and sedimentological investigations as well as stable isotope analyses it is concluded that a low temperature was the main factor for ikaite formation in the studied section, suggesting that the late Pliensbachian cooling had a more far-reaching impact on the temperature of the European epicontinental sea than previously assumed. To explain the low temperatures required for ikaite precipitation, a model for the sea-ice driven formation of cold bottom-water masses on the continental shelf is proposed. The occurrence of several layers containing reworked hiatus concretions in the studied outcrop is interpreted as the result of recurrent sea-level falls caused by multiple glacial pulses characterising the overall cool climate in the late Pliensbachian. [ABSTRACT FROM AUTHOR]

On the southwest cape of the Congo craton, a subtropical carbonate bank the size of Greenland was heavily glaciated during two Cryogenian panglacial episodes spaced 10–20 Myr apart. In NW Namibia, the bank underwent crustal stretching with resultant Aegean Sea-type topography during the older and longer Sturtian glaciation (717–661 Ma). This is indicated by angular discordance between glacial and preglacial strata and diamictites sourced from all older units, including crystalline basement. In contrast, the bank was flat-topped and underwent broad thermal subsidence during Marinoan glaciation (646 ± 5–635 Ma), attested by stratal parallellism and diamictites sourced from ≤100 m stratigraphic depth. However, ≥2.0 km of relief existed on the Marinoan continental slope, where most glacial erosion and accumulation occurred. The average rates of Marinoan erosion (2.55–6.80 m/Myr, n = 190) and accumulation (2.65–7.07 m/Myr, n = 211) are indistinguishable, implying that the location in a continental promontory did not bias erosion over accumulation. The average accumulation rates for the Sturtian and Marinoan, scaled for different averaging times, including Marinoan uncertainty, are 3.95–4.93 m/Myr (n = 183) and 2.65–7.07 m/Myr (n = 190), respectively, suggesting that a Marinoan glacioeustatic coastal escarpment substituted for rift-related Sturtian basin-and-range topography. These slow rates, comparable to long-term pre-Quaternary accumulation rates on existing abyssal plains, reconcile glacial sedimentology with the feeble hydrologic cycle of snowball Earth. [ABSTRACT FROM AUTHOR]