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Aim: In northern environments, periods of isolation during Pleistocene glaciations and subsequent recolonization and secondary contact have had a significant influence on contemporary diversity of many species. The recent advent of high‐resolution genomic analyses allows unprecedented power to resolve genomic signatures of such events in northern species. Here, we provide the highest resolution genomic characterization of Atlantic salmon in North America to date to infer glacial refugia and the geographic scales of post‐glacial secondary contact. Location: North America. Taxon: Atlantic salmon, Salmo salar. Methods: Samples were collected for 5455 individuals from 148 populations, encompassing the majority of the Atlantic salmon's native range in North America, from Labrador to Maine. Individuals were genotyped using a 220K single nucleotide polymorphism array aligned to the Atlantic salmon (Salmo salar) genome. Spatial genetic structure (principal component analysis, k‐means clustering, admixture) was evaluated in conjunction with genomic comparisons of these identified lineages to infer the refugia during the last glacial maximum and regions of secondary contact following recolonization. Results: Spatial genomic analyses identified three phylogeographic groups, consistent with the northward recolonization from two southern glacial refugia in North America (a western Maritime lineage and an eastern Newfoundland and Labrador lineage), with subsequent differentiation of the eastern lineage into two separate groups. Secondary contact among these North American groups was observed within the northern Gulf of St. Lawrence, and evidence of trans‐Atlantic secondary contact was detected within the eastern Newfoundland and Labrador lineage. Comparison of groups from insular Newfoundland with those from mainland Labrador suggests genomic regions displaying high differentiation were characterized by elevated European admixture, suggesting a possible role of European secondary contact in population divergence. Main Conclusions: These findings present the first evidence suggesting that genomic diversity in extant North American Atlantic salmon populations has resulted from allopatric isolation in two glacial refugia followed by both regional and trans‐Atlantic recolonization and secondary contact and demonstrate the power of genomic tools to resolve historical drivers of diversity in wild populations. [ABSTRACT FROM AUTHOR]

We investigate the position and intensity changes of the Intertropical Convergence Zone (ITCZ) over Asia (50°E−135°E) relative to the preindustrial period annually and seasonally during the Last Interglacial (LIG), Last Glacial Maximum (LGM), and mid‐Holocene (MH) using available models from phases 3 and 4 of the Paleoclimate Modeling Intercomparison Project. The multi‐model mean shows that the June–July–August ITCZ variations generally dominate the annual changes. The Asian ITCZ shifts northward over western Asia and southward over the eastern side in both the LIG and MH, and the opposite occurs in the LGM. Its intensity varies with longitude similarly for the LIG and MH and generally weakens in the LGM. Precipitation changes associated directly with ITCZ indices are primarily caused by the dynamic term in the LIG and MH, while both dynamic and thermodynamic terms play roles in the LGM, with major contributions from the convergence components. Plain Language Summary: As an intense rain belt, the Intertropical Convergence Zone (ITCZ) has an important influence on the regional climate, particularly over Asia. However, its future and past behaviors remain unclear. Based on multi‐model experiments, we investigate Asian ITCZ changes in location and intensity during the past three typical periods: the interglacial periods of the Last Interglacial and the mid‐Holocene and the glacial period of the Last Glacial Maximum. The Asian ITCZ overall strengthens and regionally moves northward over the western part and southward over the eastern part during the two interglacial periods relative to its preindustrial state, which are generally opposite to the position and intensity changes in the glacial period. These ITCZ changes are directly caused by uneven precipitation changes, which are dominated by atmospheric circulation changes during interglacial periods and additionally contributed from water vapor content changes during glacial periods, primarily through the vertical motion of air. Key Points: Asian Intertropical Convergence Zone (ITCZ) shifts northward over western Asia and southward over the eastern side in Last Interglacial (LIG) and mid‐Holocene (MH), and the opposite occurs in Last Glacial Maximum (LGM)Asian ITCZ intensity varies with longitude similarly for LIG and MH, while it weakens during LGMDynamic term dominates the ITCZ‐related precipitation changes in LIG and MH, while both dynamic and thermodynamic terms play roles in LGM [ABSTRACT FROM AUTHOR]

This paper explores the resizing, reshaping and connectivity of islands by examining ongoing relations between land and sea in the context of the Channel Island of Guernsey. Ideas of materiality, temporality and vertical depth are employed to explore how contemporary tides and past sea‐level change impact island–island connections, and island–mainland connections between Guernsey and France. By focusing on the littoral zone as a space of encounter between land and sea, the paper explores some of the processes that challenge the notion of an island having fixed edges, emphasising the island's shape and size as always in flux. The paper then explores how tides alternatively reveal and hide material structures such as rocks and causeways, making the underwater scape temporally visible and differently accessible as an extension of land. It enables connections to be made and remade. This is demonstrated through the example of Guernsey and the tidal island of Lihou. The paper subsequently considers these ideas in the context of Quaternary sea‐level change. The land known as Guernsey alternated between literal island surrounded by water, and a steep‐sided plateau on the Normanno‐Breton plain, coinciding with interglacials and glacials. This connection is referred to as geologic. I argue that by acknowledging Guernsey's former visible connection with France, lack of contemporary visibility in the underwater scape does not render this a disconnection. Rather, the geologic, as further evidenced in the contemporary natural and built environment of Guernsey, continues through an underwater scape. It reappears in other Channal Islands and France, demonstrating ongoing connections at a land–sea–geologic interface. The paper argues for geology as a form of vertical depth. It calls for greater consideration of the geologic in the human geographical study of islands. [ABSTRACT FROM AUTHOR]

The last glacial period is known to have greatly influenced the demographic history of temperate forest trees, with important range contractions and post‐glacial expansions that led to the formation of multiple genetic lineages and secondary contact zones in the Northern Hemisphere. These dynamics have been extensively studied for European and North American species but are still poorly understood in other temperate regions of rich biodiversity such as the Caucasus. Our study helps filling that gap by deciphering the genomic landscapes of F. orientalis across the South Caucasus. The use of genome‐wide data confirmed a past demographic history strongly influenced by the Last Glacial Maximum, revealing two disjunct glacial refugia in the Colchis and Hyrcanian regions. The resulting patterns of genetic diversity, load and differentiation are not always concordant across the region, with genetic load pinpointing the location of the glacial refugia more efficiently than genetic diversity alone. The Hyrcanian forests show depleted genetic diversity and substantial isolation, even if long‐distance gene flow is still present with the main centre of diversity in the Greater Caucasus. Finally, we characterize a strong heterogeneity of genetic diversity and differentiation along the species chromosomes, with noticeably a first chromosome showing low diversity and weak differentiation. [ABSTRACT FROM AUTHOR]

Understanding spatial patterns of biodiversity within the context of long‐term climatic shifts is of high importance, particularly in the face of contemporary climate change. In comparison to aboveground taxa, subterranean organisms respond to changing climates with generally much lower dispersal and recolonization potential, yet possible persistence in refugial groundwater habitats under ice‐shields. However, knowledge on general and geographically large‐scale effects of glaciation on contemporary groundwater biodiversity patterns is still very limited. Here, we tested how Late Pleistocene glaciation influenced the diversity and distribution of 36 groundwater amphipod species in Alpine and peri‐Alpine regions, characterized by extensive glaciation cycles, and how its legacy explains contemporary diversity patterns. We based our analysis on an unprecedented density of ~ 1000 systematic sampling sites across Switzerland. Using presence–absence data, we assessed biodiversity and species' ranges, and calculated for each site within‐catchment distance to the Last Glacial Maximum (LGM) glacier extent. We then applied a sliding window approach along the obtained distance gradient from LGM ice‐covered to ice‐free sites to compute biodiversity indices reflecting local richness, regional richness, and differentiation, respectively. We found a strong signal of the LGM ice extent on the present‐day distribution of groundwater amphipods. Our findings revealed pronounced species turnover and spatial envelopes of individual species' occurrences in formerly ice‐covered, ice‐free, or transitional zones, respectively. While local richness remained constant and low along the LGM distance gradient, groundwater communities in LGM ice‐covered areas were more similar to each other and had lower gamma diversities and decreased occurrence probabilities per sliding window compared to communities in Pleistocene ice‐free areas. These results highlight the significant impact of Pleistocene glaciation on shaping biodiversity patterns of subterranean communities and imprinting contemporary distribution of groundwater organisms. [ABSTRACT FROM AUTHOR]

Knowledge of the behaviour of marine‐based ice sheets during times of climatic warming, such as the last deglaciation, provides important information to understand how ice sheets respond to external forcing. We analysed swath bathymetric and acoustic sub‐bottom profiler data from Wrigley Gulf on the western Amundsen Sea shelf, West Antarctica, to identify glacial features and reconstruct past changes in the extent of the West Antarctic Ice Sheet (WAIS) and ice flow directions. Glacial bedforms mapped within a bathymetric cross‐shelf trough include features showing cross‐cutting and overprinting relationship and indicate changes in ice‐flow orientation. Here, we distinguish at least two phases of different ice‐flow patterns on the Wrigley Gulf shelf. During the earlier phase, seaward ice stream flow on the inner shelf was deflected towards the east due to the existence of an ice dome on the middle‐outer continental shelf. Retreat of grounded ice towards the centre of this dome is indicated by the asymmetric cross profile of recessional moraines mapped on the middle shelf. The later glaciation phase was characterized by fast, NNW‐directed ice flow across the shelf along a broad front and subsequent stepwise landward retreat, which is evident from the common occurrence and orientation of mega‐scale glaciation lineations and grounding zone wedges on the middle‐inner shelf. It is uncertain whether the two phases of glaciation recorded on the seafloor occurred during the last and penultimate glacial periods or at different times of the last glaciation. Reliable chronological constraints from sediment cores and additional geomorphological information are needed to understand the cause of the changes in WAIS dynamics reflected by the two ice‐flow phases. [ABSTRACT FROM AUTHOR]

The study of alluvial terraces helps in reconstructing the past geometries of rivers and makes it possible to assess the rate and pattern of fluvial incision and bedrock uplift. The fluctuations of river base levels are particularly variable and complex during the Late Quaternary in the lower course of rivers due to the interplay of responses to sea‐level fluctuations, tectonics and glacio‐isostasy. In this paper, the geometry and chronology of Manoir Brésil, an outcrop of alluvial terraces of the Lower Seine River, northern France, are investigated through a multidisciplinary study. Fluvial incision during MIS 8 in the Lower Seine in relation to sea‐level drop is recorded by an erosional surface cut into the chalk bedrock. This surface is covered by MIS 7 tidal deposits and then by younger, mostly periglacial colluvium (head). Manoir Brésil is therefore considered to be a chronological equivalent of the nearby, well‐studied Tourville‐la‐Rivière outcrop. The deposits are affected by post‐MIS 7 cryoturbation processes. Based on the local elevation of MIS 7 tidal deposits and erosional surfaces at Manoir Brésil, a minimum bedrock uplift rate of 25–40 m/Ma and an erosion rate of 125 m/Ma during glacial periods can be proposed. A regional correlation of the MIS 8 erosional surface is increasingly deformed by uplift towards the North, making it difficult to correlate the fluvial deposits along the Seine without precise chronological control. We interpret this regional tilt as the result of isostasy rebound after glaciations, consistent with the distribution of the elevations of MIS 5e and MIS 7 marine deposits along the English Channel. [ABSTRACT FROM AUTHOR]

A pre‐Late Wisconsinan, post‐Illinoian, till sheet has long been recognized in north‐central Iowa, but has not been formally recognized or defined until now. Early researchers referred to these deposits as the 'Tazewell', and the term 'Sheldon Creek' was more recently used informally by the Iowa Geological Survey in guidebooks and reports. Recent mapping has extended the eastern margin significantly past previous interpretations. The Sheldon Creek Formation has similar lithologic characteristics to the overlying Alden Member of the Dows Formation, and the two units are distinguished mainly by stratigraphic position. Differentiation from underlying Pre‐Illinoian till units is accomplished using lithology, primarily matrix grain‐size and sand fraction lithology. A suite of 22 radiocarbon ages indicate two distinct, separate groupings within the Sheldon Creek data. These data strongly suggest ice advanced south to 42° N twice, once during Marine Isotope Stage (MIS) 3 and again during late MIS 3 or possibly early MIS 2. The presence of the Laurentide Ice Sheet in northern Iowa during MIS 3 has significant implications for ice sheet reconstructions during this interval. [ABSTRACT FROM AUTHOR]

Glacier‐Like Forms (GLFs) are a subset of ice‐rich landforms known as Viscous Flow Features that populate Mars' mid‐latitudes. GLFs are morphologically similar to terrestrial valley glaciers and are thought to result from the redistribution of water ice from the Martian poles during periods of high obliquity throughout the Amazonian period. Their ages, formation, and evolutionary processes are poorly constrained. We selected the 100 largest GLFs from the most recent GLF population data set, and by analyzing their superimposing crater morphologies and populations, we calculated their Crater Retention Ages (CRAs) and identified any relationships between CRAs, crater morphologies, and GLF geometries. We also organized the crater morphologies into states of degradation based on the understood erosional sequences. 3,630 craters were mapped, which we classified into 15 different crater morphologies. We calculated 98 CRAs, ranging from ∼2.88 Ma to ∼3.5 Ga. On average, GLFs in the southern hemisphere have younger CRAs, higher average slopes, smaller crater populations, and show less variability in crater morphological development than in the northern hemisphere. GLFs with higher mean slopes display less crater morphology variety, suggesting that shallow GLFs experience less reworking than steeper GLFs. We propose that these regional and hemispheric differences are due to a combination of favorable topography and climate conditions, both during and between high obliquity periods. We present several scenarios for the GLFs observed in this study and suggest that the glacial and erosional processes that affect GLF evolution are likely locale‐dependent. Plain Language Summary: Glacier‐Like Forms (GLFs) are ice‐rich landforms located in the mid‐latitudes of Mars and are similar in appearance to valley glaciers found on Earth. They are thought to be a result of the redistribution of water ice from the Martian poles during periods when Mars' axis tilts to a higher angle, exposing the poles to more heat from the sun. We selected the 100 largest glaciers to estimate the age of their surfaces via impact crater counting, to identify impact crater morphologies, and to compare this data to existing data on GLF geometrics. We mapped 3,630 craters, identified 15 different impact crater morphologies, and determined the surface ages of 98 glaciers, which ranged from 2.88 million years to 3.5 billion years old. Our analysis shows that glaciers with lower than average slopes have impact craters with a wider range of morphologies than glaciers with higher average surface slopes. Overall we find that glaciers in the southern hemisphere of Mars have young surface ages, and fewer and less developed craters compared with the northern hemisphere. We suggest different regional processes are occurring across Mars, with some areas favoring resurfacing processes more than others, and that glacier surface evolution is specific to the local environment. Key Points: The surface ages, crater morphologies, and metrics of the 100 largest Glacier‐Like Forms (GLFs) on Mars were explored to determine any trendsSurface ages range from 3430 to 2.88 Ma with 15 different crater morphologies. Slope exerts a substantial control on crater morphology developmentResurfacing processes occurring in certain regions of Mars have a greater effect on GLF surfaces than in others [ABSTRACT FROM AUTHOR]

To date, the most complete paleolake‐level reconstructions for the late Pleistocene water bodies that once occupied the Dead Sea depression have been based on the combination of dating of lake sediments and terrestrial materials. However, despite these major accomplishments, there is still limited spatial control regarding the water levels, suggesting some degree of uncertainty concerning the magnitude and rate of lake‐level changes. Here, we re‐examine the late Pleistocene lake‐level changes in the Dead Sea during the transition from paleolake Lisan to the present‐day Dead Sea. We rely on systematic dating of fossil stromatolites including 84 radiocarbon and 15 U‐series ages, stable‐isotope measurements, paleobiology, high‐resolution topography, and numerical modeling to assess lake‐level changes. Our results indicate that the highstand of paleolake Lisan was of shorter duration and the transition between Lake Lisan and the Dead Sea occurred at least 5 Kyrs earlier than previously indicated. By refining the timeline and accuracy of lake‐level positions during the transition paleolake Lisan—Dead Sea, our study offers new insights into the regional and local paleo‐climatic conditions during the last glacial period in this region. Plain Language Summary: Index points, reflecting the unique position of the water levels in space and time, have been broadly used in marine realms to reconstruct past sea‐level changes. Here we study lake‐level variations using index points based on geomorphic and biological markers collected along the western and eastern coasts of the Dead Sea. Previous studies indicate that during the last glacial period (20–30 ka), the Dead Sea depression was filled by paleolake Lisan, which lasted 10 Kyrs. As it dried, dozens of paleo‐shorelines remained etched in the landscape. Lake level index points estimated from 99 radiometric ages in these paleo‐shorelines suggest that Lisan's highstand was shorter and the transition to the Dead Sea occurred 5 Kyrs earlier than previously thought. These novel results suggest an initial and wet period followed by drier conditions, altering the regional paleo‐climatic narrative during the last glacial period. Key Points: Lake paleo‐shorelines and fossil stromatolites are used to reconstruct lake‐level changes during the transition paleolake Lisan‐Dead SeaFossil stromatolites were dated using radiocarbon and U‐series applying temporal and vertical correctionsThe transition between paleolake Lisan and the Dead Sea occurred ∼5 Kyrs earlier than estimated by previous reconstructions [ABSTRACT FROM AUTHOR]

Reconstruction of the seawater carbonate system is essential for an improved understanding of glacial‐interglacial oceanic carbon cycling and climate change. However, continuous high‐resolution ocean carbonate chemistry data are generally lacking for the Plio‐Pleistocene. Here, we present a deep Pacific carbonate ion saturation state (Δ[CO32−]) record spanning the last 5.1 Myr, reconstructed from the size‐normalized shell weight of planktonic foraminifer in the western tropical Pacific. Deep Pacific Δ[CO32−] has been modulated primarily by orbital obliquity since 5.1 Ma, during which it has exhibited in‐phase behavior with the 40‐Kyr obliquity cycle. Significantly, the amplitude of the 40‐Kyr Δ[CO32−] cycles has responded linearly to obliquity forcing throughout the Plio‐Pleistocene, independent of the late Pliocene intensification of Northern Hemisphere glaciation. We speculate that the obliquity signal in the deep Pacific Δ[CO32−] record reflects an ocean‐atmosphere circulation feedback mediated by migration of the Southern Hemisphere Westerlies. Plain Language Summary: The ocean has played an important role in controlling glacial‐to‐interglacial atmospheric pCO2 variation through changes in its carbon inventory. To decipher the patterns and drivers of the oceanic carbon cycle and climate change through glacial cycles, we provide a continuous Plio‐Pleistocene deep Pacific carbonate ion saturation state (Δ[CO32−]) at orbital time scales. The deep PacificΔ[CO32−] has been modulated by orbital forcing since 5.1 Ma, a time interval during which it has exhibited in‐phase behavior with the 40‐Kyr obliquity cycle as well as a linear response of Δ[CO32−] amplitude to obliquity range. We speculate that Plio‐Pleistocene glacial cycles of the deep Pacific carbon storage were linked to variation in Southern Hemisphere upwelling rates yoked to meridional migration of the Westerlies. Key Points: Deep Pacific Δ[CO32−] has been modulated primarily by orbital obliquity since 5.1 Ma40‐Kyr Δ[CO32−] cycles were in‐phase with and responded linearly to 40‐Kyr band obliquity forcingPlio‐Pleistocene glacial cycles of deep Pacific carbon storage were linked to meridional migration of the Southern Hemisphere Westerlies [ABSTRACT FROM AUTHOR]

Climate contrasts across drainage divides, such as orographic precipitation, are ubiquitous in mountain ranges, and as a result, mountain topography is often asymmetric. During glacial periods, these climate gradients can generate asymmetric glaciation, which may modify topographic asymmetry and drive divide migration during glacial‐interglacial cycles. Here we quantify topographic asymmetry caused by asymmetric glaciation and its sensitivity to different climate scenarios. Using an analytical model of a steady‐state glacial profile, we find that the degree of topographic asymmetry is primarily controlled by differences in the equilibrium line altitude across the divide. Our results show that glacial erosion can respond to the same climate asymmetry differently than fluvial erosion. When there are precipitation differences across the divide, glacial erosion produces greater topographic asymmetry than fluvial erosion, all else equal. These findings suggest that glaciations may promote drainage reorganization and landscape transience in intermittently glaciated mountain ranges. Plain Language Summary: In mountainous regions, the amount of rain, snow, and ice that falls and builds up often varies from one side of a mountain to the other. Over thousands to millions of years, these variations can make the length and steepness of the mountain sides differ, too. When glaciers form during ice ages, they can make this asymmetry in the topography even more pronounced. Our study looks at how glaciers affect the landscape and how glaciers and landscapes change in different climate conditions. Using a computer model, we discovered that the landscape becomes even more asymmetric when it is shaped by glaciers compared to when it is shaped by rivers. Our findings suggest that glaciers can cause landscapes to constantly change between ice ages. Key Points: We quantify topographic asymmetry caused by asymmetric glaciationGlacial erosion causes greater topographic asymmetry than fluvial erosion all else equalGlacial‐interglacial cycles can cause divide migration [ABSTRACT FROM AUTHOR]

Amaranthaceae s.l. is a widely distributed family consisting of over 170 genera and 2000 species. Previous molecular phylogenetic studies have shown that Amaranthaceae s.s. and traditional Chenopodiaceae form a monophyletic group (Amaranthaceae s.l.), however, the relationships within this evolutionary branch have yet to be fully resolved. In this study, we assembled the complete plastomes and full‐length ITS of 21 Amaranthaceae s.l. individuals and compared them with 38 species of Amaranthaceae s.l. Through plastome structure and sequence alignment analysis, we identified a reverse complementary region approximately 5200 bp long in the genera Atriplex and Chenopodium. Adaptive evolution analysis revealed significant positive selection in eight genes, which likely played a driving role in the evolution of Amaranthaceae s.l., as demonstrated by partitioned evolutionary analysis. Furthermore, we found that about two‐thirds of the examined species lack the ycf15 gene, potentially associated with natural selection pressures from their adapted habitats. The phylogenetic tree indicated that some genera (Chenopodium, Halogeton, and Subtr. Salsolinae) are paraphyletic lineages. Our results strongly support the clustering of Amaranthaceae s.l. with monophyletic traditional Chenopodiaceae (Clades I and II) and Amaranthaceae s.s. After a comprehensive analysis, we determined that cytonuclear conflict, gene selection by adapted habitats, and incomplete lineage sorting (ILS) events were the primary reasons for the inconsistent phylogeny of Amaranthaceae s.l. During the last glacial period, certain species within Amaranthaceae s.l. underwent adaptations to different environments and began to differentiate rapidly. Since then, these species may have experienced morphological and genetic changes distinct from those of other genera due to intense selection pressure. [ABSTRACT FROM AUTHOR]

The mountains in the Atlantic Forest domain are environments that harbor a high biodiversity, including species adapted to colder climates that were probably influenced by the climatic variations of the Pleistocene. To understand the phylogeographic pattern and assess the taxonomic boundaries between two sister montane species, a genomic study of the butterflies Actinote mantiqueira and A. alalia (Nymphalidae: Acraeini) was conducted. Analyses based on partial sequences of the mitochondrial gene COI (barcode region) failed to recover any phylogenetic or genetic structure discriminating the two species or sampling localities. However, single nucleotide polymorphisms gathered using Genotyping‐by‐Sequencing provided a strong isolation pattern in all analyses (genetic distance, phylogenetic hypothesis, clustering analyses, and FST statistics) which is consistent with morphology, separating all individuals of A. alalia from all populations of A. mantiqueira. The three sampled mountain ranges where A. mantiqueira populations occur—Serra do Mar, Serra da Mantiqueira, and Poços de Caldas Plateau—were identified as three isolated clusters. Paleoclimate simulations indicate that both species' distributions changed according to climatic oscillations in the Pleistocene period, with the two species potentially occurring in areas of lower altitude during glacial periods when compared to the interglacial periods (as the present). Besides, a potential path between their distribution through the Serra do Mar Mountain range was inferred. Therefore, the Pleistocene climatic fluctuation had a significant impact on the speciation process between A. alalia and A. mantiqueira, which was brought on by isolation at different mountain summits during interglacial periods, as shown by the modeled historical distribution and the observed genetic structure. [ABSTRACT FROM AUTHOR]

The Yunnan‐Guizhou Plateau (YGP) is characterized by the distinctive isolated habitat of the limestone Karst Islands and features the Wumeng Mountains, which divide the YGP into the two Plateaus of Yunnan and Guizhou. This study aimed to assess the effects of geographic isolation and past climate fluctuation on the distribution of flora in the YGP. To achieve this, we carried out the phylogeographical pattern and genetic structure based on chloroplast and nuclear ribosomal DNA sequence in relation to past (Last Glacial Maximum) and present distributions based on ecological niche modeling for Morella nana, an important wild plant resource and endemic to the YGP once considered a vulnerable species. The results suggest that the genetic and chlorotype network structures of M. nana are divided into at least two groups: cpDNA chlorotype H2 (or dominant nrDNA haplotypes h1 and h2), distributed primarily to the east of the Wumeng Mountains, and cpDNA chlorotypes H1 and H3–H10 (or dominant nrDNA haplotype h2 and h3), distributed to the west of the Wumeng Mountains. A deep genetic split was noted within the two groups to reach 25 steps, especially for the cpDNA fragment variation. This east–west divergence reveals the existence of a natural geographical isolation boundary in the form of the Wumeng Mountains, and supports the existence of at least two glacial refuges during the Quaternary glacial period, along with two genetic diversity center, and at least two large geographic protection units for the important species of M. nana. This study indicates that the phylogeographical pattern of M. nana can be attributed to geographic/environmental isolation caused by the Wumeng Mountains and climate fluctuation during the last glacial maximum, and proposes an effective strategy to protecting this important plant resource. [ABSTRACT FROM AUTHOR]

It has been hypothesized that the Araucaria Forest in southern Brazil underwent expansions in the past, driven either by human groups or by climate fluctuations of the Holocene and Pleistocene. Fossil pollen records of the Paraná pine Araucaria angustifolia, a dominant tree in that forest, provide some insights into when those may have occurred. Still, the timing of those expansions has never been estimated. To infer past range shifts and shed light on their main drivers, we employed next‐generation DNA sequencing (ddRADseq), machine learning, and a comprehensive database of fossil pollen records into a study of historical demographic inference and paleo‐distribution modeling of the Paraná pine. We found that A. angustifolia comprises two populations expanding at different times: one in the Mantiqueira mountain chain, the other in the southern Brazilian plateau. The southern population began to expand during the Last Glacial Period ~ 70 kya, long before human arrival in South America. Still, genetic analyses support that humans later impacted this population, resulting in lower genetic diversity, higher inbreeding, and high levels of gene flow over large distances with a weak pattern of isolation‐by‐distance. It is possible this resulted from human influence on seed dispersal and germination on the southern Brazilian plateau. The Mantiqueira population, in contrast, expanded only recently (~ 3 kya). This timing coincides with Holocene climatic changes and human settlements established further south, although, to date, there is little archeological evidence of human impact in the Mantiqueira. In addition, multitemporal species distribution models built from a combination of present‐day and pollen records infer a range expansion of the Araucaria Forest during glacial times until the cold humid HS1 event (~ 16 kya), when the forest was most widespread, with no evidence of glacial refugia. The combination of genomic and spatial analyses suggests that both human and climatic controls played a role in the dynamics of the Araucaria Forest. [ABSTRACT FROM AUTHOR]

Aim: Within the intensively‐studied, well‐documented latitudinal diversity gradient, the deep‐sea biodiversity of the present‐day Norwegian Sea stands out with its notably low diversity, constituting a steep latitudinal diversity gradient in the North Atlantic. The reason behind this has long been a topic of debate and speculation. Most prominently, it is explained by the deep‐sea glacial disturbance hypothesis, which states that harsh environmental glacial conditions negatively impacted Norwegian Sea diversities, which have not yet fully recovered. Our aim is to empirically test this hypothesis. Specific research questions are: (1) Has deep‐sea biodiversity been lower during glacials than during interglacials? (2) Was there any faunal shift at the Mid‐Brunhes Event (MBE) when the mode of glacial–interglacial climatic change was altered? Location: Norwegian Sea, deep sea (1819–2800 m), coring sites MD992277, PS1243, and M23352. Time period: 620.7–1.4 ka (Middle Pleistocene–Late Holocene). Taxa studied: Ostracoda (Crustacea). Methods: We empirically test the deep‐sea glacial disturbance hypothesis by investigating whether diversity in glacial periods is consistently lower than diversity in interglacial periods. Additionally, we apply comparative analyses to determine a potential faunal shift at the MBE, a Pleistocene event describing a fundamental shift in global climate. Results: The deep Norwegian Sea diversity was not lower during glacial periods compared to interglacial periods. Holocene diversity was exceedingly lower than that of the last glacial period. Faunal composition changed substantially between pre‐ and post‐MBE. Main conclusions: These results reject the glacial disturbance hypothesis, since the low glacial diversity is the important precondition here. The present‐day‐style deep Norwegian Sea ecosystem was established by the MBE, more specifically by MBE‐induced changes in global climate, which has led to more dynamic post‐MBE conditions. In a broader context, this implies that the MBE has played an important role in the establishment of the modern polar deep‐sea ecosystem and biodiversity in general. [ABSTRACT FROM AUTHOR]

The glacial‐interglacial cycle of elements and the linkage with biological production is very important. Nonetheless, records on incorporation of elements into diatom frustules are very poor in the Southern Ocean where diatom productivity is very high. As a result, there is a big gap in our understanding of elemental cycles in association with biological production and the controlling mechanisms. Here, we documented concentrations of major, trace, and rare earth elements of diatom frustules in two cores collected from the Southern Ocean since the Last Glacial Maximum to understand changes of incorporation of these elements into diatom frustules and to investigate mechanisms for changing incorporation. We found that there are three types of glacial‐interglacial variation patterns. Most elements showed increased (decreased) concentrations during the glacial period (interglacial) with decreased (increased) diatom production in the surface water following the variation pattern of magnetic susceptibility, whereas P, Ge, and Sb showed the opposite trend following the variation pattern of biogenic opal. Li, Ni, Ag, W, U, and I showed no clear glacial‐interglacial variation pattern. These different variation patterns imply that elemental incorporation into diatom frustules are also different according to elements. Our results revealed that biologically mediated removal of most elements from surface water to deep‐sea is comparable between glacial (low diatom production with high elements assimilation) and interglacial (high diatom production with low elements assimilation) periods in the Southern Ocean. However, more removal of P, Sb, and Ge in the surface water by diatoms occurs during interglacial periods in the Southern Ocean. Key Points: Concentrations of multi‐elements within diatom frustules were documented from the Southern Ocean since the Last Glacial Maximum (LGM)Most elements were assimilated/incorporated into diatoms synchronously: high (low) during glacial (interglacial) periodsP, Ge, and Sb showed low incorporation into diatom frustules during the LGM but increased during the Holocene [ABSTRACT FROM AUTHOR]

High‐relief glacial valleys shape the modern topography of the Southern Patagonian Andes, but their formation remains poorly understood. Two Miocene plutonic complexes in the Andean retroarc, the Fitz Roy (49°S) and Torres del Paine (51°S) massifs, were emplaced between 16.9–16.4 Ma and 12.6–12.4 Ma, respectively. Subduction of oceanic ridge segments initiated ca. 16 Ma at 54°S, leading to northward opening of a slab window with associated mantle upwelling. The onset of major glaciations caused drastic topographic changes since ca. 7 Ma. To constrain the respective contributions of tectonic‐mantle dynamics and fluvio‐glacial erosion to rock exhumation and landscape evolution, we perform inverse thermal modeling of a new data set of zircon and apatite (U‐Th)/He from the two massifs, complemented by apatite 4He/3He data for Torres del Paine. Our results show rapid rock exhumation recorded only in the Fitz Roy massif between 10 and 8 Ma, which we ascribe to local mantle upwelling forcing surface uplift and intensified erosion around 49°S. Both massifs record a pulse of rock exhumation between 7 and 4 Ma, which we interpret as enhanced erosion during the beginning of Patagonian glaciations. After a period of erosional and tectonic quiescence in the Pliocene, increased rock exhumation since 3–2 Ma is interpreted as the result of alpine glacial valley carving promoted by reinforced glacial‐interglacial cycles. This study highlights that glacial erosion was the main driver to rock exhumation in the Patagonian retroarc since 7 Ma, but that mantle upwelling might be a driving force to rock exhumation as well. Plain Language Summary: The isotopic system (U‐Th)/He in apatite and zircon record the ages in which a rock experiences relatively low temperatures (200–60°C) at shallow crustal depths (6–1 km). We present a new data set of low‐temperature thermochronometers for rocks of the Fitz Roy and Torres del Paine mountains in the Southern Patagonian Andes. Fast rock cooling can be forced by intensified surface erosion, and/or tectonic and mantle activity. An episode of fast cooling between 10 and 8 Ma was identified in the Fitz Roy mountains, and mantle upwelling forcing surface uplift, combined with high fluvial erosion may have caused fast rock exhumation. A regional episode of fast rock cooling between 7 and 4 Ma causing 1–3 km of exhumation in the Fitz Roy and Torres del Paine is coincident with the onset of Patagonian glaciations, which would have enhanced erosion and, thus, rock exhumation. An episode of fast rock cooling in the Quaternary is recorded in Torres del Paine rocks, interpreted as enhanced fluvio‐glacial erosion during the Plio‐Pleistocene climate transition toward faster glacial/interglacial cycles. Therefore, we were able to quantify separately the effects of tectonics and climate changes on rock exhumation, what is usually difficult due to simultaneously occurring processes. Key Points: Mantle upwelling in Southern Patagonia is the most likely mechanism forcing rock exhumation between 10 and 8 Ma in the Fitz Roy massifApatite (U‐Th)/He data reveal glacial erosion as the main driver to the exhumation of the Fitz Roy and Torres del Paine between 7 and 4 MaApatite 4He/3He data reveal intensified fluvio‐glacial erosion in Torres del Paine as a result of the Plio‐Pleistocene climate transition [ABSTRACT FROM AUTHOR]

A complete, fluvial stratigraphic record for the last glacial period of the Western Andes in Peru is not available due to preservation issues and spatial variability in sedimentation. Deposits are typically restricted to incomplete records of fluvial terraces or localised occurrences of alluvial fans and landslides. These landforms are thought to have formed under a regime of climate cyclicity controlling increases in precipitation. Because of the fragmented preservation of these deposits, as well as dating uncertainties, it remains unclear if orbital climate cycles, such as the precession cycle, or suborbital cycles, such as the wet Heinrich events, are driving Andean sedimentation. In this paper, we try to answer this question through a sedimentological–stratigraphical analysis of a much more complete sedimentary sequence than usually found in the region. We present the results of a grain size analysis of 5000 clasts and 13 new luminescence ages of a 52‐m‐long, stratigraphic section of the Lima fluvial fan in Peru. Bayesian age–depth modelling resulted in a robust chronostratigraphic framework and derived sedimentation rates. The stratigraphic record registered sedimentation from 121.7 ± 4 to 6.3−1.6+1.5 ka. Three major sedimentation periods occurred between 121.7 to 110−5+4, 87 ± 1 to 67−3+2, and 31−3+4 to 6.3−1.6+1.5 ka. These periods registered various unconformities and coarsening–fining upward sequences which chronologically correlate to suborbital pluvial periods, recognised from speleothems and lake records, that drove fluvial deposition. They also correlate with the timing of other recognised sedimentation events throughout the Western Andes. Marine regression resulted in fan progradation and not in incision. The Lima fan stratigraphy represents therefore the most complete, last glacial fluvial record for the Peruvian Western Andes to date and it highlights the potential of fluvial fans as recorders of suborbital climate variability. [ABSTRACT FROM AUTHOR]

Late Pleistocene glacial terminations are caused by rising atmospheric CO2 occurring in response to atmospheric and ocean circulation changes induced by increased discharge from Northern Hemisphere ice sheets. While climate records place glacial terminations coincident with decreasing orbital precession, it remains unclear why a specific precession minimum causes a termination. We compare the orbital and ice volume configuration at each precession minima over the last million years to demonstrate that eccentricity, through its control on precession amplitude, period and coherence with obliquity, along with ice sheet size, determine whether a given precession minimum will cause a termination. We also demonstrate how eccentricity controls obliquity maxima and precession minima coherence, varying the duration of glaciations. Glaciations lasting ∼100 thousand years are controlled by Earth's eccentricity cycle of the same period, while the shortest (20–40 ka) and longest (155 ka) occupy the maxima and minimums of the 400 thousand year eccentricity cycle. Plain Language Summary: The Milankovitch theory of the ice ages predicts that the growth and collapse of Pleistocene ice sheets is paced by the cycles in high latitude solar insolation that accompany variations in Earth's orbital motion. The orbital modes that dominate frequencies of incoming solar radiation are obliquity and precession, which operate at periodicities of approximately 40 and 20 thousand years, respectively. The dominant frequency at which ice sheets grow and collapse over the last million years is, however, approximately 100 thousand years, a closer match to eccentricity, an orbital period near absent from past solar radiation. Through a comparison between Earth's orbital configuration and an approximation of past global ice volume, we identify that the precession minima that trigger ice sheet collapse occur at distinct configuration of eccentricity and ice sheet size. In most cases terminations occur when precession minima align with obliquity maxima. We find that this coherence is influenced by the duration of precession cycles, which is in turn controlled by eccentricity. From these observations, we conclude that orbital eccentricity, through its control on both the amplitude and period of precession, paces the timing of glacial terminations and the size of Late Pleistocene ice sheets. Key Points: Late Pleistocene glacial terminations occur at distinct configurations of orbital precession, obliquity, eccentricity and ice volumeEccentricity controls the duration of precession cycles, and therefore the coherence of obliquity and precessionOrbital eccentricity, through its control on the amplitude and period of precession, paces Late Pleistocene glaciations [ABSTRACT FROM AUTHOR]

The last glacial inception (LGI) marks the transition from the interglacial warm climate to the glacial period with extensive Northern Hemisphere ice sheets and colder climate. This transition is initiated by decreasing boreal summer insolation but requires positive feedbacks to stimulate the appearance of perennial snow. We perform simulations of LGI with climate model AWI‐ESM‐2.1, forced by the astronomical and greenhouse gas forcing of 115,000 years before present. To compare with the preindustrial (PI) simulation, we use a consistent definition of the seasons during the LGI and the PI and evaluate model output on an angular astronomical calendar. Our study reveals a prominent role of the sea‐ice albedo feedback to amplify the delayed climate signal at polar latitudes. Through a radiative budget analysis, we examine that the ice‐albedo feedback exceeds the shortwave radiative forcing, contributing to the cooling and high latitude snow built‐up during LGI. Plain Language Summary: The onset of the last ice age marks the transition from the interglacial warm climate to the ice age with extensive Northern Hemisphere (NH) ice sheets and colder climate. This transition is initiated by decreasing boreal summer irradiance and reinforced by positive feedbacks. We perform climate simulations under the astronomical and greenhouse gas forcing, and use a consistent definition of seasons. Our study shows that a delayed ice‐albedo feedback plays an important role in generating a cold NH climate. Key Points: Climate simulations reveal year‐round cooling in the Northern Hemisphere high latitudes during the last glacial inceptionA refined angular calendar provides a tool to analyze the seasonal dynamicsWe identify the crucial role of the albedo feedback on the high‐latitude radiative budget [ABSTRACT FROM AUTHOR]

Piedmont glaciers (lobes), typically found in high latitudes and large mountainous regions, extend from ice sheets and ice caps to lower altitudes. However, they can also occur, although less commonly, on mid‐latitude mountains. When these fan‐like glaciers retreat, they leave behind hummocky moraines scattered in a chaotic pattern. In this study, we have mapped one of these mid‐latitude sites and established a Terrestrial cosmogenic nuclide (TCN) glacial chronology on Mount Davraz, namely Davraz hummocky moraine field (37°46′00″N, 30°43′15″E). Our findings indicate that the glaciers in this area started receding from the early local Last Glacial Maximum (LGM) period (21.8 ± 2.4 ka) to the early Late‐glacial period (17.7 ± 2.2 ka), and eventually disappearing. The deglaciation of the Mt. Davraz palaeoglacier matches nearby mountains, supported by southerly winds as significant for regional glaciation. Our discoveries reveal a robust connection between southerly winds and nearby glaciation, contributing to our understanding of how climate influences glaciers. Likewise, the glacial timelines of the neighbouring mountains align with the glacial history of Mt. Davraz. [ABSTRACT FROM AUTHOR]

Determining how gas hydrate distribution evolved along continental margins in the past is essential to understanding its evolution in the future. Moreover, hydrate decomposition has been linked to several catastrophic events, including some of the largest submarine landslides on Earth and the massive release of greenhouse gases into the ocean. Offshore Romania, the presence of a second bottom‐simulating reflector (BSR) provides an opportunity to gain valuable insights into hydrate dynamics since the Last Glacial Period (LGP). We conducted transient modeling of hydrate thermodynamic stability by merging in‐situ observations with indirect assessments of sea‐bottom temperature, thermal conductivity, salinity, sedimentation rate, and sea‐level variations. We reveal a strong correlation between the BSRs and the base of the Gas Hydrate Stability Zone (GHSZ) during both the present and LGP periods. The gradual evolution of the GHSZ over the past 34 ka presented here supports a conceptual model that excludes catastrophic environmental scenarios. Plain Language Summary: Methane hydrate is an ice‐like compound composed of a cage of water molecules enclosing a methane molecule. Hydrates can form in marine sediments along continental margins where water and methane are present under high pressure and low temperatures. As a result of climate change, hydrate melting has been linked to catastrophic events, including submarine landslides and the release of greenhouse gases into the ocean. Offshore Romania, the presence of a relic of the base of the hydrate layers formed in sediments during past glacial conditions, reveals the evolution of the hydrate stability zone since the last glacial period. The 2D modeling results have enabled us to define the area where hydrates alternately melt and reform in response to environmental changes such as rising temperatures and sea levels. Our results show that the evolution of gas‐hydrate accumulations generates multiple, slow chain reactions, preventing the system from disastrous destabilization, sequentially provoking catastrophic events. Key Points: A 2D modeling reveals the observed deeper secondary BSR is mostly consistent with a paleo‐BSR developed during the last glacial periodA paleo‐BSR can only be preserved in sediments if the period of stagnation of the base of hydrate layers is sufficient to trap enough gasAlthough rapid environmental changes, the hydrate‐free gas system reacts much more slowly preventing catastrophic submarine destabilization [ABSTRACT FROM AUTHOR]

The Ediacaran Period is of interest for the emergence of multicellular life, one or more glaciations, and the occurrence of the largest δ13C excursion in Earth history (the Shuram). The Ediacaran stratigraphic succession in the Flinders Ranges of South Australia is distinctive also for well‐exposed outcrop examples of palaeocanyons and salt diapirs. We present data placing a level of salt‐sheet breakout during deposition of the Wonoka Formation, within the time span of the Shuram, and at a datum indistinguishable from the canyon incision level. We hypothesize that canyon incision and salt breakout were triggered by subaerial erosion and non‐deposition associated with sea‐level drawdown in a temporarily isolated embayment. This mechanism provides support for the idea that the palaeocanyons were fluvially incised, and imposes a new constraint on the palaeoenvironmental setting of Australia at the time of the Shuram and the Ediacara fauna. [ABSTRACT FROM AUTHOR]

Pleistocene climatic oscillations exerted significant influences on the genetic structure and demography of rhesus macaque (Macaca mulatta) in eastern China. However, the evolutionary history of rhesus macaques in subtropical and temperate China remained unclear and/or controversial. Herein, we analyzed the autosomes, mitochondrial genomes, and Y‐chromosomes from 84 individuals of Chinese rhesus macaque. The results revealed that (1) all individuals were clustered into pan‐west and pan‐east genetic groups, which exhibited Shaanxi Province as the northernmost region of western dispersal route of rhesus macaques in China; (2) in subtropical and temperate China, rhesus macaques were divided into four lineages (TH, DB, HS, and QL), and their divergence times corresponded to the Penultimate Glaciation (300–130 kya) and Last Glaciation (70–10 kya), respectively; (3) the individuals from Mt. Taihangshan (TH) are closely related to individuals from Mt. Dabashan (DB) in the autosomal tree, rather than individuals from Mt. Huangshan (HS) as indicated by the mitogenome tree, which supports the hypothesis that the ancestral rhesus macaques radiated into Mt. Taihangshan from Mt. Huangshan via Mt. Dabashan; and (4) the demographic scenario of the four lineages showed the ancestral rhesus macaques bottleneck and expansion corresponding to the suitable habitat reduction and expansion, which confirmed they had experienced northward recolonization and southward retreat events from Mt. Huangshan area via Northern China Plain to Northernmost China along with Pleistocene glacial cycles. This study provides a new insight into understanding how Pleistocene glaciation has influenced faunal diversity in subtropical and temperate China, especially for those exhibiting differential patterns of sex dispersal. [ABSTRACT FROM AUTHOR]

Aim: The continental island system comprising Sakhalin, Hokkaido and the southern Kuril Islands (SHSK) in northeastern Asia serves as one of the southernmost habitats for many boreal and arctic organisms, with colonization via land bridges formed during glacial periods. To understand the impacts of past land‐bridge formation under Quaternary climate changes across SHSK, we investigated the demographic history of forest‐dwelling marten species. Location: Sakhalin, Hokkaido and the southern Kuril Islands in northeastern Asia. Taxon: Sable, Martes zibellina (Carnivora, Mustelidae). Methods: We employed multiplexed inter‐simple sequence repeat genotyping by sequencing (MIG‐seq) to obtain genome‐wide single nucleotide polymorphisms (SNPs). We tested possible scenarios of colonization and diversification for SHSK sables using several population genetics approaches including clustering analysis, population tree estimation and approximate Bayesian computation modelling. We also examined haplotype diversity for the mitochondrial ND2 gene. Results: The genetic diversity of the island populations and their affinity for continental populations were found to be higher in the order Sakhalin > Hokkaido > Iturup in both nuclear SNP and mitochondrial DNA analyses. Demographic analyses indicated that the sable migrated repeatedly from the continent, particularly to the neighbouring Sakhalin Island. However, only an earlier colonized lineage has persisted on marginal Iturup Island since the Middle Pleistocene. The stronger effects of repeated migrations and/or isolation influenced by the distance to the continent have shaped the contemporary genetic diversity and differentiation of sable populations in SHSK. Main Conclusions: Genome‐wide and comprehensive sampling approaches demonstrated that the forest‐dwelling sable had long‐term persistence with partial admixture of multiple lineages in SHSK, suggesting the existence of forest corridors and refugia on the islands during the last several glacial periods. The SHSK system of continental islands is valuable for understanding the impacts of Quaternary climate changes on the genetic diversity and evolutionary histories of boreal organisms. [ABSTRACT FROM AUTHOR]

Genetic assessment of species that have experienced dramatic population declines provides critical information that is instrumental for the design of conservation recovery programs. Here, we use different sources of molecular data (mtDNA and ddRAD‐seq) to evaluate the genetic status of wild and captive populations of marbled teal (Marmaronetta angustirostris), a duck species classified as critically endangered in Spain and near threatened at a global scale. First, we determined the evolutionary and demographic trajectories of the wild population from Spain and the currently much larger population from Iraq, which is also the documented source of European zoo stocks. Second, we evaluated the suitability of the different captive populations for ongoing restocking programs in Spain and assessed their potential impact on the genetic composition of wild populations. Populations from Spain and Iraq were assigned to distinct genetic clusters, albeit with an overall low level of genetic differentiation, in line with their recent divergence (<8000 years ago) and lack of phylogeographic structure in the species. Demogenomic inferences revealed that the two populations have experienced parallel demographic trajectories, with a marked bottleneck during the last glacial period followed by a sudden demographic expansion and stability since the onset of the Holocene. The wild population from Spain presented high levels of inbreeding, but we found no evidence of recent genetic bottlenecks compatible with the human‐driven decline of the species during the past century. The captive populations from the two Spanish centers involved in restocking programs showed genetic introgression from European zoos; however, we found limited evidence of introgression from the zoo genetic stock into the wild population from Spain, suggesting captive‐bred birds have limited breeding success in the wild. Our study illustrates how ex situ conservation programs should consider the genetic distinctiveness of populations when establishing breeding stocks and highlights the importance of genetically assessing captive populations prior to reinforcement actions. [ABSTRACT FROM AUTHOR]

Phylogeography bears an important part in ecology and evolution. However, current phylogeographic studies are largely constrained by limited numbers of individual samples. Using an environmental DNA (eDNA) assay for phylogeographic analyses, this study provides detailed information regarding the history of Siberian stone loach Barbatula toni, a primary freshwater fish across the whole range of Hokkaido, Japan. Based on an eDNA metabarcoding on 293 river water samples, we detected eDNA from B. toni in 189 rivers. A total of 51 samples, representing the entire island, were then selected from the B. toni eDNA‐positive sample set for the subsequent analyses. To elucidate the phylogeographic structure of B. toni, newly developed eDNA metabarcoding primers (Barba‐cytb‐F/R) were applied to these samples, specifically targeting their haplotypic variation in cytochrome b. After a bioinformatic processing to mitigate haplotypic false positives, a total of 50 eDNA haplotypes were identified. Two regionally restricted, genetically distinct lineages of the species were revealed as a result of phylogeographic analyses on the haplotypes and tissue‐derived DNA from B. toni. According to a molecular clock analysis, they have been genetically isolated for at least 1.5 million years, suggesting their ancient origin and colonisation of Hokkaido, presumably in the glacial periods. These results demonstrate how freshwater fishes can alter their distributions over evolutionary timescales and how eDNA assay can deepen our understanding of phylogeography. [ABSTRACT FROM AUTHOR]

We present the glacial history of the Makarov Basin (western Arctic Ocean) during the last ∼1.1 Myr, with sediment provenances using the newly refined chronostratigraphy of core ARA03B‐41GC02. According to the principal component analysis of the bulk mineral assemblages, felsic minerals were dominant, and their ratios (K‐feldspar/plagioclase and quartz/feldspars) indicated that sediment supply to the Makarov Basin was mainly from the Siberian margin and partly from northern North America, including the Canadian Arctic. However, their occurrence did not vary significantly between interglacials and glacials due to the mixed sources. In contrast, clinopyroxene and dolomite indicated specific sediment origins from the eastern Siberian margin and northern North America, respectively. The clinopyroxene content followed an eccentricity cycle (∼100‐Kyr) during the early to middle Pleistocene, suggesting that the eustatic sea level changes may have influenced its input from the eastern Siberian margin. The dolomite, transported primarily by icebergs from the Arctic sector of the Laurentide Ice Sheet (LIS) in northern North America, has also followed the same cycle since the early Pleistocene. Thus, the mineralogical signals highlight that sediment origins and transport processes in the Makarov Basin were related to ice sheet evolution at the eccentricity cycle. In addition, dolomite deposition in the Makarov Basin began by the early Pleistocene (∼790 ka), ∼150 ka earlier than in previous North Atlantic records (∼640 ka), indicating the earlier LIS calving in the Arctic sector than in the Atlantic sector. Plain Language Summary: We investigated past mineralogic changes in the Makarov Basin (western Arctic Ocean) over the last 1.1 million years using marine sediment core ARA03B‐41GC02. Bulk mineral analysis revealed that sediments in the Makarov Basin mainly originated from the Siberian margin, with a partial contribution from northern North America. However, sediments deposited during interglacial and glacial periods were mixed from different sources. Nevertheless, specific minerals such as clinopyroxene and dolomite allow us to distinguish different sediment sources between the eastern Siberian margin and northern North America. The clinopyroxene content fluctuated on a cycle of ∼100‐Kyr during the early to middle Pleistocene, suggesting an association with global sea level changes. The variation in dolomite content followed the same cycle, indicating that sediments containing dolomite were mainly transported by icebergs from the Laurentide Ice Sheet (LIS) in northern North America. These results linked sediment sources and transport processes to glacier evolution over cycles of ∼100‐Kyr. Interestingly, our study shows that dolomite deposition in the Makarov Basin began about 790,000 years ago, which is about 150,000 years earlier than previously reported (∼640 ka) in the North Atlantic, suggesting an earlier LIS calving into in the Arctic sector than in the North Atlantic sector. Key Points: Sediment provenances of clinopyroxene and dolomite are different (eastern Siberian margin and North America) in the Makarov BasinVariations in dolomite and clinopyroxene during the Pleistocene follow a ∼100 Kyr cycle of eccentricityDolomite in Makarov Basin ∼150 Kyr earlier than N. Atlantic implies Laurentide Ice Sheet calved into Arctic before extending to N. Atlantic [ABSTRACT FROM AUTHOR]

The Southern Ocean regulates atmospheric CO2 and Earth's climate as a critical region for air‐sea gas exchange, delicately poised between being a CO2 source and sink. Here, we estimate how long a water mass has remained isolated from the atmosphere and utilize 14C/12C ratios (Δ14C) to trace the pathway and escape route of carbon sequestered in the deep ocean through the mixed layer to the atmosphere. The position of our core at the northern margin of the Southern Indian Ocean, tracks latitudinal shifts of the Southern Ocean frontal zones across the deglaciation. Our results suggest an expanded glacial Antarctic region trapped CO2, whereas deglacial expansion of the subantarctic permitted ventilation of the trapped CO2, contributing to a rapid atmospheric CO2 rise. We identify frontal positions as a key factor balancing CO2 outgassing versus sequestration in a region currently responsible for nearly half of global ocean CO2 uptake. Plain Language Summary: The Southern Ocean is a key region for the inhalation and exhalation of carbon dioxide, responsible for absorbing nearly half of the total amount of atmospheric c taken up by the modern global ocean. Today, regions of communication between the deep ocean and atmosphere are bounded by oceanographic fronts. During cold glacial periods, when sea ice cover expanded in the Southern Ocean, these regions were shifted northward. Our data shows that this northward movement pinched together the fronts in the Southern Indian Ocean, restricting glacial ocean‐atmosphere gas exchange, allowing CO2 to accumulate in the deep ocean. We find that at the end of the glaciation, the fronts returned southward and expanded, allowing transfer of the stored CO2 into intermediate and surface waters before escaping to the atmosphere. This trapping and releasing mechanism driven by frontal shifts is important for understanding how changes in Southern Ocean dynamics can affect the ability of the oceans to take up the additional atmospheric CO2 produced from human activities. Key Points: Indian Ocean Antarctic Intermediate Water was a pathway for ventilation of a deglacial carbon reservoirLatitudinal shifts in the Southern Ocean fronts contributed to glacial carbon storage and deglacial ventilationIntermediate waters of the Southern Indian Ocean were more than 2,000 years older in the deglaciation than the glacial and Holocene [ABSTRACT FROM AUTHOR]

Glacial cycles lead to periodic population interbreeding and isolation in warm‐adapted species, which impact genetic structure and evolution. However, the effects of these processes on highly mobile and more cold‐tolerant species are not well understood. This study aims to shed light on the phylogeographic history of Aglais urticae, a butterfly species with considerable dispersal ability, and a wide Palearctic distribution reaching the Arctic. Through the analysis of genomic data, four main genetic lineages are identified: European, Sierra Nevada, Sicily/Calabria/Peloponnese, and Eastern. The results indicate that the Sardo‐Corsican endemic taxon ichnusa is a distinct species. The split between the relict lineages in southern Europe and the main European lineage is estimated to have happened 400–450 thousand years ago, with admixture observed during the Quaternary glacial cycles, and still ongoing, albeit to a much smaller extent. These results suggest that these lineages may be better treated as subspecific parapatric taxa. Ecological niche modelling supported the existence of both Mediterranean and extra‐Mediterranean refugia during the glacial periods, with the main one located on the Atlantic coast. Nevertheless, gene flow between populations was possible, indicating that both differentiation and admixture have acted continuously across glacial cycles in this cold‐tolerant butterfly, generally balancing each other but producing differentiated lineages in the southern peninsulas. We conclude that the population dynamics and the processes shaping the population genetic structure of cold‐adapted species during the Quaternary ice ages may be different than those classically accepted for warm‐adapted species. [ABSTRACT FROM AUTHOR]

This study presents the results of a 2D numerical basin and petroleum systems model of the Olga Basin in the NW Barents Sea offshore northern Norway, a frontier exploration area in which there are abundant seafloor oil and gas seepages. The effects of Pleistocene ice sheet advances on rock properties and subsurface fluid migration in this area, and on seafloor hydrocarbon seepage, are not well understood. The 2D numerical model takes account of recurrent ice advances and retreats, together with related erosional and temperature effects, and investigates the influence of these parameters on fluid migration. Model results show that Pleistocene glaciations reduced the temperature in the sedimentary succession in the Olga Basin by up to 20 °C, for example in the uppermost Cretaceous and Jurassic sediments which underlie the seafloor down to a depth of 0.5 to 1 km. The decrease in temperature was in general predominantly related to the intensity of glacial erosion, which was set in this study to a depth of 600 m based on previous studies. Hydrocarbon fluids expelled from potential thermogenic source rocks of Carboniferous to Triassic ages on the SW margin of the Olga Basin migrated to the seafloor through permeable carrier beds. However, fluid migration to the surface in the NE of the study area took place along fault conduits. In a closed fault model scenario, only 0.3 Mt of hydrocarbons are modelled to have migrated along the 0.5 km wide model section; in a second scenario with partially open faults, about 22 Mt of hydrocarbons, representing about 11% of the total hydrocarbons generated by potential thermogenic source rocks in the study area, were lost to the surface during the Pleistocene. The potential for microbial methane generation in the Olga Basin was limited both during the Pleistocene and at the present day due to the significant reduction in temperature during glacial episodes, and due to the intense glacial‐related erosion of the Mesozoic to Cenozoic stratigraphy. During glacial stages, the gas hydrate stability zone beneath the ice sheet is modelled to have extended to a depth of up to 900 m for a pure methane composition, and to a depth of up to 1100 m for a possible thermogenic‐sourced mixed gas composition of 90% methane, 7% propane and 3% ethane. Gas hydrates with this mixed composition are modelled to have been stable in the Olga Basin during the last three glacial advances and into the present. These modelling results provide an insight into the key factors controlling the migration and surface leakage of hydrocarbon fluids in the Olga Basin region, and into the effects of glaciations on rock properties in a glaciated basin. [ABSTRACT FROM AUTHOR]

Investigation of rarely studied gravel layers found in the loess in Shandong Province, eastern China, reveals the fabric characteristics of two gravel layers (G1, G2) and the sedimentary characteristics of loess at the typical and well‐preserved Heiyu section (HY), where, to determine the paleoclimatic changes during Marine Isotope Stage 3a. Optically stimulated luminescence dates of the HY formation range from 0.26 ± 0.02 ka to 39.00 ± 2.00 ka. In addition, the ages of G1 and G2 were estimated using the Bayesian model to be 39.60–40.50 and 29.00–29.50 ka. G1 and G2 are mainly composed of fine and medium gravel, both of which were subangular to subrounded limestone, with gravel directions to NE and E. The average flow velocity, average depth, and flood peak flow of G1 are 1.10 m/s, 0.49 m, and 37.04 m3/s, respectively, calculated using the flow energy method, whereas those of G2 are 0.98 m/s, 0.38 m, and 18.38 m3/s, respectively. Analysis of climate proxy indices show that the sedimentary environment of the gravel and loess in HY might be a regional response to global change. [ABSTRACT FROM AUTHOR]

To describe the composition of the penultimate glacial Brazilian Atlantic forest, we analyzed pollen, charcoal and diatoms deposited in the section from 871 to 1400 cm of core CO14 drilled in the Colônia basin in southeastern Brazil. The landscape was characterized by a cool grassland with three conifer genera: Araucaria, Podocarpus and Ephedra. Total arboreal pollen frequency did not change during the transition from glacial to interglacial conditions. Changes in Podocarpus frequency and concentration showed out‐of‐phase responses with austral summer insolation at an orbital scale while, at a millennial scale, both northern and southern hemisphere ice volume controlled the interplay between positions of the Inter‐Tropical Convergence Zone and South Tropical Front (STF), which in turn defined the latitudinal distribution of rainfall. The disappearance of Podocarpus and the decrease of Araucaria observed between ~167 and 160 ka were related to a dry interval which was not observed elsewhere. During Termination II a progressive decrease in conifer pollen taxa was in phase with a southward shift in the STF and increase in Atlantic sea surface temperatures. Our results show that southern hemisphere conifer distribution is strongly linked to austral summer insolation and winter precipitation and will be threatened by the southward expansion of the summer rainfall boundary. [ABSTRACT FROM AUTHOR]

Understanding the microscopic variability of impurities in glacier ice on a quantitative level has importance for assessing the preservation of paleoclimatic signals and enables the study of macroscopic deformational as well as dielectric ice properties. Two‐dimensional imaging via laser‐ablation‐inductively‐coupled‐plasma‐mass‐spectrometry (LA‐ICP‐MS) can provide key insight into the localization of impurities in the ice. So far, these findings are mostly qualitative and gaining quantitative insights remains challenging. Recent advances in LA‐ICP‐MS high‐resolution imaging now allow ice grains and grain boundaries to be resolved individually. These resolutions require new adequate quantification strategies and, consequently, accurate calibration with matrix‐matched standards. Here, we present three different quantification methods, which provide a high level of homogeneity at the scale of a few tens of microns and are dedicated to imaging applications of ice cores. One of the proposed methods has a second application, offering laboratory experiments to investigate the displacement of impurities by grain growth, with important future potential to study ice‐impurity interactions. Standards were analyzed to enable absolute quantification of impurities in selected ice core samples. Calibrated LA‐ICP‐MS maps indicate similar spatial distributions of impurities in all samples, while impurity levels vary distinctly: Higher concentrations were detected in glacial periods and Greenland, and lower levels in interglacial periods and samples from central Antarctica. These results are consistent with ranges from complementary meltwater analysis. Further comparison with cm‐scale melting techniques calls for a more sophisticated understanding of the ice chemistry across spatial scales, to which calibrated LA‐ICP‐MS maps now contribute quantitatively. Plain Language Summary: Compared to the large amount of information relating to paleoclimate signals reconstructed from cm‐scale impurity measurements on ice cores, knowledge about the spatial variability of impurities at the micro‐scale is extremely sparse—and becomes even more rare once quantitative datasets are concerned. However, there is an increasing demand for quantitative data for assessing the preservation of paleoclimatic signals and for the study of macroscopic deformational as well as dielectric ice properties in ice flow modeling and remote sensing. Two‐dimensional imaging via laser‐ablation‐inductively‐coupled‐plasma‐mass‐spectrometry (LA‐ICP‐MS) has shown great potential in this context, but so far, gaining reliable quantitative results for micro‐scale imaging has not been possible. Here, we present new quantification strategies that finally allow accurate calibration using ice standards. We carefully discuss the pros and cons of each method, apply the calibration to different samples from Greenland and Antarctica, and deliver the first calibrated LA‐ICP‐MS impurity maps at 40 μm resolution. Our results are consistent with bulk measurements performed on melted samples. The calibrated LA‐ICP‐MS maps will be essential for further comparison with bulk meltwater analysis, which may ultimately deliver an improved understanding of paleoclimate signals stored in deep ice. Key Points: This study presents new quantification strategies for two‐dimensional micro‐scale impurity imaging on ice cores with laser‐ablation‐inductively‐coupled‐plasma‐mass‐spectrometry (LA‐ICP‐MS)Calibrated LA‐ICP‐MS maps reveal similar spatial distributions of impurities in all ice core samples, while concentrations vary distinctlyWe developed a method to investigate the displacement of impurities by grain growth and to study ice‐impurity interactions in the laboratory [ABSTRACT FROM AUTHOR]

Eriophyoid mites are among the most species‐rich superfamilies (Eriophyoidea) in the Acari, consisting of over 5000 named species. Although they exhibit a geographically uneven worldwide distribution, their regional spatiotemporal evolutionary patterns remain largely unknown. Here, we compiled a data set including 3058 occurrence records assigned into 1203 species in China. We found that eriophyoid mite species richness is higher in the southeast and lower in the northwest of China, coinciding with the 500‐mm annual precipitation isoline. Using fragments of two mitochondrial genes (COI, 12S rRNA) and two nuclear genes (18S rRNA, 28S rRNA) of 304 eriophyoid mite species, we constructed a regional dated phylogenetic tree in China. Our spatiotemporal analysis revealed that mountains in eastern and southern China had high eriophyoid mite species richness and phylogenetic clustering, possessing both ancient and young mite lineages. Species distribution modelling (SDM) results showed that the predicted suitable area of eriophyoid mites slightly expanded from the last inter‐glacial period to the last glacial maximum period. In comparison with the current SDM, a significantly larger distribution range was observed in future scenarios. These findings suggest that mountains in eastern and southern China acted as not only cradles—recent rapid speciation, but also museums—centre of gradual accumulation and preservation and provide insights into monitoring and conserving eriophyoid mites. [ABSTRACT FROM AUTHOR]

Many north‐temperate tree species survived glacial periods in small, low‐density populations in refugia. These refugia are located in eastern and western North America, South Europe, East Asia, and western Asia. As a part of western Asia, Georgia harbors two main refugia: the Colchis in western Georgia and the eastern Great Caucasus, where many Cenozoic relict plants still exist. In this article, we report a new population of Pterocarya fraxinifolia (the Caucasian wingnut) which was discovered in the eastern Great Caucasus, near the village Lapankuri. The Lapankuri P. fraxinifolia stand is unique because the species grows not only in a narrow strip of riparian vegetation, but is also occurring in a broad band up to 100 m away from the river. Pterocarya fraxinifolia is dominant in the stand and is represented by large and old trees. Many other relict trees such as Diospyros lotus and Juglans regia are also present in the Lapankuri stand. Although some Cenozoic relict species are widely cultivated and naturalized in Central and Western Europe, natural stands of these plants provide the only evidence of their past growing conditions; therefore, conservation of this place is strongly advocated. [ABSTRACT FROM AUTHOR]

The Mediterranean Sea is recognized as a hotspot of marine biodiversity. Analysing its past biodiversity can help in understanding species' response to climate change. We built a species-level dataset of bivalve occurrences across the Zanclean-Calabrian interval, a time characterized by significant changes in climate, and by bivalve extinctions. The dataset includes more than 400 species distributed from the eastern to the western Mediterranean Sea. We measured changes in richness and turnover through time, for the entire dataset, and for different palaeoenvironments and combinations of tiering and feeding categories to test if specific environmental conditions and different lifestyles were correlated to species extinction or survival through time. We also compared niche breadth, geographical range size, and species abundance of extinct and extant species, to test which of these parameters potentially affected extinction risk. Our results confirm a loss of biodiversity between 3 Ma and the Early Pleistocene, although this loss was less intense and more gradual than previously estimated. We also found significant differences in niche breadth and geographical range size between extinct and extant species. Suspension feeders lost a higher proportion of species and suffered a higher reduction of geographical range compared to infaunal deposit feeders. Species loss was more protracted and higher on the shoreface than on the shelf, which is probably related to the reduction of shallow-water vegetated environments and to the disaggregation of heterozoan carbonate ramp habitats with cooling and sea-level drop at the onset of the northern hemisphere glaciation. [ABSTRACT FROM AUTHOR]

The late Asbian appears to mark the initial, well‐documented, onset of far‐field glacio‐eustatic changes in equatorial Mississippian strata. This work unravels the nature of cyclicity in upper Asbian shallow marine carbonates, using a combination of petrographic study, rock magnetic proxies and astrochronological testing on samples from the Trowbarrow section, NW England. Rock magnetic data express the content of two types of siliciclastic sources; a marine‐delivered magnetite‐dominated source, and an eolian‐delivered, hematite‐dominated source. The eolian‐sourced material generally peaked during regressive and low‐stand parts of the carbonate rhythms. Astrochronologic testing methods based around the average spectral misfit and TimeOpt methodology show the magnetite abundance proxies are principally carrying the astronomically forced signal. Two likely sedimentation rate models are derived from the five better magnetic proxies using evolutive methods. In addition, a set of three likely major hiatus levels are inferred in the sedimentation rate models, based on testing possible major hiatus scenarios with TimeOpt methods, using eccentricity modulation. From these, using the three best proxies, an average astrochronologic duration for the Trowbarrow section suggests a late Asbian duration of 1976 ± 86 kyr (1σ), and a basal late Asbian age of 334.48 ± 0.35 Ma (2σ). Coupled atmosphere‐ocean models for the late Paleozoic, suggest that lows in short eccentricity correspond to glacials, when inferred delivery of siliciclastic sediment to the carbonate ramp is generally at a maximum. The glacial and lower sea‐level intervals also coincide with maximum delivery of eolian siliciclastics, likely linked to increased aridity and less vegetation cover on adjacent and distal parts of Laurentia. Plain Language Summary: Around 332–333 million years ago changes in sea‐level driven by changes in polar ice volume were an important control on the sedimentation patterns through time in carbonates from low paleolatitudes. Understanding the pacing of these changes has implications for timescales and paleoceanographic processes. These cyclical changes in carbonate lithology are related to changes in magnetic properties within the late Asbian (late Visean) section at Trowbarrow in NW England. The magnetic changes principally express differences in the small content of silica‐based clastics, but also reflect changing Fe‐oxide mineralogy between times of hematite‐rich and magnetite‐rich clastic input. The changes are responding to differences in eolian delivery and marine dispersal of the clastics. Eolian delivery of clastics was at its peak near sea‐level lowstands, when nearby terrestrial systems were the most arid and supplying the most dust. Statistical assessments show that the magnetite abundance signal principally expresses changes in astronomical eccentricity. Primarily using the expected eccentricity pacing, two age models are constructed, which includes three levels of detectable hiatus in the section. Using these two age models and the three best magnetic proxies, the average late Asbian duration is 1976 ± 86 kyr, with the base of the late Asbian at 334.48 ± 0.35 Ma. Key Points: Rock magnetic properties show the included siliciclastics are from hematite‐rich eolian dust and marine‐dispersed sourcesThe magnetite mineral abundance proxies principally carry the primary eccentricity‐driven astronomical signalAn astrochronology for the late Asbian indicates its duration is 1976 ± 86 kyr [ABSTRACT FROM AUTHOR]

Biological systems occurring in ecologically heterogeneous and spatially discontinuous habitats provide an ideal opportunity to investigate the relative roles of neutral and selective factors in driving lineage diversification. The grey mangroves (Avicennia marina) of Arabia occur at the northern edge of the species' range and are subject to variable, often extreme, environmental conditions, as well as historic large fluctuations in habitat availability and connectivity resulting from Quaternary glacial cycles. Here, we analyse fully sequenced genomes sampled from 19 locations across the Red Sea, the Arabian Sea and the Persian/Arabian Gulf (PAG) to reconstruct the evolutionary history of the species in the region and to identify adaptive mechanisms of lineage diversification. Population structure and phylogenetic analyses revealed marked genetic structure correlating with geographic distance and highly supported clades among and within the seas surrounding the Arabian Peninsula. Demographic modelling showed times of divergence consistent with recent periods of geographic isolation and low marine connectivity during glaciations, suggesting the presence of (cryptic) glacial refugia in the Red Sea and the PAG. Significant migration was detected within the Red Sea and the PAG, and across the Strait of Hormuz to the Arabian Sea, suggesting gene flow upon secondary contact among populations. Genetic‐environment association analyses revealed high levels of adaptive divergence and detected signs of multi‐loci local adaptation driven by temperature extremes and hypersalinity. These results support a process of rapid diversification resulting from the combined effects of historical factors and ecological selection and reveal mangrove peripheral environments as relevant drivers of lineage diversity. [ABSTRACT FROM AUTHOR]

The reduction in the area and volume of glaciation in all mountain regions of the Earth has strongly accelerated for the last decades. In this work, we analysed the trends of the main climatic parameters which caused the glacier recession in the Kamchatka Peninsula. It was shown that the glaciers of the northern part of the Sredinny Range decreased by 125 km2 (35.6%) from 1950 to 2016–2017. The average rate of their reduction in the period from 2002 to 2016–2017 (1.45%/year) increased approximately 4.3 times compared to the period 1950–2002 (0.34%/year). The greatest reduction is observed in small glaciers with an area of less than 0.1 km2 and in glaciers with southeastern and southern expositions. On the Kronotsky Peninsula, the glacier area reduction for 1957–2019 was equal to 32.1 km2 (35.6%), and the rates were almost the same in the periods of 1957–2000 (0.61%/year) and 2000–2019 (0.67%/year). According to the data of weather stations and ERA5 reanalysis, it was shown that, in the ablation (summer) period the warming rate was minimal (0.3°C/10 years) and in the accumulation period a significant decrease in precipitation (5%–10%/10 years) was revealed in some areas. At the same time, a significant increase in the radiation balance was revealed in the warm season along with a tendency in downward shortwave radiation increase for the last two decades due to a decrease in cloud amount. These trends are in good agreement with the growth of the geopotential height over the North Pacific during the warm season in the 21st century, and with the growth of velocity divergence in the middle troposphere and the intensification of downward air movements. All this confirms an increase in anticyclone frequency in the warm season, which could be the cause of a radiation balance increase and, consequently, an increase in glacier ablation. [ABSTRACT FROM AUTHOR]

Aim: The Neotropics constitute the most biodiverse region of the world, yet its patterns of diversification and speciation differ among Neotropical areas and are not equally well understood. Particularly, avian evolutionary processes are understudied in the open habitats of temperate South America, where the role of glacial cycles is not clear. We analysed the evolutionary history of a Neotropical widespread bird species as a case study to evaluate its continental‐scale patterns and processes of diversification, with a focus on Patagonia. Location: Open habitats of the Neotropics. Taxon: Vanellus chilensis (Aves, Charadriiformes). Methods: We obtained reduced representation genomic and mitochondrial data from the four subspecies of V. chilensis to perform a phylogenetic/phylogeographical analysis and study the evolutionary history of the species. We complemented these analyses with the study of vocalizations, a reproductive signal in birds. Results: The initial diversification event within V. chilensis, approximately 600,000 years ago, split a Patagonian lineage from one containing individuals from the rest of the Neotropics. We found considerable gene flow between these two lineages and a contact zone in northern Patagonia, and showed that genomic admixture extends to northwestern Argentina. Shallower divergence was detected between the two non‐Patagonian subspecies, which are separated by the Amazon River. Vocalizations were significantly different between the two main lineages and were intermediate in their temporal and frequency characteristics in the contact zone. Main Conclusions: Patagonian populations of V. chilensis are clearly differentiated from those of the rest of the Neotropics, possibly as a consequence of Pleistocene glaciations. A secondary contact zone in northern Patagonia with extensive gene flow among lineages appears to be the consequence of post‐glacial, northward expansion of the Patagonian populations. Future analyses focused on the dynamics of the contact zone will allow us to establish whether the species continues to diverge or is homogenizing. [ABSTRACT FROM AUTHOR]

Upper Palaeozoic lacustrine basin deposits not only record local tectonism but are also an archive to evaluate global palaeoclimate changes linked to the Late Palaeozoic Gondwanan ice age. The Tournaisian Horton Group of Nova Scotia, south‐east Canada, accumulated in rift basins following the final accretion of peri‐Gondwanan terranes to the Appalachians. Sedimentology, mineralogy and geochemistry of the well‐exposed sandstones and shales at the classic Blue Beach section (ca 353.5 to 352 Ma) reveal the interplay of local tectonism and global climatic controls on lacustrine sedimentation. The lacustrine depositional environment gradually transitioned from deep water offshore at the base of the section to wave‐dominated and fluvial‐dominated nearshore at the top. Multiple small transgressive–regressive sedimentation cycles have an average 21 ka duration, likely related to Milankovitch cyclicity. Unusually abundant soft‐sediment deformation structures and landslides are the sedimentary responses to frequent earthquakes during the most active phase of rift subsidence. The overall succession shows changes from a shallowing‐up balanced‐filled to an overfilled lacustrine basin. The chemical weathering intensity index and the Th/K ratio show a longer‐term trend from dry and cool conditions low in the section to humid and warm conditions near the top, with rapid change in the transition period. The section records the peak of the global mid‐Tournaisian carbon isotope excursion and the corresponding cooling event (354 Ma to approximately 351 Ma). The sedimentary succession is a response to long‐term and short‐term climatic cycles influencing lake level and sediment supply during the time of maximum rift basin subsidence recorded by the soft‐sediment deformation structures. [ABSTRACT FROM AUTHOR]

Premise: Snow is an important environmental factor affecting plant distribution. Past changes in snowfall regimes may have controlled the demographies of snow‐dependent plants. However, our knowledge of changes in the distribution and demographies of such plants is limited because of the lack of fossil records. Methods: Population genetic and landscape genetic analyses were used to investigate the response of population dynamics of Arnica mallotopus (Asteraceae)—a plant confined to heavy‐snow areas of Japan—to changes in snowfall regimes from the Last Glacial Period to the Holocene. Results: The population genetic analysis suggested that the four geographic lineages diverged during the Last Glacial Period. The interaction between reduced snowfall and lower temperatures during this period likely triggered population isolation in separate refugia. Subpopulation differentiation in the northern group was lower than in the southern group. Our ecological niche model predicted that the current distribution was patchy in the southern region; that is, the populations were isolated by topologically flat and climatically unsuitable lowlands. The landscape genetic analysis suggested that areas with little snowfall acted as barriers to the Holocene expansion of species distribution and continued limiting gene flow between local populations. Conclusions: These findings indicate that postglacial population responses vary among regions and are controlled by environmental and geographic factors. Thus, changes in snowfall regime played a major role in shaping the distribution and genetic structure of the snow‐dependent plant. [ABSTRACT FROM AUTHOR]

Reconstructing the extent, style, timing and drivers of past mountain glaciation is crucial in both understanding past atmospheric circulation and predicting future climate change. Unlike in high‐elevation mountains situated in maritime and continental climates, less is known of past glaciation in mid‐altitude mountains, located in transitional climates, such as the Southern Carpathians of Romania. Despite these mountains harbouring a rich glacial geomorphology, this has never been systematically mapped according to well‐established morphological criteria, nor confidently related to former styles of glaciation. Therefore, filling this gap is important for not only accurately identifying glacial extents but also for establishing past glaciation styles and relating them to past ice dynamics and climate. Here, we devise the first glacial landsystem model for the Southern Carpathians, to enhance our understanding of the glaciation style and dynamics of past mountain glaciers in temperate‐continental climates. We present a geomorphological map, from which we infer the spatial and temporal evolution of glacial, periglacial and paraglacial landforms. We then assess the links between the mountain geomorphology and glaciation style and dynamics to construct a glacial landsystem model for debris‐charged plateau icefields and cirque glaciers in temperate‐continental mountain settings. [ABSTRACT FROM AUTHOR]

The analysis of LiDAR‐based digital elevation models revealed the existence of groups of longitudinal fractures in the ground in northern Poland at the limit of the ice sheet's extent during its last maximum. Our research on the closed elongated depressions (CEDs) of the Jedwabno test field (Szuć site, north‐east Poland) focuses on explaining their origins and their post‐glacial history. This region was covered by an ice sheet and glacitectonically active during the Vistulian, and at least some surface fractures are possible witnesses to this activity. Using geomorphological mapping, sedimentological and geophysical research, we assumed it was related that the origin of these features here is associated with groundwater migration at the end of the Vistulian glaciation or later when groundwater flow intensified due to a rapid climate warming that caused permafrost to melt. The thawing of permafrost caused to transition from continuous permafrost to discontinuous, which in turn created groundwater flow that was probably responsible for the development of the surface cracks (fractures). Radiocarbon, palaeobiological (pollen, Cladocera) and geochemical studies allowed for an estimation of the formation time of these unique surface cracks in the Older Dryas. Prevailing conditions were also reconstructed for the later dynamic changes of the end of the Late Vistulian glaciation and in the Late Holocene until the Subatlantic Period (Megalayan stage). The surface cracks with steep slopes, despite their small area, are extraordinary sedimentation traps that have, in a special way, retained an almost complete record of the environmental and climate changes of the Late Glacial. There are sedimentological gaps in the Holocene, especially after the Preboreal (old part of the Greenlandian Stage), caused by changes in water levels, aeolian processes and human activity. [ABSTRACT FROM AUTHOR]

The debate over isostatic uplift versus discharge as drivers of Quaternary river incision is explored here through geospatial analysis of a ~250‐m‐relief terrace sequence from the Río Pinturas (Argentine Patagonia). The geomorphic setting of the Cañadon Caracoles reach allows evaluation of discharge as a driver of terrace incision because advancing ice during Pleistocene glaciations blocked Pacific drainage and routed meltwater from an expanded ~104‐km2 catchment to the Atlantic through the dryland steppe of the study area. Twenty‐two terrace levels, some assigned to previously dated ice margins [Marine Isotope Stage (MIS) 32–36, MIS 16, MIS 8 and MIS 2], were identified. Average net incision since 800 ka (~0.34 m ka−1) exceeded regional uplift rates. The MIS 2 terraces, with ante quem and post quem age constraint on the timing of terrace formation, show that terrace incision was episodic and faster still during a transitional warming climate. Glacier recession and proglacial lake formation at ~18 ka led to rapid incision of ~11.7 m ka−1 over a few millennia. River capture and negligible flow from ~15.0 ka caused fan‐dammed lake formation on the valley floor and vertical stability during MIS 1. The Pinturas terraces demonstrate rapid incision can be driven by discharge and sediment dynamics. [ABSTRACT FROM AUTHOR]

In 2019 a sinkhole (doline) occurred in Late Devensian till above fissured limestone in northern England. Most sediment plugging the fissure was evacuated down into a karstic drainage system. The residual sedimentary fill comprises three main lithofacies, dated using optically stimulated luminescence to between 170.7 ± 40.0 and 56.1 ± 13.5 ka. The earliest date demonstrates fissures were present in the limestone pavement at the time of Marine Isotope Stage (MIS) 6, or shortly thereafter. The fissure filled with fine sand and silt due to surface runoff and aeolian processes probably at the MIS 6 to MIS 5e transition after Wolstonian glacial ice had retreated. The deposits then collapsed into the karst system. Further fine sand and silt deposition occurred during MIS 3; this deposit filled the central cavity surrounded by residual MIS 6/5e deposits. The sequence was capped by till as Late Devensian (MIS 2) ice transgressed the area. Solution fissures in the karst surfaces of northern England may pre‐date the Late Devensian glaciation. Moreover, fissures are repositories of pre‐Devensian sediment deposits which survived the Late Devensian glaciation and the Ipswichian interglacial. Such sites should provide information on the nature and timing of pre‐Devensian glacial–interglacial events and shed light on basal ice conditions and glaciokarst drainage behaviour. [ABSTRACT FROM AUTHOR]

The Ismenius Lacus region of Mars has a diverse geological history, and we present the first high‐resolution map of Deuteronilus Cavus (36.2°N; 14.0°E, ∼120 km diameter) in the fretted terrain south of the dichotomy boundary. Strong evidence suggests a volcanic origin of the regional plains, based on the ∼50 m thick volcanic bed underlying 180–300 m of sublimation residue associated with Amazonian plateau glaciation. Pervasive external volcanic flooding, internal erosional modification, and enlargement of a pre‐existing crater by up to 175%–200% resulted in the cavus' present shape. The phyllosilicates detected within Deuteronilus Cavus could be primary materials associated with the surficial aqueous activity, subsurface alteration products excavated by impacts, or a combination of both. We observe branching fluvial channels that are more recent than the traditional valley networks and may be related to fretted terrain resurfacing during the waning period of a high‐obliquity glaciation phase. This is consistent with our interpretation of the ∼600 m thick lobate and lineated deposits, which are remnants of receding glaciers. The glacial ice, protected by a 15–20 m insulating layer of debris cover, is of significant interest for future landing missions because of its potential to preserve biological and climatological signatures, to provide a critical test of Amazonian plateau glaciation, and to be used for in situ resource utilization. With our detailed geological mapping, we improved our understanding of the geological evolution and climatic conditions in the enigmatic fretted terrain near the dichotomy boundary. Plain Language Summary: The ∼120 km long Deuteronilus Cavus was initiated by an impact event. The resulting impact crater was modified by glacial erosional and fluvial processes, leading to the enlargement of 175%–200% of the pre‐existing crater. In addition, we find strong evidence for recent glaciation (<1 Ga) that left 180–300 m of sublimation residue on the plateau superimposed on a ∼50 m thick volcanic bed, suggesting a volcanic origin of the regional plains. During the waning period of a high‐glacial phase, the meltwater ponded on the surface of the cavus, altered surface rocks to produce phyllosilicates, formed channels (now observed as inverted sinuous ridges), and locally distributed branched fluvial channels that are more recent than the traditional valley networks. Glacial landforms still contain up to 600 m of remnant ice from the retreating glaciers at the end of the last glacial period. The relatively pure ice, protected by a 15–20 m insulating layer of debris cover, is critical for future landing missions because of its potential to preserve biological and climatological signatures and to be used for in situ resource utilization. Overall, this research enhances our understanding of the geological evolution and climatic history of Mars. Key Points: We have produced the first high‐resolution map of Deuteronilus Cavus in the fretted terrain south of the Martian dichotomy boundaryThe region records a complex erosional and depositional history, including fluvial and glacial processes in the Amazonian periodThis study provides a framework for exploration of high‐obliquity mid‐latitude plateau glaciation [ABSTRACT FROM AUTHOR]