ABSTRACTMultiple seas in East Asia have played distinct roles during the Quaternary climatic cycles, which have repeatedly isolated and reconnected temperate forest species, while it remains unclear whether their roles differ. In this study, we used Smilax sieboldii, a widely distributed species along the eastern coast of East Asia, to simultaneously evaluate the roles of multiple seas, including the East China Sea, the Yellow‐Bohai Sea, the Korea‐Tsushima Strait, and the Taiwan Strait, as geographic barriers and dispersal corridors during historical sea‐level fluctuations. We employed Bayesian clustering analysis and demographic simulations to elucidate the genetic structure and evolutionary history. The effects of spatial or environmental differences on population structure were examined through isolation by distance (IBD) and isolation by environment (IBE) tests. Further, genetic differentiation and gene flow were used as indicators to assess the roles of different seas as barriers or corridors. A pronounced phylogeographic structure was observed in S. sieboldii, with populations divided into three distinct gene pools separated by the East China Sea and the Korea‐Tsushima Strait, accompanied by significant genetic admixture at the lineage boundaries. The lineage divergence occurred during the early Quaternary, while secondary contact began in the most recent interglacial period. During population differentiation, the East China Sea and the Korea‐Tsushima Strait acted as effective geographic barriers, whereas the Taiwan Strait and the Yellow‐Bohai Sea functioned more as dispersal corridors and facilitated greater gene flow. Meanwhile, IBD rather than IBE explained the population structure of S. sieboldii. To conclude, the phylogeographic patterns of S. sieboldii resulted from population isolation and admixture due to sea‐level fluctuations since the Pleistocene, and the spatial scale of a sea largely determined its ecological role among the multi‐sea systems. These findings improved our understanding of how paleoclimate changes and geological transformations have shaped the speciation and diversification of temperate forest species in East Asia.

The Tibetan Plateau supports the largest alpine meadow ecosystem globally. It is considered extremely vulnerable to global warming. Knowledge of past vegetation dynamics under similarly warm climates could shed insights into where the tipping point for regime shifts may lie. We report a continuous multicentennial-resolved pollen record for the last 3.5 Myr from a lake sediment core retrieved from the Zoige Basin (~3,350–3,450 m above sea level) on the eastern Tibetan Plateau. It reveals a detailed picture of the vegetation dynamics across several timescales using the approaches of biomization, numerical analysis, statistical modelling and vegetation simulations. These lines of evidence show that vegetation underwent transformation from stable forest in the mid-late Pliocene Period (3.5–2.73 million years ago (Ma)) to codominance of forest and steppe in the early Quaternary Period (2.73–1.54 Ma) and to a meadow-dominated ecosystem after ~1.54 Ma, along with glacial–interglacial and millennial-scale grassland–forest shifts. These vegetational changes were largely controlled by temperature change. A global warming of ~2–3 °C is the most important threshold for the forest expansion and meadow resilience loss on the Tibetan Plateau. By analogy to the past, we suggest that, without major reductions in greenhouse gas emissions, the current Tibetan Plateau meadow is at risk of major transformation.

The theory of orbital forcing as formulated by Milankovitch involves the mediation by the advance (retreat) of ice sheets and the resulting variations in terrestrial albedo. This approach poses a major problem: that of the period of glacial cycles, which varies over time, as happened during the Mid-Pleistocene Transition (MPT). Here, we show that various hypotheses are called into question because of the finding of a second transition, the Early Quaternary Transition (EQT), resulting from the million-year period eccentricity parameter. We propose to complement the orbital forcing theory to explain both the MPT and the EQT by invoking the mediation of western boundary currents (WBCs) and the resulting variations in heat transfer from the low to the high latitudes. From observational and theoretical considerations, it appears that very long-period Rossby waves winding around subtropical gyres, the so-called “gyral” Rossby waves (GRWs), are resonantly forced in subharmonic modes from variations in solar irradiance resulting from the solar and orbital cycles. Two mutually reinforcing positive feedbacks of the climate response to orbital forcing have been evidenced: namely the change in the albedo resulting from the cyclic growth and retreat of ice sheets in accordance with the standard Milankovitch theory, and the modulation of the velocity of the WBCs of subtropical gyres. Due to the inherited resonance properties of GRWs, the response of the climate system to orbital forcing is sensitive to small changes in the forcing periods. For both the MPT and the EQT, the transition occurred when the forcing period merged with one of the natural periods of the climate system. The MPT occurred 1.25 Ma ago, when the dominant period shifted from 41 ka to 98 ka, with both periods corresponding to changes in the Earth’s obliquity and eccentricity. The EQT occurred 2.38 Ma ago, when the dominant period shifted from 408 ka to 786 ka, with both periods corresponding to changes in the Earth’s eccentricity. Through this paradigm shift, the objective of this self-consistent approach is essentially to spark new debates around a problem that has been pending since the discovery of glacial–interglacial cycles, where many hypotheses have been put forward without, however, fully answering all our questions.

The Cenozoic Nankang Basin in China records a complex series of tectonic, magmatic, metamorphic, and sedimentary events associated with the surrounding Shiwanshan, Liuwanshan, and Yunkaishan orogenic systems. The Nankang Basin is a critical location for studying the Cenozoic tectono–sedimentary evolution and strategic mineral resources of the southern Cathaysia Block. We used core samples from multiple boreholes and regional geological survey data to analyze the rock assemblages, sediment types, and sedimentary facies of the Nankang Basin. In addition, we analyzed the detrital zircon U–Pb geochronology, sandstone detrital compositions, heavy mineral assemblages, and major element geochemistry. The detrital zircon grains from Cenozoic sandstones in the Nankang Basin have age peaks at 2500–2000, 1100–900, 500–400, and 300–200 Ma, with most grains having ages of 500–400 or 300–200 Ma. The provenance analysis indicates that the 300–200 Ma zircon grains originated mainly from the Liuwanshan pluton; the 500–400 Ma zircon grains originated from the Ningtan pluton; and the 2500–2000 and 1100–900 Ma zircon grains originated from the Lower Silurian Liantan Formation and Middle Devonian Xindu Formation. This indicates that the provenance of Cenozoic sandstones in the Nankang Basin primarily originates from Paleozoic–Early Mesozoic igneous in the surrounding area, while the regional old sedimentary rocks possibly serve as intermediate sedimentary reservoirs. The detrital compositions of the sandstones and heavy mineral assemblages indicate a change in the tectonic setting during the deposition of the Nankang and Zhanjiang Formations, with a change in the source of the sediments due to the uplift of the Shizishan. During the deposition of the Nankang Formation, the sediment transport direction was to the NNW, whereas during the deposition of the Zhanjiang Formation, it was to the NNE. The uplift of the Shizishan most probably occurred during the late Neogene and early Quaternary, separating the Hepu and Nankang Basins.

ABSTRACT Sediments transported from source terrains to depositional sinks carry environmental signals, which may or may not be preserved in stratigraphy. Existing theory suggests that storage thresholds for environmental signals are set by the internal dynamics of sediment transport systems. We test this theory by exploring whether changes in relative sea level (RSL) of various scales produce detectable signals stored in field-scale strata. This field test builds on results from physical experiments where identifiable stratigraphic signals of RSL change were produced only from RSL cycles with magnitudes and/or periodicities greater than the spatial and temporal scales of the internal dynamics of deltas. Published long-term sedimentation rates and sea-level reconstructions suggest that the Mississippi River Delta (MRD) should be a good place to study sea-level-signal storage thresholds. We use publicly available seismic volumes from NAMSS-USGS, comparing strata of the late Miocene (LM) and early Quaternary (EQ), to study effects of paleo–sea-level change on the dimensions of channelized bodies in the MRD. Calculating dimensionless depth and time scales, we show that the likelihood that EQ channelized bodies store signals of relative sea-level change is higher than that in the LM channelized bodies. Observations lead to interpretations of paleovalleys preserved in the EQ strata, but not in the LM strata, which broadly supports predictions from signal-shredding theory. This study adds field-scale observations that quantify the intermingling of stratigraphic products of internal dynamics with products of RSL change over geologic timescales and underscores the need to appreciate stochasticity in surface processes when building hypotheses related to the stratigraphic record.

Ambrosia beetles and their fungal symbionts represent a widespread and diverse insect-fungus mutualism. This study investigates the genomic adaptations associated with the evolution of the ambrosia lifestyle across multiple fungal lineages. We performed comparative genomic analyses on 70 fungal genomes from four families (Irpicaceae, Ceratocystidaceae, Nectriaceae, and Ophiostomataceae), including 24 ambrosia and 34 non-ambrosia lineages. Our phylogenomic analyses reveal multiple independent colonization of insect vectors by the fungi, spanning from the mid-Cretaceous (114.6 Ma) to the early Quaternary (1.9 Ma). Contrary to expectations for obligate symbionts, ambrosia fungi showed no significant genome-wide modification in size, gene count, or secreted protein repertoire compared to their non-symbiotic relatives. Instead, we observed conservation of most assessed genomic features; where genome traits differ between free-living relatives and ambrosia fungi, the changes are lineage-specific, not convergent. Key findings include lineage-specific expansions in carbohydrate-active enzyme families (AA4 in Nectriaceae, CE4 in Ophiostomataceae, and GH3 in Ophiostomataceae and Ceratocystidaceae), suggesting potential enhancement or loss of lignin modification, hemicellulose deacetylation, and cellulose degradation in different ambrosia lineages. Repeat-Induced Point mutation analysis revealed family-specific patterns rather than lifestyle-associated differences. These results highlight the diverse genomic strategies employed by ambrosia fungi, demonstrating that symbiont evolution can proceed through refined, lineage-specific changes rather than genome-wide, or convergent alterations. Our genomic analyses do not reveal patterns typically associated with domestication in these ambrosia fungi, suggesting they may represent free-living fungi that co-opted wood boring beetles as vectors through subtle, lineage-specific adaptations.

Ancient dispersal events from the Korean Peninsula to the Japanese main islands of Honshu, Shikoku, and Kyushu (HSK), and from the Eurasian continent to Hokkaido via Sakhalin, have played a critical role in shaping the mammalian diversity of the Japanese archipelago. However, the timing and dynamics of these events remain incompletely understood across different taxa. In addition, the 100,000-year climatic cycles of glacial and interglacial periods during the Middle and Late Quaternary likely influenced intraspecific genetic diversity, although the mechanisms driving these changes remain unclear. In this study, we analyzed mitochondrial cytochrome b gene sequences from Japanese shrews (Sorex and Crocidura) and other small mammals from HSK and Hokkaido. Using an evolutionary rate of 0.029 substitutions/site/million years, we inferred that ancestral lineages of HSK species diverged during critical periods in the early Quaternary, such as around 2.4 and 1.7 million years ago (Ma), potentially in response to major climatic transitions. Notably, dispersal events of the masked shrew (Sorex caecutiens) and dark red-backed vole (Myodes rex) into Hokkaido around 1.7 Ma were also suggested. Regarding intraspecific mitochondrial DNA (mtDNA) lineages, species with broad distributions in HSK typically exhibit a north-south structure, characterized by two major lineages, as well as additional ancient lineages in surrounding offshore islands. Comparative analysis revealed that divergence among these lineages occurred at approximate intervals of 100,000 years. Our results indicate that the mtDNA genetic structure of HSK small mammals reflects geographic substructures shaped by climate-driven dispersal. Regions that facilitated rapid expansion during favorable climatic periods likely acted as centers of dispersal, from which haplotypes spread toward peripheral areas. As haplotypes radiated outward from these core regions, distinct mtDNA lineages became established across different geographic zones, giving rise to the spatial distribution patterns observed today.

A late Paleogene erosion event in the Sanshui Basin, southern margin of the South China Block and its tectonic significance

Buttonquails (family Turnicidae of the order Charadriiformes) are a morphologically specialized group of small, predominantly tropical birds of open landscapes, extremely poorly represented in the fossil record. The article describes a fragmentary humerus of a buttonquail from the Lower Pleistocene of the Taurida Cave in central Crimea. This is the first find of the family Turnicidae in Eurasia in the chronological interval from the Pliocene through the Middle Pleistocene. This find highlights the limited available information on the taxonomic composition of Early Quaternary Eurasian avifaunas, even at the family level, and also sheds light on the Late Cenozoic evolutionary history of Turnicidae.

The aim of this article is to investigate the Çiftlik Plain and the Central Anatolia Cappadocia Volcanic Province, the unexplored Quaternary fills, and their climate records. This studies has gained importance as it completes a deficiency in the region.A confluence is where a tributary joins a larger river which depicts an important area of deposition which is an essential geomorphological node that controls the downstream routing of flow and (P2), located between latitudes N38°11' and longitudes E34°27', at an altitude of 1532m above sea level in the Çiftlik Basin. In this Confluence in Çiftlik (M-1 to M-10) (A-J), consisting of paleosols and terrestrial sediments (P2), in which a profile from a collection of 41 specimens was initially examined. This article evaluates therefore the depositional sequences of sediments brought in by the Melendiz stream that flourished during the Early Quaternary. The Quaternary fills are made up of terrestrial sediments and paleosols and consisted of fined, medium and coarse grains ranging from peat, silt. clay, sands, pebbles of various different sizes. Some of these grains came from the immediate surroundings seen from their coarse and angular shapes while the fined grains must have travelled for a long distance having been worked and reworked by wind and running water. To determine the quality and quantity of the collected samples, the samples were prepared for measurement by passing the necessary processes according to the type of sedimentological, mineralogical, soil types and XRD. By analyzing the data obtained from these measurements, the mineral types, distributions, chemical components, and trace elements contained in partially lithified or unconsolidated sediments of the region were determined. The relationship of these data with paleoclimate has been revealed and compared with the Central Anatolian climate records. The Pliocene lake regressed toward the west on account of the progressions in the structural system and geomorphological cycles during the late Pliocene (~ 3 Ma ago) and the underlying Melendiz Waterway created on the lake base. During the Quaternary the Melendiz Stream created heavily influenced by both the neotectonic system and the environment. The sediments are very poorly sorted in some levels of unconsolidated or partially lithified sediments and paleosol, and poorly sorted in some levels. On the other hand, quartz, feldspar, amphibole, and rock fragments such as metamorphic, volcanic and igneous are commonly observed in paleosol, silty and sandy levels. In XRD measurements, paleosol, silty and sandy levels contain common feldspar, quartz, amphibole, Opal CT and Opal A minerals. The amounts of smectite, chlorite, illite as clay minerals at these levels vary at various levels of the profiles. The results of these calculations help us to explain the sediment-paleosol formation processes. They are of the Quaternary and primarily Holocene.

The geological structure of Neopleistocene deposits was specified along a 19-kilometer section of the right bank of the lower Pechora between the villages of Garevo and Sergeevo-Shchelya. The presence of three glacial and two interglacial horizons was revealed in coastal outcrops, and the material composition of the composing sediments was studied. The formation of the most ancient moraine horizon was associated with Fennoscandinavia and occurred in the early Quaternary Pomusov (Oka) time. The Pomusov moraine was overlain by Chirva (Likhvin) interglacial alluvial and lacustrine sediments. In the Middle Neopleistocene glacial complex, two morainic strata of different ages were distinguished: Pechora (Dnieper) and Vychegda (Moscovian), separated by a pack of predominantly coastal-marine littoral sediments, and alluvial and lacustrine sediments, the age of which was determined as Rodionov (Shklov) by the palynological method. Differences in the lithological composition of moraines confirmed a double glaciation of the European North-East of Russia in the Middle Neopleistocene.

The first results of U–Th–Pb isotope dating of detrital zircons (dZr, N = 130, n = 91) from the Middle Danian sandstones (63.9–65.3 Ma) of the Cretaceous–Eocene Novorossiysk–Anapa flysch, widely developed in the Sochi synclinorium (Southern slope of the Western Caucasus) are presented. The maximum dZr age is 2973 ± 12 Ma, the minimum dZr age is 318 ± 3 Ma; weighted average age of the 4 youngest dZr ~ 322 ± 7 Ma. There are no signs of the destruction products of the Jurassic magmatites involved in the structure of the Greater Caucasus and the Crimean Mountains into the sedimentary basin, in which the Novorossiysk-Anapa flysch was formed. A high degree of similarity between the provenance signals of the Danian sandstones from the Novorossiysk-Anapa flysch, some Paleogene-Neogene and Early Quaternary (Early Pleistocene) sandstones of the Western Caucasus and Western Cis-Caucasia, red-colored Upper Permian and Lower Triassic sandstones of the Moscow syneclise, as well as Late Quaternary alluvium of the lower reaches of the draining vast expanses of the Russian plate Don and Volga rivers has been revealed. On this basis, it was concluded that in the Middle Danian there were no eroded mountain structures of the Greater Caucasus and Crimea, and the main volume of detrital material composing the Novorossiysk-Anapa flysch was formed due to the recycling of Permian-Triassic and younger strata of the Russian Plate.

In 1929, Matuyama published his paper on the magnetization of mostly Quaternary volcanic rocks. In this paper, he described the results of paleomagnetic measurements of volcanic rocks from Japan and nearby areas and concluded that the latest transition of the magnetic field from reversed to normal state occurred in the early Quaternary. In the 1960s, two groups of scientists from the USA and Australia quite vigorously conducted studies of both magnetization and age of volcanic rocks. By about 1966, they completed the reversal timescale for the last 4 million years, which was to become the basis for many earth science studies. For easy reference, they suggested to call the most recent normal or reversed periods as Brunhes, Matuyama, Gauss, and Gilbert polarity epochs, with the names taken from the scientists who made very important contributions to paleomagnetism. Chron is now the official term for the epoch, and each chron is specified by a combination of a number and a character showing the polarity. However, the names of polarity epochs were already so popular that they are still quite frequently used in scientific papers. The Matuyama epoch is between 0.773 and 2.595 million years before present. Moreover, its lower limit is now used to define the start of the Quaternary.

Geomorphological and geo/thermo-chronological responses of Indian plate’s deformation during neogene- quaternary time along the Eastern Himalayan Syntaxis: Formation of Manabhum anticline

Buttonquails (family Turnicidae of the order Charadriiformes) are a morphologically specialized group of small, predominantly tropical birds of open landscapes, which is extremely poorly represented in the fossil record. The article describes a fragmentary humerus of a buttonquail from the Lower Pleistocene of the Taurida Cave in central Crimea. This is the first find of the family Turnicidae in Eurasia in a chronological interval from the Pliocene through the Middle Pleistocene. The find highlights the limited nature of available information on the taxonomic composition of Early Quaternary Eurasian avifaunas, even at the family level, and sheds light on the Late Cenozoic evolutionary history of Turnicidae.

Cryptic diversity and rampant hybridization in annual gentians on the Qinghai-Tibet Plateau revealed by population genomic analysis

Cosmogenic nuclide chronological constraints on the late Cenozoic strata of the Linxia Basin, northeast Tibetan Plateau

Buried river valleys from the Neogene–Quaternary time are widespread throughout the Middle Volga region of the Russian Plain. They have been studied for a long period, since the 1940s, with the last major generalizations dating back to the 1980s. This paper presents new results based on GIS mapping using materials from the state geological study of the region in 1960–1970, 1984–1996 and 2000–2002. On the whole, the pattern of the buried valley network is close to the modern valley network of the region. During the Quaternary, the right-sided displacement of the valley incisions prevailed. The incisions of modern river valleys are located above the Neogene (pre-Akchagyl) incisions almost throughout the entire territory. The vertical displacement amplitude ranges from 30 to 200 m. The morphometric characteristics of the paleovalleys (the depth and width of the incisions, as well as the gradients of the bottoms of the paleovalleys) exceeded modern ones. The maximum values were typical for the middle Paleo-Volga valley: the width of the valley reached 10 km, the incision depth was−201.4 m below sea level and the bottom gradient was 0.9–5.0 m/km. The most important factor that influenced the position of paleovalleys and their morphological appearance was fluctuations in the level of the Caspian paleowaterbody. According to this study, the development of paleovalleys began in the Miocene and ended in the Early Quaternary. The alluvial–lacustrine type of sedimentation was predominant. The results of this work contribute to the study of the paleogeography of the Cenozoic of the southeast of the Russian Plain.

This study aims to compare the clay mineralogy and whole-soil major chemistry of elements in late Miocene soil sediments and early Quaternary red paleosols in the Penghu Islands, (Pescadores), Taiwan, and Zhangpu Volcanic Park, Fujian. There were the late Miocene Chu Wan (CWI and CWII), Shiao Men Yu (SMY) and two intergrade red soils, Chu Wan (CW(irs)) and Shiao Men Yu (SMY(irs)), with three distinctive zones of different dominating kaolins in the profiles of the Penghu Islands. A Tong Wei (TW) paleosol of early Quaternary basaltic eruptions in the Penghu Islands was collected. The Anzei (AZ), Si Yu (HY) and Chianmei (CM) paleosols were sampled from the Penghu Islands and Yulinshi (YLS) paleosols near the Zhangpu Volcanic Park for this study. The CW and SMY paleosols erupted in the late Miocene, and the other paleosols erupted on the Penghu Islands. These paleosols were fractionated into clay fractions and subjected to soil physical and chemical analyses. Kaolin minerals were dominant in the CW(irs) and SMY(irs) paleosols. The top layer (layer one) in the CW(irs) was 7 Å-halloysite, and order/disordered kaolinites were present in layers two and three. The CW(irs) and SMY(irs) hexagonal-like, platy kaolinites (0.1–0.2 µm in diameter), spheroidal and hollow 7 Å-halloysite (layer 1) was determined with transmission electron microscopic (TEM) investigations. The early Quaternary red soil of TW consisted of kaolinite, illite, vermiculite and smectite clay assemblages. Late Miocene paleosols were classified as fine, kaolinite, hyperthermic and Typic Rhodic Paleudults, and the early Quaternary red paleosols were classified as fine, mixed, hyperthermic and Typic Rodistalf, respectively. Late Miocene paleosols contained more clays, lower SiO2/Al2O3 and higher chemical index of weathering (CIW) than early Quaternary paleosols. The kaolin, illite, smectite and vermiculite mineralogy, physical and chemical properties of paleosols and landscapes in the Zhangpu YLS, Fujian, were similar to those of late Miocene sediments and early Quaternary red paleosols in the Penghu Islands.

Subfossil insects (mostly beetles) are common in the Late Cenozoic terrestrial loose deposits of the Arctic. The best-studied areas are those regions that remained ice-free during the Pleistocene — in Alaska and Yukon, northeast Siberia, and west Chukotka. Tertiary subfossil insects have been found in Alaska, Yukon, Canadian Northwest Territories, and Greenland. The northernmost sites (above 75°N) are Ellesmere and Meighen Islands in Canada, Kap Kobenhavn in Greenland, and Faddeyevsky and Navaya Sibir’ Islands in Siberia. Collections from North America and Russia are housed in research institutions such as The Geological Survey of Canada (GSC) in Ottawa, University of Alberta (UofA) in Edmonton, Paleontological Institute (PIN) in Moscow, and Institute of Plant and Animal Ecology in Yekaterinburg; collections from Greenland are housed in the Zoological Museum, University of Copenhagen. The collections are mainly used for research purposes, including reconstruction of past climate and environment, stratigraphy, origin of local faunas, and ecosystems of the past. A few extinct species have been described from the late Neogene and early Quaternary.