Middle Pleistocene Research Articles

Late Middle Pleistocene (MIS 10–6) glacial–interglacial records from loess–palaeosol and fluvial sequences from northern France: a cyclostratigraphic approach

This contribution summarizes the most informative loess–palaeosol sequences (LPS) and fluvial terrace records from the late Middle Pleistocene (LMP) of northern France demonstrating the reliability of the cyclostratigraphic approach for the interpretation of pedosedimentary sequences controlled by major glacial–interglacial climatic cycles. In this area, continental mollusc assemblages from interglacial fluvial silts and calcareous tufas are particularly rich and diverse and marker species define the malacological signatures of each interglacial optimum for Marine Isotope Stages (MIS) 11, 9 and 5e. This approach shows that the forest was less developed during MIS 7, suggesting that climatic conditions were either drier and/or cooler than during other Pleistocene interglacials. In the Somme basin, the terrace system shows that two alluvial formations were deposited between early MIS 8 and late MIS 7. In some LPS, the occurrence of two pedosedimentary sub‐cycles (IIa and IIb), separated by a relatively long (~12 ka) and cold period, corresponding to an ‘aborted glacial’ (MIS 7d), underlines the complex pattern of this unusual ‘interglacial’. Overall, during the LMP, each soil complex corresponding to interglacial and early‐glacial periods from MIS 11 to MIS 5 is broadly made up of the same soil facies but exhibits a specific succession pattern or signature. Throughout the area, LPS show a huge change in both the deposition rates and the geographical extent of typical calcareous loess at the beginning of MIS 6. This so‐called ‘Loess Revolution’ probably reflects a change in the palaeogeography of the southern North Sea and eastern Channel source areas at times marked by the coalescence of the British and Scandinavian ice sheets. MIS 6 is also characterized by the oldest evidence of permafrost development in the area. In addition, this work allows the age of the Lower/Middle Palaeolithic boundary to be confirmed, with the oldest occurrence of Levallois technology being around 300 ka.

Palaeoenvironmental Conditions of the Upper Middle Pleistocene Warm Intervals in the Upper Volga Region, Northwestern Russia, Based on Palynological, Paleocarpological and Quantitative Geochronological Data

The climatostratigraphic scale of the Upper Middle Pleistocene in the northwest of the East European Plain contains a number of controversial issues, one of which is the position of the Likhvin (Holstein) Interglacial and lesser warm (interstadial) climatic events. To approach this problem, we have studied two sections of Quaternary deposits, Bolshaya Kosha (a well-known and long-studied natural exposure) and Nazarovo (a new, previously unknown section studied in a borehole), in which warm intervals of the Middle Pleistocene are recognized. In both sections, we performed lithological and paleobiological (carpological, spore-pollen) analyses and luminescence dating. In the Bolshaya Kosha section, seeds of the extinct species Caulinia goretskyi were revealed, which allowed us to attribute the obtained IRSL (ca 250–260 ka) dates to the post-Likhvin Bolshaya Kosha interstadial. The sum of data let us propose that both our IRSL and recently published 230Th/U dates (ca 240–290 ka) underestimate the age by 10–15%, and the post-Likhvin Kosha interstadial deposits were formed in the late MIS 9. In the Nazarovo section, palynological study showed the conditions of a relatively warm interstadial, with a change in the composition of vegetation from northern to middle taiga forests. According to IRSL dating, the section was formed in the MIS 10 late glacial between 330–370 ka. The two studied interstadials bracket the Likhvin (Holstein) Interglacial and sedimentary units in the Bolshaya Kosha section are proposed to have formed in MIS 9e.

High-resolution seismic record of the Quaternary palaeoenvironments along a Dalmatian-type coast (Lošinj Channel, Adriatic Sea)

Coastal systems have changed considerably in response to Quaternary glacial–interglacial variability. Here, we offer the first detailed assessment of geomorphic features and late Quaternary sedimentation dynamics in the Lošinj Channel in the Adriatic Sea. The present study attempts to resolve the complex evolution of the environments by applying high-resolution seismic records that build upon sediment core data. Within this coastal karst basin, a significant amount of sediment accumulated during the Quaternary. Notably, the existence of several prominent erosional and depositional environments was revealed. We distinguished recurrent episodes of fluvio-lacustrine and marine sedimentation that probably occurred since Marine Isotope Stage (MIS) 6. The preserved record consists of erosional features and subparallel and oblique reflectors attributed to glacial periods (Seismic Units SU-II, SU-IV, and SU-V). Interglacial units are acoustically semitransparent and generally reflection-free (Seismic Units SU-I and SU-III). The mutual influence of sea level and climate change, sill depth, and karst hydrology enabled environmental changes in the Lošinj Channel. The area proves to be important for Quaternary studies because it contains a long sediment succession spanning at least the middle and late Pleistocene and Holocene. Our study has implications for the assessment of the long-term palaeoenvironmental evolution of similar coastal settings and reconstruction of the regional palaeogeography which is in turn crucial for understanding prehistoric human occupation and/or dispersal. This is one of the few well-preserved records in the Adriatic Sea that provides insight into submerged landscapes and sea levels since the penultimate glacial.

Quaternary tectonic and climatic forcing on the spatio-temporal evolution of the Meuse fluvial terrace staircase

The Quaternary is characterized by pronounced alterations between cold and warm climatic states, with the Mid-Pleistocene Transition marking a strong increase in the intensity of cold-climate conditions. River systems are sensitive to environmental perturbation (e.g., climate, tectonics, base level) and are expected to respond to such profound changes. This study uses a combination of terrace mapping and analysis of a dense borehole database to investigate the Meuse terrace staircase (and its deposits), and gain insight on how it reflects climatic and tectonic perturbations during the Quaternary. The lower reaches of the Meuse river, which has both its main water and sediment source in the Ardennes displays a well-developed terrace staircase that was sculpted mainly throughout the Quaternary. The staircase is located near the cities of Maastricht (southern Netherlands) and Liège (northwestern Belgium). About 30 terrace levels reflect signals of environmental perturbations in the lithological composition, gradients, thicknesses, and spatial distribution. The terraces are organized in groups, based on their morphological position, from old to young; these are the East Meuse terrace group and West Meuse High-, Middle- and Low terrace groups. Our findings show a consistent increase in the gravel content from older to younger terraces. The sandier composition of the deposits of the oldest terraces (Early Pleistocene) is closely related to the supply of the Miocene-Pliocene weathered material from the Ardennes. Younger terraces (Middle and Late Pleistocene) are much richer in gravel, evidencing sediment input from fresh or partially weathered bedrock. These changes point to a downstream migration of the gravel front throughout the Quaternary. The mean thickness of the terrace groups shows a slight increase, even though the same trend is not clear when each terrace is analyzed on an individual basis. The anomalous thickness of the Caberg 1 terrace suggests increased sediment input during the cold climatic conditions of the Elsterian (MIS 12), the first Quaternary glacial during which an ice sheet extended into the northern Netherlands. Reconstruction of terrace gradients reveals that older East Meuse terraces show a (reversed) gradient opposite to reconstructed palaeo flow directions, which is attributed to a combination of low gradients during terrace formation and footwall back-tilting of the Feldbiss Fault Zone. In our analysis we do not see clear evidence for the imprint of the Mid-Pleistocene Transition, which suggests that due to its gradual nature, its signal is either buffered or assimilated by the overall climatic signal of the Quaternary. This study offers a first complete temporal analysis of the Meuse terrace staircase, providing an important basis for better understanding the effects of Quaternary climatic change and tectonics, and their resulting effects in other river systems worldwide.

Qaleh Kurd Cave (Qazvin, Iran): Oldest Evidence of Middle Pleistocene Hominin Occupations and a Human Deciduous Tooth in the Iranian Central Plateau

Qaleh Kurd Cave (Qazvin, Iran): Oldest Evidence of Middle Pleistocene Hominin Occupations and a Human Deciduous Tooth in the Iranian Central Plateau

Virtual reconstruction and geometric morphometric analysis of the Kocabaş hominin fossil from Turkey: Implications for taxonomy and evolutionary significance

The Kocabaş specimen comes from a travertine quarry near the homonymous village in the Denizli basin (Turkey). The specimen comprises three main fragments: portions of the right and left parietal and left and right parts of the frontal bone. The fossil was assumed to belong to the Homo erectus s.l. hypodigm by some authors, whereas others see similarities with Middle Pleistocene fossils (Broken Hill 1/Kabwe, Bodo, or Ceprano). Here, we present the first attempt to make a complete reconstruction of the missing medial portion of the frontal bone and a comprehensive geometric morphometric analysis of this bone. We restored the calotte by aligning and mirroring the three preserved fragments. Afterward, we restored the missing portion by applying the thin-plate spline interpolation algorithm of target fossils onto the reconstructed Kocabaş specimen. For the geometric morphometric analyses, we collected 80 landmarks on the frontal bone (11 osteometric points, 14 bilateral curve semilandmarks, and 41 surface semilandmarks). The comparative sample includes 21 fossils from different chronological periods and geographical areas and 30 adult modern humans from different populations. Shape analyses highlighted the presence in Kocabaş of features usually related to Middle Pleistocene Homo, such as a developed supraorbital torus associated with a relatively short frontal squama and reduced post-toral sulcus. Cluster analysis and linear discriminant analysis classification procedure suggest Kocabaş being part of the same taxonomic unit of Eurasian and African Middle Pleistocene Homo. In light of our results, we consider that attributing the Kocabaş hominin to H. erectus s.l. may be unwarranted. Results of our analyses are compatible with different evolutionary scenarios, but a more precise chronological framework is needed for a thorough discussion of the evolutionary significance of this specimen. Future work should clarify its geological age, given uncertainties regarding its stratigraphic provenance.

The use of bones as tools in Late Lower Paleolithic of Central Italy

The Latium area in Italy has yielded rich evidence of Lower Paleolithic sites with both faunal remains, artefacts, and human fossil remains, such as the Ceprano human skull. Many are the sites where lithic industry has been found in association with bone industry. Medium and large animals were a key resource because they provided an enormous amount of meat and fat. However, they were extensively exploited for their bones, rich in marrow, and as raw material for tool production. Bone tools are so far few documented for early period of time and especially for the Middle Pleistocene in Western Europe. We report here evidence of bone tools and their efficiency of use for hominin groups living in the Frosinone-Ceprano basin during the MIS 11/10, a key period which records behavioral innovations and onset of the Neanderthal behaviors. In three sites, Isoletta, Colle Avarone and Selvotta, several bone tools and bone flakes have been discovered (MIS 11/10). They were associated to stone artefacts part of the hominins tool-kit. Technological and use-wear analyses conducted on these bone industries, dated between 410 and 430 ka, yield relevant results to understand the effectiveness of the bones tools found associated with lithic series, including handaxes.

The Undescribed Juvenile Maxilla from Contrebandiers Cave, Morocco—A Study on Middle Stone Age Facial Growth

In 2009, renewed excavations at the Middle Stone Age (MSA) site of Contrebandiers Cave, Morocco, yielded a skull and partial skeleton of a child dated to Marine Isotope Stage 5. While much of the cranium was found shattered, the midface remained largely intact. In this study, we virtually reconstructed the maxilla and quantified its shape using three-dimensional geometric morphometric methods and compared it to an extensive sample of non-adult and adult Eurasian Neanderthals and Homo sapiens spanning the Middle Pleistocene to Holocene. We used developmental simulations to predict the adult shape of the Contrebandiers maxilla by simulating development along three ontogenetic trajectories: Neanderthal, African, and Levantine early H. sapiens and Holocene H. sapiens. Our results confirm the H. sapiens-like morphology of the Contrebandiers fossil. Both shape and size align it with other North African MSA fossils and Late Pleistocene humans from Qafzeh, Israel. Interestingly, the evaluation of the ontogenetic trajectories suggests that during late ontogeny the facial growth pattern of the Contrebandiers and the Qafzeh children is more similar to that of Neanderthals than it is to recent humans. This suggests that the unique facial growth pattern of Homo sapiens post-dated the MSA. This study is an important step in addressing ontogenetic variability in the African MSA, a period characterized by the origins, emergence, and dispersal of our species, but poorly understood because of the fragmentary and scant human fossil record.

Phylogeographic patterns of Cyphocharax from trans-Andean rivers and northward expansion to lower Central America (Teleostei, Curimatidae).

Phylogenetic analyses of mitochondrial and nuclear data of 31 specimens of Cyphocharax from trans-Andean rivers support the presence of one lineage of Cyphocharax aspilos in Lago Maracaibo and three cryptic lineages of Cyphocharax magdalenae: (1) Cauca-Magdalena and Ranchería, (2) León and Atrato, and (3) Chucunaque-Tuira, Santa María, and Chiriquí basins of Central America. Results suggest that the Serranía del Perijá facilitated Late Miocene cladogenetic events, whereas post-Isthmian C. magdalenae expansion was enabled by gene flow across the lower Magdalena valley and Central American lowlands. Time-calibrated phylogenetics indicate that the C. magdalenae colonized lower Central America in the Pliocene (3.7 MYA; Ma), the divergence Atrato-Magdalena occurred in Late Pliocene (3.0 Ma) and the split Ranchería-Magdalena during the Middle Pleistocene (1.3 Ma). Updated geographic distribution data support the hypothesis that the Cordillera de Talamanca functions as a barrier to northward expansion of C. magdalenae in Central America.

Genetic Variability and Genetic Differentiation of Populations in the Grooved Carpet Shell Clam (Ruditapes decussatus) Based on Intron Polymorphisms

Genetic Variability and Genetic Differentiation of Populations in the Grooved Carpet Shell Clam (Ruditapes decussatus) Based on Intron Polymorphisms

The postcranial variability of Quaternary European rhinoceroses: the case study of Stephanorhinus hundsheimensis from the Middle Pleistocene site of Contrada Monticelli (Apulia, southern Italy)

ABSTRACT Five rhinoceros species, mainly distinguishable through cranial, mandibular and dental morphology, were recognized during the Quaternary across Europe. The postcranial morphology of these taxa is quite variable, with strong superposition among species, especially between Stephanorhinus etruscus and Stephanorhinus hundsheimensis. Here, the complete sample including 25 postcranial bones from the early Middle Pleistocene site of Contrada Monticelli (Apulia, southern Italy) is described and compared through morphological and biometric analyses. A few bones, in addition to cranial and mandibular remains from this site, have been previously referred to Stephanorhinus hundsheimensis. We explored the morphological variability of Stephanorhinus hundsheimensis from Contrada Monticelli against the diagnostic characters described in the literature. The size variation of the Contrada Monticelli sample is also investigated, through a comparison with other Quaternary European rhinoceros samples. Our results indicate a wide morphological variability with several distinct characters and a strong morphological affinity between Stephanorhinus etruscus and S. hundsheimensis. Our results suggest that Stephanorhinus hundsheimensis from Contrada Monticelli is a species with a high degree of intraspecific variability, possibly a hybrid population or a population including two morphotypes of the same species.

Heavily eroded Pleistocene landscape and site-forming processes of the Acheulean artifacts-bearing Holocene sediments, Eastern Desert, Sudan

Since the Middle Pleistocene, the Sahara region has undergone strong environmental changes resulting from climate changes. Dry periods, constituting an ecological barrier to human presence, alternated with wet periods when the Sahara area was covered with green savanna and an extensive network of watercourses, allowing the area to be occupied by hunter-gatherer groups. Responding to the Quaternary climatic changes, hominin dispersal was channeled through vegetated corridors. Such evidence for human settlements connected to Pleistocene green corridors in the Sahara region has been discovered in the research area called EDAR (Eastern Desert Atbara River). This area comprises a cluster of Acheulean and Middle Stone Age (MSA) sites discovered in the fluvial sedimentary context. This manuscript discusses the occurrence of Middle Pleistocene Acheulean artifacts in much younger sediments documented at the site EDAR 6. These Acheulean artifacts are present within thick Holocene calcareous sandy silts formed between 2.7 ka and 8.7 ka based on an optically stimulated luminescence (OSL) chronology, which is also supported by paleomagnetic analysis. The stone gravelly artifacts mantled above the eolian deposits have been known in other Paleolithic sites under the desert environment of Northern Africa. We propose that the relocation of the Palaeolithic artifacts was due to long-lasting erosional and redepositional processes affecting the Acheulean artifacts-bearing sediments since the Middle Pleistocene. We interpret that the cumulative results of the two processes, i.e., the gravel framework dilation and the gravel overpassing, allowed the stone artifacts to be exposed at the surface or incorporated in the Holocene sediment layers.

The Quaternary record of fossil bats in the Iberian Peninsula and the Balearic Islands: Palaeobiogeographical changes and palaeoenvironmental implications

Bats are a highly diversified order of mammals found all over the world; however, their population size and distribution are decreasing rapidly in Europe nowadays. The study of ancient bat populations by means of their fossil record is a valuable source of contextual information for modern bat conservation studies. This paper is a comprehensive review of published bat records in the Iberian Peninsula and the Balearic Islands through Quaternary times, representing the first attempt to update and standardize the knowledge of chiropters in southwestern Europe during this time period. The main goal is to identify changes in bat assemblages that might be correlatable to palaeoclimate and palaeoenvironmental changes. Our data show that the Quaternary record of bats in the area is fragmentary and strongly dependent on the presence of karstic cavities. Thus, a strong preservation bias towards colonial cave-dwelling bats exists, and species with alternative ecological requirements are under-represented. Nevertheless, this work reveals that most of the bats inhabiting the area today were already present in the region from at least the Middle Pleistocene. Interestingly, we observe a frequent association between certain cave-dwelling bats (i.e., Rhinolophus ferrumequinum, Miniopterus schreibersii, Myotis myotis and M. blythii) that is still observed in many caves today; this reflects a stable ecology that has remained undisturbed despite past climatic changes. Within the well-documented periods at the end of the Late Pleistocene and the Holocene, a reduction in some common components of Quaternary assemblages (Rhinolophus species and M. schreibersii) is observed, coinciding with the Late Glacial Maximum and the Northgrippian Neoglacial (a cooling event in the Holocene). Finally, the Balearic record shows interesting palaeobiogeographical characteristics, including some eastern taxa absent in the Iberian Peninsula (Rhinolophus variabilis and R. cf. blasii) as well as an unusual abundance of Rhinolophus hipposideros.

Temporal constraints on magmatic evolution of Acıgöl Bimodal Volcanic Field (Nevşehir, Türkiye)

Neogene to Quaternary post-collisional Central Anatolian volcanism is associated with complex tectonic transition from collisional to extensional regime starting from Miocene. Upper Miocene – Pliocene volcanism is characterized by calc-alkaline effusive products and 10 major ignimbrite sheets. Quaternary represents an evident change in both eruptive styles and the geochemical characteristics of the volcanic products. Pleistocene Acıgöl Bimodal Volcanic Field (ABVF) represents one of the youngest volcanism in Cappadocian Volcanic Province (CPV) and comprises coeval basic and acidic rocks with a Daly Gap between ∼60 % and 72 % SiO2. Pleistocene basaltic volcanism in ABVF is represented by fissural lavas and monogenetic scoria cones, whereas rhyolitic activity is observed as dome/dome flows and pyroclastics including plinian falls and Kumtepe ignimbrite. Basalts of Lower and Middle Pleistocene are silica-undersaturated being nepheline-normative, on the other hand, Upper Pleistocene basic rocks are hypersthene/quartz-normative. Similarly, Lower and Middle Pleistocene rhyolites have higher Sr, Ba, La, than Upper Pleistocene rhyolites which are represented by elevated Y, Th, Nb, Ta and Rb.Petrological data and performed geochemical models show that Lower – Middle Pleistocene primitive basalts can be generated by the partial fusion of an EM-II type spinel peridotite containing amphibole, phlogopite and accessory rutile. Slightly evolved Upper Pleistocene basalts can be formed by crystal fractionation dominated differentiation of earlier basaltic parents. Fractional crystallization of basaltic magmas in high-level segregated chambers with varying amounts of crustal contribution can produce rhyolitic compositions. Furthermore, the amount of crustal contribution diminishes in Upper Pleistocene.

Cryospheric and Oceanographic Evolution in the Arctic Makarov Basin Since the Early Pleistocene Revealed by Bulk Mineral Assemblages

AbstractWe 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.

New Late Pleistocene age for the Homo sapiens skeleton from Liujiang southern China

The emergence of Homo sapiens in Eastern Asia is a topic of significant research interest. However, well-preserved human fossils in secure, dateable contexts in this region are extremely rare, and often the subject of intense debate owing to stratigraphic and geochronological problems. Tongtianyan cave, in Liujiang District of Liuzhou City, southern China is one of the most important fossils finds of H. sapiens, though its age has been debated, with chronometric dates ranging from the late Middle Pleistocene to the early Late Pleistocene. Here we provide new age estimates and revised provenience information for the Liujiang human fossils, which represent one of the most complete fossil skeletons of H. sapiens in China. U-series dating on the human fossils and radiocarbon and optically stimulated luminescence dating on the fossil-bearing sediments provided ages ranging from ~33,000 to 23,000 years ago (ka). The revised age estimates correspond with the dates of other human fossils in northern China, at Tianyuan Cave (~40.8–38.1 ka) and Zhoukoudian Upper Cave (39.0–36.3 ka), indicating the geographically widespread presence of H. sapiens across Eastern Asia in the Late Pleistocene, which is significant for better understanding human dispersals and adaptations in the region.

Phylogeographic Pattern of the Assassin Bug Sycanus bifidus Inferred from Mitochondrial Genomes and Nuclear Genes.

The assassin bug Sycanus bifidus has a wide distribution across southern China. This study explored its distribution and evolution by analyzing mitochondrial and nuclear ribosomal RNA genes, revealing how Pleistocene climate and geological changes shaped its phylogeography. We identified two main clades, A and B, that diverged in the Middle Pleistocene. Hainan Island's populations form a unique group within Clade A, suggesting that the Qiongzhou Strait served as a dispersal corridor during glaciation. Rising sea levels likely separated the Hainan population afterward. Ecological niche modeling showed that both populations have been viable since the last interglacial period, with demographic analyses indicating possible expansions during the Middle and Late Pleistocene, driven by favorable climates. This study highlights the significant effects of Pleistocene sea-level and climatic changes on the distribution and evolution of S. bifidus in China.

MIS5-MIS3 Neanderthal occupations at Amalda III cave (Northern Iberian Peninsula)

The arrival, occupation, and disappearance of Neanderthals in the Cantabrian region is the subject of a long-running debate that continues to this day. Knowledge of the evolution of Neanderthal societies since the end of the Middle Pleistocene in the north of the Iberian Peninsula is greatly impacted by the scarcity of a good chronological framework. This absence of good data creates difficulties in evaluating the cultural adaptations of these populations to environmental changes and their historical dynamics.The Amalda III cave, surveyed in 1983-84, contains a sequence of occupations ranging from the end of MIS5 (Levallois with Mousterian points and bifaces) to the beginning of MIS3 (Vasconian). It is possible to observe substantial changes in the environmental conditions and cultural responses of Neanderthal groups that inhabited the cave. Here we present the first results of the Amalda III sequence, which is currently being excavated by an interdisciplinary team.Our objective is to test, enrich and refine the regional environmental and Neanderthal cultural framework and the transformations that took place between the MIS5 and the MIS3. These new data are compared with the information available from several Middle Paleolithic sites in the region, advancing our understanding of the behavioural adaptations of Neanderthals to different ecological and socio-cultural situations between ca. 100 and 45 kyr BP in the Eastern Cantabrian region. In this way, we will be able to deepen our interpretation of the processes of cultural change of the last groups of Neanderthals that inhabited this region.

Tectonic geomorphology and Quaternary slip history of the Fuyun fault, southwestern Altai Mountains, central Asia

The northwest-trending Altai Mountains of central Asia expose a complex network of thrust and strike-slip faults that are key features accommodating intracontinental crustal shortening related to the Cenozoic India-Asia collision. In this study, we investigated the Quaternary slip history of the Fuyun fault, a right-lateral strike-slip fault bounding the southwestern margin of the Altai Mountains, through geologic mapping, geomorphic surveying, and optically stimulated luminescence (OSL) geochronology. At the Kuoyibagaer site, the Fuyun fault displaces three generations of Pleistocene–Holocene fill-cut river terraces (i.e., T3, T2, and T1) containing landslide and debris-flow deposits. The right-lateral offsets are magnified by erosion of terrace risers, suggesting that river course migration has been faster than slip along the Fuyun fault. The highest Tp2 terrace was abandoned in the middle Pleistocene (150.4 ± 8.1 ka uppermost OSL age) and was displaced 145.5 +45.6/–12.1 m along the Fuyun fault, yielding a slip rate of 1.0 +0.4/–0.1 mm/yr since the middle Pleistocene. The lower Tp1 terrace was abandoned in the late Pleistocene and aggraded by landslides and debris flows in the latest Pleistocene–Holocene (36.7 ± 1.6 ka uppermost OSL age). Tp1 was displaced 67.5 +14.2/–6.1 m along the Fuyun fault, yielding a slip rate of 1.8 +0.5/–0.2 mm/yr since the late Pleistocene. Our preferred minimum slip rate of ~1 mm/yr suggests the Fuyun fault accommodates ~16% of the average geodetic velocity of ~6 mm/yr across the Altai Mountains. Integration of our new Fuyun slip rate with other published fault slip rates accounts for ~4.2 mm/yr of convergence across the Chinese Altai, or ~70% of the geodetic velocity field.

Conserved DNA sequence analysis reveals the phylogeography and evolutionary events of Akebia trifoliata in the region across the eastern edge of the Tibetan Plateau and subtropical China

BackgroundThe eastern edge of the Qinghai‒Tibet Plateau (QTP) and subtropical China have various regions where plant species originate and thrive, but these regions have been the focus of very few integrative studies. Here, we elucidated the phylogeographic structure of a continuous and widespread Akebia trifoliata population across these two regions.ResultsSixty-one populations consisting of 391 genotypes were examined to assess population diversity and structure via network distribution analysis, maximum likelihood phylogenetic tree reconstruction, divergence time estimation, demographic history inference, and ancestral area reconstruction of both conserved internal transcribed spacer (ITS) and chloroplast (rps16) DNA sequences. The results showed that the ITS region was more variable than the rps16 region and could be suitable for studying intraspecific phylogeography. The A. trifoliata population displayed high genetic diversity, genetic differentiation and obvious phylogeographical structure, possibly originating on the eastern QTP, expanding during the last glacial-interglacial cycle, diverging in the early Pleistocene and middle Pleistocene, and extensively migrating thereafter. The migration route from west to east along rivers could be largely responsible for the long-distance dispersal of this species, while three main refuges (Qinba Mountains, Nanling Mountains and Yunnan-Guizhou Plateau) with multiple ice shelters facilitated its wide distribution.ConclusionsOur results suggested that the from west to east long migration accompanying with the minor short reciprocal migration in the south-north direction, and the three main refuges (the Qinba Mountains, Nanling Mountains and Yunnan-Guizhou Plateau) contributed to the extant geographical distribution of A. trifoliata. In addition, this finding also strongly reduced the discrepancy between glacial contraction and postglacial expansion and the in situ survival hypothesis by simultaneously considering the existence of many similar climate-related ecological niches and migration influences.