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Objectives: Subbranches of Y‐chromosome haplogroup C2a‐L1373 are founding paternal lineages in northern Asia and Native American populations. Our objective was to investigate C2a‐L1373 differentiation in northern Asia and its implications for Native American origins. Materials and Methods: Sequences of rare subbranches (n = 43) and ancient individuals (n = 37) of C2a‐L1373 (including P39 and MPB373), were used to construct phylogenetic trees with age estimation by BEAST software. Results: C2a‐L1373 expanded rapidly approximately 17.7,000–14.3,000 years ago (kya) after the last glacial maximum (LGM), generating numerous sublineages which became founding paternal lineages of modern northern Asian and Native American populations (C2a‐P39 and C2a‐MPB373). The divergence pattern supports possible initiation of differentiation in low latitude regions of northern Asia and northward diffusion after the LGM. There is a substantial gap between the divergence times of C2a‐MPB373 (approximately 22.4 or 17.7 kya) and C2a‐P39 (approximately 14.3 kya), indicating two possible migration waves. Discussion We discussed the decreasing time interval of "Beringian standstill" (2.5 ky or smaller) and its reduced significance. We also discussed the multiple possibilities for the peopling of the Americas: the "Long‐term Beringian standstill model," the "Short‐term Beringian standstill model," and the "Multiple waves of migration model." Our results support the argument from ancient DNA analyses that the direct ancestor group of Native Americans is an admixture of "Ancient Northern Siberians" and Paleolithic communities from the Amur region, which appeared during the post‐LGM era, rather than ancient populations in greater Beringia, or an adjacent region, before the LGM. [ABSTRACT FROM AUTHOR]

In this article, we apply our analytical theory, published earlier in this journal, to obtain information on the earth surface temperature history from some borehole temperature data. Compared to the results of the five different methods applied to the same temperature data, our method seems to be easier, assumption-free, and yields internally consistent results. The results suggest a cooling a few centuries ago, followed by a continuing warming up to these days, in agreement with a little ice age scenario. [ABSTRACT FROM AUTHOR]

The general picture of Pleistocene stratigraphy in the Outer Coastal Plain of North Carolina has changed significantly in the last five decades owing to new work involving subsurface coring, application of geophysical methods, radiometric and amino-acid dating, chronostratigraphic improvements, and high-resolution paleoenvironmental analyses. A crucial part of this change resulted from the concentration of attention to the thick, relatively complete succession of stratigraphic units within the Albemarle Embayment. Exposures at river banks, borrow pits and smaller excavations to the north and south of the embayment typically do not reveal much of the lateral variation of the familiar, named lithologic units, and successions are not as complete. These limited stratigraphic windows on Pleistocene stratigraphy in the region remain important opportunities for description and interpretation of stratigraphic units, which can be lithologically indistinguishable, but separated by unconformities and associated with different landforms--and therefore should be considered allostratigraphic units. Local exposures need to be analyzed and integrated into the regional stratigraphic framework using multiple methods if possible, in addition to the standard documentation of lithologies and most abundant macrofossils. Much remains to be done involving precise age determinations, correlations of units exposed along rivers and in excavations with allostratigraphic units delineated in the Albemarle Embayment, and matching units to Marine Isotope Stages and ultimately to Quaternary climate cycles. [ABSTRACT FROM AUTHOR]

Abstract The study of two caves from the Serra do Ramalho region is here presented, this is one of the most important karstic areas in Brazil. A taxonomic analysis revealed 29 taxa including Xenarthra, Cetartiodactyla and Carnivora, ranging from Late Pleistocene to Early Holocene. Taphonomic studies reveal taphocoenosis consisting mainly of complete elements, without significant transportation, but also of transported elements, composing spatial-mixed, predominantly in situ-preserved assemblages. The predominance of Xenarthrans found within the caves is probably biased by a taphonomic pattern since these animals would have life habits related to cave environments, therefore with higher chances of preservation. There is evidence of accidental death of the scelidotheriines in Lapa dos Peixes cave, where entrapment of the animals during one or more events of river flooding is pointed as a hypothesis. Deposition took place within different periods of dry and humid climate incorporating bones in clastic and chemical deposits. Cycles of sedimentary deposition and reworking (erosion) may have acted in generating complex and overlapping depositional patterns with time averaging. During depositional phase, while the cave environment was occupied rather by Xenarthrans, parts of other animals were transported in the scope of fluvial systems and gravity loads, as well as by accidental falling or scavengers. The sedimentary deposits are currently being eroded by rain runoff in both caves, causing the reallocation of finer sediments to deeper conduits but the fossils keep close to their original location. This process is exposing a large amount of fossils, allowing extensive sampling which would be impossible with active excavations, since it would require an excessively longer time and damages to the caves. Highlights • Fossils naturally exposed by erosion were studied in two caves from Brazil. • 29 taxa, mostly Xenarthrans, were found with life habits related to caves. • Taphocoenosis mainly of complete elements, but also transported elements. • Dry and humid climates formed clastic and chemical deposits with time averaging. • Low energy erosive phase has transported fine sediments while keeping the fossils in place. [ABSTRACT FROM AUTHOR]

Abstract The Argentinean Mesopotamian region is a plain limited by large rivers, with an interesting environment history and climate changes, especially during late Neogene and Quaternary periods. Within the Mesopotamia, Corrientes Province is particularly attractive due toits current vegetation and geomorphological characteristics where the Eastern-Northwestern migration of the Paraná River has played an important role. This migration in turn, allowed the sedimentation of the main geological units in the Pliocene -Pleistocene interval. The outcrops of the Ituzaingó (Pliocene) and Toropí/Yupoí (late Pleistocene) formations are widely distributed in Corrientes, and include numerous fossil remains of plants, invertebrates, and vertebrates (mainly mammals). Despite the paleontological and stratigraphic studies carried out, the data are still insufficient to reconstruct how the environments varied and how the migration of the Paraná River could have affected the vegetation during the last part of the Cenozoic. In this contribution, the first detailed study of the phytolith assemblages is accomplished, characterizing the Ituzaingó and Toropí/Yupoí formations in order to infer the palaeoclimatic and vegetation changes during the late Cenozoic in this area of the Mesopotamian region. Four sampling localities (BV1, BV2, E1, and E2) were selected in two sites (Bella Vista and Empedrado). The recovered associations were useful for environmental reconstructions. Both formations are fluvial deposits related at different times to the current Paraná River. The phytolith assemblages of the Ituzaingó Fm. evidence the different ways in which the biosilica elements were affected by pre and post-depositional processes. The Toropí/Yupoí Fm. shows well-preserved assemblages that suggest heterogeneous vegetation communities, with wetlands and grasslands to savannas and forests on the floodplain environments under seasonal subtropical climates. Highlights • Ituzaingó and Toropí/Yupoí fms. were related to fluvial environments. • Phytoliths of the Ituzaingó Fm. were affected by pre and post-depositional processes. • Phytoliths are good paleoenvironmental indicators in the Toropí/Yupoí Fm. • Ituzaingó Fm. showed environments with woody and herbaceous vegetation. • Toropí/Yupoí Fm. had floodplain environments with heterogeneous vegetation. [ABSTRACT FROM AUTHOR]

We study the existence of weak solution and semiclassical limit for mixed Dirichlet-Neumann boundary value problem of 1,2,3-dimensional isentropic transient quantum drift-diffusion models for bipolar semiconductors. A time-discrete approximate scheme for the model constructed employing the quantum quasi-Fermi potential is composed of non-degenerate elliptic systems, and the system in each time step has a solution in which the components of carrier's densities are strictly positive. Some stability estimates guarantee convergence of the approximate solutions and performance of the semiclassical limit. [ABSTRACT FROM AUTHOR]

Arctic Ocean trough mouth fans (TMFs) represent a valuable archive of glacial-interglacial sedimentary processes that are especially important when reconstructing pre-Weichselian glaciations that may lack distinct imprints on the shelves. In 2011, we acquired the first high-resolution 3D seismic cube (~3 m vertical and 6 m horizontal resolution) on the continental slope of the SW Barents Sea by use of a P-Cable 3D system, to study in detail the seismic stratigraphy and glacial depositional history of the Bear Island Trough Mouth Fan. This technology provides data with a resolution that, for the first time on the western Barents Sea slope, enables detailed mapping of deposits of different glacial cycles. The dataset provides entire spatially coverage, allowing us to reconcile multiple generations of glacigenic deposits and channel systems. High-resolution 3D seismic data is crucial to describe buried channels, glacial units, as well as low relief landforms such as sediment waves accurately. The 30 km 2 seismic cube is located at the southern flank of the Bear Island TMF at water depths from 592 to 660 m where sandwaves dominate the present seafloor. The data covers the glacially derived stratigraphy in the uppermost ~700 m below the seafloor. We establish a robust stratigraphic framework by interpreting seismic reflectors along 2D tie-in lines to previously well-constrained seismic and well data. We find that our data provide a record of progradation of glacigenic debris flows (GDFs) since MIS 12 (0.5 Ma) to present. Horizon slices reveal a range of gullies and channels at different depths overlying the GDFs. We describe the paleoenvironment and sedimentary processes throughout this time-span (that covers seven glacial cycles) and discuss the impact of the Barents Sea Ice Sheet waxing and waning on erosion, sedimentation, and deposition along the continental slope. Abundant buried gullies were hitherto unknown at the Bear Island TMF, with previous work describing this succession as a debris-flow dominated unit where meltwater-related features are lacking, and interpreting this to represent low average temperatures. By use of the relatively small high-resolution 3D seismic dataset, we provide new evidence for the presence of gullies and channels indicating that periods of ice sheet melting and meltwater runoff existed throughout the middle-late Pleistocene succession. The work offers new insight into the stratigraphic evolution of a continental margin dominated by GDFs and demonstrates the value of high-resolution seismic, such as the P-Cable system, in resolving important details of paleo-slope-environments. [ABSTRACT FROM AUTHOR]

A refined relative sea level (RSL) history spanning the past 14,300 calendar years is described for the Quadra Island area in the northern Strait of Georgia on the Pacific coast of Canada. Here marine shorelines dating to the time of earliest post-glacial emergence are at least 197 m above present-day sea-level at 14,300 years ago. RSL fell rapidly, reaching two to three metres above present-day by 12,000 years ago. A series of raised marine terraces at ca. 4, 10 and 30 m above present day high tide level suggest the rapid fall in RSL during early post-glacial time may have been briefly interrupted by factors such as regional ice advances and recessions and global meltwater pulses generated by climatic variations. A possible minor sea-level transgression of 1–2 m around 12,000 to 11,400 years ago was followed by slow regression to modern levels. This sea-level reconstruction is providing critical input for efficient discovery and cataloging of late Pleistocene and early Holocene archaeological sites on ancient raised shorelines in the region. Integration of the sea-level history with LiDAR imagery has proven successful in locating a number of archaeological sites on these ancient shorelines. [ABSTRACT FROM AUTHOR]

Geological investigations in the southern part of the Polish-Belarusian cross-border area were focused on correlation of main Middle Pleistocene stratigraphic units and on extent of the ice sheet of the Saalian Glaciation. Determination of regional stratotype horizons, establishing new key sites and sections of regional significance for Central Europe were based mostly on vegetation and paleoclimate changes recorded in glacial and interglacial lake deposits. Results of stratigraphical investigations abolished a predominant palaeogeographic image on ice sheet limits in this area. The Saalian maximum ice sheet limit was similar or even less extensive than during the subordinate Warta Stadial. Most of the area between the Middle Vistula in Poland and the Middle Dnieper in Belarus and the Ukraine was ice-free during this glaciation. On the other hand, immense glacial lobes during Saalian in the Middle Vistula and the Middle Dnieper valleys have not advanced presumably in the same time and were fed by ice moving from different parts of Scandinavia. Diversified Pleistocene tectonic uplifting in the area influenced much dynamics of the penultimate ice sheet in this part of Europe. [ABSTRACT FROM AUTHOR]

In the northwestern Lake Tahoe Basin, Pleistocene basaltic and trachyandesitic lavas form a small volcanic field comprising ~1 km³ of lava that erupted from seven vents. Most of these lavas erupted subaerially and produced lava flows. However, where they flowed into an early Lake Tahoe (Proto-Tahoe), they produced deltas consisting of hydrovolcanic breccias as well as pillow lavas draped downslope, pillow breccias, hyaloclastites, and mixtures of lava and wet sediments. Consequently, various former shorelines of Proto-Tahoe are marked by subaerial lava flows overlying subaqueous lava deltas. Isolated explosive interactions produced lapilli tuff cones that built upward from vents on the lake floor or grew as littoral cones where subaerial lava flows crossed the shoreline. Six new 40Ar/39Ar ages define three Pleistocene episodes when lava erupted subaerially and flowed into Proto-Tahoe. Three cycles of canyon damming by lava and downcutting occurred at the outlet of Proto-Tahoe in the Truckee River Canyon. The canyon was dammed at 2.3 Ma by basaltic lavas at Rampart, which raised lake level from 1897 m above sea level to 2048 m. The canyon was again dammed at 2.1 Ma by basaltic lavas at the outlet of ProtoTahoe near Rampart, which raised lake levels from ~1914 m to 2073 m. And finally, the canyon was again dammed at 0.94 Ma by trachyandesitic lavas at Thunder Cliffs, which raised lake level to 2085 m. Hence, ancient shorelines that are nearly 200 m above the present lake level are documented at 0.94, 2.1, and 2.3 Ma. The present outlet of Lake Tahoe through the Truckee River canyon has been operative for at least 2.3 million years. Even though the three lava dams are now eroded away, the repeated construction (and removal by erosion) of lava dams has diminished the erosion and deepening of the Truckee River Canyon that otherwise would have occurred. Hence, the soft-sediment sill of Lake Tahoe has been protected, which has helped to maintain the great depth of the lake (500 m). The timing of this repetitive volcanic activity raises implications for future volcanic eruptions and their hazards. The lake could be dammed by lava again causing extensive shoreline flooding as its level rose, or rapid dam failure could cause extensive downstream flooding along the Truckee River on its path to Reno. [ABSTRACT FROM AUTHOR]

Empirical scaling relationships between known deepwater siliciclastic submarine fan systems and their linked drainage basins have previously been established for modern to submodern depositional systems and in a few ancient, small-scale basins. Comprehensive mapping in the subsurface Gulf of Mexico basin and geological mapping of the North American drainage network facilitates a more rigorous test of scaling relationships in a continental- size system with multiple mountain source terranes, rivers, deltas, slopes, and abyssal plain fan systems formed over 65 m.y. of geologic time. An immense database of drilled wells and high-quality industry seismic data in this prolific hydrocarbon basin provide the independent measure of deepwater fan distribution and dimensions necessary to test source-to-sink system scaling relationships. Analysis of over 40 documented deepwater fan and apron systems in the Gulf of Mexico, ranging in age from Paleocene to Pleistocene, reveals that submarine- fan system scales vary predictably with catchment length and area. All fan system run-out lengths, as measured from shelf margin to mapped fan termination, fall in a range of 10%-50% of the drainage basin length, and most are comparable in scale to large (Mississippi River-scale) systems although some smaller fans are present (e.g., Oligocene Rio Bravo system). For larger systems such as those of the Paleocene Wilcox depositional episodes, fan runout lengths generally fall in the range of 10%-25% of the longest river length. Submarine fan widths, mapped from both seismic reflection data and well control, appear to scale with fan run-out lengths, though with a lower correlation (R² = 0.40) probably due to uncertainty in mapping fan width in some subsalt settings. Catchment area has a high correlation (R² = 0.85) with river length, suggesting that fluvial discharge and sediment flux may be primary drivers of ancient fan size. Validation of these first-order source-to-sink scaling relationships provides a predictive tool in frontier basins with less data. Application to less-constrained early Eocene fan systems of the southern Gulf of Mexico demonstrates the utility for exploration as well as paleogeographic reconstructions of ancient drainage systems. This approach has considerable utility in estimating dimensions of known but poorly constrained submarine fans in the subsurface or exposed in outcrop. [ABSTRACT FROM AUTHOR]

Understanding the links between subducting slabs and upper-plate defor mation is a longstanding goal in the field of tectonics. New 3D seismic sequence stratigraphy, mapped within the Costa Rica Seismogenesis Project (CRISP) seismic-reflection volume offshore southern Costa Rica, spatiotemporally constrains several Pleistocene outer forearc processes and provides clearer connec tions to subducting plate dynamics. Three significant shelf and/or slope erosional events at ca. 2.5-2.3 Ma, 1.95-1.78 Ma, and 1.78-1.19 Ma, each with notable differences in spatial extent, volume removed, and subsequent margin response, caused abrupt shifts in sedimentation patterns and rates. These shifts, coupled with observed deformation, suggest three primary mechanisms for Pleistocene shelf and slope vertical motions: (1) regional subaerial erosion and rapid subsidence linked to the southeastward Panama Fracture Zone triple-junction migration, with associated abrupt bathymetric variations and plate kinematic changes; (2) transient, kilometer-scale uplift and subsidence due to inferred subducting plate topography; and (3) progressive outer wedge shortening accommodated by landward- and seaward-dipping thrust faults and fold development due to the impinging Cocos Ridge. Furthermore, we find that the present-day wedge geometry (to within ~3 km along strike) has been maintained through the Pleistocene, in contrast to modeled landward margin retreat. We also observe that deformation, i.e., extension and shortening, is decoupled from net margin subsidence. Our findings do not require basal erosion, and they suggest that the vertical motions of the Costa Rican outer forearc are not the result of a particular continuous process, but rather are a summation of plate to plate changes (e.g., passage of a fracture zone triple junction) and episodic events (e.g., subducting plate topography). [ABSTRACT FROM AUTHOR]

In this study, luminescence dating of core sediments from the North Bohai Coast (China) was applied to provide a high-resolution chronological constraint, on a better understanding of the Holocene marine-terrestrial interaction. The studied sedimentary sequence contains a terrigenous deposit, a transgressive deposit and a prograding deltaic succession; all are believed to have formed during the late Pleistocene. To establish a reliable luminescence chronology, the luminescence signals of ten samples were investigated in order to quantify the degree of bleaching. This approach involved the use of quartz OSL, K-feldspar infrared stimulated luminescence (IRSL) and post-IR IRSL (pIRIR) ages. The resulting data were then compared with radiocarbon ages. The quartz OSL signals were well-bleached for all the samples, and the feldspar pIRIR 150 and pIRIR 225 signals yielded reliable ages for the pre-Holocene deposits but overestimated ages for late Holocene deposits (<1000 years). Radiocarbon data appeared to slightly overestimate the age of the young Holocene samples, therefore the chronological framework was established using quartz OSL ages. The early-mid Holocene transgressive deposits are relatively thin, which was attributed to the low-gradient relief and weak riverine fluvial input. Rapid deltaic progradation with high sedimentation rates over the last millennia, was revealed by the quartz OSL age results. This was supported by historical records for this section of the coastline. Episodic deposition around 700 years ago most likely triggered by frequent flooding events, was highlighted by the clustered OSL ages. While the sediment increment was 2.7 × 10 4  m 3  a −1 for the period of ∼6–1 ka, this increased considerably to 9.1 × 10 6  m 3  a −1 during the rapid progradation of the last millennium. The increase appears related to winter monsoon enhancement and human activity during the last 1000 years. [ABSTRACT FROM AUTHOR]

Thirty-five stratigraphic section exposed along the Mukah-Selangau road in the Mukah-Balingian area have been studied. Sedimentological and palynological data have been integrated to gain a better insight into the depositional architecture of the area. Broadly, the Mukah-Balingian area is dominated by fluvial, floodplain and estuarine related coal-bearing deposits. The Balingian, Begrih and Liang formations have been described and interpreted in terms of seven facies association. These are: FA1 – Fluvial-dominated channel facies association; FA2 – Tide-influenced channel facies association; FA3 – Tide-dominated channel facies association; FA4 – Floodplain facies association; FA5 – Estuarine central basin-mud flats facies association; FA6 – Tidal flat facies association and FA7 – Coastal swamps and marshes facies association. The Balingian Formation is characterised by the transgressive phase in the base, followed by a regressive phase in the upper part. On the basis of the occurrence of Florscheutzia trilobata with Florscheutzia levipoli , the Early to Middle Miocene age has been assigned to the Balingian Formation. The distinct facies pattern and foraminifera species found from the samples taken from the Begrih outcrop imply deposition in the intertidal flats having pronounced fluvio-tidal interactions along the paleo-margin. Foraminiferal data combined with the pronounced occurrence of Stenochlaena laurifolia suggest at least the Late Miocene age for the Begrih Formation. The internal stratigraphic architecture of the Liang Formation is a function of a combination of sea level, stable tectonic and autogenic control. Based on stratigraphic position, the Middle Pliocene to Pleistocene age for the Liang Formation is probable. The Balingian, Begrih and Liang formations display deposits of multiple regressive-transgressive cycles while the sediments were derived from the uplifted Penian high and Rajang group. [ABSTRACT FROM AUTHOR]

For the first time, the Upper Pleistocene Girkanian sediment subhorizon was recorded in the submarine boreholes of the northern Caspian Sea and its radiocarbon age was estimated. Girkanian beds lying at a depth of 25 m beneath the seafloor were studied by lithological, biostratigraphical, seismic and radiocarbon dating methods. They were distinguished based on the characteristic assemblage of Mollusca ( Didacna subcatillus , D. cristata , Corbicula fluminalis , etc.). This assemblage is similar to its onshore analogue and differs from the fauna of the underlying Upper Khazarian ( D. surahanica , D. nalivkini , etc.) and overlying Lower Khvalynian ( D. ebersini , D. parallella , D. protracta , etc.) layers. Acoustic profiling indicates the ubiquity of the horizon in the northern Caspian Sea, as seen from the clear correlation between boreholes. AMS 14 C dating has shown that the age of the Girkanian deposits exceeds 55 ka. Their real age haze to be about 80 ka. The obtained results on identification and age estimation of Girkanian beds are an important contribution to the verification of the Upper Pleistocene stratigraphy of the Caspian Sea region. [ABSTRACT FROM AUTHOR]

In north-eastern France, red deer (Cervus elaphus L.) populations were rebuilt from a few hundred individuals, which have subsisted in remote valleys of the Vosges mountains, and to a lesser extent from individuals escaped from private enclosures; at present times, this species occupies large areas, mainly in the Vosges Mountains. In this study, we examined the population dynamics of red deer in the Vosges Mountains using ancient and contemporary mitochondrial DNA (mtDNA) from 140 samples (23 ancient + 117 modern) spanning the last 7’000 years. In addition, we reconstructed the feeding habits and the habitat of red deer since the beginning of agriculture applying isotopic analyses in order to establish a basis for current environmental management strategies. We show that past and present red deer in the Vosges Mountains belong to mtDNA haplogroup A, suggesting that they originated from the Iberian refugium after the last glacial maximum (LGM). Palaeogenetic analysis of ancient bone material revealed the presence of two distinct haplotypes with different temporal distributions. Individuals belonging to the two haplotype groups apparently occupied two different habitats over at least 7’000 years. AM6 correlates with an ecological type that feeds in densely forested mountain landscapes, while AM235 correlates with feeding in lowland landscapes, composed of a mixture of meadows and riverine, herb-rich woodlands. Our results suggest that red deer of north-eastern France was able to adapt, over the long term, to these different habitat types, possibly due to efficient ethological barriers. Modern haplotype patterns support the historical record that red deer has been exposed to strong anthropogenic influences as a major game species. [ABSTRACT FROM AUTHOR]

Kiseiba Oasis and depression are located in southern Egypt between the Selima Sand Sheet to the west and the Nile to the east, an important area that hosted Late Cenozoic drainage, Middle Pleistocene lakes, and numerous Paleolithic and Neolithic cultural sites. A synthesis of orbital data, field surveying and near-surface stratigraphy provides new insights into the Quaternary history of this region. Shuttle Imaging Radar data show a complex of fluvial channels that are due to stringers of surficial fluvial lag, subsurface fluvial deposits, and areas of deep alluvium. Three topographic surfaces are described: 1) the Atmur El-Kibeish, above 230 m elevation, which displays a linear pattern of light radar returns, possibly formed from northeast drainage; 2) the Acheulean Surface, at 200 m elevation, that has dark radar patterns resulting from thick alluvium bounded by pebble sand and calcrete strata, and 3) the Kiseiba Surface, below 190 m, that has a complex series of surface and subsurface fluvial and aeolian sediments. Initial drainage from the Early through Middle Pleistocene was to the northeast, which may have lasted through the Last Interglacial. Later reworking of sediments during the Last Glacial Maximum and the Holocene resulted in topographic inversion, with any subsequent local drainage on the Kiseiba Surface to the southwest, towards the Kiseiba Scarp. [ABSTRACT FROM AUTHOR]

Bahia state is widely known for the presence of fossiliferous deposits of Late Pleistocene – early Holocene. Although most studies in the state have been carried out on cave environments, studies concerning natural tank deposits have been expanded in the last few years, particularly in other states of Northeast Brazil. Therefore, the present work aims to study two new natural tanks: “Lagoa das Abelhas” and “Lagoa do Rancho”, in Guanambi municipality, south-central Bahia, Brazil. The identified taxa include representatives of Xenarthra ( Eremotherium laurillardi , cf. Glossotherium sp., Pachyarmatherium brasiliense , Glyptodontinae, Propraopus sulcatus , Pampatherium humboldti , and Holmesina paulacoutoi ), Notoungulata (Toxodontidae), Proboscidea, Perissodactyla ( Tapirus terrestris and Equus ( Amerhippus ) neogaeus ), and Cetartiodactyla (Camelidae). The taphonomic analysis allowed the fossiliferous deposit from Lagoa das Abelhas to be classified as an ex situ assemblage, while the Lagoa do Rancho deposit was interpreted as a peripheral assemblage. Based on its paleofaunal composition, the landscape of the Guanambi region would have comprised open areas with pastures and patches with arboreal elements. The 14 C radiocarbon dating results point to ages of 22,230 ± 55 years for the Lagoa das Abelhas and 16,020 ± 40 years for the Lagoa do Rancho tanks, indicating that the Guanambi paleofauna lived during the Last Glacial Maximum, in a drier phase of the Late Pleistocene. [ABSTRACT FROM AUTHOR]

The recognition of past climatic fluctuations in sedimentary sequences in central Mexico is relevant for understanding the forcing mechanisms and responses of climatic system in the northern American tropic. Moreover, in this active volcanic setting the sedimentary record preserves the history of past volcanic activity. Climatic and environmental variability has been documented for the last tenths of thousands of years from the upper lacustrine sediments in Chalco basin. A series of cores drilled down to 122 m depth in this basin offer a long, continuous and high resolution record of past climatic changes of the last ca. 150 kyr in this region. Here we present the detailed lithostratigraphy and some physical properties (magnetic susceptibility and density) of the master sequence. Sedimentary components and their abundance were identified and quantified in smear slides and direct core observations. Age model is based on 13 14 C and one 230 Th/U dates. Based on their facies association seven lithostratigraphic units were defined, which reflect the main stages of lake Chalco evolution. These phases closely match the marine isotopic stages. The data reveal that at the end of MIS6 Chalco was a relatively deep and stratified freshwater lake. During MIS5 the depositional environment fluctuated between low lake stands to marshy and marginal playa settings with sporadic flooding events, and severe arid periods resulted in aerial exposure of lake sediments. Low lake stands persisted during MIS4 and MIS3, with minor fluctuations towards slightly deeper phases. The Last Glacial Maximum (LGM) and the deglacial period (21-13 kyr) are characterized by intense volcanism. The early and mid-Holocene high calcareous content and alkaline-subsaline lake suggest dry conditions. The fluctuations of lake levels inferred provide the basis for future paleoclimatic works. [ABSTRACT FROM AUTHOR]

We consider the problem of quantum and stochastic confinement for drift-diffusion equations on domains Ω ⊂ R d . We obtain various sufficient conditions on the behavior of the coefficients near the boundary of Ω which ensure the essential self-adjointness or stochastic completeness of the symmetric form of the drift-diffusion operator, − 1 ρ ∞ ∇ ⋅ ρ ∞ D ∇ . The proofs are based on the method developed in [31] for quantum confinement on bounded domains in R d . In particular for stochastic confinement we combine the Liouville property with Agmon type exponential estimates for weak solutions. [ABSTRACT FROM AUTHOR]

The wave equation □ g M , a ψ = 0 on subextremal Kerr spacetimes ( M M , a , g M , a ) , 0 < | a | < M , does not admit real mode solutions, as was established by Shlapentokh-Rothman. In this paper, we show that the absence of real modes does not persist under the addition of an arbitrary short-range non-negative potential V to the wave equation or under changes of the metric g M , a in the far away region of M M , a (retaining the causality of the stationary Killing field T there). In particular, we first establish, for any 0 < | a | < M , the existence of real mode solutions ψ to equation □ g M , a ψ − V ψ = 0 , for a suitably chosen time-independent real potential V with compact support in space, satisfying V ≥ 0 . Exponentially growing modes are also obtained after perturbing the potential V . Then, as an application of the above result, we construct a family of spacetimes ( M M , a , g M , a ( d e f ) ) which are compact in space perturbations of ( M M , a , g M , a ) , have the same symmetries as ( M M , a , g M , a ) and moreover admit real and exponentially growing modes. These spacetimes contain stably trapped null geodesics, but we also construct a more complicated family of spacetimes with normally hyperbolic trapped set, admitting real and exponentially growing modes, at the expense of having conic asymptotics. The aforementioned results are in contrast with the case of stationary asymptotically flat (or conic) spacetimes ( M , g ) with a globally timelike Killing field T , where real modes for equation □ g ψ − V ψ = 0 are always absent, giving a useful zero-frequency continuity criterion for showing stability for a smooth family of equations □ g ψ − V λ ψ = 0 , with λ ∈ [ 0 , 1 ] and V 0 = 0 . We show explicitly that this criterion fails on Kerr spacetime. [ABSTRACT FROM AUTHOR]

Sediment cores and seismic reflection data acquired from the eastern basin of Lake Kivu, Rwanda reveal extensive limnologic variations due to changes in regional climate and basin structure. The eastern basin of the lake contains a sedimentary wedge which is > 1.5 km in thickness on its western side, and basal sediments are estimated to be at least 1.5 million years old. Sediments are likely to be thicker and older than this in the northern, Congolese basin of the lake. Above the ∼300 m iosbath only a thin layer of Holocene sediments are observed indication that this may have been the lake’s high stand prior to that time. There are at least three erosional unconformities interpreted as desiccation or near-desiccation events which are estimated to have occurred at ∼475 ka, ∼100 ka, and ∼20 ka; the two most recent of these low stages likely developed during the African Megadrought and Last Glacial Maximum (LGM) periods. Following the LGM, the water levels rose to form a ∼100 m deep lake with its surface ∼370 m below the current lake level. The lake remained near that level for several thousand years and during this time the Virunga Volcanic Province expanded. At ∼12.2 ka a change to wetter climate conditions rapidly filled the lake to spill out of the Bukavu Bay basin southward toward Lake Tanganyika. Tephra sampled from the cores show that there have been at least 24 large local volcanic events since the early Holocene lake transgression. [ABSTRACT FROM AUTHOR]

This paper presents the latest results of archaeological research in Epigravettian deposits of Blazi Cave in north-central Albania. This Epigravettian site is the first of its kind in Albania with a large sample of stone artifacts, faunal remains and dating material. The study material stems from the last remaining Late Pleistocene deposits in this cave and therefore characterizes the site in its totality. AMS 14 C dates place the cultural layers between 18 and 17 ka cal. BP. This age model coupled with the density of anthropogenic remains attests an intensive use of the shelter by hunter-gatherers in the final phase of the Last Glacial Maximum. The radiocarbon results place the Blazi data into the early phase of the Late Adriatic Epigravettian complex. This chronology is corroborated by certain technological and typological traits identified within the stone tool sample. Analysis of the faunal remains suggests a repeated use of the shelter in the warmer summer period. Blazi Cave functioned as a specialized ibex hunting site and therefore fits into a larger complex of task localities in the wider region. [ABSTRACT FROM AUTHOR]

In this paper, I identify two general positions with respect to the relationship between environment and natural selection. These positions consist in claiming that selective claims need and, respectively, need not be relativized to homogenous environments. I then show that adopting one or the other position makes a difference with respect to the way in which the effects of selection are to be measured in certain cases in which the focal population is distributed over heterogeneous environments. Moreover, I show that these two positions lead to two different interpretations-the Pricean and contextualist ones-of a type of selection scenarios in which multiple groups varying in properties affect the change in the metapopulation mean of individual-level traits. Showing that these two interpretations stem from different attitudes towards environmental homogeneity allows me to argue: (a) that, unlike the Pricean interpretation, the contextualist interpretation can only claim that drift or selection is responsible for the change in frequency of the focal trait in a given metapopulation if details about whether or not group formation is random are specified; (b) that the traditional main objection against the Pricean interpretation-consisting in arguing that the latter takes certain side-effects of individual selection to be effects of group selection-is unconvincing. This leads me to suggest that the ongoing debate about which of the two interpretations is preferable should concentrate on different issues than previously thought. [ABSTRACT FROM AUTHOR]

A study is conducted on the impact of plasma compressibility on the stability of drift ballooning modes. The two-fluid and four-field model developed by Hazeltine et al. [Phys. Fluids 28, 2466 (1985)] is employed in this study. Results of linear numerical simulations show that finite compressibility destabilizes ballooning modes which are otherwise stable due to the ion diamagnetic drift effect. A systematic study reveals that the parallel compressibility originating from the two-fluid effect, rather than the drift-acoustic wave coupling suggested by Hastie et al. [Phys. Plasmas 10, 4405 (2003)], plays the most important role in destabilizing the ballooning modes. An analytic evaluation of the dispersion relation underpins the strong sensitivity of this parallel compressibility term in the ballooning mode stability. The potential impact of this new understanding on the physics of small edge localized modes is discussed. [ABSTRACT FROM AUTHOR]

Generation of sheared zonal flow by low-frequency coupled electrostatic drift and ion-acoustic waves is presented. Primary waves of different (small, intermediate, and large) scales are considered, and the appropriate system of equations consisting of generalized Hasegawa-Mima equation for the electrostatic potential (involving both vector and scalar nonlinearities) and equation of parallel to magnetic field ions motion is obtained. It is shown that along with the mean poloidal flow with strong variation in minor radius mean sheared toroidal flow can also be generated. According to laboratory plasma experiments, main attention to large scale drift-ion-acoustic wave is given. Peculiarities of the Korteweg-de Vries type scalar nonlinearity due to the electrons temperature non-homogeneity in the formation of zonal flow by large-scale turbulence are widely discussed. Namely, it is observed that such type of flows need no generation condition and can be spontaneously excited. [ABSTRACT FROM AUTHOR]

An open-source sea ice drift algorithm for Sentinel-1 SAR imagery is introduced based on the combination of feature tracking and pattern matching. Feature tracking produces an initial drift estimate and limits the search area for the consecutive pattern matching, which provides small- to medium-scale drift adjustments and normalised cross-correlation values. The algorithm is designed to combine the two approaches in order to benefit from the respective advantages. The considered feature-tracking method allows for an efficient computation of the drift field and the resulting vectors show a high degree of independence in terms of position, length, direction and rotation. The considered pattern-matching method, on the other hand, allows better control over vector positioning and resolution. The preprocessing of the Sentinel-1 data has been adjusted to retrieve a feature distribution that depends less on SAR backscatter peak values. Applying the algorithm with the recommended parameter setting, sea ice drift retrieval with a vector spacing of 4 km on Sentinel-1 images covering 400 km x 400 km, takes about 4 min on a standard 2.7 GHz processor with 8GB memory. The corresponding recommended patch size for the pattern-matching step that defines the final resolution of each drift vector is 34 x 34 pixels (2.7 x 2.7 km). To assess the potential performance after finding suitable search restrictions, calculated drift results from 246 Sentinel-1 image pairs have been compared to buoy GPS data, collected in 2015 between 15 January and 22 April and covering an area from 80.5 to 83.5° N and 12 to 27° E. We found a logarithmic normal distribution of the displacement difference with a median at 352.9m using HV polarisation and 535.7m using HH polarisation. All software requirements necessary for applying the presented sea ice drift algorithm are open-source to ensure free implementation and easy distribution. [ABSTRACT FROM AUTHOR]

Deposits formed between the Neogene/Pleistocene transition and into the Early Pleistocene have been studied, mainly on the basis of drillings and at rare, small outcrops in the lowland part of Polish territory. At the Bełchatów lignite mine (Kleszczów Graben, central Poland), one of the largest opencast pits in Europe, strata of this age have long been exposed in extensive outcrops. The present paper is based on our field studies and laboratory analyses, as well as on research data presented by other authors. For that reason, it can be seen as an overview of current knowledge of lowermost Pleistocene deposits at Bełchatów, where exploitation of the Quaternary overburden has just been completed. The results of cartographic work, sedimentological, mineralogical and palynological analyses as well as assessment of sand grain morphology have been considered. All of these studies have allowed the distinction of three Lower Pleistocene series, i.e., the Łękińsko, Faustynów and Krzaki series. These were laid down in fluvial environments between the end of the Pliocene up to the advance of the first Scandinavian ice sheet on central Poland. The following environmental features have been interpreted: phases of river incision and aggradation, changes of river channel patterns, source sediments for alluvia, rates of aeolian supply to rivers and roles of fluvial systems in morphological and geological development of the area. The two older series studied, i.e., Łękińsko and Faustynów, share common characteristics. They were formed by sinuous rivers in boreal forest and open forest environments. The Neogene substratum was the source of the alluvium. The younger series (Krzaki) formed mainly in a braided river setting, under conditions of progressive climatic cooling. Over time, a gradual increase of aeolian supply to the fluvial system can be noted; initially, silt and sand were laid down, followed by sand only during cold desert conditions. These fluvio-periglacial conditions are identified in the foreground of the advance of the oldest ice sheet into this part of central Poland. The series studied have been compared with other fluvial successions which accumulated in the Kleszczów Graben during subsequent glaciations so as to document general changes in fluvial systems as reactions to climatic evolution. Thus, a palaeoenvironmental scenario has emerged which could be considered to be characteristic of central Poland during the Early Pleistocene. [ABSTRACT FROM AUTHOR]

In order to investigate the potential seismic vibrations effect on two-phase flow in an annular channel, experimental tests with air-water two-phase flow under horizontal vibrations were carried out. A low-speed eccentric-cam vibration module capable of operating at motor speed of 45–1200 rpm ( f  = 0.75–20 Hz) was attached to an annular channel, which was scaled down from a prototypic BWR fuel sub-channel with inner and outer diameters of 19.1 mm and 38.1 mm, respectively. The two-phase flow was operated in the ranges of 〈 j f 〉 = 0.25–1.00 m/s and 〈 j g 〉 = 0.03–1.46 m/s with 27 flow conditions, and the vibration amplitudes controlled by cam eccentricity ( E ) were designed for the range of 0.8–22.2 mm. Ring-type impedance void meters were utilized to detect the area-averaged time-averaged void fraction under stationary and vibration conditions. A systematic experimental database was built and analyzed with effective maps in terms of flow conditions (〈 j g 〉-〈 j f 〉) and vibration conditions ( E - f and f - a ), and the potential effects were expressed by regions on the maps. In the 〈 j g 〉-〈 j f 〉 maps, the void fraction was found to potentially decrease under vibrations in bubbly flow regime and relatively lower liquid flow conditions, which may be explained by the increase of distribution parameter. Whereas and the void fraction may increase at the region closed to bubbly-to-slug transition boundary under vibrations, which may be explained by the changes of drift velocity due to flow regime change from bubbly to slug flows. No significant change in void fraction was found in slug flow regime under the present test conditions. [ABSTRACT FROM AUTHOR]

Planktonic foraminiferal and ice-rafted debris count data, as well as the mean size of mineral particles of the 10-63 μm fraction (sortable silt, $$\overline {SS} $$ ) were used as a proxy for surface and near-bottom paleocurrent intensity variations. The data obtained support our hypothesis about turbiditic origin of the lower (80-370 cm) section of the studied AMK-4515 core. Stratigraphic subdivision of the upper section (0-80 cm) makes it possible to allocate two marine isotope stages (MIS) covering the last 27 ka. The main intervals of the North Atlantic Polar Front (PF) migrations were recorded: south of the modern PF position during early MIS 2 (24-27 ka) with PF presence in the study area during MIS 2 (20-24 ka); south of the study area during the last glacial maximum (18-20 ka). Influence of the near-bottom currents within the investigated interval led to beginning of the channel-related drift formation on the northern slope of the southern channel of the Charlie-Gibbs Fracture Zone. There is a weak relationship between intensity of near-bottom contour currents and long-term climatic cyclicity. However, intervals corresponding to Heinrich events coincide with decrease in bottom currents activity. [ABSTRACT FROM AUTHOR]

A megaslump at Batagaika, in northern Yakutia, exposes a remarkable stratigraphic sequence of permafrost deposits ~50–80 m thick. To determine their potential for answering key questions about Quaternary environmental and climatic change in northeast Siberia, we carried out a reconnaissance study of their cryostratigraphy and paleoecology, supported by four rangefinder 14C ages. The sequence includes two ice complexes separated by a unit of fine sand containing narrow syngenetic ice wedges and multiple paleosols. Overall, the sequence developed as permafrost grew syngenetically through an eolian sand sheet aggrading on a hillslope. Wood remains occur in two forest beds, each associated with a reddened weathering horizon. The lower bed contains high amounts of Larix pollen (>20%), plus small amounts of Picea and Pinus pumila, and is attributed to interglacial conditions. Pollen from the overlying sequence is dominated by herbaceous taxa (~70%–80%) attributed to an open tundra landscape during interstadial climatic conditions. Of three hypothetical age schemes considered, we tentatively attribute much of the Batagaika sequence to Marine Oxygen Isotope Stage (MIS) 3. The upper and lower forest beds may represent a mid–MIS 3 optimum and MIS 5, respectively, although we cannot discount alternative attributions to MIS 5 and 7. [ABSTRACT FROM AUTHOR]