Holocene Age Research Articles

Middle Pleistocene genome calibrates a revised evolutionary history of extinct cave bears

Palaeogenomes provide the potential to study evolutionary processes in real time, but this potential is limited by our ability to recover genetic data over extended timescales.1 As a consequence, most studies so far have focused on samples of Late Pleistocene or Holocene age, which covers only a small part of the history of many clades and species. Here, we report the recovery of a low coverage palaeogenome from the petrous bone of a ∼360,000 year old cave bear from Kudaro 1 cave in the Caucasus Mountains. Analysis of this genome alongside those of several Late Pleistocene cave bears reveals widespread mito-nuclear discordance in this group. Using the time interval between Middle and Late Pleistocene cave bear genomes, we directly estimate ursid nuclear and mitochondrial substitution rates to calibrate their respective phylogenies. This reveals post-divergence mitochondrial transfer as the dominant factor explaining their mito-nuclear discordance. Interestingly, these transfer events were not accompanied by large-scale nuclear introgression. However, we do detect additional instances of nuclear admixture among other cave bear lineages, and between cave bears and brown bears, which are not associated with mitochondrial exchange. Genomic data obtained from the Middle Pleistocene cave bear petrous bone has thus facilitated a revised evolutionary history of this extinct megafaunal group. Moreover, it suggests that petrous bones may provide a means of extending both the magnitude and time depth of palaeogenome retrieval over substantial portions of the evolutionary histories of many mammalian clades.

A central European alluvial river under anthropogenic pressure: The Ohře River, Czechia

Detailed geomorphic evaluation, drill coring, and analysis of floodplain sediments, along with geophysical imaging, were used to study the evolution of the youngest terraces and palaeo-meanders in the lower reach of the Ohře River. Floodplain sediment dating was performed by optically simulated luminescence and via the examination of sediment contamination from historical mining of metals in the river catchment. Two river segments were studied. In the upper segment, the Žatec area, the trunk channel persistently incised from the Early Holocene to ca. 2 ka, and in historical times the meandering channel changed to a low sinuous channel in a narrow channel belt. The terraces and palaeo-meanders in the Žatec area are younger than indicated in the geological maps, by one to two orders of magnitude. In the lower segment, the Písty area, 60 km downstream, approximately half of the sediments in the floodplain transect are the Early to Middle Holocene age and the other half are younger than approximately 1,000 years, in particular from the last five centuries. The deposits of the current channel belt in the Písty area are coarser (mostly sandy in the top metre) than in the rest of the floodplain (mostly silty in the top metre), indicating that the river must have undergone a substantial transformation in the last few centuries. We hypothesise that the trigger of this change was upstream channel straightening and lateral stabilisation, which reduced the amount of river-transported materials. Although the river catchment has been subjected to anthropogenic activity (including intense agriculture in the lower reaches), the river does not show enhanced aggradation.

Geospatial assessment of groundwater arsenic contamination in the Holocene aquifers of Bengal Delta from western parts of the Bhaghirathi River in West Bengal, India

The spatial and subsurface distribution of groundwater arsenic (As) and iron (Fe) in tubewell water were studied with the help of geospatial technique in Purbasthali Blocks I and II of Purba Bardhaman district in Bengal Delta of West Bengal. About 50.40% of tubewell samples (N = 127) have As above the WHO guidelines’ value (> 10 μg/l). Among these contaminated tubewells, about 82.81% tubewells are installed within 60 m depth. All the samples (N = 127) have Fe concentration above 300 μg/l. Maximum concentrations of As and Fe in tubewell samples are 374 μg/l and 17,600 μg/l, respectively. Mean values of As and Fe concentrations are 48 μg/l and 4016 μg/l, respectively. About 29.92% and 33.86% of samples have As and Fe above mean values, respectively. The correlation between As and Fe is significantly positive (R = 0.618) and presence of high concentration (17,600 μg/l) of dissolved Fe indicates strong reducing condition of the aquifers. Maximum number of samples (34.64 %) are from 21 to 40 m depth. Most of the As-contaminated tubewells are located within the depth of 21 to 40 m in the Holocene Newer Alluvium aquifers. Static water level (SWL) depth 10.1 to 15 m below ground surface, occurring in most part of the Katwa Formation, is found to be As-contaminated. Arsenic pollution in the Holocene aquifers is mostly confined in Katwa Formation. Sijua Formation is almost As-safe in groundwater which is in the upper Pleistocene to lower Holocene in age. Most of the As-contaminated tubewells in Katwa Formation are located in the Holocene Newer Alluvium and spatially associated with meander cut-offs, paleo-meander scars, abandoned channels, and back swamp areas.

Site formation process and megamammal bone radiocarbon dates in Campo Laborde (Pampas of Argentina): Contribution towards a research methodology

Dating bone collagen has been problematic in the Argentinean Pampas. Many bone samples do not have collagen or have poor preservation giving collagen of questionably quality, in many cases it is contaminated by humic substances. The combination of these factors has produced suspicious results, leading to the proposition of the Holocene survival in the region of the extinct Pleistocene megamammals such as the Megatherium Holocene ages from the Campo Laborde site. However, new dates from the same sample, purified from humates with XAD-2 resin, gave results of ~10,650 14C years BP. In this article, we apply different methodological procedures (chemical, geoarchaeological and taphonomic analysis) in order to reconstruct the formation at the Campo Laborde the site and identify the processes and agents that affected its chronology. The previously obtained Early Holocene ages of megafauna bones resulted from the interrelation of various factors as physical and chemical weathering, humification processes linked to pedogenesis, and diagenetic processes. In sum, they caused the degradation of collagen and the subsequent contamination by fulvic acids from the overlaying soil, which classic pretreatment techniques could not remove. We conclude that the obtained results do not support the Holocene survival of the megafauna in the Pampas.

PROCESSOS FLUVIOMARINHOS ASSOCIADOS À FORMAÇÃO DA ILHA RASA, SUL DA BAÍA DE MARAPATÁ, NORDESTE DO PARÁ, BRASIL

As ilhas assumem expressivo destaque na paisagem estuarina paraense; contudo, a maior parte delas apresenta gênese não claramente definida. A fim de investigar os fatores de formação da ilha Rasa, situada na foz do rio Tocantins, estuário do rio Pará, o presente trabalho se apoia em feições sedimentares identificadas em um testemunho de sedimento coletado no interior da ilha. Neste trabalho, a integração faciológica e a interpretação de seus ambientes deposicionais, em associação aos eventos climáticos reportados para a região, subsidiaram a proposição de modelo morfogenético. O modelo aqui proposto sugere que a ilha Rasa possui idade tardio-holocênica e consistia, incialmente, de barras arenosasque evoluíram sob o efeito de processos fluviais, inerentes à rede de drenagem e marinhos, articulados às mudanças no clima e nível do mar. Esses processos afetaram o suprimento de sedimento e a distribuição da cobertura vegetal, influenciando a configuração do setor estuarino e contribuindo para a formação de ilhas proximais.
 Palavras-chave: barra arenosa, estuário, nível relativo do mar, ambiente sedimentar, rioTocantins.

Analysis of Late Pleistocene megafauna and puparia from the Lent dredging site, province of Gelderland (the Netherlands)

Abstract More than 900 vertebrate bones, ranging from Late Pleistocene to Holocene in age, have been identified in a collection that was recovered by a single dredging operation for the construction of artificial lakes near Lent (Nijmegen, province of Gelderland, the Netherlands). The Late Pleistocene assemblage comprises mainly Weichselian glacial fauna such as mammoths, reindeer and bison. Some Eemian fauna is represented as well, e.g. straight-tusked elephant. The abundance of certain species over others suggests that preservation bias had a considerable impact on this assemblage, while its time-averaged nature resulted in overrepresentation of certain species. A case study is here conducted on a fragmentary skull of a subadult woolly mammoth bull with embedded blowfly puparia. Some of these puparia are fully developed, indicating prolonged exposure of the mammoth carcass.

Geomorphology, Stratigraphy and Tectonics of the Mesopotamian Plain, Iraq: A Critical Review

The Mesopotamian Plain is part of the Mesopotamia which extends for vast area bigger than the plain. The plain is almost flat and vast lowland, which has clearly defined physiographic boundaries with the other surrounding physiographic provinces. The plain is a huge accumulation geomorphologic unit, where the fluvial, lacustrine, and the Aeolian landforms prevail; the fluvial units being the abundant among others. However, estuarine and marine forms also are developed, but restricted to the extreme southeastern reaches of the plain. The Mesopotamian Plain is covered totally by Quaternary sediments among which the fluvial origin is the most prevailing and more specifically the flood plain sediments. The flood plain sediments are the Holocene in age, whereas the Pleistocene sediments are restricted to alluvial fan sediments and river terraces. The flood plain sediments cover majority of the Mesopotamian Plain, whereas the alluvial sediments are restricted to the northern–eastern, western and southern peripheral parts only. Different geomorphological features indicate the Neotectonic activity in the plain, such as migrations of rivers due to growing of subsurface anticlines. The extreme southeastern part is covered by the tidal flat and sabkha sediments. Marshes and shallow depressions are also covered by the Holocene sediments which are contaminated by the Aeolian sediments. Mesopotamian Plain is a part of the Mesopotamian Foredeep which is a part of the Zagros Foreland Basin including the Zagros Fold-Thrust Belt. It is large continuously subsiding basin since the Upper Miocene (11.62 Ma). The plain shows no structural features on the surface, except the main fault escarpment representing the part of Abu Jir Active Fault Zone. However, the rolling topography, in the northern parts of the plain indicates subsurface anticlines that are still growing up, such as Balad, Samarra, Tikrit and Baiji anticlines indicating the Neotectonic activity. Moreover, many buried subsurface anticlines are present in different parts of the plain. All of them are growing anticlines and have caused continuous shift to Tigris and Euphrates rivers and their distributaries indicating the Neotectonic activities. The minimum and maximum subsidence amounts in the plain since the Upper Miocene are zero and –2500 m, respectively.

Coprophilous fungal spores: non-pollen palynomorphs for the study of past megaherbivores

Abstract Spores from coprophilous fungi are some of the most widely used non-pollen palynomorphs. Over the last decades, these spores have become increasingly important as a proxy to study the Pleistocene and Holocene megafauna. Although the number of types used in palaeoecology is relatively small, there is a wide range of coprophilous fungal taxa whose utility in palaeoenvironmental reconstruction remains under-researched. However, environmental and taphonomic factors influencing preservation and recovery of these spores are still poorly understood. Furthermore, our understanding of whether and how spores are transported across the landscape is limited. Dung fungal spore presence appears to correlate well with megaherbivore presence. However, depending on the site, some limitations can remain to quantitative reconstructions of megaherbivore abundance from dung fungal spore records. The presence of dung fungal spores is often more significant than their absence and variation in abundance with time should be interpreted with caution. Correlation with other proxies may provide a promising way forward. The majority of studies using dung fungal spores as an indicator for large herbivore abundance are of records of Late Pleistocene and Holocene age, with a focus on Late Quaternary megafaunal extinction. However, more research could potentially extend records further back in time.

РАЗНОВОЗРАСТНЫЕ ДРЕВНИЕ АЛАСЫ НА СЕВЕРО-ВОСТОКЕ РОССИИ

Thermokarst lakes and alases are widespread in the North-East of Russia. These structures are part of Quaternary deposit of the region and mostly of Holocene age. The alas complex of the older age is less common. Here we present the study of alas complex sections as old as Lower – Upper Neopleistocene from the Laptev Sea coast (Oyagoss yar, Shirokostan peninsula). The principal composition of these structures of different ages is quite similar. Their formation is correlated with warm intervals when the moisture content increased. Melting of the ice-rich sediment took place locally. Accumulation of the melted water increased the melting and lead to formation of separated thermokarst depressions where succession of the lake-bog-soil sediments with ice-wedge casts (pseudomorphosis) began to accumulate. Current research expands the knowledge about distribution of the alas complex in the north-eastern Russia, allows to recognize its features (the presence of tabers, lacustrine sediments with a complex of pseudomorphs along the ice wedge, the increase in grain size of lacustrine sediments from the center to the periphery of the basins, a large number of values of allochthonous peat in the middle and autochthonous in the top of alas strata), and suggests how to extract paleogeographic information from this type of deposit.

Textural and oceanographic aspects of the sandy beaches of South coast of Santa Catarina, Brazil

This study aims to describe the textural and oceanographic aspects of the foreshore zone of the beaches located between the municipalities of Passo de Torres and Balneario Rincao, at South coast of Santa Catarina. Oceanographic and textural parameters were collected at 41 sites, arranged on 22 beaches that extend out on 77,4 km of coastline. The field work was conducted in December 2007. The Sysgran software analyzed the textural data, revealing high homogeneity of grain size, predominance of fine sand, with quartzose sediments, reddish brown color (2.5YR5/3) in 66% of the samples and brown color (10YR5/3) in 34% of the samples, besides reducing amount of organic matter and biodetritic carbonate. In general, the sediments are well sorted, mesokurtic and with skewness approximately symmetrical. Regarding the source area, it should be noted that the coastal plain of the South coast of Santa Catarina comprises a wide barrier-lagoon depositional system of Holocene age, in which the sediments in general show high maturity. Regarding the coastal oceanographic aspects, the rectilinear shape of the coastline, as well as the predominant dissipative morphodynamic stage and a system of well-developed coastal dunes in most of the sites examined, corroborate with the textural and compositional homogeneity resulting from the frequency and intensity of the marine dynamic agents, winds and supply of lithoclastic sediments.

Geological characteristics of potential geoparks in the South central of Viet Nam

The coast of South Central Vietnam from Danang city to Binh Thuan province is about 1200 km long, distributing many geological and geomorphic heritages of high scientific values, including representativeness, integrity and rarity, deserving to build a national geopark such as: i) Ly Son volcanic island geopark is formed up of volcanic materials mainly explosive in the late Holocene age; ii) Phu Yen coastal geopark possessed geological and geomorphic diversity with the presence of ancient Pre-Cambrian rocks; iii) Red Sand Plateau and Rocky Coast Ninh Thuan- Binh Thuan geopark has shaped by intrusive and extrusive igneous rock tips and characterized by majestic red sand plateau. The three geological parks will be established as a legal basis for the conservation of geological and geomorphological heritage for the research, education and local economic development.

Pollen as a potential indicator of the origin of massive ice in northwest Siberia

AbstractPollen and spores collected from massive ice bodies in northwest Siberia were studied with the aim to provide a cryogenic indication of their origin. We discuss perennial massive ice, which may occur as lenses, layers, or irregular masses in the frozen ground and may be buried or intrasedimental. Pollen assemblages in massive ice deposits of Holocene age indicated a nonglacial origin of the ice. Pollen assemblages from glacial snow cover and snow patches on tundra were analyzed to reveal signs of buried ice. This approach allowed us to assess the nature of several massive ice bodies as intrasedimental and buried, and demonstrated how pollen may be used as an indicator for the origin of massive ice in northwest Siberia.

Constraining coseismic earthquake slip using Structure from Motion from fault scarp mapping (East Helanshan Fault, China)

This study uses fault scarps to investigate past earthquakes and the potential seismic hazard of the East Helanshan Fault (EHF). The EHF is a Holocene active normal fault located at the complex transition from compression in the northeastern corner of the Tibetan Plateau to apparently east-west extension in the west margin of Ordos Block, as implied by the Yinchuan Faulted Basin and its boundary normal faults. Repeated normal faulting events, including the 1739 CE event on the EHF, offset alluvial fans of Late Pleistocene and Holocene age and formed remarkable fault scarps, especially along its Suyukou and Hongguozi segments. We selected three fault sections in the Suyukou and Hongguozi segments, where fault scarps of different heights are well preserved on different terrace surfaces. By using Structure-from-Motion-Multiview Stereo (SfM-MVS) techniques on Unmanned Aerial System (UAS) imagery, we acquired high-quality topography of the selected fault sections. Detailed mapping and surveying of the offset geomorphic features and their associated fault scarps, with distinct free faces and multiple slope breaks, suggest that surface-rupturing earthquakes occurred repeatedly along the EHF. Densely spaced cross scarp topographic profiles were extracted to evaluate the vertical slip distributions using newly acquired SfM-derived topography. Through statistical analysis of the displacement dataset, we constrain multiple earthquake events and their cumulative offsets on the Suyukou and Hongguozi segments. Large earthquakes on the EHF produced different characteristic co-seismic slips on the Suyukou segment and the Hongguozi segment of ~2.6 m and ~1.7 m, respectively. The scaling relationships between the moment magnitude, surface rupture length, and the average co-seismic slip indicate possible magnitudes within a range of Mw 6.8–7.2, and a potential magnitude of approximately Mw 7.4 as an upper bound in the case of a multi-fault rupture along the EHF. This study demonstrates the UAS-based SfM photogrammetry as an effective means for mapping fault zone topography in areas of sparse vegetation, as well as its potential for identifying and measuring subtle geomorphic features associated with past earthquakes.

Quaternary megafauna from the Dnieper alluvium near Kaniv (central Ukraine): Implications for biostratigraphy

Subfossil remains of the Quaternary megafauna from two Ukrainian natural history collections stored at Kaniv Nature Reserve and the National Museum of Natural History NAS of Ukraine were examined. Most of the bones were collected in 1965–1966, in the building pit and the gateway of the Kaniv hydroelectric power plant. The fauna is represented at least by ten taxa (Gulo gulo, Mammuthus trogonterii chosaricus, Mammuthus intermedius, Coelodonta antiquitatis, Megaloceros giganteus, Alces alces, Bison priscus, Cervus elaphus, Capra cf. ibex, and Equus ferus). Skeletal parts are represented mainly by skulls, long bones, horns, and tusks. Based on the species composition of proboscideans, at least part of the faunal assemblage is dated by the end of the Middle Pleistocene (Dnieper Stage = Saale, Warta, MIS 6), but majority of bones could be older or younger (Late Pleistocene and Holocene age) due to the alluvial origin of accumulation.

A Y-chromosomal survey of Ecuador’s multi-ethnic population reveals new insights into the tri-partite population structure and supports an early Holocene age of the rare Native American founder lineage C3-MPB373

Ecuador is a multiethnic and pluricultural country with a complex history defined by migration and admixture processes. The present study aims to increase our knowledge on the Ecuadorian Native Amerindian groups and the unique South American Y-chromosome haplogroup C3-MPB373 through the analysis of up to 23 Y-chromosome STRs (Y-STRs) and several Y-SNPs in a sample of 527 Ecuadorians from 7 distinct populations and geographic areas, including Kichwa and non-Kichwa Native Amerindians, Mestizos and Afro-Ecuadorians. Our results reveal the presence of C3-MPB373 both in the Amazonian lowland Kichwa with frequencies up to 28 % and, for the first time, in notable proportions in Kichwa populations from the Ecuadorian highlands. The substantially higher frequencies of C3-MPB373 in the Amazonian lowlands found in Kichwa and Waorani individuals suggest a founder effect in that area. Notably, estimates for the time to the most recent common ancestor (TMRCA) in the range of 7.2–9.0 kya point to an ancient origin of the haplogroup and suggest an early Holocene expansion of C3-MPB373 into South America. Finally, the pairwise genetic distances (RST) separate the Kichwa Salasaka from all the other Native Amerindian and Ecuadorian groups, indicating a so far hidden diversity among the Kichwa-speaking populations and suggesting a more southern origin of this population. In sum, our study provides a more in-depth knowledge of the male genetic structure of the multiethnic Ecuadorian population, as well as a valuable reference dataset for forensic use.

Evidence for a large-magnitude Holocene eruption of Mount Rittmann (Antarctica): A volcanological reconstruction using the marine tephra record

In Antarctica, the near-source exposures of volcanic eruption deposits are often limited as they are not well preserved in the dynamic glacial environment, thus making volcanological reconstructions of explosive eruptions extremely challenging. Fortunately, pyroclastic deposits from explosive eruptions are preserved in Southern Ocean sediments surrounding Antarctica, and the tephrostratigraphy of these sequences offers crucial volcanological information including the timing and tempo of past eruptions, their magnitude, and eruption dynamics. Here we report the results of a tephrostratigraphy and tephrochronology study focused on four sediment cores recovered from the Wood Bay area in the western Ross Sea, Antarctica. In all these sedimentary sequences, we found a well-stratified primary tephra of considerable thickness, up to 80 cm, hereafter named the Aviator Tephra (AVT). According to the characteristics of the tephra deposit and its distribution, the AVT was associated with an eruption of considerable intensity, potentially representing one of the largest Holocene eruptions recorded in Antarctica. Based on the major and trace element geochemistry and the mineral assemblage of the tephra, Mount Rittmann was identified as the source of the AVT. A Holocene age of ∼11 ka was determined by radiocarbon dating organic material within the sediments and 40Ar-39Ar dating of alkali-feldspar crystals included in the tephra. Eruption dynamics were initially dominated by hydromagmatic magma fragmentation conditions producing a sustained, relatively wet and ash-rich eruptive cloud. The eruption then evolved into a highly energetic, relatively dry magmatic Plinian eruption. The last phase was characterized by renewed efficient magma-water interaction and/or collapse of the eruptive column producing pyroclastic density currents and associated co-ignimbritic plumes. The distal tephra deposits might be linked to the widespread lag breccia layer previously identified on the rim of the Mount Rittmann caldera which share the same geochemical composition. Diatoms found in the sediments surrounding the AVT and the primary characteristics of the tephra indicate that the Wood Bay area was open sea at the time of the eruption, which is much earlier than previously thought. AVT is also an excellent tephrostratigraphic marker for the Wood Bay area, in the Ross Sea, and a useful marker for future synchronization of continental ice and marine archives in the region.

Are the widespread scatters of stone artefacts on dune surfaces in southeastern arid Australia really late Holocene in age?

Vast numbers of stone artefact clusters (commonly called artefact scatters) occur on dune surfaces throughout southeastern arid Australia, virtually all of them undated. They were interpreted by researchers in the 1980s and 1990s as being mainly of late Holocene age on the basis of their surface or near-surface locations and the composition of their assemblages, which include backed artefacts, tulas and unifacial points. In this article, we analyse dated archaeological sites in the Roxby dunefield to test the reliability of this interpretation. Our analyses indicate that we can be confident that most of the artefacts in the many thousands of other recorded but undated sites in this dunefield are of late Holocene age. Throughout the region, the post-LGM geomorphic histories of dunes in relation to their archaeological records were broadly similar, allowing us to conclude that, on the balance of probabilities, earlier researchers working throughout the southeast arid zone were correct to conclude that the sites on the surfaces of these dunes were essentially late Holocene in age. Abbreviations: BA+T+UP: backed artefacts, tulas and unifacial points combined; ENSO: El Niño Southern Oscillation; LGM: last glacial maximum; OH&S: occupational health and safety

Groundwater recharge processes in an Asian mega-delta: hydrometric evidence from Bangladesh

Groundwater is used intensively in Asian mega-deltas yet the processes by which groundwater is replenished in these deltaic systems remain inadequately understood. Drawing insight from hourly monitoring of groundwater levels and rainfall in two contrasting settings, comprising permeable surficial deposits of Holocene age and Plio-Pleistocene terrace deposits, together with longer-term, lower-frequency records of groundwater levels, river stage, and rainfall from the Bengal Basin, conceptual models of recharge processes in these two depositional environments are developed. The representivity of these conceptual models across the Bengal Basin in Bangladesh is explored by way of statistical cluster analysis of groundwater-level time series data. Observational records reveal that both diffuse and focused recharge processes occur in Holocene deposits, whereas recharge in Plio-Pleistocene deposits is dominated by indirect leakage from river channels where incision has enabled a direct hydraulic connection between river channels and the Plio-Pleistocene aquifer underlying surficial clays. Seasonal cycles of recharge and discharge including the onset of dry-season groundwater-fed irrigation are well characterised by compiled observational records. Groundwater depletion, evident from declining groundwater levels with a diminished seasonality, is pronounced in Plio-Pleistocene environments where direct recharge is inhibited by the surficial clays. In contrast, intensive shallow groundwater abstraction in Holocene environments can enhance direct and indirect recharge via a more permeable surface geology. The vital contributions of indirect recharge of shallow groundwater identified in both depositional settings in the Bengal Basin highlight the critical limitation of using models that exclude this process in the estimation of groundwater recharge in Asian mega-deltas.

Neotectonic Activity of Segmented Alluvial Fans Along Hemr in South Anticline, East Iraq

A quantitative analysis of geomorphic indices was carried out to understand the impacts of tectonics on the geomorphological relief of drainage basins and alluvial fans. Based on field work, satellite images and aerial photographs interpretation, five stages of alluvial fanswere recognized within the study area. Theyare of a coalesced type, forming continuous belt of Bajada, andcovering vast areas whichextend along the southwestern limb of Hemrinanticline. The alluvial fans’ sediments lie unconformably over pre- Quaternary sediments represented by angular unconformity.The earlier stages of the fanswere developed during the Plio- Pleistocene age, whereas the later stage represents the sediments of the Holocene age. Fourdistinct segmented alluvial fans were considered under this study, located within Torsaq and Shosharin basins. They aredeveloped in the first, second and third stagesof alluvial fans. Some morphotectonic parameters were calculated in order to understand the tectonic dynamics of these fans, includingmountain front sinuosity (Smf), ratio of valley floor’s width to height (Vf), fan tilting(β), and drainage basin asymmetry (FA). The results showedless active mountain frontand low uplift,according to the acquired high values of Vf.The fansare tilted towards the west direction, indicating uplift of their eastern parts,whilethe main streams are shifted downstream to the right.

Extreme dispersal or human-transport? The enigmatic case of an extralimital freshwater occurrence of a Southern elephant seal from Indiana.

Elephant seals (Mirounga spp.) are the largest living pinnipeds, and the spatial scales of their ecology, with dives over 1 km in depth and foraging trips over 10,000 km long, are unrivalled by their near relatives. Here we report the discovery of an incomplete Holocene age Southern elephant seal (M. leonina) rostrum from Indiana, USA. The surviving material are two casts of the original specimen, which was collected in a construction excavation close to the Wabash River near Lafayette, Indiana. The original specimen was mostly destroyed for radiometric dating analyses in the 1970s, which resulted in an age of 1,260 ± 90 years before the present. The existence of sediments in the original specimen suggests some type of post depositional fluvial transportation. The prevalent evidence suggests that this male Southern elephant seal crossed the equator and the Gulf of Mexico, and then entered the Mississippi River system, stranding far upriver in Indiana or adjacent areas, similar to other reported examples of lost marine mammals in freshwater systems. Based on potential cut marks, we cannot exclude human-mediated transportation or scavenging by Indigenous peoples as a contributing factor of this occurrence. The material reported here represents by far the northernmost occurrence of a Southern elephant seal in the Northern Hemisphere ever recorded. The unusual occurrence of a top marine predator >1,000 km from the closest marine effluent as a potential extreme case of dispersal emphasizes how marine invasions of freshwater systems have happened frequently through historical (and likely geological) time.