Stream Valleys Research Articles

Seasonal contamination of surface waters close to an abandoned Sn-W mine, northeast Portugal

The abandoned Ribeira mine consists of Sn-W quartz veins and is located in Tras-os-Montes, northeast Portugal. The mining activities took place on the northern side of the Viveiros stream valley that crosses the mining area. Viveiros is a tributary stream of the Sabor River, which is about 1 km downstream from the mining site. Tailings and rejected materials were deposited on northern hillside of the valley and are exposed to significant weathering and erosion. The Sn-W quartz veins intruded Silurian quartzites and shales and contain cassiterite, wolframite, sphalerite, scheelite, arsenopyrite, pyrite, chalcopyrite, columbite-(Mn) and bismuthinite. Water samples from the Viveiros stream, Sabor River and tailings seasonal drainages were collected. The water has a sodium bicarbonated to calcium sulphated facies, under maximum tailings influence. The sulphate content is low in these waters (up to 145 mg/L). The pH values are close to neutrality, and the maximum electrical conductivity is 303 μS/cm. The metal and semimetals contents in waters show a seasonal variation characterized by low values in the wet and cold season and high contents in the hot and dry season. The contents of Mn, Cu, Zn and Cd found on the tailings seasonal water drainages are higher than those found in the Viveiros stream and Sabor River in the same season. The highest contents of Cd are associated with the highest contents of Zn. These results point to arsenopyrite and sphalerite dissolution as the principal source of metals and semimetals in these waters. The principal component analysis shows a clear spatial and seasonal distinction between the water collected close to the mine influence in the summer period and the other waters. During this period, the Viveiros stream shows As, Cd and Pb contents (e.g. As 0.29; Cd 0.033 and Pb 0.55 mg/L) higher than those permitted by WHO (Guidelines for drinking-water quality, 4th edn (WEB version), 2011) and the Portuguese legislation. Lead, Cd and As are potential threats to the environment due to long-term loadings into the aquatic system. The differences found in the geochemistry of impacted mine water and in its contamination are well expressed if seasonality is considered.

Gilpin in the city: The Baltimore stream valley parks

Walking is an everyday practice that shapes urban space and is shaped by the space in which it occurs. It can create new subjects, new forms of public space and provide alternate readings of the city. This essay examines the significance of walking in the Olmsted Brothers’ 1904 ‘Valley Parks and Parkways’ plan for Baltimore. The transformation of the urban stream valleys into public parks assumed and promoted the concept of recreational walking in a scenic setting, rooted in the tradition of picturesque travel that William Gilpin had popularized in his famous printed tours. The Olmsted Brothers’ 1904 plan gave value to previously overlooked natural corridors and new legibility to the city’s natural systems. Rural scenic values were embraced as part of a larger urban vision. The Baltimore plan illustrates the key role of the landscape in the emergence of comprehensive planning principles, and how it shaped_and was shaped by_everyday social practices.

Deformation style in the damage zone of the Mondy fault: GPR evidence (Tunka basin, southern East Siberia)

The Mondy strike-slip fault connects the W-E Tunka and N-S Hovsgol basins on the southern flank of the Baikal rift system. Ground penetrating radar (GPR) surveys in its damage zone provide constraints on thicknesses, dips, and plunges of fault planes, as well as on the amount and sense of vertical slip. Strike-slip faulting in the southern segment of the Mondy fault within the territory of Russia bears a normal slip component of motion along the W-E and NW planes. These motions have produced negative flower structures in shallow crust appearing as grabens upon Pleistocene fluvioglacial terraces. The amount of normal slip estimated from the displacement of reflection events varies over the area and reaches its maximum of 3.4 m near Mondy Village. In the Kharadaban basin link, left-lateral strike slip displaces valleys of ephemeral streams to 22 m, while normal slip detected by GPR reaches 2.2 m; this normal-to-strike slip ratio corresponds to a direction of ~6° to the horizon. The angles of dips of faults are in the range 75°-79°; the thicknesses of fault planes marked by low- or high-frequency anomalies in GPR records vary from 2.5 to 17.0 m along strike and decrease with depth within a few meters below the surface, which is common to near-surface coseismic motions. Many ruptures fail to reach the surface but appear rather as sinkholes localized mainly in fault hanging walls. The deformation style in the damage zone of the Mondy fault bears impact of the NW Yaminshin fault lying between its two segments. According to photoelasticity, the stress field changes locally at the intersection of the two faults, under NE compression at 38°, till the inverse orientations of principal compression and extension stresses. This stress pattern leads to a combination of normal and left-lateral strike slip components.

Traces of drilling predation in the Badenian Mollusks from the Rakovica stream (Belgrade, Serbia)

The palaeoecology of fossil molluscs of Serbia is insufficiently studied. Drilling predation indicatesinteractive relationships among Middle Miocene Badenian molluscs from the Rakovicasands. These sands are present in the Rakovica stream valley (southern part of Belgrade),andwell-known data about the fauna has existed since the end of the XIX century. The collectedmaterial (one bulk sample) from the sectionwas used for studies that included 2301 shells ofmolluscs (1617 of gastropods and 684 of bivalves). Among them were specimens with predatorydrill holes. Determining the value of drilling frequency (DF) and prey effectiveness (PE) facilitatesidentification of the relationshipbetween shell-drilling predators and their prey. Basedon analysis of the overall association, carnivorous gastropods were dominantin the sample,comprising more than fifty percent (52.32%) of all gastropod specimens. In addition, they constitutea large percentage of the total sample (43.19%). The largest number of victims was observedamong bivalves, which are indicated by a DF of 16.96%. The results were compared withother localities of Miocene age in Paratethys and with studies on the Miocene sediments fromthe Boreal and the Atlantic Provinces. These comparisons show that PE and DF are very similarto results from the Central Paratethys, but that they are significantly higher than in the other areasmentioned.

Age and context of the oldest known hominin fossils from Flores.

Recent excavations at the early Middle Pleistocene site of Mata Menge in the So'a Basin of central Flores, Indonesia, have yielded hominin fossils attributed to a population ancestral to Late Pleistocene Homo floresiensis. Here we describe the age and context of the Mata Menge hominin specimens and associated archaeological findings. The fluvial sandstone layer from which the in situ fossils were excavated in 2014 was deposited in a small valley stream around 700 thousand years ago, as indicated by (40)Ar/(39)Ar and fission track dates on stratigraphically bracketing volcanic ash and pyroclastic density current deposits, in combination with coupled uranium-series and electron spin resonance dating of fossil teeth. Palaeoenvironmental data indicate a relatively dry climate in the So'a Basin during the early Middle Pleistocene, while various lines of evidence suggest the hominins inhabited a savannah-like open grassland habitat with a wetland component. The hominin fossils occur alongside the remains of an insular fauna and a simple stone technology that is markedly similar to that associated with Late Pleistocene H. floresiensis.

Investigation of drainage basin geometry near an anomalously straight reach of the Big Black River, Mississippi, USA

Drainage basin geometry was analyzed in the lower portion of the Big Black River, Mississippi. The study was centered on a reach of the Big Black River that encompasses an anomalous straight reach (ASR) and has morphometric characteristics that differ from those of upstream and downstream reaches. The study area was divided into three reaches, defined by alluvial valley and active floodplain width, sinuosity, and slope. Tributary streams with confluences in the three study reaches were investigated for evidence of surface tilting, and channel and valley slopes and sinuosity were measured. The average stream channel and valley slopes within the middle reach are nearly double those of the upper and lower reaches. Lateral stream migration within the tributary basins was quantitatively analyzed by measuring the asymmetry factor (AF) and transverse topographic symmetry factor (T) indices. While AF results suggest minimal to no lateral migration within the tributaries, the T results show some shifting. The results are inconclusive regarding the possible effect of neotectonic activity in the study area near the ASR. The mean southward migration may indicate a preferred migration direction relative to the general dip of the coastal plain and plunge of the Mississippi Embayment.

Nutrient treatments alter microbial mat colonization in two glacial meltwater streams from the McMurdo Dry Valleys, Antarctica.

Microbial mats are abundant in many alpine and polar aquatic ecosystems. With warmer temperatures, new hydrologic pathways are developing in these regions and increasing dissolved nutrient fluxes. In the McMurdo Dry Valleys, thermokarsting may release both nutrients and sediment, and has the potential to influence mats in glacial meltwater streams. To test the role of nutrient inputs on community structure, we created nutrient diffusing substrata (NDS) with agar enriched in N, P and N + P, with controls, and deployed them into two Dry Valley streams. We found N amendments (N and N + P) to have greater chlorophyll-a concentrations, total algal biovolume, more fine filamentous cyanobacteria and a higher proportion of live diatoms than other treatments. Furthermore, N treatments were substantially elevated in Bacteroidetes and the small diatom, Fistulifera pelliculosa. On the other hand, species richness was almost double in P and N + P treatments over others, and coccoid green algae and Proteobacteria were more abundant in both streams. Collectively, these data suggest that nutrients have the potential to stimulate growth and alter community structure in glacial meltwater stream microbial mats, and the recent erosion of permafrost and accelerated glacial melt will likely impact resident biota in polar lotic systems here and elsewhere.

Analysis of rainfall-induced shallow landslides in Jamne and Jaszcze stream valleys (Polish Carpathians) – preliminary results

Abstract Analysis of rainfall-induced shallow landslides in Jamne and Jaszcze stream valleys (Polish Carpathians) - preliminary results. Preliminary shallow landslide susceptibility mapping of the Jamne and Jaszcze stream valleys, located in the Polish Flysch Carpathians, is presented in the paper. For the purpose of mapping, there were used SINMAP and Iverson’s models integrating infiltration and slope stability calculations. The calibration of the used models parameters, obtained from limited field and laboratory tests, was performed using data from 8-9 July 1997, when as a consequence of a very intense rainfall, 94 shallow landslides were observed on meadows and arable lands. A comparison of the slope stability calculation results and the localisation of the noticed shallow landslides showed satisfactory agreement between localisation of the observed and computed unstable areas. However, it was concluded that better simulation results were obtained using Iverson’s model.

Is there a geomorphic expression of interbasin groundwater flow in watersheds? Interactions between interbasin groundwater flow, springs, streams, and geomorphology

AbstractInterbasin groundwater flow (IGF) can play a significant role in the generation and geochemical evolution of streamflow. However, it is exceedingly difficult to identify IGF and to determine the location and quantity of water that is exchanged between watersheds. How does IGF affect landscape/watershed geomorphic evolution? Can geomorphic metrics be used to identify the presence of IGF? We examine these questions in two adjacent sedimentary watersheds in northern New Mexico using a combination of geomorphic/landscape metrics, springflow residence times, and spatial geochemical patterns. IGF is expressed geomorphically in the landscape placement of springs and flow direction and shape of stream channels. Springs emerge preferentially on one side of stream valleys where landscape incision has intercepted IGF flow paths. Stream channels grow toward the IGF source and show little bifurcation. In addition, radiocarbon residence times of springs decrease and the geochemical composition of springs changes as the connection to IGF is lost.

Hydrogeomorphic controls on hyporheic and riparian transport in two headwater mountain streams during base flow recession

AbstractSolute transport along riparian and hyporheic flow paths is broadly expected to respond to dynamic hydrologic forcing by streams, aquifers, and hillslopes. However, direct observation of these dynamic responses is lacking, as is the relative control of geologic setting as a control on responses to dynamic hydrologic forcing. We conducted a series of four stream solute tracer injections through base flow recession in each of two watersheds with contrasting valley morphology in the H.J. Andrews Experimental Forest, monitoring tracer concentrations in the stream and in a network of shallow riparian wells in each watershed. We found hyporheic mean arrival time, temporal variance, and fraction of stream water in the bedrock‐constrained valley bottom and near large roughness elements in the wider valley bottom were not variable with discharge, suggesting minimal control by hydrologic forcing. Conversely, we observed increases in mean arrival time and temporal variance and decreasing fraction stream water with decreasing discharge near the hillslopes in the wider valley bottom. This may indicate changes in stream discharge and valley bottom hydrology control transport in less constrained locations. We detail five hydrogeomorphic responses to base flow recession to explain observed spatial and temporal patterns in the interactions between streams and their valley bottoms. Models able to account for the transition from geologically dominated processes in the near‐stream subsurface to hydrologically dominated processes near the hillslope will be required to predict solute transport and fate in valley bottoms of headwater mountain streams.

Using Multi Techniques Analysis in Biogeoclimatic Ecosystem Classification and Mapping of Mambilla Plateau in Taraba State Nigeria

This work used multi techniques analysis comprises GIS models, geostatistics, clustering analysis as against the traditional single layer thematic approach to characterize Mambilla Plateau, a cold highland in Taraba state of Nigeriainto biogeoclimatic ecosystem zones needed for natural resources management. The principal criteria used in classifying and mapping the ecosystems are: climate and bioclimate data, physiography (slope, relief and aspect), vegetation/landcover data. In classifying and mapping the physiography of Mambilla Plateau, the topographic layer was produced from 90 m NASA/SRTM digital elevation model. Principal component analysis, agglomerative hierarchical cluster analysis (AHC) and geostatistical techniques (Kriging) were applied to develop bioclimatic layer. A combination of vegetation field survey conducted on selected sites, un/supervised classification and the application of NDVI values was used to produce landcover map and delineation of the Plateau into vegetation units. These layers of physiographic, bioclimatic and vegetation were spatially combined using fuzzy (sum) overlay in Arc GIS 10.2 to produce 5 major and 1 subunit biogeoclimatic ecosystem zones on the Mambilla Plateau and the adjoining landscape namely: humid lowland forest/humid shrubby forest, montane forest, escarpment stream valley forest, grass cypress cool mountain and, grass eucalyptus cold high mountain. It is expected that this approach to biogeoclimatic ecosystem mapping shall form the bedrock for vegetal/forest resources management not only in the region but find application especially in most of the highland of the world.

Drought and vegetation analysis in Tarsus River Basin (Southern Turkey) using GIS and Remote Sensing data

<p>In this study, the effects of topographic variables on drought and vegetation in dry season have been examined. Distributions of dry conditions in Tarsus River Basin were derived using the NDVI, NDMI indexes and LST (Land Surface Temperature) from landsat8 image bands.</p><p>There is large difference in elevation in the study area. Local climatic conditions are formed under the influence of altitude and morphological structure. Narrow and deep valleys in the topography create more moderate temperature/moisture conditions and are the main distribution area of tall forest vegetation. High radiation in the highest plateau system and, extreme temperature/moisture values led short-lived herbaceous vegetation to spread. Due to high insolation/temperature and restricted marine affect, establishment of scrub vegetation can be observed both in mid-elevation and south-sloping plateau of the study area. Anthropogenic agricultural fields form the land surface with the potential of high temperature/evapotranspiration rate in harvesting periods. Broadleaf plant species spread in areas close to the base of the valley stream. Plantation forest has been created in areas of near-shore sand dunes and very small delta (marsh).</p><p>Variability in topography also increases the width of the combination of factors that shape the vegetation. This also enables the number of taxa to increase and unusual taxa to co-exist.</p>

Unchanged Residential Area System in Bukchon(北村), Seoul since the 18th century Bukchon(北村), Seoul since the 18th century

Bukchon, Seoul is area enclosed by a mountain range and to the North is high and to the South is low. The inside is made up of the five lower valleys and every valley streams flowing. The Administrative District Names of each valley were Ganghwa-bang, Yangdeokbang, Gahoe-bang, Anguk-bang, Jingjang-bang, Gwangwang-bang from east in the Joseon Dynasty. Inside each valley, there was a naturally formed village and each village(坊) had a culture of autonomous residents. That culture of each Bang(坊) is created by the royal family and nobility who has not a financial difficulties or not required efforts to avoid citizen labor(坊役). Hanseongbu(modern Seoul) citizens organized Gye(契)-Unit on the basis of human bonds and a spatial homogeneity in oder to perform their citizen labor in the 17th and 18th centuries. But because Bukchon people was able to avoid or exempt citizen labor from social status, they did not organize Gye-Unit. As a result, there was organized into 1Bang-1Gye by administrative districts without experiencing conflict divided into several Gye-Units. Bukchon could be maintained as a non-commercial residential areas like early Joseon Dynasty thanks to the system of 1valley-1Bang(village)-1Gye. Due to this, the culture of Bukchon became increasingly exert great force and it functioned as a power for holding the social status of residents. Since the 18th century, though Hanseogbu was turned commercial city, Bukchon was still as unchanged residential area, due to topography, location, social status construction, village culture etc.

The importance of forests along submontane stream valleys for bird conservation: The Carpathian example

SummaryThe biodiversity and naturalness of forests that cover stream valleys in submontane areas have not been investigated as intensively as riparian forests along large lowland rivers. In this study we compared data on total bird assemblages and on selected indicator species detected in forests along submontane stream valleys (‘Vall’) with those detected in forests covering submontane slopes and tops in the foothills (‘Hill’) of the Western Carpathians, considering also environmental characteristics of the studied locations. The aim of this study was to verify the hypothesis that forests along submontane stream valleys harbour significantly richer and more diverse bird communities and that they are an important habitat for rare and threatened species. We found that the species richness, abundance of birds and bird diversity were almost twice as high in ‘Vall’ than in ‘Hill’ locations and that indicator species mostly or exclusively inhabit ‘Vall’ locations. Moreover, species diversity was highly and positively correlated with higher tree species diversity and a higher amount of large trees and dead wood, but negatively correlated with logging intensity. The results of our study confirmed that forested river valleys in submontane areas play an important role as refugia both for rare and endangered bird species as well as for the whole bird assemblage. This study is the first to present an assessment of this type of habitat for birds in the Western Carpathians. Forests along submontane stream valleys, if protected or unmanaged, could be treated as reference areas for nature and biodiversity conservation.

Overview of Hydrologic and Geologic Investigations Conducted in Canaan Valley, West Virginia

Abstract Canaan Valley (hereafter, the Valley), a unique wetland complex set in the Allegheny Highlands of northeastern West Virginia, has been the subject of several investigations by the US Geological Survey (USGS). These projects include studying the surface-water hydrology and processes affecting dissolved oxygen, groundwater hydrology, wetland biogeochemistry, and the formation of peat. Additionally, recent revisions of the region's geologic maps have enhanced our understanding of the Valley's surface rocks. The Valley's streams typically conduct dilute calcium- and magnesium-bicarbonate type waters that are low in alkalinity, nutrients, and dissolved solids. The Blackwater River and its major tributaries, the Little Blackwater River and the North Branch of the Blackwater River, are low-gradient streams. Other tributaries are high-gradient streams that originate on the Valley's sides and fall rapidly to the Valley floor before joining the Blackwater River and the major tributaries. Generally, low-gra...

소쇄원(瀟灑園)에 내재된 치유성(治癒性)

This study sought to examine Soshaewon as an assumed healing space for Yang, San-Bo who experienced negative emotions as he underwent the political strife of Gimyosahwa. It examined healing energy inherent in Soshaewon which were accumulated through long-term experience, intuitions and customs. And, this study was based on the analysis of the drawings, Soshaewon48poems, and neurologists's research on the effects of buildings and spaces on humans' brain and minds. It was first found that these three sections-Soshaejeong, Kwangpoonggak, and Jewoldang-simultaneously formed diverse visual structures and ample scenic elements. Second, the valley stream circulatory walking(movement) and resting (halt), allowing the walker to emphasize deeply with Nature. Third, there was an interaction between buildings, including Soshaejeong and Aeyangdan (sunshine), Kwangpoonggak and valley stream (sound), and Jewoldang and Maedae (fragrance), and Nature. All these gave Soshaewon a space for creating diverse ample sensation, allowing it to serve as an emotion healing place.

The Whole Story. Bridging the Gap between Landscape-archaeological Data from Drylands and Wetlands

Detailed historical reconstructions require high-quality data. In the traditionally densely settled higher and drier Pleistocene sandy areas (‘drylands’) of the North European Plain (the European aeolian sand belt) and comparable regions elsewhere evidence-based reconstructions are hampered by poor preservation of archaeological remains and archaeologically relevant deposits. This problem can be partially solved by combining, on a microregional level, dryland data with data from nearby wetland pockets (‘wetlands’),in particular stream valleys. This asks for an integrated and systematic inventory of all available data. For this purpose an instrument was developed: the Landscape-Land use Diagram (LLAND). Because data from dry and wet contexts are to some degree supplementary, integrated analysis is essential for obtaining information on the full range of economic and ritual practices. This is demonstrated by research carried out in the valley of the small river Regge (the Netherlands), the results of which are being treated as a stratified landscape-archaeological sample. This paper does not focus on cultural interpretation but on methodology, specifically the potential of data and the benefits of an integrated approach.

Middle Palaeolithic land use in Dutch and Belgian Limburg: Integrating data from surface sites

The European Middle Palaeolithic archaeological database is rich, but is biased towards evidence that originates in stratified sites. In many river catchments, prevalent and often ignored evidence for Middle Palaeolithic occupation is found in palimpsest lithic assemblages on the surface. By way of a case study, this paper addresses the problem of how to integrate lithic artifact assemblage data from such contexts to complement an often unbalanced picture of long-term land use. Analysis of a sample of Middle Palaeolithic surface assemblages from south–southwest facing edges of plateaus and terraces in Dutch and Belgian Limburg yields data suitable for comparison and integration with those from stratified assemblages associated with the wider Maas River valley floor. Sample size and artifact class diversity relationships account for sample size effects and numerically summarize patterns of inter-site fragmentation of core reduction sequences and differential artifact discard, arguably indicators of regional mobility and land use. Variability in artifact class diversity among assemblages also indicates differences in site occupational frequency. When viewed from a long-term diachronic perspective, integrated evidence from cumulative and spatial palimpsests suggests that land use behavior was complex, dynamic, and varied according to topographic factors in the research area. Lack of chronological resolution, variable site formation processes and conditions of artifact recovery complicate detailed interpretation of land use patterns. Despite these problems, results suggest that throughout the Middle Palaeolithic in the research area some plateau and terrace localities were ‘persistent places’ frequently re-occupied for a variety of purposes, while other similarly situated sites and localities more closely associated with river and stream valleys appear to have been occupied less frequently for a more limited range of activities.

Modelling the Last Glacial Maximum environments for a refugium of Pleistocene biota in the Russian Altai Mountains, Siberia

Abstract Recent botanical and zoological studies have suggested that the Altai Mountains in southern Siberia are an important refugium of the last glacial biota that used to be widespread across northern Eurasia before the Pleistocene–Holocene transition. To obtain insights into the history of this relict biota, we modelled the spatial distribution of habitats during the Last Glacial Maximum (LGM) in the Russian Altai. We prepared a map of the current vegetation of this area based on the ground-truthed remote sensing data, and modelled the distribution of the current vegetation types using the Random Forest technique with climatic predictors. The models were projected onto the CCSM3 model of the LGM climate for the Russian Altai and interpreted for 72% of its area because the remaining part is supposed to have been glaciated during the LGM. The models projected LGM predominance of desert-steppe across most of the non-glaciated area of the Russian Altai, probably associated with areas of typical steppe, tundra grasslands and some other habitat types, including forest patches in stream valleys. It is likely that during the LGM, these habitats supported the cold-adapted open-landscape biota. In the Holocene, most of the previous grassland area changed into forest or forest-steppe and the Pleistocene biota retreated, with the exception of the Chuya Basin and the Ukok Plateau in the southeast, where the habitat change was very small and desert-steppe and associated vegetation types remained preserved. This refugial area is currently rich in the relict Pleistocene species. A different history was suggested for the precipitation-rich area in the northernmost Altai (north of Lake Teletskoye), where the LGM models suggested occurrence of patches of open forest of Larix sibirica and Pinus sibirica in forest-tundra and forest-steppe landscapes. These forests may have provided the LGM refugium for the temperate forest species that currently occur in this precipitation-rich area.

News from the north: A late Middle Palaeolithic site rich in handaxes on the Drenthe–Frisian till plateau near Assen, the Netherlands; first results of a trial excavation

The first Middle Palaeolithic artefacts to turn up in situ in boulder sand (erosional residue of glacial till) were found in 2011. The open-air site is located on the Saalian till plateau in the northern Netherlands, not far from the city of Assen, the capital of the province of Drenthe. The finds from a trial excavation comprise flakes, blades, cores and retouched tools. The latter category consists predominantly of handaxes, but a few side-scrapers and backed knives are also present. Apart from erratic Baltic flint, of which most artefacts are made, raw materials include quartzitic sandstone, quartzite and, remarkably, hälleflinta (‘rock-flint’). The assemblage is exceptional because of the many handaxes that dominate the tool spectrum, leading the authors to suggest that butchering activities played a major role in the formation of the assemblage. One of the reasons for Neanderthals to frequent this location, which is situated near a stream valley close to the confluence with a small tributary, might be the presence of relatively good-quality flint nodules and fairly large slabs of hälleflinta. The site is one of the northernmost Middle Palaeolithic occurrences in the Netherlands – in Europe as well – and obviously postdates the Saalian glaciation (MIS 6). ‘Assen’ most likely dates to MIS 3 or MIS 5a/5c of the Weichselian. The presence of many relatively small (sub)cordiform and (sub)triangular handaxes indicates a cultural affiliation with the Mousterian of Acheulian Tradition, Type A. The site is situated near the northern limit of the occupation range of Middle Palaeolithic hominins, and the lithic assemblage is comparable to that from several other sites in the northern part of the North European Plain.