Loess Cover Research Articles

Field measurements of water storage capacity in a loess–gravel capillary barrier cover using rainfall simulation tests

A 30 m long × 20 m wide capillary barrier cover (CBC) test site was constructed at the Jiangcungou landfill in Xi’an, China. The cover consisted of a compacted loess layer with a thickness of 0.9 m underlain by a gravel layer. After the cover surface was kept bare and exposed to natural climate conditions for nearly 5 months, one artificial rainfall event was implemented at the site. Vegetation was established at the test site after the first rainfall event. Four months later, a second artificial rainfall event was applied to the surface of the vegetated site. The pore-water pressures (PWPs) and volumetric water contents (VWCs) of the cover were monitored using jet-filled tensiometers and time-domain reflectometry moisture probes, respectively. Surface runoff and percolation were measured using field collection devices. The field measurements demonstrated a more rapid response of PWPs to the rainfall compared to the response of the VWCs. Percolation was observed when the PWPs near the interface reached the water-entry value of the gravel at local points. At that moment, the measured VWC near the interface was less than the VWC according to the water-entry value. The observation indicated that preferential flows took place in the compacted loess during the rainfall. As a result, the maximum water storage capacity was not reached at the onset of percolation. When percolation ceased, the average PWP near the interface decreased below the water-entry value, while the VWC near the interface was higher than that at the onset of percolation. Water storage at the completion of percolation was approximately 5% greater than that at the onset of percolation. Compared with the monolithic loess cover, the loess–gravel CBC increased the available water storage capacity by 41% at the completion of percolation. Vegetation had an insignificant influence on water storage capacity.

A modified depositional hypothesis of the Hanjiang Loess in the southern Qinling Mountains, central China

Geomorphologically, alluvial deposits in river systems are expected to be older on higher terraces than on the lower terraces. However, loess deposits of aeolian origin may also occur on the surface of terrace systems and as seen in the Chinese Loess Plateau (CLP). Such loess is continuously, rather than episodically deposited. This study presents numerous dating results of loess cover on the Hanjiang River terrace system in the southern Qinling Mountains, an atypical loess deposit belt outside of the CLP. We name this “Hanjiang Loess”. Results indicate that the Hanjiang Loess deposited on the high, middle, and low terraces are also the oldest, old, and most recent, respectively, apparently analogous with alluvial expectations. We thus propose a modified depositional hypothesis, whereby terrace loess reflects the deposition of aeolian loess and other material, subsequent fluvial reworking. This depositional hypothesis should also be applicable to loess deposits on the river terraces in the Xiashu Loess, Quaternary Reticulate Red Clay, and Quaternary Red Clay in southern China, and other atypical loess areas outside of the CLP.

Environment influences and extinguish technology of spontaneous combustion of coal gangue heap of Baijigou coal mine in China

This paper has tested the CO source of 2521 fully mechanized face through SF6 gas and contrapuntally made the comprehensive control technology based on loess cover, loess isolation and grouting slurry. In fire extinguishing process, loess isolation is used to prevent spontaneous combustion area from enlarging, loess cover reduces the air leakage in the spontaneous combustion area of Coal Gangue Heaps, and borehole grouting and trenching grouting reduce heat quantity of the spontaneous combustion area. According to the detection of spontaneous combustion field parameters, above technical measures have controlled the spontaneous combustion areas of coal gangue in Baijigou Coal Mine.

Sedimentation of Holocene tufa influenced by the Neolithic man: An example from the Sąspowska Valley (southern Poland)

Abstract A complex of inactive tufas, the thickness of which reaches 3.5 m, was studied in the lowermost segment of the Sąspowska Valley in the Krakow Upland (Ojcow National Park, Poland). Five fluvial tufa barrages were recognized. They are composed of moss tufa and stromatolitic tufa accompanied with oncoidal rudstone and detrital tufa. Interbarrage ponded areas were filled with detrital tufa, lutite, and subordinately oncoidal rudstone, limestone gravel and peat-like deposit. Radiocarbon dates suggest that the tufa formed during Subboreal, Boreal and Atlantic time. The main difference between the tufa in the Sąspowska Valley and contemporaneous tufas in other valleys of the Krakow Upland is the higher amount of non-carbonate fraction in the former. Other Lower and Middle Holocene tufas of the Krakow Upland are composed mainly or exclusively of carbonate fraction. The non-carbonate fraction in fluviatile tufas in the Sąspowska Valley resulted from erosion of loess cover in the upper part of the catchment. The erosion was related to local activity of Neolithic flint miners who cleared forest at a local scale, dug shafts in loess cover and exploited flints from underlying weathered residuum of Jurassic limestone. Consequently, they made copious amounts of loose material available for transport down the valley and subsequent trapping within the tufa depositional system.

Лесові покриви на терасах нижньої течії Свічі

The Fore-Carpathians part of Svicha River valley partially covers Morshyn and Zalissia Uplands and Stryi-Zhydachiv depression. Within the Svicha and Sukil' river valleys, there are well-developed different-age terraces with thick stratified loess covers. The investigation of the last ones can help to define nomenclature and age of the terraces. The loess covers of the third (Kolodiiv) and the fourth (Mariampil) terraces, which are represented by Pidberezhzhia and Mizhrichchia sections accordingly, are characterised in detail in the article. Pidberezhzhia section represents a sequence of alluvial and covering deposits of the third (Kolodiiv) over-floodplain terrace of Svicha River, which is developed on its right bank. The terrace is stretched out in the form of a narrow (about 2 km) strip from the village Zarichchia to the village Novoselytsia. It is separated from the Svicha riverbed by the system of different-altitude floodplain levels and the first and second over-floodplain terraces. The boundaries between them are morphologically distinct, the exceeding of the surface of the Kolodiiv terrace above the water level in the riverbed of Svicha reaches 10 m or even more. Covering loess-soil series on the terrace has a capacity of more than 6 m and begins with the Horokhiv fossil soil complex. Mizhrichchia section represents the fourth (Mariampil) over-floodplain terrace, which to the north of Mizhrichchia village forms a scarp to the riverbed of the Svicha River, about 20 m in height. The terrace on this part of the valley of the river covers small areas and it is developed between the villages of Zarichchia and Mali Didushychi. Almost along its length, the terrace directly scarps to the riverbed. On the opposite side, where the rear seam is, it borders on the fifth (Galician) over-floodplain terrace, which forms a scarp about 10 m in height. Loess cover on the fourth terrace is up to 14 m thick. There are welldeveloped Dubno fossil soil (MIS 3) and Horokhiv fossil soil complex (MIS 5) and a thick sequence of hydromorphic deposits, which obviously correspond to the Korshiv fossil soil complex (MIS 7) in loesspaleosol series. The studied Pleistocene covers allow us to reliably identify Mariampil and Kolodiiv terraces of the Svicha River, as well as outline the nomenclature of the remaining terraces of the adjacent sections of the Zalissia and Morshyn Uplands and Stryi-Zhydachiv depression. Key words: river terrace, loess-soil covers, Dubno fossil soil, Horokhiv and Korshiv fossil soil complexes, Fore-Carpathians, Zalissia and Morshyn Uplands.

Геоморфологічна будова Передкарпатської ділянки долини Бистриці-Підбузької

The geomorphological structure of one of the least explored river valleys of the north-west part of the Fore-Carpathians was discovered. Morphological, morphometric characteristics of the BystrytsiaPidbuzka terraces, the structure features of their deposits’ sections were described. The progress of the glacial morpholithogenetic processes in the north-west part of the Fore-Carpathians was detailed. It was found that the river valley has been actively developing during the Early Pleistocene epoch, when the Galician (the fifth over-floodplain) terrace and four different-age terraces, which have formed the Loyeva level (the sixth over-floodplain terrace) till now, and starosilska terrace, which is hypsographically above the Loyeva level and below the Krasna level, were formed. The benches between the bases of the multiple altitude horizons of alluvium of the identified terraces were mainly disguised by the loess cover that is why actually they were not evident in the terrain. During the Early Pleistocene epoch (the Oka stage), at the time of the deglaciation of the adjacent to the Carpathian Mountains interfluve areas of Stryvihor–Dnister and Dnister–Bystrytsia-Pidbuzka, the glacial meltwater flowed along the river valley to the south. This was illustrated by the fact of the covering of the “warm” alluvium of the channel and flood plain facies by the periglacial alluvium in the section of the Galician terrace of the Bystrytsia-Pidbuzka River. During the deglaciation process of the north-west part of the Dnister valley, the Chukva-Vilshanyk palaeovalley was also invoked. The history of its formation and the structure requires further appraisal up to now. Younger Middle-Upper Pleistocene terraces that were obviously “hidden” in the broad bottom of the river valley morphologically were not clearly demonstrated. According to the morphometric, morphological characteristics they corresponded to the first over-floodplain terrace and BystrytsiaPidbuzka floodplain. However, it has been reliably determined that only its upper 6 meters of the total 24–26-meter of the soft sediments of the mass, which was discovered in the bottom of the BystrytsiaPidbuzka River valley, have accumulated during the Holocene. The formation time of the middle and lower parts was not accurately determined so far. It is possible that it has begun to accumulate during the period of the glacial meltwater discharge, which flowed to the river valley, through both the ChukvaVilshanyk palaeovalley and the Upper-Dnister depression. The surface of the fluvioglacial deposits was covered with the Middle-Upper Pleistocene alluvium, and the section of the mentioned mass was finished by the Holocene alluvium. From the beginning of the Holocene the river valley was surrounded by the ascending tectonic movements, which were especially active on the area that is adjacent to the Carpathians, where their base was outcropped in sections the first over-floodplain terrace and the floodplain. Key words: terrace, Loyeva level, alluvium, loess, glacial meltwater, Upper-Dnister depression, Chukva-Vilshanyk palaeovalley.

Discovery of Wolitu Pb-Zn deposit through geochemical prospecting under loess cover in Inner Mongolia, China

We report the finding of the Wolitu Pb-Zn deposit in Inner Mongolia, China, through a series of geochemical surveys. The Wolitu area, located in the loess-cover area in the Hure Banner, Tongliao City, Inner Mongolia, and neighboring the Horqin Sandy Land to the north, had no previous history of Pb-Zn mining or record of Pb-Zn mineralization. Our study identified a large Pb-Zn anomaly with potential zones of mineralization by stream sediment survey. Random rock sampling reveals limonitization at sporadic outcrops in the gullies. The high concentrations of Pb in the residual debris provided guidelines to fix the position for exploratory trench. Oxidized concealed orebodies were identified by trenching. Blind orebodies in veins hosted within the structural zone between slates and marbles of the upper Carboniferous Shizuizi Formation and the Permian granite were discovered by drilling. It is computed that the ore reserve may reach up to 540,000 tones with Pb grade of 1.27% and Zn of 1.9%. This case study is an excellent example for identifying potential polymetallic deposits in loess covered terrains using geochemical exploration.

The Late Pleistocene loess-palaeosol sequence of Middle Belgium

In Belgium, two areas show extended Late Pleistocene loess cover: the Hesbaye close to Liège and the Haine Basin around Mons. For decades, correlation between both areas remained problematic. Here we will show how, by way of complementary approaches, the records of the Haine and the Hesbaye could be inserted into a high resolution pedosedimentary sequence encompassing the major part of the Late Pleistocene and reproducible at the scale of the Belgian loess belt. Based on the pedosedimentary and palaeoenvironmental signatures of the Belgian sequence, comparisons are proposed with high resolution loess sequences of Eastern Europe and Central Siberia. They give access to well documented palynological data for the first part of the Late Pleistocene and to a strong climatic record on loess framed between 45 and 10 ka BP by long series of radiocarbon dates on charcoal and wood remains. The conjunction of these complementary loess records has further given way to a consistent proxy-correlation scheme linking a high resolution continental climatic record to the Greenland ice sequence.

A new classification of earthquake-induced landslide event sizes based on seismotectonic, topographic, climatic and geologic factors

This paper reviews the classical and some particular factors contributing to earthquake-triggered landslide activity. This analysis should help predict more accurately landslide event sizes, both in terms of potential numbers and affected area. It also highlights that some occurrences, especially those very far from the hypocentre/activated fault, cannot be predicted by state-of-the-art methods. Particular attention will be paid to the effects of deep focal earthquakes in Central Asia and to other extremely distant landslide activations in other regions of the world (e.g. Saguenay earthquake 1988, Canada). The classification of seismically induced landslides and the related ‘event sizes’ is based on five main factors: ‘Intensity’, ‘Fault factor’, ‘Topographic energy’, ‘Climatic background conditions’, ‘Lithological factor’. Most of these data were extracted from papers, but topographic inputs were checked by analyzing the affected region in Google Earth. The combination and relative weight of the factors was tested through comparison with well documented events and complemented by our studies of earthquake-triggered landslides in Central Asia. The highest relative weight (6) was attributed to the ‘Fault factor’; the other factors all received a smaller relative weight (2–4). The high weight of the ‘Fault factor’ (based on the location in/outside the mountain range, the fault type and length) is strongly constrained by the importance of the Wenchuan earthquake that, for example, triggered far more landslides in 2008 than the Nepal earthquake in 2015: the main difference is that the fault activated by the Wenchuan earthquake created an extensive surface rupture within the Longmenshan Range marked by a very high topographic energy while the one activated by the Nepal earthquake ruptured the surface in the frontal part of the Himalayas where the slopes are less steep and high. Finally, the calibrated factor combination was applied to almost 100 other earthquake events for which some landslide information was available. This comparison revealed the ability of the classification to provide a reasonable estimate of the number of triggered landslides and of the size of the affected area. According to this prediction, the most severe earthquake-triggered landslide event of the last one hundred years would actually be the Wenchuan earthquake in 2008 followed by the 1950 Assam earthquake in India – considering that the dominating role of the Wenchuan earthquake data (including the availability of a complete landslide inventory) for the weighting of the factors strongly influences and may even bias this result. The strongest landslide impacts on human life in recent history were caused by the Haiyuan-Gansu earthquake in 1920 – ranked as third most severe event according to our classification: its size is due to a combination of high shaking intensity, an important ‘Fault factor’ and the extreme susceptibility of the regional loess cover to slope failure, while the surface morphology of the affected area is much smoother than the one affected by the Wenchuan 2008 or the Nepal 2015 earthquakes. The main goal of the classification of earthquake-triggered landslide events is to help improve total seismic hazard assessment over short and longer terms. Considering the general performance of the classification-prediction, it can be seen that the prediction either fits or overestimates the known/observed number of triggered landslides for a series of earthquakes, while it often underestimates the size of the affected area. For several events (especially the older ones), the overestimation of the number of landslides can be partly explained by the incompleteness of the published catalogues. The underestimation of the extension of the area, however, is real – as some particularities cannot be taken into account by such a general approach: notably, we used the same seismic intensity attenuation for all events, while attenuation laws are dependent on regional tectonic and geological conditions. In this regard, it is likely that the far-distant triggering of landslides, e.g., by the 1988 Saguenay earthquake (and the related extreme extension of affected area) is due to a very low attenuation of seismic energy within the North American plate. Far-distant triggering of landslides in Central Asia can be explained by the susceptibility of slopes covered by thick soft soils to failure under the effect of low-frequency shaking induced by distant earthquakes, especially by the deep focal earthquakes in the Pamir – Hindukush seismic region. Such deep focal and high magnitude (> > 7) earthquakes are also found in Europe, first of all in the Vrancea region (Romania). For this area as well as for the South Tien Shan we computed possible landslide event sizes related to some future earthquake scenarios.

Upper Pleistocene loess-palaeosol records from Northern France in the European context: Environmental background and dating of the Middle Palaeolithic

In Northern France the loess cover from the Last glacial (Weichselian) is represented by a semi-continuous mantle up to 8 m in thickness in the best localities such as leeward slopes (E–NE exposures). In this large area, pedostratigraphic sequences from the last Interglacial-glacial cycle (Eemian-Weichselian) have been intensively studied, especially under the auspices of active rescue archaeological programmes that have provided hundreds of individual sequences from test-pits or excavations. In spite of variations in the thickness of the different stratigraphic units, driven by differences in geomorphological contexts, the pedostratigraphic sequences from the last Interglacial-glacial cycle exhibit a particularly constant pedosedimentary pattern, including well-identified pedological and periglacial marker horizons that can be followed towards the East in Belgium, in Germany and even in Central Europe. According to the newest data, it is shown that northern France loess-palaeosol sequences are well suited to record the response of Western European environments to rapid climatic changes (Dansgaard–Oeschger cycles). The main objective of this paper is to present a summary of the pedostratigraphic sequence from Northern France, supplemented by the data from the new reference sequence of Havrincourt and a global correlation scheme with surrounding areas. In Northern France, the synthesis of the observations carried out on ca. 100 sequences during the last 20 years allows the establishment of a highly detailed pedostratigraphic and chronostratigraphic scheme that represents a unique database for the discussion of the relations between Palaeolithic occupation and environment. In this context, a strong relationship between the intensity of human occupation and the climatic and environmental context is demonstrated. This relationship appears to be conditioned by the relative abundance of large mammal fauna, itself linked to vegetation density, as indicated by the extremely sparse biomass and the hiatus in human occupation that characterise Upper Pleniglacial loess.

Кореляція терас річкових долин Волинської височини на основі морфологічних та літологічних ознак

River valleys of Volhynian Upland are characterized by a larger number of terraces and a greater depth of their downcutting compared with neighbouring Polissia and Male Polissia. We established that the major rivers of Volhynian Upland have floodplain and mostly three terraces. The valley of the Horyn River is different from others by presence of fourth terrace. According to received information, the age of forming of the highest terrace (revealed only in the Horyn Valley) can be considered as Early Pleistocene, the third terrace – Middle Pleistocene, and the two lowest terraces – Late Pleistocene. Relief of the Early and Middle Pleistocene terraces is characterized by high degree of dissection and presence of sufficiently thick loess cover. At higher Late Pleistocene terrace loess cover isn’t revealed everywhere and has a small thickness (typically up to 5 m). The lowest terrace in most valleys has local distribution and it is composed mainly of sandy material. The surface of this terrace is located on several hypsometric levels. Floodplain usually has two high-rise levels. It formed in the Holocene. Key words: river valley, terrace, floodplain, Volhynian Upland, Horyn River, Styr River, Zakhidnyi Buh River.

Comparison of volumetric and remote sensing methods (TLS) for assessing the development of a permanent forested loess gully

The gully systems develop a compact network dissecting the loess cover of the NW part of the Lublin Upland. They are overgrown by dense and multi-storey forest assemblages. It is very difficult to apply teledetection techniques, GPS positioning, and geodesic tools, such as a laser rangefinder or total station, for monitoring of gully development. The detailed research, involving the comparison of traditional and modern methods, was conducted in a gully with a secondary erosional dissection, developing in the gully bottom with varied intensity for the last 15 years. In the period of comparative research (2012/2013), the rate of development of the erosional dissection was measured by means of traditional methods as well as a Leica HDS 7000 laser scanner. 3D laser scanning permitted precise terrain modelling and the assessment of qualitative and quantitative spatial changes. This paper compares the results of three measurement campaigns. The analysis showed intensive development of the dissection, manifested in an increase in its volume (37 %), retreat of the erosion scarp (32 m), deep erosion (19 %), and lateral erosion (27 %). Registered moderate snowmelt in 2013 caused the volume dissection to increase by 57 m3, mainly as a result of the gully bottom scouring. During heavy rainfalls in June, the landforms were widened by a further 217 m3 and observed deepening and widening of erosive potholes. The prevalence of deep erosion resulted in the transformation back into a V-shaped cross section. A total of 37.3 Mg km−2 of material was discharged from the gully catchment during snowmelt runoffs in 2013. A precipitation event in June 2013 caused the discharge of 856.9 Mg km−2 of material from the catchment. The obtained results confirm that snowmelt erosion determines the spatial development of perennial gullies, but the volume of material discharged from the catchment depends on the occurrence of extreme precipitation during the warm season.

Terra Rossa catenas in Wisconsin, USA

The soils in the unglaciated part of Wisconsin have a loess cover over sedimentary rock, mostly dolostone of Ordovician age. The dolostone has weathered and produced layers of red clay or Terra Rossa. We have sampled 144 pedons of 16 catenas with different slope aspects and curvatures in a 70km2 area. Half of all the pedons had a red clay subsoil (mostly 5YR 3/4) and had on average over 40% clay. The mean thickness of the loess above the red clay was 50cm but it ranged from 7 to 130cm. The thickness of the red clay ranged from 4cm to 60cm with an average thickness of 25cm. The red clay was found in every part of the landscape except the valley bottoms: it was present in soils on summits, shoulders, backslopes, and footslopes. The red clay is only found over dolostone, but not present on all dolostone ridges. It was concluded that there is large variation in the Terra Rossa soilscapes of Wisconsin and this variation can only partly be explained by topography.

Soil and vegetation transformation in abandoned vineyards of the Tokaj Nagy-Hill, Hungary

Two chronosequences, one south (S-sequence) and one southwest (SW-sequence) with differing times since their abandonment (193, 142, 101, 63, 39 and 14years), were studied on Tokaj Nagy-Hill. The sites were investigated in respect of vegetation characteristics, soil physico-chemical characteristics, total organic carbon stocks (TOC stocks), accumulation rates of total organic carbon (TOC accumulation rates), and soil profiles, which were classified according to the World Reference Base (WRB) 2007. The S-sequence was 25–35% sloped and strongly eroded, and the SW-sequence was 17–25% sloped and moderately eroded.Vegetation development at the S-sequence resulted in shrub-grassland mosaics, supplemented by protected herb species and forest development at the earliest abandonment. The SW-sequence was predominantly covered by forest vegetation, and trees were absent at the 63 and 14year old abandonment sites.Soils of the S-sequence show shallow remnants of loess cover with redeposited soil materials containing 15–65% skeletal volcanic rock of weathering products coated by secondary calcium carbonates. The SW-sequence profiles are developed on deep loess or loess derivatives. The calcium-carbonate content was higher in profiles of the S-sequence (18.1±10.4%) than in the SW-sequence (6.7±2.7%); consequently, the pH of the topsoil was higher in the S-sequence, and correlated significantly negatively with the age of abandonment in both sequences (r=−0.893; p=0.01 in S, and r=−0.739; p=0.05 in SW). TOC stocks of the top 6cm soil layers were higher in the S slope (1.82±0.71kgm−2) than in the SW-sequence (0.95±0.49kgm−2), and correlated significantly positively with the duration of abandonment. When calculated for the whole profile, TOC stocks were similar in both S- and SW-sequences (S: 8.21±3.31kgm−2; SW: 8.24±6.01kgm−2). The TOC accumulation rates of the top 6cm soil layers exhibited 18.9±10.0g C m−2y−1 in the S and 7.0±4.2g C m−2y−1 in the SW-sequence.Sites with the same age of abandonment showed different vegetation and soil features in both chronosequences, indicating that time is not the most decisive factor in soil transformation processes after abandonment of viticulture on Tokaj Nagy-Hill. Additional directing factors were slope steepness and exposition.

Natural environment of MIS 5 and soil catena sequence along a loess slope in the Seret River valley: Evidence from the Pronyatyn Palaeolithic site (Ukraine)

The Middle Palaeolithic site in Pronyatyn village is situated on the Ternopil Plateau, on the eastern, long and straight slope of the Krucha Gora hill (369.5 m a.s.l.). The structure of loess cover in this area was investigated in the series of archaeological excavations to a depth of 5–6 m in 1977–1985, 2010 and 2011. Lithological, palaeomagnetical and palynological analyses, as well as TL dating were carried out in the selected profiles. In all profiles, under thin cover of loess from the last aeolian deposition sub-cycle (MIS 2), a set of soils of S1 = Gorohiv s.l.; (MIS 5 complex) exists. This complex is composed of interglacial and interstadial units. Forest and forest-steppe vegetation, followed by a rich steppe with the continuous occurrence of trees and shrubs and without subarctic elements, developed during the stages of its formation. Based on the investigations of loess cover carried out over a large area, it was found that all sequences are spatially diversified in the profiles located along and across the slope in the middle part of this area. This diversity resulted from the development of pedogenetic and slope processes, depending on morphological features of individual slope segments. In the southern part of the study area, outside the extent of artifact occurrence, the deposits representing MIS 5 are undisturbed or slightly disturbed and contain a loess-soil sequence, which is composed of the interglacial Cambisol (with evidence for the Blake palaeomagnetic event) and 2–3 interstadial soils. Artifacts were discovered in the northern and northwestern parts of the study area, within a solifluctionally redeposited chernozem occurring on a denuded Luvisol. Based on the analysis of the artifact collection, the flint industry is the Western-Podolian, Levallois, radial-parallel, flakes-and-blades, without two-sided tools and with domination of knife-like products on Levallois blanks. This suggestion of the flint industry age as within the younger part of MIS 5 is supported by TL dates. It is most possible that this settlement took place in MIS 5c. Based on spatial distribution of artifacts, state of their preservation, and the features of solifluction deposits representing the younger part of MIS 5, we conclude that the site was originally located on the slope above the excavation area, about 30–50 m to the west.

Digital soil mapping of a red clay subsoil covered by loess

A red clay subsoil is commonly found in the soils of the Driftless Area of Wisconsin, USA. The red clay is buried by a layer of loess and occurs on uplands underlain by dolostone. It is assumed to have derived from the impurities of the weathered dolostone. The red clay has implications for groundwater recharge and lateral flow of water through the landscape as well as the fixation of excess phosphorus from animal manure and inorganic fertilizers. Here we have produced digital soil maps at different levels of probability of the red clay presence, the depth to the red clay, and its thickness. Five hundred and sixty-one soil observations were made in a 7000ha study area and were used to investigate the relationship of the red clay to landscape characteristics and short range soil variability. Soil observations and environmental data were used to create digital soil maps using regression models and kriging. Compared to the described soil series for the study area it was found that the red clay is less red, about 10cm thinner and contains 15% less clay. At 60% probability, the model predicts 2600ha with red clay compared to 3300ha from the Soil Survey Geographic database (SSURGO), 2000ha with a 30 to 55cm loess cover (vs. 1600ha from SSURGO) and 1700ha with greater 15cm red clay thickness (vs. 3300ha from SSURGO). It is concluded that SSURGO overestimates the total area with red clay and the thickness of the clay. This study also showed how a clay subsoil can be mapped at different levels of probability.

Palaeovegetation in the Pavlovské vrchy hills region (South Moravia, Czech Republic) around 25,000 bp: the Bulhary core

This paper presents results of pollen and macroscopic analyses of a geological core from the village of Bulhary, at the north-eastern foot of the limestone Pavlovske vrchy hills, South Moravia, Czech Republic. The core reached down to about 10 m of aeolic loess layers and some 40–50 cm of compressed organogenic sediments. They accumulated around ca 25,000 years bp. The moss peat and algal gyttja we have analysed were deposited in an ox-bow of the past flood-plain of the river Dyje. The time of the sedimentation may be synchronous with the time when the northern foot of the Pavlovske vrchy hills was inhabited by upper Palaeolithic people of the Gravettian (Pavlovian) culture, dated generally to an Upper Wurmian interstadial. Archaeologists excavated their settlements in the villages of Dolni Věstonice and Pavlov, neighbouring our site of Bulhary. Our analyses permit the reconstruction of the vegetation of that time in the region but may also reveal the environment and living conditions of the Palaeolithic people. In our assemblages over 200 types of palynomorphs (pollen, spores, etc.) have been found, which indicates a very rich flora and vegetation growing in at least six different biotopes of the Pavlovske vrchy hills region: (1) Open, mostly coniferous stands with grass and herbaceous cover in their undergrowth. These were probably situated in the lowest parts of the territory and could also have dominated in the broader vicinity with loess cover. (2) Grass and herbaceous steppe-like vegetation probably occupied the belt above where the trees occurred but still within the loess zone. (3) The highest elevations of the hills and their limestone cliffs formed biotopes for a complex of subalpine (alpine) communities. (4) The flood plain was certainly occupied by very diversified tall-herb vegetation with scattered alder and willow trees or shrubs. (5) Aquatic communities of the infilled stages in the river ox-bows are well documented by microscopic and macroremain finds of water macrophytes, algae and mosses. (6) The presence of scattered spring outflows and their communities is indicated by pollen of typical spring plants, e.g. Chrysosplenium, Montia, Cardamine amara etc. The vegetation, especially that in the flood-plain, produced enough plant biomass to feed numerous herds of large herbivorous mammals, which were hunted by the Palaeolithic tribes. Also the climate was probably relatively suitable for the style of living at that time. It could have been similar to that of the present northern boreal zone of NE Scandinavia and N Russia or even milder.

XVIII українсько-польський семінар "Лесовий покрив Північного Причорномор’я”

The 18th Ukrainian-Polish seminar on “Loess cover of the Northern Black Sea region” was held on September 8–13, 2013 in the Roksolany (Odesa region).

Geotechnical design in the presence of loess cover of the Nałęczów Plateau

An analysis of the diagnosis and design solutions of road viaduct foundation in the presence of dense loess cover of the Nałęczów Plateau. The analysis was conducted with regard to the provisions and the requirements of Eurocode 7 regulations: Geotechnical design. Studies on selected physical and mechanical characteristics of soil samples taken at the time of the object foundation were performed with the use of index analysis. In the light of the tests, parameters defined very carefully were established, and the leading borderline state resulting from the very term loess and its structural sensitivity was adopted without establishing the parameter of collapse settlement (imp) or/and the value of yield stress (YSR). Design solutions of foundation resulting from the recognition, settled parameters and properties of the substrate were reconsidered to be as very careful and expensive.

Hydrogeologic and topographic controls on evolution of karst features in Illinois’ sinkhole plain

In the sinkhole plain of southwestern Illinois, the size and morphology of cover-collapse sinkholes can be used as an indicator of the size of the associated underlying crevice/conduit system. Sinkholes that lead to relatively small crevices and small conduit systems (sinkhole volumes >103 m3, but <105 m3) typically are found in areas with relatively high water tables and, based on storage capacity of conduits and secondary porosity of adjacent bedrock, are incapable of accepting large, rapidly inflowing volumes of surface-water runoff without backflooding. Once flooded, sinkholes become low-energy environments and sites of deposition of fine sediments; consequently, their growth potential (via erosion by runoff within and at the margins of the sinkhole) is limited. Conversely, in those areas where sinkholes lead to relatively large, branchwork-type cave systems, water tables are typically deeper and the storage capacities of the cave system and adjacent bedrock can be one or more orders of magnitude greater. Because these large cave systems can accept greater volumes of rapidly inflowing runoff without backflooding, the sinkholes associated with large cave systems typically become sites of extensive erosion. The aerial extent of a sinkhole draining to large cave systems may continue to increase and incorporate other sinkholes within its drainage area, thereby creating large, compound sinkholes up to 30 ha in area. These sinkholes can have direct or indirect connections to cave passages and have volumes that can be as small as 104 m3 and as large as 106 m3. Beneath the glacial till and loess cover, and in the vicinity of the largest cover-collapse sinkholes, irregularities in bedrock topography appear to have had an effect on the location of the initiation of large caves in the sinkhole plain. The coincidence of bedrock depressions and swales in close proximity to the initiation point of the large caves suggests that focused recharge to fractures leading to bedding-plane partings in bedrock played a major role in the initiation and evolution of the large branchwork-type caves of Illinois’ sinkhole plain.