Boulder Clay Research Articles

Evidence of brines interconnections and different flow patterns within the boulder clay glacier and its moraine (Victoria Land, East Antarctica).

Multi-technique integrated surveys were carried out to investigate brine characteristics, connectivity and flow patterns in the Boulder Clay Glacier area, Victoria Land, East Antarctica. Specifically, electromagnetic geophysical surveys focused mainly on Ground Penetrating Radar (GPR) and integrated by Frequency Domain induction, not only demonstrated the presence of brines in the subsurface, but also allowed to image several structures and glaciological elements. Chemical analyses suggested the origin and differentiation of the brines, providing evidence for interconnected pathways. To the best of our knowledge, this is the first time that brines interconnection and their chemical common footprint is demonstrated below a glacier and its moraine at shallow depth, combining boreholes, geophysical, geomorphological, and chemical data. This demonstrates that liquid flows can occur at very shallow depths, even in continental Antarctica, and that pressurised brines can flow beneath and through glaciers and moraines.

Integrated geophysical and geospatial techniques for surface and groundwater modeling

An integrated approach using geophysical and geospatial techniques was employed to model the surface and subsurface water-bearing strata and assess aquifer vulnerability in the Sehnsa town, Kotli district, State of Azad Kashmir, Pakistan. The inadequate scientific studies in the hilly terrain with such complex geological conditions has led to the failure of the boreholes for groundwater extraction. For the evaluation of groundwater potential and subsurface lithology, 30 vertical electrical soundings (VES) stations utilizing the Schlumberger electrode configuration were completed, modeled and analyzed spatially. Numerous geoelectrical parameters like true resistivity, thickness of subsurface layers and Dar-Zarrouk parameters were evaluated. The subsurface lithology delineated comprised topsoil, clayey sand, sandstone, and boulder clays which closely resemble to the borehole lithologs available in the study area. The inversion model confirms the presence of patches of high-resistivity sandstone in the southwestern part of the study area with the maximum thickness of the aquifer up to 140 m. Most aquifers were classified as unconfined with Q–type resistivity curves. The protective overburden capacity of the aquifers is rated as poor at VES 1, 3–5, 8, 10–16, 18, 19, 22–25, 27 and 30 whereas the moderate category was found at VES 2, 9 and 20 and excellent at VES 7 and 28, respectively. Therefore, the VES stations with poor and moderate ratings of overburden protective capacity are vulnerable for surface contaminants. The aquifer recharge was associated with rainfall and partly from the Poonch River. The effective integration of geophysical and geospatial techniques in this study provides sufficient information about the regional water resources and gives a preliminary model that can facilitate efficient water resource management in the area. These approaches can be successfully applied to diverse geographical and hydrogeological sites due to their versatility and reliability.

A climate change from icehouse to greenhouse following Huronian glaciation: Evidence from long-term storm deposits of the Paleoproterozoic Hutuo Group in the North China Craton

The Hutuo Group was deposited from 2.14 to 2.0 Ga in Wutai Mountain, North China Craton. This group is composed of the Doucun and Dongye subgroups, which are likely contemporaneous heterotopic facies. The Hutuo Group displays well-known positive to negative drifts of inorganic carbon isotopes, large-scale stromatolitic carbonates, and red beds in epigenetic environments. Twelve storm-deposited lithofacies were identified in the Dongye Subgroup, which changes from sandstones, siltstones, and mudstones of the Qingshicun and lower Wenshan formations to carbonates of the upper Wenshan, Hebiancun, Jian’ancun, Daguanshan, Huaiyincun, Beidaxing, and Tianpengnao formations from bottom to top. The above sedimentary sequence transformation indicates a gradual transformation from terrigenous storm deposits in the Qingshicun and Wenshan formations to endogenous or mixed-source storm deposits in the Hebiancun, Jian’ancun, Daguanshan, and Huaiyincun formations. Additionally, coastal and shallow-marine storm deposits are revealed from sedimentary structures, including hummocky cross-stratification, intraclasts or boulder clays exhibiting radial or chrysanthemum-shaped stacking, and sinuous or torn stromatolites. These storm deposits, occurring with oolitic and stromatolitic carbonates of mid-low latitudes or tropical-subtropical zones, are characterized as tropical storm deposits. Based on reported ages, we propose that such tropical storms started from ca. 2.1 Ga and lasted for over 40 Myr. The long-term storm deposits indicate high temperatures and intense water circulation during the greenhouse climate. A climate change from icehouse to greenhouse is also evident by the extensive distribution of carbonates, evaporates, and organic-rich shales above the glacial diamictites in multi-cratons, and was probably driven by the transformative evolution of the atmosphere.

The 1st Hanrahan Lecture: Geotechnical properties of Irish glacial and interglacial soils

This paper reviews the current state of the art in relation to geotechnical design in unsorted till deposits, commonly called boulder clays by engineers or diamictons by geologists, generally taking the topics discussed by Professor Eamon Hanrahan in his seminal work of 1977 on Irish tills. These topics include the permeability, stiffness and consolidation characteristics of these deposits, together with their undrained and drained behaviour. The geological background to the deposition of these tills is discussed and the available information on the presence of interglacial soils around the country is presented. Where possible, practical experience from working with these deposits is compared with predictions made from field or laboratory test results: for example, in settlement assessment of foundations, slope stability and in earthworks. Whilst most of Ireland is covered with stony boulder clays, which is the main topic of this paper, the geotechnical parameters of a fine-grained till encountered on the east coast, known as Irish Sea Till or colloquially as Macamore Clay, are discussed and the implications of this on slope stability is investigated.

Record of aeolian processes in Pleistocene deposits in the foreland of the European sand belt

Abstract This article presents the degree of aeolization of Pleistocene deposits in the foreground of the European sand belt in southern Poland. Ten of the 13 sites were established in the Oświęcim Basin and three in the south part of the Silesian Upland. Attention was focused on four types of deposits formed during three glaciations (Sanian, Odranian, Vistulian): boulder clay, fluvioglacial sands and gravels, end moraine deposits, and aeolian sands. Quartz grain abrasion (for the 0.8–1.0 mm fraction) was examined by mechanical graniformametry and the morphoscopic method. The record of aeolian processes in analyzed deposits is the presence of quartz grains RM (very well-rounded and mat) and EM/RM (moderately rounded and mat). They were found in deposits of various origins and ages but in variable proportions. Considering only the average percentage of grains RM, it should be regarded that abrasion of deposits is low in the case of fluvioglacial deposits, moderate in the case of glacial deposits, and good in the case of aeolian deposits. However, the key factor in determining the degree of abrasion is the share of EM/RM grains, which in the abovementioned deposits are seven, three, and twice as many as RM grains. Therefore, the most noteworthy research result is the very high total share of grains with aeolian abrasion (RM + EM/RM), amounting on average to 84.1% for Odranian fluvioglacial deposits, 86.7% for Sanian glacial deposits and 92.6% for Late Glacial aeolian deposits. It means that in the study area, glacial and fluvioglacial transport included deposits with good aeolian abrasion obtained in the periglacial environment before the transgression of the ice sheets. Probably due to the longer persistence of periglacial conditions in southern Poland, compared to its central and northern parts, the degree of aeolization of fluvioglacial and glacial deposits is better. At the same time, there is a significant differentiation in the aeolization of fluvioglacial deposits within the outwash plain in the foreland of the maximum extent of the Odranian ice sheet. In its proximal part, near the front of the ice sheet, fluvioglacial deposits are characterized by much worse abrasion of quartz grains than in the distal part.

BED PROTECTION FOR EXTREME STORM SURGE INFLOW THROUGH FAILING SLUICEGATES

At the northern part of The Netherlands the closure dam Afsluitdijk is situated. It is the primary flood defense that closes off Lake IJssel from the Wadden Sea to protect the northern provinces against storm surges. This structure was built in the 1930’s and needed to be improved to withstand the foreseen increase in storm surge conditions and sea level rise. It consists of a 32 km long dam with five discharge sluices for regulating the water level at Lake IJssel. Three of these sluices are located in the west end of the dam and two in the east end. Due to climate change larger discharges are foreseen. Therefore two new sluices were built in between the three old sluices at Den Oever in the west end of the dam to increase the capacity. A new bed protection was designed at Lake IJssel to ensure the stability of the old and new sluices. This bed protection needs to withstand the inflow during the worst case scenario that one sluice does not close during a 45 hour storm surge. This event has a probability of occurrence of 1/1,000,000 per year. During this extreme load case, water flows from the Wadden Sea through the open sluice gates into Lake IJssel. The water level difference is up to 6.6 m. This causes discharges up to 3600 m3/s and currents that are supercritical with speeds up to 9 m/s. Erosion of the bed cannot be prevented entirely with these high velocities. The length of the bed protection is designed large enough to keep the scour hole away from the sluices. The bed protection consists of a structural and a natural part. The natural part was introduced to minimize the length of the structural protection, reducing the construction costs and CO2 footprint. For this design approach the erosion resistant boulder clay layers in the subsoil were taken into account as natural bed protection, ‘Building with Nature’. To achieve the custom made design was a challenge. To predict the flow behavior in combination with the erosion process was extremely complex. This could not be predicted with the conventional formulas and methods. Therefore multiple approaches were used and combined. This resulted in the design being based on the combination of computer simulations, 2D and 3D model tests and calculations with conventional formulas. The structural part of the bed protection has a length of 24 m. The first 19 m is a concrete slab with a sheet pile at the end. The last 5 m consists of grouted rock. The thickness of the concrete slab and grouted rock is 1-1.5 m. This large thickness is required to prevent uplift due to the supercritical flow. Further downstream of this structural bed protection a scour hole will develop. At this location the boulder clay forms the natural part of the bed protection. The expected development of the flow field and geometry of the scour hole during the 45 hour storm surge was determined. The scour resistance of the boulder clay was based on laboratory tests with samples taken on site. This lead to the conclusion that the boulder clay reduces the development of the scour hole enough to ensure the stability of the structural part of the bed protection and the stability of the sluices.

The Theoretical Potential of Hondsrug Glacial Rock Dust as Soil Remediator in The Netherlands

Agriculture in the Netherlands is a major source of ammonia (NH3) emissions. Deposited nitrogen levels in the Netherlands reached 2-3 times their critical value at the start of 2020. Excess nitrogen in soil may cause declines in biodiversity and ecosystemic disequilibrium. This may lead to acidic and decalcified soils that are less capable of retaining nutrients. The mineral fines in rock dust are proven agents in soil remediation and remineralization. Glacial moraine deposits are a branded source of rock dust and are contained in the glacial till of the “Hondsrug” area, a boulder clay ridge in the northeastern Netherlands. Formerly, erratic rocks from this boulder clay served various practical purposes. The existing apparent inutility of these erratic rocks motivates us to review their potential as rock dust. Lack of chemical analyses on the in situ erratic rocks resorts to an evaluation of their inferred Fennoscandian source rocks which are of igneous and sedimentary lithology. The chemical composition of these inferred source rocks is compared with that of proven rock dust suppliers. It is concluded that even though there are compositional parallels between the rock dust, the Hondsrug area glacial till is comparatively decalcified and mineralogically of limited benefit. Moreover, exceptional magnitudes of erratic rocks are scarcely encountered while at the same time, the bulk is preserved as geological heritage. Despite the adversities, it could be chosen to commence trials with crushing idle erratic rocks in the Hondsrug area whenever this may be assessed as a useful supplement.

Antarctic Salt-Cones: An Oasis of Microbial Life? The Example of Boulder Clay Glacier (Northern Victoria Land).

The evaporation of a localized, highly saline water body of the Boulder Clay debris-covered glacier, in the Northern Victoria Land, probably generated the accumulation of mirabilite (Na2SO4 × 10H2O) and thenardite (Na2SO4) in a glacier salt-cone. Such an extremely cold and salty environment resembles the conditions on Mars, so it can be considered a terrestrial analog. The study was aimed at gaining a first glimpse at the prokaryotic community associated with Antarctic mirabilite and thenardite minerals and also to find clues about the origin of the salts. For this purpose, samples were analyzed by a next generation approach to investigate the prokaryotic (Bacteria and Archaea) diversity. Phylogenetic analysis allowed the identification of Bacteroidota, Actinobacteriota, Firmicutes, and Gammaproteobacteria as the main bacterial lineages, in addition to Archaea in the phylum Halobacterota. The genera Arthrobacter, Rhodoglobus, Gillisia, Marinobacter and Psychrobacter were particularly abundant. Interestingly, several bacterial and archaeal sequences were related to halotolerant and halophilic genera, previously reported in a variety of marine environments and saline habitats, also in Antarctica. The analyzed salt community also included members that are believed to play a major role in the sulfur cycle.

The control of Pleistocene palaeogeography on the distribution of sandy patches in a silty Holocene lagoon (central Netherlands)

The brackish lagoon in the central part of The Netherlands was closed by a dike in 1932 and gradually changed into a lake. Parts of this lake were reclaimed and the surficial sediments of one of the polders (Noordoostpolder), reclaimed in 1942, has been investigated in detail by mapping of the walls of some 1500 km of drainage ditches approx. 1.4 m deep. It appeared that the sediments consist of an uncommonly large amount of silt, to different degrees mixed with reworked peat that had developed during the Holocene transgression. Some sandy deposits occur locally, at places that are at first sight distributed in a haphazard way. The various sandy patches have different characteristics (grain-size distribution, rounding of the grains, mineral composition). These sands cannot have been introduced from the sea, nor can they have been supplied by the rivers that discharged into the lagoon, so they must have a local origin. It is found that several types of Pleistocene sandy or diamictic deposits below the Holocene peat and lagoonal sediments had an irregular topography and became eroded during the Holocene by wave activity. This resulted in sandy deposits around these Pleistocene highs, which consisted of glacial tills (boulder clays), river dunes (formed by aeolian activity along rivers under dry permafrost conditions) and coversand ridges, formed by aeolian activity in a belt between the ice margin and the more distal loess belt. This finding implies that palaegeographical interpretations of local grain-size anomalies in a specific deposit should not only consider facies changes due to changes in the sediment supply, but should also consider local erosion leading to the exposure of previously deposited material with a divergent composition.

Comprehensive Solutions for Glasgow Boulder Clay with a New Version of Pressuremeter

Comprehensive Solutions for Glasgow Boulder Clay with a New Version of Pressuremeter

A Comparison Between Schlumberger and Wenner Configurations in Delineating Subsurface Water Bearing Zones: A Case Study of Rawalakot Azad Jammu and Kashmir, Pakistan

The Schlumberger and Wenner Electrical Resistivity Survey techniques have been used in comparison for the determination of groundwater potential in District Rawalakot, Azad Jammu and Kashmir. The terameter SAS4000 with accessories was used for data acquisition. The data were processed by employing IPI2WIN software to determine the depth, thickness and true resistivity of the subsurface layers. The present study indicated the subsurface depth coverage of Schlumberger configuration is greater than Wenner configuration. The apparent resistivity maps using both Wenner and Schlumberger techniques at the same locations have been prepared at 3m, 4m, 9m, 10m, 27m, 30m, 50m, 51m, 100m, and 150m depths respectively for groundwater assessment. The differences in resistivity contour closures, in both types of maps, arise due to lateral variations of subsurface lithology. Longitudinal conductance, transverse resistance and anisotropic maps were also prepared. The different contour closures in the Wenner map were due to mixed lithology of alluvium with variable water contents. The subsurface geology i.e. clay, sandstone boulder clay, and dry sandy soil were interpreted which are in close agreement with the surface geology of the area. The aquifers of the project area are designated as confined and unconfined good water potential indicated by low values of resistivity. The water-bearing strata consist of sand, gravel, boulder clay and sandy clay.

Origin and technology of the Georgian brick at Fade Mansion, Dublin, built c. 1728

This paper studies the provenance and firing technology of the Fade Mansion brick. The microstructure was studied with scanning electron microscopy (SEM), mineral associations and transformation were determined with X-ray diffraction (XRD) and petrographic analyses. The results evidenced that the bricks were made with a decalcified, silica-based clay of glacio-fluvial origin, gathered locally. This agrees with the position of the Mansion on a terrace of the River Liffey, and with previous research on historic bricks made with boulder clay. They were fired in kilns in an oxidising atmosphere. The rubbers at window heads reached lower temperatures which resulted in low vitrification, leading to weathering. Initial vitrification structures generally concur with the occurrence of clay minerals, indicating temperatures of c. 800°C. Continuous vitrification is associated to the disappearance of clay minerals, the sintering of hematite and/or high-temperature phases and mica transformation, indicating a wide temperature range >950-1200°C, which agrees with the inconsistent brick properties.

First Insights into the Microbiology of Three Antarctic Briny Systems of the Northern Victoria Land

Different polar environments (lakes and glaciers), also in Antarctica, encapsulate brine pools characterized by a unique combination of extreme conditions, mainly in terms of high salinity and low temperature. Since 2014, we have been focusing our attention on the microbiology of brine pockets from three lakes in the Northern Victoria Land (NVL), lying in the Tarn Flat (TF) and Boulder Clay (BC) areas. The microbial communities have been analyzed for community structure by next generation sequencing, extracellular enzyme activities, metabolic potentials, and microbial abundances. In this study, we aim at reconsidering all available data to analyze the influence exerted by environmental parameters on the community composition and activities. Additionally, the prediction of metabolic functions was attempted by the phylogenetic investigation of communities by reconstruction of unobserved states (PICRUSt2) tool, highlighting that prokaryotic communities were presumably involved in methane metabolism, aromatic compound biodegradation, and organic compound (proteins, polysaccharides, and phosphates) decomposition. The analyzed cryoenvironments were different in terms of prokaryotic diversity, abundance, and retrieved metabolic pathways. By the analysis of DNA sequences, common operational taxonomic units ranged from 2.2% to 22.0%. The bacterial community was dominated by Bacteroidetes. In both BC and TF brines, sequences of the most thermally tolerant and methanogenic Archaea were detected, some of them related to hyperthermophiles.

A Comparison Between Schlumberger and Wenner Configurations in Delineating Subsurface Water Bearing Zones: A Case Study of Rawalakot Azad Jammu and Kashmir, Pakistan

The Schlumberger and Wenner Electrical Resistivity Survey techniques have been used in comparison for the determination of groundwater potential in District Rawalakot, Azad Jammu and Kashmir. The terameter SAS4000 with accessories was used for data acquisition. The data were processed by employing IPI2WIN software to determine the depth, thickness and true resistivity of the subsurface layers. The present study indicated the subsurface depth coverage of Schlumberger configuration is greater than Wenner configuration. The apparent resistivity maps using both Wenner and Schlumberger techniques at the same locations have been prepared at 3m, 4m, 9m, 10m, 27m, 30m, 50m, 51m, 100m, and 150m depths respectively for groundwater assessment. The differences in resistivity contour closures, in both types of maps, arise due to lateral variations of subsurface lithology. Longitudinal conductance, transverse resistance and anisotropic maps were also prepared. The different contour closures in the Wenner map were due to mixed lithology of alluvium with variable water contents. The subsurface geology i.e. clay, sandstone boulder clay, and dry sandy soil were interpreted which are in close agreement with the surface geology of the area. The aquifers of the project area are designated as confined and unconfined good water potential indicated by low values of resistivity. The water-bearing strata consist of sand, gravel, boulder clay and sandy clay.

The prokaryotic community in an extreme Antarctic environment: the brines of Boulder Clay lakes (Northern Victoria Land)

During summer 2014, three hypersaline brines were discovered in two frozen lakes of Boulder Clay (Northern Victoria Valley, Antarctica). Ongoing research seeks to gain novel insights on the microbial ecology of such environments, in order to further the understanding of life adaptation to extreme conditions. To this aim, the abundance of prokaryotic cells (including cell morphologies and size for biomass conversion), the amount of viable cells (in terms of membrane-intact cells and respiring cells), the viral count, the physiological profiles at community level and the main microbial enzymatic activities were described. The brines differed each other in terms of prokaryotic cells’ abundance, size, and viability as well as viral abundance. Cell morphotypes and metabolic responses also varied among the brine samples. Underground interconnections were likely to occur, with the microbial community becoming more abundant and structured to better exploit the limited resource availability. Overall, complex interactions among multiple environmental factors, including marine water origin, depth horizon, isolation time of the brines, and climatic variations, reflected on the microbial community distribution patterns and highlighted the need to preserve these niches of extreme life.

Prokaryotic Diversity and Metabolically Active Communities in Brines from Two Perennially Ice-Covered Antarctic Lakes.

The genomic diversity of bacteria and archaea in brines (BC1, BC2, and BC3) from two adjacent and perennially frozen Antarctic lakes (L16 and L-2) in the Boulder Clay (BC) area was investigated together with the metabolically active fraction of both communities, by analyzing the bulk rRNA as a general marker of metabolic activity. Although similar bacterial and archaeal assemblages were observed at phylum level, differences were encountered when considering the distribution in species. Overall, the total bacterial communities were dominated by Bacteroidetes. A massive occurrence of flavobacterial sequences was observed within the metabolically active bacterial communities of the BC1 brine, whereas the active fractions in BC2 and BC3 strongly differed from the bulk communities being dominated by Betaproteobacteria (mainly Hydrogenophaga members). The BC lakes also hosted sequences of the most thermally tolerant archaea, also related to well-known hyperthermophiles. Interestingly, RNA sequences of the hyperthermophilic genus Ferroglobus were retrieved in all brine samples. Finally, a high abundance of the strictly anaerobic methanogens (such as Methanosarcina members) within the active community suggests that anoxic conditions might occur in the lake brines. Our findings indicate perennially ice-covered Antarctic lakes as plausible terrestrial candidates for the study of the potential for extant life on different bodies of our solar system.

The Spatio-Temporal Variability of Frost Blisters in a Perennial Frozen Lake along the Antarctic Coast as Indicator of the Groundwater Supply

Remote sensing, and unmanned aerial vehicles (UAVs) in particular, can be a valid tool for assessing the dynamics of cryotic features as frost blisters and to monitor the surface changes and the sublimation rates on perennially frozen lakes that host important ecosystems. In this paper, through the use of these remote sensing techniques, we aim to understand the type of groundwater supply of an Antarctic perennial frozen lake that encompasses two frost blisters (M1 and M2) through the temporal analysis of the features’ elevation changes (frost blisters and lake ice level). The frozen lake is located at Boulder Clay (northern Victoria Land, Antarctica). We relied on several photogrammetric models, past satellite images and ground pictures to conduct differencing of digital elevation models, areal variations and pixel counting. In addition, in situ measurements of the ice sublimation or snow accumulation were carried out. The two frost blisters showed different elevation trends with M1 higher in the past (1996–2004) than recently (2014–2019), while M2 showed an opposite trend, similarly to the ice level. Indeed, the linear regression between M2 elevation changes and the ice level variation was statistically significant, as well as with the annual thawing degree days, while M1 did not show significant results. From these results we can infer that the groundwater supply of M1 can be related to a sublake open talik (hydraulic system) as confirmed also by pressurized brines found below M1, during a drilling in summer 2019. For M2 the groundwater flow is still not completely clear although the hydrostatic system seems the easiest explanation as well as for the uplift of the lake ice.

A Pilot Project to Limit the Human Impacts on the Fragile Antarctic Biota: Mitigation of a Runway through Vegetation Transplantation

Background: Antarctica is among the world’s last great wildernesses, but the anthropogenic activities and associated infrastructures threaten its fragile biota. We quantify the impact of the construction of a 2200 m long gravel runway airstrip for airfreight operations of the Italian research station on vegetation ecosystems at Boulder Clay (continental Antarctica). We propose a pilot project to mitigate this impact through the transplantation of vegetation from the runway to safe sites. Methods: A vegetation field survey was performed through phytosociological relevés and vegetation mapping and data were analyzed through multivariate analysis. Results: We quantify the destructive impact of the runway construction on the flora and vegetation of Boulder Clay. Based on vegetation characteristics, 28 priority areas were transplanted from the runway to safe sites, with 89% of survival. Conclusions: To our knowledge, this is the first time that vegetation transplantation was performed in Antarctica to mitigate the consequences of human actions, as formerly it was used only for scientific experiments. This pilot project provides a tool to support management decisions, involving the quantitative evaluation of the infrastructure impacts and showing the suitability of practical mitigation actions. This pilot project proposes a practical tool exportable to all Antarctica and beyond and suggests to link the permissions’ release for the new infrastructures in Antarctica to the realization of specific conservation and mitigation actions.

Intra- and inter-cores fungal diversity suggests interconnection of different habitats in an Antarctic frozen lake (Boulder Clay, Northern Victoria Land).

A perennially frozen lake at Boulder Clay site (Victoria Land, Antarctica), characterized by the presence of frost mounds, have been selected as an in situ model for ecological studies. Different samples of permafrost, glacier ice and brines have been studied as a unique habitat system. An additional sample of brines (collected in another frozen lake close to the previous one) was also considered. Alpha- and beta-diversity of fungal communities showed both intra- and inter-cores significant (p < 0.05) differences, which suggest the presence of interconnection among the habitats. Therefore, the layers of frost mound and the deep glacier could be interconnected while the brines could probably be considered as an open habitat system not interconnected with each other. Moreover, the absence of similarity between the lake ice and the underlying permafrost suggested that the lake is perennially frozen based. The predominance of positive significant (p < 0.05) co-occurrences among some fungal taxa allowed to postulate the existence of an ecological equilibrium in the habitats systems. The positive significant (p < 0.05) correlation between salt concentration, total organic carbon and pH, and some fungal taxa suggests that a few abiotic parameters could drive fungal diversity inside these ecological niches.

Changes in Late Funnel Beaker Pottery at the End of the 4th Millennium BC on the Polish Lowland: Case of Mrowino, Site 3. Preliminary Report on Mineralogical and Petrographic Research

Abstract Archaeological site no. 3 at Mrowino is located on the Polish Lowland, in the Greater Poland region. It was excavated from 1973 until 1980. The excavation produced very rich movable finds, with the core of them being formed by Funnel Beaker culture (FBC) ceramics. The collections hold over 37,500 FBC pottery shards and several intact or reconstructed vessels. The vast majority of pottery comes from an FBC settlement dated to 3300-3150 BC. The pottery set includes vessels of clear Baden culture connections. For the mineral-ogical and petrographic study, 40 samples were selected to identify mineral and rock components of the ceramic body and compare the ways of raw-material preparation. In the studied samples, boulder clay in all probability was used to make the vessels. All studied samples were made from clay with grog and a small amount of sand as temper. In addition, several samples contained igneous rock crumbs. To find out if this was a deliberate or accidental admixture, it is necessary to carry out further research.