Clay mineralogy fingerprinting of loess-mantled soils on different underlying substrates in the south-western Poland

Loess may be integrated into slope deposits at different soil depths and may influence related physical, chemical and mineralogical soil properties. Therefore, tracking the border between deposited loess and underlying materials and estimating the depth of loess penetration is a challenge. Five soils from the Lower Silesia province in south-western Poland having different types of geologic substrate and being covered by loess deposits of various thicknesses were chosen to: 1) trace the origin of phyllosilicates in these heterogeneous soils (loess vs. underlying bedrock); 2) determine the influence of the geologic substrate and the loess mantle on clay mineral transformation in the soil; and 3) relate clay mineralogical traits to soil morphology. The loess consisted of long-distance and local aeolian sources as shown by the Ti/Zr ratios and heavy mineral composition. Geochemical and mineralogical traces of loess were easily detected in the mixed zone and in part also in the basal layer. The loess deposits are characterised by mica, chlorite, kaolinite, interstratified mica-vermiculite or hydroxy-interlayered vermiculite, vermiculite and a minor amount of smectite. Aeolian silt admixture was an important source of chlorite at all sites. The vertical distribution of mica indicated two types of sources — loess input and substrate. Smectite, however, has mostly been inherited from the underlying bedrock (serpentinite, glacio-fluvial deposits and basalt slope sediment) or was formed in the soils from mica or chlorite. Where present in the loess, smectite was only found in small amounts. The presence of kaolinite, HIV and mixed layered mica-vermiculite could be derived either from aeolian input or neoformation and thus actively occurring mineral (trans)formation reactions. Similar to mica, vermiculite was derived from both aeolian input and the geological substrate. The widespread loess deposits in this region rejuvenated the soil formation process, as evidenced by their mineralogical and chemical composition

Chronostratigraphy of silt-dominated Pleistocene periglacial slope deposits on Mt. Ślęża (SW, Poland): Palaeoenvironmental and pedogenic significance

Slope deposits with aeolian silt admixture are a widespread parent material of soils in the temperate zone but may be neglected when rates of soil production are quantified. The concept of periglacial cover beds differentiates slope deposits with or without aeolian silt admixture; yet there is a remaining debate on processes and the timing of their formation. A previous study done by us at Mt. Ślęża, SW Poland, concluded that slope deposits with variable aeolian silt admixture, or its lack, have a significant influence on the pathway of soil formation. The present work builds upon this finding, by adding further granulometric and micromorphological data from three representative profiles along a toposequence, in order to refine our understanding of local slope deposits and soil formation. Additionally, seven numerical ages using luminescence dating provide a chronological framework for our reconstructions and allow linking the forming processes of these pedosedimentary records to regional palaeoenvironmental conditions. The oldest aeolian deposits are of Middle Pleistocene age (>280 ± 19 ka) with interlayered palaeosol (marine isotope stage [MIS] 9 or older). Late Pleistocene slope deposits encompass the maximum loess thickness and are dated to MIS 2. Luminescence ages from the upper layers indicate shallow reworking, which we tentatively correlate to the Younger Dryas (YD). Two profiles with thick loess mantles have strong clay illuviation features, presumably formed during the Holocene. However, weak clay illuviation in the third profile with a thin loess mantle (having an age of YD) over granite regolith seems to have occurred before the Holocene, as only fragmented clay coatings (probably MIS 2 pedogenesis) could be found. © 2020 The Author

Mass fluxes and clay mineral formation in soils developed on slope deposits of the Kowarski Grzbiet (Karkonosze Mountains, Czech Republic/Poland)

Weathering, mineral formation, and transformation processes along slopes are complex. In cool mountainous regions, undisturbed soil development with a strong vertical leaching element may abruptly change as a result of erosion, accumulation, lateral water fluxes and aeolian input. We investigated soils in the eastern Karkonosze Mountains that have developed on silicatic slope deposits. To date, illite, vermiculite and chlorite are the minerals that have been detected in the clay fraction. Although the climate and parent material should be favourable for the formation of smectites, expandable phases were not verified so far. We investigated if expandable phases could be detected and how they related to elemental fluxes along a short slope sequence (1142–1268 m a.s.l. on the border between the Czech Republic and Poland). Mass balance calculations indicated intensive mineral weathering together with a significant leaching of Mg, Al, Ca and Mn on the shoulder and foot slope positions. In the middle zone, which has a concave or undulating surface shape, however, the mass balances of several elements (Na, K, Al, P) revealed a less pronounced leaching (corresponding to a lower degree of podsolization) and in some cases even accumulation. At all sites, mass balance calculations and detected soil minerals (e.g. the increase in illite towards the surface together with an increase in Al and K) indicate some aeolian input. Kaolinite was detected in all soil horizons. Its concentration slightly increased towards the soil surface. Together with the pronounced leaching of Ca, part of kaolinite originates from plagioclase weathering. Besides being a weathering product of primary minerals, part of the kaolinite is inherited from the parent material and probably is also due to aeolian input. In all soils, illite was being transformed into vermiculite and smectites (through regularly-interstratified illite-smectite phases). In addition, the content of chloritic components which increases with depth indicated their concurrent weathering and transformation into smectites. Amphibole also may have acted as a source of smectites. Not all smectite is being actively formed in the soil. Most likely due to slope processes (cover beds) that affected even the subsoil, some smectite has been transferred along the slope. Part of the smectite also seems to derive from the parent material. Active formation of expandable clay minerals is related to convex and planar landscape forms. This relationship suggests intense element leaching, inheritance from the parent material and cover bed mixing processes have contributed to the presence of smectite. Along the slope, zones with predominant vertical transport (shoulder, foot slopes) may repeatedly be interchanged with zones dominated by lateral transport (undulating slope, concave forms)

Provenance and paleoenvironmental context of the Late Pleistocene thin aeolian silt mantles in southwestern Poland – A widespread parent material for soils

Thin loess deposits are widespread soil parent materials and important archives for paleoenvironmental reconstruction. The origin of loess in SW Poland is attributed to the Great Odra Valley (GOV), following the general concept that large rivers play a major role in regional silt supply. Yet, the precise provenance (glacier sources and/or local rocks) of silts, possibly deflated from dry GOV braided riverbeds, is not clear. Our study of thin and thick loess mantles in SW Poland for the first time indicates the provenance of thin loess based on mineralogical (MLA-SEM) and isotopic analyses (143Nd/144Nd, 87Sr/86Sr). Luminescence ages of five localities point to thin loess mantle formation during and shortly (23.0 to 17.7 ka yr) after the Last Glacial Maximum (LGM). Our isotopic data indicate that thin loess deposits in SW Poland are the mixtures of two main components – local Sudetic and Scandinavian, the latter delivered by the Fennoscandian ice sheet (FIS). Also, detailed analyses of heavy minerals show that a single mineral (e.g., hornblende) may come from both Sudetic and Scandinavian sources. This research highlights the role of the (Pleistocene) GOV in collecting and homogenizing materials, while supplying the region with fine particles to be deflated by paleowinds from open surfaces. Anomalies in mineralogy and isotopic composition are connected with influence of Sudetic mountain rivers and locally blowing silt material by katabatic winds. Regional grain size differentiation of thin loess mantles explains transport distance and altitude. © 2021 The Author

Chronostratigraphy of silt-dominated Pleistocene periglacial slope deposits on Mt. Ślęża (SW, Poland): Palaeoenvironmental and pedogenic significance

Slope deposits with aeolian silt admixture are a widespread parent material of soils in the temperate zone but may be neglected when rates of soil production are quantified. The concept of periglacial cover beds differentiates slope deposits with or without aeolian silt admixture; yet there is a remaining debate on processes and the timing of their formation. A previous study done by us at Mt. Ślęża, SW Poland, concluded that slope deposits with variable aeolian silt admixture, or its lack, have a significant influence on the pathway of soil formation. The present work builds upon this finding, by adding further granulometric and micromorphological data from three representative profiles along a toposequence, in order to refine our understanding of local slope deposits and soil formation. Additionally, seven numerical ages using luminescence dating provide a chronological framework for our reconstructions and allow linking the forming processes of these pedosedimentary records to regional palaeoenvironmental conditions. The oldest aeolian deposits are of Middle Pleistocene age (>280 ± 19 ka) with interlayered palaeosol (marine isotope stage [MIS] 9 or older). Late Pleistocene slope deposits encompass the maximum loess thickness and are dated to MIS 2. Luminescence ages from the upper layers indicate shallow reworking, which we tentatively correlate to the Younger Dryas (YD). Two profiles with thick loess mantles have strong clay illuviation features, presumably formed during the Holocene. However, weak clay illuviation in the third profile with a thin loess mantle (having an age of YD) over granite regolith seems to have occurred before the Holocene, as only fragmented clay coatings (probably MIS 2 pedogenesis) could be found

Holocene vegetation history and soil development reflected in the lake sediments of the Karkonosze Mountains (Poland)

A 11-m-long lake sediment core of a mountain lake situated at 1225 m a.s.l. in the Karkonosze Mountains (Poland) provided a unique, multi-proxy archive to reconstruct natural and human-induced environmental changes over the entire Holocene period. Pollen analyses allowed for the local and regional reconstruction of vegetation history. The chemical composition of the core and the determination of amorphous Fe and Al phases enabled to trace back soil formation in the surrounding catchment. About 11 ka ago, birch-pine and pine-birch communities started to develop in the Preboreal chronozone. Subsequently, the vegetation cover changed to Corylus–Picea–Abies + Fagus in the higher and middle mountain zones, and to Ulmus–Quercus–Carpinus in the mountain foreland and footslopes. The decline of forests that started in the 11th century because of clearing was accompanied by the expansion of grasses, both as pastures in the mountains and cereal crops in the foreland. At the same time, the mining and smelting gave rise to environmental pollution with heavy metals (Pb, Cu and Zn) at a regional scale. Combined geochemical and palynological data indicated relationships between vegetation type, sediment texture and its elemental composition. This relationship seemed to be linked to climatic conditions and surface erosion intensity. A first progressive soil-forming phase occurred from 10.9 until about 8.4 ka cal. BP. Rapid and strong soil erosion (regressive phase), related to rapid climate deterioration, occurred at about 8.4 ka cal. BP. Thereafter, continuous soil formation (progressive phase) and podzolization in the Boreal and Atlantic continued until about 1 ka BP when strong human impact (deforestation) led again to a regressive soil evolution

Rock-type control of Ni, Cr, and Co phytoavailability in ultramafic soils

Background and aims Ultramafic soils constitute an extreme environment for plants because of specific physico-chemical properties and the presence of Ni, Cr, and Co. We hypothesized that type of ultramafic parent rock depending on their origin affects the composition of soils and plants. Therefore, phytoavailability of metals would be higher in soil derived from serpentinized peridotite compared to serpentinite because of differences in susceptibility of minerals to weathering. Results Based on DTPA-CaCl2 extractions, we noted that soil derived from the serpentinized peridotite is characterized by a higher phytoavailability of Ni compared to soil derived from the serpentinite. On the contrary, plant species growing on soil derived from the serpentinite contain higher concentrations of metals

Aeolian silt contribution to soils on mountain slopes (Mt. Ślęża, southwest Poland)

AbstractThis paper evaluates the possible contribution of aeolian silt to soils of Mt. Ślęża (southwest Poland). Silt loam textures are common across Lower Silesia and are often confused with silt clay loam, especially at the outer boundaries with thin loess deposits. Eight study sites with different thicknesses of silt loam mantles that are covered and/or mixed with underlying sediments were examined in the field. To test our hypothesis, we analyzed the particle size and geochemistry of representative horizons. Concentrations of major and trace elements as well as their cross ratios confirmed the aeolian origin of silt loam materials and clearly distinguished them from basal sediments. There is a clear relationship between the presence and depth of aeolian mantles and mixing zones with the type of underlying material. Furthermore, the incorporation of aeolian silt to regoliths/soils was a main agent initiating and stimulating clay translocation leading to the formation of an argic horizon below the silt mantles. Mixing aeolian silt with acid granite regoliths and further illuviation resulted in the formation of alisols, while silt contributions to serpentine sediments resulted in development of skeletic luvisols. Soils receiving very weak input of aeolian silts remain as leptosols/cambisols.</jats:p

Tracking textural, mineralogical and geochemical signatures in soils developed from basalt-derived materials covered with loess sediments (SW Poland)

This study investigates the scale of inheritance of signatures typical of loess- and basalt-derived substrates in soils having both components present as parent material due to past periglacial processes. Based on field description, particle size distribution, mineralogy (heavy minerals and clay minerals) as well as geochemistry we track the signal of both materials (local basalt-derived and loess-derived), estimate the maximum thickness of loess mantles and mixed zones (having both loess and basaltic components), and note the presence or absence of basal layers without allochtonous additions. The results show that geochemistry and heavy minerals are the most reliable proxies for a verification of aeolian silt contributions and to define individual layers in complex soil parent materials. Soil formation in the studied landscape depends on the type of slope sediments. Typical fine-grained weathering of basalt without input from aeolian silt would promote rather vertic development. However, in thick loess deposits as well as in thin silt-textured materials superimposed on clay loam beds, clay illuviation dominates. Development of argic horizons, however, results in decreasing permeability, promoting water stagnation and enhanced degradation processes in clay-rich subsoil. Instead of Luvisols, Stagnosols and Retisols developed in the study regions. Basaltic block covers mixed with loess host cambic horizons. Based on our findings it seems that at the edge of thin loess deposits no soils exist that developed exclusively from basaltic parent materials