Several possibilities to present and to interpret the results of granulometric analyses of Quaternary fluvial, aeolian, glacial and wash-out slope deposits were investigated. Attention is paid particularly to the cumulative curves at a probability scale and the frequency curves, and it is shown how these curves can help to determine the sedimentary environment. The inclination of the cumulative curves in the part of the maximum proportion of a particular grain size appears significant. It appears possible to obtain information on the density and dynamics of the transporting medium from the course of the cumulative curves (inclination and spread of grain size).The examination of textural parameters allows to draw regression lines characteristic of both deposits from various sedimentary environments and deposits from one single environment but with different histories as to their transport dynamics.
The composition of the transparent heavy-mineral assemblages (0.25-0.1 mm) in Quaternary slope, karst, glacial, fluvioglacial and fluvial deposits with different parent material was investigated in the Kielce-Łagów Valley (the central part of the Palaeozoic core of the Holy Cross Mountains). For the purpose, 93 samples of mostly sandy sediments were examined. Some marker and some supporting minerals can be distinguished. Slope and karst deposits are dominated by the abrasion-resistant minerals zircon, tourmaline, staurolite and rutile. This assemblage points at a source consisting of strongly weathered pre-Quaternary bedrock. Glacial and fluvioglacial deposits are dominated by medium-resistant and non-resistant minerals (garnet, amphibole, pyroxene and biotite). The two types of parent material of the heavy minerals are typical of the Quaternary deposits in the Polish uplands. The two sources are most clear in the younger (Vistulian and Holocene), mostly fluvial sediments. The results of the analysis imply that the impact of Pleistocene glaciers on the central part of the Holy Cross Mountains was neither large enough to hide the local mineralogical background, nor sufficient to dominate over the main processes transforming the mineral composition under the variable climatic conditions of the Quaternary, including aeolian processes and chemical weathering.
The heavy-mineral assemblages of Pleniglacial fluvial sediments were analysed for two river valleys, viz. the Luciąża River (at Kłudzice Nowe) and the Belnianka River (at Słopiec). These sites, on the Piotrków Plateau and in the Holy Cross Mountains respectively, are located in different morphogenetic zones of Poland that were affected to different degrees by the Middle Polish ice sheets. The study was aimed at determining the kind of processes that modified the heavy-mineral assemblages in the two fluvial sediments, at reconstructing the conditions under which these processes took place, and in how far these processes caused changes in the assemblages. The heavy-mineral associations of the parent material was taken as a starting point; this parent material were the sediments left by the Odranian glaciation (Warta stadial = Late Saalian). It was found that heavy-mineral assemblages in the Luciąża valley deposits are varied, particularly if compared with other fluvioglacial Quaternary deposits from the Polish lowlands, with a dominance of garnet. In the fluvial deposits of the Belnianka valley, zircon, staurolite and tourmaline dominate, with minor amounts of amphibole, pyroxene, biotite and garnet. This suggests that the deposits were subject to intensive and/or persistent chemical weathering and underwent several sedimentation/erosion cycles under periglacial conditions. In both valleys chemical weathering and aeolian processes were the main factors that modified the assemblages of the transparent heavy minerals; these processes were largely controlled by the climatic changes during the Pleistocene.
Relict periglacial slope cover deposits in the Holy Cross Mountains of Poland are composed of material derived from bedrock, loess and sand of polygenic origin. The aim of this study was to interpret the processes that deposited three massive coarse‐grained diamictons near the base of gentle hillslopes. Based on macroscopic and microscopic sedimentological analyses, the diamictons are attributed to deposition by three processes – active‐layer detachment, solifluction and high‐energy overland flow – due to climatic and geomorphologic factors. The use of microscopic analysis revealed the detailed texture and structure of these deposits, and was particularly important in interpreting fine‐grained sediments produced by low‐energy overland flow. This technique served as the basis for the differentiation of solifluction deposits and high‐density flow deposits. The active‐layer detachment deposit (adjacent to the slip plane) was characterised by a heterogenous texture and breccia‐type structure with domains and clasts oriented parallel to the slope. The deposit included erosional surfaces and individual slip planes. The solifluction deposit was a clayey diamicton with a banded structure oriented parallel to the slope. The low‐energy overland flow deposit was laminated and sorted with laminae oriented parallel to the slope. The high‐energy overland flow deposit was a homogeneous and massive diamicton with a silty/sandy matrix and randomly oriented clasts and grains. The following characteristics helped identify the sediment type: the degree of homogenisation, texture, sedimentary structure and fabric. Features including plasmic fabric, deformation structures and microporosity played an additional role in identifying the studied deposits. In relict slope deposits, these features may be formed as a result of depositional or postdepositional processes. Copyright © 2015 John Wiley & Sons, Ltd.
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