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Formation and development of a 1st-order valley network in postglacial areas (the Dębnica catchment)

Mazurek M., Paluszkiewicz R.

Landform Analysis

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2013

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Vol. 22

75--87

EN

This article describes the formation and development of the 1st-order valley network in the postglacial catchment of the Dębnica River (NW Poland). Its valley network is an example of a system of polygenetic depressions, and its 1st-order sections are comprised of denudational hollows and valleys, dissections, and erosional-denudational valleys. In the article, both landforms with no permanent flow and those nourished by groundwater and included in the river runoff network are characterised. In the course of their development, dry valleys have continued to grow in width and length, while the gradient of their bottom has decreased due to slope wash processes. In groundwater outflow zones, in turn, the modelling of their slopes indicate retreat as a result of seepage erosion and mass movements, which has led to the preservation of their convex parts and the development of a concave section at the foot, passing into the flat bottom of an alcove. In headwater alcoves, which mark the start of a valley or are inserted into older valley landforms, morphological contrasts are enhanced because of an increase in their width and depth, as well as changes in their cross-profile.

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Uwarunkowania rozwoju i wybrane właściwości gleb dolinki erozyjno - denudacyjnej Wieprzy w okolicach Mazowa

Jonczak J., Kuczyńska P.

Landform Analysis

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2008

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Vol. 7

69--79

PL

Celem badań była analiza przestrzennego zróżnicowania procesów i czynników glebotwórczych oraz właściwości pokrywy glebowej głęboko wciętej dolinki erozyjno-denudacyjnej Wieprzy w okolicach Mazowa (Równina Sławieńska, Polska północna). Badania wykazały, że mimo niewielkich rozmiarów dolinki erozyjno-denudacyjnej, w jej obrębie występuje duża różnorodność czynników i procesów glebotwórczych. Gleby dolinki zaklasyfikowano do czterech typów (brunatne kwaśne, deluwialne brunatne, deluwialne próchniczne, torfiasto-glejowe). Wykazują one dużą zmienność przestrzenną zarówno pod względem pozycji systematycznej, jak i morfologii oraz właściwości fizycznych i chemicznych.Wobrębie dolinki wyraźnie zaznaczają się trzy strefy – część wysoczyznowa, stoki i dno. Z każdą z tych stref związany jest inny kompleks czynników i procesów glebotwórczych.Wrozwoju gleb, w skali całej dolinki, podstawową rolę odgrywa rzeźba terenu, a procesy glebotwórcze pozostają w ścisłym związku z jej morfogenezą.

EN

The aim of research was an analysis of spatial differentiation of soil-forming processes and factors, as well as of soil properties, in a deeply incised erosional-denudational valley of Wieprza near Mazów, northern Poland. Despite small size of the valley, there exists considerable variability of soil-forming factors and processes within its limits, hence soil systematic position, morphology, and physico-chemical properties vary across the valley. Soils in the valley belong to four types: acid brown soils (cambisols), deluvial brown soils, humic deluvial soils and peaty-gley soils. Three main landscape elements can be distinguished within the study area: upper surfaces, valley sides, and valley floor. Each zone is typified by its own complex of soil-forming factors. In the upper slope/plateau area soil properties reflect the characteristics of parent rock. Loamy deposits of former ice-dammed lakes support acid brown soils of low pH, high content of organic matter in the humic horizon, and completely depleted in carbonates. Slopes below are subject to erosion, hence the thickness of humic horizon and organic matter content are reduced in respect to soils present on the plateau. In slope concavities one can observe deposition of material brought down by slope wash and the build-up of deluvial soils. These soils show the development of cambic horizon, which typically contains large quantities of organic matter. In the valley floor mud deposition and the development of humic deluvial soils takes place. The latter are enriched in organic matter, nutrients, favourable C/N and C/P ratio, and have higher pH if compared with soils on the slopes and on the plateau. Their evolution remains under significant influence of water seeping from the truncated water-bearing horizons and, seasonally, water issued from drains. The surplus of water is conducive for peaty-gleyey soil development. At the entire valley scale, local relief is a key factor influencing soil evolution, whereas soil-forming processes remain in close correspondence with morphogenesis of the valley.

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Relief and deposits of erosional-denudational valleys in the Carpathian Foothill region – the Wiśnicz Foothill

Michno Anna, Maciejczyk Karolina

Studia Geomorphologica Carpatho-Balcanica

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2019/2020

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Vol. 53/54

113--136

EN

The paper discusses variances in the relief of erosional-denudational valleys that are scattered across the woodland areas of the threshold of the Carpathian foothill region – in the Wiśnicz Foothills. Relief in the study area was characterized via geomorphological mapping and analyses of cartographic materials such as a LIDAR DEM. The paper also discusses valley types and valley morphometry along with the diversity of morphogenetic processes occurring in the study area. Deposits forming the floors of the studied valleys were also characterized through the use of 12 geologic drilling sites. The resulting data included the deposit grain size range and degree of deposit sorting. In the section on the analysis of present-day relief and relief evolution, the research focuses on the joint action of landslides and fluvial erosion. The following sequence of valley types is discussed for the main valleys presented in the study: denudational trough or gully, active V-shaped valley, V-shaped valley with a flat accumulation floor – found near the mouth of the watercourse. Active V-shaped valleys are characterized by the presence of short but numerous valley sections featuring predominant downcutting erosion or small, local accumulation zones. In this case, the presence of these sections is determined by the intensity of landslides on hill slopes in the studied valley, influx of material from tributary valleys, erosional capacity of local streams, and the presence of woody or rock steps in stream channels. The characteristics of deposits composing valley floors, described in the present study, indicate large differences in deposition process energy and short-distance transport of mineral-type material in stream channels. Research has shown significant complexity of regional factors and local factors affecting the evolution of small erosional-denudational valleys in forested areas in the southern part of the Wiśnicz Foothills. The location of the study area in the Silesian unit overthrust associated with the presence of a visible morphologic threshold, the middle foothills threshold, leads to significant, local differences in elevation, high degree of hill slope fragmentation, high activity of morphogenetic processes, and also affects the impact of these processes on deposits forming the floor of the studied valley.