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Geosciences LibreTexts

9.3: Relief

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    Hillslope positions across a landscape Wysocki et al., 2000 and Schoeneberger et al., 2012

    Summit The top or highest level of an upland feature such as a hill or mountain. Usually, the summit is relatively level.
    Shoulder Forms the uppermost inclined surface at the top of a hill slope. It is the transition zone from the summit to the backslope of an upland. The surface is dominantly convex in profile and erosional in origin.
    Backslope The steepest inclined surface of the hill slope. Backslopes in profile are commonly steep and linear, or steep and convex-concave. Backslopes are erosional forms produced mainly by mass wasting (direct gravitational action) and running water action.
    Footslope The inner, gently inclined surface at the base of a hill slope. The surface is dominantly concave in profile. It is a transition zone between the backslope and toeslope where colluvium and alluvium accumulate.
    Toeslope The outermost, gently inclined surface at the base of a hill slope. Toeslopes are constructional surfaces forming the outermost point of a hill slope where alluvium tends to accumulate.
    Stream terrace A natural level strip of land in a stream valley, parallel to the stream channel, originally formed near the level of the stream, and representing the dissected remnants of an abandoned flood plain or stream bed.
    Flood plain The nearly level fluvial (river) plain bordering a stream and subjected to periodic inundation and sediment accumulation under flood stage conditions. It is a constructional landform built of sediment deposited during overflow and lateral migration of the stream.

    Parent Material

    When rocks are exposed to atmospheric conditions, they begin to adjust to their new environment. This adjustment (known as weathering) involves processes which cause physical disintegration and chemical decomposition of the rocks. The weathering of bedrock produces unconsolidated debris serving as the parent material for soils. The parent materials undergo continued alteration and evolve into a soil reflecting the integrated effects of climate, biotic factors (plants, animals, and microorganisms), topography, and time.

    Some common parent materials of the Laramie area are alluvium, colluvium, and residuum.

    Alluvium Unconsolidated material transported and deposited by flowing water.
    Colluvium Unconsolidated material deposited on and at the base of steep slopes by direct gravitational action.
    Residuum Unconsolidated weathered mineral matter accumulating by disintegration and decomposition of bedrock in place.
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