Regional Landform (dominant soil landscape)
|Title||Regional Landform (dominant soil landscape)|
General physical description.
For areas of the country not mapped in version 1.0, a value of '-' was assigned.
This information was originally found in SLC verson 1.0. It was translated to version 2.2 using a polygon intersection approach.
|Classes||Regional Landform: 9 classes. First used in SLC 2.2.|
|B||Tableland (or plateau)||
Comparatively flat areas of great extent commonly bounded on at least one side by an abrupt escarpment, or may be terminated by mountains; may be dissected by deep valleys and deeply incised rivers; may be tectonic, erosional, or volcanic in origin; may be step-faulted; slopes generally <10%, in some places 10-15%; relief generally <50 m.
Natural elevations rising prominently above the surrounding plain and having a recognizably denser pattern of generally higher knolls or crest lines with an irregular or chaotic surface form composed of upper surface convexity and lower concavity; includes hummocky morainal material, volcanic cones, and conical hills or lava; slopes generally 10 - 30%; relief generally <100 m.
Erosional and volcanic landscapes with relief (vertical distance between higher and lower parts) ≥300 m with most of the area comprising valley to summit terrain; slopes generally >30%. In general the terrain has a restricted summit area and steep sides, irregular shape and considerable bare rock surface, or very thin soil cover; occur as a single, isolated feature or in a group forming a long chain or range; major scarps are relatively steep and straight cliff-like slopes of considerable linear extent separating surfaces such as plateaus lying at different levels.
Areas dominated by organic material >40 cm thick; contains >30% organic matter by weight; occurs in a variety of wetland surface forms.
Flat to very gently undulating areas having few or no prominent irregularities; formed by erosional or by depositional (or constructional) processes; include broad continuous, gently sloping piedmont plains extending along and from the base of a mountain, formed by lateral coalescence of a series of separate but confluent alluvial fans; alluvial processes are mainly responsible for the sedimentation; coarse fragments are rounded by transport over relatively long distances; slopes generally <6%; relief generally <10 m; extent generally >5 km in one direction.
An escarpment, cliff, or steep slope of some extent along the margin of a terrace, bench, plateau, hill, or mesa; a scarp may be of any height.
Terrain dominated by major spillways, drainageways, or mountain trenches separated from surrounding landforms by a significant and abrupt break in slope; the valley profile may be V- or U-shaped with an extensive valley floor and flood plain up to about 5 km wide; valley profile may also include eroded terraces and their irregular slope segments.
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