what are the slope theories

/what are the slope theories
what are the slope theories 2015-09-19T18:53:51+00:00
QuestionsCategory: Geographywhat are the slope theories
Anonymous asked 3 years ago

explain slope theories

1 Answers
Wiseone Staff answered 3 years ago

I am going to assume you are referring to slope evolution theories as mentioned in the A Level Geography syllabus.
Slope evolution:  is the change in slope form with time, as brought about by the action of processes. Three models of slope
evolution have been put forth: these are called slope decline, slope replacement, and parallel retreat.
Slope decline
– Slope decline is common in many humid temperate regions.
– Steepest slopes at beginning of process with a progressively decreasing angle in time to give a convex upper slope and
a concave lower slope.
– The movement of rock waste is seen as one stage between weathering on the one hand and transportation by rivers
on the other. The forms of slopes change as the cycle of erosion advances. When slopes are first developed they
are steep and covered with coarse material. Later in the cycle the graded slopes are gentler and are covered with
a thicker layer of finer material. The slope decline is caused by the fact that the downwash of soil from convex upper
slopes is faster than its removal from the slope base.
Slope replacement(W. Penck, 1924)
– The theory of slope replacement is particularly applicable to explaining the slope development of cliff in subtropical
semi-humid climatic areas.
– The maximum angle decreases as the gentler lower slopes erode back to replace the steeper ones giving a concave
central portion to the slope.
– This theory assumes that the surface of the slope is weathered evenly and crumbles – the fragments (scree) falling to
the base. Thus maximum angle of the slope decrease and is replaced by a gentler slope.
Slope retreat (or Parallel retreat) (L.C. King, 1948, 1957)
– The theory of slope retreat is particularly applicable to explaining the slope development in semi-arid areas. Sea cliffs
with wave-cut platforms.
– The maximum angle remains constant as do all slope facets apart from the lower one which increases in concavity.
– Each of the upper parts of the slope retreats by the same amount and maintains the same angle. Thus the convexity,
free face and debris slope all retain the same length, both absolute and relative to each other during retreat. The
pediment extends in length and becomes slightly gentler in angle.