Geology Reference
In-Depth Information
Table 5.2 Landforms associated with sedimentary rocks
Formative conditions
Landform
Description
Horizontal beds
Not dissected by rivers
Sediplain
Large sedimentary plain
Dissected by rivers with
thin caprock
Plateau
Extensive flat area formed on caprock, surrounded by
lower land, and flanked by scarps
Mesa or table
Small, steep-sided, flat-topped plateau
Butte
Very small, steep-sided, flat-topped plateau
Isolated tower, rounded peak,
jagged hill, domed plateau
Residual forms produced when caprock has been
eroded
Stepped scarp
A scarp with many bluffs, debris slopes, and structural
benches
Ribbed scarp
A stepped scarp developed in thin-bedded strata
Debris slope
A slope cut in bedrock lying beneath the bluff and
covered with a sometimes patchy veneer of debris
from it
Dissected by rivers with
thick caprock
Bluffs, often with peculiar
weathering patterns
Straight bluffs breached only by major rivers.
Weathering patterns include elephant skin
weathering, crocodile skin weathering, fretted
surfaces, tafoni, large hollows at the bluff base
Folded beds
Primary folds at various
stages of erosion
Anticlinal hills or Jura-type
relief
Folded surfaces that directly mirror the underlying
geological structures
Inverted relief
Structural lows occupy high areas (e.g. a perched
syncline) and structural highs low areas (e.g. an
anticlinal valley)
Planated relief
Highly eroded folds
Appalachian-type relief
Planated relief that is uplifted and dissected, leaving
vestiges of the plains high in the relief
Differential erosion of
folded sedimentary
sequences
Ridge and valley topography
Terrain with ridges and valleys generally following the
strike of the beds and so the pattern of folding
(includes breached anticlines and domes)
Cuesta
Ridge formed in gently dipping strata with an
asymmetrical cross-section of escarpment and
dip-slope
Homoclinal ridge or strike
ridge
Ridge formed in moderately dipping strata with just
about asymmetrical cross-section
Hogback
Ridge formed in steeply dipping strata with symmetrical
cross-section
Escarpment (scarp face, scarp
slope)
The side of a ridge that cuts across the strata. Picks out
lithological variations in the strata
Dip-slope
The side of a ridge that accords with the dip of the strata
Flatiron (revet crag)
A roughly triangular facet produced by regularly
spaced streams eating into a dip-slope or ridge
(especially a cuesta or homoclinal ridge)
Source: Partly after discussion in Twidale and Campbell (1993, 187-211)
 
Search WWH ::




Custom Search