Geology Reference
In-Depth Information
of 1 mm or more within a few decades. The main
bare forms resulting from surface wetting are
solution
ripples
,
solution flutes
(
Rillenkarren
),
solution bevels
(
Ausgleichsflächen
),
solution runnels
(
Rinnenkarren
),
and
decantation runnels
and
flutings
(Table
Solution flutes
(
Rillenkarren
)
Planar belt of no
channelled erosion
8.2;
Hortonian-type
runnels
Figure 8.6; Plates 8.1 and 8.2).
Bare forms resulting from concentrated runoff are
microfissures, splitkarren, grikes, clints, and solution
spikes.
Microfissures
are solutional features following
small joints.
Splitkarren
are larger solution channels that
run along larger lines of weakness - joints, stylolites, and
veins.
Grikes
(
Kluftkarren
), which are called solution
slots in America, follow joints and cleavage planes, so
may be straight, deep, and long, often occurring in net-
works (Plate 8.3). Grikes are the leading karren feature in
most karren assemblages. Large openings may develop at
joint intersections, some several metres deep and called
karst wells, which are related to solution pipes and pot-
holes. The intervening tabular blocks between grikes
are called
clints
(
Flackkarren
) (Plate 8.3). Grikes in
upright bedding planes are enlarged in the same ways
as joints in flat bedding planes and are called
bedding
grikes
(
Schichtfugenkarren
). However, residual blocks
left between them commonly break into
pinnacles
or
solution spikes
(
Spitzkarren
) and beehives decorated
by solution flutes. In horizontal strata, the near-surface
bedding planes are likely to be opened up by seepage.
This process may free the intervening clints and lead to
their breaking up to form
shillow
(a term from northern
England), which is roughly equivalent to the German
Trümmerkarren
and
Scherbenkarst
. All these forms are
small. Grikes average about 5 cm across and up to several
metres deep, clints may be up to several metres across,
and solution spikes up to several metres long. Large-scale
grikes, variously termed
bogaz
, corridors, and streets, are
found in some areas and follow major joints and faults.
Bogaz
are up to 4 m wide, 5 m deep, and tens of metres
long.
Karst corridors
and
streets
are even larger and take
the form of gorges.
Decantation runnels
1
2
3
1.
2.
Source not in direct contact with surface
Source in direct contact with surface
Source no longer present
3.
Diffuse
sheet
flow
Decantation
flutings
Figure 8.6
Solution flutes (
Rillenkarren
), decantation
runnels, and decantation flutings.
Source:
After Ford and Williams (1989, 383)
Covered and partly covered forms
Partly covered forms develop in areas with a patchy
soil, sediment, litter, or moss cover.
Solution pits
are
round-bottomed or tapered forms, usually less than 1 m
