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92 Erdkunde Band XVIII
schungskorrosion, die beim Vermischen verschie
den temperierter Wasser auftritt. Beim Abkiihlen
wird weiterhin C02 frei,was zur Korrosion fiihrt:
Durch diese vier Korrosi
Abkuhlungskorrosion.
wird
der ganze verkarstungs
onsmoglichkeiten
in Karbonatgesteinen
in seinem
fahige Raum
zu einer Ganzheit
Werden
zusammengeschlossen.
Literatur
?
A.: Probleme
der Karrenbildung.
Bogli,
Geographica
H. 3, 1951.
Helvetica,
?
?:
Re
Der Chemismus
im Karst.
der Losungsprozesse
in Karst Phenomena,
port of the Commission
IGU, New
1956.
York,
?
?:
im Muotatal.
Untersuchungen
Karsthydrographische
1960.
Basel
Regio Basiliensis,
?
?:
fiir Geo
Zeitschrift
und Karrenbildung.
Kalklosung
1960
Bd. 2: Karstmorphologie,
Suppl.
morphologie,
?
?:
Leben und Umwelt H.
Das Holloch
imMuotatal.
19,
1963.
?
von Karsthohlen.
Die Hohle,
Beitrag zur Entstehung
1963.
Wien
3,
?
Inst, des etu
de l'Europe.
Corbel,
J.: Les Karst du NE
des rhodaniennes, Memoires
12, Lyon 1957.
?:
en terrain calcaire. ?
de Geographie,
Annales
Erosion
H. 366.
?:
H.
Gmelins
der anorganischen
8. Auflage.
Handbuch
Chemie,
?
W. R.: Changing
of Speleogenesis.
Halliday,
Concepts
Bulletin
Vol.
of the National
22,
Society,
Speleological
1960, USA.
Tabellen.
Landolt-Bornstein:
Physikalisch-chemische
?
Karstwasser.
H.:
kubanischer
Chemismus
Lehmann,
Briefl. Mitt.
?
O.: Hydrographie
der
des Karstes.
Lehmann,
Enzykl.
1932.
Erdkunde, Wien
to the Origin
G. W.:
of Limestone
Introduction
Moore,
?
Caves.
of the National
Bulletin
Society,
Speleological
Vol. 22, 1960. USA.
von Karstgewassern.
H.:
Karbonatharte
?Stalac
Oertli,
tite" 1953.
Kal
des kohlensauren
iiber die Loslichkeit
Pia, J.: Theorien
?
1953.
kes.
Mitt. Geol. Ges. Wien,
H.:
der Bestim
Theoretische
SchmasSmann,
Grundlagen
in naturlichen Gewas
mung von agressiver Kohlensaure
sern.
und
f. angewandte
Wissenschaft
Schweiz. Archiv
1947.
Technik, Jg. 13?14,
von Wasser
und
chemische Untersuchung
Tillmans,
J.: Die
?
1932.
W. Knapp, Halle,
Abwasser.
?
1952.
F.: Traite de Speleologie.
Paris,
Trombe,
B.: Terminations
of Passages
in Appalachian
W.
White,
?
as Evidence
Bul
Phreatic Origin.
for a Shallow
Caves
letin of the NSS, Vol. 22, 1960, USA.
Freie Kohlensaure
Zehender-Stumm-Fischer:
und pH von
und Wasserfachman
Wasser. ?
Schweiz. Ver. von Gasnern, H.
11, 1956.
SOME FACTORS IN THE ABSOLUTE DENUDATION
OF LIMESTONE TERRAINS
With 1 photo and 6 figures
M. M.
Sweeting
Such values are therefore probably only a rough
for bringing our
We are indebted to Corbel
attention to themean rates of erosion of limestone
guide to the range of intensity of chemical denuda
tion. It is also difficult to be sure that the mean
areas and particularly for stressing the variations
is
It
differences
(1).
figures give a realistic picture of chemical denu
dependent upon temperature
dation in a limestone area. There is therefore a
quite clear however that solution rates in lime
need for the systematic observation and analysis
stones are dependent upon many factors, of which
of limestone waters and springs in order to isolate
one.
Hence
Corbel's
is
figures
temperature
only
rates
to
the factors which may be causing the variations.
the real
though useful are not a true guide
of solution which may be occurring in a given area. With this aim inmind a series of observations of
This contribution seeks to point out some of the
springs and waters in many parts of the British
results
Isles has been started. The preliminary
factors.
other
show that in a small region such as the British Isles,
If the rates for themean, maximum and minimum
rates of chemical erosion for various rivers are
quite significant variations in solution rates may
are
be observed.
examined it will be seen that these figures
In N. W. England, the area best known to the
extremely variable.
Tarn
writer, the figures given for the Malham
are
the
limestone
for
1
waters
in
Table
fairly typical
fig.
(Figures supplied by I. Douglas,
Ballioc College, Oxford [2])
solubility of the springs and waters of the district.
Rates of chemical denudation
ms/km2/year
The calcium content in general varies inversely
with the discharge. The average calcium content
Minimum
Maximum
Mean
River
of waters varies from about 140-180 p. p. m. The
Thames (Teddington)
288,0
12,87
104,0
on to the curves of Trombe,
figures when plotted
Derwent
65,92
197,4
(Matlock Bath)
are more or less in equi
waters
the
show that
3,44
297,0
63,75
Kentucky
(U. S. A.)
Lee (Essex)
libriumor only slightlyaggressive(fig. 2). The
23,05
63,36
155,0
Kissimmee
26,94
(Florida)
values for a dry period and for the summer months
63,04_15,90
M. M.
Some
Sweeting:
factors
in the absolute
denudation
of limestone
terrains
93
Oct.
Nov.
Dec.
Jan.
Feb.
March
June
Sept.
July
Aug.
April
__r_rn?,
May
9
3 10 17 24 31 7 14 21 28 7 14 21 28 5 12 19 26 3 10 17 24 31 7 14 21 28 5 12 19 26 2 9 16 23 30 6 13 20 27 4 11 1824 31 6 15 22 29 6 13 20 28
i |-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1?
200i-1-\-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1-1
190_
-Water
180- ?.
Water
Tarn
flowing into Malham
Tarn a
flowing out of Malham
Aire Head
-?p\
Springs
\
V
-^-c-\-y1
-
120110-
/
^
\
Nv
I l_I_I_I_I_I_I_I_I_I_I_I_I_I_I_I_I_I-1-1_I-1-1_I_I-1_I-1_I_I-1_I_I_I_I_I_I_I_I_I_I_I_I_I_I_I_I_I_I_I_
10J 3 10
17 24 31 7 14 21 28 7 14 21 28 5 12 19 26 3 10 17 24 31 7 14 21 28 5 12 19 26 2 9 16 23 30 6 13 20 27 4 11 18 24 31 6 15 22 29 6 13 20 28
Jan.
Feb.
March
June
Oct.
Nov.
April
Dec.
July
May
Aug.
Sept.
Fig.
20
inn.
i i 60.
i r~i 80..
i
lu/ui . H i f?.
9,5
content
-1-1
z
80
-V--4iE
80-^^^^-
aggressiv
I_-?30
"^^^^5^^2o
e_ 30
6,5^-40
6,5-1-AQ
1*
6/0
50
100
150
200
_I_I_I_I
0
5
10
15
20
Fig.
2: Malham
250
I
25
300
I
30
Tarn
350
I
35
System
400
_| I
40
.
450 m9
CaC?3/L
0
45?fH
Fig.
6'?
aggressiv
I
2+
50
I
5
I
3:
1
2
3
4
are relatively saturated, those for a wet
period and
for winter being more aggressive (fig. 3).
of the calcium content of pools and
Examination
pans at selected periods after rain shows that the
calcium is taken up relatively quickly after rain:
the waters contain 120-140 p.p.m.
after a short
interval of time or after having flowed for only a
few metres upon the bare rock. Subsequently rela
tively little calcium is picked up. Figure 4 shows
the relationship
of dissolved
total hardness
(MgC03 + CaC03)
180 200
saturated
^
~-1-1-9-??%-
ccl_I
160
-V-1-1
saturated
^
90
-V
Tarn waters
of the Malham
Du rngC02/L semi-comb. mg C02/l semi-comb.
120 uo
160 180
200 i
20
40
60
80
120 UP
100
i
i
n
I
|
n?i-1?pi-1?i
lU/Ui-1-n?i-n?i-1?r~i-1?p?~~i-1-i-1?i-n?i-rrn-1?i
100
-V-1-1-9/5
1: Calcium
to thedissolvedCaC03, and
shows that this is a straight-forward
connection.
3o
"^^^^5^31
4.
100
I
10
150
I
15
200 '
I
20
250
I
25
300
I
30
350
I
35
400
I
40
.
450m9
I CaC03/l
45?fH
N.
W. England
Limestone waters
in summer
Limestone waters
in winter
Inflow to Malham
Tarn
(N. W. Yorks.)
Great Close Springe (N. W. Yorks.)
If these figures for N. W. England are used in
conjunction with Corbel's
formula, then the
average lowering of the surface by chemical denu
dation per kilometre square is of the order of
0.04 mm. per year (1). The amount of
lowering
since the end of the last phase of the
Quaternary
Ice Age should then be of the order of 40-50 cm.
The pedestals of the well-known Norber boulders
inN .W.Yorkshire fit in very well with this type
of calculation (photo), and support the idea of a
general lowering of this amount inNorthern Eng
land, since the Quaternary
(3). In several other
94 Erdkunde Band XVIII
E 250i-1-1-1-1
d
d
<n
i/>
o
c
T3
/
i
E 200 -/
<'
I
*
/
150-A^r
xx\*
/*?
.3?
100
/
/
'
50
100
50
Fig. 4:
Malham
1x
2
250
200
Total Hardness p.p.m.
150
Area
(N. W.
Yorks.)
in South West England also
The Mendip Hills
form limestone terrain and many thousands of
measurements of the calcium content of thewaters
have been made by members of Bristol University
(5). The figures for the springs in the Mendip
area are in general very consistent, averaging
about 220-240 p. p. m. These results are explained
as due to the great concentra
by Smith and Mead
tion of soil C02 consequent upon a complete grass
cover. A further point made by these two authors
concerns the importance of the length of time the
limestone has been in contact with the waters and
the
the depth of penetration of those waters;
greatest concentrations of calcium seem to occur in
those springs and waters which have been in con
tact longestwith thelimestones (5).Hence the lower
and deeper the percolation, the greater the solution
and the actual chemical denudation, a result which
might be inverse to the rates of mechanical denu
dation.
Other observations
below:
in the British Isles are given
Cambrian
Limestones,
Durness, N. Scotland
Carboniferous Limestones,
S.Wales
Carboniferous Limestones,
Clare, W. Ireland
Jurassic Limestones,
290
Cotswolds
Chalk of Southern England
Photo
1: Pedestal
of the Norber
inN. W. Yorkshire
boulders
similar limestone
localities inNorthern England
pedestals can be found. Locally, solution rates,may
be relatively greater, particularly where favourable
conditions
occur.
In the Southern Pennines, only a 100 kilometres
or so south of the areas just considered, Piggott
has produced evidence for a very similar rate of
lowering of the limestone surface since the end of
the lime
the Quaternary
(4). In N.W.England
stone was glaciated during the period of theNewer
Drift, whereas the limestone of the Southern Penni
nes is believed to have remained ice free.As a result
much of the limestone of N. W. England
ismade
up of bare pavements, while that in the Southern
area is grass covered. This fact may inpart explain
themuch higher figures for the amount of calcium
in thewaters of the Southern Pennines, about 230
250 p.p.m.;
such figures if plotted on Trombe's
curves show that the waters are saturated (fig. 5).
Calcium
60-
content
80 p. p. m.
80-100
120-134
p.p.m.
p. p. m.
p. p. m.
p.p.m.
These
results thus indicate that amounts of
calcium picked up by percolating waters are not
dependent upon temperature variations and that
lithology and nature of the vegetation must also
be taken into account.
Returning toCorbel's
graphs inhis 1959 paper,
seem that they refer to potential agres
itwould
sivity and saturation of the waters rather than to
actual solution rates. Individual variations in the
calcium content of waters occur from place to
place but no systematic variation on a world scale
can be shown to exist.
such as suggested by Corbel
This can be seen from the following figures:
280-300
Calcium
214
Cockpit Country, Jamaica
139-200
Africa
North
Cyrenaica,
140-150
Dinaric Coast
Yugoslavia,
200
N. W. Australia, Fitzroy Area
These
obtained
content
p. p. m.
p. p. m.
p. p. m.
p. p. m.
figures should be compared with those
from areas in the British Isles. Figure 6,
compares the results of two districts in southern
this shows that
Australia,
(New South Wales),
while the aggressivity of thewaters may be greater
in the cooler region, the rate of actual limestone
solution is greater in the warmer region.
Bauer:
Fridtjof
Kalkahtragungsmessungen
mg C02A semi-comb.
60
120 UP
160 180 200
100
20
40
80
10,0]-1-n?i-n?i-r?p-1?p?lt?i-1-1?i-rj?i-r-p-1?|
9,5-V-1
^
?
9,0
1
6'?
0
mg CO2/L semi-comb.
120 UP
160 180 200
80
100
40
20
60
10,01-1-n?1-n?1-i?p-1?n?nr?1-1-1?1-rj?1-i?p-1?
u
V saturated
saturated
9/0 m
*
aggressiv # ^^^^^^^Slo-.
30
aggressiv
"^^^r^^2p--30
6,5-AO
1* 2 +
2 *
50
I
5
Fig.
95
Kalkhochalpen
(drip from stalactite)
\v^V
6,5-AO
in den osterreichischen
100
I
10
5:
150
I
15
1 Mendips:
2 Central
200
I
20
_[[[I
250
I
25
400
300
350
I_I_I_I
30
35
40
450 m9
CaC?3/l
45?fH
streams and risings
Runding
S. Pennines
Peak District,
Thus a brief review of the results now coming
to light suggest that temperature is not a major
factor in the dissolution of limestones. There is
almost invariably a correlation between the log. of
the discharge and the calcium hardness of waters;
despite thismaximum chemical denudation ismost
likely to occur at or near maximum discharge, due
to the large volumes of water involved. Recent
work
factors (litho
suggests that non-climatic
logy and structure of the limestones, depth and
length of time of percolation) more than compen
sate for any variation due to temperature. Further
more, the importance of soil C02 as a result of a
vegetation cover has been completely ignored in
hypotheses based solely on temperature variations.
Such a situation has been for many years recog
nized by geographers and geologists ?
long before
KALKABTRAGUNGSMESSUNGEN
6'?
5P
I_I
5
0
Fig.
1PP
10
15P
I
15
200
I
20
250
I
25
300
I
30
350
I
35
400
I
40
.
450 m9
I CaC?3/L
45?fH
6: New
South Wales
(Australia)
1 Coolaman
Plain
(1330 m. above S. L., 1200 mm
mean
C.
annual temp.)
12?
rainfall,
2 Jenolan
S. L., 800 mm rainfall,
(800 m. above
16? C. mean annual temp.)
(from observations
by J.N. Jennings)
the somewhat misleading
attempts which have
been made recently to over-simplify a very com
plex problem. It also illustrated the need to tackle
the problem in a completely different manner.
References
en Terrain
Ann.
"Erosion
Calcaire",
J.
68e annee, pp. 97?116.
Geogr.,
2. Douglas,
I. 1962. "An Evaluation
of some Techniques
used in the Study of landforms with special reference to
Limestone
Areas".
of Oxford.
Unpublished
thesis, Univ.
3. Kendall,
P. F. and Wroot,
H. E. 1924. "The Geology
of Yorkshire",
page 943.
4. Piggott,
on "Denudation
D.
1963. Symposium
in Lime
stone Regions";
Soc. Unpublished.
Royal Geog.
5. Ingle Smith, D. and Mead,
D. G. 1962. "The solution of
with special reference toMendip.
Proc. Uni
Limestone",
Soc. Vol.
9, No.
versity of Bristol Spelaeological
3, pp.
188?211.
1. Corbel,
1959.
IN DEN OSTERREICHISCHEN
KALKHOCHALPEN
Mit 4 Abbildungen und 2 Tabellen
Fridtjof
Eines der wesentlichsten Merkmale
eines Karst
seiner
gebietes ist die dauernde Umgestaltung
Oberflache
durch die karbonatlosende Wirkung
Diese kontinu
C02-haltiger Niederschlagswasser.
vor sich ge
ierliche, auch unter Bodenbedeckung
hende Veranderung der Gesteinsoberflache
schafft
Bauer
laufend neue Voraussetzungen
fiir die Entwick
lung der iiberlagernden Boden und der Struktur
der Vegetation, wie auch fiir Mikroklima
und
Oberflachenwasserhaushalt.
Die Frage nach der
des Karbonatgesteinsabtrages
Geschwindigkeit
mufi daher im Rahmen eines Karstforschungspro