More evidence against so-called paleokarst
by John Woodmorappe
Abstract
A long-accepted mid-Carboniferous ‘paleokarst’ in the western United
States fails several tests for subaerial exposure at the time of
‘karstification.’ The evidence for a onetime erosional surface is
ambiguous. Other geologic evidences, notably indicators of
sediment cave-in, demonstrate that the overlying sedimentary rock was
already present when solution features such as vugs, sinkholes, and
intra-formational breccias formed. And, far from requiring long
periods of time to form, the alleged karstic features formed rapidly,
within the entire ‘stack’ of sedimentary rocks, as a result of
deep-seated hydrothermal action during and after the Flood. Thus,
this alleged indicator of long periods of geologic time turns into
evidence for extensive geologic catastrophism during the Flood.
Paleokarst
refers to features within a rock that supposedly indicate a protracted
period of surface and near-surface erosion that occurred before the
next layer of sediment was deposited. It is obviously
incompatible with a global Flood. Silvestru1
has comprehensively critiqued paleokarst using European examples.
He showed that true karstic features, such as deeply-emplaced caves,
are invariably absent from so-called paleokarst. Moreover, as
used by certain uniformitarian geologists, paleokarst is an amorphous
term associated with a particular mineral paragenesis. However,
to geographers the word paleokarst connotes a landform.
Furthermore, uniformitarians often infer an ancient surface of
prolonged exposure solely from petrographic and isotopic data, without
any collateral geologic evidence of subaerial exposure!2
Figure 1. Generalized sketch of the geology of the Madison Limestone and Amsden Formation in north-central Wyoming, USA (from Sando).5
Click here to view full-size image.
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One outstanding example from the Rocky Mountains of west-central USA has
been long claimed to strongly demonstrate a paleokarstic surface.
However, certain uniformitarian geologists are now challenging this
claim. This so-called paleokarst occurs near the mid-Carboniferous3
(the Visean/Namurian boundary) of several US States. It should
also be noted that, according to sequence stratigraphy, the
mid-Carboniferous is the boundary4
between the Kaskaskia and the Absokora cycles. Therefore, a
challenge to subaerial exposure here also challenges the entire
sequence-stratigraphic concept.
Description of alleged paleokarst
Referring to my Figure 1, taken from Fig. 1 of Sando,5 the following statements summarize the orthodox uniformitarian interpretation:
‘A
karst topography developed on top of Madison Group sediments near the
close of Mississippian [Lower Carboniferous] time, and solution
phenomena such as sinkholes and “bedding plane solution cavities”, here
referred to as bedding cavities, were abundant.
Subsequently these cavities were filled with sandstone and shale of the
Amsden Formation (Pennsylvanian) [Upper Carboniferous]. Bedded
sandstones fill the numerous bedding cavities, giving the illusion that
the basal sandstone of the Amsden has a sequence of Mississippian
carbonate beds within it, beds which in reality are the uppermost
strata of the Madison Group ... . The filled bedding cavities may
extend from several feet to hundreds of feet ... . This situation
has led some workers to assign erroneously a Mississippian age to the
basal part of the Amsden Formation.’6
Note
from Figure 1 that there are two layers of breccias in the Madison
Limestone: the lower solution zone and the upper solution zone.
However, only the uppermost part of the Madison Limestone is supposed
to be the paleokarst surface (more on this later). The overlying
Amsden Formation is supposed to include the sedimentary deposits of the
marine transgression that finally covered the long-exposed paleokarst
surface.
Note also that, within the Madison
Limestone, the Darwin sandstone member of the Amsden Formation not only
fills sinkholes, but also vugs (solution cavities). However, one
should not suppose from Figure 1 that the Madison Limestone is
perforated in three dimensions like Swiss cheese. Rather, the
vugs within the limestone are not generally interconnected.
If
the paleokarstic interpretation is to be credible scientifically, the
claim must pass unambiguous tests. First, it must be shown that
the overlying sedimentary lithologies (in this case, the Amsden
Formation) were necessarily deposited after the solution
zones, sinkholes, and vug-filled texture formed within the underlying
carbonate (the Madison Limestone). Second, and as a corollary,
the solution cavities of the alleged karstic carbonate horizon must
clearly point to post-solutional infilling through sedimentary
processes (i.e. the marine transgression), rather than post-solutional
infilling through secondary processes such as cave-ins of existing
overburden (sediment or sedimentary rock). Finally, the alleged
karstic horizon must be uniquely explicable by protracted, near-surface processes involving water of strictly meteorological origin. As discussed below, the alleged ‘paleokarst’ fails all three tests.
Stratigraphic evidences against a paleokarst interpretation
Silvestru
pointed out that, in large areas of the Swiss Alps, carbonates of
mid-upper Cretaceous age are overlain by mid-Tertiary beds, implying a
hiatus of tens of millions of years according to standard
uniformitarian thinking.7
Yet the Cretaceous carbonates show no hint of paleo-relief, let alone a
karstic surface. Ironically, the opposite situation exists in the
US Rockies. The alleged paleokarst exists on a surface where the
inferred period of ‘missing’ time is only 2–3 million years.
Surprisingly, Bridges8 suggests this time is too short to form a paleokarst! Again, the plasticity of uniformitarian thinking is impressive.
For
the Madison/Amsden contact (Figure 1) to have a chance of being
paleokarstic, the contact must first be an unconformity. The
equivalent contact in Wyoming contains arches and other irregularities,9 which argue against an unconformable contact, and prove that the overburden was already there. This demonstrates that the contact was corroded, not by near-surface karstic solution, but by deep-subsurface solution of Madison-equivalent limestones.
Rounded limestone clasts within the solution deposits10 at the top of the Madison formation (Figure 1) are often cited as evidence for a onetime erosional surface. However, subsurface solutions can generate rounded limestone clasts, as demonstrated elsewhere by in-situ limestone wall-rock fragments that are rounded.11
Hence, rounded limestone clasts are not, on their own, evidence for a
penecontemporaneous subaerial erosional surface. Also there are
numerous chert pebbles in the regionally-equivalent ‘erosional’
surface, but these are angular, not rounded as we would expect if the
unconformity had existed for a long time. Moreover, they are not
bedded, and some chert pebbles are incrusted, suggesting growth in
place.8
All this argues that the chert is a secondary product of subsurface
solution, not the result of sedimentary water transport along a
mythical erosional surface, let alone a paleokarstic one.
It
is also claimed that the upper breccia (Figure 1) was formed by karstic
processes, thus supporting the paleokarst interpretation.
However, the thickness of the breccia layer is too regular for it to
have been formed concurrently by karstic process.12 We would expect a breccia of karstic origin, especially one that covers an area as large as 250 km2, to display more thickening and thinning.
Sedimentary evidences against a paleokarst interpretation
Whenever
we think of caves we think of stalagmites and stalactites. Yet,
not only do the ‘caves’ (actually, vugs) within the Madison Limestone
lack these features, but they also lack flowstone and dripstone
deposits.13 This itself does not disprove a paleokarst interpretation, as some modern caves also lack these deposits.14 But it is significant that this major evidence for paleokarst is missing.
The
scale of the alleged paleokarstic features also bears comment.
Like the alleged European ‘paleokarst’ discussed by Silvestru,7
the North American mid-Carboniferous features discussed here are
essentially surficial. Thus, they bear little resemblance to the
deep channels and huge caverns encountered in the genuine paleokarstic
systems found today.
An examination of the
overlying sedimentary structures can help us determine if a surface was
exposed to weathering for a long time before the overlying sediment was
deposited. For a weathering surface, or paleokarst, the overlying
sedimentary cover must have been absent while the karst features were
forming. It’s like detective work, like finding snow covering a
deep depression in the ground and trying to determine whether the
depression slumped before or after the snowfall. Clearly, if the
depression existed before the snowfall (like a paleokarst), the snow
should have a gently-rolling contact at the edges of the
depression. In addition, the snow surface should gently sag
inward as it blankets the hollow and the surrounding area.
Conversely, if the snowfall occurred first, the ground must have
caved-in later. This would have disturbed the pre-existing snow
layer, and may even have caused the snow surface to cave-in.
Instead of a gently-rolling surface, the snow surface would show abrupt
changes in its ‘stratigraphy,’ indicative of collapsing into the
hollow. The latter would also include features such as sharp
bends at the edges of the hole, cracking and ‘downfaulting’ of the snow
(especially if it was partly frozen), and possibly a chaotic mixture of
snow within the hole itself.
There are many
solution cavities in the Madison Limestone (and regional equivalents)
where the fill-in material clearly has caved-in or collapsed.
Such evidence does not support the concept of a paleokarst, that the
cavities were already present before the overlying sediment and fill
were deposited from a transgressing sea. In some places, notably
Wyoming, the overlying Upper Carboniferous sedimentary rock has
downfaulted and collapsed into a solution cavity in the underlying
Lower Carboniferous carbonate.15 In another example, sedimentary material above the Madison-Limestone-regional-equivalent is downfaulted into a sinkhole.16
The final blow against the idea of karstification is the presence of
sandstone boulders from the overlying Amsden Formation within the Madison-Limestone solution breccia.23 Clearly, the Amsden Formation was already in place before the breccia formed in the underlying limestone.
Another
alleged ‘paleokarst,’ within the Silurian dolomites of northeastern
Illinois, USA, is similarly discredited because its sedimentary fill
shows evidence of downbending, not deposition. Abrupt changes,
over short distances, in the dips and strikes of infilling
Carboniferous shales within cavities in Silurian dolomites,16 demonstrate that the overlying Carboniferous sediments were already present when
the cavities formed. Far from showing a depositional contact, the
sandstone slabs downbend and stretch to fit over and into the cavities
in the Silurian.17
Furthermore, the Carboniferous coals are contorted in ways that are
irreconcilable with the premise that they were deposited by sedimentary
processes over pre-existing karstic cavities in the Silurian dolomite.18
Another way of confirming significant post-depositional sediment movement is by the presence of slickensides and slickolites.19 Slickensides indicate tectonic movement, or extensive vertical compaction of sediment.20
Slickolites, which are closely related to slickensides, are indicators
of vertical sedimentary movement. Slickolites are especially
prominent in the Carboniferous material that fills the Silurian
‘paleokarst’ solution cavities21
of northeastern Illinois, USA, showing that the material
caved-in. In like manner, slickolites frequently occur within the
material that fills the mid-Carboniferous Madison Limestone cavities,
proving that the fill material caved-in and was not water deposited.22 Indeed, the evidence indicates that there was considerable downward sliding (caving-in) of the overburden into the solution cavities and sinkholes.16 For the Amsden Formation (Figure 1) and regional equivalents to move downward en masse, they must have obviously already existed
as overburden, when the cavities and sinkholes were forming
underneath. This alone rules out a surface-weathering, karstic
explanation for the solution features in the Madison Limestone (and
regional equivalents).
To preserve the paleokarst
interpretation, a uniformitarian might claim that a karstic surface
formed in the mid-Carboniferous but that the solution cavities were
filled with pressurized water from below. He may argue that the
pressure of the water prevented the cavities from collapsing until a
large thickness of Upper Carboniferous sediment accumulated on
top. Such an invention would be totally ad hoc, lacking
any independent evidence of a local karstic aquifer, much less the
‘plumbing system’ needed to supply and maintain the pressurized
water. More importantly, the claim does not deal with the central
problem. If the cavities really existed as an erosional surface
when the overlying sediment was being deposited, they would have filled
with clouds of fine sediment from the transgressing Upper Carboniferous
sea. Thus, the cavities (as discussed earlier) would be largely,
if not completely, filled with sediment exhibiting a gentle,
depositional contact. And the sediment filling the cavities would
have prevented the overburden from collapsing and caving-in.
But
what if the cavities were covered by a ‘roof’ of carbonate rock at the
time of the Upper-Carboniferous transgression. It could be
claimed that a rock ‘roof’ would initially prevent the sediment from
filling the cavities. However, this idea only creates more
problems. The pressure of the subterranean waters would need to
follow a very delicate balance. The pressure would have to be
high enough to prevent the postulated roof collapsing under the weight
of the ever-encroaching Upper Carboniferous sea, yet not so high that
it pops the roof off the karstic cavities. Moreover, this
delicate balance of pressure would have to be maintained over the
millions of years needed for an appreciable amount of Upper
Carboniferous sediment to accumulate and lithify, all the while keeping
pace with the increasing weight of overburden. Only when all
these processes were complete could the ‘roof’ and overlying
sedimentary rock collapse.
As if all this was not
enough, as noted earlier, the presence of Amsden rock within
Madison-Limestone breccias proves that overlying Amsden Formation was
already in place when the breccia formed. Even if a paleokarstic
explanation could be rescued by a series of complex, secondary
hypotheses, the prima facie evidence nevertheless continues to
favour a nonkarstic explanation. At very least, the evidence most
definitely does not require a paleokarstic explanation.
It
is interesting to note that other evidences from the Mid-Carboniferous
that could potentially support a paleokarst interpretation have been
recently discredited. For example, from the southwestern USA:
‘The Pennsylvanian [Upper Carboniferous] Molas Formation has long been considered as a terra rossa
(residual) paleosol that developed above a paleokarst surface above the
Mississippian [Lower Carboniferous] Leadville Limestone. A
detailed field, SEM/EDS, XRD, and petrography study shows that this
classic interpretation is untenable.’23
The
erstwhile paleosol, an obvious long-time indicator, is now considered a
massive aeolian siltstone (loessite). In like fashion, the
characteristic reddening of the Molas Formation, often attributed in
the past to long-term near-surface weathering, is now regarded as a
diagenetic feature.24
Geologic alternatives to paleokarst
Silvestru25
explains that aqueous solutions can exist at considerable depths
because of hydrothermal activity. Consequently, karst-like
features can form at great depth. They do not require a subaerial
erosional surface to be exposed for long periods to allow meteoric
water to percolate through and enlarge the joints within the carbonate
rocks. And hydrothermal activity hardly exhausts non-karstic
explanations for supposedly paleokarstic features. For instance,
cavities and breccias can be formed at depth in sediments by bubbles of
gas rising from below.26
Here,
however, I focus exclusively on hydrothermal explanations. It is
believed that such processes require a temperature of only 150°C (quite
cool by geologic standards) to not only dissolve limestone, but also
large volumes of sandstone.27
In some locations, notably Colorado, USA, the dissolution observed in
mid-Carboniferous lithologies is closely correlated to the presence of
ore deposits.28
This has prompted the suggestion that mineral-bearing hydrothermal
solutions utilised the existing permeability generated by previous
karstic activity, enlarging the openings while depositing the ore
material. But this explanation assumes that the previous karstic
activity really existed. In fact, the hydrothermal explanation is
perfectly adequate to explain the morphology of the limestone horizons
without adding alleged ‘paleokarst’ processes.
Perhaps
ironically, a double standard has long been followed relative to the
two solution breccias (Figure 1) within the Madison Limestone.
For decades, while the paleokarst explanation for the upper breccia
reigned unchallenged, some uniformitarian investigators concluded that
the lower breccia formed in hydrothermal processes related to the
Tertiary Laramide orogeny (see below). Thus, the lower breccia
considerably postdated the deposition of both the Madison and the
Amsden. However, the only recognisable differences between the
breccias involve the clay mineralogy,29
and these do not compel a paleokarstic origin for the upper
breccia. Rather, the origin of both breccias can be explained by
the same hydrothermal activity, which affected both the upper
and the lower breccias of the Madison Limestone. The differences
in clay mineralogy are readily explained by each layer being affected
for a different duration and intensity.
The hydrothermal action that formed the karst-like features, uniformitarians attribute to the Tertiary Laramide orogeny.30
This is solely because that orogeny is the only major geological event
that locally postdates both the ‘karst’ and the overlying
sediments. However, freed from uniformitarian thinking, Flood
geologists realize that the hydrothermal action could have occurred anytime
after the Madison-Amsden (and equivalents) were deposited. In a
young-earth, global-Flood context, the hydrothermal action probably
occurred soon after the sediments were deposited by the Flood and for
some years afterwards.
The deep-seated
hydrothermal explanation is more understandable from a Diluvial context
than a uniformitarian one. According to the latter, mountains are
built and magmas are generated and cooled over millions of years.
Thus, hydrothermal activity would be less likely because any heat
generated would tend to dissipate instead of accumulating over a large
geographic area. By contrast, in a Diluvialist context, processes
ranging from the rapid melting of continental crust31 to the rapid cooling of intruded magmas32
would produce great quantities of heat all at once. Vigorous
hydrothermal activity would occur as a result of the enormous volumes
of hot subterranean water produced. Consequently, ‘paleokarst’
would have been produced well below the land surface on a
subcontinental scale within pre-existing layers of thick sedimentary
rocks.
Conclusions
Even within
uniformitarian thinking, the rejection of paleokarst explanations in
favour of giant, deep-seated hydrothermal systems is nothing short of
revolutionary:
‘I am convinced that we have not been thinking big enough,
and conclude that this breccia lense [sic] is part of a Tertiary
heated-water subsurface-plumbing system ... (emphasis added).’12
‘The primary conclusion is that Laramide-Tertiary subsurface solution from heated subsurface waters is an important geologic phenomenon whose scope vastly exceeds present geologic thinking.
Many low-grade metamorphic phenomena in sedimentary rocks have gone
unnoticed or been misinterpreted. It is suggested that much of
the chert in Paleozoic rocks, which we have taken for granted to be
Paleozoic chert, may be Tertiary chert. In my opinion, the late
Mississippian [Mid-Carboniferous] karst story in the Rocky Mountains is
completely fallacious (emphasis added).’33
Once
again, a ‘self-evident’ indicator of long periods of geologic time
turns out to be more suited to an alternative interpretation, one that
is compatible with a young-earth global-Flood model. Instead of
being paleokarstic in origin, the structures within carbonates formed after
the overlying sediment was deposited, and they furthermore bear witness
to geographically extensive deep-crustal upwellings of hot-water
solutions. Consequently, not only does the claim for
long-duration earth-surface processes dissolve (pardon the pun), but,
ironically, in a jujitsu turnaround, the claim self-converts into
evidence for extensive geologic catastrophism during the Flood.
John Woodmorappe
has an M.A. in geology and a B.A. in biology, from a midwestern US
state university. He is a science educator by profession.
He is the author of Studies in Flood Geology, Noah’s Ark: A Feasibility Study, and the recently released The Mythology of Modern Dating Methods.
References and notes
- Silvestru, E., Paleokarst—a riddle inside confusion, CEN Tech. J. 14(3):100–108, 2000. Return to text.
- Hunter et al., Testing for subaerial exposure at five Upper Ordovician sequence boundaries, Nashville Dome, Tennessee, Geological Society of America Abstracts with Programs 31(7):A–290, 1999. Return to text.
- In
this work, I use international stratigraphic terms (e.g. Carboniferous,
Namurian), not North American ones (e.g. Mississippian, Pennsylvanian,
Chesterian) used by the authors of the geologic papers I cite. Return to text.
- Leighton,
M.W. and Kolata, D.R., Selected interior cratonic basins and their
place in the scheme of global tectonics; in: Leighton, et al., (Eds), Interior Cratonic Basins, AAPG Memoir 51, p. 732, 1990. Return to text.
- Sando, W.J., Ancient solution phenomena in the Madison Limestone (Mississippian) of north-central Wyoming, J. Research of the United States Geological Survey 2(2):134, 1974. Return to text.
- Foster, N.H., Stratigraphic leak, Bull. American Association of Petroleum Geologists 50(12):2604–2605, 1966. Return to text.
- Silvestru, Ref. 1, p. 104. Return to text.
- Bridges,
L.W.D., Rocky Mountain Laramide-Tertiary subsurface solution vs.
Paleozoic karst in Mississippian carbonates; in: Reid, S.G. and Foote,
D.J. (Eds), Thirty-Third Annual Field Conference—1982 Wyoming Geological Association Guidebook, p. 257, 1982. Return to text.
- Bridges, L.W.D., Ames Depression, Oklahoma: domal collapse and later subsurface solution, Oklahoma Geological Survey Circular 100:164–165, 1997. Return to text.
- Bridges, Ref. 8, p. 251. Return to text.
- Bretz, J.H., Solution cavities in the Joliet Limestone of northeastern Illinois, J. Geology 48(4):362, 1940. Return to text.
- Bridges, Ref. 8, p. 260. Return to text.
- Sando, Ref. 5, p. 135. Return to text.
- In
order for flowstone and dripstone to form in caves, the cave must be
above the water table. When that happens, carbonate-rich waters
can enter the cave, through tiny to large openings, and deposit their
load in the free-air environment of the cave. Return to text.
- Bridges, Ref. 9, p. 165. Return to text.
- Bretz,
Ref. 11, pp. 368, 371. The dips are recognizably much too steep
to have originated from deposition of the Carboniferous sediments into
already-existing Silurian surficial karstic features. Return to text.
- Bretz, Ref. 11, p. 377. Return to text.
- Bretz,
Ref. 11, p. 373. Not surprisingly, Bretz (Ref. 11, p. 384)
rejects the paleokarst explanation for the Silurian dolomites of
northeastern Illinois, USA. Return to text.
- Slickolites
are striations found on rock surfaces, consisting of closely crowded
grooves and ridges along vertical or nearly vertical planes, which
roughly parallel the cavity walls. They are unequivocally
indicative of considerable subsidence adjustments. Return to text.
- Woodmorappe, J. , Studies in Flood Geology,
Institute for Creation Research, El Cajon, p. 216, 1999. For
example, the so-called underclays in coal-bearing cyclothems often show
slickensides as a result of extensive compaction which followed
deposition. Return to text.
- Bretz, Ref. 11, pp. 352–354, 379. Return to text.
- Bridges, Ref. 8, pp. 254–255. Return to text.
- Evans,
J.E. and Reed, J.M., Reinterpretation of the Pennsylvanian Molas
Formation (San Juan Basin) as a loessite, not as a terra rossa
paleosol, Geological Society of America Abstracts with Programs 31(7):A–160, 1999. Return to text.
- Reed,
J.M. and Evans, J.E., Diagenetic reddening of the Molas Formation (San
Juan Basin): infiltration features in a Pennsylvanian loessite, Geological Society of America Abstracts with Programs 31(7):A–281, 1999. Return to text.
- Silvestru, Ref. 1, p. 103. Return to text.
- Silvestru, E. , Bubbles of surprise, TJ 15(2):89–93, 2001. Return to text.
- Bridges, L.W.D., Tertiary subsurface solution versus Paleozoic karst solution, Guernsey, Wyoming, Geological Society of America Centennial Field Guide—Rocky Mountain Section, p. 205, 1987. Return to text.
- Lovering et al., Ore deposits of the Gilman District, Eagle County, Colorado, United States Geological Survey Professional Paper 1017, p. 32, 1978. Return to text.
- Bridges,
Ref. 8, p. 253. The upper solution breccia, attributed to
paleokarst, contains kaolinite as the chief clay mineral. The
lower solution breccia, not attributed to paleokarst, has illite as the
chief clay mineral. However, kaolinite is a
hydrothermal-alteration product of illite. Therefore, the longer
and more intense the hydrothermal processes are, the more kaolinite
there will be at the expense of illite. Return to text.
- Bridges, Ref. 9, p. 164. Return to text.
- Woodmorappe, J., The rapid formation of granitic rocks: more evidence, TJ 15(2):122–125, 2001. Return to text.
- Snelling, A.A. and Woodmorappe, J., The cooling of thick igneous bodies on a young Earth; in: Walsh, R.E., (Ed.), Proceedings of the Fourth International Conference on Creationism, Technical Volume, Creation Science Fellowship, Pittsburgh, pp. 527–545, 1998. For a popular-level summary of this research, see Woodmorappe, J., Granites ... they didn’t need millions of years of cooling, Creation 21(1):42–44, 1999. Return to text.
- Bridges, Ref. 8, p. 264. Return to text.
Editors’ note
Original manuscript was received on 17 August 2001. It is worth noting
that the papers dealing with alleged paleokarsts by Woodmorappe and Silvestru in this issue of TJ
were prepared independently of each other. Any similarities
between the concepts expressed are due to creationist thinking
converging upon a solution to an alleged problem.
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 First published:
TJ 15(3):100–104
December 2001
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More evidence against so-called paleokarst
by John Woodmorappe
Abstract
A long-accepted mid-Carboniferous ‘paleokarst’ in the western United
States fails several tests for subaerial exposure at the time of
‘karstification.’ The evidence for a onetime erosional surface is
ambiguous. Other geologic evidences, notably indicators of
sediment cave-in, demonstrate that the overlying sedimentary rock was
already present when solution features such as vugs, sinkholes, and
intra-formational breccias formed. And, far from requiring long
periods of time to form, the alleged karstic features formed rapidly,
within the entire ‘stack’ of sedimentary rocks, as a result of
deep-seated hydrothermal action during and after the Flood. Thus,
this alleged indicator of long periods of geologic time turns into
evidence for extensive geologic catastrophism during the Flood.
Paleokarst
refers to features within a rock that supposedly indicate a protracted
period of surface and near-surface erosion that occurred before the
next layer of sediment was deposited. It is obviously
incompatible with a global Flood. Silvestru1
has comprehensively critiqued paleokarst using European examples.
He showed that true karstic features, such as deeply-emplaced caves,
are invariably absent from so-called paleokarst. Moreover, as
used by certain uniformitarian geologists, paleokarst is an amorphous
term associated with a particular mineral paragenesis. However,
to geographers the word paleokarst connotes a landform.
Furthermore, uniformitarians often infer an ancient surface of
prolonged exposure solely from petrographic and isotopic data, without
any collateral geologic evidence of subaerial exposure!2
Figure 1. Generalized sketch of the geology of the Madison Limestone and Amsden Formation in north-central Wyoming, USA (from Sando).5
Click here to view full-size image.
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One outstanding example from the Rocky Mountains of west-central USA has
been long claimed to strongly demonstrate a paleokarstic surface.
However, certain uniformitarian geologists are now challenging this
claim. This so-called paleokarst occurs near the mid-Carboniferous3
(the Visean/Namurian boundary) of several US States. It should
also be noted that, according to sequence stratigraphy, the
mid-Carboniferous is the boundary4
between the Kaskaskia and the Absokora cycles. Therefore, a
challenge to subaerial exposure here also challenges the entire
sequence-stratigraphic concept.
Description of alleged paleokarst
Referring to my Figure 1, taken from Fig. 1 of Sando,5 the following statements summarize the orthodox uniformitarian interpretation:
‘A
karst topography developed on top of Madison Group sediments near the
close of Mississippian [Lower Carboniferous] time, and solution
phenomena such as sinkholes and “bedding plane solution cavities”, here
referred to as bedding cavities, were abundant.
Subsequently these cavities were filled with sandstone and shale of the
Amsden Formation (Pennsylvanian) [Upper Carboniferous]. Bedded
sandstones fill the numerous bedding cavities, giving the illusion that
the basal sandstone of the Amsden has a sequence of Mississippian
carbonate beds within it, beds which in reality are the uppermost
strata of the Madison Group ... . The filled bedding cavities may
extend from several feet to hundreds of feet ... . This situation
has led some workers to assign erroneously a Mississippian age to the
basal part of the Amsden Formation.’6
Note
from Figure 1 that there are two layers of breccias in the Madison
Limestone: the lower solution zone and the upper solution zone.
However, only the uppermost part of the Madison Limestone is supposed
to be the paleokarst surface (more on this later). The overlying
Amsden Formation is supposed to include the sedimentary deposits of the
marine transgression that finally covered the long-exposed paleokarst
surface.
Note also that, within the Madison
Limestone, the Darwin sandstone member of the Amsden Formation not only
fills sinkholes, but also vugs (solution cavities). However, one
should not suppose from Figure 1 that the Madison Limestone is
perforated in three dimensions like Swiss cheese. Rather, the
vugs within the limestone are not generally interconnected.
If
the paleokarstic interpretation is to be credible scientifically, the
claim must pass unambiguous tests. First, it must be shown that
the overlying sedimentary lithologies (in this case, the Amsden
Formation) were necessarily deposited after the solution
zones, sinkholes, and vug-filled texture formed within the underlying
carbonate (the Madison Limestone). Second, and as a corollary,
the solution cavities of the alleged karstic carbonate horizon must
clearly point to post-solutional infilling through sedimentary
processes (i.e. the marine transgression), rather than post-solutional
infilling through secondary processes such as cave-ins of existing
overburden (sediment or sedimentary rock). Finally, the alleged
karstic horizon must be uniquely explicable by protracted, near-surface processes involving water of strictly meteorological origin. As discussed below, the alleged ‘paleokarst’ fails all three tests.
Stratigraphic evidences against a paleokarst interpretation
Silvestru
pointed out that, in large areas of the Swiss Alps, carbonates of
mid-upper Cretaceous age are overlain by mid-Tertiary beds, implying a
hiatus of tens of millions of years according to standard
uniformitarian thinking.7
Yet the Cretaceous carbonates show no hint of paleo-relief, let alone a
karstic surface. Ironically, the opposite situation exists in the
US Rockies. The alleged paleokarst exists on a surface where the
inferred period of ‘missing’ time is only 2–3 million years.
Surprisingly, Bridges8 suggests this time is too short to form a paleokarst! Again, the plasticity of uniformitarian thinking is impressive.
For
the Madison/Amsden contact (Figure 1) to have a chance of being
paleokarstic, the contact must first be an unconformity. The
equivalent contact in Wyoming contains arches and other irregularities,9 which argue against an unconformable contact, and prove that the overburden was already there. This demonstrates that the contact was corroded, not by near-surface karstic solution, but by deep-subsurface solution of Madison-equivalent limestones.
Rounded limestone clasts within the solution deposits10 at the top of the Madison formation (Figure 1) are often cited as evidence for a onetime erosional surface. However, subsurface solutions can generate rounded limestone clasts, as demonstrated elsewhere by in-situ limestone wall-rock fragments that are rounded.11
Hence, rounded limestone clasts are not, on their own, evidence for a
penecontemporaneous subaerial erosional surface. Also there are
numerous chert pebbles in the regionally-equivalent ‘erosional’
surface, but these are angular, not rounded as we would expect if the
unconformity had existed for a long time. Moreover, they are not
bedded, and some chert pebbles are incrusted, suggesting growth in
place.8
All this argues that the chert is a secondary product of subsurface
solution, not the result of sedimentary water transport along a
mythical erosional surface, let alone a paleokarstic one.
It
is also claimed that the upper breccia (Figure 1) was formed by karstic
processes, thus supporting the paleokarst interpretation.
However, the thickness of the breccia layer is too regular for it to
have been formed concurrently by karstic process.12 We would expect a breccia of karstic origin, especially one that covers an area as large as 250 km2, to display more thickening and thinning.
Sedimentary evidences against a paleokarst interpretation
Whenever
we think of caves we think of stalagmites and stalactites. Yet,
not only do the ‘caves’ (actually, vugs) within the Madison Limestone
lack these features, but they also lack flowstone and dripstone
deposits.13 This itself does not disprove a paleokarst interpretation, as some modern caves also lack these deposits.14 But it is significant that this major evidence for paleokarst is missing.
The
scale of the alleged paleokarstic features also bears comment.
Like the alleged European ‘paleokarst’ discussed by Silvestru,7
the North American mid-Carboniferous features discussed here are
essentially surficial. Thus, they bear little resemblance to the
deep channels and huge caverns encountered in the genuine paleokarstic
systems found today.
An examination of the
overlying sedimentary structures can help us determine if a surface was
exposed to weathering for a long time before the overlying sediment was
deposited. For a weathering surface, or paleokarst, the overlying
sedimentary cover must have been absent while the karst features were
forming. It’s like detective work, like finding snow covering a
deep depression in the ground and trying to determine whether the
depression slumped before or after the snowfall. Clearly, if the
depression existed before the snowfall (like a paleokarst), the snow
should have a gently-rolling contact at the edges of the
depression. In addition, the snow surface should gently sag
inward as it blankets the hollow and the surrounding area.
Conversely, if the snowfall occurred first, the ground must have
caved-in later. This would have disturbed the pre-existing snow
layer, and may even have caused the snow surface to cave-in.
Instead of a gently-rolling surface, the snow surface would show abrupt
changes in its ‘stratigraphy,’ indicative of collapsing into the
hollow. The latter would also include features such as sharp
bends at the edges of the hole, cracking and ‘downfaulting’ of the snow
(especially if it was partly frozen), and possibly a chaotic mixture of
snow within the hole itself.
There are many
solution cavities in the Madison Limestone (and regional equivalents)
where the fill-in material clearly has caved-in or collapsed.
Such evidence does not support the concept of a paleokarst, that the
cavities were already present before the overlying sediment and fill
were deposited from a transgressing sea. In some places, notably
Wyoming, the overlying Upper Carboniferous sedimentary rock has
downfaulted and collapsed into a solution cavity in the underlying
Lower Carboniferous carbonate.15 In another example, sedimentary material above the Madison-Limestone-regional-equivalent is downfaulted into a sinkhole.16
The final blow against the idea of karstification is the presence of
sandstone boulders from the overlying Amsden Formation within the Madison-Limestone solution breccia.23 Clearly, the Amsden Formation was already in place before the breccia formed in the underlying limestone.
Another
alleged ‘paleokarst,’ within the Silurian dolomites of northeastern
Illinois, USA, is similarly discredited because its sedimentary fill
shows evidence of downbending, not deposition. Abrupt changes,
over short distances, in the dips and strikes of infilling
Carboniferous shales within cavities in Silurian dolomites,16 demonstrate that the overlying Carboniferous sediments were already present when
the cavities formed. Far from showing a depositional contact, the
sandstone slabs downbend and stretch to fit over and into the cavities
in the Silurian.17
Furthermore, the Carboniferous coals are contorted in ways that are
irreconcilable with the premise that they were deposited by sedimentary
processes over pre-existing karstic cavities in the Silurian dolomite.18
Another way of confirming significant post-depositional sediment movement is by the presence of slickensides and slickolites.19 Slickensides indicate tectonic movement, or extensive vertical compaction of sediment.20
Slickolites, which are closely related to slickensides, are indicators
of vertical sedimentary movement. Slickolites are especially
prominent in the Carboniferous material that fills the Silurian
‘paleokarst’ solution cavities21
of northeastern Illinois, USA, showing that the material
caved-in. In like manner, slickolites frequently occur within the
material that fills the mid-Carboniferous Madison Limestone cavities,
proving that the fill material caved-in and was not water deposited.22 Indeed, the evidence indicates that there was considerable downward sliding (caving-in) of the overburden into the solution cavities and sinkholes.16 For the Amsden Formation (Figure 1) and regional equivalents to move downward en masse, they must have obviously already existed
as overburden, when the cavities and sinkholes were forming
underneath. This alone rules out a surface-weathering, karstic
explanation for the solution features in the Madison Limestone (and
regional equivalents).
To preserve the paleokarst
interpretation, a uniformitarian might claim that a karstic surface
formed in the mid-Carboniferous but that the solution cavities were
filled with pressurized water from below. He may argue that the
pressure of the water prevented the cavities from collapsing until a
large thickness of Upper Carboniferous sediment accumulated on
top. Such an invention would be totally ad hoc, lacking
any independent evidence of a local karstic aquifer, much less the
‘plumbing system’ needed to supply and maintain the pressurized
water. More importantly, the claim does not deal with the central
problem. If the cavities really existed as an erosional surface
when the overlying sediment was being deposited, they would have filled
with clouds of fine sediment from the transgressing Upper Carboniferous
sea. Thus, the cavities (as discussed earlier) would be largely,
if not completely, filled with sediment exhibiting a gentle,
depositional contact. And the sediment filling the cavities would
have prevented the overburden from collapsing and caving-in.
But
what if the cavities were covered by a ‘roof’ of carbonate rock at the
time of the Upper-Carboniferous transgression. It could be
claimed that a rock ‘roof’ would initially prevent the sediment from
filling the cavities. However, this idea only creates more
problems. The pressure of the subterranean waters would need to
follow a very delicate balance. The pressure would have to be
high enough to prevent the postulated roof collapsing under the weight
of the ever-encroaching Upper Carboniferous sea, yet not so high that
it pops the roof off the karstic cavities. Moreover, this
delicate balance of pressure would have to be maintained over the
millions of years needed for an appreciable amount of Upper
Carboniferous sediment to accumulate and lithify, all the while keeping
pace with the increasing weight of overburden. Only when all
these processes were complete could the ‘roof’ and overlying
sedimentary rock collapse.
As if all this was not
enough, as noted earlier, the presence of Amsden rock within
Madison-Limestone breccias proves that overlying Amsden Formation was
already in place when the breccia formed. Even if a paleokarstic
explanation could be rescued by a series of complex, secondary
hypotheses, the prima facie evidence nevertheless continues to
favour a nonkarstic explanation. At very least, the evidence most
definitely does not require a paleokarstic explanation.
It
is interesting to note that other evidences from the Mid-Carboniferous
that could potentially support a paleokarst interpretation have been
recently discredited. For example, from the southwestern USA:
‘The Pennsylvanian [Upper Carboniferous] Molas Formation has long been considered as a terra rossa
(residual) paleosol that developed above a paleokarst surface above the
Mississippian [Lower Carboniferous] Leadville Limestone. A
detailed field, SEM/EDS, XRD, and petrography study shows that this
classic interpretation is untenable.’23
The
erstwhile paleosol, an obvious long-time indicator, is now considered a
massive aeolian siltstone (loessite). In like fashion, the
characteristic reddening of the Molas Formation, often attributed in
the past to long-term near-surface weathering, is now regarded as a
diagenetic feature.24
Geologic alternatives to paleokarst
Silvestru25
explains that aqueous solutions can exist at considerable depths
because of hydrothermal activity. Consequently, karst-like
features can form at great depth. They do not require a subaerial
erosional surface to be exposed for long periods to allow meteoric
water to percolate through and enlarge the joints within the carbonate
rocks. And hydrothermal activity hardly exhausts non-karstic
explanations for supposedly paleokarstic features. For instance,
cavities and breccias can be formed at depth in sediments by bubbles of
gas rising from below.26
Here,
however, I focus exclusively on hydrothermal explanations. It is
believed that such processes require a temperature of only 150°C (quite
cool by geologic standards) to not only dissolve limestone, but also
large volumes of sandstone.27
In some locations, notably Colorado, USA, the dissolution observed in
mid-Carboniferous lithologies is closely correlated to the presence of
ore deposits.28
This has prompted the suggestion that mineral-bearing hydrothermal
solutions utilised the existing permeability generated by previous
karstic activity, enlarging the openings while depositing the ore
material. But this explanation assumes that the previous karstic
activity really existed. In fact, the hydrothermal explanation is
perfectly adequate to explain the morphology of the limestone horizons
without adding alleged ‘paleokarst’ processes.
Perhaps
ironically, a double standard has long been followed relative to the
two solution breccias (Figure 1) within the Madison Limestone.
For decades, while the paleokarst explanation for the upper breccia
reigned unchallenged, some uniformitarian investigators concluded that
the lower breccia formed in hydrothermal processes related to the
Tertiary Laramide orogeny (see below). Thus, the lower breccia
considerably postdated the deposition of both the Madison and the
Amsden. However, the only recognisable differences between the
breccias involve the clay mineralogy,29
and these do not compel a paleokarstic origin for the upper
breccia. Rather, the origin of both breccias can be explained by
the same hydrothermal activity, which affected both the upper
and the lower breccias of the Madison Limestone. The differences
in clay mineralogy are readily explained by each layer being affected
for a different duration and intensity.
The hydrothermal action that formed the karst-like features, uniformitarians attribute to the Tertiary Laramide orogeny.30
This is solely because that orogeny is the only major geological event
that locally postdates both the ‘karst’ and the overlying
sediments. However, freed from uniformitarian thinking, Flood
geologists realize that the hydrothermal action could have occurred anytime
after the Madison-Amsden (and equivalents) were deposited. In a
young-earth, global-Flood context, the hydrothermal action probably
occurred soon after the sediments were deposited by the Flood and for
some years afterwards.
The deep-seated
hydrothermal explanation is more understandable from a Diluvial context
than a uniformitarian one. According to the latter, mountains are
built and magmas are generated and cooled over millions of years.
Thus, hydrothermal activity would be less likely because any heat
generated would tend to dissipate instead of accumulating over a large
geographic area. By contrast, in a Diluvialist context, processes
ranging from the rapid melting of continental crust31 to the rapid cooling of intruded magmas32
would produce great quantities of heat all at once. Vigorous
hydrothermal activity would occur as a result of the enormous volumes
of hot subterranean water produced. Consequently, ‘paleokarst’
would have been produced well below the land surface on a
subcontinental scale within pre-existing layers of thick sedimentary
rocks.
Conclusions
Even within
uniformitarian thinking, the rejection of paleokarst explanations in
favour of giant, deep-seated hydrothermal systems is nothing short of
revolutionary:
‘I am convinced that we have not been thinking big enough,
and conclude that this breccia lense [sic] is part of a Tertiary
heated-water subsurface-plumbing system ... (emphasis added).’12
‘The primary conclusion is that Laramide-Tertiary subsurface solution from heated subsurface waters is an important geologic phenomenon whose scope vastly exceeds present geologic thinking.
Many low-grade metamorphic phenomena in sedimentary rocks have gone
unnoticed or been misinterpreted. It is suggested that much of
the chert in Paleozoic rocks, which we have taken for granted to be
Paleozoic chert, may be Tertiary chert. In my opinion, the late
Mississippian [Mid-Carboniferous] karst story in the Rocky Mountains is
completely fallacious (emphasis added).’33
Once
again, a ‘self-evident’ indicator of long periods of geologic time
turns out to be more suited to an alternative interpretation, one that
is compatible with a young-earth global-Flood model. Instead of
being paleokarstic in origin, the structures within carbonates formed after
the overlying sediment was deposited, and they furthermore bear witness
to geographically extensive deep-crustal upwellings of hot-water
solutions. Consequently, not only does the claim for
long-duration earth-surface processes dissolve (pardon the pun), but,
ironically, in a jujitsu turnaround, the claim self-converts into
evidence for extensive geologic catastrophism during the Flood.
John Woodmorappe
has an M.A. in geology and a B.A. in biology, from a midwestern US
state university. He is a science educator by profession.
He is the author of Studies in Flood Geology, Noah’s Ark: A Feasibility Study, and the recently released The Mythology of Modern Dating Methods.
References and notes
- Silvestru, E., Paleokarst—a riddle inside confusion, CEN Tech. J. 14(3):100–108, 2000. Return to text.
- Hunter et al., Testing for subaerial exposure at five Upper Ordovician sequence boundaries, Nashville Dome, Tennessee, Geological Society of America Abstracts with Programs 31(7):A–290, 1999. Return to text.
- In
this work, I use international stratigraphic terms (e.g. Carboniferous,
Namurian), not North American ones (e.g. Mississippian, Pennsylvanian,
Chesterian) used by the authors of the geologic papers I cite. Return to text.
- Leighton,
M.W. and Kolata, D.R., Selected interior cratonic basins and their
place in the scheme of global tectonics; in: Leighton, et al., (Eds), Interior Cratonic Basins, AAPG Memoir 51, p. 732, 1990. Return to text.
- Sando, W.J., Ancient solution phenomena in the Madison Limestone (Mississippian) of north-central Wyoming, J. Research of the United States Geological Survey 2(2):134, 1974. Return to text.
- Foster, N.H., Stratigraphic leak, Bull. American Association of Petroleum Geologists 50(12):2604–2605, 1966. Return to text.
- Silvestru, Ref. 1, p. 104. Return to text.
- Bridges,
L.W.D., Rocky Mountain Laramide-Tertiary subsurface solution vs.
Paleozoic karst in Mississippian carbonates; in: Reid, S.G. and Foote,
D.J. (Eds), Thirty-Third Annual Field Conference—1982 Wyoming Geological Association Guidebook, p. 257, 1982. Return to text.
- Bridges, L.W.D., Ames Depression, Oklahoma: domal collapse and later subsurface solution, Oklahoma Geological Survey Circular 100:164–165, 1997. Return to text.
- Bridges, Ref. 8, p. 251. Return to text.
- Bretz, J.H., Solution cavities in the Joliet Limestone of northeastern Illinois, J. Geology 48(4):362, 1940. Return to text.
- Bridges, Ref. 8, p. 260. Return to text.
- Sando, Ref. 5, p. 135. Return to text.
- In
order for flowstone and dripstone to form in caves, the cave must be
above the water table. When that happens, carbonate-rich waters
can enter the cave, through tiny to large openings, and deposit their
load in the free-air environment of the cave. Return to text.
- Bridges, Ref. 9, p. 165. Return to text.
- Bretz,
Ref. 11, pp. 368, 371. The dips are recognizably much too steep
to have originated from deposition of the Carboniferous sediments into
already-existing Silurian surficial karstic features. Return to text.
- Bretz, Ref. 11, p. 377. Return to text.
- Bretz,
Ref. 11, p. 373. Not surprisingly, Bretz (Ref. 11, p. 384)
rejects the paleokarst explanation for the Silurian dolomites of
northeastern Illinois, USA. Return to text.
- Slickolites
are striations found on rock surfaces, consisting of closely crowded
grooves and ridges along vertical or nearly vertical planes, which
roughly parallel the cavity walls. They are unequivocally
indicative of considerable subsidence adjustments. Return to text.
- Woodmorappe, J. , Studies in Flood Geology,
Institute for Creation Research, El Cajon, p. 216, 1999. For
example, the so-called underclays in coal-bearing cyclothems often show
slickensides as a result of extensive compaction which followed
deposition. Return to text.
- Bretz, Ref. 11, pp. 352–354, 379. Return to text.
- Bridges, Ref. 8, pp. 254–255. Return to text.
- Evans,
J.E. and Reed, J.M., Reinterpretation of the Pennsylvanian Molas
Formation (San Juan Basin) as a loessite, not as a terra rossa
paleosol, Geological Society of America Abstracts with Programs 31(7):A–160, 1999. Return to text.
- Reed,
J.M. and Evans, J.E., Diagenetic reddening of the Molas Formation (San
Juan Basin): infiltration features in a Pennsylvanian loessite, Geological Society of America Abstracts with Programs 31(7):A–281, 1999. Return to text.
- Silvestru, Ref. 1, p. 103. Return to text.
- Silvestru, E. , Bubbles of surprise, TJ 15(2):89–93, 2001. Return to text.
- Bridges, L.W.D., Tertiary subsurface solution versus Paleozoic karst solution, Guernsey, Wyoming, Geological Society of America Centennial Field Guide—Rocky Mountain Section, p. 205, 1987. Return to text.
- Lovering et al., Ore deposits of the Gilman District, Eagle County, Colorado, United States Geological Survey Professional Paper 1017, p. 32, 1978. Return to text.
- Bridges,
Ref. 8, p. 253. The upper solution breccia, attributed to
paleokarst, contains kaolinite as the chief clay mineral. The
lower solution breccia, not attributed to paleokarst, has illite as the
chief clay mineral. However, kaolinite is a
hydrothermal-alteration product of illite. Therefore, the longer
and more intense the hydrothermal processes are, the more kaolinite
there will be at the expense of illite. Return to text.
- Bridges, Ref. 9, p. 164. Return to text.
- Woodmorappe, J., The rapid formation of granitic rocks: more evidence, TJ 15(2):122–125, 2001. Return to text.
- Snelling, A.A. and Woodmorappe, J., The cooling of thick igneous bodies on a young Earth; in: Walsh, R.E., (Ed.), Proceedings of the Fourth International Conference on Creationism, Technical Volume, Creation Science Fellowship, Pittsburgh, pp. 527–545, 1998. For a popular-level summary of this research, see Woodmorappe, J., Granites ... they didn’t need millions of years of cooling, Creation 21(1):42–44, 1999. Return to text.
- Bridges, Ref. 8, p. 264. Return to text.
Editors’ note
Original manuscript was received on 17 August 2001. It is worth noting
that the papers dealing with alleged paleokarsts by Woodmorappe and Silvestru in this issue of TJ
were prepared independently of each other. Any similarities
between the concepts expressed are due to creationist thinking
converging upon a solution to an alleged problem.
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