An article in the journal of the Australian Skeptics has sought to refute a creationist
claim that the Three Sisters formed during Noah’s Flood. These impressive
rock outcrops are a popular tourist icon near Sydney, Australia. Instead of a refutation,
it turns out that the Skeptic article enhances the creationists’
argument. For example, the article tacitly acknowledges that none of the geological
environments previously proposed is workable, because the author does not attempt
to defend any of them. But the new, previously unpublished model offered turns out
to be an inferior match of the geological evidence. Carbon-14 from wood is still
evidence that the geological strata are young because the explanation that the wood
was an iron concretion is impossible. The article does not even try to refute the
strong evidence provided by the shape of the landscape. The creationist case relies,
not on one or two speculative resemblances, but a whole host of consistent evidences
that tie in beautifully to the sequence of events involved in Noah’s Flood.
The Skeptic article does nothing to diminish the creationist case, but
much to strengthen it.
Creationists have claimed that the geology of Australia’s
Three Sisters, provides compelling evidence for the global Flood of Noah,1
a claim that a recent article in the journal of Australian Skeptics has sought to
refute.2The Skeptic is not a peer-reviewed geological journal,
nor would it profess to be. However, a geologist wrote the article and it is now
available on the web, so a response to the criticisms is given here.
But before we consider the geological evidence, we need to clear away some peripheral
distractions.
Clearing the decks
The author of the Skeptic article seemed outraged that creationists are
trying to mix science and religion. That sense of outrage was expressed in the title,
‘Creationist weds three sisters’ and the opening sentence:
‘Creationist Dr Tasman Walker … has tried to wed the geological unit
that forms the Three Sisters … to his religious beliefs that the geology
of the Earth is the result of Noah’s Flood.’
This is the classic religion-versus-science tactic, regularly employed to sidestep
creationist arguments. Defining science in this way disqualifies the biblical worldview
from the outset, dismissing scientific arguments without addressing them. We are
all sceptical when governments ban opposing political parties. And we should be
sceptical of skeptics claiming that this debate is just about science—about
objectively considering alternative hypotheses and weighing the evidence.
Skeptics are quick to accuse creationists of being biased but won’t acknowledge
that they are biased too. The conflict is between the Christian faith, which gave
the West its values and heritage, and the new religion of secular humanism. Simply
put, one side accepts the Bible as authoritative, the other does not.
The article in the Skeptic reveals its antibiblical prejudice in several
places. For example, in one place the author argues, ‘You do not need to invoke
some magically created worldwide flood to explain sediment dispersal.’ In
another he says, ‘There is no reason to invoke a worldwide flood.’
In other words, there is a stubborn refusal to acknowledge the biblical worldview,
even as a possibility. An open scientific inquiry would willingly contemplate the
question, ‘If there really was a worldwide flood just like the Bible says,
then what evidence would we expect to find?’
A favourite political tactic is to attack the credibility of the opponent. The article
in the Skeptic does just that.
‘Dr Walker is trying to impress his audience with large numbers.’ ‘He
has not bothered to do any research.’ ‘Dr Walker, like all creationists,
never seems to be aware of inconsistencies within his own writings.’ ‘Dr
Walker then continues his assault on science.’
Even the subtitle to the article claims that ‘creationists don’t know
which bed they are in’, implying, among other things, that creationists are
ignorant of geology. However, the article reveals the opposite. It says the Three
Sisters are ‘part of the rock unit known as the Hawkesbury Sandstone’.
Not so. They are exposures of the Banks Wall Sandstone, which is part of the Narrabeen
Group.3 The creationist article always described the Hawkesbury Sandstone
as ‘overlying’ the Three Sisters.1 So, the author of the
Skeptic article has confused his stratigraphy, not the creationist.
A reader of the Skeptic pointed out this error in a letter:
‘This incorrect statement does not appear in Walker’s website article,
where he (Walker) refers correctly (several times) to “… the overlying
Hawkesbury Sandstone …”.’4
The letter goes on to say ‘don’t let our enthusiasm … lead to
misstating the facts of well-known geology.’
The purpose of this enthusiasm is supposedly to ‘demolish the patently
absurd “geology” of the creationists at every opportunity’, which
does not sound like a careful, unbiased scientific approach to the data.
The Skeptic article similarly attacks the credibility of the Bible, referring
to Noah’s Flood as ‘some magically created worldwide flood’ and
‘fairytales’. We should not allow these assaults on credibility to distract
us from properly weighing the evidence.
So let’s look at the geological evidence and how it is interpreted.
Evidence for catastrophe
As the creationist article explained, the immense size and lateral extent of the
geological formations, which the Three Sisters are part of, point to an unusual
depositional environment in the past. Moreover, the ever-present cross-bedding in
the sandstone strata, visible in the cuttings and cliffs around Sydney, means that
deposition was from fast, deep-flowing water.
Any tourist can appreciate these geologic features. But for 150 years, geologists
have struggled to match a satisfactory depositional environment to these strata,
based on normal, everyday geologic environments. The more recent suggestions have
tended toward the exotic and have a distinctive catastrophist flavour. These developments
do not surprise creationists because the geological features are what we would expect
from the global catastrophic Flood of Noah as described in the Bible.
Catastrophe? What catastrophe?
Figure 1. An alluvial fan. A stream or river deposits the alluvium
(gravel, sand, silt, clay and organic matter) onto a valley floor when it emerges
from a steep, narrow canyon (after Stanistreet and McCarthy).21 Note,
vertical exaggeration of sketch is about 300 times.
The article in the Skeptic tries to avoid the implications of large-scale
deposition, first by poking fun. ‘Be impressed by big things.’ ‘Dr
Walker is trying to impress his audience with large numbers.’ Then the author
suggests that large-scale deposition is easy to explain. ‘It seems that he
has not bothered to do any research into modern environments that geologists would
consider similar to that which produced the Hawkesbury Sandstone.’ The article
then suggests that the scale of the Hawkesbury Sandstone is easily explained as
a stream-dominated fan (figure 1).
Now, this is an interesting proposal because this is the first time anyone has suggested
a stream-dominated fan as a modern environment analogous to the Hawkesbury Sandstone.
Over the years, geologists have suggested many different depositional environments,
but these have fallen from favour one after the other:5
Marine (1844)
Partly glacial (1880)
Aeolian (1883)
Aeolian and lacustrine (1883)
Freshwater lake (1920)
Fluvial (1964)
Marine barrier tidal delta (1969)
Braided alluvial (1975, 1980, 1983)
No geologist has previously suggested a stream-dominated fan. I wonder if the author
of the Skeptic article would also say that these geologists have ‘not
bothered to actually do any research into modern environments’.
Figure 2. The Kosi River fan in northern India (after Singh et
al., ref. 10).
This list of ever-changing paleoenvironmental interpretations demonstrates the creationist
point. The Hawkesbury Sandstone challenges the mainstream geological philosophy
that the present is the key to the past. That, of course, is why Dr Patrick Connaghan
of the School of Earth Sciences at Macquarie University proposed deposition by massive
volumes of glacial-lake water. He envisaged that these periodically burst through
ice dams, which accumulated enormous volumes of floodwaters in ancient Lake Napperby
to the north.6
Interestingly, the author of the Skeptic article failed to examine Dr Conagahan’s
model, saying, ‘I have not looked at the newspaper article.’ But that
does not change the fact that creationists are not the only geologists who see that
the evidence points to large-scale watery catastrophe.
By proposing a stream-dominated fan as the past depositional environment, the author
of the Skeptic article effectively acknowledges that none of the previously
proposed environments is satisfactory. I agree. But I doubt that many geologists
will embrace this new depositional model either. Let’s see why.
Figure 3. The Kosi fan is geographically large but nowhere near
as large as the Sydney Basin (after Singh et al., ref. 10, fig. 1, and Jones and
Clark, ref. 3, p. 9).
The Skeptic article refers to the Kosi fan as the world’s largest,
well-studied stream-dominated fan. This fan is in India, on the Kosi River, which
emerges from the Himalayan foothills (figure 2). There are many features of this
example which are inconsistent with the characteristics of the Hawkesbury Sandstone:
Although the Kosi fan covers a large area, it is still not as large as the sediments
within the Sydney Basin (figure 3).7,8 If the largest modern fan is not
large enough,9 how can someone claim that explaining the vast size is
‘no problem’?
The Kosi fan is unconfined but the Sydney Basin is confined between the Lachlan
and New England Fold Belts. This means the Kosi fan is thickest at its source, where
the Kosi River emerges from the Himalayas, and tapers to nothing at its edges.10
Contrast this with the sediments of the Sydney Basin, which have an even thickness
along the length and width of the basin (fig. 4).11
Because the Sydney Basin is confined, it contains a sub-parallel pile of sedimentary
deposits. These are up to 5,000 m thick.12 The maximum thickness
of the Kosi fan is 100 m at its source, i.e. less than 2% of the thickness
of the Sydney Basin, tapering to zero at its extremities (figure 4).10
Figure 4. The thickness and shape of the Kosi fan are starkly different
from the sediments of the Sydney Basin. The cross-section of the Sydney Basin is
parallel to the coast across the mouth of the basin along a SSW-NNE line (obtained
from the Sydney 1:250,000 map, ref. 11, combined with Jones and Clark, ref. 3, p.
9). The cross-section of the Kosi fan is across the widest part of the fan through
Supaul and Purnea (interpreted from Singh et al., ref. 10, fig. 1 and fig. 3, recognizing
that the longitudinal section of their fig. 3 is along the Kosi River toward the
edge of the fan).
The predominant grain-size of sediment reduces along the length of the Kosi fan
from gravel, to sand, to mud,7,10 but the grain-size of the Hawkesbury
Sandstone is relatively consistent over its area.3
The Kosi fan has only one active river channel, which has slowly moved across the
fan in 230 years.7,10 Latest geological interpretations describe the
Hawkesbury Sandstone as a braided alluvial environment (figure 5), which has many
active channels depositing sediment across the area.3
Figure 5. Looking like a complicated braid, a braided stream forms
a tangle of waterways, islands and sandbars as it splits into multitudes of channels
that fork and rejoin. Plentiful sediment load and variable discharge provide the
conditions where braided streams develop. This photograph was taken in 1986 at Leslie
Hills, North Canterbury, NZ.
Oxbow lakes (billabongs) (figure 6) characterize the Kosi fan7 but not
the Hawkesbury Sandstone.3
Outside the active river channel on the Kosi fan, soil formation and intense bioturbation13
would dominate (if the area were not so intensively cultivated).7 Paleosols
(ancient soil horizons) and bioturbated sediments are not characteristic of the
Hawkesbury Sandstone.3
Moisture-loving plants colonize abandoned channels and lakes on the Kosi fan7
but the Hawkesbury Sandstone does not have such vegetated horizons.3
Figure 6. Situated at the bends of meandering streams, oxbow lakes
form when the stream bypasses its channel. Silt rapidly fills in the ends to form
an arc-shaped, stagnant lake.
The Kosi fan may be almost comparable in area with the Hawkesbury Sandstone, but
it is tiny compared with other similar formations, such as those comprising the
Great Artesian Basin, overlying the Sydney Basin to the north (figure 7).14
One such formation, the Precipice Sandstone is 200 m thick, abundantly cross-bedded
and described as a ‘high energy braided stream system’—very similar
to the Hawkesbury Sandstone.15,16
Inconsistencies?
The Skeptic author uses another tactic to try to neutralize the creationist
argument about the large scale of sedimentation. He claims that I have been inconsistent
in the way I have used scale to classify rocks. Specifically, he charges that although
I have argued the Hawkesbury Sandstone is a Flood deposit because of its large scale,
I have previously argued that the much-larger Karumba Basin is post-Flood. Such
a position would be inconsistent, but I have never claimed the Karumba Basin is
post-Flood.
Figure 7. Sediments comprising the Great Artesian Basin, overlying
the Sydney Basin to the north, cover a much larger area. If a stream-dominated fan
is not adequate to explain the Sydney Basin, it is even less applicable to the Great
Artesian Basin, which contains geological formations similar to the Hawkesbury Sandstone.
The author is referring to a letter I wrote to The Australian Geologist,17
which mentioned the famous Riversleigh fossils in Queensland. These fossils are
characteristic of present-day Australian fauna, and so they almost certainly formed
post-Flood, after the land animals migrated to Australia from the Middle East. But
they are contained within limestones of the Karumba Basin, and, judging from its
scale and relationship, the basin is probably late-Flood. To have post-Flood vertebrates
enclosed with a Flood deposit would seem to pose a problem.
However, the apparent problem is easily resolved when we examine the context of
the fossil deposits.18 I explained this in my letter to The Australian
Geologist, ‘The fossils in the limestone are actually contained in
lenses which were once caves and pools formed well after the limestone was deposited.’
Thus, after the limestone was deposited, river channels, caves, pools and
underground conduits dissected it. The animal remains were trapped in these spaces
and fossilized. In other words, the lenses are post-Flood, not the limestone
of the Karumba Basin, which is a Flood deposit.
Carbon-14 in iron concretions?
The article in the Skeptic also tried to discount the import of a carbon-14
analysis on wood from the Hawkesbury Sandstone.19 This returned a date
of 33,720 ± 430 years and provided objective, experimental evidence
that the sandstone is only thousands of years old, not 225–230 million years
as conventionally quoted.
Although the carbon-14 analysis was performed by a reputable commercial laboratory,
the Skeptic article claimed that ‘the sample looked more like an
iron concretion than a piece of wood’. It’s strange that an experienced
carbon-14 dating laboratory would report carbon from an iron concretion.
The Skeptic article also said the carbon-14 result ‘could easily
have been contaminated by ground water’. But the writer ignored the associated
carbon-13 analysis, which is not consistent with ground water contaminating the
wood.
These sorts of arguments about the carbon-14 analysis simply demonstrate what creationists
have said in many places. Geologists accept radioactive ages only when they agree
with what they already believe the age to be.
Broken trees are consistent evidence
The article in the Skeptic tried to dismiss the obvious evidence for catastrophe
provided by the broken tree trunks standing vertically in sandstone outcrops. The
author said ‘floods are well known in modern river systems. There is no reason
to invoke a worldwide flood to explain tree trunks in fluvial deposited sedimentary
rocks.’
However, the vertical logs are at least 3 m long and enclosed within only one or
two beds of a large-scale sandstone formation. These features point to vast and
fast water flows. The Kosi fan does not have similar logs standing vertically in
the earth waiting to be buried by gradually accumulating sediment. Neither do large
logs commonly protrude vertically from the beds of braided-river environments. Thus,
in spite of the author’s attempt to brush off the evidence, it is not possible
to dismiss so easily the significance for catastrophe of the vertical trees within
thick, cross-bedded strata.
Rapid erosion not addressed
The form of the landscapes provides more evidence consistent with the Three Sisters
forming during Noah’s Flood. The creationist article discussed the landscapes
but the Skeptic article did not address them at all. In broad terms, the
landscape in the Blue Mountains consists of an uplifted plateau subsequently dissected
into wide valleys with steep cliffs—a pattern easily explained from a biblical
model.
The plateaux represent a huge planation surface shaved flat during the second half
of the Flood as receding floodwaters flowed in sheets from the continent. The escarpments
and large valleys eroded later in the Flood when the volume of water decreased and
the flow was restricted to large channels. The rivers and waterfalls that now occupy
valleys are minuscule compared with the volume of waters that carved the landscape
during the Flood. Underfit rivers are the norm around the world, but we would expect
conformable-fit rivers if millions of years were available to reach an equilibrium
position.
It is interesting that Darwin, when he visited Australia in 1844, thought the idea
that rivers cut the gorges was ‘preposterous’.20 He proposed
that the main agent of erosion must have been a retreating sea—remarkably
similar to the creationist position.
Conclusion
The article in the Skeptic has not refuted the creationists’ claim
that the Three Sisters provide compelling evidence for Noah’s Flood.
The depositional features of the sediments are different from any depositional environment
we see on the earth today, including the author’s suggestion of a stream-dominated
alluvial fan. The fact that the author proposed a new, previously unpublished model,
rather than trying to defend one of the existing ones, suggests that he thinks none
is adequate to explain the geology.
Thus, the creationist claim still stands, that the geological characteristics of
the Three Sisters are consistent with the global catastrophic Flood of Noah. These
characteristics include:
the geographical extent of the sedimentary deposits
the thickness of the sedimentary deposits
the shape of the sedimentary deposits
the ubiquitous presence of thick, cross-bedded strata in the sediments
the absence of vegetated soil horizons in the strata
the presence of broken tree stumps standing vertically in thickly bedded strata
the presence of carbon-14 in wood enclosed in the sediments
the form of the landscapes such as the extensive plateaus, and wide, deep and steep
valleys.
The case for the Three Sisters forming during Noah’s Flood is strong. It relies,
not on one or two speculative similarities, but a whole host of consistent evidences
that tie in beautifully to the sequence of events involved in the global catastrophe.
The Kosi fan is the largest stream-dominated fan of a class of fans that are deposited
subaerially—i.e. under air on land. Much larger fans are deposited under water
beyond the edge of the continental shelf at the mouths of the earth’s major
rivers, the largest being the Indus deep sea fan. These fans have a different character
and are even less analogous to the Hawkesbury Sandstone.
Singh, H., Parkash, B. and Gohain, K., Facies analysis of the Kosi megafan deposits,
Sedimentary Geology85:87–113, 1993.
Sydney 1:255,000 Geological Map Series, 3rd ed., 1966.
Bioturbation is the churning up of sediment by organisms such as worms or ants.
Usually, bioturbation destroys any layering or structure in the sediment.
The creationist article about the Three Sisters, ref. 1, describes these briefly.
Day, R.W., Whitaker, W.G., Murray, C.G., Wilson, I.H. and Grimes, K.G., Queensland
Geology: A companion volume to the 1:2,500,000 scale geological map, (1975),
Geological Survey of Queensland, Publication 383, Brisbane, p.
127, 1983.
Walker, T., The Great Artesian Basin, Australia, Journal of Creation
10(3):379–390, 1996.
Walker, T., Geology and the Bible—an answer, The Australian Geologist110, p. 8, 31 March 1999.
Archer, M., Hand, S.J. and Godthelp, H., Riversleigh, Reed Books, Sydney
pp. 44–53, 1991.
