Young Earth Creationist Weds Three Sisters

Paul Blake
(Revised and updated 2 April 2004)

Paul completed his Bachelor of Science in 1989 at the University of Queensland majoring in geology, and his Honours in 1990 majoring in geology and palaeontology.  Since 1991 he has worked for the Geological Survey of Queensland which is part of the Department of Natural Resources and Mines, and is currently doing a PhD part-time on "The Middle Palaeozoic corals and tectonic evolution of central coastal Queensland".

He is a member of the Geological Society of Australia
, Association of Australasian Palaeontologists, Petroleum Exploration Society of Australia, and the Australasian Evolution Society.  Paul's website can be found here.

Young Earth creationist (YEC) Dr Tasman Walker of Answers in Genesis has tried to wed the geological unit that forms the Three Sisters in the Blue Mountains of New South Wales to his religious beliefs that the geology of the Earth is the result of Noah's Flood1.  The article by Dr Walker can be found at Three Sisters: evidence for Noah's Flood.


The Three Sisters are made of sandstone that is part of the Sydney basin.  Although Dr Walker claims that the Three Sisters are "compelling evidence for the global Flood described in the Bible" most of the discussion on the evidence for catastrophic deposition in the article is about the Hawkesbury Sandstone.  The Three Sisters are formed by the geological unit known as the Banks Wall Sandstone2, not the Hawkesbury Sandstone, and does not contain any of the geological features that has led Dr Conaghan to propose large-scale (but not global) floods.

Be impressed by big things.


After the introduction where Dr Walker discusses the National Park and the scenery around the Three Sisters his first statements are regarding the size of the Sydney Basin and some of its equivalents.  He says (with figure references removed):


But the strata extend much further than we can see from the lookout.  From Katoomba they reach 160 km (100 miles) south, 160 km north, and 160 km to the east—an immense rectangular deposit of sediment.  Geologists call it the Sydney Basin, the resting place for massive volumes of sediment eroded from the Lachlan Fold Belt to the west, and the New England Fold Belt to the east.


Many geologists consider the Sydney Basin is the southern end of a 250-km (160-mile) wide system extending 2,000 km (1,200 miles) north. The immense size of the deposit is evidence for catastrophe…


Dr Walker is trying to impress his audience with large numbers.  It seems that he has not bothered to actually do any research into modern environments that geologists would consider similar to that which produced the Hawkesbury Sandstone.  If he had he would have discovered that stream dominated fans can deposit sediment over areas that can be hundreds of kilometres in radius.  The largest, well-studied stream dominated fan is that of the Kosi River which emerges from the Himalayan foothills to build a fan into the Ganges River valley.  This fan is about 125 km wide and 125 km long3.  Clearly, you do not need to invoke some magically created worldwide flood to explain sediment dispersal over large areas.


Since multiple rivers can enter a single sedimentary basin and each can produce a fan, there is also no problem explaining the 2000 km extent mentioned by Dr Walker.


Also Dr Walker, like all creationists, never seems to be aware of inconsistencies within his own writings.  Above he believes that an area 250 x 2000 km is too large to be explained by modern sedimentological environments, but in the past has indicated that he believes that the sediments of the Karumba Basin, which covers an area of about 1200 x 1000 km, is post-Flood4 and therefore must have been formed by modern sedimentological processes.


Going with the Flow


Dr Walker then continues his assault on science by trying to use crossbedding to convince the gullible that only Noah's Flood could have the energy necessary to move the sediment that makes up the Hawkesbury Sandstone.


Crossbedding is formed when dunes (sandwaves) migrate over an area.  Sedimentary material is carried along the bottom of the river and when it reached the crest of the dune the material is deposited on the front slope of the dune to form a thin layer that is at a distinct angle to the horizontal (figure 1).  The cross bedding dips in the direction of the flow of the current.



Figure 1: This photo is of a steeply dipping bed of sandstone.  The photo has been rotated to bring it back to almost horizontal.  When this sandstone was originally deposited the bedding would have been horizontal.  The cross bedding can be clearly seen at an angle to the bedding planes.  Given the dips on the cross bedding, the water that deposited this rock would have flowed from the left side of the picture to the right.


In his article Dr Walker writes (with figure references modified):


From the size of the cross beds, geologist Dr Patrick Conaghan, Senior Lecturer at the School of Earth Sciences at Macquarie University, determined the conditions under which the sand was deposited.  In 1994 he described a wall of water up to 20 m (65 feet) high and 250 km (150 miles) wide coming down from the north at enormous speed*.  This catastrophic interpretation is consistent with what we would expect during the Biblical Flood.


* Woodford, J., Rock doctor catches up with our prehistoric surf, The Sydney Morning Herald 30 April, 1994, p. 2.  For more detail, see: Conaghan, P.J., The Hawkesbury Sandstone: gross characteristics and depositional environment, Bulletin, Geological Survey of New South Wales 26:188–253, 1980.


Of the two references that Dr Walker gives for the above quote I chose to first investigate the article from the Bulletin of the Geological Survey of New South Wales since this was the only peer reviewed source of scientific information for the claim.  However, instead of finding "more detail" about this amazing "wall of water" I found none.


Dr Conaghan interprets the Hawkesbury Sandstone to have been deposited in a fluvial (river) environment.  In the report we find passages such as these:


Directions of foreset inclination for more than 5,000 crossbed sets throughout the entire area show a unimodal pattern…  Moreover, the conspicuous channel-like structures of the massive sandstone lithosome are generally aligned in this same direction…  These characteristics, together with the high ratio of sandstone to mudstone, are those considered diagnostic of the sediments of low-sinuosity fluvial environments.


Dimensions of the larger sets [of cross beds] require generative sandwaves from 1 m to more than 5 m high, and in some instances, more than 100 m wide.  Sandwaves of these dimensions are recorded from rivers, though the larger are known only from soundings. [original author's emphasis]


Dr Conaghan does suggest flooding for some of the bed forms of the Hawkesbury Sandstone, but shows that the same kinds of sedimentary deposits have been found in the flood deposits of modern rivers -


That the sheet sandstone lithosome is dominated by the relicts of straight crested and lunate sandwaves can be attributed to preferential preservation of flood or high stage bedforms, such as the Brahmaputra River examples.


Surely Dr Walker read this since he references Dr Conaghan's paper.


Given that the Hawkesbury Sandstone can be explained by referring to modern environment there is no reason to invoke Noah's Flood.


What about the "wall of water up to 20 m (65 feet) high and 250 km (150 miles) wide"?  I did not find it mentioned in the article in the Bulletin of the Geological Survey of New South Wales.  It seems that the only place this fact can be found is in the news article referenced above.  If creationists have to resort to getting their scientific facts from newspaper articles then their cause is truly pathetic.


However, the pathetic nature of creationist "research" becomes even more apparent after reading the newspaper article.  It is obvious that Dr Walker has never bothered to actually read the newspaper article that he quotes.  If he had he would have seen that the article says-


The initial force of the floods left kilometre-long layers of almost structureless sediment which were up to tens of metres thick.


So it was the structureless sandstones within the Hawkesbury Sandstone that piqued Dr Conaghan's scientific curiosity and not the cross beds as claimed by Dr Walker.  The newspaper article clearly states that each individual flood that produced these massive sandstones (and there were thousands of these floods) were caused by glacial lakes bursting through ice dams.  These sorts of floods are known as jökulhlaups and occur in modern day Iceland.  So once again there is a modern day environment capable of producing the features seen in the Hawkesbury Sandstone.


What about carbon dating?


Dr Walker refers to a paper by Dr Snelling where a supposed piece of wood from the Hawkesbury Sandstone was submitted for carbon dating5.  The 225 to 230 million year old piece of "wood" returned a date of 33,720+/-430 years.  However, as outlined at Index to Creationist Claims the sample was porous and could easily have been contaminated by ground water.  Also, the lab that performed the test recorded that the sample looked more like an iron concretion than a piece of wood.


Polystrate fossils


Dr Walker's article finishes with a picture of broken tree trunks standing vertically in a sandstone outcrop and writes:


The trunks are broken with no sign of soil or roots.  They testify to the violent forces which uprooted and smashed an ancient forest...


However, 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.




Once again the creationists have failed to make a convincing argument for why current mainstream science should be rejected in favour of their fairytales.  When the geological evidence is honestly examined it is found that it best fits the Actualism model used by modern geologists.




Thanks to Dr Patrick Conaghan for providing me with valuable information that was used in writing this article.




[1] WALKER, T., 2003: Three Sisters: Evidence for Noah’s Flood, Creation 25(2), p. 38–42.


[2] BEMBRICK, C.S., 1980: Geology of the Blue Mountains, western Sydney Basin, Bulletin, Geological Survey of New South Wales 26, p. 134–162. (particularly note photo 8.1 on p. 144).


[3] COLLINSON, J.D., 1986: Alluvial Sediments.  In READING, H.G. (Ed.) Sedimentary Environments and Facies.  Blackwell Scientific Publications.


[4] In the "Letters to the Editor" section of The Australian Geologist Newsletter ISSN 0312-4711, issue No. 110.


[5] Snelling, A.A., Dating dilemma: fossil wood in "ancient" sandstone, Creation 21(3), p.39–41, 1999.