Sydney basin section reveals Flood sequence

posted in: Big Picture | 9
Wollongong geological section <br /> west to east. Vertical exaggeration 10.42
Wollongong geological section
west to east. Vertical exaggeration 10.42
Click image to enlarge.
As I have previously mentioned, the Australian geological map series is most helpful for a first assessment of the effects of Noah’s Flood.

The geological section shown here is from the Wollongong 1:250,000 sheet (SI 56 09, second edition, New South Wales Department of Mines, Sydney, 1966). It cuts from the west to the east across the southern corner of the Sydney basin, 150 km south of Sydney. The vertical exaggeration on the section is 10.42 times.

The section shows Permian strata (P—coloured blue). With the vertical exaggeration we can see the strata dip strongly to the east, but they are almost horizontal in the field. They cover a large geographic area, show little deformation and disturbance, and contain many fossils including lots of coal. Further, they sit under the Triassic to Cretaceous sediments that cover a large part of eastern Australia, which contain dinosaur trackways. These features lead me to regard these sediments as Flood deposits, laid down as the floodwaters were rising but before the deposition of the Triassic to Cretaceous sediments of the Great Australian Basin (which was before all air-breathing animals had perished).

These Permian sediments sit on top of rocks classified as Ordivician (O) and Devonian (D) (coloured pink on the section), which are folded and deformed. That fossils are in these sediments indicate they were also laid down during the Flood, but their relative position indicates it was before the Permian sediments. They were folded and deformed as a result of the tectonic movements connected with the Flood catastrophe, and shaved off again and again by the huge water flows across the area during this period.

It’s interesting to look at the land surface on this section. The western portion consists of a plateau about 2000 feet (600 m) above sea level. This drops sharply at an escarpment in the east to a coastal plain.

This is the classic form of landscape expected from the receding waters of Noah’s Flood. First, the floodwater flowed in wide sheets and cut the horizontal plateau. Note how it cuts across the Oridvician and Devonian rocks as well as the Permian ones. Then, as the water flow reduced, it became confined to channels. These cut the wide, deep valleys that dissect the plateau. The volume of water now flowing in those valleys is tiny by comparison with what flowed during the Flood.

Compare the profile of the present land surface with the profiles of ‘previous’ land surfaces as illustrated by the dotted lines delineating the Permian strata (blue). The present landscape is highly irregular with many valleys 1000 feet (300 m) deep or so. Yet the contacts between the different layers in the Permian strata are smooth and even by comparison (between Psb and Psn for example).

This illustrates the differences between the processes operating during the early stage of the Flood (large scale, geographically extensive) and the processes during the final phase of the Flood and post-flood (small scale and geographically restricted). These illustrate some of the characteristics that help us classify sediments within the biblical geological model (see Geological environments and compare the Dispersive rocks with Inundatory rocks).

Once again, the cross sections on these geological maps provide a good overview that allows us to connect the geology within the biblical Flood paradigm. I have found it is much easier to examine these sorts of cross sections rather than to work from the geological column. I think this is because the geological column involves multiple layers of interpretation that tend to mask the processes that are so obvious in the sections. It’s the cross sections allow us to get closer to the raw data in the field.

9 Responses

  1. Philip Rayment

    I’ve wondered before how much they really know about the extent of the layers. Obviously they can see where the layers intersect the surface, including in cuttings, quarries, etc. Then there will be the occasional mine providing deeper information. But how much is conjecture/extrapolation, and how much is really known? This is important when it comes to claims like “the contacts between the different layers in the Permian strata are smooth and even by comparison”.

  2. Tas Walker

    Hi Philip,
    Because the rocks are underground there is always uncertainty about what it really looks like. The geological cross sections are mostly derived by extrapolating underground the geology as mapped on the surface. Other information such as drill holes, gravity surveys, magnetic surveys, etc. are used to improve the reliability of these extrapolations. However, anyone involved in the mining industry will confirm that there are many surprises. Also, ideas about how to extrapolate the geology change with time. As far as the Permian strata in this particular section, we can be more confident than for other areas becasue the strata are exposed in lots of deep valleys across the Sydney basin and there has been lots of coal mining in the area confirming the contacts are generally smooth and even.

  3. April Barbi

    I have a question that has been bothering me for awhile. Could the flood really have happened only 4500 years ago? While debating with someone, to prove that mankind cannot be tens or hundreds of thousands of years old I said, “isn’t it funny that the oldest civilizations go back only about 5000 years?” And he said yes, and the evidence is not destroyed by a flood. That got me thinking, it takes time to build a civilization. If we have evidence of them already existing 5000 years ago, well, they couldn’t have suddenly sprung up from the 8 flood survivors spontaneously. Then I read that the Biblical chronology has Abraham reaching civilized Egypt only 300 years after Noah’s flood. I realize it’s possible that the Bible may skip generations, and “bar” or son can also mean grandson or descendent. With this in mind, taking into account that Egypt was already a great kingdom by the time Abraham and Sarah reached it, there must be more time between Noah and Abraham than 300 years? Any thoughts?

  4. Tas Walker

    Hi April,
    We need to consider how the different dates are worked out. In the case of the Flood it is straightforward, working from the chronologies and associated evidence within the Bible. In the case of the other civilizations the process requires different sorts of assumptions. This article about Egyptian chronology illustrates the sorts of issues involved. There are many articles on about chronology, and those about Jericho, David and Solomon would be of interest. Use their search box.

    About the period of 300 years for the Egyptian civilization, just look at how Australia and the US have developed in such a short time. It is related to the attitude, skills and abilities of the people. I don’t think there are gaps in the genealogies. And even if they were, it would not extend the time span by one year. (See Biblical chronogenealogies.)

  5. April Barbi

    Thank you, Tas. This is a very interesting subject to me right now. I’m reading the material you suggested and other things, too. It’s wonderful to be able to ask what seem like difficult questions and to find that the Word of God is always trustworthy.

  6. Kimbal


    I wondered if you have much material on the “dinosaur trackways” mentioned above? I know in many cases the tracks found around the Grand Canyon seem to all go in one direction and finally they puzzled scientists until they realized the changing tracks were a result of animals half-running half-swimming in waters that were nearly over their heads! Great stuff! So do the trackways you mentioned have similarities?

    Thanks for all you do!

    Kimbal aka Radar

  7. Kimbal


    I do recall that Manetho, one of the chroniclers of Egyptian history, mentions the Tower of Babel and that the Egyptians were descended from Cush, so the idea of an Egyptian culture that predates Babel does not compute. Many of us believe that later Egyptian historians added years to the histories to aggrandize the Egyptian Empire. In fact this has happened in other cultures as well. To some extent the record of the ancestors that is in Genesis often gets “Chinese Telephoned” in the tales of lineage in other cultures. Bill Cooper’s “After The Flood” has a tremendous amount of research into genealogies of the Europeans in particular that you might find interesting.