Cape Peninsula sandstones, South Africa, deposited during Noah’s Flood

posted in: Landscapes | 1
Maroon mudstone beds and buff sandstone beds alongside Chapman's Peak Drive south of Cape Town.
Maroon mudstone beds and buff sandstone beds alongside Chapman's Peak Drive south of Cape Town.
In the steep road cut alongside Chapman’s Peak Drive, south of Cape Town, South Africa, you can see some of the flat-lying beds of sediment that form the 1000-metre tall mountains along Cape Peninsula. The mudstone has a distinctive maroon colour while the coarser sandstone is buff. The road runs just above the contact between the sandstone and the underlying granite.

Geologists have called these sediments the Graafwater Formation, which is around 70 metres thick along Chapman’s Drive.1 Above it sits another 550 metres of sedimentary strata, the Peninsular Formation, which lacks the distinctive maroon mudstone layers.2 The Peninsula Formation forms the impressive cliff faces prominent in Table Mountain and the escarpments above Chapman’s Peak Road.2

There are many features of these sandstone deposits on the peninsula that point to large-scale, rapid deposition, as you would expect during Noah’s global Flood.

1. The sediments cover a large geographical area. McCarthy and Rubidge have a geologic map that shows the Table Mountain Group extending beyond Port Elizabeth, 700 km to the east, and almost as far as Vanrhynsdorp, 300 km to the north.3 This points to a geologic process that covered a very large area, as would be expected from Noah’s Flood.

2. The sandstone beds are “amazingly uniform”.2 This feature can be seen in the above image of the road cut, but also from a distance when you look at the escarpments in the area, such as the escarpment of Table Mountain or of the Twelve Apostles. Once again, this points to an energetic geologic process that covered a large area.

3. The sandstone beds are frequently quite thick, some as thick as 6 metres.4 This points to a large water flow with abundant sediment, again as would be expected from the Flood catastrophe.

4. The continuous nature of the sedimentation indicates continually rising sea level. There is no evidence of erosion or a break in deposition at the contact between the two formations, so geologists believe that the sediments represent a process of continuous deposition.5

5. Sedimentary structures indicating flowing water are common, including large trough and tabular cross bedding.6

6. Abundant wave and ripple marks, again indicating flowing water.6

7. The sedimentary beds show evidence of slumping, including load casts.6 Imagine how a billiard ball placed on a layer of soft mud would sink into the mud. When sand is deposited onto soft sediment, blobs of sand will sink into the underling mud forming ‘load casts’. These features indicate deposition so rapid that the sediments are still uncompacted and loose.

8. Well rounded quartz pebbles up to 70 mm in diameter are distributed through the sandstone, sometimes forming thin lenses of pebble conglomerate.6 These stones give an idea of the water flow needed to carry them along.

Mainstream geologists don’t connect this evidence for large-scale watery deposition with Noah’s Flood. Often they do not appreciate the catastrophic implications of the evidence they are documenting. That is because they have eliminated any thought from their minds that the Flood actually occurred. The Flood does not form part of their interpretive process and this is a major blind spot in their thinking.

Instead, they try to explain the evidence in terms of geological processes operating at the present time: slow, gradual, limited in scale and energy. Part of their interpretive process is to match the sediments to a modern depositional environment but, as you can imagine, the match is problematical. In the case of these Table Mountain sediments, various opinions have been put forward7 but the sediments do not seem to comfortably match any environments that exist on the earth today.

One suggestion is that the sediments were deposited partly in a river delta and partly in the shallow ocean. The Graafwater Formation supposedly was in a sheltered tidal setting with large areas of still water (presumably to account for the mudstone8). The Peninsula Formation was deposited in a high energy coastal setting with sandy beaches and bars, to explain the abundant, well sorted sand.7

However, there are many features listed above that this environment does not explain, especially their large geographical extent and the evidence for flowing water and rapid sedimentation. More recently, geologists have suggested a major braided river system flowing over a wide continental plain.1 Today, braided rivers carry abundant sediment and form a wide, flat, gravelly river channels. However, there are many features of the sediments that this environment does not explain, including the thickness of the sediment pile.

Noah’s Flood involved flowing water, and that meant landscape erosion and sedimentary deposition. It covered huge areas of the earth as sea level was rising with respect to the continents. It was an ongoing process that took some five months until the entire earth was inundated. It took a further seven months for the waters to recede from the continents into the oceans. The sedimentary rocks forming the Table Mountain Group in South Africa were deposited partway through the first ‘half’ of the Flood as the floodwaters were rising. The evidence is graphic.

References and Notes

1. Compton, J.S., The Rocks and Mountains of Cape Town, Double Storey Books, p.58, 2004.

2. Compton, ref. 1, p. 60.

3. McCarthy, T. and Rubidge, B., The Story of Earth and Life: A Southern African Perspective, Struik Nature, Cape Town, p. 194, 2005. John Compton, ref. 1, has a geologic map on pp. 110–111 that also shows the geographical extent of the Peninsular Formation but his map does not extend as far as Port Elizabeth. Compton’s map on p. 17 shows the geographical extent of the Cape Supergroup which compares well with McCarthy & Rubidge’s.

4. Theron, J.N., Gresse, P.G., Siegfried, H.P. and Rogers, J., The Geology of the Cape Town Area, Department of Mineral and Energy Affairs, Republic of South Africa, p. 27, 1992.

5. Compton, ref. 1, p. 61.

6. Theron, et al., ref. 4, p. 29.

7. Theron, et al., ref. 4, p. 35.

8. It was long thought that mudstone required a long period of time in a still-water environment in order for the fine particles of mud to settle. Recent laboratory experiments have shown that mud can deposit from flowing water.

Further reading

Compton, J.S., The Rocks and Mountains of Cape Town, Double Storey Books, 112 pp., 2004.

Theron, J.N., Gresse, P.G., Siegfried, H.P. and Rogers, J., The Geology of the Cape Town Area, Department of Mineral and Energy Affairs, Republic of South Africa, 140 pp,. 1992.

McCarthy, T. and Rubidge, B., The Story of Earth and Life: A Southern African Perspective, Struik Nature, Cape Town, 334 pp., 2005.

  1. Nils Jansma

    One of the problems with this presentation is that it does not say where the boulders came from. Generally boulders form after a long journey down a fast moving water course traveling over a semi-solid rock bed. The farther they travel, the rounder they become. The rocks at high elevations nearer their source will be more angular than round. It takes time to make a boulder round. The rocks bounce along the bottom of a fast moving stream crashing into one another as well as the bottom of the stream bed. That is why a normal consideration of the facts would include the time for the round boulders to form and then be deposited in the area where the rapidly moving water body begins to slow because of a change in gradient or stream-width.

    There is no doubt that the flood could have moved boulders that already existed, but not necessarily produce them. There wouldn’t be enough time to make them round. If the flood had moved an existing layer of boulders, it would degrade them into a jumbled mess. However, the beds being discussed apparently are dimensionally the same as would be expected if a series of mountain streams converged to form a rapidly moving river which eventually deposited its well rounded heavy stones in the same general area where the river entered a valley or coastal plain. Again, just for review, where did all the round boulders come from, if not from natural processes working over long periods of time in transporting the rocks from their high elevation source to their much lower deposition beds? Just a thought for consideration.

    Tas Walker responds:
    The boulders are deposited in lenses among the sand and silt. The Flood would not have mixed the sediments in a jumbled mess but deposited them in layers as we can see.