Why Clastic Dykes don't Indicate a Global Flood

Copyright 2002 G.R. Morton. This can be freely distributed so long as no changes are made and no charges are made. (home.entouch.net/dmd/clasdyke.htm)

Ariel Roth has an article in Origins 19(1992):1:44-48 entitled “Clastic Pipes in Dikes in Kodachrome Basin.” The article can be found on the web at http://www.grisda.org/origins/19044.htm. In this article, Roth claims that clastic dykes are evidence for a young-age earth and evidence for catastrophism associated with the flood. We will examine his claims here but a few definitions are in order for those who don't know what a clastic dyke is. (UK spelling, dyke; American spelling, dike--I first worked them in Scotland so I will follow that spelling).

A clastic dyke is an intrusion of sediment into an overlying sedimentary rock. Normally clastic dykes are of sands injected into overlying shale and that is what I will speak of. The reason most clastic dykes are sands injected into shales is due to the fact that the shales above the sand prevent water from escaping the sand as the sand compacts. The situation is like this:

1. sand mud deposition       2.      Compaction &         3. Earthquake
                                     added weight

------------------------     ------------------------     ---------/-----|  |--------------
impermeable mud                      shale                    \  /      \|  |/   /  \| |/injections
------------------------     ------------------------    -----------------^---------- ^ ---
water-filled sand                    H2O can't escape           pressure reduced
                                     overpressured            water escapes up injections
------------------------     ------------------------    ----------------------------------

In step 1 you have had a sand deposited and then it was covered by a mud. When a sand is first deposited it has a porosity between 25-50% (Freeze and Cherry, 1979, p. 37). If the sand has a porosity of 50%, this means that it will be 50% sand and 50% water by volume. As it is buried, and weight compresses it, the water is squeezed out and the sand grains settle closer to each other. If the mud compacts quickly, it prevents water from escaping from the sand below.

Water escape is essential for a sedimentary layer to compact as more and more sediment is piled on top of it. If the mud (now compacted to a shale) above the sand, is impermeable, the water gets trapped and can't escape. Because the sediments are continuously being buried, the pressure in the water rises (step 2). This is a stage where essentially the overburden of rock is being supported by the water itself, not by the rock grains and this is unstable. When eventually step 3 comes along, an earthquake, the slight fractures in the shale caused by the earthquake, allow the water to explosively move up the fractures, but they carry some of the sand with them. This is what causes the clastic dyke. And when the water finds a way to escape from its overpressured prison, the clastic injection ceases and the water flows through the injected sand from the sand below to the surface above. This is the accepted mechanism for clastic dyke formation.

Now, Ariel Roth says some rather strange things about the formation of clastic dykes. First he says that the long times between the deposition of the sand layer and the deposition of the overlying mud layer and its transformation into shale proves that something odd is afoot in the formation of clastic dykes. He writes:

“Sediments cannot remain soft forever; they tend to become cemented. Cementation occurs when dissolved minerals are carried by water into the sediments, hardening them into rocks. Some other features of these pipes also suggest that there was not much time between deposition of these layers and recent (Plio-Pleistocene) geologic activity. The conundrum is that the standard geologic time scale implies well over 150 million years between laying down of these sediments and what appears to be the time of intrusion.” (Roth, 1992)

The above statement assumes wrongly, that mere age causes rocks to become hard. Sediments are not dried bananas! When sand is first deposited, it has porosities of between 25 to 50%, silts and clays (muds) have between 35 and 70% porosity (This is very old knowledge, see Freeze and Cherry, 1979 and compare with similar values in Hedberg, 1926.). There are two processes which turn sediment into hard rock. The first is compaction, which takes place as the sediment is buried deeper and deeper by overlying sediments. This phenomenon presses the water out of the rock and forces the lithologic particles closer and closer. But that alone doesn't turn a sediment into hard rock. Cementation is the process whereby some form of mineral deposition occurs in the pore spaces between the rock grains, cementing them up. Muds simply won't become solid rock(shale) until they have been compressed by overlying sediments and cementation takes place. Those processes take at least 1000 feet of overburden. Lithification is caused by several factors, none of which are age. Hedberg writes:

“Although immediately after deposition muds may have porosities of 70 to 90 per cent, silts from 50 to 70 per cent, and sands from 30 to 50 per cent, the porosities of shales and sandstones are rarely above 30 per cent, and are usually much lower. This reduction in porosity is accomplished largely by (1) closer packing of particles with elimination of interstitial water, (2) granulation and deformation of particles, (3) recrystallization, and (4) cementation and secondary growth.” (Hedberg 1926, p. 1042)

Roth writes:

    “These pipes appear to present a problem for the standard geologic time scale, since it would require that the Jurassic formations which serve as source for the intrusions remain soft (uncemented by minerals) for over 150 million years. Considering how easily cementing minerals are transported through sediments by water, this seems highly unlikely. It also seems highly unlikely that a delithification process (dissolving of cement) would take place at the same time throughout the thick and highly varied sequence over the widespread area in which these pipes are found.” (Roth, 1992)

Note in the above, that even depth isn't listed as a factor in lithification. Sediments can remain unconsolidated for millions of years as long as they are not buried deeply and in places where they lack carbonate cement. I drilled a well in Lee County, Texas and encountered an unconsolidated sand at 3,300 feet deep. Depth alone will not cause a rock to become hard either. That particular sand was full of oil and made for a great well. The age of that rock was Eocene--about 50 million years old. A recent well drilled in the North Sea to a depth of around 6,000 feet found unconsolidated sands. The core, (a cylinder of rock) we cut from the well bore had a sand which, if you pressed with your finger, was like beach sand. It was only partially cemented. It too is 50 million years old and buried deeply.

Roth's statement, (An overburden of more than 1200m (4000') of sediment once covered the now-exposed area where these pipes are found. This overburden would create a pressure of 275×105 Pascals (4000 lb/in2). Such pressure would induce rapid cementation, precluding a Plio-Pleistocene intrusion.) is falsified by the oil well observations above. If 4000 feet of over burden causes ‘rapid cementation,’ why don't we see it in wells we drill today? Roth needs to go actually drill some oil wells and see what is beneath his feet. Roth is raising non-issues and red-herrings in his search for evidence of a young earth.

Acknowledgement: Thanks to Kevin Henke for many excellent criticisms of the original page.


  • Freeze, R.A. and J.A. Cherry, 1979, “Groundwater,” Prentice-Hall, Inc. Englewood Cliffs, NJ.
  • Hedberg, Hollis D., “The Effect of Gravitational Compaction on the Structure of Sedimentary Rocks” AAPG Bulletin, 10(1926):11:1035-1072
  • Roth, Ariel, “Clastic Pipes in Dikes in Kodachrome Basin,” Origins 19(1992):1:44-48 http://www.grisda.org/origins/19044.htm

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