Rock language: is there such a thing?
by Dr Tas Walker
ref. 2.
Have you heard the saying ‘The rocks speak out’? But can you
understand what they say?
Let’s see.
Look for a moment at the sedimentary deposit shown in the photograph (figure 1).
It is 1.5m thick.
You can see the bottom portion of the deposit, marked D, is dark, massive and without
any clear structure. The next section, marked C, has a few horizontal layers, some
that are light coloured and others dark. Above that, the section marked B is made
of mostly light sand, which looks like there are a few waves or dunes in it. The
whole sequence is capped by a dark layer at the top, marked A.
Geologists interpret past environments from such exposures of rock. The idea is
that the rocks tell us what happened in the past. But it is people who do the talking;
the rocks are silent. That is, the interpretation is determined by perspective.
Let’s try to interpret these sedimentary layers shown in the section. This
is what we could say:
‘The bottom sediments were deposited in shallow mudflats along an ancient
coastline. Worms and other organisms, as they grazed for food in the mud, disturbed
the sediment and left it without any clear structure.
‘As more sediment accumulated in the area, the shoreline gradually advanced
seaward, and the mudflats were covered with beach sand. The flat strata were deposited
in the zone on the beach that was affected by the tides. The dark and light strata
represent periods of time when the ocean levels sometimes increased and other times
decreased: a time of rapid small scale sea transgressions and regressions.
‘More sediment accumulated and the coast line continued to build seaward.
Eventually the area was covered by small sandy dunes at the top of the beach. Gentle
winds helped move the sand up the beach. Just beyond the sand dunes, in a perched
lake environment, leaves and twigs from the vegetation in the area accumulated in
a shallow marsh.’
You can see all this clearly in an illustration of the environment in figure 2.
Geologists routinely interpret past geological environments from the rock layers
in this way. It’s part of their job. Here is an example of what they say about
the so-called Carboniferous period, which they put at 300 million years ago:
‘Along the margins of the seas, quantities of detritus [accumulated fragments]
from eroding mountain chains were carried down by rivers to form wide deltas and
delta swamps.’1
We often read such interpretations in the media, in tourist brochures, and in school
books. The descriptions can be vivid and almost give the impression that the geologists
were there to see what was going on.
So, how do we rate our interpretation of the sand deposit in figure 1?
Not too well. Even though the interpretation was plausible and convincing, it is
wrong.
In this case, we know how the sediments in figure 1 were deposited. People saw it
happen. This sand was deposited in a New Orleans neighbourhood on 29 August 2005
as a result of Hurricane Katrina.2
After Nelson and Leclair, ref. 2.
The hurricane produced a storm surge which burst the levee on the London Avenue
Canal, flooding the area and depositing sediment as shown in figure3. The section
we interpreted was photographed in front of house number 2 (labelled on figure) as
workmen cleared the debris away.
The levee burst between 7 and 8 am, and the torrent of water was so powerful that
it lifted one house from its foundation, moved it 35m (115 ft) into a tree, and
turned it around (red house in figure 3). Repairs to the breach began after two
days.
The whole 1.5m (5 ft) of sand was deposited quickly as water flooded into the neighbourhood.
Rather than representing different environments over long periods of time, the sediments
represent rapidly changing flow conditions.
The bottom section represents the first sediments carried into the area by the initial
turbulent torrent. The flat layers above were deposited from a continuous flow of
high-velocity water as the water level in the neighbourhood rose. The next section,
with the sand dunes, was deposited when the water slowed down. And the organic twigs
and leaves were left in a layer on the top.
The whole deposit was laid down quickly during one catastrophe in about a day.
Clare Bond from the University of Glasgow, and other researchers from the UK investigated
human bias in geological interpretation. Consulting with over 200 professional geoscientists
they found that a person’s previous experience affects how they interpret
geological evidence.3 Industry needs to know what risks they face when making major
decisions based on the interpretations of geological data.
Clearly, the way we interpret rocks depends on what we think happened in the past.
Those who start with wrong ideas about the past will be wrong in their interpretation
of the data—even if they have a detailed, plausible and consistent story.
The big risk is in not recognizing catastrophic deposits.
That is the situation with modern geology. Most geologists have decided from the
outset that the huge catastrophe of Noah’s Flood did not happen.4 So they
interpret the rocks in terms of stable environments over millions of years.
These explanations are often logical, detailed and plausible (although there are
always things that don’t add up, but these are generally overlooked). However,
we know that these explanations are wrong because of the eyewitness report in the
Bible about the global Flood. And when we do take the Flood into account, we find
that it makes good sense of the evidence.5
We must change the way we interpret the rocks, starting from the true history of
the world as recorded in the Bible. Not only do we need better geological understanding,
but more importantly we will see that the Bible is reliable and heed its life changing
message.
References and notes
- Hallam, A., Planet Earth: An Encyclopaedia of Geology,
Elsevier International, Oxford, UK, p. 206, 1977. Return to text.
- Nelson, S.A. and Leclair, S.F., Katrina’s unique splay
deposits in a New Orleans neighborhood, GSA Today 16(9):4–10,
September 2006. Return to text.
- Bond, C.E. et al., Human bias in geological
interpretation—how much uncertainty does it introduce? AAPG International
Conference and Exhibition, Technical Program, 5–8 November 2006,
<aapg.confex.com/aapg/2006int/techprogram/A107418.htm>. Return
to text.
- James Hutton (1726–97) was the first to assert, ‘The
past history of our globe must be explained by what can be seen to be happening
now’—the philosophy of uniformitarianism which excludes Noah’s
Flood from the outset (quoted in Holmes, A. Principles of Physical Geology.,
Nelson, London, p. 43, 1965). Return to text.
- See for example Geology Questions and Answers, <creation.com/geology>.
Return to text.
Creation.com reaches millions of people each year–many of these aren’t believers in our Creator and Savior Jesus Christ. How will we reach them without your support? Please consider a small gift today. 
|
