Classification Criteria for Geology in the Field

© Tas Walker  May 05

How can we determine where geologic units fit in the scheme?

From the Biblical model we infer that geologic processes acting in the past varied in nature and intensity, and were different from what we experience today. Consequently it is anticipated that certain geologic characteristics will help classify rocks in accordance with the model. A preliminary list of useful characteristics for classifying a geological structure include:

• Physical scale
• Degree of disturbance
• Response to disturbance
• Texture
• Fossils
• Coal
• Raindrops
• Natives
• Footprints
• Post Depositional Erosion
• Flat Topped Landforms

You will be able to add to this list as additional criteria are found useful by experience. Classification criteria should be used jointly to determine where a rock structure belongs in the biblical framework and not used in isolation.

The Place of the Supernatural in the Creation Event

The aim of scientific research is to understand the relationship between cause and effect, or in the case of geology, process and product. For the Creation event we do not know the nature of the creative processes or the form of the created outcomes. The events of the first six days certainly cannot be explained using natural laws in isolation because creation involved supernatural acts. However we can draw limited conclusions assuming natural laws would have operated once supernatural actions were complete. For example, the first bird was created supernaturally by processes not humanly observed and never repeated. Immediately the creature was formed its physiological functions such as breathing, blood circulation, and digestion, would have functioned as we observe today. Using similar logic we can anticipate that after the Earth was created supernaturally on the first day the subsequent processes such as the movement of water and the precipitation of dissolved material would have followed natural laws.

Limited conclusions can also be drawn about the form of the initial creation. We would not expect God to create rocks instantaneously with the appearance of a prior history. For example, a fossil in a rock appears to be the remains of a creature which has lived and died before the rock was formed. Most creationists today are of the opinion that fossils were not created instantaneously within the rocks. Apart from the illusion of history, the appearance of dead fossils would not be consistent with a good creation. Fossils are easily explained as creatures destroyed during the Flood event.

Just as fossils indicate a prior history, most sedimentary and metamorphic rocks appear to be derived from pre-existing source rocks. Consequently we would not regard these as having been instantaneously created by God. This is not to say that sedimentary or metamorphic rocks were not produced during the Creation event by natural processes operating at that time. However rocks created instantaneously by God out of nothing would not be derived from pre-existing source rocks.

Physical Scale

The intensity of geologic processes was different at different times in the past producing geologic structures of different geographical extent. A structure's scale will therefore indicate the strength of the process involved in its formation. A geologic structure can have a world-wide, continental, regional, or local scale. Scale also includes the thickness of the structures. Scale is therefore expected to help classify geologic structures according to the Biblical model.

As a convenient measure four categories of scale are defined: world scale, continental scale, regional scale and local scale. Perhaps the most useful single parameter is the volume of material in a geological structure. A helpful scheme is set out in the following figure. This figure indicates, for example, that a world scale structure would involve more than 100,000,000 km³ of material whereas continental scale structures would involve between 100,000,000 km³ and 10,000 km³ of material. Typical dimensions to achieve a volume of 100,000,000 km³ would be 3000 km by 3000 km in aerial extent coupled with a thickness of 10 km. Any combination of dimensions achieving a comparable volume could be considered equivalent from a scale point of view.

The physical scale of rock structures will help will help classify rock structures within the biblical model.

Degree of Disturbance

The degree of disturbance of a geological structure depends on the number and intensity of tectonic actions to which the structure was exposed. This in turn would depend on the time the structure was formed. The biblical model sets out the following sequence for past geologic events:

• The Foundational Action
• The Formative Action
• The Eruptive Action
• The Abative Action

Response to Disturbance

The Biblical model sets out the following time relationship for past geologic actions:

The above time-line illustrates the history of the earth as set out in the Bible. Various key events are indicated. The dates shown are from Ussher's chronology which was based on internal evidence from the Bible itself. By adding the years given in the genealogies and relating these to chronological information in other passages he determined the dates for the accompanying events. I use Ussher because his chronology is well known. The dates shown on the timeline are:

The response of geologic structures to disturbances depends on how soon they were disturbed after they were formed. Rocks may respond in a:

• plastic manner - oozing, twisting, bending and folding.
• brittle manner - faulting, crushing, and fracturing.

The response of rocks to imposed stress is complicated. Even hard and brittle rocks can respond in a plastic manner if they are deeply buried when disturbed. It should also be noted that the concept of brittle and plastic depends on the scale at which the units are viewed. For example, numerous, small, brittle failures can add together to give smooth curves when viewed from a distance, like a plastic response.

The biblical geological model introduces two additional factors affecting the response of rocks to disturbances, factors not normally considered in uniformitarian models. The first factor involves the extent to which a sediment has hardened since deposition and before disturbance. Material properties of rocks such as fracture strength, elasticity and viscosity which prescribe how the rock will respond to disturbance all depend on the degree of diagenesis. This in turn depends on such factors as the physical and chemical characteristics of the rock material, temperature and pressure resulting from depth of burial, and the time between deposition and disturbance. Given the right chemical situation, soft sediment can cement rapidly. Concrete, for example, can set within a few hours and reach full strength after a month or two. Yet, even though sediments could harden quickly, the biblical model suggests that sometimes rocks would have deformed while still soft.

The second factor arises because large volumes of sediments would be deposited rapidly and contain significant water. The presence of water reduces the stress required to deform the sediments and assists the relative movement of grains to each other.

It is expected that response of rocks to disturbance will help classify units within the biblical model when the timing of geological actions is taken into account.

Texture

From the biblical model we envision that the hardness of source material would vary from time to time as would the erosive intensity of water-driven geologic processes. These differences would affect the texture of the resultant sedimentary rocks. For example, rocks formed from fine, soft, unconsolidated source material would have a fine texture, no matter how intense the erosive action of flowing water. On the other hand, the texture of rocks derived from hardened source material would depend on the erosive intensity of the water flows. Intense erosive action on hard, strong source rock would produce rocks of coarse texture such as conglomerates and breccias. Clasts of soft sediments could be eroded from partially hardened source rock. These would exhibit plastic behaviour after deposition or be rounded in shape.

Also related to texture is the metaphysical question of the form of rocks emplaced during the Original phase of the Creation event. The concept of the Original phase is of an instantaneous supernatural creation out of nothing at the beginning of the first day. It is proposed that such created rocks would not appear to be derived from pre-existing source rocks. Consequently sedimentary and metamorphic rocks would not have formed during the Original phase of the Creation event.

Another metaphysical question is whether volcanic activity occurred during the Creation event producing extrusive igneous rocks. Considering that each step in the creation process during the Creation event was described as "good" by the Creator (e.g. Genesis 1:4), it is hard to conceive of highly explosive volcanic activity at this time. For the sky to be filled with debris ejected by volcanic eruptions and accumulating into large pyroclastic deposits runs counter to the concept of a perfect creation. It certainly would not be "good" for the atmosphere to be dense with scalding hot ash that settled and welded itself into crystal tuff. Nor is it likely that the contamination would clear in time, ready for the creation of birds, animals and people within a few days because ash can persist in the atmosphere for weeks or months after volcanic eruptions. It is unlikely therefore that tuffs and pyroclastics would have formed during the Creation event.

Some igneous rocks may have formed during the Creation event without spoiling the new creation if magmatic material extruded under the ocean or injected within the crust of the earth without harm. Extrusive volcanic rocks could form on land provided the extrusion was not explosive or injurious to the environment and provided the lava flow was in an isolated location where it could cause no damage. These processes however would not produce pyroclastics or crystal tuffs.

Rock texture is expected to be useful for classifying rocks.

Fossils

Fossils are the remains of organisms that lived in the past. Metaphysically, it is considered that all fossils formed since life was created during the Creation event and that no fossils were created supernaturally within the rocks.

Fossils indicate rapid burial of living creatures before they decompose, and before being consumed by other creatures. The state of preservation of the fossil indicates how quickly the organism was buried, and whether it was subsequently disturbed. The distribution of fossils would reflect the distribution of life on the earth at the time of the Flood and the order in which they were buried by the Flood. Fossils could not occur before life was created. The requirement for rapid burial makes it more likely for fossils to form during the Flood than during the Lost-World or New-World eras.

Note that the Biotic phase has been included within the Creation event to allow for the remote possibility that some plankton or other organic material may have become trapped after its creation when sediments were forming in the oceans. This raises the metaphysical issue of "death before the curse of death which followed Adam's sin". However, the Bible never ascribes to plants the attributes of a "living thing" and therefore they could not die when consumed.¹ Consequently the possibility of fossiliferous organic material within rocks formed during the Creation event is not inconsistent with the biblical record.

The use of fossils to correlate strata is fundamental to current geological practice and routinely employed to interpret geological structures within a region. Fossils have been used to set up geological systems with their alleged world wide "time zones". As such they are utilized to tie regional geology from different parts of the world into a universal time sequence. From a biblical perspective, fossils should be useful for classifying rocks on a regional basis and their distribution would relate to the progressive destruction of biogeographical zones. However, the biblical model provides no basis for assuming a time correlation between regions based on fossil evidence. This would require each index fossil to be deposited worldwide at the same time during the whole of the Flood event.

Fossils can be used to guide classification within the biblical model.

Reference

1. Stambaugh, J., 1992. 'Life' according to the Bible, and the scientific evidence, CEN Technical Journal, 6(2):98-121.

Coal

It is considered that vegetation buried during the Flood produced coal. Mechanisms would be different from the slow and gradual processes for peat accumulation observed today. Possible mechanisms include:

• Large scale cyclic dumping of floating vegetation on shore lines by tectonically controlled hydraulic deposition
• Lake deposits as observed after the explosion of Mt St Helens
• Deposits in vegetation traps created by ground topology
• Burial initiated by accumulation of pyroclastic volcanic ash

Coal rank and quality could indicate when burial took place, whether it was in fresh water or in salty water, how long the vegetation was floating before it was buried, and the presence of suitable catalysts. Coal can be used as a guide for classifying rocks.

Raindrops

Raindrops are commonly found in rock formations and may help classify rocks. Raindrops are significant because the surface must be exposed to rain. This would rule out the Foundational Rocks of the Creation Event. Also there would be some period of time during the Flood toward the end of the Inundatory Stage and the beginning of the Recessive stage when raindrops could not form because the surface was covered by water.

Natives

Many countries, like Australia, have distinctive animal populations. We would not expect kangaroos, for example, to travel to Noah's Ark from Australia before the Flood, and then return to Australia from the Middle East after the Flood. (Australia, as such did not exist before the Flood.) Consequently, the kinds of animals represented in the fossil record of a country may help distinguish between Flood and New-World Rocks. Such an analysis must ensure that the fossils have been properly identified, allow for variation within created kinds, and consider environmental changes during the New-World Era.

We would not expect the fossils found in Flood rocks to correlate strongly with the native animals in that country. Flood Rocks should contain fossils of some animals from other countries and lack some native fossils. On the other hand we would expect a good correlation between the kinds of fossils found in New-World Rocks and the native animals of that country.

Footprints

Footprints of animals, birds and humans have been found in rock formations and their presence is important. Footprints could not be made in Creation rocks because animals did not exist during the time Creation rocks were formed. Furthermore, footprints would not be made in the Recessive stage of the Flood event because all land animals were dead at this time. The creature must be alive to make a footprint. The Bible states that "Everything on dry land that had the breath of life in its nostrils died" (Genesis 7:22). Even dinosaurs would have perished when the strong deep torrents of the Flood overwhelmed them. This explanation is proposed for many dinosaur graveyards in north America, and the cause of their mass extinction.²

Reference

2. Oard, M. J., 1995. Polar dinosaurs and the Genesis Flood. Creation Research Society Quarterly 32(1):47-58.

Post Depositional Erosion

For sediments deposited during the Zenithic phase of the Flood, post-depositional erosion provides clues to the relative timing. Genesis 7:19 records that the waters "rose greatly on the earth, and all the high mountains under the entire heavens were covered." The adjacent figure (part a) illustrates the water covering a continent at the beginning of the Recessive stage. Sediment deposited during the Zenithic phase is shown as horizontal strata beneath the water.

As the present ocean basins deepened during the Recessive stage the waters moved off the continents eroding the sediments selectively. Flow would commence from the edges of the continents as illustrated in part b of the figure while in the interior the water would remain stationary. Sediments near the edges of the continent would be eroded by the fast-flowing water, while sediments under the stationary water would not be disturbed. The surface sediments (deposited later) would be more vulnerable to erosion than deep-sediments (deposited earlier).

The landform emerging when the water receded from the continent as illustrated in part c of the figure would indicate the relative timing of the sediment deposition. Limited erosion (as to the left of the figure) would preserve sediments deposited late in the Zenithic phase. Significant erosion (as to the right of the figure) would expose sediments deposited early in the phase or even during the previous Ascending phase. The presence of erosion indicates that the top of the Zenithic phase is absent.

Sediments deposited during the Abative or Dispersive phases would not display the same degree of post depositional erosion because they were not exposed to power of the receding Flood waters. The strata in rocks deposited earlier, in the Eruptive or Ascending phases, would be exposed to a greater erosion but would be less likely to remain horizontal.

Flat Topped Landforms

The erosive processes associated with the Recessive stage of the Flood would tend to produce flat-topped structures such as plateaus, mesas and buttes as illustrated in the adjacent figure. Where bedding has remained horizontal these geomorphological features would be at the same stratigraphic level. Such structures would occur in Zenithic sediments with the flat-top representing the end of the phase. The above figures illustrate the hydraulic processes operating during the Recessive stage and show how flat-topped structures form in horizontal beds. Flat-topped structures with bedding at the same stratigraphic level would occur in the middle of the continent where the water was stationary initially.

It would be possible for flat-topped structures to form at any time during the Flood whenever tectonic action emptied a depositional basin of water. However, those formed at the top of the Zenithic phase and during the Abative phase would be most widespread and would have the best chance of being preserved. Being deposited late in the Flood, they could not be hydraulically destroyed once the continents were free of water. Those formed during the early phases of the Flood would most likely be disturbed, tilted and eroded during the subsequent tectonic processes.

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