From CreationWiki, the encyclopedia of creation science
Fossilization is the process by which plant and animal remains are preserved in sedimentary rock. The Earth is covered in layers of fossils, and this record of history helps us understand what types of organisms that lived in the distant past (i.e. before the flood of Noah).
The study of how living organisms become fossilized in known as taphonomy (Greek for "laws of burial"). Under normal conditions, fossilization will rarely take place, and may best be explained through flood geology mechanisms. Nevertheless, there are two main beliefs regarding the formation of sedimentary rock that contain fossils.
- Uniformitarianism: fossils were buried through uniform rates of erosion and deposition, largely consistent with current rates.
- Catastrophism: fossils were buried quickly by one or more major catastrophes.
Conditions for fossilization
For fossilization to occur, certain conditions must be met. It can only happen after death and normally only affects hard tissues such as shells and bones. In the global cataclysm, organisms that became fossils died either before or after they were buried in the flood sediments. Immediately after death, an organism experiences necrolysis (the decay and breakup up of the organism). Under normal circumstances today the organism suffers destruction by three primary agents--biological, mechanical and chemical (diagenesis)—both before and after they are buried.
Some organism were buried intact quickly and their remains are the best preserved. Others, were buried after they had suffered some decay and breakup. Their remains are usually found in beds of jumbled bone of all types and different species.
- The organism must be buried quickly. For this to happen, the organism normally must die in abnormal conditions such as in a flood, volcano eruption or an earthquake. Otherwise it is near impossible for an animal to be preserved;
- The organism must be kept from normal decay. If the animal is exposed to oxygen or bacteria, they will quickly start to decay;
- The organism must be buried in matter that is leached with mineral-rich waters where carbonates are precipitating. These minerals will replace the original tissue, so that a stone remains in the shape of the original tissue.
From all these examples, a general trend emerges. The best fossilization occurs when there is rapid burial and anoxic conditions to prevent scavenging, no reworking by currents, and diagentic alteration which preserves a fossil rather than destroy it. These conditions are what is expected in models of the Flood.
In 2007, Kirk R. Johnson published a paper showing that plant fossils are the direct result of rapid burial. He uses the example of the Illinois forest, a 3.8 square mile ancient forest. He claims that earthquakes are responsible for the event. To quote him "Well-preserved palaeobotanical remains are therefore direct evidence of rapid burial below the level of destructive processes occurring in soils”.(Johnson; 2007)
Types of Fossilization
Most fossils have been dramatically altered from the original compsition of the specimen, and often their original shape and tetxture are hard to determine unless one has some idea of what took place. The following list comes from this reference.
Exceptional cases: Wolley Mammoth with hard and soft parts preserved; The fossils of the Rancho La Brea tar pits preserved the hard parts including DNA; Amber preserved orgnaisms with many biochemicals still intact.
Buried hard parts--bones or woody tissue--become permeated with groundwater containing dissolved calcium carbonate or silica that flows through porous marrow cavities or wood canals and pores.
Minerals are precipitated in the pores and open spaces encasing the bone or wood within solid rock. In this type of fossilization, new material comes in and joins with the original matter. A dinosaur fossil that has been permineralized has both bone material and rock. This is why soft blood vessel tissue has been found preserved in permineralized T-rex fossils.
Some shells are made of relatively unstable minerals like aragonite. Once the shell is buried aragonite commonly reverts to the more stable form of calcium carbonate--calcite. In other cases, small crystals of calcite recrystalize into larger crystals.
Dissolution and Replacement
As water seeps through shell or bones or other remains, the original material gets dissolved away. A fossil shaped mold may be left behind that is then filled with sediment, in other cases the original material is immediately replaced by some precipitate. Such fossils may not contain any of the original matter.
In this case, most of the volatile organic materials of an organism disperse, leaving a residue of coal-like carbon, sometimes showing the detailed structure of the organism. Such fossils are commonly fish, insects and leaves.
Factors affecting fossilization
Immediately after death an organism experiences necrolysis (death breakup), which is the decay and breakup up of the organism. The primary agents of destruction are biological, mechanical and chemical. The following list comes from this source.
In all environments, scavengers quickly eat and destroy carcasses. In the process, hard parts are broken up and scattered. In subaquious conditions, boring algae or sponges, worms, bryozoans and bacteria efficiently continue the destruction, unless the organism ends up in anoxic waters or sediments. On land, termites, ants, beetles, worms, fungi, and bacteria also destroy organisms in a short time. The key factor that prevents biological destruction is rapid burial.
Winds, waves and water currents are very effective destructive agents especially in shallow water where they have the highest energy. The shape, density, and thickness of an organisms bone, shell or other hard parts determine survival of these parts under mechanical transport. The less mechanical action that an organism experiences, the greater the chances of it being preserved in whole or in part in the fossil record. Fully articulated fossils did not experience mechanical action as has a jumbled bone beds.
After burial, a variety of diagentic changes in the rock, especially metamorphism, can easily destroy shells, for example, and prevent preservation. Aragonitic fossils shells are much more prone to dissolution than calcitic fossils. Original composition and groundwater chemistry are the most important factors in determining whether diagentic changes are likely to alter or dissolve a fossil. These chemical changes can destroy or preserve the fossil
Lagerstatten (mother load) fossils
These unique fossils are found around the world that preserve soft tissues and sometimes even skin texture and color patterns. These are found is places such as the Burgess Shale, The Solnhofen Limestone, the Mazon Creek Beds, the Hunsruck Shale, the Posidonienschiefer of Holzmaden, and the Messel oil shale. From all these examples, several general trend emerge. The best fossilization occurs when there is rapid burial and anoxic conditions to prevent scavenging, no rewoking currents, an little or no diagentic alteration to destroy the fossils.
There are two main beliefs regarding the formation of sedimentary rock; uniformitarianism (organisms were buried slowly and gradually), and catastrophism (organisms were buried during catastrophic conditions).
- Main Article: Uniformitarianism
Uniformitarianism is a guiding principle of origins science that says that the same processes that operate on the universe now, have always operated on the universe in the past, and at the same rates; and that the same laws of physics apply everywhere in the universe.
Uniformitarianism is an important element within modern Geology as it is practiced by evolutionists and embraces the idea of deep time and an old earth. Less well appreciated is its importance as an element in astronomy, in that it also assumes deep time and even infinitely deep time for the entire universe. Uniformitarianism is based on the philosophy of naturalism and was promoted in James Hutton's book "Theory of the Earth" and later expanded upon by Charles Lyell in his three-volume series "Principles of Geology" first published 1830-1833. Charles Darwin took Lyell's books on board the ship HMS Beagle. During that voyage, Lyell's works informed Darwin's thinking about slow biological change known as gradualism.
The word uniformitarianism is defined by the Glossary of Geology as,
|“||the fundamental principle or doctrine that geologic processes and natural laws now operating to modify the Earth's crust have acted in the same regular manner and with essentially the same intensity throughout geologic time, and that past geologic events can be explained by phenomena and forces observable today.||”|
- Main Article: Catastrophism
Those holding to catastrophism assert that most fossilization occurred as a result of a major catastrophe, such as the flood of Noah. In a massive flood of this type, sediments would be torn up in the raging waters, and then laid back down, with organisms buried in them. As the floodwaters receded, these sediments would dry in under a year, leaving the organisms fossilized before they had a chance to be damaged by scavengers or decay under the elements.
In a massive global cataclysm, ecological environments, sediment, and hard rock would be torn up and then deposited in slower and slack water, burying the organisms in layers. Before, during and as floodwaters receded, the sediments would de-water at different rates according to the type of sediment. The organisms could fossilize because they would be within the ideal environments that favor the various types of fossils found
In 1989, there was a massive mortality rate over 98% for urchins through out the Caribbean. Samples show no increase in echinoderm material, hinting that the reefs where incapable of preserving them. Thus fossil urchins and the like should be considered the product of unusual processes. For example catastrophic flooding.
Flood geology is consistent with the known facts about fossils. Uniformitarianism, on the otherhand, posits that the organisms were incidentally buried in unconsolidated sediments which only later became substantial enough to consolidate into sedimentary rock, which violates the known fact that organisms will continue to decay until the sediments become solid rock. Flood geology provides the superior explanation for fossilization.
- ↑ 1.0 1.1 Prothero, Donald. 2004, Bringing Fossils to Life: An Introduction to Paleobiology. Chapter 1
- ↑ Robert Bates and Julia Jackson, Glossary of Geology, 2nd edition, American Geological Institute, 1980, pg. 677
- ↑ Greenstein, B. J. 1989. Mass mortality of the West-Indian echinoid Diadema antillarum (Echinodermata: Echinoidea): a natural experiment in taphonomy. Palaios 4:487-492.
- Kirk R. Johnson, “Paleobotany: Forests frozen in time,” Nature 447, 786-787 (14 June 2007) | doi:10.1038/447786a.