Polystrate Fossils (Sidebar 5)

Polystrate fossils are fossils which span more than one layer of strata (i.e. a fossil in a vertical orientation that cuts through the horizontal layers of rocks); types of polystrate fossils commonly found include trees, stumps, reeds, and occasionally animal bodies. Many polystrate trees have been found in coal beds, and other areas, like Specimen Ridge in Yellowstone National Park, have "forests" of petrified trees and stumps in an upright position.

Evolutionary interpretation of polystrate trees:
The evolutionary, uniformitarian explanation for petrified forests (like at Specimen Ridge) would be as follows: the lowest level of trees represents the most ancient soil level and forest, and each level above represents another forest. The layers consist of mature trees with up to 1,000 growth rings. In the first forest, the trees were growing in their natural habitat, when they were covered with volcanic ash and other debris. Over time, the trees petrified, and the surface ash turned to volcanic clay, and to a soil layer. Another forest of trees grew up, matured, and was also buried by volcanic ash. According to uniformitarian geologists, this whole cycle has occurred 27 times on Specimen Ridge, and over 50 times at Specimen Creek. At Specimen Creek Petrified Forest, long age geologists have interpreted the petrified trees to represent at least 50 different forests that probably took from 30,000 to 40,000 years to deposit. After deposition, burial, and petrification of the last forest, erosion of the cliff by uniformitarian processes would have taken longer than 40,000 years.

Some characteristics of the petrified forests in Yellowstone which are atypical of a forest:

1. The large roots of many trees are frequently broken, though the small ones are usually intact. Most of the trees have no bark or limbs. 2. The levels, which are supposed to be equivalent to distinct, separate forests, overlap in places. For example, the tip of a tree branch in a lower level protrudes into the stump level of the next "forest." In one specific location, the succeeding level contains trees that have 500 growth rings, yet an exposed branch from the level below has no evidence of decay at all (Coffin, 1983). This is difficult to explain if the branch was, indeed, exposed for 500 years. 3. The petrified trees in Yellowstone (both vertical and horizontal) tend to be arranged in the same orientation. A common orientation has not been found in any living forest. 4. Including pollen species, there are representatives of over 200 different types of plants in the petrified forests. The plant types range from temperate to exotic and tropical, and from semi-desert to rain forest types. 5. Many of the tree layers have organic material with the tree roots, and this has been interpreted as soil layers. However, the organic material is not consistent with a soil layer. First, some things, like pinecones and pollen, are missing or are not abundant enough. Also found in forest soil layers are many, many rootlets, however, in the organic layers of the petrified forests, rootlets are very rare. Since most of the petrified trees are Sequoia, there should be many pine needles and some pinecones around the trunks. Instead there are more broad leaves than pine needles. A second characteristic inconsistent with soil layers is that the leaves and needles are all equally well preserved with no evidence of decay to humus compost. In a modern forest, leaf litter decays to humus and it is covered by more current leaf litter. Third, the organic layers are not thick enough to be soil layers. The average thickness is 3 cm, and the maximum thickness is only 15 cm. Some trees have no organic layer with their roots at all.

Flood model for the deposition of the petrified forests based on observations at Spirit Lake:
The eruption of Mt. St. Helens resulted in the deposition of one million trees in Spirit Lake. The original estimated proportion of floating trees was 40% Douglas fir, 22% Noble fir, 12% Western Hemlock, 12% Pacific Silver fir, 10% Western Red Cedar, 2% Alaska Yellow Cedar, and 2% others. As the logs floated, bumping and rubbing caused the bark to fall off. Ten years after the eruption, half of the logs had sunk to the bottom. At this point the percent of Douglas fir that floated on the surface had risen to 75% because other types of trees absorbed more water and sank to the bottom. From 1980 to 1985, all the Noble fir logs (approximately 200,000) became water-logged and sank to the bottom. From 1985 to 1990, the dominant type of log to be deposited was Western Hemlock, and about 100,000 logs fell to the bottom. Since 1990, the most abundant log to be deposited on the bottom has been Douglas fir (Austin et al, 1997). Studies with sonar and scuba have demonstrated that many of the logs are floating upright with the root end weighing them down. Many logs have fallen to the bottom of the lake in an upright position and are standing in three feet of debris. If Spirit Lake were to be quickly filled with volcanic debris, and all the strata fossilized, it might seem that a forest of Noble fir grew up, was covered by volcanic ash, petrified, and was followed hundreds of years later by a forest of Western Hemlock which was covered by volcanic ash, petrified and was followed hundreds of years later by a forest of Douglas fir, which was buried by volcanic ash and petrified. We might suppose that all this took hundreds of years, but because we observed it, we know that it took less than two decades.

A similar incident may have been responsible for the layers of petrified forests in Yellowstone National Park and in other locations. The catastrophic processes during Noah's flood would have ripped up millions of trees, breaking them off by the root, and carrying them in mats of vegetation, where they would bump together and lose their bark. The vegetation mats would likely collect specimens from varying ecosystems. As the waters prevailed on the earth, organic debris would settle to the bottom in sorted layers. Water sorting could also explain the similar orientation of the trees. Trees would eventually become water-logged in their root ends and many would float in a vertical position, and soon settle to the bottom, standing upright. A subsequent volcanic eruption would cover the trees on the ground level, and other organic debris and trees would sink into the new layer of volcanic ash. This process could have occurred and been repeated many times in the turbulence of the Flood of Noah's time.

Impact Articles: The Yellowstone Petrified Forests

References

Morris, John. "Geologic Evidences for a Young Earth," The Young Earth. Master Books, Colorado Springs, CO. 1994. Austin, Lumsden, Morris, and Vardiman. "Geologic Evidence for Catasrophism in Mt. St. Helen," Mount Saint Helens Tour Guidebook. Institute for Creation Research, Santee, CA. 1997. Coffin, Harold. "The Yellowstone Petrified Forests," Origin by Design. Review and Herald Publishing Association, Hagerstown, MD. 1983.