Tree Ring Dating

Most everyone knows that trees have rings. Each year, a tree grows a new ring. The age of a tree typically can be determined by counting the rings. I bring this up because counting tree rings proves that the earth must be more than 11,000 years old.

Now it’s a little more complicated than I have implied (but only a little). The oldest known living tree is 5065 years old. This fact alone places into question the young-earth chronology in which a global flood devastated the earth only 4360 years ago.

Creative Commons Attribution-ShareAlike 2.0 Generic License by Albert Bridge

Each ring consists of both light and dark wood and corresponds to one year of growth.

Tree rings carry information. Each ring contains two types of wood. The first type, which forms at the beginning of the growing season, is called the early wood. It is less dense and is lighter in color. The second type, which forms at the end of the growing season, is called the late wood. It is denser and is darker in color. The thickness of the early wood and the late wood formed in a given year is an indication of the nature of the growing season in that year. A long, warm growing season with plenty of rainfall produces a wide ring. A cold growing season or one with little rainfall produces a narrow ring.

Creative Commons Attribution 2.0 Generic License by ilya_ktsn

Bristlecone pines such as this one include the oldest known living trees.

Now a warm year for one tree is also a warm year for other trees in the same area. As a result, one would expect a correspondence between the widths of the rings of different trees in the same area. This is, in fact, the case. Trees of the same type living in the same area at the same time show the same pattern of wide and narrow rings.

Suppose that one were to find a piece of fossilized wood of unknown age. It may be possible to match the rings of that wood to the rings of living trees of the same type in the same area and hence to determine the age of the wood. Now suppose that a reliable match is determined but that the fossilized wood also has rings that were formed before the earliest ring of the living tree. The record of tree rings then encompasses a span of time longer than the age of the oldest living tree.

This process has been carried out by scientists many times, resulting in continuous tree ring records that, in some cases, stretch much farther back through time than the age of the oldest living tree. The longest continuous tree ring record of this sort spans more than 11,000 years.

At this point, I might typically answer some objections or address opposing arguments. However, there really is nothing in that respect to be done because Answers in Genesis has already done it. They have analyzed this issue and have affirmed that the rings are indeed correctly cross-matched and that the bristlecone pines are not capable of producing more than one ring per year.

So not only do we have direct evidence that trees have been growing on the earth for more than 11,000 years, but we also have evidence concerning the nature of those years and even the amount of carbon-14 present in the atmosphere in each year—which will be the subject of the next post.

Advertisements

Rocks of the Grand Canyon

I’m not sure whether a debate about the age of the earth has taken place in recent times without any reference being made to the Grand Canyon. Most scientists claim that it must have taken many years to form, but those who believe in a young earth claim that it could have been formed quickly. These people point primarily to two known facts: Large floods can deposit layers of sediment, and canyons can form quickly. Using this information, they conclude that a global flood could have created all (or most) of the rock layers seen in the canyon and that a large flash flood caused by a dam bursting shortly after the flood could have carved out the canyon itself. Does this explanation hold water (pun intended)? What are the facts concerning the Grand Canyon, and are they compatible with formation by a global flood? Today I will address the formation of the rock layers seen in the Grand Canyon, and next time I will address the formation of the canyon itself.

Nobody disputes that floods can and often do deposit layers of sediment. However, a more specific question is warranted: Could the particular types and sequence of rock layers found in the Grand Canyon have been formed by a single flood event? This is a question that I have never heard young-earth creationists address.

The young-earth creationists typically point out that if you shake up a jar of muddy water and let it settle, it will form layers according to the densities of the suspended particles. They claim that this is how rock layers formed in the flood. It is true that floods can form layers in this manner. The coarsest sediments end up on the bottom, and the finest sediments end up on the top. However, this is not what we observe in the layers of rock found in the Grand Canyon area.

You see, the top layer of rock in the Grand Canyon area is limestone (#1 in the diagram). Beneath that is a layer of sandstone (#3). Beneath the sandstone is siltstone (#4), and beneath the siltstone is more limestone (#7). If these layers were all formed at the same time by settling of particles after a global flood, then we should expect the sand to have settled before the silt. It should not be possible in this context for a sandstone layer to form on top of a siltstone layer. Also, it should not be possible for these to be sandwiched between different layers of limestone.

Limestone is a type of rock that can form only in a marine environment, and both layers of limestone (#1 and #7) contain numerous marine fossils. Sandstone can be formed either on land or underwater. However, the sandstone (#4) in between these two layers of limestone could not possibly have formed underwater. It contains no fossils of marine organisms. Also, it contains numerous fossil tracks, including reptile tracks and also tracks from small arthropods such as centipedes and spiders. It also contains raindrop impressions. These cannot be formed underwater.

So the evidence clearly points to this: The land was submerged under water for some time. At some point after this, it became a sandy desert. After this, it was again submerged under water for a long enough time to form several hundred feet of additional limestone. I simply cannot figure out how this can be explained by a single global flood. I have searched the internet and cannot find even a single source that attempts to explain this.

If you can explain to me how the specific layers of rock found in the Grand Canyon area could have formed in the observed sequence by a global flood, then please do. Really, I mean it. I’m dying to understand this.