HOME PAGE
MASTER INDEX
ARTICLES PAGE
GEOLOGICAL AGES

Article from the Backbenders Gazette of November, 2001
(Third Place winner in Adult Advanced Articles 2002 competition
American Federation of Mineralogical Societies)

SHOWING YOUR AGE
© 2001 Terrell William "Terry" Proctor, J.D.

How old is the fossil you found on your last field trip? How old is the Earth? How old is the Universe? You undoubtedly have read different accounts on these things, but it may be confusing to know the basis for the things you have read.

Regardless of which version of the Old Testament Bible you read, the very first Chapter and verse starts with something like "In the beginning" and then the scripture goes on to discuss that God created the heavens and the earth. All versions give the order as: the division between light and darkness; the division of the firmament (land and sky); the division of the land and water; creation of vegetation; creation of the sea and land animals; creation of the domestic animals; and finally creation of man and woman. There is not much disagreement between science and religion on the order of the creation of things or how they came about, whether you are a religious person or not. However, there is a lot of disagreement as to the time it took and the age of things.

To my understanding most Christians, Jews, Moslems and virtually all other religions which have any view on the age of the Earth and the Universe, there is not much of a problem with the scientifically established age of the Earth and Universe. To my understanding, the three major religions which believe in the Old Testament Bible, i.e. Jews, most Christians and Moslems, do not perceive of a conflict in the story of the Creation in the Old Testament Bible and that derived from science as to the age of creation.

The purported scientifically determined age of the Universe and the Earth has been extended dramatically in the past few several hundred years. Most earth scientists currently contend that the Earth is about 4,600,000,000 (4.6 billion) years old and the Universe is about 13,000,000,000 (13 billion) years old. The Hubble Telescope, satellite and other increases in the field of astronomy in recent years has greatly enhanced our ability to know about our Universe and its age. This includes newer terms and scientific conditions of things like "red shift", "doppler effect", gravitational pull of light waves by unseen dark objects, and many other fascinating things.

Some Christians, who are referred to as "sudden creationists" (and sometimes refer to themselves just as "creationists") believe something quite different. They believe that the Earth is 6,005 years old this year. In 1654 Archbishop Usher of Ireland declared that the Earth was created at 9:00 A.M. on October 26, 4004 B.C. For several hundred years, this was the accepted age of the Earth.

However, since 1654, the age of the Earth has been updated many times with new scientific data, tests and analysis. New findings of fossils, artifacts, minerals and changes in the Earth and its components, has made 6,005 years old for the Earth seem to be an incomprehensively short time for everything this planet has been through. Scientific research, tests, findings and studies have led to the conclusion that such a short time period for all that has happened on Earth, is simply impossible.

Although I consider myself active in the area of religion, it is not my purpose to teach or debate religion or to take issue with any group, but just to set out that there are differences in beliefs on the age of the Earth and the Universe, for different reasons, one of which is a religious basis. There is quite a bit of data to support that science has done a great deal to confirm and support religious beliefs held by many Christians, Jews and Islamic people.

While many rockhounds understand that science has ways of establishing dates of fossils, minerals and artifacts, there remains a lot of fuzziness over just how this is done. The question which often comes up "just how do scientists tell the age of things?". I don't profess to be an expert, but I do understand some things about scientific age determination (possibly just enough to get myself in trouble even discussing it). Therefore, for the benefit of those who may not understand quite as much as I have learned, from those who know a great deal more than I do, I will attempt to help explain.

There is not just one test for testing the age of certain artifacts, minerals, fossils and other things which one wishes to date (called "things" in this article), regardless of what the thing may be and how old it may be. There are many tests and more are being discovered. Additional means of testing is helpful, as it helps to correlate and corroborated other tests, lending authenticity to the various tests. In some cases, these newer tests may throw doubt on earlier testing, or show errors when tests do not support each other. This may mean getting rid of erroneous testing methods and/or help create more accurate tests by correcting procedures or correlation of results.

A great deal of the testing done for age of "things" is by radiometric dating. Many of today's tests are based upon what is called a "half life period". A half life period is the period of time during which half of a radioactive substance breaks down to a non-radioactive substance. The "half life" is the number of years which it takes half of the radioactive element to decay into the stable element which is the companion element. The initial element is called the "radioactive parent" and the decayed element is called the "stable daughter". The analogy has often been used to explain the "half life" period as if it were a frog which each time it jumped, the frog jumped half of the remaining distance from a given location toward a wall. The distance each time is only half of what it was before, but the frog will never get to the wall as it always has half the remaining distance left after each jump.

To give you some examples of half lives of radioactive elements, here are six showing the parent, daughter and half life (in length of half life order):

So how does this translate to the age which can be tested using these elements?

Carbon 14 to nitrogen 14 = 0 to 40,000 years or using accelerator mass spectrometry = 0 to 50,000 years to maybe 70,000 years, (on minerals, shell, wood, bone, teeth, water)

Uranium series disequilibrium = 0 to 400,000 years
(on minerals, shell, bone, teeth, coral)

Potassium to argon = 10,000 to 3,000,000,000 years
(on minerals)

Uranium to lead = 1,000,000 to 4,500,000,000
(on minerals)

Rubidium to strontium = 60,000,000 to 4,500,000,000
(on minerals)

For an example, let us use carbon 14 to nitrogen 14. All atoms of every chemical element contain sub-atomic particles which comprise the atom. I won't go into all of the sub-atomic particles which have been discovered or hypothesized or believed to have been detected today such as positrons, muons, prions and others. For our purposes, we will concern ourselves with three basic components of an atom. The nucleus of any atom contains at least one proton, which carries a positive charge. With the exception of hydrogen, the nucleus of any atom contains at least one neutron which carries a neutral charge. Every atom also has at least one electron which circles the nucleus, but we need not concern ourselves with electrons at the moment.

Of importance in time dating is that a stable nucleus has an even number of protons and neutrons. Carbon 12 (regular carbon) has six protons and six neutrons. The six protons and six neutrons are added together, i.e. 6+6 = 12 and the element is called carbon 12, which is the common form of carbon. Carbon 12 is therefore stable and in balance.

When the number of neutrons in the nucleus of an atom are not the same as the number of protons, the substance is called an isotope. A carbon 14 isotope has 8 neutrons and 6 protons in its nucleus and the isotope is therefore an unstable atom and radioactive. This isotope occurs when a nitrogen atom is bombarded in space with subatomic particles from the Sun which change the nitrogen 14 into carbon 14. In the atmosphere the radioactive carbon 14 combines with oxygen to form radioactive carbon dioxide. This radioactive carbon dioxide is absorbed by plants in their photosynthesis process and from there goes into the food chain and carbon cycle.

All living things contain a constant ratio of carbon 14 to carbon 12 which is 1 part carbon 14 to 1,000,000,000,000 parts of carbon 12. At death, a formerly living thing (plant, animal or other) no longer accumulates any additional carbon 14 and the carbon 14 loses the extra two protons as it decays into carbon 12. This process is what sets up the half life of that element as being 5,730 years. Carbon 14 testing is essentially good only for archaeology and for dating up into the Pleistocene age.

There are other non-radioactive means to determine the age of a "thing". Here are some, but certainly not all, examples with the little I know, if anything, about each:

"Dendrochronology" which is the study of tree rings to determine the age of a tree and therefore those things around the tree and related to the tree's age. This is accurate only from 0 to about 12,000 years, which is an extremely short time in dating.

"Lichenometry" is the study of lichens which is even shorter and ranges from about 100 years to only about 9,000 years.

"Geomagnetic polarity" The North Pole has wandered about the top of the Earth for millions of years. Igneous rocks sometimes have some form of iron type minerals which polarize as they cool after being expelled from the Earth through volcanos or other means. As the igneous rock cools, the iron mineral polarize on the then current North Pole and are fixed for all time on that direction (subject to movements of the rock by other dynamic forces of the Earth later). Therefore, once the age of a given rock is determined, and the polarization is determined, then any other rock in which the iron mineralization points to the same North should be the same age as that already determined. Needless to say, the location of the rock being tested has to be carefully secured in order to determine where the iron mineral is pointing.

"Amino acid racemization" This is a procedure for dating by examining the proteins preserved in a formerly living "thing". The building blocks of proteins are amino acids and they can take either a left handed or right handed form. Left handed is the overwhelming favorite in nature, for reasons unknown. However, these can flip to the other form and this process is speeded up by heat. Adjustments must be done for known climatic changes over time, but in tests these results correlated with other methods.

"Obsidian hydration" Obsidian is natural glass and the amount of water in the glass is used in another test. There are a number of other means of testing age, not addressed here.

Not every substance can be tested for its age directly, but some age checking must be interpolated by other means. For instance a clay pot found in the ground may not be able to be tested by most methods of aging to determine its age, because it was never alive. However, if the pot has food particles still inside or there are other organic substances around which can be tested, then the age of the pot can be determined with reasonable certainty.

Another term you should know is "index fossils". One category of index fossils often used are the "foraminiferas". These are very small single-celled, amoeba-like, protozoans which form a shell (or test) from calcium carbonate (CaCO3) or from cemented grains of sand or other material such as sponge spicules. These are very small animals and the largest reach size up to only a few centimeters but most adults are only 1/5 to 1 millimeter, about the size of a pin head.

They are marine animals and found at every level in the oceans of the world in huge quantities and have been for many millions of years. Other index fossils are bivalves, gastropods and other marine and fresh water animals and plants.

Index fossils are generally called that because they are so widely disbursed at certain ages in the history of the Earth and so readily recognized. Therefore when they are found, you can date a formation you are in, by knowing the age of "index fossils" in that formation.

There is so much more which could be covered, but let me close with a few observations. Things do wind up in the wrong age on occasions, because the cataclysmic forces of nature are constantly upending formations, pushing them up and down, and waters wash things down to other locations, to mention only a few. Therefore, it takes care to determine that the "thing" you want to obtain a date upon is located where it really came to rest at death and has not been a vagabond from another age, heaved about by plate tectonics, rivers or other natural forces to come to rest in an older or younger formation.

Another observation is that over time some tests have been found to be unreliable and/or have needed clarification and correction. That is what science is all about. Science is to be constantly challenged and tested so that the known results become more accurate with time and more dependable, with the bad results jettisoned. Religion, on the other hand, is taken on faith and physical proof is not something which a believer seeks or would consider to prove or disprove a belief. Fortunately many folks do not find a conflict between their strong religious beliefs and the factual conclusions which science has used to determine the age of the Universe, the Earth and the "things" you and I find on our field trips.

I extend my appreciation to the following sources, which are some of those which I have read over the years and/or used currently in preparation of this article.

National Geographic, September 2001 issue "How Old Is It? Solving the Riddle of Ages"

Georgia Perimeter College's Georgia Geoscience Online, September 9, 2001 located at: http://www.dc.peachnet.edu/~pgore/geology/geo102/age.htm and/or http://www.dc.peachnet.edu/~pgore/geology/geo102/radioa.htm (NOTE July, 2003: this website is apparently no longer good)

Institute of Geological & Nuclear Science, Ltd., September 9, 2001 located at: http://www.gns.cri.nz/earthhist (New Zealand firm) {current note: this site is no longer on line apparently}

Material supplied over several years by Geochron Laboratories, Krueger Enterprises, Inc., 711 Concord Avenue, Cambridge, Massachusetts 02138 (617) 876-3691 or http://www.geochronlabs.com

My special thanks to Geochron Laboratories who for a number of years have supplied members of the Houston Gem & Mineral Society with plastic cards showing the "Geological Time Scale" as adapted from DNAG, 1983.

Contact: Terrell William "Terry" Proctor, J.D. c/o T. W. Proctor & Associates
630 Uvalde Road, Houston, Texas 77015-3766
Phone: 713) 453-8338 FAX (713) 453-3232 Email: auraman@swbell.net
Other Websites: https://terryco.us and http://www.terrylaw.us.