Tiny vertabrate teeth help prof build
GEOLOGIC CLOCK

By Garth Boucher

he teeth of a primitive eel-like vertebrate called the conodont are indirectly helping pinpoint the existence of oil and gas deposits in Western Canada.

The teeth of the conodont, which appeared in earth’s warm oceans 500 million years ago, are the focus of research by Dr. Charles Henderson, a University of Calgary micropale-ontologist. Fossils of this extinct, soft-bodied animal are rare because only hard parts like teeth typically survive the fossilization process.
The study of these ancient teeth is part of a large movement within the geological community to piece together a cohesive and detailed geologic timeline of the earth. In effect a geologic clock is being built.

While Henderson’s interest in the conodont is focused on the creation of this geologic clock, research in the animal is also of interest to those in the oil and gas industry.

“In one sense, this pursuit can be viewed as a highly academic endeavour. But there are numerous oil and gas deposits in Western Canada. A clearer picture of the geologic timeline will aid us in more efficiently finding these resources.” Indeed, a substantial portion of Henderson’s funding comes from oil companies, as well as NSERC.

Conodonts are useful to the construction of this geologic clock because they provide a means of comparing rocks from different locations across the globe.
“ When you’re looking at Mount Rundle in Banff, and your eye follows a distinct layer of rock, you’re looking at an ancient ocean bed.” Henderson explains. “The problem is figuring out how to connect these beds in the Canadian Rockies with their counterparts in other places around the world. This is where conodonts come in.”

Remarkably durable and prolific, the four-centimetre conodont survived the oceans for upwards of 300 million years. Today, their millimetre-sized teeth are abundant in fossil beds worldwide. This is crucial because it means paleontologists have an excellent record of their evolution. In the parlance of paleontology, conodonts are excellent “index fossils” in the sense that the record of their physical evolution provides a reliable reference framework against which the surrounding rock can be compared and dated. Given two limestone samples from different locations, the presence of conodonts with similar physical features is a good indication that the samples are of a similar age.

Henderson is specifically interested in the Permian Period (299-252 million years ago), a period which is further divided into nine ages. The period culminated in the earth’s greatest extinction event.

As Chair of the Subcommission on Permian Stratigraphy (SPS), he is responsible for a group of geologists whose job is to identify and agree upon those conodonts that will act as “reference points” in the rock serving to define the boundaries between the ages.

In December 2003, Henderson and the SPS gathered in China to finalize and vote
on a proposal outlining the details of one such Permian age boundary called the “Wuchiapingian-Changhsingian.” The proposal now awaits ratification by the International Commission on Stratigraphy (ICS), the body overseeing the construction of the “geologic clock.”