Lakehead professor studied 1.4 billion-year-old rocks near Dorion to determine abundance of life on Earth
July 18, 2018 – Thunder Bay, ON
A Lakehead University Geology professor is part of a team of researchers who collaborated on an article exploring oxygen and life on Earth that Nature.com will release soon.
The article describes how the researchers used gypsum east of Thunder Bay to determine if there was as much life on Earth approximately one billion, four hundred million years ago as there is now.
“The group of scientists I worked with devised a way to determine how abundant life was in the past compared to today,” Dr. Phil Fralick said.
“Oxygen is a key element in the life processes of both plants and animals. It is given off when plants photosynthesize and animals breathe it in to burn calories in their bodies.”
Oxygen occurs as three isotopes – atoms with the same number of protons but different numbers of neutrons. The ratio of each of these isotopes to one another is constant on Earth, but animals and plants interacting with oxygen change the isotope ratios in the atmosphere, Dr. Fralick said.
“The more interaction there is with life the more the ratios change. So, if we could measure the isotope ratios of oxygen at a time in the past we could compare the results to today's atmosphere and see if life on Earth was more or less abundant. In fact, we can sample the ancient atmosphere,” he said.
The mineral gypsum, the white stuff in wallboard, comes out of solution in the ocean and saline lakes when the water evaporates and gypsum has oxygen in it that had been in the atmosphere.
“There are old dried-up saline lake deposits to the east of Thunder Bay. The gypsum is in the red rocks from Dorion to past Kama Hill. We sampled this gypsum and analyzed oxygen's isotopic ratios in it. We know that these rocks are 1,400,000,000 years old, that is one third of the way back to the beginning of the Earth,” he said.
“The most advanced life form at the time were just one celled organisms like bacteria. The oxygen isotopes told us that life on Earth was far less abundant than today, but it was operating on Earth,” Dr. Fralick said.
The paper, called Triple oxygen isotope evidence for limited mid-Proterozoic primary production, is scheduled for Advance Online Publication (AOP) on www.nature.com at 1 pm Eastern Time today (Wednesday, July 18).
Peter W. Crockford1,2,3*, Justin Hayles4,5, Huiming Bao5,6, Noah J. Planavsky7, Andrey Bekker8, Philip W. Fralick9, Galen P. Halverson1, Thi Hao Bui1, Yongbo Peng5, and Boswell A. Wing10
1McGill University 3450 University
Street Montreal, QC H3A0E8, Canada
2¬Weizmann Institute of Science, Rehovot 76100, Israel
3Princeton University, Princeton New Jersey 08544, USA
4Rice University 6100 Main St. Houston, TX 77005, USA
5Louisiana State University Howe Russel Building, Baton Rouge, LA 70803, USA
6School of Earth & Space Sciences, Peking University, Beijing 100871, China
7Yale University 210 Whitney Ave., New Haven CT 06511, USA
8University of California Riverside, 900 University Ave. Riverside CA 92521, USA
9Lakehead University. 955 Oliver Rd. Thunder Bay Ontario, P7B 5E1, Canada
10University of Colorado Boulder, UCB 399, Boulder, Colorado 80309, USA