By: Olivia Sherman, News Writer
New research from SFU paleoecologist Dr. Rolf Mathewes reveals evidence for what the geography and plant life on Burnaby Mountain would have looked like over 40-million years ago. When Mathewes was an SFU undergraduate, he discovered ancient plant fossils on Burnaby Mountain with his mentor, Dr. Robert Brooke, whom Mathewes’ most recent paper is dedicated to.
“At the time we collected them, neither I nor Dr. Brooke [ . . . ] knew what they were. Neither one of us was a paleobotanist. So we collected these things [. . . ] and we boxed them up, and put them away,” Mathewes said in an interview with The Peak. “It’s quite a small collection, because it was only collected over a few days when we were just poking around in 1967.”
Mathewes said the fossils he identified were a part of the late Eocene period, or “one of the longest recent geological periods,” that stretched from 54-million years ago to around 34-million years ago. Because the Eocene was pre-Ice Age, it saw a warm climate, and the plants of the period were adapted to tropical temperatures. “We know palms were actually fairly common in this area during the Eocene [ . . . ] in tropical or subtropical conditions.”
The main method Mathewes used to conduct research for his most recent paper was comparing known fossils to current plants and environments. “There are a number of publications where people have studied sites, like the Puget Group near and around Seattle [ . . . ] we had found some close connections between the Puget Group around Seattle and Burnaby Mountain fossils, which wasn’t really known before,” Mathewes explained. “If I find similar fossils, it gives me an idea of where they should fit in the geological time scale. So you do it by association with known fossils and sites that have been better studied, so the ages are almost always an estimate.”
Mathewes is also interested in paleoecology, the science of analyzing historic environments. By looking at environmental conditions of the past, we can predict future conditions. “Plants are the best indicators of climates of the past, because plants are very closely aligned to what the climates are: palm trees are only aligned with tropical conditions, that sort of thing.”
Mathewes explained that plants can also indicate any disturbances they have faced, like fires or earthquakes. “We’ve used pollen spores on coastlines [ . . . ] on previous big earthquake events here, the big ones, and that can be done by looking at sudden submergences, where vegetation changes from upland shrubs to suddenly being intertidal, indicting that the land had shrunk, or the sea-level had suddenly risen.”
Mathewes’ is also focused on palynology, or the study of pollen fossils. “That’s my speciality, actually, working with the things you can’t see [ . . . ] That’s actually the best way to look into the past, because when I’m looking at a slide from 40-million year old rocks at Burnaby Mountain, I’m looking into the past.”
“There’s a lot to be done with the microfossils, but everybody is focused, of course, on the leaf fossils and there’s always two questions, whenever I show somebody a fossil, the first two questions are always: ‘what is it?’ and ‘how old is it?’ And both of those are not easy to answer.”
