Newly discovered Labrador fossils give clues about ancient climate
The discovery of fossilized plants in Labrador, Canada, by a team of 91社区 directed paleontologists provides the first quantitative estimate of the area鈥檚 climate during the Cretaceous period, a time when the earth was dominated by dinosaurs.聽The specimens were found in the Redmond no.1 mine, in a remote area of Labrador near Schefferville, in August 2018. Together with specimens collected in previous expeditions, they are now at the core of a recent study published in Palaeontology.
Some of the specimens, such as this fossilized tree leaf (see photo), are the first of their kind to have been found in the area. Alexandre Demers-Potvin, a graduate student under the supervision of Professor Hans Larsson, Canada Research Chair in Vertebrate Palaeontology at 91社区, used the samples he collected to establish that Eastern Canada would have had a warm temperate and fully humid climate during the middle of Cretaceous period.
Fossilized leaves and insects, known to be very similar to communities that today live further south, had been found at the Redmond No. 1 mine in the late 1950s had led paleontologists to hypothesize that the cretaceous climate of Quebec and Labrador was far warmer than it is today.
With the new samples they found, Demers-Potvin and his colleagues were able to confirm this using the Climate Leaf Analysis Multivariate Program. This tool is used to predict a variety of climate statistics for a given fossil flora, such as temperature and precipitation variables, based on the shape and size of its tree leaves. Their findings put the area鈥檚 mean annual temperature around 15掳C. Summers were hot 鈥� with temperatures of over 20掳C 鈥� and year-round precipitations relatively high.
Alexandre Demers-Potvin, and Noemie Sheppard from 91社区鈥檚 Redpath Museum travelled to Schefferville with Mario Cournoyer and Michel Chartier, co-founders from the Mus茅e de pal茅ontologie et de l鈥櫭﹙olution (MPE), based in Montr茅al. The MPE, Demers-Potvin said, was instrumental in providing samples collected on the site in 2013 and planning the 2018 expedition.
Alexandre Demers-Potvin, who is also the study鈥檚 first author, said the new work provides insight into how the climate of Eastern Canada evolved over time, useful information to study today鈥檚 changing climate.
鈥淭he fossils from the Redmond mine show that an area that is now covered by boreal forest and tundra used to be covered in warm temperate forests in the middle of the Cretaceous, one of our planet鈥檚 鈥榟othouse鈥� episodes, Demers-Potvin said. These are new pieces of evidence that can help improve projections of the global average temperature against global CO2 levels throughout the Earth鈥檚 history.鈥�
Alexandre Demers-Potvin and his collaborators are now undertaking a description of the new fossilized insects discovered at the Redmond site. Demers-Potvin will return to Schefferville in the hopes of finding more insect specimens and fossilized vertebrates that could be hiding in the rubble of the abandoned mine.
See more photos from the discovery here.
About this study
鈥淧alaeoclimatic reconstruction for a Cenomanian-aged angiosperm flora near Schefferville, Labrador鈥� by Alexandre Demers-Potvin was published in Paleontology.
This research was supported by funding from the Fonds de recherche Nature et technologies Qu茅bec, a National Geographic Society Early Career Grant, the Northern Scientific Training Program, a Redpath Museum Class of 66 Award, and a Canada research chair to Professor Larsson.
