Excavations near Macquarie Harbor in western Tasmania have uncovered the remains of a 53-million-year-old "polar forest," revealing a wealth of tropical plant fossils, including two previously unknown conifer species.
This discovery provides valuable insights into the evolution of southern rainforests during the Eocene epoch, a period characterized by significantly higher global temperatures. According to Miriam Slodownik, a paleobotanist from the University of Adelaide, "This discovery offers rare insights into a time when global temperatures were much higher than today."
During the Eocene, Tasmania was situated closer to the South Pole, yet a warm global climate allowed lush forests to thrive in these regions. The findings suggest that as the continents separated, tropical plants from the polar forest migrated north, contributing to the rainforests we see today.
Researchers excavated over 400 plant fossils, identifying 12 different species, including relatives of iconic Australian trees such as Kauri and Wollemi pines. Notably, two extinct species were named in the Aboriginal language of Tasmania, honoring the land's Indigenous inhabitants.
The analyses indicate how these plants adapted to thrive in warm, ice-free conditions, even amidst extreme seasonal changes near the polar circle. As the Earth cooled and polar regions became glaciated, the landmass now known as Australia drifted north, leading to the evolution of the diverse flora found in Australia today.
Overall, these ancient plant fossils not only highlight the diversity of the Tasmanian forest but also reflect broader climatic and tectonic changes that have shaped our planet over millions of years.