Piecing Together a Picture of Prehistoric Plants

A new field site discovered in the Transantarctic Mountains preserves evidence for a large lake that existed 250 million years ago. Thinly bedded siltstones deposited in the lake contain fossils of glossopteris flora--a plant group that lived at the time across all the continents forming the Gondwana supercontinent.

When glossopteris inhabited this lake area it was located at a very high latitude. The positioning suggests the plants endured four months of total darkness and four months of complete daylight. To cope with the unique environment glossopteris evolved strategies to survive. The plant fossils provide the only glimpse of how these plants lived and thrived because no other place on Earth provides a similar set of environmental factors.

A graduate student working with University of Kansas researcher Edith Taylor discovered Skaar Ridge, the new Permian Age research site. This site records the seasonal change between fall and spring at high latitudes that were much warmer than conditions today. Based on the patterns on the fossil leaf surfaces some of the fall layers had leaves that were broken up by fungi and eaten by animals.

The research group is attempting to develop a more accurate picture of the total flora present at high latitudes across the Permian-Triassic boundary--rock formations that contain clues about life before the most extensive extinction event on Earth occurred.