Geographer traces changes to landscape
By Andris Petersens, SPARK Correspondent

Most of mainland Canada was covered with a large continental ice sheet while Newfoundland had its own smaller ice cap.  As the climate slowly warmed, the ice melted and retreated. Today scientists are interested in the dynamics of ice retreat and climate changes to find out how large ice masses such as the Antarctic or Greenland ice sheets might respond to future climate warming.

“Sea level changes in Newfoundland are mostly the legacy of the last glaciation. The source of water for these large ice sheets is the oceans. So, as ice sheets grow, ocean volume decreases and sea levels fall everywhere,” said Dr. Bell. “At high latitudes, however, the weight of the ice sheets cause the Earth’s crust to sink, causing local sea levels around the ice sheet to be higher. Later, as the ice sheet melts, the crust rebounds slowly. My work looks at the pattern, magnitude and timing of these sea level changes around the province.”

One way to document changes in sea level is to examine marine features and sediments that relate to former shorelines, and then to date the fossil shells, driftwood and whalebone found in them.

On the Northern Peninsula, the sea level at the end of the last glaciation was 140-150 metres higher than it is today. Much of the coastal lowlands was below sea level. Gradually, the land has emerged from the sea exposing islands and peninsulas. Meanwhile, for the remainder of the island, the sea has been submerging the land, drowning islands and eroding the coastlines. In such places as Stephenville, Port-aux-Basques and Burgeo, the sea has risen 30 metres or so in the last 10,000 years.

Dr. Bell, together with Dr. Joyce MacPherson from the Geography Department, explores how the vegetation has changed since the ice sheets retreated