Four billion year-old rocks provide clues about how continents formed
Friday, May 30, 2014, 3:33 PM - University of Alberta geochemistry student Jesse Reimink has discovered a four-billion year old chunk of an ancient protocontinent that holds important information on how our planet's early landscape was formed.
According to the university, the ancient rock could help us understand how the early continents formed.
Modern continents form as tectonic plates shift, sending magma to rise to the surface through a process called subduction – but it’s unclear whether or not plate tectonics existed billions of years ago.
Some scientists believe the first continents formed in the ocean as liquid magma rose from the Earth, and then cooled, creating a thick crust.
Working with Tom Chacko, Reimink spent nearly three years collecting rock samples in the Nortwest Territories at a site that has been producing some of the planet's oldest rocks since the 1980s.
Many of the ancient finds to date have been between 3.6 and 4 billion years old. Some have been well enough preserved to show their geochemical characteristics which demonstrate, according to Reimink, that early continent formation was similar to the way present-day Ireland was formed.
“This provides the first physical evidence that a setting similar to modern Iceland was present on the early Earth,” he says in a statement.
The complete study can be found online at Nature Geoscience.