Rizo Collected Ancient Rocks from One of the Oldest Terrains on Earth

Hanika Rizo
DTM Postdoc Hanika Rizo spots a polar bear while doing fieldwork in the beautiful Canadian province of Labrador. (Credit: Hanika Rizo, DTM, 2014)
Thursday, August 28, 2014 

While in pursuit of her research about early Earth’s evolution, DTM Postdoc Hanika Rizo collected rock samples from an ancient terrain in the polar bear populated Canadian province of Northern Labrador this summer.

In collaboration with DTM Acting Director, Rick Carlson, and former postdoctoral fellow Jonathan O’Neil (University of Ottawa), Rizo gathered rock samples of both volcanic and sedimentary origins that could shed a new light on the geological processes that shaped our planet. 

Ancient terrains (older than 3.6 billion years), like the Saglek-Hebron area in Northern Labrador where Rizo conducted her research, are extremely rare.

Unlike most of Earth’s old crust, erosion, volcanism, meteorite impacts and crustal recycling have not destroyed this region. This makes it one of the three oldest terrains on Earth, and by far the largest Eoarchean terrain in the world (~20 x 40km). Scientists have dated some of the rocks as old as 4.017 billion years (Collerson et al. 1991).

Rizo and her team combed through this region for these rocks to take back to the lab for closer examination. While in the field, they were accompanied by native Inuit bear guards, whose elders survived in the Canadian arctic and subarctic for centuries. 

Although most of the Inuit live in small urbanized communities today, some of them still maintain a traditional Inuit way of living like hunting for their own food and treating sealskins for clothes.

“We were discussing with one of the Inuit, Ned, during dinner time, and he was telling us stories about his life, his travels all alone on a ski doo during winter, his encounters with polar bears and hunting adventures,” said Rizo. “And he suddenly asked us in a very humble way, ‘What do you guys hunt?’ It was such a natural question to ask for him, but so surreal to me. I wanted to laugh, and at the same time I felt so ashamed that we would never be able to survive over there, if we were not accompanied by the inuits."

By examining these fragments of untouched terrain called home by Ned’s earliest Inuit ancestors, Rizo and her collaborators hope to find further hints about Earth’s evolution billions of years ago. 

Rizo's participation in the field portion of this project was supported by a grant from Carnegie Canada.

Written by Robin A. Dienel
28 August 2014