QIKIQTARJUAQ/BROUGHTON ISLAND
Rocks found on Baffin Island hold clues to the origins of water on Earth.
Padloping Island, southeast of Qikiqtarjuaq, was once a very small community of both Inuit and southerners, but now has been shown to hold clues to water's origin on the planet. - photo courtesy of Lydia Hallis |
To the southeast of Qikiqtarjuaq lies Padloping Island, once a traditional camp home to a few dozen people during the 20th century. It is about six miles long, but what makes it special today are the clues found in its lava flows.
"They originate from a source down in the deep mantle, possibly at the boundary with Earth's core," stated Dr. Lydia Hallis, Marie Curie Research Fellow at the University of Glasgow, in an e-mail to Nunavut News/North.
"Because they are sourced from so deep down, and because chemistry suggests the rocks' source has been untouched for over 4.5 billion years, almost the age of the Earth, we know they haven't been affected by geological processes at the surface. Therefore, these rocks contain small amounts of Earth's earliest water."
She led a team of researchers trying to find out where in the solar system Earth got its water.
From studying the rocks of Padloping Island, she found that Earth's first water had a different hydrogen composition to the water at the surface today, such as in rivers, oceans and the atmosphere.
"This different composition indicates that this initial water was sourced directly from the disk of gas and dust that surrounded the sun during the early solar system," stated Hallis. "In other words, Earth has had most of its water all along - it wasn't added later by comets and asteroids."
She called Baffin Island's geology extremely interesting. It, along with Greenland, contains some of the oldest rocks on the planet. The samples from Padloping, though, were relatively young in geological terms, only about 60,000 years in age.
But those young rocks came from an ancient deep-mantle source, which is older than any surface rocks on the planet and dates back to the time the moon was forming.
"The rocks of Padloping Island are a window into early Earth's chemistry," stated Hallis.
She and her team studied the rocks through an ion-microprobe instrument to measure their water content.
The Padloping rock samples were collected in the mid 1980s by Dr. Don Francis of McGill University.
They have been studied intensively since then, and Hallis's work is based on years of previous research.
"I really hope to be able to come out to Baffin Island and collect some more samples," she stated. "The special nature of these rocks means they deserve more study, but there isn't that much material left from the original expedition. A new sample set would prompt more research from the wider geological and planetary science communities."
