Taxonomy term

lionel e. jackson jr.

Diamonds and the Eocene climate of the Bell River Basin

Diamonds mined from the kimberlite pipes of the Lac de Gras diamond field in Northwest Territories, Canada, are among the world’s youngest known diamonds, dating from 75 million to 45 million years ago. In some cases, when the magmas that carried these diamonds to Earth’s surface encountered water-saturated rock at shallow depths, violent steam explosions called phreatomagmatic eruptions resulted. Such explosions can form volcanic craters known as maars, which often fill with water and accumulate lake sediment, along with soil and vegetation that collapse into them from their margins. In the case of the Panda kimberlite pipe at the Ekati Mine in the Lac de Gras area, maar sediments accumulated far below the surrounding terrain, such that they were later buried under glacial deposits rather than being eroded away by ice sheets during the past million years. Wood and other organic materials were entombed and preserved in their natural state, thereby preserving shreds of the Paleo-Bell River Basin.

25 Jul 2018

Saglek Basin sediments suggest a Grand Canyon connection

Pollen makes an ideal fossil. Pollen grains — each only a few tens of microns in diameter — are produced in astronomical quantities by plants and record information about the ecosystem from which they came, thus providing a way to reconstruct past environments. Additionally, pollen is composed of a highly stable organic substance, sporopollenin, which resists decay as well as the high heat and pressure associated with deep burial, lithification and tectonism. It is so resistant, in fact, that it can be eroded from rock and recycled into younger sediments, a process recognized in the 1980s by V. Eileen Williams of the University of British Columbia in her studies of Paleo-Bell River sediments deposited in the Labrador Sea.

25 Jul 2018

The Paleo-Bell River: North America's vanished Amazon

With similar geologic and tectonic histories, including a continuous mountain cordillera along their western margins, why does South America have a massive river draining a continentwide basin but North America does not? Before the Pleistocene, it did.
25 Jul 2018

Urban geology: An emerging discipline in an increasingly urbanized world

Urban geology — the geology just outside, or perhaps under, our front doors — should be recognized as its own specialty. After all, its applications impact more than half of the global population.

21 Feb 2016

Urban type sections

It might surprise people to learn that some type sections can be found in cities. Type sites require conservation and protection

21 Feb 2016

Siwash Rock as an urban geoheritage icon

Siwash Rock in Stanley Park, Vancouver, British Columbia, is a prominent and photogenic sea stack — an erosional remnant of an Oligocene basalt dike that cuts through Cretaceous sandstones. The rock (properly named “Slahkayulsh,” meaning “he is standing up”) is a geoheritage locality in both aboriginal and nonaboriginal iconography. 
 
21 Feb 2016