This article is over 5 years old and may contain outdated information.

Environment

Geography word of the week: Unconformity

Unconformity: An interruption between layers of rock, in which the upper layer is much younger (even by more than a billion years) than the lower layer.
  • Jan 19, 2016
  • 130 words
  • 1 minutes
Expand Image
Advertisement

Unconformity
[uhn-kuh n-fawr-mi-tee]

Definition
An interruption between layers of rock, in which the upper layer is much younger (even by more than a billion years) than the lower layer.

Origin
The first known use is believed to date to the 17th century. Its first geological use is from 1829.

Example
A bedrock map of North America (shown above) nicely illustrates one major unconformity (part of the world’s “Great Unconformity”) where the crystalline rocks of the Canadian Shield (red) are overlapped by the fossil-bearing rock formations of the North American plains (green). Not coincidentally, a number of Canada’s largest lakes — Great Bear, Great Slave, Lake Winnipeg and Georgian Bay — lie along this transition zone. Significant mineral deposits are also often found near unconformities.

Advertisement

Are you passionate about Canadian geography?

You can support Canadian Geographic in 3 ways:

Related Content

Climate strike Victoria BC

Environment

Why Canada should recognize its citizens’ environmental rights

David Boyd, a Canadian environmental lawyer and UN Special Rapporteur on Human Rights and the Environment, reveals how recognizing the human right to a healthy environment can spur positive action for the planet

  • 1444 words
  • 6 minutes

Kids

Meet the 2015 Canadian Geographic Challenge participants

  • 1691 words
  • 7 minutes

People & Culture

Kahkiihtwaam ee-pee-kiiweehtataahk: Bringing it back home again

The story of how a critically endangered Indigenous language can be saved

  • 6310 words
  • 26 minutes

Environment

How does your garden grow?

As cities and towns continue to expand into our wild landscapes, conservation gardens can provide refuge for Canada’s plummeting biodiversity

  • 3586 words
  • 15 minutes