A craton is a large, stable portion of Earth's lithosphere that makes up part of a continent. The Kaapvaal craton in Africa is o
ne of five ancient cratons left from the Precambrian era. The rock has remained tectonically stable since its formation 3.6 billion to 2 billion years ago. What do you think the term "tectonically stable" means? Why do you think this rock formation is important to understanding the history of Earth? Do you think studying ancient rock formations such as the Kaapvaal craton can teach scientists not only about Earth's past but also its future? Why or why not?
Tectonically stable means that this part of the continent has not moved for billions of years. The rock formation is important understanding the history of Earth since its unmoved and untouched state can provide ideas about how the Earth looked like as seen on the layers of the rock formation.
Dune deflation hollows are where wind has removed sand down to a level where a layer of particles too heavy for the wind to move (an armoured surface) stabilises the sand and prevents the surface being lowered further.
A crevasse is a deep, wedge-shaped opening in a moving mass of ice called a glacier. Crevasses usually form in the top 50 meters (160 feet) of a glacier, where the ice is brittle.
a mass of rocks and sediment carried down and deposited by a glacier, typically as ridges at its edges or extremity.
The data collected by the census determine the number of seats each state has in the U.S. House of Representatives (a process called apportionment) and is also used to distribute billions in federal funds to local communities.