Teachers' Domain; Earth and Space Science; The Grand Canyon: Evidence of Earth's Past

The Grand Canyon reveals the inside story of the ground that lies beneath our feet. Lying open a mile deep is the board of Earth's history a chasm whose rules of layered rock tell the tales of two years in the life of the planet. These layers of the rim which turn to rock just before the age of dinosaurs on the canyons youngest formations there are 21 distinct layers of rock you each one representing a package of about 13 billion years of time gone by as we cast our gaze down the canyon was we're looking at older and older rocks in the deepest part of the canyon. The rocks are 1.7 billion years old. A third as old as the Earth itself. Each rock. By the type of particles it contains tells the

story of its own origin. Sand becomes sandstone. Becomes. The skeletons of sea. Three shallow sea like this one are not on much of what is Western. In the red limestone is a marine deposit formed in a shallow sea. Millions of years ago and we know that because right here is one of those marine shells. I'm going to pour some water on it so that it shows better. This is the shell. Sort of cylindrical shell with her partitions across it.

And it's related to the modern chamber which currently lives in the Indian Ocean except these have straight shells in the chamber when it's hard to imagine all of the things that are going on in this place but the Grand Canyon record tells us mountain ranges seas that have advanced and retreated at least 18 times across Arizona. A variety of conditions desert dunes and all of these marvelous things have happened. In this place over a period of two billion years and they're recorded in the Grand Canyon right.