Rock Talk – what do we mean by Rock Talk. Well read on – it is a lesson in geology!
Know The Canyon’s History Study Rocks Made By Time. Got it?! This is how Grand Canyon Whitewater river guides first began their geology lessons of the Grand Canyon. Confusing? Let me explain…this sentence is a mnemonic (said “ni-MON-ik). The first letter of each word represents the first letter of each of Grand Canyon’s Paleozoic rock layers in order from youngest to oldest.
Know is for Kaibab Formation. The Kaibab is a mix of mostly limestones, sandstones and siltstones and is the first layer you come in contact with on your Grand Canyon rafting tour.
The is for Toroweap Formation. This is also a mix of limestones, sandstones and siltstones.
Canyon’s is for Coconino Sandstone. This layer is really cool; you can see cross-bedding created from old sand dunes.
History is for Hermit Formation or Shale. The Hermit Shale is deemed the “Painter of Grand Canyon,” the deep rust-red color of the rock actually leaches out and stains the layers of rock that sit below it.
Study is for Supai Group. The Supai Group is my favorite, composed of 4 BEAUTIFUL layers of rock mainly sandstones and limestones. The Supai Group is what makes the upper part of a Grand Canyon raft trip and Marble Canyon so spectacular in my opinion!
Rocks is for Redwall Limestone. This layer is the essence of Grand Canyon. It usually forms a sheer cliff from 400-700 feet in height! Although this layer looks deep rust-red, remember that is only a stain from the Hermit Shale, underneath the stain this layer is actually grayish-brownish. This is a really neat layer encountered on your Colorado raft trip.
Made is for Muav Limestone. The Muav is sometimes hard to identify, but usually is gray in color.
By is for Bright Angel Shale. The Bright Angel is a gorgeous banded layer of greens, purples, tans, and deep browns. It is very soft and its erosion helps widen Grand Canyon.
Time is for Tapeats Sandstone. It’s hard to believe that this rock layer so deep now in Grand Canyon was laid down near a shore; think beach.
So there ya have it, Grand Canyon Whitewater’s Geology lesson in a nutshell…or a mnemonic. Come back for more rock talk! Better yet call Grand Canyon Whitewater and book you Grand Canyon
geology tour today! 1-800-343-3121.