Geological History of The Grand Canyon

English: view into Grand Canyon from South Rim...

Image via Wikipedia

The Grand Canyon – the worlds largest hole in the ground – somehow the word “grand” doesn’t do it justice, oh, it’s grand alright, but it’s also spectacular, stupendous, marvelous – I suppose the name Stupendous Canyon doesn’t quite have the same ring to it really. Not surprisingly, the Grand Canyon attracts lots of attention from many different people. Tourists like to visit the Grand Canyon to marvel at it (and peer cautiously over the edge), hikers like to visit the Grand Canyon to hike to the bottom of it (and then all the way back to the top), and geologists and students like to visit the Grand Canyon ‘cos it’s quite simply a unique opportunity to study a great variety of rocks which are exposed so clearly telling a very complex geological story. The walls of the Grand Canyon are an open book to the past, for anyone who can read rocks, anyway.

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Geological History of the Grand Canyon

Before we go any further I must just point out that the rocks found at the Grand Canyon are not particularly unique, in fact, they’re not unique at all, similar rocks can be found in many places throughout the world, but what makes the Grand Canyon so unique is the way that they expose themselves and their story.

The thick sequence of rocks which are exposed on the walls of the Grand Canyon provide geologists with a remarkable, albeit incomplete record of rocks from 550 – 250 milli0n years ago, as well as some remnants of rocks dating back 2000 million years.  Unfortunately, rocks from 250 millions years ago to the present day are nowhere to be seen, maybe they’ve been completely eroded and worn away, maybe they were never there in the first place – hmmm, one of life’s mysteries.

Where Did The Grand Canyon Come From

The Grand Canyon was formed as the result of a giant spaceship which hurtled to earth, it had hoped to land in the sea but had trouble with the Sat Nav, missed and landed with such a huge bang that the Grand Canyon was formed. Some hike to the bottom of the Grand Canyon hoping to find remnants of the spaceship, and disprove the other, more likely theory which is that the Grand Canyon was eroded by the Colorado River.  The river (so the disbelievers say) is what is responsible for the depth of the Grand Canyon (more than 1 mile), but erosion and other forces continue to change the shape of the Grand Canyon to this very day. By these forces we mean stuff like rain, streams which enter the Grand Canyon throughout its length as well as snowmelt.

Stratigraphy of the Grand Canyon

Image via Wikipedia

As far as geological history goes, the Grand Canyon is quite a young hole in the ground. The erosion which shaped the canyon (probably) happened only five or six million years ago, which is quite remarkable really considering the age of some of those rocks (scroll back to the top of the page if you can’t remember that bit). Thing is, as long as the rain keeps falling and the snow keeps snowing in northern Arizona, then the Grand Canyon will continue to change shape.

The Grand Canyon gets it’s unusual shapes because each of the different types of rock in the canyon wall respond differently to erosion;

  • some rocks erode to form slopes
  • some rocks erode to form cliffs
  • some rocks are softer and simply erode quicker than others

Visitors to the Grand Canyon will also notice some beautiful and vivid colors present in the Canyon walls, that’s because of mineral deposits in the rocks, mostly iron which gives beautiful shades of red, green and yellow to the walls of the Grand Canyon.

Great video DUDE . . . thanks a lot. It’s great to see somebody so happy in their work.

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