Horseshoe Bend Geology



 

 

Before you have the chance to see the iconic view of Horseshoe Bend just South of Page, Arizona, your first challenge is to make your way up a mildly steep hill through sand. Though most visitors succumb to the temptation to make quick work out of this small incline, you might view it as an opportunity to take a trip through time by observing the unique geology.

About 200 million years ago, a massive sea of sand dunes, similar to the Sahara Desert, covered the landscape from Arizona to Wyoming. The sand slowly solidified into a layer of Navajo Sandstone over 2,000 ft thick in some areas. After the bedrock of Navajo Sandstone formed, other sedimentary layers of sandstone, mudstone, calcite and limestone settled on top of it. Over millions of years, the canyon began to take shape by the constant erosion of relentless winds, flash floods, and extreme heat and cold. Today, the Navajo sandstone is once again exposed, and its top layer is turning to sand. The hill is what remains of a gigantic sand dune that actually saw dinosaurs walk upon it. Indeed, there is a small, but hard-to-find dinosaur track about 50 yards from the end of the trail. Tell us the GPS coordinates if you happen to find it!

NobuTamura email:nobu.tamura@yahoo.com www.palaeocritti.com - Own work

As you crest the hill the geology changes. Tan gravel and chunks of sand also make an appearance. These are remnants of the calcite, or limestone layer that was once here. The diagonal stripes in the rock formations tell the story of how the sand dunes retained their former shapes over the course of 20 million years.

As you get closer to Horseshoe Bend Overlook, you’ll notice that some of the rock formations have dark, sandy nodules. These are known as “iron concretions.” Iron is heavier than sandstone, and iron tends to cluster up into small spheres during the process of petrification. As the sandstone erodes away, these dark sand spheres are becoming exposed to the elements once again. Occasionally, they will break away from the sandstone bedrock. When they do, they become what are known as “Moki Marbles.” If you find one – or more – please don’t pocket them. Remember, take only pictures and leave only footprints!

Once you get past 20 millions years of geologic history you get the see the majestic results of erosion, Horseshoe Bend! Horseshoe Bend was formed by water following its natural path of least resistance. The sheer Cliff walls are made of Navajo Sandstone, a particularly dense type of sandstone. In the process of erosion, the sandstone acted as a natural barrier, forcing the water to make a sharp bend in the river thorough softer rocks.

The Colorado River is about 1000 ft below you, the blue green color is always 40 degrees because it flows from the bottom on the Glen Canyon Dam. Take this opportunity to take some once in a lifetime pictures. Our guides will be more than happy to show you the perfect spot for your photo shoot!

 

References/Photos:

Images

Creative CommonsAttribution 3.0 Unported

 

Dinosaurs

NobuTamura email:nobu.tamura@yahoo.com www.palaeocritti.com - Own work


Share it


Comments (0)



Add a Comment





Allowed tags: <b><i><br>Add a new comment: