Geology 101

You can’t help but be impressed with the landscape when you first arrive on Cedar Mesa. The surrounding mountains, the colorful sandstone formations, the deep canyons cut by flash flooding intermittent streams, the miles and miles of junipers, sage, pinyon pines covering the land. 

Ergo, it seems appropriate to speak a little to how this all came about. Millions of years ago this area was a vast inland sea that alternated between being marine, beach and desert environments. Over a very long time (250 million years more or less) sand, shale and limestone sediments were deposited alternately with one another to form the varicolored landscape we see today. 

Here on Cedar Mesa, the dominate rock type is called - appropriately enough - Cedar Mesa Sandstone. It’s a thick deposit of wind-blown sands when the inland seas had temporarily retreated and a Sahara Desert-like environment predominated. It’s easy to see this when you look at the cross stratification in the rocks. 

Why the varied colors you might ask? Well, that had to do with shifting beach sands (buff) alternating with other materials (reddish) washed down from nearby mountains. Each have their own density and resistance to erosion – which is why we get the fantastic shapes we do today.

The bottom line is that eons of uplift, and wind and water erosion carved the canyons of Cedar Mesa. These are the canyons I wander now; the canyons that once were the home for many deer, bighorn sheep and Ancestral Puebloans. The canyons that supplied the rocks these first people built their houses with - and their kivas and storage structures. These canyons also provided rock walls on which they painted or pecked their art.

While it looks tough, this sandstone is actually quite porous. As water moves down through this rock it resurfaces as seeps and springs which dissolves the cement binding the sand grains of the rock together. Over thousands of years, water and wind removes these grains one by one, which allows the collapse of overlying material in the cliffs and forms alcoves. These are the alcoves that provided shelter for the ancient people who came to inhabit this area and are what make Grand Gulch special. 

And here endeth the lesson...