Not every thing is bigger in Texas

Pluton, monadnock or exfoliation dome, no matter what it is called, Enchanted Rock, a pluton and one of three geo-sites in Texas,  exposes the oldest rocks found in the state. It is also fun to climb (see May 3, 2014 blog post) and Mr. Spock never tires of talking about how ancient, more than 1 billion years ago, deep-seated forces metamorphosed some subsurface rock into massive chambers of liquid rock that percolated upward and crystallized into granite that was subsequently covered by multimile-thick sediment that formed limestone over the granite.

Erosion over the past 12 million years has brought the granite to the surface, exposing the pluton. Without the confining pressure of overlying rock, granite plutons, such as Enchanted Rock, expand in volume and split into curved sheets that slowly fracture and weather away, creating the rounded profile of Enchanted Rock. 

The Summit Trail climbs 425 feet in 0.6 miles. In contrast, Stone Mountain in Georgia, is 825 feet above the surrounding landscape. Stone Mountain is 7 miles in circumference, Enchanted Rock is 2 miles. However, Enchanted Rock is the largest pink granite dome in the U.S.

Mr. Spock and Frederick finding a kind of oasis on the top of Enchanted Rock with cactus and succulents.

The guys exploring the vernal pools on the top. Notice the lowering clouds that got us thinking that we didn't want to be on the summit if there was the possibility of lightning. 

Frederick helping Mr. Spock hike back down from the summit.

Following the hike to the top, and after eating our lunch, we decided on taking the Loop Trail around the base of the various plutons; Enchanted Rock being the largest of 4 or 5 more. Here's Enchanted Rock from the southeast.

The Loop Trail was one of the most pleasant trails we have traveled. Along a portion of the trail was this babbling brook...

which had to be crossed at one point.

Exfoliated slabs of granite peel away from the surface of Enchanted Rock, similar to the way an onion separates layer by layer, hence the rounded shape. Enchanted Rock from the north.

At one point on the 4 mile Loop Trail we took a spur to a scenic overlook and were rewarded with a rainbow. Perhaps you can see it just above center right.