I just got back from a trip to Enchanted Rock and I wanted to write up a trip report. Enchanted Rock is without question one of the best hiking spots close to Austin. It's located about 90 minutes west of Austin between Fredericksburg, TX and Llano, TX. That's actually quite convenient because there's great food in both: German in Fredericksburg and BBQ in Llano. This trip to Enchanted Rock was quite special because it was completely covered in wildflowers. Here's an example of what I mean:
We've gotten a lot of rain lately and that seems to have done wonders for the wildflowers. I have never seen Enchanted Rock like this in more than 20 years, so if you've been waiting for an opportunity to go out there I HIGHLY recommend going now.
Enchanted Rock is also very interesting from a geologic perspective. Enchanted Rock is part of an extensive batholith, an intrusion of igneous rock, which is one of the largest such structures in the state and the country. It is composed of Precambrian rock and is one of the oldest pieces of exposed material in the United States. Intrusions such as Enchanted Rock form deep in the earth’s crust when magma intrudes into a pocket and cools slowly to form igneous rocks such as Granite. You can tell by the grain of the rock that the intrusion cooled first at the center and continued cooling outward from there.
One of the lesser known facts about Enchanted Rock is that it's not just part of a batholith, but is also an exfoliation dome. Exfoliation occurs through weathering: water seeps into pores in the rock and freezes which causes it to contract and crack the rock Concentric shells of the exposed surface crack like a shell, and slabs of rock are removed from the outer surface in layers. You can see the layers everywhere, some of the pieces are left behind on the surface of the dome and others have slid down to the land below. Here's some pictures of what some of these slabs look like, as well as an exfoliation layer just beginning to peal away.
If you've ever looking for a great place to hike, camp, or picnic then I highly recommend Enchanted Rock. In addition to the great scenery and neat rocks there's also a network of caves and several good rock climbing routes (not to mention bouldering). It's a great place to go. And don't forget to stop in Fredericksburg for a beer afterwards.
See more photos at my 500px.