LIVING ON THE EARTH

LIVING ON THE EARTH

"ROCK OF AGES" THE CRESTONE CONGLOMERATE

"ROCK OF AGES" THE CRESTONE CONGLOMERATE

Long, long ago, and very, very close by, there rose up a mighty mountain range, the Ancestral Rockies. They overlooked a vast inland sea fed by glaciers.

All are long gone. But ample evidence of the Ancestral Rockies dots today's local landscape. They're those fascinating rocks that are colorful collections of all different rocks rolled up into one, and range in size from hand-held to big as a house.

Many locals tell visiting friends and family that they are unique. They may not be one-of-a-kind in the world, but they are rare and the formation they come from is very rare.

Crestone Conglomerate rocks are a mix of quartzite, pink granite, sandstone, schists, and gneisses cemented together in a matrix of the-grained silica. What's the process? Look at the San Luis Valley: it's a big basin with thousands of feet of sand and gravel.

The pressure of the sand at the bottom is intense, and the ground - is slowly flowing through the bottom gravels. The groundwater has dissolved chemicals in it, which are present in solution, and they precipitate in the pore spases of the gravel, and cement any rock that's at the bottom of a pile.

Although the Crestone Conglomerate was formed 300 million years ago, it contains much older rocks. When you look at the Crestone Conglomerate, you're actually looking back several rock cycles.

And, as locals have learned, although these "rocks of ages" aren't so great to build with, they definitely make interesting conversation pieces, and decorative and unusual landscape additions. Some of them are quite beautiful in their colors and works of "rock art" in their own right...