Sunday, December 15, 2013

Rock Wall Stones

Weather: Sun now comes in my window and blinds me around 7:45 in the morning; what snow fell disappeared before the morning temperatures fell; last snow 12/09/2013; 8:31 hours of daylight today.

What’s still green: Juniper and other evergreens, prickly pear; leaves on Apache plume, German iris, yuccas, garlic, hollyhocks, winecup mallow, Saint John’s wort, vinca, coral bells, cheat grass; rose stems green.

What’s red: Cholla, Oregon holly and coral beardtongue leaves.

What’s grey or blue: Four-winged saltbush, snow-in-summer, pinks, golden hairy aster leaves.

What’s yellow or brown: Arborvitae.

What’s blooming inside: Zonal geraniums, aptenia.

Animal sightings: Small birds wintering in the area.

Weekly update: One of the more interesting things about rock walls are the stones themselves.

Anthropologists often try to identify the sources for the flint and obsidian used in arrowheads and other tools. When it is some distance from where the points were found, they posit some kind of division of labor between tribal groups and trade.

The important trait of rocks is they are heavy. Until motorized transport, only a very wealthy man in the Española area could have had them moved any distance by ox cart or horse drawn wagon.

Most of the material used in walls is volcanic, which can be found just north of town. River rocks also are used, but are less common.

When I’m driving by, I use a simple characteristic to determine which is which. If the surface looks porous or rough, it’s probably volcanic.

Most are lava, but one wall looks like tuff, rock consolidated from volcanic ash.

If it looks smooth, I assume it’s igneous.

When the stones are something else, they imply some unique history. When the man who lived next to the tuff wall wanted his own, he tried to find the same, but all he matched was the color. The darker rock on the right is denser than the tuff. The mason used different techniques for laying the stones and topping the wall.

Another built his wall from a deep reddish-brown stone. The wall was there when I moved here in the early 1990's. I would guess they were brought when road work was being done somewhere in the north. How the person got access to them is another story.

More recently, decorative rocks have become a style promoted by the mass media. Someone has even opened an outlet here for architectural stone.

Some rocks are beginning to appear in walls, that probably have been brought from afar. Sometimes, these are so narrow and uniform, they had to have been sliced by a rock saw.

The rocks used to line arroyo walls are less interesting when you drive by, but also aren’t natives. The Corps of Engineers probably specifies igneous rather than volcanic rock, since it would absorb less water. They could come from the Sangre, or be trucked in from elsewhere.

Photographs: Photographs taken in the area in the past several years. One below is a close-up of one of the rocks in the above picture.

No comments: