Tuesday, May 20, 2008

Lake Mountains

We live 20 minutes from Pelican Point, on the west side of Utah Lake, so it is an easy location for a quick trip. We've gotten to know the area fairly well, and it is an interesting geological location. There are extensive clay and calcite deposits, and an active mining presence (Dyno Nobel, the explosives company, has some kind of operation here--maybe for clay). The hills seem to be largely composed of slate, with large and frequent layers of calcite. At one point these layers were turned vertical, so now they can be seen running along the hillsides. If you drive around you might see long, straight pits dug into the hills, sometimes ending abruptly and continuing on further down. These are prospect pits for calcite--the deposits run in straight lines from north to south.

The calcite seems to come in either a layered, "onyx" form, or in large masses of crystals that vary in color from white, to yellow, to green. The long prospect pits usually contain the massive kind--they can be found coating the walls or laying on the ground in boulders, some larger than a dishwasher. The banded variety usually comes in brown or white and yellow, sometimes with green or red bands, and it can be found both in the pits or scattered on the hillsides, where they weather out of the ground.

A friend and I recently visited the area to see if we could find any additional collecting sites. I had previously visited one of the prospect pits, and had also found a small quarry for the banded calcite, but had no idea of the prevalence of good material in this area.

The most car-friendly area can be found by turning west off Westlake Road at the Dyno-Nobel sign and driving into Little Canyon. After a half mile you will drive right through the middle of a gravel quarry--you'll probably have to weave in and out of the heavy machinery parked there (we always visit on the weekend. It might be a little more difficult during the week.) We visited some prospect pits to the left. I jumped down in the trench and realized that the walls were composed of pure calcite. One whack with a hammer and the dirty, brown rock fell off to reveal beautiful, glassy calcite crystals. We started hammering on a large chunk of rock that had fallen to the ground, and it instantly crumbled into a pile of orange crystals. We looked around for awhile and finally found some rough that was possibly solid enough to cut, and jumped back in the car to explore some more. I realized that by cutting the rough crossways I could get that orange honeycomb calcite that I've seen in shops around Utah, although I doubt the stuff is as sturdy as the kind used in construction (check out this site for some beautiful uses of the material.)

We jumped back in the car and drove a little further. We noticed a hill with an outcropping of slate, so we got curious and poked around a little. After a few minutes we started to find shells--some were impressions in the slate, and others had pieces of shell in them. Many of them were blue and white, as if the shell hadn't been replaced at all. This site warrants another visit.

We kept driving, finding banded calcite in almost every cut in the hillsides. We also saw a few snakes. In one area, we saw some strange rock conglomerates crumbling out of the hillside that appeared quartz-bearing. One had a beautiful layer of blue chalcedony inside a cavity.

It's always fun to return to an area you've already visited. The first visit is often hit-or-miss, because you're trying to find the main collecting site. When you go back you usually have more time to survey the area, and that is when you often find new locations and better material.

1 comment:

Anonymous said...

I lived in a house that borders that area, which is BLM land and then Dyno Nobel property(which is an explosives plant that I worked at, not a mining facility.) I used to hike and explore that entire area and I've found walls of limestone with precambrian fossils that are beautifully intact, as well as a vein of banded, bright green calcite (the exact location of which only I know, for now) and have also found lava concretions, apache tears and lots of other great stuff. I've mentioned to alot of people that the Lake Mountain area is GREATLY overlooked for its rockhounding pleasures. Just watch for snakes and cougars!