Wednesday, October 12, 2011

Breccia Struggles

Blue Jay Barrens has many examples of hostile environments, but the most life unfriendly has got to be the breccia hills. These steep slopes surfaced with rock chips are an almost impossible place for plants to grow. The struggle of plants trying to colonize this rugged area is fascinating.

The breccia is a product of the meteor strike that occurred around 300 million years ago. The strike fractured the limestone and created a mass of rock chips. These chips were then cemented together. Exposure to weather causes the cement to fail and a layer of loose chips is created.

The lack of a soil covering is a product of poor land use practices. During the time of active farming, this area was plowed and the process of erosion was begun. The extent of the erosion was absolute. All of the soil that had been building over thousands of years was lost in just a few decades. If the objective had been to strip the soil from the land, this would be a grand prize winning site.

Beneath the breccia is a more solid layer of limestone. This base gives form to the breccias hills. As the chips break loose, they migrate down the hill. The underlying rock is now exposed in several areas.

The chips don’t go very far. Most are trapped at the base of the hill. Some make it down to the creek where they contribute to the section of gravel bottomed stream.

Some areas still have a bit of subsoil over the breccias. The poor soil is not conducive to rapid plant growth and still shows signs of erosion. Things actually look worse than they are. As the soil eroded, rock chips became exposed on the soil surface. These chips worked to protect the soil from additional erosion. The result is a combination of pebble covered shelves flanked by stone topped columns.

Grass is slowly taking hold on the breccias slopes. It’s a slow process. A severe drought causes many of the young pioneers to die. Excessive rainfall causes enough chip movement to disrupt the growth of small plants. It took many years for these grass plants to become established. They seem to be in good shape now, but their position is far from secure.

1 comment:

  1. I've always loved seeing rugged plants growing in what seem to be rather inhospitable conditions. Glad to see I'm not alone.