Blue Jay Barrens was pulverized by a meteor impact. Actually the impact took place before I named the area Blue Jay Barrens. About 300 million years before. The meteor drove everything before it deep into the earth, then gave way as all that battered rock rebounded to fill the temporary void. The result was an area about three miles across with rock of vastly different ages being close neighbors, rock layers tilting at all angles, radiating fault lines, and rock deformed by heat and compression.
One result was breccia, a sedimentary rock composed of cemented rock fragments. The breccia at Blue Jay Barrens is primarily limestone with a cementing agent of sphalerite, an ore of zinc that is often mined when found in sufficient quantity. Poor land management in the early 1900’s caused severe soil erosion to occur on large areas of Blue Jay Barrens. On the site pictured, the soil was completely lost and a large area of breccia was exposed. The sphalerite proved to be a poor cementing agent and breccia exposed to the elements quickly lost its cohesion and returned to its fragmented condition.
What we see today is almost inhospitable to plants. An Ash seed gives scale to this photograph. Freezing and thawing quickly change the breccia into fragments small enough to easily move with runoff water. This erosion usually occurs too rapidly to allow permanent colonization by plants.
Here you see an Eastern Red Cedar holding a small bit of soil on the breccia slope. Some of the cedars like the one here have been determined to be over 60 years old, but they still are less than six feet high.
Some Green Milkweed and Indiangrass have managed to become established on the lower part of this slope.
This Tulip Poplar seedling is off to a good start, but there is no way it can survive in this location. I doubt that it would have even gotten a start if it weren’t in the middle of a deer track. I think the deer compacted the soil enough for the seed to germinate and allowed for a protected environment in the slightly depressed area of the track.
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.
