Holcim Quarry Trip
The first stop was an area where they had removed about 30 feet of the over burden and created a large bench. Joe told us the look around the base of the wall. I started walking along the base and found some chunks of calcite but nothing worth taking home. I headed towards a small group on the north side of the bench. As I got closer I started finding bigger and nicer pieces of calcite. Calcite boulders were scattered at the base of the wall. I picked up a nice piece that weighted about 30 pounds. It has nice blades on one side. Bob Leoffer was working a spot about 10 feet above the bench. As I got closer I saw what he was working on. It was a vein about 10 feet high with an opening in the shale about 1 foot wide. The calcite had grown in from both sides but had not joined. This allowed very nice blades to form on both sides of the fissure. Bob removed several nice plates for himself and I went up to help. About the time I started removing the calcite plates Joe yelled that we had 10 minutes before we had to go to the next area. We went into high gear and removed as much as we could and gave it to others that were not able to come up and dig. Several feet to the left there was another surface covered with smaller blades of calcite. I was only able to get a small piece from this area also.
The large calcite blades were covered with a red and black stain. I used Super Iron Out and the stains came off.
Joe took us to an area with piles of over burden. The over burden consisted mainly of shale. The zone that is being mined is approximately 100 down so there is a lot of overburden that must be removed before the limestone can be mined. The limestone layer is about 43 feet thick. The pyrite forms within the shale. It needs something solid to start forming on. The pyrite attaches to grains of sand, gravel, shells and even twigs. The pyrite formed prior to the shale becoming hard.
At first I was not sure where to start looking. As I started climbing over the piles of shale I started seeing the pyrite balls in the shale. The shale ranged from gravel size to boulders weighing thousands of pounds. The shale split easily, but if there was a pyrite ball it split along the same plane. So splitting the shale wasn't the way to go. As I climbed over more shale I started seeing clam shell fossils. I found one that was partially replaced by pyrite. I think the best method to find the pyrite balls is to rake through the gravel size shale pieces until you see something shinny. The pyrite balls I found ranged from ¼" to about 1".
After about an hour Bob came over with a big grin on his face. He had found the back 1/3 of a fish fossil. This wasn't one of those little 2" long guys, this fish must have been 18" long when it was alive. The tail was about 3-4" wide and was attached to several vertebra. Awesome, awesome, awesome is all I can say.
This is part of an email Bob sent me: "I've been told that fish fossils at the Holcim quarry are pretty rare, so a guy named Jerry Sucher is going to look at my fish tail fossil in the next couple weeks. Bob Landgraf (one of the guys on the trip and a member of the CSMS and our club) contacted Jerry. I sent him a couple pictures of it and now he is excited to see it. Sweet. :-) It won't be worth anything since I found just the tail, but it could be important from a research perspective."
Bob also found a nice sharks tooth in the shale.
All in all it was a great trip. For those that didn't get a chance to go my advice to you is to bring a napkin with you to the towel show because those of us that went don't want you drooling on our finds.