ONCE AGAIN, we are working with the Columbia County Land Conservancy. One of us, Robert, will be leading a geology walk at the High Falls Preserve in Philmont on Saturday, October 22 at 10 a.m.
High Falls is a pretty waterfall with a surprisingly complex geology. Our group will walk up the canyon there and learn about its geological history. The rock unit here has been mapped as the Elizaville Formation. We read about it in a book by our friend, the late Dr. Don Fisher. Maybe you knew Don; he ran the rock shop in Kinderhook.
The Elizaville Formation is mostly a black shale, and we can deduce a lot from that. Before it hardened into shale this was a sediment of black clay and silt. That is something that usually accumulates at the bottom of a very deep ocean or even an abyss. It’s stagnant down there so there is no way that atmospheric oxygen can get into those waters. With no oxygen, there are relatively few bacteria. That means that biologic material does not decay, and the shale is black, the color of fine particles of biologic material.
What a remarkable thing this is; we are looking at Philmont when it was at the bottom of that ocean, called the Iapetus Sea. Don estimated that this was a bit more than 543 million years ago, a time called the Proterozoic.
It is likely that it really was a very deep sea and there is a reason for that. Our part of the world was, quite literally, breaking up. Plate tectonics created enormously large geological faults which were splitting the region’s crust into uplifted and downwarped blocks. Our part was downwarped, so much so that we had that deep ocean, quite likely many thousands of feet in depth! If you join us on October 22 or if you go on your own, look around and think about all this.
Contact the authors at randjtitusprodigy.net. Join their Facebook page “The Catskill Geologist.” Read the blogs at “thecatskillgeologist.com.”
