Sometimes making sense of geology is like a game of Jenga. Just as soon as I decipher one concept or event, I have to pull out another, and another. Sometimes just everything begins to make sense a new concept will come into play that will topple my tower of acquired knowledge. December was all about figuring out how Onondaga Limestone got to its present geographic location. With the help of my mentor Ms. Utterback, I was able to make sense of some USGS pages and piece together the story of the deposits in the greater Albany area. Below is a diagram from a USGS page on the Hudson River Valley concerning this subject.
The vein that I'm concerned with right now is the one under the Catskill Group labeled Helderberg Group, Onondaga Ls. & Hamilton Group. These three groups were formed during the Middle Devonian period (see last post for more on this). In this diagram we can see four or five distinct times of movement which are visible as the black diagonal lines. In the first movement the Onondaga group was pushed from one side of the Hudson River to the other. How exactly did the rock get moved from one side of the river to the other? Stay tuned for the answer in January!
-Jess
-Jess