THE CATSKILL GEOLOGISTS BY PROFESSORS ROBERT AND JOHANNA TITUS - How Many Years Can a Mountain Exist Before it is Washed to the Sea

CATSKILL - Do you recognize the words of our title? Yep, that’s from Bob Dylan’s 1963 song “Blowin’ in the Wind” And, double yep, the two of us are old enough to remember when the song came out. We have seen the recent movie, and that set us to thinking about it. Dylan must have taken a good earth science course somewhere along the line. It’s a poem set to music, and, in this line, it describes the slow weathering away of a mountain. But we are not poets nor musicians. We are geologists, so we immediately began thinking of the formation of the Catskills. Suddenly, we realized that we could answer one of Dylan’s poetic questions; we can actually estimate just how many years a mountain exists before it washes to the sea. That may seem like a goofy idea, but it does, as we so often do, take you into the minds of two scientists! It’s just the sort of thing we are always thinking about. Take a look at our illustration.

That’s a cross-section view of Catskill stratigraphy as envisioned by our friend, the late New York State Museum geologist, Dr. Don Fisher. Decades ago, Don set out to draw this image, and it has become a standard illustration used by numerous geologists. It portrays a lot of history. Those black strata, down at the bottom, especially to the left, show dark, thin-bedded seafloor shales. Those were silts and clays washing off of a still young but rising mountain range. These were the Acadian Mountains, and they were located in today’s western New England. Bob Dylan’s mountains had appeared and they were, indeed, washing into the sea. The overlying gray strata are more marine deposits: sandstones. And the reds mark the terrestrial strata, mostly sandstones of the Catskill Delta. That delta formed at the bottom of the Acadians. There is, indeed, a lot of history here. The Acadians were growing taller and taller. And then they were eroding away to produce the sediment that filled up an adjacent sea and then produced the Catskill Delta that Don Fisher portrayed.

Well, that tells us about the origins and then the erosion of those mountains but, what about the “how many years” part of the Dylan song? That got us to examine some more work that the State Museum has done. We looked at some more of their publications and found that this sequence of strata is thought to have been deposited between 393 and 372 million years ago. It took 21 million years and maybe a little more to “wash those mountains into the sea.” Do any of you have Bob Dylan’s mailing address? Perhaps you can clip this column and end it to him. We think that he should know all of this.

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.” Read their blogs at “thecatskillgeologist.com.”