"I will never kick a rock"

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Robert Titus has 322 articles published.

Cold enough for you? Jan. 13, 2022

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Cold Enough for you?

The Register Star

Updated by Robert and Johanna Titus

Jan 13, 2022

 

Our Catskill region summers generally bring wonderful weather with dry air and cool nights. Our Catskills Autumns are spectacular with their foliage. Our winters are dreadful and once again it is that time of the year. We stoically accept the onset of another cold season and make do with the holidays as some sort of compensation. Few of us, however, know or even wonder why we must endure this annual season. Do you? Many of you might be able to give a reasonably good explanation for our winter season in terms of the Earth’s orbit about the Sun. Many, or even most, of you, however, might flub the story; it is just a little too complex for a quick, glib explanation.

But it really doesn’t matter; we are not interested in the standard astronomical explanation of winter. We would like to consider a deeper reason, in fact, the real reason it is cold out there right now, and that has little to do with the Earth’s orbit and it has a lot to do with the Catskills and their geological history. If that surprises you then read on:

Even if your astronomy is not very good, most of you can probably run through a quick description of the Greenhouse Effect, it’s one of the leading environmental fears we face today. Briefly, our world’s industries are burning fossil fuels and pumping out large quantities of carbon dioxide into the atmosphere. Carbon dioxide traps solar energy much the way the glass traps solar energy in a greenhouse. As industrial production of carbon dioxide continues, it may be that the Earth’s climate will warm up with all sorts of unfortunate side effects. Such a fate is sometimes referred to as the “Greenhouse Earth.”

But what if it were the other way around? What if the quantities of carbon dioxide were declining instead of increasing? That gets us to a term which is rarely used – the “icehouse Earth.” That’s certainly not anything that anyone has been much worried about, but it actually has happened, and that gets us back to the Catskills.

The Catskill Mountains are composed of sedimentary rocks that date back to the Devonian time period. This was a time when the world was truly a Greenhouse Earth. There was 16 times as much carbon dioxide in the atmosphere then as is today. That greenhouse effect must have been enormous. But it was not to last. Off to the east, in what is today’s New England, there was a rising mountain range – the Acadian Mountains. As their uplift continued, they reached elevations that may have rivaled those of the Himalayas. Rising mountains are subject to chemical weathering and erosion. Those processes converted Acadian mountains into sediment which, eventually, hardened into the rocks of the Catskills. What is critical here is that the processes of chemical weathering consume carbon dioxide, they take it right out of the atmosphere. As the Acadians weathered away and the sediments of the Catskill accumulated, the amounts of carbon dioxide in the atmosphere dropped dramatically, from 16 times as much as today to something closer to modern levels. This, as you might guess, resulted in a reversal of the greenhouse effect and quite a cooling of the climate. In fact, there was an early ice age at the end of the Devonian Period???

There is plenty we don’t understand about this story, but this was a turning point in Earth history. Carbon dioxide would never again be as abundant as it was during the early Devonian. It levels would rebound again during the age of the dinosaurs and those great naked monsters certainly must have enjoyed the temporary restoration of the greenhouse heat. But there simply would never again be so much carbon dioxide and the climate would slowly deteriorate, with cooling temperatures, especially during the last 60 million years. Some argue that this is what caused the extinction of the dinosaurs. There is a good argument to be made too. Winters, which probably had not been much of a problem during the early Devonian, slowly become colder and more distinct from the rest of the year. The process has continued right into our time. In reality, even if industrial pollution continues unabated, ours is still a time of an icehouse Earth. Glaciers in Antarctica and Greenland attest to that.

So, are the Catskills responsible for winter? Well, that’s a bit of a stretch, but it is fair to say that the many processes that came to produce the Catskills were all part of a climate machine that eventually created the icehouse Earth climate that we can look forward to for the next two months.

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

The depths of Lake Bearsville; Jan. 6, 2022

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The depths of a lake

On The Rocks; The Woodstock Times. 2008

Updated by Robert and Johanna Titus

 

We geologists make observations and then we make deductions: that’s how our science works. In this light we would like to pick up where we left off the last time. In that last column we claimed that once, maybe about 14,000 years ago, all of Woodstock, extending west to Bearsville, lay at the bottom of a 280-foot-deep ice age lake. It is, logically enough, called Lake Bearsville. It has been recognized by geologists since the middle 1980’s but little research has been done on it. In the great scheme of things, Lake Bearsville is not all that important; it is one of many small lakes that formed at the end of the Ice Age. There are but limited numbers of geologists running around loose in the Hudson Valley and many other geological features are of more compelling significance. But naturally if you live in Woodstock this one is important. So, we have nominated ourselves to do the research and bring to the fore long lost images of the ancient lake. We think people around here should know something of their ice age heritage and this is as good as it gets.

Once we had determined that there had been a lake here and saw the lake bottom in the Bearsville area, we started looking for more evidence. We recognized that the lake had been formed by an icy dam. A glacier to the east, a tongue of the Hudson Valley Glacier, had blocked the flow of water in that direction. The waters of Lake Bearsville had to have escaped through some exit and it should be possible to find that egress. This kind of research is first done on a topographic map. You look at the contours and search out an old escape route for the waters. Our eyes were drawn to the top of County 46. There we saw a notch which seemed just right.

We drove up to this site and saw just exactly what we had expected to see. The notch lies near the very top of Little Beaver Kill. This is a stream which today, drains water off to the west. The notch at the top of the valley is what we geologists call a “paleoform.” It’s a landscape feature that formed in the distant past when things were different. Most streams do not have notches at their tops; they simply peter out. This notch actually used to lead into the Little Beaver Kill. Water rushed through it and on down the kill. Today, the notch is almost entirely dry; you will not see a stream flowing by at all. It looks like a stretch of valley though; we found small cliffs of bedrock which had been carved by the one-time flow of water that passed by here. That’s typical of a paleoform.

This notch is what we call a glacial spillway; it was once actively draining water out of Lake Bearsville. If you visit this site, turn to the east and, in your mind’s eye, gaze off in that direction and see the ice age lake that was once here. All along the shores you are likely to see platforms of ice extending out into the lake. The middle of the lake should be ice free, dark, and very deep. A slow current will be flowing toward you. As it approaches the notch, it is squeezed into the narrows between those two rock cliffs and picks up speed. A quiet but very powerful flow of water rushes past. There is something akin to the hum of electricity, but otherwise it really is silent.

Off to the west, the flow quickly becomes a loud chaos. A raging, foaming cascade makes up this ice age version of the kill as it pounds its way downhill. There is an enormous amount of power to all this; it is the very image of the end of the Ice Age. Glaciers are melting rapidly, hereabouts, and vast amounts of water have to drain off somewhere and they too must do it quickly.

There is nothing unique about this; all throughout the Catskills and Hudson Valley scores of similar ice age streams are, at this very moment, powerful cascades. To be on a hot air balloon, drifting across this landscape, on this day, we would see and hear all of them; it would have been unforgettable.

But none of us was on that balloon, and this image has been forgotten, until today, right here, in this column. It is the job of a geologist to resurrect the past, one chapter at a time and we have done this, our job, for today, except for one thing: we promised to explain how I knew that Lake Woodstock was 280 feet deep. Remember that the floor of the old lake lies, in Bearsville, at and elevation of 600 feet. The spillway lies at 880. You can do the math. Again, as I said the last time, when you travel west on Tinker Street, gaze up those 280 feet and see the icy lake that was once here. Geology has always been a science of discovery and this, we think, is a very good one.

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

 

Woodstock in the Ice Age Pt 5 – Lake Woodstock

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A Woodstock Ice Age, Pt. 5; the bottom of an old lake

On the rocks – The Woodstock Times, 2008

Updated by Robert and Johanna Titus

 

The Comeau, and plans for its development, have generated a lot of discussion in recent months. We don’t live in Woodstock. and it is not our place to voice an opinion, but it is proper for us to describe the geologic history of those 76 acres. And there is a lot of interesting geology there. Let’s focus, today, on some of the ice age history.

If you walk the Comeau trail, almost to its western end, you will find two earthen banks along the Saw Kill. If you know what to look for, there is a lot of ice age history to be seen there. Lots of streams display earth banks; these are formed when stream channel erosion cuts into the side of the riverbank and excavates into the “dirt.” In most cases there is little of great note and even a geologist will walk by without paying much heed, but not here.

If you look carefully, you will find that the earth is layered or stratified. It’s not immediately obvious, but it’s there. Careful examination will reveal more. Some layers, or strata, are light colored and relatively thick. Others are thinner and darker. The thick light layers are made mostly of sand while the thinner strata are mostly clay. This might not sound all that important, but it speaks volumes to the geologist.

  Varves

These horizons of sediment are referred to as “varves.” They are seasonal deposits that form almost only in ice age lakes. Now we are making progress. The sediments here take us back to the end of the Ice Age. At that time, summers were just getting warm enough to melt part of the great glaciers that had filled all of the area’s valleys. The valley of the Saw Kill was emptying of its ice. But, off to the east, there was still a large glacier: the Hudson Valley glacier.

That mass of ice served to dam the lower reaches of the Saw Kill valley and the dam was responsible for something that can be called Glacial Lake Woodstock. When you drive along Tinker Street, just west of the Comeau, you will observe a lot of flat landscape. That’s the floor of the old lake. And the stratified sediments within the Comeau were deposited on that lake floor.

  Lake Woodstock, Green

During summers it got warm enough, so the ice melted off of the lake’s surface. Then wind would generate currents within the lake. Those currents swept sand out into the lake and deposited it in the form of those thick, light-colored horizons; we call then “summer varves.”

During winters the lake surface froze over, and there were virtually no currents below the ice. During that time sand could not be moved around and the only deposition that did occur was of very fine, organic rich clays. Hence the origin of the thin, dark “winter varves” that we observe along the Saw Kill.

You can explore the old lake yourself. As we said, you can drive west from the Comeau and observe a lot of flat lake bottom. Bring a map along and you can map the lake bottom and really experience the lake. Some of the flattest lake bottom lies just south of the Saw Kill, across from the Comeau. Most of Bearsville was built on the western end of the lake bottom. Pretty much everywhere south of Tinker Street and west of Woodstock was lake bottom.

An obvious question is “how deep was the lake?” There is an answer to that question, and we will develop the argument for it in a future column. But for now, let’s just say that the lake level was at 880 feet in elevation. But the lake bottom, just across from the Comeau lies at just 600 feet. You do the math; the lake was 280 feet deep!

Drive down Tinker Street and look around at the flat lake bottom; that lake was big. Then look up 280 feet into the air 280 feet; that lake was deep. You have driven down this road so many times and you never guessed this, did you? It rather rearranges your sense of reality. But that is something that knowing a geological history is likely to do from time to time.

 

Reach the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”

 

 

Woodstock in the Ice Age, Part 3, High Tide. Dec. 23, 2021

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A Woodstock Ice Age, Part 3: High tide

On The Rocks; The Woodstock Times, 2008

Updated by Robert and Johanna Titus

 

There was a time when the very concept of the Hudson Valley did not mean very much, and it was not all that long ago, at least not in the way that geologists think about time. Let’s take a plane ride back 20,000 years ago. We are the mind’s eye, the human imagination, and we can do such things. We are flying from what will someday be Woodstock to what will be Kingston. It is a clear day, and we can see all the way to the horizon in any direction that we care to look. There is virtually nothing to see.

Looking straight down, we see a pool-table flat surface of white. We drop down and fly close to the “ground” (the mind’s eye can do such things) and only a little more detail becomes apparent. Now the whiteness is broken by a few dark fractures. We are close enough to tell that it is ice that we are looking at, and now we can also see some drifts of snow. But, for all practical purposes, this is a featureless and white Arctic landscape.

We rise up high into the sky, higher than before. Off to the east the white extends to the horizon with absolutely no blemish. That horizon shows the Earth’s curvature, but it is a white curve against a very pale blue. We look north and see exactly the same vision. Then we look west and there, at last, is the one blemish to the perfectly white landscape. The peak of Slide Mountain pokes above the ice; it is an island in a sea of ice.

The sight of Slide’s peak is a welcome one, but the view quickly generates a rush of awe. Slide rises to more than 4,000 feet in elevation and only just a little bit of its summit is showing; there must be a very large amount of ice. The conclusion is inescapable: there are thousands of feet of glacier beneath us. We used the word “Arctic” but we might better have called it Antarctic. There is nothing in the modern world to match what we are seeing except the vast whiteness of Antarctica. It is this notion that inspires such awe.

Millennia from this time, scientists will recognize this as one of the great glaciations of all history, and they will name this glacier the Woodfordian Ice Sheet. More than half of the North American continent is, on this day, covered with ice. We are the mind’s eye; we rise up thousands of miles above the surface and gaze to the north. Even this high there is nothing but white curved globe as far as we can see in that direction. Once again, a rush of awe overwhelms us.

To the south we do better. We are now high up enough to see the southernmost extent of the glaciation. The ice has reached into northern New Jersey and northeastern Pennsylvania. More ice has reached as far south as Long Island. Beyond the whiteness is a barren and desolate landscape. Someday scientists will call this bleak region a tundra or a “periglacial” zone.

Now we understand why the very notion of the Hudson Valley is meaningless. All of that valley, along with the Catskill Front, is buried in the thickness of the ice we see. It gets worse: off to the east both the Taconic and the Berkshire ranges are similarly submerged in ice. That is why the horizon to the east is so flat.

We continue our ice age flight back to the north. With our mind’s eye we operate a form of radar that penetrates the ice below. We can see the Hudson Valley below and we can see the Catskill Front and the Catskill Mountains. We are the mind’s eye; we can do such things as this.

We pick out Overlook Mountain within the ice and we drop down and pass down through hundreds of feet of glacier and arrive at the very peak of the mountain. Again, the mind’s eye can do such wondrous things. We watch as the moving ice is dragged across the knob of rock, found today just north of the fire tower. Boulders and cobbles litter the bottom of the ice, and these are dragged across the bedrock. They scour that surface and also carve very prominent striations into the rock. A polished and scratched surface is soon developed.

Overlook Mountain

Now, for us, the mind’s eyes, time speeds up and we feel the climate warming. We watch, again with awe, as the Woodfordian Ice Sheet begins melting all around us. In what only seems to us as the briefest period of time the peak of Overlook emerges from the ice. Now that knob of rock is left behind; its scratched surface remaining as a testimony to what happened here during the Ice Age.

You can see all this for yourself; go out and climb Overlook.

   Reach the authors at randjtitus@prodigy.net. Join their facebook page thecatskillsgeologist.com.

Woodstock in the Ice Age #2: South by Southwest Dec. 16, 2021

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Woodstock in the Ice Age; South by Southwest

On The Rocks; The Woodstock Times. 2008

Updated by Robert and Johanna Titus

 

We and many of our colleagues practice an art that doesn’t have a formal name. It should go by the name “rockcraft,” but to our knowledge that word is never used. Rockcraft must be related to woodcraft, both are outdoorsy pursuits. A person who practices woodcraft is familiar with camping out, especially in the wilderness. They know the plants and the animals and know how to read the signs and the seasons. They are well-versed in outdoors survival skills, mostly through experience.

People who know their rockcraft, are similarly experienced. After years of outdoors study, they know how to read the signs of the rocks. They are alert to what the rocks have to tell them. Rockcraft is a less known skill; there are no b\ Boy Scout merit badges in rockcraft. Also, rockcraft is not likely to help you survive if you are lost in the wilderness. But it is a very rewarding skill, simply for the understanding of what nature has to tell you about its distant past. In a way rockcraft is what this column is all about.

One of our personal favorite aspects of rockcraft is the pursuit of glaciers. Of course, there are no glaciers in this area and there have been none for about 14,000 years, but there once were and they can still be followed. The main thing to watch for in pursuing a glacier is the glacial striation. Advancing glaciers are likely to bulldoze away all or most of the soils that they overrun. having stripped the landscape down to bare rock, the ice scrapes across it. If, as is highly likely, the ice is carrying cobbles and boulders with it, then those rocks will gouge scratches into the bedrock as they are dragged along. This is the origin of glacial striations, among the most commonly seen ice age features.

If you know where to look, striations can be quite commonplace. Naturally any time you see bare bedrock, it is worth taking a look. We always watch for roadside outcrops. It is commonly the case that after the highway construction has cut into the bank, erosion will sweep the rocks clean and expose the striations. We also watch the tops of ledges; they are so common throughout the region and often reward us with striations. Then there are the tops of cliffs along the Catskill Front. We have found them at the top of Overlook Mountain and all along the escarpment trail.

Naturally, the striations will be aligned according to the direction of movement of the ice. So, when we find them, we can take a compass reading and when we have collected enough such readings in an area, we will be able to document the history of the flow of ice.

During the ice age, glaciers expanded out of northern Canada and drove their way into the northern United States, including the Hudson Valley. We can trace the path of that ice as it passed through this area. What you do is go out and watch for those glacial striations. We have been doing this for quite some time now and we think that we have collected enough data to form a firm opinion of which way the ice flowed.

And we found absolutely no surprises. The ice, here in the Hudson Valley, was funneled through the valley. The striations almost always line up close to a compass direction of south 30 degrees west. It’s sort of a chicken and egg issue here. The structure of the bedrock geology first dictated the alignment of the valley and steered the glaciers. But then, the glaciers scraped and eroded the valley as they passed through it. In so doing they enhanced the southwest lineation of the valley by straightening and steepening the great wall of the Catskill Front.

Even if there were no surprises in what we found, it was still nice to have good documentation of the flow of the ice and to further demonstrate the relationship between the Wall of Manitou and the glaciers that once flowed past it.

Contact the authors at ranbdjtitus@prodigy.net. Join their facebook page “The Catskill Geologist.”

The Zena Ice Field Dec 10, 2021

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The Zena Ice Field

On the Rocks; The Woodstock Times, 2009

Updated by Robert and Johanna Titus

 

The very first time we ever visited Woodstock, we entered by way of Zena Road. We slowed down at the wonderful view of Overlook Mountain. We remember a cornfield there and that added to the view. Some time later this field was threatened with development. Thankfully, the Woodstock Land Conservancy managed to save it and now the land and its grand view are, forever, just as they were and “have always been.” The site with its view is a very emblem of Woodstock itself. We can all be very glad it has been preserved.

But we are geologists, and we see a lot more when we pull over there and gaze north. We did so recently, and it was quite the experience. We saw the Zena field as it was 23,000 years ago. It was heavily forested then, and we could only see the top of Overlook. The forest was just what you would expect; there were oaks, maples and birch. There were a lot of chestnuts back then too. Many of these were enormous trees, there had never been any cutting in this forest; trees grew to great age and size.

As geologists we were blessed with being able to watch this forest for centuries, a lot of them. We noticed that the summers were getting shorter and grayer. They seemed to stop getting really hot; in fact, it was downright cool and cloudy. There seemed to be fewer warm weather birds. We thought there were fewer summer insects as well; we rarely heard katydids.

The winters were not all that cold though, but they too were overcast. It always seemed to be about 31 degrees out and snowing. We got to be a little weary of the snowfall, but it would not stop. As more centuries elapsed, we noticed that the trees atop Overlook seemed to sicken. Even in late August they seemed pale, even yellow. With more centuries I saw that some of them were dead.

Then down below, we noticed the same affliction in the forest of Zena. Their August leaves were small and yellow. Summer was just not warm enough to allow healthy growth of these trees. What was going on? We were the only humans in all of North America; there was nobody to go and ask.

Now we noticed that the snowfall was lasting into May and then June. The new snows were returning in October and even late September. We are used to climatic cycles, but our droughts are always followed by rainy seasons, our heat waves are balanced by cold spells. We were watching a one-way process. Woodstock was changing into a land without summer. Now the forests up on Overlook were all dead and the trees of Zena were dying as well.

There was something else. we saw weeks of weather when the skies were blue, clear, and cloudless while cold, very dry winds blew steadily out of the northeast. We wondered if there was something cold and dry in that direction. It was a relentless wind that got on our nerves after a while, but it would not stop.

The snows lay on the ground longer into the “summer” season. We saw dirty old snowdrifts in mid July. One summer the ground never thawed out and that was the year all the trees finally died.

Trees don’t make noise, but once they are dead all the noise makers soon leave. We watched as all the birds, all the noise-making insects and all the grunting animals left. The dead forest became unnervingly silent.

But real silence was rare; those howling dry winds soon desiccated the dead trees. Soon, the brittle twigs were blown down, then the branches and finally even the dry limbs crashed to the ground. The forest was a very noisy place . . . until only the tree trunks were left.

Later we heard a distant crashing and falling sound of a different sort, and then another. Soon this became routine, and we wondered what was going on. It took months, but then we found out. A great glacier was moving south, through the Hudson Valley and it was plowing down all the dead trees. Now, at last, we comprehended. When the glacier got to us, we climbed up upon it and reached its top. Now we had a better view of it all. As far as we could see to the north and east there was a flat, endless expanse of ice. It was a frightening sight. To the west and south, dead forests somberly awaited their destruction.

Then we looked up and beheld a horizon of ice rising above the top of Overlook itself. Soon, this great sheet of ice, thousands of feet thick, stretched from the western to the eastern skyline. Down below, the local ice mostly advanced westward; Woodstock was next.

Reach the authors at randjtitus@prodigy.net. Join their facebook page at “The Catskill Geologist.”

The Zena Ice Field

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The Zena Ice Field

On the Rocks; The Woodstock Times, 2009

Updated by Robert and Johanna Titus

 

The very first time we ever visited Woodstock, we entered by way of Zena Road. We slowed down at the wonderful view of Overlook Mountain. We remember a cornfield there and that added to the view. Sometime later this field was threatened with development. Thankfully, the Woodstock Land Conservancy managed to save it and now the land and its grand view are, forever, just as they were and “have always been.” The site with its view is a very emblem of Woodstock itself. We can all be very glad it has been preserved.

????????????????????????????????????

But we are geologists, and we see a lot more when we pull over there and gaze north. We did so recently, and it was quite the experience. We saw the Zena field as it was 23,000 years ago. It was heavily forested then, and we could only see the top of Overlook. The forest was just what you would expect; there were oaks, maples and birch. There were a lot of chestnuts back then too. Many of these were enormous trees, there had never been any cutting in this forest; trees grew to great age and size.

As geologists we were blessed with being able to watch this forest for centuries, a lot of them. We noticed that the summers were getting shorter and grayer. They seemed to stop getting really hot; in fact, it was downright cool and cloudy. There seemed to be fewer warm weather birds. We thought there were fewer summer insects as well; we rarely heard katydids.

The winters were not all that cold though, but they too were overcast. It always seemed to be about 31 degrees out and snowing. We got to be a little weary of the snowfall, but it would not stop. As more centuries elapsed, we noticed that the trees atop Overlook seemed to sicken. Even in late August they seemed pale, even yellow. With more centuries I saw that some of them were dead.

Then down below, we noticed the same affliction in the forest of Zena. Their August leaves were small and yellow. Summer was just not warm enough to allow healthy growth of these trees. What was going on? We were the only humans in all of North America; there was nobody to go and ask.

Now we noticed that the snowfall was lasting into May and then June. The new snows were returning in October and even late September. We are used to climatic cycles, but our droughts are always followed by rainy seasons, our heat waves are balanced by cold spells. We were watching a one-way process. Woodstock was changing into a land without summer. Now the forests up on Overlook were all dead and the trees of Zena were dying as well.

There was something else. we saw weeks of weather when the skies were blue, clear, and cloudless while cold, very dry winds blew steadily out of the northeast. We wondered if there was something cold and dry in that direction. It was a relentless wind that got on our nerves after a while, but it would not stop.

The snows lay on the ground longer into the “summer” season. We saw dirty old snowdrifts in mid July. One summer the ground never thawed out and that was the year all the trees finally died.

Trees don’t make noise, but once they are dead all the noise makers soon leave. We watched as all the birds, all the noise-making insects and all the grunting animals left. The dead forest became unnervingly silent.

But real silence was rare; those howling dry winds soon desiccated the dead trees. Soon, the brittle twigs were blown down, then the branches and finally even the dry limbs crashed to the ground. The forest was a very noisy place . . . until only the tree trunks were left.

Later we heard a distant crashing and falling sound of a different sort, and then another. Soon this became routine, and we wondered what was going on. It took months, but then we found out. A great glacier was moving south, through the Hudson Valley and it was plowing down all the dead trees. Now, at last, we comprehended. When the glacier got to us, we climbed up upon it and reached its top. Now we had a better view of it all. As far as we could see to the north and east there was a flat, endless expanse of ice. It was a frightening sight. To the west and south, dead forests somberly awaited their destruction.

Then we looked up and beheld a horizon of ice rising above the top of Overlook itself. Soon, this great sheet of ice, thousands of feet thick, stretched from the western to the eastern skyline. Down below, the local ice mostly advanced westward; Woodstock was next.

Reach the authors at randjtitus@prodigy.net. Join their facebook page at “The Catskill Geologist.”

The Comeau Hill at Woodstock Dec. 2, 2021

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A Woodstock Ice Age, Part 7 – The Comeau Hill

On The Rocks; The Woodstock Times, July 2, 2009

Updated by Robert and Johanna Titus

The Comeau is one of Woodstock’s most valuable and beloved properties. Its land use has, of course, been the subject of great controversy, and of many Woodstock Times articles, but no one has ever disputed that it should be there for the benefit of the residents. We have long believed that an appreciation of the geological history of a location adds greatly to its enjoyment, and we would like to continue on that theme today.

In an earlier article we described how this stretch of the Saw Kill Valley was once at the bottom of an ice age lake. Now we would like to focus on second ice age chapter in this area’s history. Most of the Comeau lies atop a sizable and broadly rolling hill. The soccer field is located precisely at the top of this hill. We had, for quite some time, struggled to understand the origins of this hill. Geologists are condemned to do such things.

Top of Comeau drumlin.

We really couldn’t fathom how this hill came to exist where it is. It is composed of Devonian bedrock at its eastern end, but the perfectly rounded shape to the west did not conform to what bedrock should look like. Sometimes this sort of problem makes your head hurt and that was the case until we hit upon a very possible solution to the problem.

If you read our last column then you learned about two hills lying southeast of Woodstock. These hills are known to geologists as drumlins. They were sculpted by the passing ice at the very end of the Ice Age. They are shaped like upside down spoon bowls. That makes them perfectly rounded at their tops.

We had not considered the possibility that the Comeau Hill had been a drumlin. But then, one day, we took another look at the satellite photo of the Saw Kill region, and it hit us. The Comeau hill was indeed a drumlin. It’s not a big drumlin but that is, we believe, what the hill amounts to.

  Comeau drumlin just right of center.

The two (or maybe three) drumlins lying southeast of Woodstock are full-sized, well sculpted drumlins. They display everything that you want to see in a drumlin. They record what may have been the third advance of the ice into the Saw Kill Valley. And that, it seems to be, is exactly what formed the Comeau hill. That final advance of the ice split into two lobes. One passed to the southeast while the other advanced further up the Saw Kill. It probably ran out of steam just a little to the west. That lobe made the hill.

Most geologists argue that drumlins form when a glacier advances across an older pile of ice age sediment and reshapes it into that spoon shape. Other geologists, however, argue that there is a second mechanism for making a drumlin. They make the case that a drumlin forms when a glacier rides over a knob of bedrock. The ice of the glacier can easily pass over the obstruction, but not without being altered in the process.

You see, there is usually a lot of water within a glacier of this sort; they are just very wet. That water cannot climb up over an obstruction and pass on to the other side. So, when the ice does reach the other side, it is a lot drier than it had been. Apparently, this robs the glacier of much of its ability to transport sediment. That sediment is smeared out on the downstream side of the obstruction and sculpted into a drumlin.

That seems to be the case here. Take a look at our satellite image. The Comeau drumlin, unlike the others in the region, appears to be an obstruction drumlin. The glacier encountered that eastern bedrock, I spoke of earlier and created the drumlin. Late at night in geology bars, we debate this sort of thing and not everybody ends up in agreement. But the Comeau hill strikes me as a very good argument for the obstruction hypothesis.

But the debate may be lost on most residents of Woodstock. What you can appreciate is the ice age origin of this lovely hill. When you are up there watching a soccer game or just walking around, please notice the gently rolling shape of the hill. Gaze west and appreciate the sculpting that went on here. Over the decades there have been a lot of sculptors living in Woodstock, but Nature was the first and that was about 14,000 years ago.

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

Glasco Pike #5 – The Catskill Delta

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The Glasco Pike #5: How long is time?

On the Rocks; The Woodstock Times

Updated by Robert and Johanna Titus

 

The one thing that geologists can truly claim is that we have a very well-developed understanding of the vastness of time. We deal in enormous amounts of time all the, well, time! Today we continue our own journey through the eons, one that has taken us along the Glasco Turnpike. We are looking at the history of Woodstock and all of Ulster County as it was during Devonian time, a little less than 400 million years ago.

Last time, we had reached a point one mile west of the Plattekill Bridge. There we saw a petrified river channel. We had entered into the realm of the Catskill Delta. That’s a great delta complex of the Devonian age; it is comparable to the Ganges Delta of today’s Bangladesh. Now we continue westward along the Glasco Turnpike on a journey which will carry us toward Overlook Mountain.

This trip of several miles will carry us uphill about 500 feet, but it will also carry us “uphill” through time. As you head this way as you pass the occasional outcrop of bedrock. For the most part these rock exposures are of sandstone. It’s the type of sandstone that we, around here, call “bluestone.” Each of these ledges is similar to the outcrop we saw in our last installment; they are all Devonian river channel deposits.

But there are so many of these deposits; it leads to a simple question: how can there have been so many rivers in the Woodstock area way back during the Devonian? And, as we learn more, the mystery gets even better. All of these ledges have a gentle incline to them; they dip to the west. That means that if we drive down the highway and pass one ledge and soon pass another, then we have, in fact, passed two successive ledges in a stratigraphic sequence. There is a sequence of inclined ledges arrayed down the highway. Each ledge represents an ancient river.

What this means is that, through time, many successive rivers flowed across the Catskill Delta. The delta, like today’s modern Mississippi Delta, was constantly sinking. As the old delta surface subsided, new rivers would flow across new surfaces, carrying with them new deposits of sand to make new bluestone. Try to appreciate this as you pass the many ledges along the Glasco Turnpike. You are passing through a stratigraphy, and you are passing through time, a lot of time.

That has been the point of our whole series of visits along the Glasco Turnpike. We have used this highway to make a journey, a Darwinian journey, through time. Let’s make a few stops or at least slow down a little.

Just 7/10’s of a mile west of the Rt. 212 intersection is an outcrop that displays a nice example of a river sandstone, which lies immediately above a fossil soil horizon. This is what happened there. There had been a delta plain surface which, over a period of time, developed a good thick soil. Then, probably very gradually, the delta plain subsided. A nearby river jumped its old channel, moved here and eroded its way into the soil that we see here. For a long period of time that river flowed this way and then, at a much later date, it jumped its banks and moved somewhere else. While at this location all the sands of the ledge you see accumulated.

Keep going west and just 1/10th of a mile west of Plochman Lane is another fine outcrop. The lower 2/3rds are made of strata of red silty sandstone. These might be considered as more fossil soils; they would remind you of Georgia red clays. That is pretty much what you would expect, considering that this was a tropical climate way back then. The rest of the outcrop is another river channel.

At Meads Mountain Road you can turn and drive uphill. If you wish, you can stop at the trailhead for Overlook Mountain. From there you can hike up to the top of the mountain. All the way, you will continue to pass more ledges of river channel bluestone. Commonly you will see more horizons of red fossil soils. You are traveling upwards through the sediments of the Catskill Delta, once one of the world’s great delta systems. You are watching as it gradually subsided and gradually accumulated more sediment. That took a lot of time.

And, once again, that is the whole point of our journey. We have traveled, these past five chapters, from Glenerie to the top of Overlook Mountain. We have watched as a shallow tropical sea came to deepen into an abyss. Then we watched the waters shallow again and soon a huge delta complex overwhelmed the whole Catskill region. From the top of Overlook Mountain, we can gaze back towards Glenerie and now have a real understanding of what the rocks between here and there represent. We have an inkling of the enormous amount of history that has unfolded before us. Now we also have an inkling of how long is time.

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

The Glasco Pike #4 – A Fossil River

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The Glasco Pike #4: A Fossil River

On the Rocks; The Woodstock Times

Updated by Robert and Johanna Titus

 

We have been exploring time itself over the course of the past several columns. Physically, we have been moving westward along the Glasco Pike. But, in terms of time, we have gone back to the early Devonian time period and have been moving forward. Our goal is to look at our local geological history in the way that geologists see it. We are looking at several million years of time and history. This is history that took place during the Devonian time period. Young world creationists do not believe in the Devonian. They commonly attempt to fit their view of geological history into the catastrophe of the Noah’s Flood. Our job is not to criticize that but to explain the point of view of geologists. Let’s continue our journey.

We are going to drive about a mile west of our last stop where the Saw Kill crossed the Glasco Turnpike. We will climb a hill and then, to the right, is a fine ledge of rock. Parking is tricky here and we don’t want anyone to be hurt so use good judgment. You might just glimpse and run. It’s best to view the ledge from across the highway. When you do so then you can begin to see what these sandstones represent. They make up a fine cross section of an ancient river channel. Take a good look; you will see the channel is deepest in the middle and it shallows both left and right.

This is a petrified river. That is likely to be a novel idea for most of you. There are petrified trees and petrified dinosaurs, but a river? Who has ever heard of such a thing? Well, Catskill area geologists have, and they have heard of a lot of them. When we left off last time, we were watching the Woodstock area as it was rising out of the sea. Our view of the outcropping along the Saw Kill showed a shallowing sea. The strata at the top of that outcrop formed near the ancient shoreline. If that interpretation is correct then it cannot be much of a surprise that younger, overlying rocks should display evidence of having formed in a terrestrial landscape. What is more “terrestrial” than a river?

We have entered into the realm of the great Catskill Delta. It is a petrified delta and there we encounter another one of those surprising phenomena. Yep, there are petrified trees and maybe petrified rivers but a delta!? Look out the window and up into the Catskills. Try to imagine that the whole thing is a petrified delta. Kind of changes your perspective on things, doesn’t it?

The best way to come to understand the Catskill Delta is to get out a good map of Bangladesh. That Asian nation has been developed upon the Ganges River Delta. A good map will show a landscape dominated by scores of rivers, big and small, all emptying into the Bay of Bengal. Our little petrified river was very similar; it was one among scores of rivers crossing the Catskill Delta and emptying into a body of water called the Catskill Sea. Our river’s waters had descended down the slopes of the Acadian Mountains: a great range of mountains in what is today New England. Mountain streams had eroded into the Acadians and turned a great deal of mountain into sand. Our river had carried a lot of that sand as a channel deposit. See top of our first photo.

When you look at a river, it appears to be something that will last forever. Who can possibly imagine the Saw Kill or the Esopus Creek not being where they are? But rivers don’t last forever; someday even the Hudson will disappear. It’s easier to lose a river on a delta. There rivers have a habit of jumping from one site to another. During great floods, a river can be diverted of to a new direction, leaving its old channel abandoned. This is, no doubt, what happened to our little petrified river. Its flow of water jumped to a new site and went in a new direction and the old channel sands were left to slowly petrify. All memory of that river was lost until geologists came along and recognized what is there, along the Glasco Turnpike.

Charles Darwin is remembered mostly as a biologist, but he was a very good geologist as well. He would have understood the story of the Catskill Delta and this view of rocks would have fit very nicely into his mindset.

Young Earth creationists will likely have a problem here. If the Catskills are a great petrified delta, then that is something that must have taken an enormous amount of time to have been deposited. A mere 6,000 years is not going to be enough time, geologists think that it took many millions of years. And that is the point of this whole series of columns; We am laying out the evidence. We report and you decide!

Contact the authors at randjtitus@prodigy.net. Join their facebook page “The Catskill Geologists.”

 

 

 

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