Watkins Glen

It's been a while since I posted but, as usual, things have been busy.  I don't get pay, recognition, or much else for writing a blog - it's mostly for my own benefit and to encourage my writing.  If others find it interesting or useful, that's an extra benefit!

Anyway, a few days ago, my family and I, along with another family, spend a couple of days at Watkins Glen (camping in the State Park - yes, it was raining much of the time).  The town of Watkins Glen is located at the southern end of Seneca Lake, the largest of the Finger Lakes in central New York.  While many people may associate the town with NASCAR racing (sorry, simply don't see the appeal), its most interesting feature is a stream-carved gorge now preserved as a State Park.

I'm in the beige rain jacket.  My wife has the white sneakers.

The gorge was certainly known to the native Seneca Indians but its name comes from Dr. Samuel Watkins and his brother John who acquired land in the area in the 1850s (the town was named "Watkins" in 1854 after John's death).  In 1863, the Glen was opened to the public as a privately-run tourist operation until it was purchased by the State in 1906 and it became a state park in 1924.  The word "Glen" was also added to town name of "Watkins" in the mid-1920s, capitalizing on the tourist appeal of the area.

Satellite image of Finger Lakes (Lake Ontario at top).  Small red

dot at southern end of Seneca Lake indicates the town of Watkins Glen.

A beautiful trail with 800+ steps runs 1.5 miles and 500 feet of elevation gain through the Glen and I highly recommend a visit if you're in the area.

As a geologist, I appreciate such places on two levels.  On one level, like everyone else, I enjoy the unique scenic beauty of the area.  But, since I'm fortunate enough to be a geologist, I also see and appreciate a lot of other aspects of the Glen that most people may never notice (of course, a botanist would notice all the plants or an entomologist insects - things I might be oblivious too as I walk around the world).

Anyway, let's talk a bit about the geology of Watkins Glen.  The geologic story of the Glen took place in two acts, each separated by almost 400 million years of time.  It all started during a time geologists call the Late Devonian Period (Frasnian Age), some 375 million years ago.

The world was very different back then.  Below is a paleogeographic reconstruction of North America during that time.  The equator, and the direction of north, is shown.  State outlines give an idea of where things are today.

Reconstruction from Ron Blakey, NAU Geology

Let's look at a close-up of New York State.

The red dot denotes the Finger Lakes Region of central New York.  It was under shallow seawater during this time in a subtropical climate zone just south of the equator.  In eastern New York into New England there was a mountain belt which geologists call the Acadian Mountains.  They resulted from the collision of a small microcontinent (which is now permanently attached as New England) with proto-North America.  Just as India colliding with Asia in more recent times thrust up the Himalaya, the collision of Avalonia (the microcontinent's name) with Laurentia (what geologists call proto-North America) formed the Himalayan-sized Acadian Mountains.

As these mountains eroded, the sediments were washed westward into that shallow sea.  Over time, land built outward in a large wedge called the Catskill Delta.  The horizontally-bedded conglomerates, sandstones, and shales of the present-day Catskill Mountains and Allegheny Plateau to the west were formed from these sediments shed from the Acadian Mountains.

From The Earth Through Time by Levin

We know these sedimentary rocks in the Watkins Glen area were formed from sediments deposited underwater because they contain various types of marine fossils.

Clam fossils from the Finger Lakes Region

Some of the sandstone layers in Watkins Glen also have ripple marks preserved.  These are the same types of ripples one sees today under shallow marine water in sands (I got very excited to see the ones below on the main trail through the Glen).

Symmetrical ripple marks on the rock walkway.

Over tens of millions of years, sediments accumulated in this environment and were buried deep enough for the soft sediments to be lithified into sedimentary rock (and preserve the remains of ripples and ancient seafloor organisms as fossils).

The next part of the story of Watkins Glen is more recent.  These once-buried rocks were eventually brought back to the surface by erosion of overlying rocks and sediments.  When buried, these rocks were under pressure.  When brought to the surface, pressure was released and they expanded.  When expanding, two sets of fractures developed from the tensile (pulling apart) stresses forming what geologists call an orthogonal joint set (fracture sets at right angles to each other).  These are easy to see in the cliff walls of the Glen.

Joints in the cliff wall of the gorge.

In this area, the joints are generally oriented ENE-NNW.  When rock is eroded by flowing water or glacial ice, the joint directions are preferentially carved out because the rock is weaker in those directions.  Let's look at a terrain map of the area showing topography.

Google maps view of Watkins Glen area

Note that Seneca Lake is oriented NNW and Watkins Glen is oriented ENE at right angles.  That's not a coincidence.  They were preferentially carved along the regional orthogonal joint sets.  Most people probably know that the Finger Lakes were carved during the last ice age during the Pleistocene Epoch of geologic time (2 million to about 10,000 years ago).

Let's imagine what this area looked like 10,000 years ago as the great glacial ice sheets melted away.  Seneca Lake was a deep glacial trough (close to 600 feet deep at its deepest) filling with glacial meltwater.  Glen Creek flowed into the deep trough from higher elevations to the west as a hanging valley (perhaps a spectacular waterfall at some point).  Over the past 10,000 years, Glen Creek has been cutting down into the horizontal layers of sandstones and shales resulting in a deep gorge with stepped waterfalls, scalloped walls, and potholes - Watkins Glen.

Stepped waterfalls (and a side tributary)

Scalloped walls and potholes of the Glen

Tomorrow, I'll post a brief story of the 1935 flood which devastated this region.

Panther Mountain impact structure

After earning my Master's degree in geology at the University of Albany in the early 1990s, I worked for a couple of years for the New York State Geological Survey down in the State Museum.  One of the geologists there at the time, and a hell of a nice guy to younger geologists like myself, was Dr. Yngvar Isachsen (since deceased).

Yngvar was well known for his work in the Adirondacks but, at the time, he was interested in a circular feature up in the Catskills centered around Panther Mountain.  He first noticed this feature in satellite images from the early 1970s, and it piqued his interest, but it wasn't until later that he started to more formally investigate.

Yngvar worked at the Survey well into his 70s and could outhike people half his age!

Let's go to Google Maps to view the area around the Ashokan Reservoir of New York.

Now let's switch to satellite view to see what Yngvar noticed (it's easy now, not so easy to view satellite images back in the 1970s!).

See that circular feature just northwest of the reservoir?  Let's zoom in a bit.

This feature is formed by the Esopus Creek (northern and western sides) and a tributary of the Esopus called Woodland Creek (southeastern side).  Roads and homes were, of course, built along the stream valleys here in historic times.

The Panther Mountain Asteroid (Robert Titus)

Circular features like this are generally caused in three geological ways - volcanic calderas, domical uplifts, or meteor impact craters.  So what's forming this feature?

Well it's certainly not a volcanic caldera - the geology is all wrong.  There are no volcanic rocks anywhere in the Catskills and we know that area is simply composed of essentially flat-lying sedimentary rocks - shales, sandstones, and conglomerates.  Hike anywhere in the Catskills to see them.

What about a domical uplift like, for example, the Adirondacks a bit further to the north or the Black Hills of South Dakota or the Ozarks of Missouri?  Well, these are generally caused by intrusions of igneous rocks like granite which push up the surrounding sedimentary strata.  Again, the geology is all wrong.  No core of igneous rock here and no tilted and folded sedimentary rocks along the flanks.  Everything is flat-lying.

How about a meteor crater then?  At first glance, this looks all wrong too since the area is high and mountainous in the middle. 

Panther Mountain

Everyone knows that craters are depressions.  Not so fast.  You have to think like a geologist.  What we see today is simply the modern landscape.  This area looked very different in the geologic past.  What if a meteorite struck here before the mountains even existed (yet still left a signature circular outline)?

Well, to test his hypothesis, Yngvar started doing some fieldwork and research over the span of several years (mostly in his spare time).  Walking around the Esopus and Woodland Creeks, he noted extensive jointing (joints are what geologists call fractures) in the bedrock of the streams. 

The joints were spaced about a foot apart there, some 10 times closer than jointing elsewhere in the surrounding rocks.  That's what governed the circular course of the creeks - water will preferentially erode away rock where it's weaker and so areas of the bedrock with more frequent jointing will eventually form creek valleys.  The real quest was why the jointing formed a circular pattern here?

Another clue came from old gas well cuttings that were found in the State Museum archives.  Turns out that other had noticed the circular pattern and thought it indicated a domical uplift associated with natural gas formation.  A 6,000 foot deep well was drilled but didn't produce enough gas to make it economically worthwhile (fortunately for those of us who love the wild forests of the Catskills).  Cuttings from the well were still bagged and archived so Yngvar and some graduate students started looking at them under a microscope.

What they found supported the idea of an ancient meteorite impact.  Iron-rich glassy spherules (left) and shocked quartz crystals (right).  The spherules form when iron meteorites impact, vaporize, and then rain out little spherules which settled back to Earth.  The shocked quartz forms when the crystalline lattice of quartz mineral grains experience shock waves and rearrange in parallel lamellae which can be seen in polarizing light under a microscope.

Both of these features are excellent supporting evidence for a meteorite impact.  Another piece of evidence came from an instrument called a gravitometer.  These are sensitive instruments that measure the Earth's gravitational field.  Higher density rocks in the subsurface will result in a stronger gravity field and lower density rocks will result in a lower gravity field.  The rocks under Panther Mountain have a lower density which is consistent with broken rocks (breccia) expected in a meteorite crater.

Piecing it all together gives the following scenario. 

Some 400 million years ago (before the pile of sedimentary rocks that became the Catskills formed), a large meteorite slammed into the shallow subtropical sea that once existed here (we know that because we have limestones of that age chock full of marine fossils!).  The crater eventually filled with broken rock (breccia) and sediments.

To the east, the Himalayan-sized Acadian Mountain rose due to the collision of a microcontinent that became what we today call New England.  As these mountains eroded away, the sediments washed down to the west to form the Catskill delta system - a thick wedge of sedimentary rocks that today we see as the shales, sandstones, and conglomerates of the Catskill Mountains.

As broken rock in the crater settles, fractures (joints) develop above the rims of the crater.  Glacial erosion during the last ice age and modern stream erosion has formed the present-day topography of the Catskill Mountains (not true mountains, by the way, but geologically a dissected plateau) and the joints which formed about the crater rim controlled the erosional course of the Esopus and Woodland Creeks.

Do we know this with 100% certainty?  No.  But it's a model that is consistent with the evidence and is the best hypothesis we have to explain this feature.  Until someone comes up with more data (targeting drilling might give more, but it's expensive to do) or comes up with a better explanation that fits the data, this is what most geologists are going with (some are still skeptical).

You have to admit, it's a cool idea?  Imagine a giant meteorite crashing down right in our own backyard!  Well, maybe not so cool if you are around when it happens...

So, how big was this impact?

H. Jay Melosh, a geophysicist at Caltech, has published equations to calculate such things given a variety of factors (density of the meteorite, velocity of the meteorite, angle of impact, type of bedrock impacted, etc.).  Let’s assume a nickel-iron meteorite with an average density of 7,800 kilograms per cubic meter, a conservative impact velocity of 20,000 meters per second (almost 45,000 miles per hour), and a vertical impact coming into a shallow Devonian sea and striking a limestone seafloor.  Given these assumptions, the impactor would have a diameter around 250 meters (about 820 feet).  A meteorite this size would impact with an energy equivalent to 1,800 megatons of TNT – the combined energy of over 138,000 Hiroshima-sized (13 kiloton) atomic bombs!

This obviously would have been a traumatic event for the marine invertebrates living in that sea and would have likely affected the global climate for a time.  Such impacts shoot up a lot of debris into the stratosphere where it’s spread by jet-stream winds to eventually encircle the Earth.  This dust will then reflect some of the Sun’s energy away resulting in a several-year-long cooling of the Earth’s atmosphere.  This is sometimes called the “nuclear winter” effect after a number of studies on the effects of a (hopefully) hypothetical large-scale nuclear war; an event which would also throw significant amounts of dust into the stratosphere.  Over the past few decades, researchers have recognized more and more ancient meteorite impacts in the geological record leading us to wonder when, not if, we’ll be hit again.  Yet we continue to cut NASA's budget as they try to discover monitor the orbits of Earth-crossing asteroids!

Giant's Ledge

Hiked up to Giant's Ledge today with some nice folks from the Meetup.com group Ulster County Outdoors.  Typical Catskill's hike, mostly uphill one way and downhill the other with a rocky trail.  The views from Giant's Ledge were well worth it, however.

Here's a panorama from the ledges - one of the best views in the Catskills.  Nice cirque (bowl-shaped depression carved by glaciers during the last ice age) over by Wittenberg and Cornell on the right side of the panorama.  Click here for a big version.

Also quite a few wildflowers along the trail.

 

Purple Trillium (Trillium erectum) & White Trillium (Trillium grandiflorum)

 

 

Trout Lily (Erythronium americanum) & Spring Beauty (Claytonia virginica)

 

I should write about nearby Panther Mountain, site of a possible ancient meteorite crater, but it will have to wait for another day.

Hydrogen

So, we've all heard of hydrogen.  First element on the periodic table.  Simplest atom with one electron orbiting one proton.  Logical symbol of "H" for the element.  I do have some vague memory (well, I only remember it because I spilled acid all over my hands - there's a reason I'm not a chemist) of making hydrogen gas in chemistry lab in college by pouring sulfuric acid on metallic zinc (H₂SO₄ + Zn => ZnSO₄ + H₂) but I never thought much about the name.

Anyway, I was reading a book the other day and it was talking about early experiments in chemistry.  Back in the mid-1700s, it was discovered that you can produce "flammable air" (hydrogen is flammable - think of the Hindenburg) by reacting metal filings (they used iron) with acids.  Furthermore, this "flammable air" produced water when burned in air (2H₂ + O₂ => 2H₂O).  The famous French chemist Antoine Lavoisier (1743-1794) named the gas hydrogen from the Greek words ὕδρω (hydro) meaning "water" and γενῆς (genes) meaning "creator" since it formed water (more trivia - Lavoisier was guillotined during the French Revolution for political reasons at the age of 50 - a waste of a great mind).

 

Hydrogen is a "water former" when you burn it in oxygen.  Obvious and it makes sense.  Just never thought about it before.  I have no idea why it interests me to learn little bits of trivia like this, but it does.  Guess I'm strange.