Hudson Valley Climate & Species Changes

Lake Mohonk Mountain House, on the Shawangunk Ridge in the mid-Hudson Valley of New York, has long kept an invaluable record of daily weather conditions and phenological changes in the area.  Phenological changes are dates of periodic biological phenomena like the first appearance of certain migrating bird species in the spring, the first flowering of specific plants, the singing of spring peeper frogs, etc.

Keeping of these records started in 1896 with naturalist Daniel Smiley and has continued unchanged until the present day (these tasks are currently overseen by naturalists at the Mohonk Preserve).  Last year, we had Shanon Smiley (left) deliver a talk at SUNY Ulster for the John Burroughs Natural Science Lecture Series on what this data tells us about local climate change.  The good news is that she recently made this talk available online off the Preserve website (scroll down, link at right).  Here's the direct link to download the presentation.

Climate Change at Mohonk: Weather & Species

About a half-hour long and it's worth watching if you're interested in what some of the evidence is for climate change in our local area.

Oklo - Part I

Oklo is a region in the west African equatorial country of Gabon.  What makes it notable to geologists is that it is the site of an unusual event which took place some two billion years ago.

Back in 1956, when Gabon was a French colony, prospectors from the Commissariat à l'énergie atomique discovered uranium deposits in the Oklo region near the city of Franceville in the southeastern part of the country.

France at the time was developing both reactors for nuclear energy as well being engaged in nuclear weapon research (they developed a nuclear bomb in 1960).

France mined uranium at Oklo for domestic nuclear reactors for 40 years until the deposits were exhausted and the mine closed.

In 1972, however, French physicist Francis Perrin noted an unusual thing when routinely testing the uranium from Oklo.

In order to understand what Perrin discovered, we have to first take a little digression on isotopes.

Let's start with atoms.  Everyone should know that atoms have a nucleus composed of protons and neutrons and the nucleus is orbited by electrons.  This is the simplified Bohr model of the atom (named for the famous Danish physicist Niels Bohr).  Protons have a positive charge, electrons have a negative charge, and neutrons are electrically neutral.  At right is a simple model of a carbon atom.

Now think of the periodic table of the elements.  Each entry on the table is an element.  Elements are atoms that differ from each other by the number of protons in their nucleus (this number is called the atomic number).  Hydrogen (H), for example, has an atomic number of 1 on the periodic table and has one proton in its nucleus.  Add another proton and you have helium (He).  Toss in 6 protons and you have carbon (C) as shown above.  Uranium (U) has 92 protons in the nucleus.

While the number of protons determines the element, atoms of the same element can have differing numbers of neutrons in the nucleus.  These different forms of the same element are called isotopes from the Greek roots isos (ἴσος "equal") and topos (τόπος "place") because isotopes of a single element occur in the same place on the periodic table.

Different elements have differing numbers of naturally-occurring isotopes (the theory behind all of this is complex and beyond the scope of this post).  Some isotopes are heavy in that they contain more neutrons in the nucleus than protons whereas others are light in that they contain fewer neutrons in the nucleus than protons.  In addition, some of these light or heavy isotopes are radioactive meaning they spontaneously decay into other elements over time (the rest of the isotopes are stable and don't decay).  The time it takes radioactive isotopes to decay is given by their half-life - the amount of time it takes for half of the isotopes in a sample to decay.

Two naturally-occurring isotopes are uranium are U-235 and U-238. The 235 and the 238 are the mass numbers which denotes the number of protons and neutrons in the nucleus of these isotopes.  Since all uranium has 92 protons (the element's atomic number), U-235 has 235-92 or  143 neutrons and U-238 has 238-92 or 146 neutrons.  Both of these isotopes are heavy and radioactive but they each have a different half-life.  The half-life of U-235 is 703.8 million years and the half-life of U-238 is 4.47 billion years.  Quite a difference.  Since they have different rates of decay, the ratio of U-235/U-238 will change over time (that ratio will decrease since U-235 decays more quickly).

In natural uranium deposits today, U-235 is about 0.72% of the total.  As we go back into geologic time, however, this ratio will increase.  Around 1.7 billion years ago, that ratio would have been around 3.1% (the other 97% being U-238.  Another important different between U-235 and U-238 is that U-235 is fissible.  This means that it will split apart when bombarded by free neutrons - a process called nuclear fission.

n + U-235 => Ba-141 + Kr-92 + 3 n

A free neutron (n) colliding with U-235 will split it into Ba-141 (barium) and Kr-92 (krypton) plus 3 free neutrons.  These 3 free neutrons can than fly off and split other U-235 isotopes in a self-sustaining chain reaction.  This process also releases energy hence its use in nuclear reactors (a LOT of energy - a chunk of U-235 the size of a grain of rice can produce as much energy as 3 tons of coal!).

Now back to the story of Oklo and the French physicist Francis Perrin.  What he found when testing samples from Oklo is that the ratio of U-235 wasn't around 0.72% as expected.  It was lower.  Further testing showed some samples were as low as 0.44% and there were similarly lower than expected ratios of other isotopes like neodymium (Nd) and ruthenium (Ru).  What caused these anomalously low ratios?

Well, it turns out that these ratios would be exactly what you would expect if these isotopes were in a nuclear reactor.  It also turns out that back in 1956 a chemistry professor at the University of Arkansas named Paul Kazuo Kuroda predicted that these types of nuclear fission reactions could occur naturally under favorable conditions.

Further research confirmed that nearly 2 billion years ago, nuclear fission reactions similar to what occurs today in the containment vessels of nuclear reactors, naturally developed in a mass of uranium ore at Oklo.

In my next post, I'll discuss a bit more about the geology of this unique site.

The Eye of Africa

Deep in the western Sahara Desert, in the country of Mauritania, is a spectacular circular structure that can be seen from space called the "Eye of Africa" or the Richat Structure (Guelb er Richat).

This structure is about 50 km (30 mi) across and was only discovered in the mid-1960s when Project Gemini spacecraft observed it from orbit.

The Richat Structure in Google Earth (21°07'30" N, 011°24'00" W)

Oblique view from Google Earth

It's pretty impressive.  Check it out in Google Maps and you'll see it's visible as you zoom out to orbital distances.

So what the hell is this structure? "Theories" on the Internet abound. Here are a couple of comments I saw on one web site:

I have a suggestion. It looks like a hole that could have been opened up when God flooded the Earth. “In the six hundredth year of Noah’s life, in the second month, the seventeenth day of the month, the same day were all the fountains of the great deep broken up, and the windows of heaven were opened.” -Genesis 7:11 Later God plugged the holes: “The fountains also of the deep and the windows of heaven were stopped, and the rain from heaven was restrained” – Genesis 8:2

There can be no question that it is a standing shock wave. It is well known that it is not a result of direct impact. I have a theory that I have not seen posted elsewhere. I think it is a shockwave as a result of a large object impact at the antipode of this location. The current antipode to the Richat Structure is East of the Coral Sea. Tectonic plate movements may have shifted the actual impact. This makes the most sense to me. The structure is simply too symmetrical and undulating to be anything BUT a shockwave. If this is correct, it would have formed very rapidly and would have been incredible to witness. 

What about it being a wortex generated by dominating winds in the area?

Looks like a crash landing site. From what exactly? That’s an interesting thought. 

Its Earth asshole!

(OK, maybe the last comment wasn't serious!)

This is why you have to be careful about what you read on the Internet, boys and girls. Lots of people have crazy ideas based on nothing but ignorant, wild-ass speculation.

If you have a lot of money you don't know what to do with, it is possible to do a Land Rover 4x4 tour of this area. The problem, however, is that the Richat Structure is so big that you can't really see it from the ground.   That's why it wasn't even recognized until the Space Age.  Here are
a couple of images from the ground showing not much more than rocks and hills.

Geological circular features like  the Richat Structure are generally caused by one of three things - a meteorite impact, volcanic activity, or a domical uplift from an igneous intrusion.

When this structure was first noticed, it was thought to be a meteor crater. Once geologists got out there, however, it was determined that this structure had none of the characteristics that would have been expected from an astrobleme (impact crater).

The sedimentary strata surrounding this structure is upwarped, but not heavily broken up or overturned as is common in an impact crater. The multi-ringed structure of sedimentary rock without a depressed center is also not typical of craters. Large impacts also alter the crystalline structure of quartz grains in the surrounding rocks (called shock metamorphism) and there's no sign of that here.

[Dietz, R.S., et al. 1969. Richat and Semsiyat Domes (Mauritania): Not Astroblemes. Geological Society of America Bulletin 80: 1367–1372]

Geological fieldwork also showed that this structure is not a simple volcanic caldera (a large volcanic crater).  There is, however, evidence of past igneous and volcanic activity here (movement of molten rock - magma - in the subsurface).

Geologically, the structure is composed of three nested rings dipping outwards from the center.  They are composed of a sequence of  sedimentary rocks dating from the Upper Proterozoic Period (about 650 million years ago) to the Ordovician Period (about 450 million years ago).  The center of the structure is a limestone shelf with a lens of breccia (rock created from angular fragments of rock cemented together).  The whole structure is intruded by various types of volcanic rocks.

So what caused this?  A proposed mechanism (G. Matton, 2008) for the formation of the Richat Structure is as follows:

In Stage 1, prior to 100 million years ago, there was an intrusion of magma from the lithospheric mantle below the continental crust.  This intrusion domed up the overlying sedimentary rocks and formed radial and ring dike fractures above the intrusion.

In Stage 2, around 100 million years ago, there's reactivation of the magma chamber and the intrusion of different composition magma.  Groundwater circulating through the fractured, overlying rocks gets heated by the hot igneous intrusion and acidic leading to the dissolution of the overlying limestone.  The limestone collapses into sinkholes and gets cemented into a breccia.

In Stage 3, more igneous activity as magmas rise and interact with either shallow groundwater or surface water lakes in the center of the structure and explosive activity leads to collapse of the central part of the structure, much like a piston in a cylinder.

In Stage 4, erosion creates the circular, tilted layers (cuestas) of resistant quartz sandstone and exposes the central part of the structure where the limestone breccia and volcanic rocks occur.  Earlier radial and ring dikes are exposed in places.

All resulting in this.

NASA Landsat 7 image of the Richat Structure

Really cool!

Obama Care & Adjuncts

Just about every college and university relies on both full-time and adjunct instructors to teach classes. Adjunct instructors are part-time faculty who are basically hired on a semester-to-semester contractual basis to teach specific classes. It truly is an exploitive system for a number of reasons.

The amount of pay adjuncts receive is low (at our institution it currently ranges from around $2,200-$2,500 for a three-credit course before taxes - the higher value for adjuncts who have taught at least 24 three-credit courses!). Try to put together a living wage this way. Just to get above the $11,175 (2012) poverty line, you would have to teach a minimum of 5 classes a year - even if you were at the high end of the pay scale. To get above $20,000 a year (before taxes), you'd have to teach 8 three-credit classes. Guess what, you can't teach 8 three-credit classes a year at most colleges due to contractual restrictions that keep adjuncts below 12 credits per semester (7 three-credit classes would be the limit).

Let's even look at this even closer. The so-called Carnegie model assumes, for both faculty and students, that a three-credit class involves nine hours of work - two hours outside of class for every hour in the classroom. For students, those two hours are for studying, reading, homework, etc. That's why 12-15 credits a semester is considered full-time for a student. For faculty, those extra hours are for lecture preparation, grading, discussions with students outside of class, etc. So an adjunct faculty member teaching a three-credit course making $2,500 (highest end of pay scale) is paid for working 9 hours per week for a 15 week semester. That's $2,500 for 135 hours or $18.50/hour.

Doesn't sound too bad, right?

Keep in mind, however, that this is not full-time work so it doesn't add up to much. Adjuncts need to teach at multiple colleges (due to restrictions on how much they can teach at any one college) to make enough money to survive so spend lots on gas and wear-and-tear on their cars (especially in rural areas like mine). Each semester they have to struggle to fit together class schedules at different colleges. Needless to say, they get no benefits (health or otherwise). They also have no job protection and may have classes canceled at the last minute.

As mentioned above, adjuncts are also contractually restricted to generally teaching less than 12 credits a semester (4 three-credit classes). This varies from college to college. Why the restriction? If it didn't exist, some colleges would staff the entire campus with adjuncts and never pay anyone benefits or a living wage. Even with this restriction, the college where I teach has 1/3 of the faculty as full-time and 2/3 as adjuncts. This is not good for students (see my previous post on this) but an economic reality of higher education today given the public and politicians do not support public higher education in this country (not how it counts, with adequate public funding).

We have adjuncts at our community college who have PhD degrees in their field of study and sometimes tens of thousands of dollars in student loan debt! Working for essentially minimum wage. Most of them do it because full-time faculty jobs are very hard to get. Many of them hope to get a full-time position at some point. Most of them won't. It's a terrible system.

This terrible system will get even worse in January of 2014. The reason is that Obama's new Affordable Care Act regulations will require companies to provide benefits to those employees working 30 or more hours a week. Because of the Carnegie model mentioned above, adjuncts teaching 10 credits or more now fall under this restriction. Guess how companies will deal with this new law?

Brain-dead politician: "Uninsured working people who can't afford private insurance is a problem. Hey, let's solve it by passing a law saying you have to give health insurance to part-timers working 30 hours or more a week."

Chief financial officer at a company: "Part-timers are not allowed to work 30 hours or more a week anymore."

Result: Poor working people without insurance become even poorer!

IT'S COMPLETELY FUCKING PREDICTABLE!!!

Our college, along with many if not most others, will cut adjunct hours beginning in January 2014 and restrict them from a maximum of 11 credits/semester to a maximum of 9 credits/semester (a difference of up to five grand in their pay!).  It's even worse since many math and English adjunct instructors at our school also work at the college's math tutoring and writing centers.  These hours now count toward that 30 hour limit.

 

Adjunct faculty will now be screwed over yet again.  Is it too much to ask politicians to think through the consequences of their half-assed laws?