Thursday, July 30, 2015

Snow White and the 16 Columns

In Santa Cruz, I live in a beach town.  In Eilat, I work in a beach town.  In both places, I spend a good deal of my time in the lab.  There are labs, and then there are clean labs.  The difference?  Well, apart from clean being just what they are (clean), they stay that way by following a laundry list of procedures to keep dust, hair, and lint out of samples (which destroys the data).

In the case of the cleans labs at Santa Cruz and IUI, the main cause of concern is metal.  These labs focus on trace metal chemistry meaning that the scientists are studying tiny, tiny, tiny amounts of material containing things like lead, uranium, and thorium.  These can exist as minute quantities in many things we use in our daily lives such as steel doors, brass handles, pipes and wires, and electronics.  Because of this, clean labs tend to be made almost entirely of plastic.

In addition, the protective equipment I must wear in the lab has two purposes.  It keeps lint from my clothes or hair from my head  from floating around the lab and contaminating the space, and it protects me from the many types of acid used to study metals.  In this picture, I'm wearing a hair net, gloves, and a Tyvek suite which keeps my clothes and body from contaminating samples.


I do all of my work wearing this outfit.  As I said, clean labs mostly use plastic, and one of the stars among the plastic world is Teflon.  Yep, Teflon, the non-stick coating with which you may be familiar.  It's quite a dense plastic, and the non-stick properties are useful when dealing with drops of liquid like those falling out of these columns.



As I add nitric acid to the top of the columns, it slowly drains through the resin and strips out metals I don't want.  I can then use another acid, like hydrochloric acid or bromic acid, to take out the thorium and uranium.  If the columns weren't made of Teflon, the tension of the water would cause the drops to stick, and I would never get my sample!




Once I have collected the drops in Teflon beakers, I place them on a hotplate to evaporate most of the liquid.  All that remains is a tiny, tiny pinpoint of solid that contains my concentrated uranium or thorium.  These are the samples I will analyze on a mass spectrometer, an instrument that uses magnets to detect the mass (amount of stuff) in a sample.  Remember that every element on the periodic table has a different mass, and each element actually has different varieties, called isotopes, that differ slightly in mass because of the number of neutrons in their nucleus.  The magnets affect each mass differently, so when they hit the detector, the instrument knows what it is based on how it traveled through the magnetic field.

Mass spectrometers have revolutionized science, and in particular the earth sciences.  They tell me what kind of stuff I'm looking at, and based on the known physical properties of that stuff (like uranium), I can deduce much about the history of a material.  Geology is storytelling, and the clean lab offers an exquisite set of tools to read that story.

Wednesday, July 29, 2015

Red Sea Snorkeling

The Gulf of Aqaba has some of the best the best coral reefs in the world.  These reefs here have never been known to bleach (a process that deprives corals of their symbiotic algae and deprives reefs of their color).  These ultra healthy reefs are also in rather shallow water (less than 30 feet) making them great for snorkeling.   
Scientists in their natural habitat.  Alanna (left) and Ana (right) snorkeling at the IUI coral reef.

Over the past weekend a few of us went snorkeling twice, once during the day and again at night.  IUI has its own private beach where corals are protected.  This ensures the corals don't get trampled and can live happy lives.  A happy and healthy coral population also means a happy and healthy ecosystem with lots of fish. 
The most majestic of all sea creatures, the sea cucumber.  I saw this giant (~2 feet long) specimen leisurely strolling the ocean floor.
One fish especially abundant here are parrot fish.  These large fish come in a variety of colors and have a parrot-like beak.  They feed on corals, picking the coral polyps out of their calcium carbonate skeleton shells.

A parrot fish munching on some coral polyps, yum yum.
Of course many other fish inhabit these reefs, including picasso fish (named after their weirdly shaped heads), angel fish, reef grouper, and more.  Of course the corals themselves are rather impressive too, awash with many colors and shapes.

The healthy happy corals of the Gulf of Aqaba.
The scene had too many characters to sum up in a few photos.  So I took a video.


The next night after the sun went down we went snorkeling in the same area at night.  Many of the corals in this area fluoresce when an ultra violet light is shined on them, giving them a bright green glow.  This phenomena can only be seen at night with special ultra violet flashlights and filters which fit over our snorkel masks.
Modeling the yellow filters that fit over our snorkel masks for night snorkeling
We broke off into pairs.  Each pair got a regular flashlight for intermittent use when we needed to see where we were and an ultra violet flashlight to see the corals fluoresce.

A blurry photo of a brain coral fluorescing bright green.
I didn't have a filter for my camera like we did for our masks.  So the fluorescence is more difficult to see, but it is still apparent in the video below.  When the light passes over corals that fluoresce the color turns a sparkly green.

The lights also make it easy to spot snorkelers in the water a night.
Our group snorkeling at night with the ultra violet lights as seen from a nearby pier.

Monday, July 27, 2015

Red Sea Geology

Being a group of mostly geologists, we tend to notice the rocks around us.  Rocks are the pages of history we read to tell the Earth story; the story of the Gulf of Aqaba and the Red Sea is in the midst of an exciting chapter.

There are three dominant rock types in this region: granite, sandstone, and limestone.  You can see them in this picture from Timna when we visited.


The granites are the dark rocks on the left.  The sandstone and limestone beds are the lighter colored rocks on the right in the background.  The granites are about 630 million years old (about 1/7 the age of the earth).  They formed as magma slowly rose from the mantle and cooled slowly under the crust.  Over millions of years, that crust eroded away to expose them, and erosion continued on these crystalline blobs to produce flat land much like the topography of Australia.  This is called the peneplain.




Notice how the red line skims just the tops of these granite mountains in Jordan just across the gulf from our apartment.  These granite rocks are extensive and can be seen from space.




This picture of the Sinai Peninsula from Wikipedia shows the granites and sandstones.  Egypt is to the left of the Gulf of Suez (left fork) and Eilat is at the tip of the Gulf of Aqaba (right fork).  The dark rocks around the gulfs are the granites, and the lighter tan colors are the sandstones and limestones.

 The sandstones and limestones indicate a shallow sea and coastal environment.  These have been deposited over the last 500 million years or so.  When sea level rises, limestones are deposited, and when it falls, sands encroach over the limestones, eventually hardening to form the sandstone.  This produced the rock types seen here.





The story continues, however, with the start of East African Rift system about 25 million years ago.  Convection from the mantle is slowly pushing up on the eastern side of Africa.  As the heat spreads side ways, it pulls the continent in three directions and causes it to tear (called a triple junction).  This is the same process that rifted Pangaea apart 175 million years ago.  As the continent rifts, deep valleys open up and get flooded with seawater; this created the Gulf of Aden, the Red Sea, and, farther north, the Gulf of Aqaba.  The process is still continuing, and 200 million years in the future this region will be on the edge of an ocean as vast as the Atlantic.

Nature doesn't like holes, though, so it fills them.  Though the depression fills with seawater, the rocks themselves become unstable as the crust pulls apart.  They crack and sink downward to create large fault blocks.  Imagine a row of books slowly being pulled apart; those in the middle will slide to fill the space.

The sliding blocks create valleys and ridges (think of the Ridge and Valley province of Nevada).  In geology, these are called horsts (ridge) and grabens (valleys).  Younger rocks like the limestone and sandstone can slide downward and appear right beside old granites.  This results in a color banding from ridge to ridge.

Notice how the mountains behind the buildings on the left from from dark to light to dark to light.  The mountain peaks are split by these faults.  The process is still going on today.  About a week before we arrived, a relatively small 5.0 earthquake occurred as a block slide downward.  This will continue to happen until the coasts move far enough away from the ridge to become stable many millions of years in the future.