The Earth Story

Marie Tharp and the Mid-Atlantic Ridge

The ocean floor has always been a mysterious place and in the 1950’s it was even more so; most believed it was simply a flat, boring plain. After World War II, many feared the next warfront would be underwater, so the quest to gather more information about the ocean floor was in full force, which proved to be good for science.

Marie Tharp was working at the Lamont Geological Observatory when the funding for ocean research started pouring in. Many of her colleagues would go out to sea and come back with mounds of sonar data that could be used to determine the depth of the ocean floor. Back at the lab, Marie began piecing together the numbers and using them to make a map of the ocean floor.

Marie, and her colleague Bruce Heezen, began to notice something interesting about the map (which she made by hand, by the way)—the ocean floor was not flat. In fact, there were mountains! Underwater! Most notably, these mountains formed a very long chain, one that went right down the middle of the Atlantic Ocean. Marie thought it was a volcanic rift center, an idea that was initially dismissed as “girl talk”.

Marie and Bruce (who came around to the idea that it was a volcanic rift center) published their first map in 1957. At this time, most people still did not like the idea of a mid-ocean ridge because it was too closely linked with continental drift, which was considered geological nonsense at the time. A few years later, Harry Hess would use the Mid-Atlantic Ridge to support his theory of seafloor spreading, which ultimately led to the unifying theory of plate tectonics.

Marie devoted much of her life to mapping; she and Bruce released a map of the entire ocean floor in 1977. Our modern understanding of Earth processes and plate tectonics would not be possible without these maps. The discovery of mid-ocean ridges was a crucial piece to the puzzle of how continents move and ultimately why Earth works. So thank you Marie!

-CM

For more information: http://bit.ly/1BfCjWE http://huff.to/18oityd A brief autobiography: http://bit.ly/1mEqFR7 This book:http://amzn.to/1wMccZ0

Photo (Marie with Bruce Heezen) credit: Marie Tharp Maps http://bit.ly/1NqP5YX

V-Shaped Ridges

This image shows the bathymetry of the ocean floor just south of Iceland (reflected through the gravity), an area with a remarkable feature. See how there are linear features elevated above the surrounding ocean floor that open to the North? These are known as the V-shaped ridges and they demonstrate a remarkable property of the Icelandic plume.

Iceland is a unique spot on earth, a combination of a mantle plume and a mid-ocean ridge. The mantle plume carries hot material in the mantle up from deep, causing Iceland to rise above the ocean floor as a huge island. The mid-ocean ridge south of Iceland shows some influence of this plume, changing in composition and rising higher above the ocean floor than ridges elsewhere in the world.

The V-shaped ridges are formed at the mid-Atlantic spreading center. They’re elevated because they’re thicker, so they’re probably produced by melting of extra- hot mantle, like Iceland but not to the same extreme.

The real interesting feature from a geophysical perspective is the shape. The mid-Atlantic ridge keeps spreading at a constant rate regardless of what is happening along this ridge, so to produce a V-shape, a blob of mantle that produces extra melt has to actually migrate away from Iceland.

To make this ridge, a blob of extra hot mantle rises up south of Iceland and then flows away, being sampled along the ridge as it moves. This pattern of alternating ridges and valleys therefore tells us that whatever it is that drives volcanism in Iceland…it actually occurs in pulses!

A pulse of mantle that melts extra rises up beneath Iceland and migrates away down the Mid Atlantic ridge. The ridge pushes the rocks apart, making a V-shape out of that ridge, while another pulse forms near Iceland and begins moving its way to the south.

-JBB

Image credit: http://www.nature.com/nature/journal/v411/n6838/images/411681aa.2.jpg

Read more: http://onlinelibrary.wiley.com/doi/10.1029/2002GC000361/abstract

Pillow lavas

Every so often on the planet Earth, the weirdness of plate tectonics winds up creating a situation where part of the ocean floor is actually thrust up onto the continent. Often it’s thought this happens in settings related to subduction, where a tiny bit of ocean crust is formed as a continent is pulled apart, but then that new ocean crust is thrust back onto the continent when the basin closes.

This setup is thought to be the origin of the Oman Ophiolite, also known as the Samail Ophiolite, one of (if not the) best exposed ophiolites on Earth. In Oman, much of the stratigraphy of the ocean crust is preserved and available at the Earth’s surface. An enterprising geologist in the desert can literally walk across units that once ran from the ocean floor to the upper mantle.

In this shot, a geologist is standing by pillow basalts. Much of the world’s ocean crust is formed by eruptions at mid-ocean ridges. When lava comes up at a mid-ocean ridge, it interacts with the water at the edge and freezes, but it keeps expanding and flowing outwards, breaking apart the crust and forming what are effectively lava blobs that we call pillows, because they have a pillow-like shape. In this shot, you can see pillows exposed in cross-section; they have rims near their edges where the lava cooled more rapidly thanks to the surrounding seawater, and cores that look a little different because they cooled a little more slowly. Every blob-shaped area of rock in this image is a pillow lava.

This pile of pillow basalts, tens of meters high, is a tiny slice of what the Earth’s igneous ocean crust looks like. Person for scale.

-JBB

Image credit: Anita Di Chiara (distributed via imaggeo.egu.eu) https://imaggeo.egu.eu/view/13270/

A nice 6 minute summary of the basics of plate tectonics, the method underlying the creation and cycling of earth’s crust.

Dust plume over Earth's youngest sea.

The Red sea, an arm of the Indian Ocean, is the youngest sea on Earth. A spreading ridge started pushing Africa and Arabia apart, and has spread down Africa as the continental rifts. Whether this will end up with a splitting of the entire continent, or the african rift will turn into a failed rift graben (called an aulacogen, consisting of downfaulted blocks with old volcanic rocks and lake sediments within) remains unknown.

With a length of over 2,000 Km, and a width of 355, the sea started to open in the Eocene about 30 million years ago, speeding up in the Oligocene. Hydrothermal vents are currently forming metal sulphide deposits in varied areas of its floor. In this image, taken from the ISS, a dust plume is being carried by winds from Africa towards Asia, bringing eroded sediment to rejoin their once-neighbours on the other side of this narrow budding ocean. The Nile river is visible in the upper left of the image.

Loz

Image credit: NASA http://earthobservatory.nasa.gov/IOTD/view.php?id=81566&src=fb

Structure of the slowest spreading center

Earth’s surface is a 3-D puzzle, broken into discrete plates that wander their way around the surface. Plates typically don’t move entirely in a straight line relative to each other – instead they pivot around some point, moving in arcs across the sphere. Because of this motion on a sphere, a spreading center will move faster in some areas than others.

You can test this yourself with a simple demonstration. Put the palms of your hands together with your fingers touching. Now spread the palms of your hands apart, keeping your fingertips touching. Your hands have opened into a V-shape, right? Now note how far each part traveled – the palms of your hands moved much, much farther than your fingers did because they are farther from the pivot point.

There are only a handful of places on Earth where mid-ocean ridges get close to these pivot points and drastically slow down. One of them, the Gakkel Ridge, is in mostly hidden beneath sea ice in the Arctic Ocean. North of Iceland, the Mid-Atlantic ridge jumps to the side on a transform fault and continues heading towards Siberia as a very slow moving spreading center called the Gakkel Ridge. While the fastest ridge on Earth spreads at about 7.5 cm per year, at the Siberian side the Gakkel Ridge spreads at about 0.5 cm per year – slower than many faults on continents.

At a normal mid-ocean ridge, hot mantle rises upward to fill in the gap created between the spreading plates. Since it is upwelling and decompressing, it melts as it moves up and those melts create a pile of basaltic crust about 10 kilometers thick that makes up the ocean floor. However, at a slowly spreading ridge things are different – the mantle isn’t rising up fast enough to generate much magma.

Instead, the plate is moving so slowly that in places there isn’t enough heat to keep the crust warm. In those spots, the entire crust and even the mantle could cool down, limiting volcanism in those areas.

The Gakkel ridge is broken into segments, some of which generate magma and some of which don't. Previous dredges at this ridge have found mantle rocks exposed at the surface, showing that there are spots on the ridge that aren’t even covered by lava at all. Newly-published seismic work now shows the structure beneath these sections of the ridge.

Two authors from the Helmholtz Centre for Polar and Marine Research used seismic tools to understand the structure beneath this ridge. They measured the location of Earthquakes beneath the ridge to constrain the properties of the rocks.

Normally beneath a mid-ocean ridge there will be earthquakes in the upper, cold crust where the rocks are split apart, but deeper in the ridge the rocks are hot and don’t fracture easily. It turns out the Gakkel Ridge has almost the opposite pattern.

At shallow depths beneath the ridge there are almost no earthquakes in the areas that aren’t producing magma today. The rocks must be cold since they’re so close to the surface, so they must be lacking earthquakes for a different reason from normal ridges. Instead of being warm, these rocks are likely not producing earthquakes because the rocks themselves are weak. When mantle rocks are exposed to water, they react to form serpentine minerals and those phases are very weak and flow easily. The lack of earthquakes in the upper 10 kilometers at the Gakkel Ridge segments therefore argues that the entire layer has interacted with seawater and been serpentinized.

Below that depth, from about 10 to 35 kilometers deep, the scientists found many clusters of earthquakes. Beneath a normal ridge, this depth is typically too hot to produce many quakes, so beneath the Gakkel Ridge this area must be much colder. Beneath that depth, earthquakes disappear, showing that is the level hot mantle is reached.

By mapping out earthquakes beneath this ridge, the scientists learned about the structure of some of the rarest ocean crust on Earth. Interaction between fluids and rocks releases elements that can change the chemistry of the ocean and even could supply fuel for life, so discovering a thick serpentine layer beneath the Gakkel Ridge tells us about how the ocean crust reacts with water and illustrates part of the history of the planet itself.

-JBB

Image credit: NOAA http://bit.ly/29T2wUa

Original paper: http://go.nature.com/29yJNv3

Overlapping spreading centers

This photo shows bathymetry of the Pacific Ocean Floor in an area of the East Pacific Rise, the spreading center between the Pacific Plate and the Cocos Plate. Several features stand out as high elevation spots; off to the northeast you can see several seamounts, formed at the ocean ridge, that are notably high. You can also make out a pattern of ridges and valleys that roughly run parallel to the ridge at the center – these can be used to show which way the plates are moving. The Cocos plate is moving towards the upper right corner, the Pacific Plate is moving to the lower left.

In the center of this image, represented by the high ground, you can find the actual East Pacific Rise. Along this ridge, molten rock from melting the mantle is rising up and growing the oceanic plates. But now I want to highlight one specific feature of the ridge in this area. Start at the top left corner and follow the ridge – that segment of the ridge actually ends in the middle of the frame. Now, start at the lower right corner and follow the ridge – that segment of the ridge also ends. Right in the middle of this frame, there is a spot with ridges on both sides.

Spots like this one are complicated areas in plate tectonics. We draw maps where mid-ocean ridges are sketched as lines that offset only by large-scale transform faults. The point at the center of this frame is a complication to that drawing – it is called an overlapping spreading center as there are two spreading centers in the same place.

These features are common on Earth; there are literally hundreds of them along the mid ocean ridges. The ridge itself is broken and offset a tiny bit for some reason at that point. Over time, these overlapping spreading centers are thought to migrate along the ridge axis; they’re generated at one transform fault and move towards the next edge as the plate grows. One of those two ridges is growing while the other one is shutting down right next to it.

Exactly what causes these small-scale features on the ocean floor is poorly understood. If ocean plates are rigid, there’s no obvious reason for a ridge to break into small segments like this. Previously geologists suggested these overlaps form in areas where magma supply changes; a decrease followed by an increase could cause the ridge to jump to a slightly different spot. However, new research suggests these offsets may form instead due to pull in the mantle.

The main force that pulls oceanic slabs is their own weight. When an oceanic plate sinks into the mantle at a subduction zone, it falls all the way through the mantle and drags the plate at the surface with it. The mantle beneath a plate is sort of like a putty, soft enough to allow the plate to flow on top of it but still with some strength of its own.

If that mantle is flowing in a different direction from the plate, the rigid plate might feel it and be tugged side to side a little bit. These just-published results from scientists at the University of Oregon argue that is how these form – the mantle beneath is flowing in a different direction and that flow slowly tweaks the oceanic plate to move in a different direction.

To measure the flow in the mantle, they used seismic measurements. Most minerals in the mantle are anisotropic – seismic waves move faster through them in one direction than in others. If all the grains are arranged randomly then seismic waves will move at the same speed regardless of which direction they move. But, if the grains are flowing, they will arrange themselves so that there is a fast direction and a slow direction – this is called “seismic anisotropy”.

The researchers investigated seismic data from along several ridges, including the Juan de Fuca ridge, and found seismic anisotropy that was at an angle to the mid-ocean ridge, meaning the plate and the mantle are flowing in different directions. Part of the oceanic plate gets dragged forward and part is dragged backwards by the flowing mantle below, twisting the plate slightly. That sort of twisting is exactly what could give rise to spreading center offsets like this one, and over time it could slowly change the path taken by plates at the surface.

The segments of ridges investigated in this work are generating offset spreading centers in the direction expected if the mantle flow below is twisting the plate at the surface. However, this study just focuses on 3 spreading centers where data was available. To test it further, scientists will have to go to other spreading centers around the world and find the same relationship between mantle flow and plate motion.

-JBB

Image credit: Nature news and views http://go.nature.com/29fFMO7

Original paper: http://go.nature.com/2962ffD

If the first frame of this video, saying “Why Iceland” and answering it at the same time, doesn’t get you to click I don’t know what to do.

Birth of the Atlantic

This is a gorgeous computer rendering of the opening of the Atlantic Ocean and the breakup of the Supercontinent Pangaea.

During the Triassic and Jurassic, North America began rifting from the part of Gondwana (today Africa) that it had collided with to build the Appalachian Mountains and later during the Jurassic, the huge block of South America and Africa that had been linked together for hundreds of millions of years also separated.

The breakup of a Supercontinent can have many causes. Plates far away can be pulled down into the mantle and a rigid plate could transmit stress to weak points far away, causing the plate to pull apart. Alternatively, something could wedge its way in-between the plates and force them apart; both of these breakups occur at the same time as huge outpourings of volcanic lava, maybe suggesting that a hot plume of mantle material rose up and pushed them apart. The arrows that appear and change on each plate show how the plate motion directions change as these different forces interact. The longer the arrow = the faster the plate is moving.

The plate motions of the past 200 million years or so are known extremely well because of magnetic anomalies. When new seafloor is created at a mid-ocean ridge, that seafloor records the direction of the Earth’s magnetic field at the time. As the rocks move away from the ridge, they preserve a record of where on the planet’s surface they formed. By mapping out magnetic anomalies across the planet’s ocean floors, we find a record of how the oceanic plates move.

That record only goes back about 200 million years because that’s the oldest oceanic crust on Earth. Almost all the oceanic crust older than that age has cooled off so much and become so dense that it has readily subducted, heading down into the mantle to start the cycle again. The age contours in this plot let you see how that age progression happens; new crust formed at mid-ocean ridges and then older crust vanishing beneath subduction zones like those on the western side of North and South America.

-JBB

Video Credit: NOAA http://sos.noaa.gov/Datasets/dataset.php?id=569

Loki’s Castle

“I was a king, the rightful king of Asgard! Betrayed!”

This week, moviegoers are again visiting the Marvel cinematic universe and being greeted by the team brought together when a villain brought destruction to midtown Manhattan. That villain’s name: Loki.

Of course, Loki isn’t just a character in the Marvel cinematic universe, he’s also a Norse God, and in that capacity he has loaned his name to this marvelous structure off the coast of Norway; Loki’s Castle.

In 2008, researchers on a dive to a section of the mid-Atlantic ridge between Norway and Greenland stumbled upon a spectacular find; a spectacular hydrothermal field, filled with a great number of structures like the ones you see in this image known as black smokers.

At the mid-ocean ridges, plates are pulling apart, creating space that is filled by hot mantle that melts as it rises. That magma forms a thick sequence of igneous rocks (typically 5 to 20 kilometers) and makes up the ocean floor and the crust of oceanic plates.

A 5 kilometer thick pile of lava has a lot of heat in it that has to be released into the oceans for the plate to cool down. Much of that cooling happens via hydrothermal circulation; water enters in through cracks in the crust, circulates to where the rocks are hot, is super-heated, and then ejected out onto the ocean floor in hydrothermal areas like this one.

More than water comes up these vents. Super-heated water is able to dissolve minerals in the rocks, and it carries those minerals and elements up to the ocean floor. When the hot water hits the ocean, it is immediately cooled and the dissolved minerals precipitate, forming tall black chimneys like the black smoker you see here.

Areas like this one teem with life. Life is able to use some of the energy from the heat pouring out of the rocks and it is able to use the chemicals dissolved in the water as an energy source as well. Last summer, it was reported that already 20 new species had been catalogued from this site, and work is ongoing to identify others. The researchers have proposed making Loki’s Castle into a national park, which to my knowledge would be the first national park located on a submarine mid-ocean ridge.

On top of all that, the combination of hot water, minerals, and chemistry makes settings like Loki’s Castle one of the prime candidates for where life could actually have begun on Earth (or even other planets).

So…there’s a decent chance we’re all descended from a creature born in an ancient version of Loki’s Castle.

Kneel before your father!

-JBB

Image credit(s): Center for Geobiology, University of Bergen http://www.livescience.com/38705-norway-deep-sea-vents-protections.html Marvel/Disney: http://blogs.denverpost.com/nerd/2013/08/06/avengers-2-loki-not-in-age-of-ultron/842/

Press release: http://www.sciencedaily.com/releases/2013/08/130802080240.htm

Marie Tharp and the Mid-Atlantic Ridge

In honor of International Women’s Day and the beginning of Women’s History Month, we thought some of our favorite female geologists deserved a shout out. One of my personal favorites is this girl, Marie Tharp, who did something very important for our modern understanding of geology—she discovered the Mid-Atlantic Ridge.<!-- more --.

The ocean floor has always been a mysterious place and in the 1950’s it was even more so; most believed it was simply a flat, boring plain. After World War II, many feared the next warfront would be underwater, so the quest to gather more information about the ocean floor was in full force, which proved to be good for science.

Marie was working at the Lamont Geological Observatory when the funding for ocean research started pouring in. Many of her colleagues would go out to sea and come back with mounds of sonar data that could be used to determine the depth of the ocean floor. Back at the lab, Marie began piecing together the numbers and using them to make a map of the ocean floor.

Marie, and her colleague Bruce Heezen, began to notice something interesting about the map (which she made by hand, by the way)—the ocean floor was not flat. In fact, there were mountains! Underwater! Most notably, these mountains formed a very long chain, one that went right down the middle of the Atlantic Ocean. Marie thought it was a volcanic rift center, an idea that was initially dismissed as “girl talk”.

Marie and Bruce (who came around to the idea that it was a volcanic rift center) published their first map in 1957. At this time, most people still did not like the idea of a mid-ocean ridge because it was too closely linked with continental drift, which was considered geological nonsense at the time. A few years later, Harry Hess would use the Mid-Atlantic Ridge to support his theory of seafloor spreading, which ultimately led to the unifying theory of plate tectonics.

Marie devoted much of her life to mapping; she and Bruce released a map of the entire ocean floor in 1977. Our modern understanding of Earth processes and plate tectonics would not be possible without these maps. The discovery of mid-ocean ridges was a crucial piece to the puzzle of how continents move and ultimately why Earth works. So thank you Marie!

-CM

For more information: http://bit.ly/1BfCjWE http://huff.to/18oityd A brief autobiography: http://bit.ly/1mEqFR7 This book:http://amzn.to/1wMccZ0

Photo (Marie with Bruce Heezen) credit: Marie Tharp Maps http://bit.ly/1NqP5YX

Fracture Zone quake

On Friday, a large earthquake occurred in a geologically interesting area of the mid-Atlantic ridge. The mid-ocean ridge system is a gigantic chain of mountains that stretches around the world on the ocean floor at the boundaries where plates are spreading apart.

The mid-ocean ridges aren’t just straight lines; they twist from side to side and are broken into segments that lock in the original shape of the plates. The oceanic rift zones themselves are dominated by normal faults, the kind that commonly occurs when two plates pull apart. To step sideways, a spreading center breaks into two segments with a strike-slip fault in-between, the type of fault that forms when one plate grinds past another.

The Charlie Gibbs fracture zone is an oceanic transform fault, a strike-slip fault on the ocean floor. On Friday, that fault broke, producing a magnitude 7 earthquake.

Because the rocks just were sliding past each other, side to side, there was no tsunami generated and since the quake occurred far out to sea there was no major damage, just a geologically interesting place for a strong earthquake. This fracture zone has produced several earthquakes of this size in the past 60+ years since humans have been actively monitoring seismic signals.

-JBB

Image credit: USGS http://on.doi.gov/1KTMeFx

Decompression melting

One of the most interesting facts about how magma is generated around the solar system is that magma formation isn’t about heat; its mostly about pressure.

People living at a constant pressure of 1 atmosphere just aren’t used to this. The most we see is slight variations in water boiling point sdue to small changes in elevation and atmospheric pressure, but that’s really not how it works inside Earth.

Inside a giant, solid, piece of rock, changes in pressure become hugely important. The majority of igneous rocks around the earth are generated at mid-ocean ridges and the dominant way these rocks melt is from reduction in pressure; hot rocks in the mantle at are great enough pressure that they are solid no matter the temperature, but if they rise up and the pressure drops, they start to melt from decompression.

That reality links to a hugely important story in recent geologic history. 20,000 years ago, there were huge ice caps covering continents and mountain ranges in North America, Europe, and Asia. As a consequence, the oceans were lower, reducing the pressure on mid-ocean ridges and increasing the pressure on continents. About 12,000 years ago, those glaciers melted, releasing all that mass back to the ocean. That water put pressure back on the rocks in the ocean and dropped pressure on land where the glaciers had melted away.

It takes a few thousand years for magma to migrate from deep in the earth to the surface, so the pulse didn’t hit immediately, but the result of the end of glaciers was a pulse of volcanism on land and a temporary slowdown of volcanism in the ocean along mid-ocean ridges from the increase in pressure.

This increase in pressure from melting glaciers has happened at least a half-dozen times in the last million years and may have gone on longer. The volume of glaciers varies based on the earth’s orbital cycles, altered by the amount of sunlight hitting areas like Canada where glaciers become stable during times of low solar flux.

A paper just out from scientists at the University of Oxford and Harvard University showed images like this from the Southwest Indian Ridge, a slow-moving section of the mid-ocean ridges. See how there are high part and low parts? Those high parts and low parts turn out to have the same periodicity as the Earth’s climate cycles.

Every 100,000 years, glaciers expand and contract, and during that there are pulses on 20,000 and 40,000-year timescales as a result of changes in the Earth’s orbit around the sun. Those changes in glacier volume translate to changes in pressure from the ice sheets on the continents and changes in the volume of the ocean – changes in the pressure in the ocean.

It takes about 1000 years for a change in ocean volume to be reflected in changes in magma production, but even small changes in ocean volume will change the pressure on magma generation regions. Increase the pressure, generate less magma, and wind up with thinner crust.

These regions on the ocean floor represent pulses of high and low of magma production and the fact that they line up with the recent climate cycles in this area is impressive – the changing ocean volumes lead to changing pressures and clearly produce ridges at times of high magma production and valleys when magma supply is low. This signal is obvious, not swamped out by any other process happening in the ocean.

If volcanoes on land also become more active, the extra ash can also block out sunlight, cooling the Earth. In other words, the melting of glaciers can, over a couple thousand years, produce a result that cools the Earth and feeds back into global cooling. In an era when climate is changing a consequence of natural processes, this increase in ash and aerosols 1000+ years after the breakup of an ice sheet could feed the growth of new ice sheets and start a cooling process.

For humanity, with the current warming trend driven by burning of fossil fuels, the end result could well be an enormous pulse of volcanic eruptions in about 1000 years or so. If humans are still left then, even though those volcanoes could counteract a warming trend….a whole lot of volcanic eruptions around the world is generally a bad thing since volcanoes produce disasters on their own.

-JBB

Image credit and original paper: http://bit.ly/1yS7TXa http://bit.ly/1zHlOSr http://bit.ly/16sKHqo

The Most Isolated Island in the World – Bouvet Island  Go to Iceland, turn south on the Mid-Atlantic Ridge and follow it all the way to the triple junction where the ridge intersects the Antarctic Plate, and there you will find… an island. At 2260 kilometers from the nearest inhabited island (Tristan de Cunha with a population of 271, if this counts), smack dab between Africa, South America and Antarctica, Bouvet island is not a very big island, less than fifty square kilometers in size with nearly all of it covered by a glacier, but is considered as the most isolated land mass on earth. Nevertheless, it turns out to be – an island of mystery! Discovered in 1739 by the French (hence the name), claimed by the British in 1825, and annexed by Norway in 1928, there has never been a war or disagreement about the sovereignty of the island – apparently no one loves it enough to argue over it, and it is, today, a nature reserve (apparently seals and penguins do like the place). The Norwegians take responsibility for it, with the island’s administration managed by their Polar Department of the Ministry of Justice and the Oslo Police. Since the island is uninhabited, the police have little to do there one supposes. Perhaps in hopes that someday someone would like to take up residence, an internet domain has been set up under its name (.bv), but as yet no takers. The average high temperature on Bouvet Island is just above 1C, and average low temperature is -2.3C – we know this because there is an automated weather station on this desolate locale. Nor is the island forgotten by the seismographs of the USGS who keep track of all earthquakes in the world, even those in Norwegian territories in the South Atlantic, and spotted a 5R earthquake near there (well, “near” as distances go for the most isolated spot in the world, about 348km west of the island) in 2009. Since geologists never forget about any island, no matter how great or how small, there are geologic papers on Bouvet Island that describe its volcanic composition (sitting on the Mid-Atlantic Ridge, not surprisingly these include Mid-Atlantic Ridge Basalts – “MORB”.) The island is as close to the site of a plate tectonic triple-junction as can be: it’s just on the edge of the African Plate next to the South American plate border (the Mid-Atlantic Ridge marking this), intersecting with the Antarctic plate. The island’s volcano has been hypothesized to be a “hot spot” where material is coming directly from the mantle. This tectonic environment is “way cool” for a geologist, and perhaps were there not so many glaciers occluding the island, some poor lost PhD student would have a great time in the frigid field. Some mysteries surround the island: an abandoned boat stocked with supplies (but no passengers) was found there in 1964; in 1979, a US satellite saw an extremely bright light flash from the uninhabited area near the island that is speculated to have been a nuclear bomb test by the Israelis and South Africa (come on, conspiracy theorists! You can do better than this!); AND there’s a disappearing island nearby!  Unlike Sandy Island in the Pacific that probably never existed in the first place (as recently reported by The Earth Story), Thomson Island was “discovered” to the northeast of Bouvet Island and seemed to exist in 1825 and 1893 (including very convincing sketches), but hasn’t been sighted since at least 1927. Possibly Thomson Island, also theoretically on the Mid-Atlantic ridge, could have been destroyed in an eruption or some caldera collapse, but in the 1960’s sonar failed to locate any sort of submerged shoal – since the original coordinates of the island’s position were done with the cutting-edge technology of 1825, possibly the sonar was looking in the wrong place.  Since the Norwegians haven’t yet sent out the Oslo Police to figure out who may have stolen the island, all theories are still open.  Annie R. Photo credit: We delightfully note that Google Panoramio has even made it to the most desolate island on earth and this photo is by: Franco Cain on Google Panoramio http://wikitravel.org/en/Bouvet_Island https://www.cia.gov/library/publications/the-world-factbook/geos/bv.html http://www.atlasobscura.com/places/bouvet-island http://www.antarctic.ac.uk/documents/bas_bulletins/bulletin13_06.pdf http://on.fb.me/1Ceod9v http://link.springer.com/article/10.1007%2FBF00451868?LI=true