Stories tagged Earth Structure and Processes
National Fossil Day: A great time to dig fossils (both literally and figuratively).Courtesy Mark RyanNext month, the National Park Service once again teams with the American Geological Institute and other partners to celebrate the third annual National Fossil Day.
The mission of NFD is to “promote public awareness of fossils as well as to foster a greater appreciation of their scientific and educational value.”
This year the official day falls on October 17, but celebrations take place at various locations around the country over several days. Here at the Science Museum of Minnesota, the day will be celebrated on Saturday, October 20, 1pm-4pm throughout the museum. You can see what events are happening in your own area here.
Besides going out and hunting for fossils, one of my favorite NFD activities is the National Fossil Day Art & Photography Contest. As in previous years, the competition is open to anyone across several age groups. This year’s theme is “Careers in Paleontology”. A panel of NFD partners and paleontologists will select the winning entries. I’ve already sent in my submission but you have until October 5th (postmark deadline) to enter your own masterpiece.
National Fossil Day is usually observed in conjunction with Earth Science Week and this year is no different. EWS occurs October 14-20, and this year’s theme is Discovering Careers in the Earth Sciences.
Tags : ![Celebration of Agates: fans and aficionados of the gemstone packed the gymnasium at Hopkins High School in Minnetonka, Minnesota for "A Celebration of Agates".](/sites/default/files/images/agate_show125.jpg "Celebration of Agates: fans and aficionados of the gemstone packed the gymnasium at Hopkins High School in Minnetonka, Minnesota for "A Celebration of Agates".")
Celebration of Agates: fans and aficionados of the gemstone packed the gymnasium at Hopkins High School in Minnetonka, Minnesota for "A Celebration of Agates".Courtesy Mark RyanA special group of rock hounds gathered over the weekend in the Twin Cities to celebrate and give praise to agates, those special gemstones found in just about every country of the world. “A Celebration of Agates” was held July 26-29, 2012 at the Lindbergh Center at Hopkins High School in Minnetonka, MN.
Agates on display: A young visitor admires a collection of Montana agates.Courtesy Mark RyanThe weekend event was hosted by the Minnesota Mineral Club and included presentations, book signings, banquets, plenty of vendors, and lots of agates – piles of them, on tables, in buckets, inside display cases, all there for the public to enjoy.
Each year at the Minnesota State Fair, I man a booth for the Geological Society of Minnesota. It’s great talking geology with visitors, answering their rock and geology questions. But by far the most frequent questions and discussions are about agates - specifically, those found in the Lake Superior region. It’s not surprising that the Lake Superior agate is Minnesota's state gem.
A pile of Lake Superior agates: Minnesota's state gem.Courtesy Mark RyanThese beautiful gemstones formed inside the empty spaces (vesicles) created by gas bubbles trapped in lava flows that poured out during the Mid-continental Rift (MCR) episode about a billion years ago and cooled into fine-grained basalts. Later, when the basalts were buried deep under sediments, ground water or hydrothermal activity flowing through the sequence deposited minerals (mainly silicon dioxide) inside the empty spaces layer by layer - and from the inside out - forming amygdules. Trace minerals and impurities can add color to each layer, creating bands of different color. In the Lake Superior area, the rocks became exposed again, and the basalts began to weather leaving the harder amygdules to fall out. Glaciers transported agates from the Lake Superior region and deposited them with tons of other rocks forming gravel pits to the south of the lake. Some of the best Lake Superior agates can be found around the Twin Cities.
A table of Kentucky agatesCourtesy Mark RyanPersonally, I never got into collecting them, I’ve always been mostly into fossils, but I have to admit, some of those agates I saw at the show were stunningly beautiful pieces of natural art. There’s something very attractive about a collection of Lake Superior agates covering a tabletop or laid out inside a display case. But Minnesota’s state rock wasn’t the only agate on display. Participants from many states and several countries including India, Australia, Germany, and South America brought their collections and knowledge to share with other agate lovers.
Geodes for the picking: Coconut geodes from the La Choyas Mine in Chihuahua, Mexico.Courtesy Mark RyanI usually don’t buy rocks, fossils or minerals – I like to find my own – but after I watched one vendor use some sort of strange bolt-cutting tool to break open several large geodes visitors had selected, I had to try my own hand at it.
Buckets of geodes lined a nearby table. The largest were as big as a softball but picked out a modest, three-inch diameter "Mexican Coconut” mined in Chihuahua, Mexico. 
Splitting my geode: a special cutting tool puts great pressure on my selected geode.Courtesy Mark RyanThese geodes formed in a similar manner as most agates: a hollow space left by gas bubbles in a cooling lava flow allowed for minerals to line the interior and crystals to grow as groundwater flows through it. Sometimes agate (chalcedony i.e. silicon dioxide) forms inside, other times it can be any number of iron-oxides, silicates (quartz), or calcite. The “Coconut” geodes formed in a 44 million year old ash-flow tuff that over time eroded into whitish clay. The geodes are mined from the clay 200 feet below the surface. Geode is a general term for a rock with a hollow space inside. Sometimes geodes can contain agate material such as chalcedony or jasper, and sometimes agates can be considered geodes (if they have a hollow space), but the two terms aren’t always interchangeable.
According to the very helpful vendor, the trick to picking the most primo geode was to find one the feels lighter than others of comparable size. It would logically follow that it has a larger hollow space and therefore possibly more crystal growth inside.
Split geode: blue quartz and geothite crystals line the interior cavity.Courtesy Mark RyanSo, I picked out a good one, and the vendor took it and tightened what looked like a large bike chain around the stone, then applied pressure on the cutter handle. After a sharp crack of sound, the geode broke open and fell into his hand in two equal halves. Inside each was a beautiful blue, milky lining of quartz dotted with dark, rod-like crystals of goethite, a hydrated iron oxide.
The event also featured a black-light tent for viewing florescent minerals, videos about agates, hourly drawings, on-going silent auctions, geological tools and lapidary supplies for sale, a ton of agates, and a whole flock of agate-lovers more than happy to show their favorite finds to the droves of rock hounds who came to see them.
![Dazzling Lake Superior agates: these three superior beauties are appropriately featured on the cover of the book "Agates of Lake Superior".](/sites/default/files/images/agates_of_lake_superior.jpg "Dazzling Lake Superior agates: these three superior beauties are appropriately featured on the cover of the book "Agates of Lake Superior".")
Dazzling Lake Superior agates: these three superior beauties are appropriately featured on the cover of the book "Agates of Lake Superior".Courtesy Mark RyanI think my favorites were the three stunning grapefruit-sized agates that grace the cover of a recent book titled Agates of Lake Superior written by Dan and Bob Lynch from Two Harbors, Minnesota. They had all three beauties on display. Two were found in the Two Harbors area, and the other in a gravel pit near Forest Lake, MN.
The Soudan Underground Mine entrance: Shaft #8 headframe (center) once transported miners to various levels up and down the mine shaft. Today it delivers park visitors to Level 27 for tours of the iron ore mine. It also transports scientists to and from the High Energy Physics Lab on the same level.Courtesy Mark Ryan
The long spell of unusually hot weather (see Thor's post) may have you looking for some relief, so let me suggest you head for northern Minnesota. No, I’m not talking about Duluth or the North Shore of Lake Superior (it’s been hot there, too), but way up north to the Soudan Underground Mine State Park on the southeast shore of Lake Vermilion (Map). The Soudan Mine is one of several underground mines that once operated in the Ely area, and was the oldest and deepest mine in Minnesota. It’s the perfect place to bring the whole family to learn about Minnesota’s iron mining past and descend a half mile into the earth where you can experience for yourself what it was like to work in an underground mine. An added perk during these steamy summer days is the fact temperature in the mine year-round is a cool 51°F.
In June, my brother Pat and I made one of our frequent geo-tours north, and this time our primary goal was to visit the Soudan mine. After some time exploring Manitou Falls near Superior, Wisconsin, and the eerily fog-shrouded Palisades on the North Shore, we made a beeline up to Ely where we spent the night. The next morning we drove the twenty miles west to Soudan, arriving just after 9am. As we neared our destination, the headframe of Shaft #8 could be seen looming above the ridge-line, making it fairly easy to find the park. Shaft #8 is the operational shaft that takes you underground.
The crushing house at Soudan: Iron ore from the mine was crushed here into seven-inch chunks before shipping.Courtesy Mark RyanThere are two tours into the mine available to the public: the High Energy Physics Lab tour and the Mine History tour. These are separate tours and can't be taken together, and since our time was somewhat limited, Pat and I opted for the history tour. It was slightly longer (about 90 minutes) , included some geology, and seemed like the way to go. So we bought our tickets and while waiting for the tour to start, we checked out the grounds and buildings where the implements and artifacts once used for mining can still be seen. These included the crushing house, the dry house, and drill shop. 
Engine house at Soudan: the equipment still operates the hoist that delivers visitors in and out of the mine shaft.Courtesy Mark RyanThe machinery in all these buildings stand idle today, but not so with the engine house. The equipment there still drives the cables and hoist that delivers visitors to and from the mine. Beneath the headframe, Pat sighted several bats fluttering up from the shaft. Three bat species inhabit the mine: the little brown, Eastern pipistrelle, and Northern myotis. But don’t worry, they weren’t any bother at all during the tour.
Across the road from the headframe is a deep, long gash in the ground overgrown with vegetation that was once one of the original open pit mines. Staring down into the hole, it’s not hard to imagine the difficulty the miners faced extracting ore from its steep walls. Pat and I didn’t have time to take the hiking trail far enough to see the much-photographed Soudan Iron Formation outcrop – something I regret - but we did see a couple other open pit mines on the property.
Minnesota's first iron ore mine: This open pit mine at Soudan produced the first iron ore shipped from Minnesota.Courtesy Mark RyanThe first iron ore mined in Minnesota was taken from an open pit in Soudan, and shipped by train to Two Harbors at Lake Superior in the early 1880s. The promise of gold had attracted a lot of prospectors to the Arrowhead Region of Minnesota, including George Stuntz, a Duluth civil engineer who established the Vermilion Trail into the area. But instead of gold, he found iron ore. The Vermilion Range, with its rich iron ore, would be the first of several major iron ranges discovered across northern Minnesota. In nearly 80 year of operation, Soudan produced nearly16 million tons of rich iron ore that were shipped across the Great Lakes to steel mills in the East or in later years, sent by train down to the steel mill in Duluth. (I worked at the US Steel mill in Duluth for a year. My first job was on the high-line tracks where iron ore and other steel-making materials were delivered by train to the open hearth furnaces. During lunch, I’d watch my co-workers tap the furnaces. When the molten steel was ready to go, alarms and sirens would sound as a small bomb was sent into the furnace that would blow out the plug, forcing the molten steel to pour out into giant multi-ton ladles. Very impressive and extremely noisy!).
At 10am sharp we gathered with other visitors for the tour. After a quick video explaining an overview of the mine and its history, everyone grabbed a hardhat and loaded into the shaft’s elevator or “man cage” as the miners called it. A dozen of us crammed into the cage for the ride down. It wasn't too bad but it bordered on stuffy, especially in the heat. Our tour guide, a very pleasant young woman, eagerly imparted her knowledge of the mine’s history and the safety issues involved with the tour. She informed us that back when the mine was operational eighteen miners usually wedged into the cage for each transport.
Generalized view of Soudan Mine c. 1898: the shaft extends down 27 levels parallel to the ore body.Courtesy Minnesota Geological SurveyThe ride down to Level 27 took under three minutes. The shaft is angled about 78 degrees so besides traveling half a mile underground we also moved 500 feet north of the headframe and underneath the nearby old open pit mine. During our rattling, rapid descent, our guide held her flashlight against the scuffed window so we could see something - the occasional reflection of dim light as we shot past levels - otherwise it would've been a pretty dark ride. Two levels (#12 and #22) were lighted because they’re still used to pump out the relatively little water seeping into the mine.
Riding through the drift: In the old days miners had to walk the 3/4 mile tunnel to the stope in the dark.Courtesy Mark RyanLevel 27, the deepest level in the shaft, was lighted, too, at least where the elevator stopped. The physics lab is located on the same level and we could see its entrance as we exited the elevator. We were joined by a couple more guides who herded us into small rail cars for the last leg of the trip, this time horizontally through a dimly-lit 3/4 mile passageway called a drift. The mineshaft and drift were dug out through Ely greenstone. As promised the temperature in the mine was a cool 51°F and a refreshing break from the surface heat. At least I thought so. Some folks were wearing sweatshirts or light jackets, but I was comfortable in just a t-shirt and shorts.
Level 27 stope: Our guide explains some of the rock formations found inside the mining chamber.Courtesy Mark RyanAt the end of the tunnel we detrained and were led up a metal spiral staircase (the miners used ladders) to reach the stope, a large, cavernous space carved into of the ore layer. Our guide pointed out some of the geological features including adjacent greenstone layers, mineral veins of copper, and of course, hematite. She explained how holes were drilled into the walls of the ore body, and explosives placed inside for blasting. After the controlled explosion, and before any miners were allowed in, a barman was sent in to knock down any loose rock from the ceiling. Barring was one of the higher paying jobs in the mine but probably the most dangerous.
The miners used the “cut and fill” method to mine the ore from the ceiling. Waste rock was let drop and used to create an ever-rising artificial floor that remained pretty much the same distance from the ceiling being mined. This eliminated waste rock disposal to the surface. The dense ore, which weighed as much as 325 pounds per cubic foot, was sent down chutes into granby cars on the level below them for transportation back to the skip that carried it up to the top. The granby cars and skip each held 6 tons of ore and miners were paid according to the amount of ore they sent up to the surface. There, the ore was dumped into larry cars and transported to the crusher house for crushing, then either loaded into waiting train cars or stockpiled for later shipping.
Soudan Iron Formation: This banded iron formation seen at Soudan Underground Mine State Park was deposited in a marine environment 2.7 billion years ago.Courtesy Jvstin via FlickrThe iron deposits found at Soudan precipitated out of an ancient sea during the Early Precambrian period about 2.7 billion years ago. The iron was deposited on pillow basalts extruded during earlier volcanic activity. Pillow basalts form when molten rock comes in contact with water. The iron, which also originated from volcanic activity, interbedded with deposits of mud and sand forming what’s called a banded iron formation or BIF. Unlike the large and extensive single bed of iron ore occurring in the Mesabi Range, the iron ore at Soudan was laid out in small lenses. More pillow basalt flowed atop the iron layers. Later, probably through hydrologic processes, the iron content was enriched and the entire sequence tightly folded and deformed by tectonic forces from regional mountain-building episodes (orogenies) and later baked by the underground upwelling of magma during intrusion of the Duluth Complex gabbro. The heat and pressure metamorphosed the sequence, transforming the basalt into Ely greenstone (shist). The entire sequence eventually ended up nearly vertical in an anticline with layers of hematite, jasper, and chert sandwiched between layers of greenstone (also known as chlorite).
Miners working the underground mine at Soudan often referred to it as the “The Cadillac of Mines”. Compared with other underground mines near Ely, it was relatively dry, the temperature was a comfortable 51 degrees year round, and fresh air permeated all the levels. But to show that it wasn’t all rosy, our guide demonstrated what it must have been like for the miners before electricity. The mine chamber was well lighted for us tourists but to give us an idea what the early miners experienced she extinguished all the lights and held a single burning candle near her face. It wasn’t very bright at all and kind of spooky.
Mining the stope: Mannequins fill the role miners once held in a Level 27 diorama.Courtesy Mark RyanLater, when electricity was put in, lighting improved, and power drills were used in the mining process. After a sufficient warning, our guide played for us a recording of the sound made by a single drill at work just to give us an idea of the noise level produced. The decibel level I remember from working in the steel mill was nothing compared to what the miners must have endured when several drills were going at once. It’s no wonder many of them suffered hearing loss after years working the mine.
As steelmaking processes were refined, the need for Soudan’s rich ore diminished. Using low-grade iron taconite became more economical for use with new oxygen-fed furnaces. Soudan shut down operations in 1962. The next year, after all the stockpiled ore had been shipped, US Steel Corporation gave the mine and an additional 1100 acres of land to the state of Minnesota for $1. The stipulation was that the site be used for educational purposes. Minnesota turned the site into a state park in 1965.
Mining artifacts in Soudan mine: mining equipment from the old days can still be seen in the mine.Courtesy Mark RyanI found the Soudan Underground Mine State Park well worth the trip. Where else can you travel a half-mile underground into 2.7 billion year-old rock formations and cool off at the same time? (The temperature at the bottom of the Grand Canyon is much hotter than at the top). Soudan's a great place to learn about Minnesota mining history, see area wildlife and check out some of the unique geology in the Lake Vermilion region that helped make Minnesota a leading iron ore producer.
Entry to the park is free and requires no state park sticker. The mine tours, however, require a fee. Pat and I paid $12 each. Kids are cheaper. The tours begin on the hour from 10am to 4pm daily. Tours for the High Energy Physics Lab occur only twice each day, the first at 10am and the second at 4pm. As I mentioned before, you can't combine tours so you have to pick either the historic one or the physics one. Mine tours are available from late May until the end of September. Follow this link for additional information.
On our way home, Pat and I agreed we'd come back sometime soon for the High Energy Physics Lab tour where physicists investigate things like the particle mass of neutrinos, and detect other dark matter particles. The lab is run by the University of Minnesota. However, I recently learned there’s a third mine tour available at Soudan, one offered only to organized groups. This one is more geology-focused and instead of riding the train through the 3/4 mile of Ely greenstone to the ore body, participants walk through the drift and are given a detailed lesson in geology along the way. I definitely have to join me up with one of those groups. Maybe next summer.
Did I mention it’s 51°F in the mine?
LINKS
Short video of Soudan Underground Mine tour
Minnesota mining history
More DNR Soudan info
Gigapan of Soudan Mine site
Soudan at Wikipedia
DNR Soudan Mine site
MN Conservation Volunteer article on Soudan Mine
Evolution timeline from 1882: This caricature of Darwin's theory appeared in the 1882 Punch Almanac. The recent evolution timeline created by Kyrk and Sezen is a bit of an improvement.Courtesy Public domain via Wikipedia This cool evolution timeline is really fascinating and fun to mess around with. I'm guessing Charles Darwin would agree it's a vast improvement over the one that appeared in Punch Almanac in1882 when he was still alive (see image at right). This new one was created by John Kyrk, a biology-trained artist in San Francisco in collaboration with Dr. Uzay Sezen, a plant biologist from the University of Georgia. The timeline is available in several languages and would be very useful in a classroom setting when studying evolution and paleontology.
The site is interactive and follows the evolution of our universe from the Big Bang to the present. You start it by clicking and sliding the red pyramid on the right. As you scroll across the timeline, various events in the history of the Universe, Solar System and ultimately, the Earth show up on the screen. All along, links also appear that either explain concepts or show examples of them. In the upper left hand corner is a menu linking you to several corollary Flash animations by Kyrk explaining cell biology and how RNA, DNA, cells, water, and other basic elements of life (including viruses) operate. Kyrk thinks animated illustrations are very useful in teaching and remembering ideas and concepts.
All the phases of Earth’s formation and development are covered in the evolution timeline, including the Late Heavy Bombardment, Snowball Earth, Cambrian Explosion, stromatolites, photosynthesis and iron formation. Once life begins to rise up, your computer screen will run amok with Earth’s diverse species populations from the one-celled animals, trilobites and fish to amphibians, reptiles, dinosaurs and mammals – the whole shooting match. All the major extinction events are shown, too.
The site also contains a link to this YouTube video version of someone else working the timeline so you can just sit back and watch how it happens, But I recommend working the interactive page yourself. A lot more happens and is available than the video allows you to see. Note that you’ll need Flash for it to run on your computer.
I wonder how Darwin would have reacted if he were able to see his theory illustrated in this way?
SOURCES
Evolution Timeline
The Jurassic is a geologic time period of the Mesozoic Era that extends from 199.6± 0.6 Million years ago (Mya) to 145.5± 4 Mya, or from the end of the Triassic Period to the beginning of the Creataceous Period. Scientists from the University of Bristol have examined a katydid fossil from the Jiulongshan Formation (also known as the Haifanggou Formation, dated to be approxiamately 165 million years old) from Shantou Township, Ningcheng County, Inner Mongolia, China, and were able to recreate a sound made by these now extinct insects.
Like some amphibians, katydids (also known as bushcrickets) produce loud sounds by stridulation (rubbing certain body parts together). Mating calls from katydids are produced by rubbing a row of teeth on one wing against a plectrum on the other wing. What that song sounded like was unknown – until now.
Chinese palaeontologists, including Jun-Jie Gu and Professor Dong Ren from the Capital Normal University in Beijing, contacted Dr. Fernando Montealegre-Zapata and Professor Daniel Robert of Bristol's School of Biological Sciences. Dr. Michael Engel of the University of Kansas, a leading expert on insect evolution, also joined the team of reseachers.The Chinese palaeontologists produced a katydid fossil from the Jiulongshan Formation. The stridulating organs of the extinct katydid's wings were well preserved, and the Bristol researchers compared the anatomical construction to 59 living bushcricket species.They concluded that this animal must have produced musical songs.
Male katydids produced a single tone to serenade females. Using biomechanical principles, Dr. Montealegre-Zapata could reconstruct the song made by these insects. A video recording those sounds can be downloaded from the hyperlink below:
https://fluff.bris.ac.uk/fluff/u/inxhj/fqxIALCbZk8r_RBMfny__QRy/Video_S1...
Research article: Wing stridulation in a Jurassic katydid (Insecta, Orthoptera) produced low-pitched musical calls to attract females
Sonar study location along the Tonga TrenchCourtesy NOAA (with adaptation by author)Here’s something you don’t see everyday: some very amazing images of a chain of mountains heading toward a subduction zone in the South Pacific. (Make sure you watch the video at the top of this story link - it seems to take a few seconds to load). The pictures were unveiled this week at the annual American Geophysical Union meeting held in San Francisco, California.
Researchers from Oxford and Durham universities took sonar readings along the bottom of the South Pacific northeast of New Zealand that show a chain of underwater mountains being dragged westward on the Pacific plate and subducted into theTonga Trench . This chasm is second only to the Marianas Trench in seabed depth – nearly 11 kilometers (6.6 miles) deep. The computer model created from the data shows one giant volcano at the very edge of the trench breaking into huge blocks and beginning to collapse into the abyss. It’s actually pretty cool to see. Earthquakes occur less frequently near where the volcanoes are being gobbled up, and scientists differ on whether the giant broken chunks of the volcano help or hinder the subduction process, but the images clearly show the mechanism at work.
Illustration of plate boundaries and subductionCourtesy USGSAccording to the theory of plate tectonics both oceanic crust and continental crust ride atop rigid plates that migrate slowly across the globe, colliding with and pulling away from each other. There are three main types of boundary zones created by this movement: convergent (moving toward each other), divergent (moving away from each other) and transform (moving side by side). In the first example, which is the type this article deals with, the lighter oceanic plate (Pacific Plate) is subducting under the heavier continental plate (Indo-Australian Plate). The process is part of the creation and recycling of the Earth’s lithosphere – that is it’s rocky crust along with the uppermost part of the mantle. Some mantle material is forced upward in the process, and the land near these subduction zones – like that in Japan and along the coast of Chile in South America - is often populated with volcanoes. This collision of plates causes tremendous tensions to build up along the contact zone. The extreme pressure can continue building over hundreds or even thousands of years until it's too much, and the plates start to shift. All the pent-up energy is suddenly released in fits and starts in the form of earthquakes and aftershocks, as happened this year (and is still happening) in Sendai, Japan and Christchurch, New Zealand.
The underwater volcanic chain spreads across the ocean bottom in a southeasterly direction for several thousands kilometers as each mountain makes it way westward toward the trench at the rate of about 6cm per year. That's about as fast as your fingernails grow in two months. The sonar images were taken at a depth of six kilometers below the ocean surface as part of a project funded by Australia’s Natural Environment Research Council (NERC) to help determine if the massive debris from the crumbling volcanoes have any effect on the frequency of earthquakes and tsunamis in the area.
SOURCE
BBC report
Sakurajima is a stratovolcano and former island, now connected to the mainland. It is part of the Kirishima-Yaku National Park, and its lava flows are a major tourist attraction. Sakurajima volcano has frequently produced eruption plumes with significant visible electrical discharges (volcanic lightning). Its eruption in 1914 was the most powerful in 20th-century Japan. Eruptions from Sakurajima have also affected air traffic from the airport in the nearest city, Kagoshima. Large lapilli has broken the windshields of planes on several occasions, although no major incident has occurred.
The eruption at 1min 20 sec is particularly interesting.
If you look at the U.S. Nuclear Regulatory Commission’s interactive map of nuclear power plants in the United States, you will see several in states bordering the Atlantic Ocean. This prompted the Nuclear Regulatory Commission to request the U.S. Geological Survey (USGS), along with other governmental and academic partners, to research the potential for tsunamis to strike the U.S. Atlantic and Gulf of Mexico coasts, and prepare maps using sonar (originally an acronym for SOund Navigation And Ranging). Note that the March 11, 2011 earthquake near Honshu, Japan, created a tsunami that resulted in a nuclear disaster that is still being remediated.
NOAA Research Ship Nancy Foster: Nancy Foster supports applied research primarily for NOAA's National Ocean Service and Office of Oceanic and Atmospheric Research.Courtesy National Oceanic and Atmospheric AdministrationThrough this research, initiated about five years ago, the leading potential source of dangerous tsunamis to the East Coast was identified as landslides, either originating in submarine canyons or on the continental slope of the submerged margin of the continent of North America.
According to USGS marine geologist Jason Chaytor, many years of data collection and integration of existing data sets was needed in order to produce seafloor maps with the resolution needed to identify all of the relevant features for this study. The first field effort of this project was a multibeam bathymetric mapping cruise conducted aboard the National Oceanic and Atmospheric Administration (NOAA) Ship Nancy Foster from June 4 to June 16, 2011. Using echosounders installed on the hull of Nancy Foster, the science team mapped canyons and shelf regions at high resolution over more than 380 square miles (1,000 square kilometers) of seafloor from south of Cape Hatteras, located offshore of North Carolina, to the eastern tip of Long Island in New York.
Bathymetric Map of Continental Slope 150 km Southeast of New Jersey: High-resolution multibeam bathymetry collected in and between Baltimore and Accomac Canyons during the June 2011 cruise. Color key at left shows depths (in meters).Courtesy United States Geological Survey
A number of submarine landslides, some previously unknown, were either partly or completely mapped. Characteristics collected include the size and number of landslides, soil and rock properties, the water depth they occur in, and the style in which they fail. This information is often used in numerical modeling of tsunamis generated by landslides.
The scientists detailed their findings in the September/October issue of the USGS newsletter Sound Waves.
On November 10, 2011, at 17:25 UTC (or 11:25am Central Standard Time), a shallow quake occured in Greece about 11.8 miles NE of the town of Patras. According to the European-Mediterranean Seismological Centre, this earthquake had a magnitude of 5.1 (later downgraded to a 4.6) and was a relatively shallow quake at 5 km (approximately 3.1 miles) below the Earth's surface.
This region is characterized by a high level of seismicity, and small tremors are continually recorded along the coast of Patras. Another interesting aspect of Patras is that in antiquity, there was an ancient oracle, over a sacred spring, dedicated to the goddess Demeter. Professor Iain Stewart from the University of Plymouth has been studying a supposed link between ancient. sacred places in Greece and Turkey and seismic fault lines. Many ancient temples and cities lie along those fault lines and this may not be merely due to chance, but they may have been placed there deliberately.
The Temple of Apollo at Delphi with Mount Parnassus in the BackgroundCourtesy Wikimedia Commons
For example, the Oracle at Delphi has been given a geological explanation. The Delphi Fault (running east-west) and the Kerna Fault (running SE-NW) intersect near the oracular chamber in the Temple of Apollo. In that area, bituminous limestone (i.e. limestone containing bitumen, a tarlike deriviative of petroleum) has a petrochemical content as high as 20%. Analysis of spring water in the area showed the presence of hydrocarbon gases, such as ethylene. Geologists have hypothesized that friction from fault movement heats the limestone, causing the petrochemicals within to vaporize. It has been suggested that exposure to low levels of the sweet-smelling gas ethylene would induce a trance, or euphoric state. Could the naturally occuring ethylene account for the strange, prophetic behavior of the Pythia (the priestess at the Temple of Apollo)?
The Delphi research is certainly persuasive, and received favorable coverage in the popular press and Scientific American, but it has come under criticism. Critics argue that the concentrations of ethylene identified by the researchers would not be sufficient to induce a trance-like state, and thus the connection to the mantic behavior of the Pythia is dubious.
Report: Geomythology: Geological Origins of Myths and Legends
Article: Breaking the Vapour Barrier: What Made the Delphic Oracle Work?
Report: Oracle at Delphi May Have Been Inhaling Ethylene Gas Fumes
Related Report: Earthquake Faulting at Ancient Cnidus, SW Turkey
What do a banana and a chunk of coal have in common? Carbon!
Dr. Peter Griffith, Director of NASA's Carbon Cycle and Ecosystems office, spoke to twenty of us training to be Earth Ambassadors for NASA about why it's important to teach people about the way carbon moves around on our planet, in order to help them understand climate change.
He showed us this fantastic video that describes the Carbon Cycle on earth and describes how "young, fast carbon" like that in a banana differs from "old, slow" carbon, like that in coal and other fossil fuels.
Dr. Griffith also described how you can tell the difference between objects containing old carbon and young carbon by looking at the radioactive decay of carbon 14. Carbon in its normal state is called carbon 12, or C12. However, cosmic rays, like those from the sun, convert some atmospheric carbon into a slightly radioactive form called carbon 14, or C14. Over time, this carbon decays back into Carbon 12.
All living plants and animals contain some C14, since they constantly take in atmospheric carbon dioxide.
Fossil fuels like coal and oil, which have been underground for millions of years, contain only C12 (fully decayed Carbon,) while a banana still contains some C14 from atmospheric carbon dioxide the banana tree absorbed.
It is not surprising that the carbon downwind of power plants burning coal is mostly C12. Trees can also lock up carbon in their trunks and branches in for many years.
The carbon released by burning fossil fuels and setting tropical forests ablaze is carbon that would naturally have remained "locked" up. Human activities like these are creating an excess of long-lived carbon dioxide gas in the atmosphere and are causing our world's climate to warm.
NASA and other scientists are working hard to study the science of climate change. How our planet and its inhabitants will respond to the challenges resulting from this change remains to be seen.
