Literally dig deeper into the earth surface and discover what is lying right under your feet.
A large portion of the famed White Cliffs of Dover collapsed sending thousands of tons of chalk into the English Channel. The chalk cliffs, which stretch for about 8 miles along England's southern coast, are the result of deposition of "coccolith biomicrites formed from the skeletal elements of minute planktonic green algae" that were once suspended in the upper water column of an ocean during the Cretaceous Period. The soft chalky limestone is composed mainly of calcium carbonate, nodular flint seams, and marine fossils. It's suspected that the rain-soaked cliff face was loosened from recent freezing. The Daily Mail has some very cool photos of the 300-foot rockfall. And here's a link to Discovering Fossils with info about the geology of the cliffs and fossils that can be found there. This informative website is written and designed by Roy Shepherd.
Courtesy Mark RyanLast October, I attended the Geological Society of America’s annual meeting held here in Minneapolis. The convention presented plenty of opportunities to hear the latest ideas in geology, paleontology, and planetary science but the highlight for me was being able to join a GSA field trip on Lake Superior aboard the research vessel, the Blue Heron.
Courtesy Mark RyanThe 86-foot vessel is owned by the University of Minnesota-Duluth (UMD) and operated by the Large Lakes Observatory (LLO), an organization created in 1994 for investigating the geochemical and geophysical properties of large lakes, and their global impact. To accomplish this research, the LLO required a worthy vessel for limnological research, and the Blue Heron was purchased just three years later.
The vessel docks at the Corps of Engineers Vessel Yard on Park Point (aka Minnesota Point), a natural sand bar separating Duluth’s harbor basin from Lake Superior. The ten-mile spit was created by the lake’s wave action on material deposited by the St. Louis river, and is supposedly the largest freshwater sand bar in the world. Field trip leaders Doug Ricketts, the marine superintendent at LLO, and Charlie Matsch, professor emeritus of geology at UMD, greeted arriving participants and divided us into two groups. While one group spent the morning on Lake Superior, the other visited geological highlights in the Duluth area with professor Matsch. In the afternoon the groups switched places.
I joined the morning shift on the lake with a dozen geologists made up of GSA attendees from Minnesota, Wisconsin, and City University of New York. Besides Doug Ricketts and the ship’s five crew members, regents professor Tom Johnson, and the director of the LLO, professor Steve Colman, were also on hand to help demonstrate and explain the Blue Heron’s research capabilities.
Courtesy Mark Ryan
Courtesy Mark RyanWe shoved off right on schedule, heading across the harbor toward the Superior entrance on the Wisconsin end of the sand bar. The crew spent this time going over the ship’s safety rules - how to descend ladders, which alarms meant what, how to communicate with the bridge - that sort of thing. We then made a quick tour of the facilities. The Blue Heron is equipped with a wet lab on the open deck and two dry labs inside, and all sorts of data gathering equipment for geophysical, geochemical, and biological sampling. These include multibeam sonar for profiling the lake bottom and sub-bottom, several coring instruments for collecting sediment samples, and water samplers able to collect at various depth levels in the water column while also measuring such things as temperature, depth, pH levels, and conductivity. There’s gear for tracking lake currents, and plankton nets and a trawl for gathering biological data. Inside, both above and below deck, computers record, display and analyze the gathered data. Many of the off-ship instruments can be monitored and controlled on-board from computer consoles.
Courtesy Mark RyanThe R/V Blue Heron is outfitted to carry five crew members and six researchers and can stay on the lake, around the clock, for 21 days between port calls. It’s used mainly on Lake Superior, the largest and least studied of the Great Lakes. Shipboard amenities are sparse (there’s no television or DVD) but include eleven bunks, a full galley for food preparation, dining table, shower, and of course, the "head", or as you landlubbers like to call it, the toilet. Internet service is sometimes available when the vessel is near shore.
Courtesy Mark RyanUpon entering Lake Superior, the crew set to work demonstrating some of the vessel’s science gear, which is pretty much the same kind of instrumentation used in oceanographic research. Just beyond the Superior entrance, the EchoTech CHIRP/sidescan sonar tow fish was lowered from the Blue Heron’s stern. This bright yellow instrument is towed underwater behind the vessel as it makes several passes over the lake bed, and able to gather hydrographic and bathymetric data. One function is to send out an intermittent, low frequency “chirp” pulse that can penetrate the sub-bottom and record changes in its geophysical properties. The sonar data is processed using on-deck computers.The first demonstration was a scan of the underwater channel of the Nemadji River, a Wisconsin tributary to the lake. The mouth of the Nemadji has been drowned by a process called post-glacial rebound or more scientifically, differential isostatic rebound. During the last ice age, a mile thick sheet of ice covered the region and placed enormous pressure on the earth’s crust, depressing it downward. As the glaciers retreated, that enormous weight was gradually removed, and the lake basin began to rebound (a process still going on today). But the northern and eastern ends of Lake Superior basin are rebounding at a faster rate, tilting the water southward and to the west and subsequently flooding those areas of the shoreline.
Courtesy Mark RyanAs the submerged tow fish was doing its stuff, we all gathered at a couple workstations in the lower deck dry lab to watch as images appeared on the computer screens. In one, you could plainly see the distinct profile of the Nemadji’s drowned riverbanks.
Courtesy Mark RyanThe other monitor displayed bathymetric information being picked up by the duel frequency sidescan sonar. Printouts of the lakebed topography, created from a mosaic of stitched-together scans, were laid out on a worktable with several charts and maps.
Courtesy Mark RyanFor the next demonstrations, the Blue Heron moved out several miles onto the big lake. We’d all been warned of the lake’s fickle weather, and told to bring proper attire, just in case. Having been raised in Duluth, I was well acquainted with Superior’s moodiness, especially in autumn, so I brought along rain gear, a jacket, and an extra sweatshirt, expecting the worst. But I was most comfortable in jeans and a t-shirt. Cloud cover was sporadic, and while the water temperature was only around 49 degrees, the air temperature hovered in the mid to upper 70s during the entire excursion. We couldn’t have hoped for a nicer day; a perfect Duluth day, as we used to call them.
While some of the group watched the crew prepare for the next presentation, others enjoyed lunch (sandwich, chips, fruit and a cookie) at the galley dining table. During my lunch break Tom Johnson told me the story of how the university came to own the research vessel. In her previous life, the Blue Heron was known as the Fairtry a commercial fishing trawler that fished the Grand Banks in the northwest Atlantic (like the Andrea Gail in The Perfect Storm). UMD purchased it in 1997 and Tom sailed it from Portland, Maine, through the St. Lawrence Seaway and across the Great Lakes to Duluth. Despite some minor engine problems at the start, he said it was a fantastic two-and-a-half week trip. Over the next winter, the Fairtry was converted into a limnological research vessel and re-christened the Blue Heron.
Courtesy Mark RyanMeanwhile, out on the back deck, the crew was ready to launch the next instrument, a carousel of canisters called Niskin bottles used for sampling the water column.
Courtesy Mark RyanThis device is lowered into the lake and controlled remotely from the deck, and can collect samples at various depths into any one of its dozen canisters. It can also measure temperature, conductivity, pH balance, transparency, dissolved oxygen levels and other tests. After deployment, marine technician, Jason Agnich, sat at a computer workstation just inside the hatch, and easily controlled the carousel with a joystick while monitoring its progress on a couple electronic displays.
Courtesy Mark RyanWe moved a little farther down lake where two coring instruments, a spider-framed multi-corer, and an arrow-like gravity corer were put into action. The first can collect several shallow core samples by lowering it by winch to the lakebed, while the latter is dropped like a giant dart deep into the sub-bottom sediment for one large core.
Courtesy Mark RyanAfter each was raised back to the surface, the collected core samples were removed from their tubing and laid out on the wet lab table for study. We all huddled around the workbench as each core was cut open with a knife so participants could take a closer look. The sediment cores were composed of a densely packed fine-grained mucky silt as brown as milk chocolate, and appeared more appropriate for a scatological study than a geological one, to me anyway. But that didn’t stop some of us from taking home a small plastic bag of it as a souvenir.
Courtesy Mark Ryan
Courtesy Mark RyanAs we made our way back toward the harbor, I stood at the starboard rail and took in the beautiful autumn colors lighting up the lake’s distant North Shore. We were three, maybe four miles offshore but I was able to pick out my old stomping grounds in Duluth’s east end. The old neighborhood – like much of the city - was built up on terraces formed by past shoreline configurations of prehistoric Lake Superior. Duluth’s Skyline Parkway, a boulevard that skirts the hilltop across the length of the city was built on an old gravel beach line of Glacial Lake Duluth when the water surface was nearly five hundred feet above its present level. The bridge over the mouth of the Lester River was just barely discernible from where I stood but it was easy to spot the large swath of dark pine forest that encompassed Lester Park and Amity creek (the western branch of Lester river) where my friends and I used to hang out. It’s also where Charlie Matsch would guide our group later in the afternoon. He brought us there to examine the Deeps, my favorite old swimming hole carved out of the massive basalt flows that extruded from what’s now the center of Lake Superior during the Mid-continental rifting event that took place nearly a billion years ago.
Courtesy Mark RyanWe returned to port through the Duluth entrance, and as we entered the canal captain Mike King announced our arrival with a blast of the Blue Heron’s air horn. Duluth’s landmark Aerial-Lift Bridge, already raised for our return entry, responded in kind with a shrill loud blast of its own. Tourists lining the pier called out and waved as we passed the old lighthouse and rolled toward the harbor. We all waved back and I have to say it was kind of a thrill, for me anyway, after having participated in the same ritual, oh probably a hundred times in the past but always from the pier not from a vessel.
Courtesy Mark RyanThe Blue Heron swung in through the harbor, and soon we were back at port where we started at the Corps of Engineers Vessel Yard. Charlie Matsch was there to greet us and take for the second leg of the field trip.
Charlie took us first up the hillside to the rocky knob near the landmark memorial Enger Tower where he showed us some interesting exposures of gabbro, an intrusive rock common to the geological formation known as the Duluth Complex. Much of the bluffs west of downtown Duluth are composed of this dark, course-grained mafic rock. Now, I admit I enjoy a geological outcrop as much as the next guy (especially when a real geologist is explaining it), but it was the sweeping view from the hilltop that drew my attention.
Courtesy Mark RyanThe lake and harbor and much of the St. Louis river bay stretched out below us in an array of vivid blues contrasting with the bright reds and golds of autumn. On one side of the harbor, bridges, railroads, and structures of industry jutted out on Rice's Point toward Wisconsin, paralleled on the other side by the slender ribbon of Park Point. As I took in this grand vista, a small, barely discernible bluish blur of movement caught my eye. There, cutting through the harbor, the Blue Heron headed southward toward the Superior entrance for another run on the great lake.
A team of Russian researchers have successfully drilled through miles of glacial ice and finally reached the surface of a long-buried lake. Scientists estimate the gigantic body of water, named Lake Vostok, has been buried under ice for more than 20 million years, and think the lake could contain forms of microbial life that existed before the Ice Age.
These geniuses obviously need to get a Netflix subscription for their research station. How many versions of this movie will it take before people pay attention?
Story on Earthlink
Courtesy Public domainThis week's "Image of the Week" entry at Scientific American's Layers of the Earth blog is this drawing by Gregorio Piccoli del Faggiol (1680-1755) an 18th century Italian engineer and cartographer. The title of the illustration (translated from Italian) is: "Description of a cave in the mountains of Verona where many bones of beasts from the deluge can be observed". Created in 1739, the topographic map of the Dolomites is accompanied with a stratigraphic column of the rock layers observed there. And that's what makes this map so special; it may be the oldest of its kind. That's pretty cool, especially for someone like me who likes collecting antique engravings and illustrations related to the earth sciences. I'd love to own an original copy of it.
Paleontologist Dr. Howard Falcon-Lang found the 314 slides while searching through the vaults of the Survey headquarters near Keyworth, UK. Each slide contains a polished thin section of a fossil plant, prepared for viewing under a microscope. But the best thing about the discovery is that some of the slides are of specimens collected by the young Charles Darwin during his legendary voyage on the Beagle. Darwin’s theory of evolution and subsequent book On the Origin of Species resulted from much of what he discovered during the five-year voyage. Among the specimens collected by Darwin is a piece of petrified wood from an island off the coast of Chile in 1834.
Falcon-Lang figures the collection has been languishing unregistered in the cabinet for 165 years. Joseph Hooker, a botanist and close friend of Darwin, worked briefly for the Geological Survey in the early 19th century, and given the job of cataloging the collection. But before Hooker could properly register the fossils, he left on an expedition to the Himalayas and the collection was soon forgotten. In the passing years the cabinet got moved several times until it reached its current storage place deep in the recesses of the Geological Survey where it was found in April of last year.
According to Falcon-Lang the lost fossils, some of which can be viewed on line, will add greatly to current science, and he expects some great scientific papers to result from the collection.
You don't see this every day - a new land mass forming right before your eyes. This video shows a giant shield volcano erupting beneath the Red Sea and forming an island on the surface. Fishermen from Yemen first noticed erupting magma about a month ago, and now an island has appeared, adding to the chain of islands called the Zubair Island Group. The huge volcano sets on a rift where the African and Arabian continental plates are pulling away from each other. More information can be found on the Smithsonian Science website.
Courtesy NASAMan, I had this dream last night that my brother and I had each taken a long trip, and at the end of the trips we met up and floated around the sky while singing to each other about our feelings. What a strange dream. I think it means that I’m afraid of death. That’s what my dream analysis book says anyway, just like it says for every dream.
On an unrelated note, one of NASA’s latest experiments, the “GRAIL mission,” is ticking away smoothly.
If, like me, you assumed that the GRAIL mission was a lot like Indiana Jones and the Last Crusade, I’m afraid you’re about to be sorely disappointed. “GRAIL,” in fact, stands for “Gravity Recovery And Interior Laboratory,” so you shouldn’t expect any bullwhips or crusty old knights. No, the GRAIL mission will be carried out by the two identical satellites that just reunited in orbit around the moon, after a slow trip from Earth (Apollo program vessels made it to the moon in just three days, but the GRAIL satellites sort of took a scenic route that required less energy to get to the moon, but a lot more time—between three and four months.)
The satellites arrived at the moon on different days (the 31st and the 1st), but now that they’re back in the same neighborhood they’re going to be traveling around the moon together at about 35 miles above the surface. As they move, they’ll be transmitting radio signals to each other, which will allow them to precisely calculate the distances between them. As one or the other of the satellites flies over an area of the moon with greater or lesser gravity, the distance between the satellites will change slightly.
Because tiny differences in gravity are determined by the interior composition of an object in space*, these satellites will tell us more about the inside of the moon, and how it formed. And because the moon originally came from Earth, we’ll learn more about the formation of our planet from this mission as well.
*More mass means more gravity, so the satellites will be able to detect not only visible features on the moon, like hills and craters, but underground structures as well. Moons and planets after all, aren’t totally uniform inside—they’re less like giant marshmallows than giant scoops of rocky road ice cream.
The things that happen in space … amiright? Crazy!
Courtesy US Geological Survey Photographic LibraryToday marks the bicentennial of the start of the historic New Madrid earthquake series, which began at 2am on December 16, in 1811. The quakes were so powerful, large areas of land uplifted and sank creating new lakes and swamps, and causing islands to disappear. Large waves spawned by the tremors raked across the banks of the Mississippi causing massive landslides, and even briefly changing the course of the mighty river.
Named after the nearby river village of New Madrid in the then Louisiana Territory (now Missouri), the quake and its many aftershocks affected an area 10 times larger than the famous 1906 San Francisco earthquake. Luckily, the New Madrid area was sparsely populated when the line of strong earthquakes took place, as they were the strongest recorded earthquakes ever to take place east of the Rocky Mountains.
Earthquakes of such magnitude as those that struck New Madrid (~ 7.0) typically occur along plate boundaries - areas where one tectonic plate is colliding with another, such as along the West Coast's San Andreas Fault. The mid-section of the country sets on only one plate - the normally stable North American plate. Faults do run through it, such as the Cottonwood Grove and the Reelfoot faults which some scientists hypotheisze were responsible for the New Madrid series.
But researchers don't agree on what caused the strong intraplate earthquakes. They could have been triggered by other distant earthquakes or by the release of energy built up by the heating of the crust from an upper mantle magma plume or from isostatic rebound - that is the release of stresses caused by the retreat of glaciers that once covered the region.
Whatever the cause and despite new data being gathered by present day geologists, the New Madrid earthquakes were an historic anomaly that remain wrapped in mystery.
Courtesy Mark RyanYou’d think since the decision handed down in the Kitzmiller et al v. Dover court case in 2005 creationists would have given up trying to force their decidedly non-scientific views into public school science curricula. But apparently that’s hasn’t been the case. Those touting pseudo-scientific explanations such as intelligent design (creationism all dressed up in a monkey suit – as someone cleverly put it) are still at it, trying to get their religious-based ideas included in science classroom discussions.
A talk given by Steven Newton at this year’s Geological Society of America meeting in Minneapolis dealt with ways to counter the methods creationists use to push back against the information presented in earth science classes within the K-12 public school settings. The talk was one of several in a session titled, Geoscience Education X: Overcoming Threats to Earth and Space Science at K-12 Levels.
According to Newton, who’s with the National Center for Science Education (NCSE), the creationists’ methods amount to nothing less than sabotage.
Some of the feedback he said he heard from the nation’s public schools helps illustrate the kind of resistance earth science teachers continue to get from students, parents, and even school administrators. When a controversial subject such as evolution or climate change is being presented, teachers report being told to “tone it down” or “skip that chapter”* or to “teach both sides” (why just two sides? why not 200?). Newton said teachers also heard pleas of “don’t offend parents” from school administrators.
Of course, the earth sciences aren’t the only disciplines under attack. Just this past week, a story came out of Kentucky about how the school superintendent in Hart County complained in a letter to the state’s education commissioner and board of education members that he was concerned to learn that the state testing guidelines for biology considered evolution as a fact while at the same time “totally omitting the creation story by a God who is bigger than all of us.” It’s a harrowing example of the anti-science attitudes that are still prevalent in our country, and how creationists continue to threaten science education.
These don’t-rock-the-boat mitigations of scientific knowledge are harmful to science in general and aren’t doing the students any favors. Spoon-feeding watered down information or adding non-scientific knowledge into the mix confuses students and deprives them of a proper science education. Strong suggestions such as “teach the controversy” (when there is none) serves no purpose other than as a way to force religious or irrationally-based information into the public schools.
The anti-science crowd uses various means of attack to undermine geoscience knowledge in the schools and elsewhere. It questions the fossil record, pointing to something like the 19th century Piltdown Hoax as an example of how fossils and their interpretation can be faked. They make a huge leap of logic and argue that since one fossil was faked then all fossils must be questioned. The validity of radiometric dating is thrown into doubt with misinformation such and out-of-context or re-edited quotes from legitimate scientists, and even salted quotes.
Some worn-out creationist ploys have been lurking about for years, stories of dinosaurs spotted living in the Congo, fossil human footprints discovered alongside dinosaur tracks, a stegosaur figure found in the carvings of an ancient temple in Cambodia, a plesiosaur carcass hauled up from the depths by a Japanese trawler. These and other stories have either been thoroughly debunked or have failed to ever present any concrete evidence, yet continue to creep into otherwise serious evolution discussion,
The Internet is clogged with creationist viewpoints, some sites disguised with scientific-sounding domain names. This requires students to be alert and very careful about their research sources.
In hopes of legitimizing their point of view, creationist organizations of late have sponsored lectures and propaganda films in venues rented from legitimate scientific institutions such as they did at Southern Methodist University (SMU) and the California Science Center. When objections are raised and such events cancelled, the creationists proclaim it amounts to nothing less than censorship of ideas. But creationist ideas have always been poor in scholarship, lacking peer review or any kind of objective testing. Many are totally untestable.
Newton also warned against what he considers mistaken solutions to the problem of creationist pushback. Debating pseudo-scientists or giving their ideas equal time in the classroom only gives them unwarranted credibility. And why “teach the controversy” when there is none in the first place?
But, Newton insists that this doesn’t mean earth science teachers should avoid dealing with the pushback. Creationist tactics evolve over time, coming up with new ways to attack legitimate science. And just as new vaccines are developed to fight evolving flu viruses, science teachers need to stay a step ahead of the creationists and counter their anti-science attacks with a vaccine of cold, hard, scientific facts. Perhaps this affliction can be wiped out in our lifetimes.
*Attacks against science aren’t reserved only for the schools. Just this past week biologist and science-blogger PZ Myers alerted his readers to the fact that the Discovery Channel had purchased rights to broadcast the BBC documentary series by David Attenborough titled “Frozen Earth” but that it wouldn’t be including the last episode regarding climate change because the subject was too controversial. (Evidently, after a flood of well-deserved complaints the Discovery Channel has now reversed its decision and will air all seven episodes).
Courtesy 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.
Courtesy 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.