Literally dig deeper into the earth surface and discover what is lying right under your feet.
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.
Courtesy Anne Burgess
A rock mass visible at the surface is named an "outcrop" by geologists. Most of these outcrops are made of a single, homogenous kind of rock (e.g. basalt) but in many cases rocks are layered, fractured, cleaved, or show more complicated patterns on their surface. At high temperatures and pressures inside the earth, rocks can move slowly, or can fracture creating fault planes. Outcropedia is a website meant to show a collection of such outcrops.
Outcropedia is the brainchild of three structural geologists : Cees Passchier, Mark Jessell, and Hermann Lebit. It uses a GoogleEarth template, and by clicking on a datapoint, you can see a photograph or drawing with explanatory text. Many of the outcrops included are in remote areas of planet Earth. Outcropedia welcomes new submissions, so if you have an image of an outcrop, submit it for addition!
Courtesy Photo by Heather Rousseau ©Denver Museum of Nature and ScienceThe last talk I attended at the Geological Society of America (GSA) convention this past week was one of my favorites. It was an update of the Snowmastodon Project given by Kirk Johnson, chief curator at the Denver Museum of Nature and Science (DMNS). Just one year ago, a construction worker bulldozing for a dam-building project at the Zeigler Reservoir near Snowmass Village in Colorado unearthed a mammoth tusk. Paleontologists and archaeologists from the Denver museum were called in, and excavation of a small portion of the drained reservoir bottom soon got underway. The museum crew worked for just one month, until November 14, 2010, when snowfall halted the project. Then last spring scientists returned to the site and were allowed just 51 days to excavate the fossil deposits before the Snowmass Water and Sanitation District resumed their expansion work on the reservoir.
This time more research experts from the US, Canada, and England joined the dig along with a slew of interns and volunteers, totaling some 233 people working on the project. Over the next seven weeks excavation at the Zeigler Reservoir site progressed at a frantic pace. According to Johnson, anywhere from 15 to 90 diggers were on site each day digging out fossils from the ancient peat and mud deposits, from what once were the shores of a small glacial lake. Despite the short window of opportunity, the sheer number and diversity of fossils from the dig site has been truly remarkable.
Courtesy Dantheman9758 at en.wikipediaOf the nearly 5000 bones and skulls exhumed from the Snowmass fossil site, more than 60 percent were of mastodons (Mammut americanum) representing at least 30 individuals in various stages of life. The other 40 percent of the fauna included mammoths (Mammuthus columbi), camels, horses, giant bison (Bison latifrons) and ground sloths (Megalonyx jeffersonii), otters, muskrats, minks, bats voles, chipmunks, beavers, bats, rabbits, mice, salamanders, frogs, lizards, snakes, fish, and birds, and iridescent beetles. No large carnivore remains were found in the deposits, and human remains were absent as well, although archaeological techniques were used during the dig just in case any were uncovered.
Flora from the prehistoric tundra environment included pollen, green leaves and cones, and tree logs, some with their bark still intact.
So far, age estimates for the deposits range between 43, 000 to 130,000 years old although further dating tests should narrow that down.
The talk included several photos of what Johnson termed “Flintstone moments”, i.e. shots of field workers posing with massive mammoth or mastodon femurs or tibia. And Johnson marveled at the incredible state of preservation of many of the fossils displayed. Some of the bones, he said, still emitted a very strong funk.
In terms of sheer number of bones and ecological data, Snowmastodon ranks up there as probably one of the best high altitude Ice Age ecology sites in the world, and certainly the best mastodon fossil site. A team of researchers at the DMNS lab will spend the next year and a half cleaning, cataloging, and analyzing all the fossils found at the Snowmass dig site, water was to be reintroduced into the reservoir on Oct. 13. Despite the loss of the site, the field crew did a tremendous job in the time they were given to excavate the fossil-rich site. And Kirk Johnson didn’t hide his excitement. In closing his talk, he said “It was one hell of a year!”
Courtesy Mark RyanNext week the Geological Society of America is convening in Minneapolis, Minnesota for the GSA's 2011 Annual Meeting and Exposition. That means something like 6000 geologist, paleontologist, hydrologists, and other ologists from around the world will be in our area to share new ideas and hobnob with their fellow earth scientists. The four-day event, which is hosted by the Minnesota Geological Survey, runs from Sunday, October 9 through Wednesday, October 12 at the Minneapolis Convention Center, and will include special lectures, award ceremonies, poster sessions, an exhibit hall, and several hundred technical talks covering a full range of geology-related subjects. There will also be a silent auction, a photo exhibition, short courses (available to non-registrants), and a screening of the locally produced documentary, “Troubled Waters: A Mississippi River Story”. Field trips happening before, during, and after the official meeting dates will give visiting geologists an opportunity to take in some of the spectacular and diverse geology that Minnesota and the Upper Midwest has to offer, not to mention the fall colors. This year’s meeting is titled “Archean to Anthropocene: The Past is the Key to the Future”, and even if you can’t make it to Minneapolis, you can download a cool poster of the event here.
Courtesy Mark RyanSummer seems to have finally arrived in Minnesota and that can mean only one thing: another season of fossil collecting is here. This year, due to near-record snowfall and spring floods, the St. Paul Parks department delayed issuing collecting permits for Lilydale Regional Park, one of the best fossil collecting sites in the Twin Cities. The park is located on the bluffs across the river from downtown St. Paul and is the former quarry and manufacturing site of the now defunct Twin Cities Brick Company. You can enter the park from above near Cherokee Park, or below from Harriet Island. Either way entails hiking a bit of a distance. There's a parking lot just off Water Street, and street and lot parking near Cherokee Park. Download map
Courtesy Mark Ryan (photo)The first permits for the "Brickyards" were issued last week, so a few of us from the Science Museum headed over to the park to spend some time searching for the fossilized remains of the marine life that once populated Minnesota during the Late Ordovician Period some 460 million years ago. Back then, much of the state was covered by a shallow, tropical sea, situated below the equator. Times certainly have changed.
The abundant fauna living in that prehistoric sea included reef-building bryozoans (the most commonly found fossil), brachiopods, lily-like crinoids, gastropods, horn coral, predatory cephalopods and everyone’s favorite, trilobites.
Courtesy Mark RyanIn general, there are three areas to collect fossils at Lilydale: the East, Middle, and West clay pits. Signs posted in several spots help direct you to collecting locations, but once you’re in the park you can find fossils just about anywhere.
The fossil quarries at Lilydale expose the Platteville and Decorah Formations that overlie the St. Peter Sandstone that forms the base of the bluffs found along the Mississippi. The Decorah shale here is about 90 feet thick and easily reconstitutes back into very sticky clay whenever rain or seeping ground water mix with it. But that usually won’t deter most hardened fossil hunters.
Courtesy Mark Ryan
Courtesy Mark RyanWe had a pretty good day at Lilydale finding the usual crop of fossils, such as crinoid rings, brachiopod shells, and bryozoa branches. Chris pointed out some trilobite heads (cephalon) Ashley and I had overlooked in a couple small slabs of shale. John picked up a nice receptaculites specimen just setting on the ground. Later, while scanning the bluff, a piece of gray shale caught my eye. It was about six-inches in diameter and contained several brachiopods. But upon closer examination, I counted the remains of at least a dozen trilobites, mostly the heads of Eomonorachus intermedius.
Courtesy Mark RyanBut what my fossil possessed in quantity, John’s big find of the day overshadowed in quality. Picking through the clay piles that had slumped down from the top of the quarry since last fall, John plucked out a very well-preserved, rolled specimen of Isotelus gigas?, measuring about 1-1/2 to 2 inches across! It’s the largest trilobite I’ve witnessed come out of the Decorah. All the ones I’ve ever found were incomplete and maybe the size of a kernal of corn at best. But John’s fossil was a doozy. Unrolled it would measure a good 3 inches in length, if not more. I don’t like being outdone so I told John there’s no reason for him to hunt for fossils anymore - he’ll never find another specimen like that. But we both know he won’t be able to stop. That’s just the way fossil hunting is; there’s always the possibility of discovering a bigger and better find next time you go out.
Courtesy Mark RyanMany of the Decorah fossils can be found weathering out on the surface, so you don’t need much in the way of tools. Some people like to bring a large bucket to serve as a stool while they’re in the quarries, and then for carrying out their fossils when leaving. I usually bring some plastic sandwich or freezer bags to hold smaller fossils. Some people use tissue paper or aluminum foil to wrap and protect their more precious finds. I do that sometimes. The clay pits also contain lenses of fossiliferous rock forming what’s known as "shell hash" – a chaotic jumble of fauna preserved in a matrix of limestone or shale. A rock hammer sometimes come in handy for breaking up large slabs into smaller, more portable ones, or for climbing the quarry banks.
Courtesy Mark RyanIf you go to hunting in the Lilydale quarries, you’ll want to bring along some water, and bug dope - mosquitoes weren’t yet a problem, but a couple wood ticks showed up. The driest parts of the quarry are of course in the sun, so if you're like me and burn easily, and don't want to spend most of your time searching in the muddier shade, it’s best to apply some sun-block lotion to your exposed skin. John also spotted several patches of poison ivy while we were scouring the West Clay Pit so you should keep that in mind, too. It’s an isolated area so be aware of your surroundings and it’s probably best to go with someone else. The quarry walls and hillsides can be unstable and treacherous. I've seen people take serious tumbles down the quarry face. Be aware, too, that there are no bathroom facilities at the quarries. There are lots of woods and bushes, though.
If you’re going to be there for a while you might consider bringing something to eat, too. Ashley brought a delicious seven-course gourmet meal for all of us to enjoy. Okay, that’s a slight exaggeration (it was only three courses), but after a few hours of intensive fossil hunting it sure tasted like one. Ashley has secured for herself a guaranteed slot in all future fossil hunting expeditions.
For information on acquiring a fossil-collecting permit for Lilydale, check out the Lilydale Regional Park permit page. Individuals and small groups of less than ten people pay $10 for a day permit. Larger groups pay more.
The Minnesota Geological Survey offers a nice information brochure about local geology, collecting, and identifying fossils at Lilydale and elsewhere around the Twin Cities. Download it here
Courtesy Mark RyanI've listed a few more websites below to help get you started and make your fossil-collecting excursion to Lilydale more fun and informative. In general, hunting for fossils is kind of like fishing; you get to enjoy the outdoors, you get to occasionally make some nice catches (finds), and you get to bring them home and clean them. But best of all (besides not having to eat them), you get to boast to your friends about "netting" some sea creatures that are over 450 million years old. That, for me, is a fish story that's way more impressive than any fish tale concerning some old lunker that got away. So get out there and dig up the next great cephalopod fossil. You'll know exactly what I'm talking about.
List of fossil sites and equipment
More trilobite info
More about horn coral
Collecting Fossils in Minnesota (previous Buzz post)
Minnesota DNR info page on fossils
Fossil Collecting in the Twin Cities
Lilydale trail map
Lilydale Regional Park
More about Lilydale Regional Park
Courtesy Public domain (via Wikipedia)James Hutton, born this day in 1726, was a Scottish farmer and doctor (although he never practiced medicine), and is often regarded as the "Father of Modern Geology". Through direct observations and studies of geological features in and around Great Britain, Hutton conceived the scientific ideas of uniformitarianism and deep time that directly challenged the popular biblical-based notion of the Earth being only 6000 years old. Hutton was a founding member of the Royal Society of Edinburough and his book Theory of the Earth set the basis for modern geological theory.