Stories tagged Earth and Space Science

Apr
13
2014

Tiktaalik roseae: Field Museum of Natural History
Tiktaalik roseae: Field Museum of Natural HistoryCourtesy Eduard Solà via Wikipedia
If you missed last week's PBS broadcast of Your Inner Fish, the documentary based on paleontologist-anatomist Neil Shubin's book by the same name, you have another chance to catch up on the first of three segments on the web. It's an excellent opening segment of the 3-part series, but is only available (for free!) right here through April 23, 2014.

The series deals with Shubin's search for the connections we all have with our fishy and reptilian ancestors. His discovery of the remarkable transitional fossil named Tiktaalik roseae on Ellesmere Island in the Canadian Arctic has added great evidence of our ties with our distant piscean relatives. The flat-headed, 375 million year-old Tiktaalik possessed the exact features - such as both lungs and gills, a wrist and neck - that you'd hope to find in a transitional form between swimming fish and land-walking tetrapods.

The next episode, titled Your Inner Reptile airs Wednesday, April 16th on your local PBS station. It's on here in the Twin Cities at 9pm but check your local listing for times in your area.

In the meantime, watch the first episode, and read about some of the reaction to Shubin's find here, here, and here.

LINKS
University of Chicago Tiktaalik roseae page

Feb
17
2014

Kilauea at night: a massive magma chamber has been detected beneath the volcano's East Rift Zone.
Kilauea at night: a massive magma chamber has been detected beneath the volcano's East Rift Zone.Courtesy Mark Ryan
Researchers from the University of Miami Rosentiel School of Marine and Atmospheric Science have detected a new, massive magma chamber beneath Kilauea, the most active volcano in the world.

By analyzing seismic waves that traveled through the volcano, scientists from the school's geology and geophysics departments have been able to piece together a 3-dimensional velocity model of what's taking place deep below the volcano's caldera.

"It was known before that Kilauea had small, shallow magma chambers," said Guoqing Lin, lead author of the study. "This study is the first geophysical observation that large magma chambers exist in the deep oceanic crust below."

Located in oceanic crust between 5 and 6.8 miles beneath the volcano's East Rift Zone, the new chamber has been determined to be several kilometers in diameter. The seismic data also revealed that it's lava is composed of a slushy mixture of about 10 percent magma and 90 percent crystal.

According to co-author and professor of geology and geophysics, Falk Amelung, the information is useful in understanding magma bodies and a high priority for the researchers because of the possible hazards created by the volcano.

"Kilauea volcano produces many small earthquakes and paying particular attention to new seismic activity near this body will help us to better understand where future lava eruptions will come from," he said.
Kilauea has been active for more than 30 years and is located in Hawaii Volcanoes National Park on the Big Island of Hawaii.

The paper appeared in a recent edition of the journal Geology.

SOURCES and LINKS
Science News story
LiveScience story
2007 video of Kilauea erupting
More about Kilauea

Feb
14
2014

The Canadian Rockies: Source of a new treasure trove of amazing Cambrian fossils
The Canadian Rockies: Source of a new treasure trove of amazing Cambrian fossilsCourtesy Mark Ryan
Just over a century ago, paleontologist Charles Doolittle Walcott discovered a truly remarkable fossil quarry in British Columbia. The site, known as the Burgess Shale, was found on Mt. Field in Yoho National Park, and contained an abundant amount of fossilized remains of soft-bodied creatures - several new to science - from the Cambrian Period around 505 million years ago. In 1989, paleontologist Stephen Jay Gould detailed the spectacular find and its implications in a book titled, "Wonderful Life: The Burgess Shale and the Nature of History".

Burgess Shale trilobite: Science Museum of Minnesota collection.
Burgess Shale trilobite: Science Museum of Minnesota collection.Courtesy Mark Ryan
This week, a newly discovered fossil site, located in the same shale formation high in the Canadian Rockies but 26 miles southeast of Walcott's quarry, was announced in the journal Nature Communications. The new location, named Marble Canyon, is proving to be another Lagerstätte, a sedimentary deposit of extraordinary and exceptionally preserved fossils. The discoverers report that of the 3000 specimens found so far and representing 55 species, about half are invertebrates also found at the Walcott Quarry, and in some cases are more abundant and better preserved.

"[T]here is a high possibility that we'll eventually find more species here than at the original Yoho National Park site, and potentially more than from anywhere else in the world," said lead author Jean-Bernard Caron, an invertebrate paleontologist at Toronto's Royal Ontario Museum.

So far twenty-two percent of the species discovered at Marble Canyon are new to science. The formation is estimated to be about 100,000 years younger than the original site. China's Chengjiang fossil beds have produced some of the same kinds of animals found at Marble Canyon and is about 10 million years older.

Arthropods (e.g. trilobites) are the most common animals found in the Burgess Shale, and finely preserved fossils from the new site provide remarkable views of neural tissues, retinas, corneas, some internal organs.

Back in 2012, Gaines and his colleagues followed the Burgess shale exposures on foot, trekking across the mountainsides in hopes of finding new fossils sites. What they discovered at Marble Canyon is far more than they could have wished for.

"I think the most profound implication is that the Burgess Shale can't just be the only one that there is," Gaines said. "There's a lot more out there in the Canadian Rockies and other places."

Any fossil remains uncovered at Marble Canyon and at similar sites will only add to our understanding of evolution and how complex life developed during the Cambrian Explosion.

Gallery of new Burgess Shale fossils

SOURCES and LINKS
Nature Communications
ScienceDaily story
"Wonderful Life" by Stephen Jay Gould
LiveScience story
Previous Burgess Shale Buzz story
More about the Burgess Shale

Dec
28
2013

Restoration of Haplocanthosaurus: a Late Jurassic sauropod whose remains are found in Colorado, Utah, and Wyoming.
Restoration of Haplocanthosaurus: a Late Jurassic sauropod whose remains are found in Colorado, Utah, and Wyoming.Courtesy FunkMonk via Wikimedia Commons
The partial remains of a somewhat rare sauropod dinosaur have been discovered in Old Snowmass, near Aspen, Colorado. Paleontologist John Foster of the Museum of Western Colorado in Grand Junction said that fossils of a Haplocanthosaurus were found by college student Mike Gordon in 2005 on land owned by his mom and stepfather. If you remember, Snowmass was the site near Aspen where a large collection of mammoths, mastodons, and other Ice Age mammals were uncovered back in 2010. This latest discovery is about six miles from the other site but in a much, much older rock layer. Foster said the Lower Morrison Formation, from where Haplocanthosaurus remains were collected dates back to the Late Jurassic, about 155-152 million years ago.

It's a very exciting find because few specimens of Haplocanthosaurus exist. The first were also found in Colorado, in Garden Park near Canon City, by Carnegie Museum of Natural History paleontologists William H. Utterback and John Bell Hatcher in 1901. The type specimens (H. priscus and H. utterbacki) were described by Hatcher in 1903. The fossils were prepared under the direction of chief preparator, Arthur S. Coggeshall.

Mounted skeleton of Haplocanthosaurus delfsi: Cleveland Museum of Natural History
Mounted skeleton of Haplocanthosaurus delfsi: Cleveland Museum of Natural HistoryCourtesy ScottRobertAnselmo via Wikimedia Commons
Compared to its larger and heavier long-necked, small-headed cousins such as Apatosaurus and Diplodocus, the Haplocanthosaurus was a relatively small-sized sauropod dinosaur with a length of 35 to 40 feet and weighing maybe 14 tons. While most sauropods have hollow spaces in their backbones, a distinguishing characteristic of Haplocanthosaurus is the solidness of its vertebrae which Foster confirmed by doing a scan of the fossil bones at a local hospital in Grand Junction.

Haplocanthosaurus hindlimb: Science Museum of Minnesota
Haplocanthosaurus hindlimb: Science Museum of MinnesotaCourtesy Mark Ryan
The only mounted specimen of Haplocanthosaurus is the referred species (H. delphsi) on exhibit at the Cleveland Museum of Natural History in Ohio. No skull of the sauropod has ever been found so the head is just a fabricated guess. Other post-cranial remains exist, including some here at the Science Museum of Minnesota that were collected in Wyoming, but in general fossils of the dinosaur are rare. Material from only 10 individuals are known.

So far the Old Snowmass site has provided some vertebrae, ribs and a pelvis. but the landowners have been very accommodating in allowing the museum access to the dig site, and Foster hopes to find more Haplocanthosaurus bones - maybe even some skull material - in the coming summer season.

SOURCES and LINKS
Aspen Times story
More Haplocanthosaurus info
Osteology of Haplocanthosaurus by John Bell Hatcher
Jurrassic West: The Dinosaurs of the Morrison Formation and Their World by John Foster

Dec
09
2013

Charlie Darwin: The schoolbook victory in Texas obviously makes him feel like Charlie Sheen.
Charlie Darwin: The schoolbook victory in Texas obviously makes him feel like Charlie Sheen.Courtesy National Portrait Gallery
Last month, on November 22nd, while many people in the country were observing the 50th anniversary of president John F. Kennedy's assassination by shots fired from the Texas School Book Depository, there was another significant event happening that day involving Texas schoolbooks. That same Friday, despite objections and obstructionist tactics by creationists, the Texas Board of Education approved several public school science textbooks that included full coverage of evolution and climate change. The vote came late in the day and although the creationist faction did manage to make the adoption of two biology books contingent on a committee ruling regarding some alleged "flaws" in the text, the Texas Freedom Network (TFN), a watchdog group instrumental in countering the irrational creationist attacks, expects the passage to stand.

“It’s hard to overstate the importance of today’s vote, which is a huge win for science education and public school students in Texas,” said Kathy Miller, TFN's president. “Four years ago this board passed controversial curriculum standards some members hoped would force textbooks to water down instruction on evolution and climate change. But that strategy has failed because publishers refused to lie to students and parents demanded that their children get a 21st-century education based on established, mainstream science.”

SOURCES
Dallas Morning News story
Evolution is True article

Dec
06
2013

Victim of mass extinction: Will current species suffer a similar fate due to current environmental trends?
Victim of mass extinction: Will current species suffer a similar fate due to current environmental trends?Courtesy Mark Ryan
A new and troubling paper from the Committee on Understanding and Monitoring Abrupt Climate Change and its Impacts predicts possible and somewhat grim outcomes for some of Earth's natural systems from climate change that could rival the extinction event of the non-avian dinosaurs at the end of the Cretaceous Period 65 million years ago.

The abrupt impact could be coming faster than previously expected and would negatively affect human and physical climate systems as well. The document warns that the abruptness of the changes could be unanticipated and could find us unprepared to deal with them

Records of past climate preserved in tree rings, ice cores, and ocean sediments show that the atmosphere contains higher levels of carbon dioxide than it has in a very long time. Carbon emissions from human activity continue to add to this rising concentration. Other activities including deforestation and resource extraction place additional environmental pressures on our climate and other natural systems.

At the end of the Cretaceous, all species of non-avian dinosaurs, along with the megafauna of flying and swimming reptiles were wiped off the face of the Earth. Many dinosaur species showed signs of decline even before the Chicxlub asteroid delivered the final kibosh on their existence.

Dr. James W.C. White, a professor of Geological Sciences and of Environmental Studies at the University of Colorado at Boulder chaired the committee which included more than a dozen earth scientists and ocean researchers from universities in both Canada and the United States, and from the National Academy of Science.

A prepublication copy of the entire 201-page paper is available to read without charge on the National Academies Press page. You can also download it for free although it was a little tricky getting it to my computer.

SOURCE
MinnPost story

Nov
21
2013

3D printed dinosaur bone
3D printed dinosaur boneCourtesy Radiological Society of North America
Using state-of-the-art medical scanning and printing technology, German paleontologists have been able to scan and reconstruct a dinosaur vertebrae that survived a World War II bombing raid that left hundreds of fossils unidentified. Dug out of a clay pit south of Halberstadt, Germany in the early 20th century, the fossil was jacketed in plaster (for protection during transportation from the field) and stored in the basement of the Museum für Naturkunde in Berlin along with numerous other fossils from Halberstadt in southern Germany and another dig site in Tanzania. When the Allies made a bombing raid over Berlin during WWII, a portion of the museum was hit and collapsed, leaving the poorly labeled fossils in one big messy pile of plaster jackets and rubble. Museum workers sorted the jacketed fossils from the rubble but which fossil came from which dig? The labeled plaster jackets gave no clue.

Plateosaurus mount: Early postcard of a Plateosaurus skeleton seen in a museum in Stuttgart, Germany.
Plateosaurus mount: Early postcard of a Plateosaurus skeleton seen in a museum in Stuttgart, Germany.Courtesy Mark Ryan
Modern technology came to the rescue from technicians from the Department of Radiology at Charité Campus Mitte in Berlin. One of the jacketed fossils was first scanned with a CT (computed tomography) scanner - similar to those used to scan and diagnose medical patients. Because the radiation absorption (attenuation) of the fossil differs from that of the surrounding matrix - the rocky material in which the fossil is encased - making it easy to outline and create a digital copy of the fossil. The resulting image was compared to field drawings from the two expeditions and identified as a vertebrae of a Triassic Period prosauropod known as a Plateosaurus. The dataset was entered into a computer, cleaned up a bit, and then fed into a 3D printer where - layer by plastic layer - an exact replica of the hidden and unprepared fossil was "printed" in 3-dimensions.

CT scanning and 3D printing of fossils has been in use for a while now but this is a first time paleontologists have been able to identify and copy a dinosaur bone still encased in a matrix wrapped in a plaster field jacket.

In the past, this couldn't have been done without first cutting open the field jacket and spending long hours of detailed lab preparation - i.e. removing all the matrix from around the fossil. Making copies of fossils usually entails creating molds using rubber or something similar, then filling the void with plaster or other casting materials. Now with 3D printing technology, exact (or scaled) duplicates of important fossils can be created and shared with scientists or schools for study and comparison. The dataset of the scan can serve the same purpose.

Both the cost and size of the technology have been reduced in recent years, making it both affordable and portable for many museums. The following videos show the processes in action. Desktop scanning of dinosaur bones and the printing a dinosaur skull with a simple desktop 3D printer.

SOURCES and LINKS
Story on Science Daily
Live Science story

Oct
23
2013

With the announcement of the Ultimate Dinosaurs: Giants of Gondwana exhibit comming to the Science Museum of Minnesota, I was thinking back to all the questions I have had regarding dinosaurs. Tyrannosaurus rex: the Tyrant Lizard King on display at the Royal Tyrrell Museum in Drumheller, Alberta.
Tyrannosaurus rex: the Tyrant Lizard King on display at the Royal Tyrrell Museum in Drumheller, Alberta.Courtesy Mark Ryan

Questions like: "Who gets to name Dinosaurs?" "What is this dinosaur named after?" and "What does this name mean?". I thought that I'd take some time here to answer these questions.

Oct
14
2013

Typical Paleozoic fossils from Minnesota: This year's National Fossil Day theme is Paleozoic fossils. Minnesota Paleozoic rocks hold an abundance of such fossils dating from the Late Cambrian though the Late Ordovician Periods.
Typical Paleozoic fossils from Minnesota: This year's National Fossil Day theme is Paleozoic fossils. Minnesota Paleozoic rocks hold an abundance of such fossils dating from the Late Cambrian though the Late Ordovician Periods.Courtesy Mark Ryan
It's Earth Science Week and this year's celebration centers around maps and mapping and their importance in geology and other earth sciences. Then on Saturday, October 19th from 1-4pm, the Science Museum of Minnesota is celebrating National Fossil Day with some special fossil-related exhibits throughout the museum. This year's theme is Paleozoic life, which is exactly the types of fossils commonly found in the southern half of Minnesota. Unfortunately, the official National Fossil Day website is closed due to the US government shutdown that continues, but that shouldn't stop anyone from celebrating fossils. Join us Saturday for some fossil fun.

LINKS
OneGeology mapping webite
Minnesota Geological Survey maps
Fossil hunting in Lilydale (closed indefinitely due to a spring 2013 tragedy)
Collecting fossils in Minnesota

Oct
07
2013

Enrolled trilobite: The trilobite's strategy of rolling itself up into a ball for protection dates back to some of its earliest known ancestors in the fossil record. This fossil trilobite (Isotelus?) was found in Late Ordovician shale in St. Paul, Minnesota.
Enrolled trilobite: The trilobite's strategy of rolling itself up into a ball for protection dates back to some of its earliest known ancestors in the fossil record. This fossil trilobite (Isotelus?) was found in Late Ordovician shale in St. Paul, Minnesota.Courtesy Mark Ryan
A new study appearing in Biology Letters shows that trilobites - everyone's favorite prehistoric water bug - developed an effective survival strategy much earlier than previously thought.

Trilobite fossils from Early Cambrian rock formations in the Canadian Rockies and elsewhere lend evidence that some of the earliest trilobites used enrollment (i.e rolling themselves up into a ball like an armadillo) to protect themselves from predators or the environment. Trilobite fossils found here in Minnesota are several million years younger dating back to the Late Cambrian through Late Ordovician Periods (500 - 430 mya) and are often found enrolled. It was an effective survival strategy.

Trilobites were arthropods, which meant they possessed exoskeletons, segmented bodies and jointed appendages. Their closest extant relative is the horseshoe crab. Trilobite bodies - for the most part - were comprised of a head (cephalon) positioned on a body (thorax) that was divided into three lobes: essentially an axial dividing a left and right pleura, and a tail (pygidium). The mouth (hypostome) was located on the underside. It's thought that most early trilobites were predators and/or scavengers who spent their lives roaming the sea floors looking carcasses, detritus or living prey to feed upon. Most trilobites possessed complex eyes (although some were eyeless). Like other arthropods (e.g. today's lobsters), trilobites would outgrow their exoskeletons, discarding them (molting) as they grew in size or changed shape. Their newly exposed soft skin soon hardened into a new, tough, outer casing. Once hardened, their segmented exoskeletons (composed of calcium carbonate) were ventrally flexible, giving them the ability to roll up into a ball should they need sudden protection from whatever threatened them.

Some early trilobite forms from Middle Cambrian-aged fossils had been viewed as incapable of enrolling but the new research based on much older fossils found in mudstones in the Canadian Rockies in Jasper Park pushes back the origins of the strategy to some of the earliest trilobites to appear in the fossil record (Suborder Olenellus). These appeared 10-20 million years earlier at the very beginnings of the Cambrian Period and show evidence of having already developed the ability to enroll.

Trilobites in some form or another existed across a span of more than 270 million years, a very successful run by any measure. The enrollment strategy certainly contributed to their longevity. Although trilobites were already in decline, the last of their kind were wiped out in the great extinction event that marked the end of the Permian Period and the start of the Triassic. They weren't the only casualty of the extinction: nearly 90 percent of Earth's species were terminated along with them.

Even though trilobites are extinct (they died out in the Permian Mass Extinction along with around 90 percent of Earth's species) they were an extremely successful and adaptable life form. No wonder they remain today a favorite among fossil collectors.

SOURCE and LINKS
Paper at Biology Letters
Major Trilobite features
A Guide to the Orders of Trilobites