Stories tagged geology

Literally dig deeper into the earth surface and discover what is lying right under your feet.

Mount Etna, located on the Italian island of Sicily, has been very active lately, as seen in this spectacular video by Boris Behncke, a researcher with Italy's National Institute of Geophysics and Volcanology. The stratovolcano is formed along the northern boundary of the African Plate as it collides with the Eurasian Plate. The shots of the exploding lava bubbles are fantastic and are reminiscent of a Fourth of July fireworks display. The images with the setting Moon are serenely beautiful. Etna is also blowing some great smoke rings!

In other volcano news, the rumblings of a new volcano have been detected under a half-mile thick sheet of ice in West Antarctica. Using seismograph data gathered from several field sites across Antarctica researchers - led by Prof. Doug Weins and PhD student Amanda Lough of Washington University in St. Louis, Missouri - think the volcano could be the newest in a chain of volcanos migrating under the ice-covered continent. Radar images gathered by researchers from the University of Texas have confirmed volcanic ash encased in the ice near the source of the detected activity. The seismic rumblings originate somewhere between 6 and 9 miles beneath the bedrock surface, too deep to be caused by sub-surface glacial movement or even tectonic activity. The study appears in the advanced online issue of Nature Geoscience.

SOURCE
Science Daily story

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

Kristi Curry Rogers: turned her childhood passion for dinosaurs into a career as a vertebrate paleontologist. She's seen here talking about her work with titanosaurs to the Geological Society of Minnesota.
Kristi Curry Rogers: turned her childhood passion for dinosaurs into a career as a vertebrate paleontologist. She's seen here talking about her work with titanosaurs to the Geological Society of Minnesota.Courtesy Mark Ryan
Are you like me? Has your passion for paleontology remained with you beyond your childhood fascination with dinosaurs and fossils? Do you still yearn to become a paleontologist and uncover the next great sauropod discovery or rare trilobite fossil? Paleontology's not a particularly easy field to get into - and the jobs aren't as numerous as you'd hope - but it can be done. Amy Atwater is a blogger and paleontology intern (like me!) and lists ten things you can do to fulfill your paleo aspirations. Her advice is aimed more toward the female side of the gender spectrum (her column is part of the Huffington Post's Girls in STEM series) but her tips are useful to just about anyone who wishes to pursue a career in the fascinating science of fossils and ancient life.

More about STEM

Sep
16
2013

Fossil of Hallucigenia in Burgess Shale
Fossil of Hallucigenia in Burgess ShaleCourtesy ap2il via Flickr
One of the strangest creatures to emerge from the famed Burgess Shale in the mountains of British Columbia, is the rightly named Hallucigenia, a strange spiky, wormlike creature that once scuttled across the Cambrian sea bottom more than 500 million years ago. Originally considered a totally unique (and baffling) creature, Hallucigenia has now been linked to other similar-aged wormlike creatures found around the world.

Hallucigenia first came to light in 1909 after Charles Doolitle Walcott, an expert in trilobites and secretary of the Smithsonian Institute, discovered a Lagerstätte in the mountains of British Columbia that was unlike any other found before.

Location of Walcott Quarry as seen from Field, BC
Location of Walcott Quarry as seen from Field, BCCourtesy Mark Ryan
Located in Yoho National Park on a steep slope between Mount Field and Wapta peak above the railroad town of Field, B.C., Walcott's quarry produced some of the strangest creatures - many of them soft-bodied and rarely found in the fossil record. The rock section, previously known as the Stephens Formation became known as the Burgess Shale, after nearby Burgess Pass. In the years following the discovery, Walcott and other scientists studied the strange fossils in an effort to decipher them and the environment in which they had lived and died.

Because of the high degree of preservation, the creatures that made the fossils were most likely buried suddenly in some sort of giant underwater mudslide that quickly entombed an entire marine community in an anoxic environment where decomposition was stifled. A perfect environment for preserving the soft-bodied tissue.

Display model of Hallucigenia: Royal Tyrrell Museum in Drumheller, Alberta
Display model of Hallucigenia: Royal Tyrrell Museum in Drumheller, AlbertaCourtesy Mark Ryan
Some of the Burgess Shale denizens appeared to be of completely new and unknown phyla with bizarre and unfamiliar body plans and no known descendents in the modern age. Hallucigenia certainly led the pack in this department. The tiny strangely constructed worm was only about an inch in length and confounded Walcott and other scientists for more than a century. They couldn''t even say for sure which side was up or down. Early Hallucigenia fossils showed a row of seven tentacles along one side. The opposite side contained seven sets of stiff spikes that were interpreted to be legs. A truly bizarre, aptly named freak-show creature that would be right at home in your average nightmare.

New evidence can often turn an old idea on its ear - or in this case, on its back. Recent scrutiny of newer, better-defined Hallucigenia fossils has revealed another set of "tentacles", leading scientist to realize they had Hallucigenia all flipped around. What they once thought was its top side was actually its bottom. Its dorsal "tentacles" were actually its legs. And its spiky "legs" belonged on its back, probably to serve as protection against predators.

This information along with a new study published in Proceedings of the Royal Society B now places Hallucigenia within a group of other worm-like creatures whose fossils are found around the world, including China, Canada, Great Britain, and Australia. It also links it to a living group - Onychophora - the velvet worms that mostly inhabit the tropical forests of the Southern Hemisphere.

"They may not be exactly the same species, but they are all probably related to the same group of worm-like creature that we call lobopods," said Dr. Jean-Bernard Caron, curator of invertebrate paleontology at the Royal Ontario Museum and the study's lead researcher. Caron is an expert in Burgess Shale fossils and his study of Hallucigenia and other fossils from the formation continues to glean new knowledge about the strange creatures that existed in the so-called Cambrian Explosion. Check out Caron's Burgess Shale website. It's full of great information about the quarry and the incredible fossils found there.

Burgess Shale location: Walcott Quarry sets on steep slope in valley between Mt. Wapta and Mt. Field.
Burgess Shale location: Walcott Quarry sets on steep slope in valley between Mt. Wapta and Mt. Field.Courtesy Mark Ryan
Walcott's Burgess Shale quarry has been designated a World Heritage site. The only way to visit it (or the fossil fields on nearby Mt. Stephen) is through guided hikes led by either Parks Canada or The Burgess Shale Geoscience Foundation. The 10 hour round-trip hike (rated moderate to difficult) takes participants up 2500 feet in elevation to Mt. Fields and requires reservations and a deposit. Fossil collecting is prohibited but the views are said to be spectacular.
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SOURCE and LINKS
The Province story
The Burgess Shale at Smithsonian website
Dr. Caron's Burgess Shale website
Parks Canada Burgess Shale info

Microbes: Some have been found surviving deep beneath the ocean floor.
Microbes: Some have been found surviving deep beneath the ocean floor.Courtesy EMSL
Microbes found living in rocks 1.5 miles under the ocean floor live such slow-paced lives that they reproduce only every 10,000 years or so. That's a long time between generations. They live this way in rocks estimated to be 100 million years old. The discovery was announced by scientists from the Integrated Ocean Drilling Program at a meeting of geochemists at the Goldschmidt onference in Florence, Italy. Scientists have also discovered other life forms - viruses and fungi - living zombie-like existences in the same deep rock layers.

Dr Beth Orcutt of Bigelow Laboratory for Ocean Sciences in Maine wonders how life exists in such extreme environments and where Earth's biosphere actually terminates.
"The deeper we look, the deeper we are still finding cells," she said, "and the discussion now is where is the limit? Is it going to be depth, is it going to be temperature? Where is the limit from there being life to there being no life?"
The density of the microbial population living in the deep rocks is miniscule compared to those found at the surface, but scientists still wonder if the microbes can actually be changing the lithosphere through chemical reaction with carbon and other elements in the rocks, and what results from that interaction.

SOURCE and LINKS
BBC Science-Environment news
Integrated Ocean Drilling Program page
Goldschmidt conference page
Bigelow Laboratory for Ocean Sciences page

For a long time, scientists have known a major volcano complex was under the Pacific Ocean off the coast of Japan. But upon further inspection, they've discovered it's one huge volcano, measuring 280 miles by 400 miles across. You can read more about this huge discovery right here.

Jul
24
2013

Green River Formation slab: The head end of Lepisosteus has been partially prepared.The rest of the fossil is hidden beneath a layer of rock matrix.
Green River Formation slab: The head end of Lepisosteus has been partially prepared.The rest of the fossil is hidden beneath a layer of rock matrix.Courtesy Mark Ryan
I've had the great fortune of being able to volunteer in the paleontology lab at the Science Museum of Minnesota. I'm in my fourth month there and it's been a real blast. My first project was preparing (cleaning) the skull of a small oreodont collected from the White River Formation in Wyoming. This is the same formation exposed in the fossil-rich South Dakota Badlands. By cleaning, I mean removing all the rock (matrix) in which the skull is encased. I've also helped patch up the casts of a couple of lambeosaurus skulls, and spent a few days puzzling over a crocodile skull reduced to about 1000 pieces.

Removing matrix: Science Museum of Minnesota fossil preparator Becky Huset uses an air scribe to methodically remove the thin rock veneer covering the remains of Lepisosteus, a fossil gar.
Removing matrix: Science Museum of Minnesota fossil preparator Becky Huset uses an air scribe to methodically remove the thin rock veneer covering the remains of Lepisosteus, a fossil gar.Courtesy Mark Ryan
At the moment, preparators been working on the remains of a 52 million year-old gar collected from the Green River Formation in southwestern Wyoming. Most of the work is being done by the more experienced volunteers in the lab but I've been able to help a little, taking my turn with the air scribe to reveal some caudal scales in their rocky grave. This particular specimen, an ancient member of Lepisosteus, was collected in Lincoln County, Wyoming. It's fascinating work uncovering something that last saw sunlight more than 50 million years ago. Now, at least, its remains can bask in the glare of the paleo lab's artificial lights.

Lepisosteus tail comes to light: SMM paleo lab technician, Kay Blair, works at revealing the 52 million year-old gar's tail rays and posterior scales.
Lepisosteus tail comes to light: SMM paleo lab technician, Kay Blair, works at revealing the 52 million year-old gar's tail rays and posterior scales.Courtesy Mark Ryan
Fifty some million years ago, the gar lived in a large body of water known as Fossil Lake, one of three intermountain lakes that existed at different times in a sub-tropical environment in that part of Wyoming. The intermountain basin in and around the lake teemed with both floral and faunal life that over about 4000 years lived and died and were fossilized forming one of the great Lagerstätten in the world. The surrounding mountains were composed mainly of limestone, and the rivers and streams eroding those mountains carried high levels of calcite (CaC3) into the lake, resulting in a high sedimentation rate that added to the ideal fossilization environment.

(More about the Green River lakes and fossils in previous Buzz story).

Most of the fossils coming out of the Fossil Lake strata have been fossilized by a process called permineralization, where mineral-rich water permeates all the spaces and pores in the skeleton and the minerals (in this case calcite) crystallize out of the water replacing bone material down to the cellular level. Some carbonization is also involved. This process depletes the remains of volatiles and is caused by the heat and pressure of sediment compression, which also crushes and flattens the fossils, and tends to color them either brown or black.

Scattered bones: The fossil gar's head was blown apart by gases that built up during its decomposition.
Scattered bones: The fossil gar's head was blown apart by gases that built up during its decomposition.Courtesy Mark Ryan
That's very apparent with our gar. Although only portions of the fish's remains have been exhumed (its head and tail) the fossil is already providing some information about what followed the gar's death (taphonomy). Lepisosteus favored the shallow, swampy edges of Fossil Lake and when it died it probably floated on the surface for a while giving bacteria time to enter its mouth and gills and begin their decomposition work before the corpse was buried beneath sediments.

We can deduce this scenario by the manner the remains are preserved. The bones of the gar's skull and jaws are scattered and jumbled in a mish-mash of bones and scales. The head appears to have been blown apart, and that's probably what happened. As the microbes feasted on the fish's head, they released gases inside the corpse which built up, and bloated the gar to a point where it burst from the internal pressure. The mandibles, the cranium, and other bones broke apart before settling to the bottom and are disarticulated. The very end of the tail, however, shows no such disruption. The rays of the caudal fins looking almost as fresh as they did when the gar died half a million centuries ago.

Scales as tough as nails: In life, an enamel-like tissue called ganoin made the diamond-shaped scales of Lepisosteus tough and predator-resistant.
Scales as tough as nails: In life, an enamel-like tissue called ganoin made the diamond-shaped scales of Lepisosteus tough and predator-resistant.Courtesy Mark Ryan
The scales of its mid-section are beginning to come to light. These diamond-shaped structures were covered with ganoin, an enamel-like tissue containing less than five percent organic material. The mineralized tissue gave Lepisosteus a very tough, predator-resistant exterior when it was alive but not so resistant to the bacteria that attacked the gar from the inside after it died. Preliminary work of the mid-section is showing signs of decomposition there but further work required.

One of the major experts on the fossils found in the Green River Formation is Lance Grande, a graduate of the University of Minnesota (and elsewhere) who has been working at Chicago's Field Museum for the past few decades. In the early '80s, Dr. Grande wrote a hefty bulletin titled Paleontology of the Green River Formation for the Wyoming Geological Survey, and has now come out with a new book titled The Lost World of Fossil Lake: Snapshots from Deep Time. In a recent television interview, Dr. Grande talked about his book and about the fossils found in the Green River Formation.

Hundreds of thousands of finely preserved fossils from Fossil Lake deposits can be found in museum displays and on rock shop shelves world-wide. The best fossils were buried quickly and preserved in near pristine condition. Many of these come from what used to be the deep center of the lake where conditions were probably anoxic and burial fairly swift. At times during Fossil Lake's history events like seasonal algal blooms or rapid turnovers of the water column occurred and caused massive die-offs of fishes. Other fish, like our gar, probably just died a regular death.

Progress so far: After several weeks of preparation, the remains of Lepisosteus are becoming more defined.
Progress so far: After several weeks of preparation, the remains of Lepisosteus are becoming more defined.Courtesy Mark Ryan
Every fossil tells a story, and our gar is no exception. Back in the Eocene epoch it lived for a short time in the then subtropic environment of southwest Wyoming, doing what gars do before it finally died along the shores of Fossil Lake. After it was buried, it was fossilized, dug up, and transferred to the collections vault of the Science Museum of Minnesota. A few months ago, it was retrieved from the vault and brought into the paleo lab where it's been worked on each week by several people. Whatever the gar was thinking when it was alive back in the late Eocene, you can be sure it was unaware that its post-mortem life would provide hours of detailed work, study and fascination for another curious life-form 52 million years later.

SOURCES AND LINKS

Green River Fossil Adventures
Fossil Butte National Monument
More about Green River Formation at Fossil News
The Green River Formation: A Fossil Fiesta
Green River Info at UCMP Berkeley

Brachiopod fossil in limestone matrix: Typical fossil found in the quarries at Lilydale and elsewhere in southern Minnesota.
Brachiopod fossil in limestone matrix: Typical fossil found in the quarries at Lilydale and elsewhere in southern Minnesota.Courtesy Mark Ryan
In response to last week's tragedy at the fossil quarries in Lilydale Regional Park, science writer Anne Brataas has written about the importance of continuing the practice of taking field trips outside the classroom, despite the inherent dangers real life can present.

Brataas is the CEO and founder of The Story Laboratory, LLC, as well as an instructional designer and science historian.

SOURCE
MinnPost article

John Wesley Powell: The Ute Indians called him Kapurats, meaning "arm off".
John Wesley Powell: The Ute Indians called him Kapurats, meaning "arm off".Courtesy Public domain via the National Park Service
A remarkable figure in the history of American science, John Wesley Powell was born this day in 1834 in Mount Morris, New York.

During the late 1860s and early 1870s, and despite losing his right arm during the Civil War, Powell led several extensive expeditions into the rugged, unexplored regions of the American West collecting geological, geographical, and ethnological data, along with natural history specimens for the United States government. A fervent scientist, Powell served as director of both the U.S. Geological Society and the Bureau of Ethnology, and helped found the National Geographic Society.

Powell is probably best remembered for his study and befriending of the Ute people, and for making the first explorations of the Colorado River (then called the Grand River) and the Grand Canyon. Lake Powell, a large reservoir located on the border of northern Arizona and southern Utah is named in his honor.

LINKS
NPS-USG Powell Info page
Powell Chronology
J.W. Powell Wikipedia page
More about Powell
Powell Expedition photos