Stories tagged geology

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

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

Fifty years ago, on March 27, 1964 at 5:36pm local time, a huge, magnitude 9.2 earthquake rattled the state of Alaska. The quake's epicenter was located about 75 miles east of Anchorage, at a depth of 15 miles. Violent shaking lasted about 4 minutes and triggered several avalanches and landslides, and caused damage to many of Alaska's major cities including Anchorage. Quake-generated tsunamis caused additional damage. A 30-ft wave destroyed Kodiak, Alaska's ocean-front industries and much of the city's fishing fleet.

Despite it being the 2nd largest earthquake ever recorded (a 1960 Chinese quake measured magnitude 9.5), Alaska's Good Friday quake and resulting tsunami caused only 131 deaths (115 in Alaska; 16 in Oregon and California!).

As noted in the video at the top of the page, the Alaska earthquake took place just as plate tectonics was gaining acceptance in the scientific community. The idea of moving and colliding crustal plates had been around since the early 1920s but didn't gain any serious foothold until the 1960s. The developing theory helped explain the 1964 Great Alaska Earthquake, which was the result of subduction of the Pacific plate beneath the North American plate.

More scientific information can be found here and here.

The video below show some of the quake's effects in Anchorage and elsewhere.

This BBC documentary produced a few years back provides some valuable insight and information involving some of the dinosaurs included in the Science Museum of Minnesota's new upcoming exhibit Ultimate Dinosaurs which opens March 1.

TCharles Darwin
Charles DarwinCourtesy Mark Ryan
oday marks the 205th anniversary of the birth of geologist and naturalist Charles Darwin. Born in 1809 in Shrewsbury, Shropshire, England, Darwin revolutionized the world of science with 1859 publication of On the Origin of Species. You can learn more about him here and here.


A brief and nifty refresher video on plate tectonics and plate boundaries to help finish up the year.

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