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Posts Tagged ‘fossil’

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Photo: Woody Hibbard, Flickr
Petrified Forest National Park reaches into the Painted Desert in Arizona, which boasts a colorful badlands ecosystem.

A former colleague of mine, a naturalized citizen originally from northern China, has a goal to visit all the national parks. He puts me to shame. I have visited so few. But after listening to this story from the environmental radio show Living on Earth, I know I would really like to see one national park — Arizona’s Petrified Forest.

“BOBBY BASCOMB: We continue our series on US public lands now with a trip to one of our more unusual National Parks. Arizona’s Petrified Forest National Park is full of wildlife, and the beautiful hiking trails that we’ve come to expect in our public lands.

“But what really sets it apart are the trees that died there. … The fossilized remains of those trees, logs more than 6 feet in diameter, are still there today, cast in stone. Here to explain more about the unique geological process that preserved the ancient trees is Sarah Herve, the acting chief of interpretation for the park. …

“SARAH HERVE: Petrified wood is a fossil. A lot of times people think that it’s something different than you know, any other kind of fossil … the remains of gigantic forests that were here during the Late Triassic. The logs … have been turned to stone by rapid burial.

“There’s silica in the materials that the trees were buried in and the cellular structure has been replaced by silica. There’s other minerals present, but the glassy mineral silica is really, really good at exchanging places with cellular material. …

“BASCOMB: The end result then, is you have these logs lying around that look exactly like trees, you can see the rings in them, the bark, the whole thing, but it’s stone. …

“HERVE: That wood is oftentimes what we call rainbow wood, because it’s very, very colorful. [When] you look on the inside, there’s all kinds of pinks and purples and blue colors, blacks, and it’s really just amazing. … If you can picture these logs when they were trees, they would be comparable to like the giant sequoias of California. …

“BASCOMB: What are scientists able to learn about the geology of the area and the trees themselves from studying this petrified wood? …

“HERVE: This part of northern Arizona was a much more tropical kind of environment. We were closer to the equator at that time, the continents were together to form Pangaea, there was quite a bit more water through this region. [That’s] based on looking at the different fossils that are found within these rocks and the rocks themselves. It’s thought that there was a tremendous river system that was running through this area. … Something on the same magnitude as like the Mississippi or the Amazon River. …

“It’s really hard to imagine [a] place so full of trees and crocodile-like animals running around and lots of amphibians, right. Those are some of the different fossils that we find. … Then we have, you know, incredible badland topography. So that’s what a lot of people, you know, call the Painted Desert. And it is very, very colorful, that’s why it gets that name. But those deposits are the remains of those ancient rivers. … The dinosaurs that we find at Petrified Forest, they’re generally pretty small. So we’re at a time way before all the big dinosaurs happened. …

“BASCOMB: I understand that you also have petroglyphs there, left over from early inhabitants of the area. …

“HERVE:  There’s a lot of petroglyphs or what we call rock art in the park. There’s [sometimes] animistic forms. So you’ll see things that look like different kinds of birds or things that look really obviously like deer, you know, or elk or pronghorn antelope, which are animals that still live in the park today. And then some of the forms are very, very strange, and really hard to interpret. Some of the petroglyphs are also considered what we call solstice markers, or solar calendars. And so they have light interactions with the sun during different times of the year. …

“BASCOMB: We have a lot of national parks in our country; we’re very lucky that way. Why should somebody visit this park as opposed to any other?

“HERVE: You know, what I hear from a lot of park visitors is, ‘Wow, we’re so glad we came here, we like this better than Grand Canyon!’ And that’s not a dig on Grand Canyon. But it’s always interesting to me to hear that because I think a lot of times people don’t realize right when they get off the interstate what they’re in for.”

More at Living on Earth, here.

Thinking about my friend who is visiting all the parks, I realize it’s not unusual for naturalized citizens to appreciate the wonder and variety of this great land more than some of us who are native born. Another former colleague, also originally from China, has been expressing his delight in America by running half-marathons around the country. He has already covered more than half the states and won’t stop until he has run in all 50.

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Art: Senckenberg
The discovery of one of the oldest penguin fossils in the world reveals higher diversity of early penguins than previously thought.

Whenever I am tempted to think that everything on the planet has been discovered, a new fossil turns up.

Melissa Breyer writes at TreeHugger that a recently unearthed penguin fossil is responsible for a small but significant adjustment to how we see our world.

“Along the Waipara River in New Zealand’s Canterbury region are sites rich in avian fossils, many of which were entombed in marine sand not long (relatively speaking) after the extinction of the dinosaurs.

“One of the more intriguing fossil finds there of late is that of a giant penguin discovered by ornithologist Dr. Gerald Mayr from the Senckenberg Society for Natural Research and a team of colleagues from New Zealand. The Waimanu penguin had a man-sized body length of 150 centimeters (5 feet) and … is among the oldest penguin fossils in the world.

“But what makes the Waimanu even more interesting is that the bones are significantly different from other penguin fossils from the same time period, revealing that the diversity of Paleocene penguins was higher than previously thought. …

” ‘This diversity indicates that the first representatives of penguins already arose during the age of dinosaurs.’ ” More here.

Pretty funny that in order to illustrate the size of the newly found penguin relative to a grown man, the Senckenberg Society put the man in a “penguin suit.”

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With every new discovery of fossils, it seems, the first appearance of life on Earth is earlier.

Maybe.

There is always controversy, and your belief about the earliest date may depend on just how hellish you think the Hadean period was, when asteroids bombarded the planet and life probably would have been impossible.

Nicholas Wade writes at the New York Times, “Geologists have discovered in Greenland evidence for ancient life in rocks that are 3.7 billion years old. The find, if confirmed, would make these fossils the oldest on Earth and may change scientific understanding of the origins of life.

“Experts are likely to debate whether the structures described in the new report were formed biologically or through natural processes. If biological, the great age of the fossils complicates the task of reconstructing the evolution of life from the chemicals naturally present on the early Earth. It leaves comparatively little time for evolution to have occurred and puts the process close to a time when Earth was being bombarded by destructive asteroids. …

“Certain features ‘are fairly credible hallmarks of microbial activity,’ Abigail C. Allwood of Caltech’s Jet Propulsion Laboratory wrote in a commentary accompanying the Nature article [by Allen P. Nutman et al.]. They have a few features that make them ‘interesting and possibly biological,’ she added in an email.

“Another expert in the early Earth’s environment, Tanja Bosak of M.I.T., said the structures do resemble modern stromatolites but their origin ‘will be hotly debated.’ …

“Dr. Nutman argues that life must therefore have originated even earlier, probably in the late Hadean stage of Earth’s history, which lasted from 4.65 billion years ago — when the planet formed from debris in orbit around the sun — to 4 billion years ago.

“But the Hadean was so called because of the hellish conditions thought to have prevailed, including cataclysmic meteorite impacts that boiled the oceans into steam and turned Earth’s surface into molten lava. The largest of these impacts, at 4.5 billion years ago, tore a piece from Earth that became the moon. It is difficult to see how life could have begun under such circumstances.”

Weigh in on the controversy here.

Photo: Allen Nutman
Stromatolites from Greenland may be evidence of the oldest life on earth.

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It’s amazing what mysterious creatures scientists find in the fossil records of life on our planet. Jonathan Webb describes one such creature at the BBC.

“A 430 million-year-old sea creature apparently dragged its offspring around on strings like kites — a baffling habit not seen anywhere else in the animal kingdom.

“Scientists who discovered the fossil have dubbed it the ‘kite runner.’ Ten capsules tethered to its back appear to contain juvenile progeny, all at different stages of development.

“Reported in the journal PNAS, the many-legged, eyeless, 1 centimeter [fossil] was dug up from a site in Herefordshire before being taken to Oxford and computerised. This process involved grinding away the specimen, slice by slice, and photographing each of those sections to assemble a 3D reconstruction. …

” ‘You take its anatomy, code it into a data set and then run probabilistic methods on it, which will tell you how likely it is that something evolved in a particular way,’ [David Legg, a palaeontologist from the Oxford University Museum of Natural History,] explained. …

” ‘Nothing is known today that attaches the young by threads to its upper surface,’ said co-author Derek Briggs, from Yale University. …

“It was the variety of shapes seen among the 10 tethered babies that Dr Legg found most convincing. ‘We see them develop and begin to resemble the adult form more and more, as they get bigger,’ he said. ‘I’m definitely convinced that that’s what they were.’ ”

More at the BBC, here.

Photo: D Briggs/D Siveter/ Sutton/D Legg
This tiny, eyeless fossil creature, unrelated to any living species, carried babies in capsules tethered to its back.

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“How did the turtle get its shell?” asks Carolyn Y. Johnson in the Globe.

“A group of scientists at Yale University and the Smithsonian Institution argue that a reptile fossil that has been gathering dust in museum collections is actually a turtle ancestor, and that its reduced number of ribs, distribution of muscles, and T-shaped ribs could help settle the question once and for all.

“In a paper published Thursday in the journal Current Biology, they unveil the argument that a 260 million-year-old creature called Eunotosaurus africanus was a turtle ancestor, hoping to help resolve a debate that has split the scientific community for decades. …

“The ink spilled so far has roughly divided the scientific community in two camps. On one side are those who believe that the turtle shell came about as external bony scales, similar to the ones found on armadillos or certain lizards, that eventually fused together with the reptile’s internal rib cage. On the other side are those who believe that reptiles’ ribs instead began to broaden until they eventually formed the bony protrusion that is the shell, mirroring the way that turtles develop in the egg.”

Which theory does the 260-million-year-old Eunotosaurus support? Read up.

“ ‘The results are pretty convincing; previously I was skeptical as to whether Eunotosaurus was a likely relative of turtles,’ [Kenneth Angielczyk, a paleobiologist from the Field Museum in Chicago], wrote in an e-mail. ‘But Tyler [Lyson]’s results make me think it is a plausible idea.’  ”

Scientists clearly have a lot of fun, but let me try a more Kipling-esque approach to the turtle question.

When the world was new, Oh, Best Beloved, the Turtle was a small, soft creature who played all day with other small, soft turtles on the banks of the great gray greasy Limpopo River all set about with Giant Eucalyptus Trees. He was timid. He was shy. He kept his distance from the great beasts of the jungle. But he was watchful, too, and he learned from what he saw. And so it happened, Oh, Best Beloved, that at the very day, hour, and minute that the Giant Python Rock Snake stretched out the stumpy nose of the Elephant’s Child, the Turtle felt a great fear come upon him. And he ran and rolled himself in the grease of the greasy Limpopo River all set about with Giant Eucalyptus Trees, raced to the most gigantic of the Giant Eucalyptus Trees, embedded his sticky self in the most gigantic of the Giant Eucalyptus Trees seeds, and there remained.

When he felt brave enough to stick his head out, he reported to all the small, soft turtles what he had seen. And thus the world gained not only a Turtle with a Shell, but the very first embedded reporter.

Photo: Luke Norton
This South African sideneck turtle bears a structural resemblance to the fossil of a creature called Eunotosaurus africanus.

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