Latest news with #MazonCreek
CBS News
6 days ago
- Science
- CBS News
Field Museum shows 300 million-plus-year-old fossils from Mazon Creek not far from Chicago
Those who know a lot about fossils are likely already familiar with the Mazon Creek fossil just outside Chicago. Those who don't know a lot about fossils and the Mazon Creek site? They soon will, thanks to the Field Museum of Natural History. You might remember years ago, the Field Museum had an interactive room called the Place for Wonder, where young kids could touch a taxidermy polar bear and listen to seashells. The Place for Wonder is not around anymore as you may remember it, but today's kids are still full of wide-eyed wonder at the Field Museum — particularly as they learn about the discoveries made at Mazon Creek. Joseph Goldfarb, 7, has a perfectly appropriate word to express his wonder. He repeatedly said, "Whoa!" as he saw the fossils from Mazon Creek. But what else can you say when you see something older than the dinosaurs — predating them by something on the order of 130 million years? Joseph was watching as Dr. Arjan Mann, the assistant curator for fossil fishes and early tetrapods at the Field Museum's Negaunee Integrative Research Center, held up an old, round rock called a concretion. Inside that rock was a fossil nearly 309 million years old. "An early amphibian relative called a temnospondyl. It is a new species from Mazon Creek," explained Mann. "If you were to just, you know, even as like an amateur, look at it, you would think that this is a little salamander in the rock." That temnospondyl is just one of many fossils found not far from home. "One of the greatest fossil localities in the world, right outside the Chicago area," said Mann. The Mazon Creek fossil site is less than two hours southwest of Chicago. The fossils were discovered in piles of rock and dirt left over from coal mining, and have become a treasure trove for fossil hunters. Mazon Creek is a tributary of the Illinois River. Strictly speaking, sources explain, Mazon Creek itself is one of several localities where fossils have been found called the Francis Creek Shale — with parts located in Grundy, Kankakee, LaSalle, Livingston, and Will counties. But the entire site is commonly called the Mazon Creek area, the Field Museum explained. Large-scale mining operations began in Mazon Creek in the mid-19th century, and event at that time, it became clear that there was more of interest at the site than coal, the Field Museum explained in a news release. The fossils at the site are so abundant and so well-preserved that researchers can reconstruct a detailed impression of the prehistoric ecosystem of which they were a part, the museum said. In addition to the aforementioned relative of the salamander, the fossils also preserve creatures such as squid-like cephalopods, sea scorpions, and a soft-bodied creature with a long snout and primitive eyes called the Tully monster, the Field Museum explained. "You go about just to every museum collection in the world, you can find Mazon Creek fossils," Mann said. "They're that abundant." Every spring and summer, amateur fossil hunters at Mazon Creek work alongside professional paleontologists like Dr. Mann and his team. "I mean, it's one of most fun things you can do, in my opinion, is go fossil collecting and dig in the dirt — and yeah, have fun," said Mann. Every ancient concretion the paleontologists crack open can teach us something new. "This is one of the more exciting things because it might be one of the missing links between what we know are modern amphibians like frogs, caecilians and salamanders and their Paleozoic relatives," said Mann. "That's a long paleontological evolutionary mystery." What else can you say to all that but, "Whoa?" Dr. Mann and his team have made about a dozen trips to Mazon Creek this summer. He says that ancient relative of the salamander, the temnospondyl, will be named for the people who found its fossil — a husband and wife who own a rock shop in Evanston.
Yahoo
27-05-2025
- Science
- Yahoo
The world's best-preserved fossils are right outside Chicago. But there are no dinosaur bones at Mazon Creek
CHICAGO — Sixty-five miles southwest of Chicago, a small hill that looks like a prop from an Indiana Jones movie breaks up the flat, monotone landscape. Consisting of shale, sandstone and rocks from an old coal mine, the waste pile — located on a massive river delta from another era — is an unremarkable remnant from the region's once-thriving coal industry. Except it contains many of the world's best-preserved, most diverse fossils. The defunct mine's location in Grundy County is one of several sites spanning six counties that belong to the Mazon Creek fossil beds, a time capsule dating back some 309 million years — way before the age of dinosaurs — to the Carboniferous period, when large coal deposits formed around the world and terrestrial ecosystems developed. At the time, this area was swampy and tropical, and home to various organisms like the Illinois state fossil, the peculiar Tully monster, which has been found only here — a cigar-shaped vertebrate creature up to a foot long with eyes that protruded sideways, a long snout and a toothy mouth. 'You get everything from insects, millipedes, plants, jellyfish, all the way to early tetrapods, big animals like embolomeri, as well as larval forms,' said Arjan Mann, who recently joined the museum as an assistant curator of fossil fishes and early tetrapods, or four-limbed animals, such as the crocodile-like and predatory embolomeri. 'This makes Mazon Creek the most complete record of a Paleozoic ecosystem' — an era that contained six periods and spanned from 541 million to 252 million years ago. Despite their uniqueness, these sites remain relatively unknown to many outside paleontology circles. Maybe because no dinosaur bones have ever been found in this area or the rest of Illinois, and those tend to draw the most attention. Even as the Field Museum celebrates on Friday 25 years since the arrival of famed Sue the T. rex to its halls after the bones were discovered in South Dakota, some scientists are shining a light on other creatures and plants that once roamed and grew in Illinois. Mann's role as a paleontologist, specifically at the Field Museum, was recently ranked the second-coolest job in the country on a survey. And he wants to make the science more accessible, regardless of age or expertise, by collaborating with amateur fossil collectors from the Earth Science Club of Northern Illinois to find new specimens. The club and museum take amateur fossil hunters to Mazon Creek sites on public land like state parks, where permits are required, as well as on private property like the Grundy County site they recently visited where they have an established relationship with the landowners. In 1946, the museum hired Eugene Richardson as curator of fossil invertebrates, and he became a strong advocate for collaborating with amateur fossil collectors in Mazon Creek localities. Since Richardson's death in 1983, paleontological research at the institution has skewed toward dinosaurs, Mann said. Now, he wants to renew the museum's focus on Mazon Creek. 'I did my dissertation entirely on this site, even though I'm from Canada,' Mann said. 'So my love for this site and my knowledge of what it was in the past, gives me a drive to want to revitalize both the scientific research to show how important the locality is, (and) how important it is as a social experiment — and how we can involve people at all levels.' Rich Holm, a software engineer, joined the club about 20 years ago with his daughter, Anna. While picking through the pea gravel in their Naperville backyard, she'd found tiny fossils of a now-extinct, horn-shaped coral and a brachiopod — a marine animal that resembles a clam. A visit to a gift shop that sold stones and crystals solidified Anna's interest and she told Holm she wanted to collect rocks. 'I said, 'Sure, that's fine,'' he recalled. Which is how he ended up on the club's website and began taking her to junior group outings. 'Now I'm on the board of directors.' Holm said the paleontology experiences fostered a love for science in Anna, who went on to study microbiology in college. Sometimes she'll join him on one of his 20 to 40 yearly collecting field trips. On one trip, he found a fossilized Paleocampa anthrax , a rare, extinct worm with bristles that make it look like a caterpillar and is related to modern-day fireworms. He has also found a fossilized tailless whip scorpion, of the extinct species Graeophonus carbonatius; arachnids like this are rare and coveted among collectors. But acquiring rare specimens requires patience and identifying a lot of concretions, or mineral masses that sometimes contain fossils. The shape of a concretion generally offers a clue into what's inside, so collectors want to bring back as many as possible to open, Holm said. At the recent Mazon Creek dig, participants used pickaxes to sift through the waste pile, known as a spoil tip. 'Can I give you some of the stuff in my pocket?' Mann asked a colleague as he stood on top of the spoil tip. 'It's weighing me down.' In a comical scene, he started pulling out rock after rock. 'You just keep getting them,' Mann laughed. 'And it's like a second collection experience when you open them,' he said. 'These act as little time capsules that entomb animals within them.' Holm has found so many fossils that he often gives them away to family, friends and even co-workers, who proudly display the gifts on their desks. 'You can get buried' in a collection, he joked. 'So I give them away quite readily.' While some prefer to crack the concretions with a hammer for faster results, this can damage the fossil inside. Experts suggest opening the Mazon Creek stones by alternately freezing and thawing them in water. As the liquid freezes and expands, it gently cracks the rocks open by putting pressure on their weakest points. This method often requires that collectors' families make room for the fossils at home. 'It's a passion that just grows exponentially,' Holm said. 'So, probably very soon after you start, you need a freezer of your own.' For Father's Day one year, Holm's wife gave him one that he put in his basement. It is always stacked full of containers with concretions from different sites. 'It can sometimes take six months to a year for some to open,' Holm said. 'I go down there almost every other day, and I'm constantly cycling the containers and checking. So that's where the treasure hunt can continue all year round.' Participants in the Grundy County fossil hunt are still in the freeze-thaw stage for the concretions they found that day. Jeff Allen, another member of the club, uses half of the freezer in his basement to store his frozen fossils. 'I have a very patient wife,' he chuckled. 'That's the kind of enthusiasm that these collectors have,' Mann said. 'As the Field Museum, we would never be able to do the kind of operation that we're able to accomplish involving local collectors who are doing this work, and having good relationships with them.' Mann and a colleague have set out to find the missing stage between the anatomies of primitive amphibians and modern ones, hoping the fossils in the 309 million-year-old Mazon Creek hold the answer. Some modern amphibians have long had body characteristics that make them easily recognizable: frogs with powerful hind legs and salamanders with forelimbs and long tails. Less universally familiar but still peculiar is another kind of amphibian that's still around today, the so-called caecilians, which have long, legless, snake-like bodies and spend most of their lives underground. 'But the thing is, if you go back into the fossil record, you basically see them maintaining the same body plan for about 250 million years. And before that, we have nothing,' said Cal So, a postdoctoral scientist at the museum who specializes in amphibians. 'This time period essentially provides a really good place to look for what some of these early relatives of amphibians looked like. That's one of the biggest mysteries in paleontology — evolutionary biology in general.' The fossils in Mazon Creek offer a snapshot in time from hundreds of millions of years ago, when high oxygen levels, coal deposits and rapid burial caused many plants and animals, including soft tissues, to be well-preserved. Mann looked toward the top of the waste pile. 'When you go up, it's like you're going back in time,' he said. 'When you see topology like this, rounded hills are probably spoil piles. And if you dig into these, there's a good chance you're going to find a concretion.' The Mazon Creek fossil beds include a variety of sites, including local mine spoil piles, no-dig zones like the Mazonia-Braidwood State Fish and Wildlife Area, which requires a permit, and other localities that require sifting through rocks and silt on riverbeds and riverbanks, or bushwhacking through overgrown vegetation. Fossils in the state are not just limited to this one area. Paleontologists also visit Danville and surrounding areas in east central Illinois, and the Little Egypt region around Cairo in far southern Illinois. 'This geologic history is really all over Illinois. And Mazon Creek could be a gateway into that for people,' Mann said. 'That's really what this locality is about. It's about the intersection between private collectors, amateur paleontologists and professionals, and working together synergistically to unveil the natural history data here — and getting kids hooked on fossils when they're young.' ____
