Rhino in Stone

Preserving fossils involves gently covering them with new sediment, like packing fragile items when moving. You need to be careful and add cushiony layers to protect them. Surprisingly, volcanic activity can also help preserve fossils in certain conditions. Here are some examples of how volcanoes have managed to preserve amazing fossils.

Let's explore the amazing Ashfall Fossil Beds in Nebraska, a site that is around 12 million years old. Excavations at the site have revealed many fossil skeletons of animals like rhinos, camels, and tortoises, all preserved in volcanic ash. Surprisingly, the ash didn't come from Nebraska, but from a volcanic eruption 1,600 kilometers away in present-day Idaho. It's fascinating to see how these ancient animals were preserved in such a unique way!

There was a volcanic eruption about 12 million years ago that produced a lot of ash, which spread across the continent. This ash fell on a watering hole that was home to many animals. Unfortunately, the ash didn't just bury them, it also caused their deaths. Volcanic ash is dangerous because the particles are so fine that animals can inhale them, causing harm to their lungs. This event is known as the Bruneau-Jarbidge eruption, part of the same volcanic system as Yellowstone today.

Some fossilized bones have frothy-looking growths linked to respiratory issues, showing the animals died from inhaling toxic substances. By looking at the layers, we can determine the order of their deaths. Smaller animals like birds and turtles are buried deepest, followed by medium-sized animals like horses and camels, and finally the largest animals like rhinos at the top. It's fascinating to learn there were rhinos and camels living in North America in the past!

Ashfall has over a hundred rhino skeletons that were preserved in great detail. The ash, while deadly to living animals, created a soft bed for their remains. Some skeletons are in three-dimensional form, just like when the animals were alive. Impressions of birds' feathers can also be seen in the ashes. This natural disaster from 12 million years ago is now a valuable resource for scientists studying ancient ecosystems in North America.

Volcanic ash is great at preserving bodies and other things like footprints. The Laetoli Footprints in Tanzania are famous because they were preserved in 3.6 million year old ash deposits. Many animal footprints have been found there, including those of elephants, giraffes, birds, and insects. But what's really cool is that there are also footprints that look like they were made by human ancestors, possibly Australopithecus afarensis, the same species as Lucy. The footprints show at least three individuals walking together or at similar times. One even stepped into the footprints of the others. It's fascinating to see how our ancestors walked!

Back when these footprints were discovered, we weren't entirely sure how our ancestors walked - on two legs like us or using their knuckles like chimpanzees. Finding footprints without knuckle-prints was a big deal and helped answer a key question in human origins research. The Laetoli footprint site is like a layered cake of preserved trackways. The Sadiman volcano, located 20 kilometers away, would erupt ash that turned into sticky mud from rainfall. Our ancestors and other animals walked on this sticky mud and left footprints that hardened into stone. Eruptions later covered and protected these footprints. Millions of years later, erosion exposed the footprint layers, revealing a fascinating piece of human history.

The ash beds hold valuable ancient information but they are delicate. They can easily be damaged by rain, plant roots, or even the feet of modern animals. To protect these fragile pieces of history, researchers cover them with layers of soil and sand when not studying them. In this case, erosion can both reveal and conceal important discoveries.

Let's talk about fossils that formed near a volcanic eruption. When you're close to an eruption, you have to watch out for pyroclastic flows, which are superheated avalanches of ash, gas, and rock. These flows can be over 800 degrees Celsius and move quickly, so it's best to stay out of their path. Although pyroclastic flows usually destroy everything, sometimes they can preserve cool fossils. When they cool down, these flows create ignimbrite deposits, similar to pumice stone.

In Rome, scientists found a surprising discovery in a 29,000-year-old ignimbrite deposit. They CT-scanned rocks from the deposit and saw the impression of a vulture's head, preserved in stunning detail. The pyroclastic flow had engulfed the vulture, preserving its features like its tongue, eyeballs, and even a transparent eyelid. This type of preservation is similar to what happened in Pompeii, but with even more detail. The pyroclastic flow that hit the vulture had cooled to under 100 degrees Celsius, allowing soft tissues to be preserved within the ash. It's a fascinating find that offers a unique glimpse into the past.

So, you might be thinking that fossils can't be preserved in lava, right? Well, let me tell you about the Blue Lake Rhino in Washington. In a cave formed from ancient lava, people found fossil rhino bones in the early 1900s. And the cave itself looked suspiciously like a rhino. Turns out, it's actually an impression of a rhino's body preserved by flowing lava. The rock in this site, called pillow basalt, forms when lava cools quickly in water. Around 15 million years ago, lava flowed into the water, surrounded the rhino, and turned into solid basalt. After the rhino's soft tissue rotted away, it left behind a rhino-shaped hole. Pretty cool, right?

Good news for the rhino! Researchers believe it was already dead when it got covered in lava. It might have just been floating in the water until the lava came. Nearby caves shaped like logs suggest they were made when lava hit floating trees. This rhino's unique burial is one of the coolest ways to be preserved. We've seen body fossils in ash and lava, and even footprints in ash so far.

Get ready to see dinosaur footprints preserved in magma! In the Jindong Formation in South Korea, there is a layer of igneous rock from the Cretaceous Period that has footprints from sauropods, like the Brontosaurus. Some footprints are as long as three feet. There are also footprints preserved in ash, but the magma footprints are the most exciting find. It might sound strange to see footprints in magma, but it's definitely a unique discovery worth checking out.

Animals can't walk on molten rock because they'd burn their feet. And I actually said magma, not lava. Remember, lava is on the surface, and magma is underground. Different environments mean different types of rock formations. These dinosaur footprints are preserved in sill rock, which forms underground from magma flow. So, these rocks formed underground!

No, we don't believe these dinosaurs were walking in lava. Here's what we think really happened at the site based on the geology. The dinosaurs walked across mud, leaving footprints behind. The footprints were covered and filled in with fresher mud quickly, preserving a lot of detail. Over time, the mud layers turned into rock. The lower rock layer holds the actual footprints on its upper surface, while the upper layer has natural molds of those footprints. Magma seeped in between the mudstone layers and shaped around the casts of the footprints. The magma cooled and hardened, preserving the shape of the original footprints on the upper surface of the sill. The mudstone eroded away, but the sill remained and exposed these interesting magma footprints. Even though they are magma copies, they are preserved in great detail, showing the toes and claws of the dinosaur's feet. So there you have it, magma tracks!

There are times when volcanoes have actually saved things from being lost forever. Researchers find this very exciting, even though it may have been unfortunate for the animals involved. The Blue Lake rhino, however, was already deceased, so it didn't really mind.