12 Days of Inkfish, Day 6: Zion Canyon

Stories about earth science have all the transformations and power struggles of a fairy tale. When I asked my friend Tyler Auer—a photography blogger who studied geoscience in college—to tell me the story behind a favorite photo, he sent me a tale that’s part Princess and the Pea and part Jurassic Park.

Tyler took this picture at Zion Canyon, one of the many national park areas (including the Grand Canyon) within the 130,000-square-mile formation known as the Colorado Plateau.

“Around the time the dinosaurs roamed the western US, the Colorado plateau was a giant sea of sand dunes,” Tyler says. Over millions of years, these sand dunes kept forming on top of one another and compressing into layered sandstone. You can see the outlines of the ancient dunes, like so many stacked mattresses, in the striations of the canyon walls.

While the sand dunes were turning to rock, they were also being pushed upward by tectonic activity. Cracks formed in the ground like the crust of a bread loaf in the oven. Zion Canyon began as one of these cracks. But “sandstone is really soft, as far as rocks go,” Tyler says, “and running water carves through it quickly.” Rainwater and the flow of the Virgin River gradually deepened this split into a half-mile chasm with almost vertical walls.

Since the Colorado Plateau may be the thickest sandstone layer that’s ever formed, it's provided nature with a deep toolkit. “The Colorado Plateau is magnificent example of the slow but beautiful work nature can do,” Tyler says. You can find more fairy-tale pictures at his blog.

Image: Virgin River Narrows north of Zion Canyon, by Tyler Auer

Fossil Scan Reveals Ghost of Lizard Past

Peering into the past life of this fossil took an x-ray scanner powered by a particle accelerator. What scientists saw there was mysterious: an ancient lizard had left behind its skin and teeth, but none of its bones. To tell the ghost's tale, they relied on some very modern equipment.

At Stanford University, an accelerator called a synchrotron sends electrons zipping around a track fast enough that x-rays spin off of them. These x-rays are collected into an extremely bright x-ray beam that scientists can use for various projects. One application, x-ray fluorescence, lets researchers map the actual chemical elements inside on object.

Other methods of analyzing an item's chemical makeup require scientists to focus on tiny slices, destroy their samples entirely, or creep along at a rate of one square centimeter a day. But the setup at Stanford lets scientists look quickly and thoroughly at larger objects while keeping them in one piece. The synchrotron has previously been used to reveal writings of Archimedes that were scraped away and painted over, and to deduce the pattern on the feathers of the 120-million-year-old Confuciusornis.

University of Manchester paleobiologist Phillip Manning and his colleagues, who had worked on scanning Confuciusornis and other fossils, now turned the synchrotron's powerful x-ray beam onto an unusual fossil. The 50-million-year-old lizard specimen comes from Colorado. What's unusual is that the animal's skin is beautifully preserved, right down to the scales—but the skeleton is gone.

Scanning the fossil for sulfur (in the photo above) or copper produced ghostly silhouettes of the lizard's whole body, since these elements are naturally present in trace amounts throughout an organism. Tuning their scans for phosphorous brought a surprise: dots popped out of the lizard's ghostly head in the shape of a jaw.

In the image above, green is a map of sulfur in the head and neck (check out the scales!). Phosphorous and magnesium are overlaid in red and blue. The authors write that this chemistry is "typical for biomineralized structures." A close look revealed two overlapping bites: a full set of lizard teeth.

Before the synchrotron scanning, researchers thought the unusual Colorado fossil was a 50-million-year-old molted lizard skin. But even animals that shed their skin don't tend to leave behind their entire jaws when they do so. This animal died in one piece.

Although bones and teeth have similar ingredients, the authors write that the structure of teeth makes them more resistant to dissolving. But how did the delicate skin stay intact? "If the acidity of the ground waters are high, bone would be vulnerable," Manning says. "However, high acidity is often helpful in 'tanning' skin to preserve [it]. Think bog bodies from northern Europe."

As researchers continue to peer into the past with the synchrotron, Manning is narrating their progress at his blog. He doesn't anticipate running out of subjects. "We have a few million life forms to wade through," he says. In other words, there are plenty of ghosts of fossils yet to come.


Edwards, N., Wogelius, R., Bergmann, U., Larson, P., Sellers, W., & Manning, P. (2012). Mapping prehistoric ghosts in the synchrotron Applied Physics A DOI: 10.1007/s00339-012-7484-3

Images: Edwards et al.

Dinosaur Age Not Dramatic Enough? Add Fire

As if a world dominated by hungry, house-sized lizards weren't sufficiently exciting, scientists have added another set piece to our image of the Cretaceous: raging wildfires.

The Cretaceous period, which ended about 65 million years ago with the extinction of the dinosaurs, was hot. That's thanks to volcanos that pumped carbon dioxide into the atmosphere and created a greenhouse effect. Researchers from London and Chicago now say it was also a "high-fire" world. Frequent blazes may have kept animals on the run, created some of the fossil beds we study today, and helped determine which plant species survived into the next era.

Led by graduate student Sarah Brown from the Royal Holloway University of London, the researchers tracked the appearance of charcoal in ancient sediments. Like a set of sooty footprints right through the fossil record, the charcoal evidence showed when and where fires had occurred.

The team saw that wildfires had increased during the Cretaceous period. These fires were probably sparked by lightning, and their flames were fanned by the high concentration of oxygen in the ancient atmosphere. Today, oxygen makes up about 21% of our air. But during the Cretaceous, it may have risen as high as 25% or more.

This high oxygen content, the authors say, would have allowed plants to burn without being bone dry. A spark in a green forest, instead of dying out as it would today, might become a full-blown fire.

Brown and her coauthors did not find any evidence that these fires contributed to killing off the dinosaurs. But they note that after a fire burns through a piece land, erosion is likely. There may be rapid flooding or mudslides. In the Cretaceous, these events might have trapped and killed dinosaurs and other animal life--and helped preserve their bones.

The authors point to certain fossil beds that lie in floodplains and contain charcoal, as well as plant and animal remains. These could be sites where wildfires triggered flooding, conveniently sweeping lots of informative fossils into one place for future scientists to find.

Charred plant remains in these fossil beds provide another clue about the effect of fire. As the Cretaceous went on, the types of plants being fossilized gradually changed. Flowering plants, called angiosperms, became more and more common. Gymnosperms--the more ancient, flowerless species such as cone-bearing trees, cycads, and ginkgos--faded into the background.

A charred flower fossil from the Late Cretaceous.

Frequent fires may have given an added edge to the angiosperms. The new types of plumbing these plants had invented let them grow faster and more efficiently. Rather than trees, the flowering plants growing during the Cretaceous seem to have been weedy and shrubby types. After a fire, they could regrow faster than the gymnosperms. And their new growth provided fresh fuel for wildfires, creating a cycle that encouraged the growth of flowering plants and left older models in the dust.

Though fire didn't do in the dinosaurs, then, it may have helped set the stage for the dominant plants of the modern age. (As if we needed any more drama.)

Brown, S., Scott, A., Glasspool, I., & Collinson, M. (2012). Cretaceous wildfires and their impact on the Earth system Cretaceous Research DOI: 10.1016/j.cretres.2012.02.008


Images: Gorgosaurus from Nobu Tamura/Wikimedia Commons; flower fossil from Brown et al.

To Visualize Dinosaurs, Scientists Try Paint-by-Numbers

Now that we know some dinosaurs had down or feathers instead of the scales we used to imagine, there are intriguing new questions to be answered. Did forest-dwelling species use patterned feathers for camouflage? Did other dinosaurs use flashy colors for communication or courtship, like modern birds do? Using new imaging techniques, scientists are beginning to color in their dinosaur outlines. 

In previous studies, researchers have scoured fossils of dinosaurs and early birds for melanosomes, structures in cells that hold the pigment melanin. (Despite the range of colors in our eyes, fur, and skin, most animals only produce one pigment: the brownish melanin. Blues and greens can be created by light-scattering tricks.) The shape of a melanosome can tell researchers what type of color it was responsible for, from black to yellow to red. But melanosomes, like other non-bony structures, break down over time and are hard to find in fossil form. 

Instead of searching for the cellular packages that held pigments, Roy Wogelius and other scientists at the University of Manchester decided to search for traces of metals. Elements such as copper, zinc, and calcium bind to melanin while an animal is alive. Though the melanin decays over time, the metals remain behind.

The researchers used a new imaging technique that's sensitive enough to find and map trace distributions of elements. They first scanned samples from non-extinct species, including a fish eye, bird feathers, and a squid. The distribution of copper turned out to correspond with the most pigmented areas in the animals--the squid's ink sac, for example, was highly coppery.

Then Wogelius and his colleagues turned their scanners to fossils, including Confuciusornis sanctus, an early bird that lived with the dinosaurs. (Confuciusornis was discovered in China and named after who you'd think.) The researchers created a map of copper distribution in the fossil, which you can see below. Copper is shown in red. 

Based on their map, they could then sketch a shaded-in Confuciusornis.

This technique doesn't yet tell us what colors Confuciusornis wore, only where its darkest feathers were. Those areas could have been black or brown or red--or the bird could have colored its feathers through its diet, as a goldfinch or a cardinal does today. Since that kind of coloration doesn't involve melanin, it would be invisible to these scans. But as technology improves and becomes more sensitive to the microscopic tidbits of information hidden in fossils, we may be able to find out what dinosaurs really looked like. We might be able to discard the green and brown lizards plodding through today's books, like the sepia-toned photographs of the past, with something much more lifelike. 

Wogelius, R., Manning, P., Barden, H., Edwards, N., Webb, S., Sellers, W., Taylor, K., Larson, P., Dodson, P., You, H., Da-qing, L., & Bergmann, U. (2011). Trace Metals as Biomarkers for Eumelanin Pigment in the Fossil Record Science DOI: 10.1126/science.1205748

Big Balls (a quiz)

Do you have what it takes to conquer this special-edition, oversized quiz?

1. Data from a NASA telescope recently revealed two giant balls of:

a. ice and rock, hurtling toward Mars

b. garbage, lodged in an air-circulation chute on the International Space Station

c. energy, sandwiching the Milky Way galaxy

d. gas and dust, blocking our view of the Orion nebula

2. Using an iPhone app called Track your Happiness, researchers at Harvard found that:

a. people who daydream the most are the happiest

b. 10% of people claim to never daydream

c. focusing on the task at hand makes people unhappy

d. daydreaming makes people unhappy

3. Last week, researchers reported that ozone depletion is causing:

a. sunburned whales

b. skin cancer in penguins

c. deeper tans among Brazilians

d. a reversal of global warming

4. Researchers in Vietnam discovered a previously undocumented, all-female lizard species...

a. on a menu

b. in a pet store

c. living in their luggage

d. after running one over

5. A British team has proposed a new design for a Mars rover. Instead of rolling across the sandy terrain like Spirit and Opportunity, their rover would:

a. crawl

b. walk

c. fly

d. hop

6. Meanwhile, a new study on pterosaurs says that the 500-pound flying dinosaurs may have launched themselves into flight in a manner similar to:

a. high jumping

b. pole vaulting

c. skipping

d. trapeze-ing

7. New research has revealed which of the following about parrotfish mucus?

a. Parrotfish trap their prey in spit-bubble nets

b. Parrotfish create elaborate spit castles as part of their courtship routine

c. Parrotfish spit contains a potent antiviral agent

d. Parrotfish sleep in spit cocoons to deter bloodsucking predators

8. Scientists at MIT built a robotic tongue in order to study the physics of:

a. dogs lapping water

b. cats lapping water

c. camels spitting

d. goldfish eating

9. Haven't you ever wondered how a fruit fly larva (also called a maggot) keeps its squishy little body from shriveling in the sun while it's munching on rotten fruit? The answer, scientists recently announced, is that the maggot:

a. has tiny eyes all over its body to detect the sun

b. creates a protective spit tunnel as it chews

c. excretes urine from every part of its body

d. ...I'm sorry, I grossed myself out too much to write a fourth option.

10. With testes weighing in at almost 14% of its body mass, the title of World's Largest Testicles has been claimed by a species of:

a. lemur

b. parakeet

c. cricket

d. primitive hominid

Answers are in the comments.