Tag Archives: Rocks

Red Skies.

Silica rains helped form Earth’s crust four and a half billion years ago

Earth’s crust may have been formed in part by atmospheric chemicals which settled on the surface as the planet cooled, McGill University researchers report.

Red Skies.

Image credits David Mark.

We know that about 4.5 billion years ago, a planetoid roughly the same size as today’s Mars slammed into early Earth with enough force to melt the whole thing into a ball of magma. The event was so violent that we believe it led to the formation of the Moon and altered the chemical composition of our planet into the iron-rich Earth we know and love today.

Conventional wisdom holds that following this impact, the Earth gradually cooled down and the outer surface of this ball of lava hardened into a crust — in other words, the rocks on the planet’s surface are igneous in origin. But Don Baker and Kassandra Sofonio, a team of earth scientists from McGill University, say that the event played a direct hand in forming the planet’s modern crust. According to their theory, some of the chemical components we see in the crust today were deposited from the super-heated atmosphere left in the wake of the impact.

Igngaseous

Largely speaking, Earth’s crust comes in two flavors: oceanic and continental. Oceanic crust is the stuff plates are formed of, the rocks that cool from magma at mid-ocean rifts (they are igneous) then get subducted and recycled on the other side of the plate. It’s usually pretty thin and it’s what the ocean floor rests on.

Continental crust is the stuff that we actually live on. These thicker slabs of rock form on top of oceanic crust and reach high enough altitudes (usually) to form continents above water — hence their name. The rocks that go into continental crust can come from many different places, but what’s important now is that more than 90% of these rocks are estimated to be formed from silica-rich minerals, such as feldspar and quartz. Which, as you may have guessed, adds up to a lot of silica.

So where did all this silica-rich crustal material come from? The duo says that the collision 4.5 billion years ago turned the atmosphere into high-temperature steam which dissolved the rocks in the surface into a gaseous solution.

“These dissolved minerals rose to the upper atmosphere and cooled off, and then these silicate materials that were dissolved at the surface would start to separate out and fall back to Earth in what we call a silicate rain,” Baker says.

To test their theory, the team recreated the conditions of early Earth in the lab. They used a mix of bulk silicate materials and water which was enclosed in gold palladium capsules, then heated to 727 degrees Celsius (1340 Fahrenheit) at 100 atm to simulate conditions in the atmosphere about 1 million years after the moon-forming impact.

Using previous work on rock-water interactions at high pressure as a starting point, the team successfully recreated a “surprisingly similar” material to the Earth’s modern crust. The authors believe that following the impact, surface silicate rocks would dissolve and separate, rising to the upper layers of the atmosphere. Here, they cooled off enough to crystallize and fall back to Earth in a “silicate rain.” Sofonio christened the process “aerial metasomatism.”

One surprising implication of the paper is that it could provide researchers with a better understanding of how to spot planets fit for human habitation, or even those that harbor alien life.

“This time in early Earth’s history is still really exciting,” he adds. “A lot of people think that life started very soon after these events that we’re talking about. This is setting up the stages for the Earth being ready to support life.”

The paper “A metasomatic mechanism for the formation of Earth’s earliest evolved crust” has been published in the journal Earth and Planetary Science Letters.

There’s a museum in Japan that honors rocks which resemble human faces

Just a two hours drive northwest of Tokyo, you can find one of the world’s most entertaining museums. It’s called the Chinsekikan, Japanese for ‘hall of curious rocks’, and inside, visitors can find more than 1,700 rocks that look peculiar in some way, 900 of which resemble faces. Among some of the celebrities housed at this Madame Tussaud’s for minerals are E.T., Elvis Presley, and, of course, Jesus Christ.

Where nature is the only artist

The head curator Yoshiko Hayama.

This one of a kind museum was founded by Shozo Hayama who has collected strange-shaped, unaltered rocks for fifty years. Since Hayama passed away in 2010, the museum has been run by Yoshiko Hayama, the late founder’s wife.

Besides the rocks that resemble real and fictional celebrities, among them Japanese sensation Donkey Kong, Mickey Mouse, Nemo the clownfish, or the mercurial Boris Yeltsin, there are also more general human face-resembling rocks such as the ‘chorus rocks’ featured below.

Big "O-faced" rocks.

Big “O-faced” rocks.

The Chinsekikan museum has been featured on many popular Japanese TV shows.  Every rock on display from the collection is completely unaltered keeping true to Shozo Hayama’s legacy — that nature is the only artist.

Elvis

Wrestler and Japanese politician Antonio Inoki

Wrestler and Japanese politician Antonio Inoki

Turtle shell

Turtle shell

Some of the celebrity-lookalike rocks are more convincing than others.

Mickey Mouse

Cold Wind Monjiro from the Japanese novel and TV drama Kogarashi Monjiro

Nemo

Even Mikhail Gorbachev is on the list.

Geologically speaking, the anthropomorphic features you see etched on the rocks are due to weathering of certain minerals and imperfections. Weathering and cracking usually occur along a plane of weakness or a sedimentary layer. Many of the rocks featured in this article, for instance, seem weathered by flowing water. Some minerals are more susceptible to sculpting by natural phenomena than others. Quarts, for instance, is much less likely to weather than micas.

There had to be a Jesus too.

As for what compelled the founder of the museum to amass such a collection, Shozo Hayama likely had some degree of pareidolia, which is the tendency to perceive human traits where none actually exist. It’s what causes some people to claim there are pyramids on Mars shaped like a human face or to see Jesus in pieces of toast or sections of timber. A recent study suggests an anomalous interplay between the brain’s frontal cortex and posterior visual cortex is what leads some people to see faces in objects more often than others. But it is totally normal to notice faces in rocks or other objects because our brains are hard-wired to spot such patterns.

The author's own pareidolia. If this isn't Scumbag Steve, I don't know what rock could ever be.

The author’s own pareidolia. If this isn’t Scumbag Steve, I don’t know what rock could ever be.

Chinsekika definitely looks fun to visit and a welcomed breath of fresh air if you enjoy visiting more traditional geological museums.

All pics via Kotaku, Another Tokyo, Yukawanet, and Sankei Photo.

NASA released the most awesome pictures of Mars’ surface to date

Mars’ rock formations are oddly familiar, and their similarity to what we see on Earth has gotten scientists pretty excited.

This view from the Mast Camera (Mastcam) in NASA’s Curiosity Mars rover shows an outcrop of finely layered rocks within the Murray Buttes region on lower Mount Sharp.
Image credits NASA/JPL-Caltech.

NASA’s Curiosity rover has been busy poking around the lower slopes of Mount Sharp on Mars and has sent back some of the most striking color images of the Red Planet to date.

“Curiosity’s science team has been thrilled to go on this road trip through a bit of the American desert Southwest on Mars,” reports Ashwin Vasavada, a scientists working on the Curiosity project.

The pictures were taken on September 8th on the Murray Buttes area on the lower slopes of Mount Sharp — a towering peak rising 5.5 km (18,000 ft) in the center of Mars’ huge Gale crater. It was first identified in the 1970s and has all the makings of a heavily eroded sedimentary formation. While this is a pretty common occurrence here on Earth where there is a lot of wind and water to carry minerals from one place to another, it’s a surprising find on Mars. Researchers estimate that the peak took around 2 billion years to form, but have no idea where the sediments came from or what medium helped deposit them.

Murray Buttes is a relatively elevated area, littered with buttes (isolated hills with steep or vertical slopes and flat tops) and mesas. They’re pretty similar, with the only difference between them being size — buttes are like tiny flat-topped hills, and mesas are medium-sized flat-topped hills.

Sloping buttes and layered outcrops within the Murray Buttes region on lower Mount Sharp.
Image credits NASA / JPL-Caltech.

They were formed over millions of years by erosion working the crater’s sandstone floor. The new pictures Curiosity sent back gives us the best view we’ve ever seen of their shapes and the layers of rock from which they formed, a treasure trove of information for the team back home

“Studying these buttes up close has given us a better understanding of ancient sand dunes that formed and were buried, chemically changed by groundwater, exhumed and eroded to form the landscape that we see today,” says Vasavada.

The rover will conclude its month-long exploration of the Murray Buttes with a drilling campaign in the region’s southernmost buttes. After that, it will move higher up the slopes of Mount Sharp.

Image credits NASA / JPL-Caltech.

Image credits NASA / JPL-Caltech.

NASA said that they will piece the images together to assemble several large, color mosaics of the area in the near future — after they’re done learning all they can from these awesome snaps.

 

Rocks prove Mars used to resemble the Earth a lot — but no, that doesn’t mean there was life on it

Curiosity has discovered high concentrations of manganese oxides on Mars, leading scientists to believe that the planet was once very similar to Earth.

*Geological drum-roll intensifies.*
Image credits NASA/JPL.

Mars may have once had an Earth-like, oxygen-rich atmosphere enveloping it according to JPL’ Curiosity team. The rover found high concentrations of manganese oxides in the planet’s rocks while blasting through Gale Crater with its laser-firing ChemCam.

On Earth, these compounds first appear at a time when our atmosphere was going through a dramatic change: a microbe-powered oxygen enrichment.

“The only ways on Earth that we know how to make these manganese materials involve atmospheric oxygen or microbes. Now we’re seeing manganese oxides on Mars, and we’re wondering how the heck these could have formed?” says Los Alamos planetary scientists and lead study author Nina Lanza.

Finding these levels of manganese oxide deposits are a dead giveaway for an oxygen rich environment, Lanza adds.

“These high manganese materials can’t form without lots of liquid water and strongly oxidizing conditions. Here on Earth, we had lots of water but no widespread deposits of manganese oxides until after the oxygen levels in our atmosphere rose,” she said.

Curiosity found the samples in Gale Crater (the circled point in the top left.)
Image credits NASA/JPL

But without any bugs living on Mars, how did these rocks form? Lanza believes it comes down to Mars losing its magnetic field.

At one point, the planet had large amounts of liquid water and a protective magnetic bubble, just like our Earth does today. But, while our planet’s atmosphere was pumped full of oxygen by microorganisms, Mars gained its oxygen from water — as its magnetic field became weaker, it could no longer stave off the flow of cosmic ionizing radiation, which broke the liquid down into hydrogen and oxygen atoms.

Much of that oxygen was absorbed by the planet’s now-iconic iron-oxide rocks, gradually giving it the color of rust. Manganese-oxides require much more oxygen to form, however, suggesting that Mars had a lot more of it in its atmosphere than we previously believed.

So just because Mars once had both oxygen and water, that doesn’t mean there was ever life on the planet. Bummer, I know.

“It’s important to note that this idea represents a departure in our understanding for how planetary atmospheres might become oxygenated,” Lanza concludes.

Still, Lanza admits that the theory will be hard to prove. However, it’s the best one we have for now, or until Curiosity stumbles upon a Martian bug. Or a martian.