Cratered Cones in the Cydonia Region of Mars
This observation focuses on an unusually high density of cratered cones, imaged previously by the Mars Orbiter Camera. These cones could possibly be mud volcanos. On Earth, a large number of these formations are located in Gobustan, Azerbaijan and the Caspian Sea.
If they are mud volcanoes, what are the processes on Mars that might have created them? At HiRISE resolution, we can look for subtle flow features and compare these with other cratered cones elsewhere on Mars.
This caption is based on the original science rationale. - Written by: HiRISE Science Team (audio by Tre Gibbs) (27 February 2013)
This is a stereo pair with ESP_025518_2210.
(via: NASA/JPL/University of Arizona)
These are no ordinary fossils (if there is such a thing): these incredible relics are made of solid opal, sometimes with rainbows of shimmering color. Australia is the only place on Earth where opalized animal fossils are found. These fossils are of global scientific interest and are among the most beautiful and valuable in the world.
How do opalized fossils form?
Opal forms in cavities within rocks. If a cavity has formed because a bone, shell or pine cone was buried in the sand or clay that later became the rock, and conditions are right for opal formation, then the opal forms a fossil replica of the original object that was buried. We get opalized fossils of two kinds:
i. Internal details not preserved: Opal starts as a solution of silica in water. If the silica solution fills an empty space left by a shell, bone etc that has rotted away - like jelly poured into a mould - it may harden to form an opalized cast of the original object. Most opalized shell fossils are ‘jelly mould’ fossils - the outside shape is beautifully preserved, but the opal inside doesn’t record any of the creature’s internal structure.
ii. Internal details preserved: If the buried organic material hasn’t rotted away and a silica solution soaks into it, when the silica hardens it may form an opal replica of the internal structure of the object. This happens sometimes with wood or bone.
Images in this order: Opalized Dinosaur tooth, Ammonite,Shell x2, Dinosaur bone, Wood, Pineapple, Mussel shell, Belemnite. Click on each to view in more detail.
Ginkgo Trees Stand Test of Time
“Living fossil” is an informal term used by biologists to describe species that lack living relatives. While you might not personally think being called a fossil is a compliment, these organisms are actually quite impressive survivors. The Ginkgo biloba tree, for example, is strange and unique amongst contemporary plants but incredibly similar to fossils dating back to the Permian, almost 270 million years! This means that even though every single other lineage of the Ginkgo’s relatives changed and adapted beyond recognition or died out, there are still Ginkgo trees growing today that would be indistinguishable from trees from hundreds of millions of years ago. If that fails to impress you, consider this: in Hiroshima, Japan there are still a handful of Ginkgo trees that survived the dropping of the atom bomb in 1945 living to the present day! If these hardy trees can withstand a disturbance of an A-bomb’s magnitude, it is no wonder they have managed to remain viable when so many other ancient plants could not.
Guest post written by Reggie Henke
How to Measure the Explosive Power of Volcanoes
By George Dvorsky
Scientists have scales to measure the strength of natural phenomena like earthquakes and hurricanes. But what about the eruptive power of volcanoes? For that, geologists use the Volcanic Explosivity Index. Here’s how it works.
The Volcanic Explosivity Index (VEI) was first proposed in 1982 by Christopher Newhall of the U.S. Geological Survey and Stephen Self of the University of Hawaii. Their intention was to develop a scale to estimate the explosive magnitude of historical volcanoes.
To that end, they came up with an incrementing logarithmic scale to measure the magnitude of past explosive eruptions, which Newhall described as a “semiquantitative compromise between poor data and the need in various disciplines to evaluate the record of past volcanism.”
But establishing the parameters for a useful scale proved easier said than done. Unlike earthquakes or hurricanes, there are different types of volcanoes, and they produce different products, like massive plumes of ejected rock and ash, or molten lava flows.
Moreover, and as scientists later learned, volcanoes also churn-out varying degrees of sulfur dioxide at rates irrespective of eruptive power. It’s for that reason that the VEI had to be rejected as a way to measure an eruption’s potential impact on the climate. Today, it’s used exclusively to measure the explosive power of both historic and new eruptions.
How the Scale Works
Similar to the Richter scale, the VEI uses a numerical index ranging from 0 to 8. Each increment represents an 10-fold increase in explosivity. Factors that are taken into account include the volume of pyroclastic material (including ashfall, pyroclastic flows, and other ejecta), the height of the eruption, duration in hours, and a number of other qualitative measurements.
So, given that the scale is primarily driven by the volume ejected, it goes like this:
- VEI 0: eruptions that produce less than 0.0001 cubic kilometer of ejecta (small events that typically produce flowing lava, which is called an effusive eruption)
- VEI 1: eruptions that produce between 0.0001 and 0.001 cubic kilometers of ejecta
- VEI 2: eruptions that produce between 0.001 and 0.01 cubic kilometers of ejecta
- VEI 3: eruptions that produce between 0.01 and 0.1 cubic kilometers of ejecta
And so on until we get to VEI 8.
So, a VEI 5 is roughly 100 times more explosive than a VEI 3, and a VEI 8 is a million times more powerful than a VEI 2. Sometimes a + symbol is added to account for the wide degree of variation between each number in the scale.
The VEI doesn’t go past 8, but that doesn’t mean a VEI 9 isn’t impossible. Scientists may still uncover evidence of such an event buried somewhere in the geological record.
The Center of the Earth Is as Hot as the Sun
Crushed by the weight of the thousands of kilometers of liquid iron and sulfur, superheated metal and minerals and cool crustal rock above, the Earth’s core is under immense pressure. Heated from within by friction and by the decay of radioactive material and still shedding heat from the initial formation of the planet 4.5 billion years ago, the planet’s core is blisteringly hot. In new research, scientists studying what the conditions at the core should be like found that the center of the Earth is way hotter than we thought—around 1,800 degrees hotter, putting the temperature at a staggering 10,800 degrees Fahrenheit.
This superheated core, says the BBC, is about as hot as the surface of the Sun.
Scientists know the Earth’s core, a multi-layered structure with a solid iron core spinning in a sea of liquid iron and sulfur, is hot. But, cut off from direct study by all the stuff in between the core and the surface, getting an accurate idea of the core’s properties is a daunting feat.
Led by Simone Anzellini, the French research team did their best bet to reproduce the core’s properties in the lab: they took a bunch of iron and crushed it between two pieces of diamond. Then they shot it with a laser. The apparatus produces massive pressures and superheated temperatures. This let them study how the iron behaved under such intense conditions and gave them a window into the conditions found at the planet’s center.
Knowing how hot the Earth’s core is can add to our understanding all sorts of wonders, from the existence of the planetary magnetic field, to the propagation of seismic waves after an earthquake, to the birth of the Earth itself.
Where Does Charcoal, or Black Carbon, in Soils Go?
Scientists have uncovered one of nature’s long-kept secrets—the true fate of charcoal in the world’s soils. The ability to determine the fate of charcoal is critical to knowledge of the global carbon budget, which in turn can help understand and mitigate climate change.
However, until now, researchers only had scientific guesses about what happens to charcoal once it’s incorporated into soil. They believed it stayed there.
Surprisingly, most of these researchers were wrong.
The findings of a new study that examines the result of charcoal once it is deposited into the soil are outlined in a paper published this week in the journal Science. The international team of researchers was led by scientists Rudolf Jaffe of Florida International University and Thorsten Dittmar of the German Max Planck Society.
“Most scientists thought charcoal was resistant,” says Jaffe. “They believed that once it was incorporated into soils, it stayed there. But if that were the case, soils would be black.”
Charcoal, or black carbon, is a residue generated by combustion including wildfires and the burning of fossil fuels. When charcoal forms, it is usually deposited into the soil.
“From a chemical perspective, no one really thought it dissolved, but it does,” Jaffe says. “It doesn’t accumulate for a long time. It’s exported into wetlands and rivers, eventually making its way to the oceans.”
It all started with a strange finding in the Everglades.
Balancing Rocks in Central Oregon
“Geologists explain that the formations are the result of the aging, tilting and erosion of two layers of consolidated volcanic ash, known as tuff.
These ash flows originated from the Cascade volcanoes to the west many thousands of years ago. The top layer of tuff was tougher so to speak than the bottom layer, so as the ground tilted and cracked and the softer bottom layer was eroded by wind and water, top-heavy rock pedestals remained.
Discovered by surveyors way back in the 1850s, the unusual rocks were known to only a handful of people for many decades. They remained hidden in a forest of pine and juniper until a forest fire in 2002 denuded the area. Visible now from Forest Service roads and from boats on the popular Lake Billy Chinook below, the rocks are visited more frequently. Sadly, the formations pose an irresistible temptation to immature vandals and a few of the pedestals have been toppled. Fortunately, most are far more massive, stable and durable than they appear.”— Brad Goldpaint
A geyser is a spring that intermittently discharges water and steam turbulently. The most powerful geyser has been observed ejecting water to 460 m (1,500 ft) (Waimangu geyser, now extinct). For a geyser to occur, three geologic conditions are required.
The heat needed to form a geyser comes from magma that is close to the Earth’s surface. For this reason, geysers are associated with volcanic areas.
An water source must travel underground in deep pressurized fissures, where it can be exposed to the hot crust
A Plumbing System
Fractures, faults, porous spaces and cavities must provide a natural reservoir to hold the heating water. Constrictions in the system is needed to build up pressure before an eruption.
As the underground reservoir fills, the heated water rises by convection. As it rises, the water at the top of the column cools, but due to restricted space, it is unable to cool the whole system by convective cooling. This lid of cold water presses down against the hot water below, increasing the pressure in the reservoir.
The high pressure allows for the water to become superheated. The water at the bottom eventually becomes steam and rise up the column. As they exit the vent, the water lid at the top of the column is spilled out, releasing the pressure under it. With this change in pressure, the superheated water rapidly boils and is ejected out of the vent.
(Geysir, Iceland depicted)
Howard Ignatius on Flickr
The Issaouane Erg (sand sea) is located in eastern Algeria between the Tinrhert Plateau to the north and the Fadnoun Plateau to the south. Ergs are vast areas of moving sand with little to no vegetation cover. Considered to be part of the Sahara Desert, the Issaouane Erg covers an area of approximately 38,000 km2. These complex dunes form the active southwestern border of the sand sea.
The most common landforms in the image are star dunes and barchan (or crescent) dunes. Small linear dunes appear at top left. Star dunes are formed when sand is transported from variable wind directions, whereas barchan dunes form in a single dominant wind regime. The superimposition of two dune types suggests that wind regimes have changed through time. The active nature of this portion of the Erg is well illustrated by this image—smaller dunes form and migrate along the flanks of the larger dunes and sand ridges. Occasional precipitation fills basins formed by the dunes; as the water evaporates, salt deposits are left behind which appear as bluish-white areas.
Astronaut photograph ISS010-E-13539 was acquired January 16, 2005 with a Kodak 760C digital camera with an 800 mm lens, and is provided by the ISS Crew Earth Observations experiment and the Image Science & Analysis Group, Johnson Space Center. The International Space Station Program supports the laboratory to help astronauts take pictures of Earth that will be of the greatest value to scientists and the public, and to make those images freely available on the Internet. Additional images taken by astronauts and cosmonauts can be viewed at the NASA/JSC Gateway to Astronaut Photography of Earth.
Instrument: ISS - Digital Camera
THE ULTIMATE CHRONOSTRATIGRAPHIC CHART
Ray Troll is a world-renowned Alaska-based artist, specializing in fish and paleontology art. This is from his Pancakes and Geology: Cruisin’ the Fossil Freeway.
I drew this image for the Cruisin’ the Fossil Freeway book and exhibit I did with Dr. Kirk Johnson. … I truly believe that everyone should know the geologic ages of our planet. They should be taught in kindergarten right alongside the ABCs as far as I’m concerned. I’m dead serious about this folks. And hey… they’re surprisingly easy to memorize and having this t-shirt in your wardrobe will make it even easier.
Website: Troll Art
Zhangye Danxia - Geology From a Storybook
Long ago, colorful sediments were deposited in western China, layer after layer, century after century. If you were there at the time, you would have seen unremarkable ground, a single hue of dirt no different from a thousand other places on Earth.
But after thousands and thousands of years subject to the forces of pressure and tectonic movement, the total of those layers has been pushed upward, letting us peek at a rainbow-hued slice of Earth’s past perhaps unmatched on this planet. The planet looks more like the cross-section of a jawbreaker candy than layers of rock in these photos, near Zhangye, China.
The Zhangye formation, not to be confused with this danxia, a UNESCO heritage site, reminds us how our crust is heaved and hurled throughout the ages, a slow evolution that will continue into the distant future. It’s yet another story of Earth’s past, written in stone, but perhaps with the same pen as a fantasy storybook.
What Is Fracking?
The fracking frenzy in North Dakota has boosted the U.S. fuel supply — but at what cost? Watch this video animation to see how the process of hydraulic fracturing, or fracking, is used to extract oil and natural gas from shale formations deep underground.
Sinkholes: An Introduction
I don’t know how many of you have heard this news, but a massive sinkhole in Florida took the life of a man while he was sleeping in his bed. The area is very unstable, and the house is being demolished. The neighbouring home was also compromised, and both families had only a short amount of time to retrieve precious items within the homes.
In such a tragic event as this - and because this deals with geologic topics I often focus on - I felt very compelled to talk about the importance of knowing your area, as well as signs of how to contact officials if you find you may be in danger of sinkholes. I’ve personally dealt with sinkholes on too many (planned & unplanned) occasions, have fallen in them, have rescued animals from them, and had my past home demolished because of them. I feel for this family greatly.
The photos above are screencaps from the video on nbcnews.com that accompanies the story. There are examples of past sinkholes, as well as the diagrams giving you a cross section with the general way they work.
I’ve studied sinkholes from the small to the massive. They can range in all sorts of sizes: from length, to width, to depth. Just goole “sinkhole” and you will find a whole bunch of photos. Here’s some from National Geographic that show the world’s most well known pits.
Sinkholes can occur anywhere on Earth, at any time, and the process that manifests before they collapse can be sudden or many, many years in the making. These events are all due to erosion. Much of the time, underground caverns/voids form under the karst process when water erodes the vulnerable soluble bedrock (like limestone), making the ground above unstable over a period of time until it collapses. Here are a few diagrams other than the ones above: state.fl.us, esi.utexas.edu.
Sinkholes also are not always isolated, as underground drainage (natural and artificial) can lead to networks of caverns and underground streams which contribute to the general weakening of a certain area. One may form today, but another could form within minutes, days, or years from the other. In the second photo above, the states highlighted are ones that have been found to be more vulnerable to sinkholes in the US.
I explained the geological term for “sinkhole” above, but the word is more widely used in media to discuss any depression that forms on the Earth’s surface. Many sinkholes can occur due to piping, mines, or anything artificially made that has compromised the stability of the surrounding rock too. There are “sinkholes” (technically: piping pseudokarst) that have occurred like the ones in Guatemala, where the city lies on hundreds of feet of volcanic deposits, and ageing piping was part of the area’s demise.
When it comes to sinkholes in your area, it’s best to do research and read about past incidents in your town, study what your house/area sits on, and read about your climate. If you find yourself surrounded by small sinkholes, there’s a good chance something bigger is below. Speaking from experience, when you’re in a foot of water, and the surface is being covered quickly with developing bubbles all around you, get out.
Usually, with the thousands of sinkholes that happen each year, most of the time no one is severely hurt. Though, this story is a sad reminder of why we must continue to study Earth Sciences, learn from these events, and figure out what we can do to prevent anyone else from being injured or killed.
Microscopic Images of a Chondrules in Chondrite Meteorite
Chondrites are stony meteorites that have not been modified due to melting or differentiation of the parent body. They formed when various types of dust and small grains that were present in the early solar system accreted to form primitive asteroids..
— Mila Zinkova
“Within Two Worlds depicts an alternate perspective by giving us the illusion of times movement, signifying a beginning and end within a world of constant contradiction. It appears you are traveling in the midst of a dream, half-sleeping, half-waking, and touching the arch connecting heaven and earth.”