Category Archives: Geology

Where does desert sand come from?

Sand is a great traveller. Go to the seaside for the day and it’ll ride home on your shoes or sneak into your picnic sandwiches. You may wonder, as you shake sand from your bag on the beach: ‘where did all this sand come from and how long’s it been here?’ Dr Pieter Vermeesch and colleagues had the same question about the sand in the Namib Sand Sea – one of the world’s oldest and largest sand deserts. We know little … Continue reading

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How The Sahara Desert Was Made

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Volcano Eruption in Papua New Guinea

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Mystery solved: ‘Sailing stones’ of Death Valley seen in action for the first time

moving stones

Racetrack Playa is home to an enduring Death Valley mystery. Littered across the surface of this dry lake, also called a “playa,” are hundreds of rocks — some weighing as much as 320 kilograms (700 pounds) — that seem to have been dragged across the ground, leaving synchronized trails that can stretch for hundreds of meters. What powerful force could be moving them? Researchers have investigated this question since the 1940s, but no one has seen the process in action … Continue reading

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Aogoshima Island

This is an aerial view of Aogoshima Island, one of about a dozen volcanic islands south of Tokyo in the Philippine Sea, seven of which are inhabited. Aogoshima is the southernmost of these inhabited islands. In the Western Pacific, the Pacific Plate is subducting beneath a series of plates, including the Eurasian plate to the North beneath Japan and the Philippine Sea plate here. That subduction leads to a linear series of volcanoes trending south from Tokyo where the Pacific, … Continue reading

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Devils Tower

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Devils Tower is anigneous intrusion or laccolith in the Black Hills near Hulett and Sundance in Crook County, northeastern Wyoming, above the Belle Fourche River. It rises dramatically 1,267 feet (386 m) above the surrounding terrain and the summit is 5,114 feet (1,559 m) above sea level. Devils Tower was the first declared United States National Monument, established on September 24, 1906, by President Theodore Roosevelt. The Monument’s boundary encloses an area of 1,347 acres (545 ha). In recent years, about 1% of the Monument’s 400,000 annual visitors climbed Devils Tower, mostly using traditional climbing techniques. The Arapaho, Crow, Cheyenne, Kiowa, Lakota, and Shoshone tribes had cultural … Continue reading

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Normal Fault

fault

This image shows a classic normal fault in fairly young (<20 million year old) sedimentary rocks outside of Harrison, Montana. The fault plane is clear and it dips to the right in this image. If you look at both sides of the fault, layers on the right and left are nearly identical, just the layers on the right have moved down. The layers even have specific features; the more resistant layer sticks out, while the weaker layer has been used … Continue reading

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Alteration

Volcanic rocks are born as lavas or layers of ash, and stack up eruption after eruption, sometimes thick enough to form islands such as Japan and Iceland (in the featured image) on the mid Atlantic ridge. Much of the rock in the latter is basaltic, but gets transformed after its birth into a variety of chewed up and brightly coloured rock remnants. As ground or sea water percolates into the lava, it interacts with the magma or pressure heated rocks … Continue reading

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Viruses Make Zombies of Deep Sea Vent Bacteria

deepsea-vent

Viruses hijack bacteria that feed on sulfur-spewing vents on the ocean’s floor and then reprogram the bacteria’s DNA, a new study finds, essentially brainwashing the bacteria to devour more of the chemicals erupting from the vents. The bacteria then burn up their stored sulfur reserves faster. These overeating zombie bacteria create excess energy that the viruses use to reproduce, until the bacteria burst and release a fresh wave of virus particles. Microbiologists knew that surface-dwelling viruses could take over bacteria that … Continue reading

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Unique Mineral Discovered In Australia

Screen Shot

A previously unknown mineral has been discovered in a remote location in Western Australia. The mineral, named putnisite, appears purple and translucent, and contains strontium, calcium, chromium, sulphur, carbon, oxygen and hydrogen, a very unusual combination. While dozens of new minerals are discovered each year, it is rare to find one that is unrelated to already-known substances. “Most minerals belong to a family or small group of related minerals, or if they aren’t related to other minerals they often are to a … Continue reading

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Moeraki Boulders

moeraki

The Moeraki Boulders are unusually large and spherical boulders lying along a stretch of Koekohe Beach on the wave-cut Otago coast of New Zealand between Moeraki and Hampden. They occur scattered either as isolated or clusters of boulders within a stretch of beach where they have been protected in a scientific reserve. The erosion by wave action of mudstone, comprising local bedrock and landslides, frequently exposes embedded isolated boulders. These boulders are grey-colored septarian concretions, which have been exhumed from … Continue reading

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Scientists reconstruct ancient impact that dwarfs dinosaur extinction blast

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Piture this: A massive asteroid almost as wide as Rhode Island and about three to five times larger than the rock thought to have wiped out the dinosaurs slams into Earth. The collision punches a crater into the planet’s crust that’s nearly 500 kilometers (about 300 miles) across: greater than the distance from Washington, D.C. to New York City, and up to two and a half times larger in diameter than the hole formed by the dinosaur-killing asteroid. Seismic waves … Continue reading

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How Earth might have looked

Break-up of the supercontinent Gondwana about 130 Million years ago could have lead to a completely different shape of the African and South American continent with an ocean south of today’s Sahara desert, as geoscientists from the University of Sydney and the GFZ German Research Centre for Geosciences have shown through the use of sophisticated plate tectonic and three-dimensional numerical modelling. The study highlights the importance of rift orientation relative to extension direction as key factor deciding whether an ocean … Continue reading

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The oldest rock ever found on Earth

Ancient zircon crystals discovered in Western Australia have been positively dated to 4.374 billion years, confirming their place as the oldest rock ever found on Earth, according to a new study. The research reported in the journal Nature Geoscience, means Earth began forming a crust far sooner than previously thought, following the giant impact event which created the Earth-Moon system 4.5 billion years ago. “That age is 300 million years older than the oldest previously dated age [of other rocks], and … Continue reading

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Japan’s new island grows and grows

Japan has acquired some new territory in the Pacific Ocean following a powerful volcanic eruption. A new island has emerged from the sea, 1,000km south of the capital Tokyo. The islet is growing and changing shape all the time. BBC’s Rupert Wingfield-Hayes reports.

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3.5 Billion Year Old Life Found

Gloppy mats of microscopic life left the same signature on coastal and river bank sediments 3.48 billion years ago that they do today. Earth scientists recently discovered that signature, known as a “microbially induced sedimentary structure” (MISS), on rocks from 300 million years earlier than any previously known MISS fossils. To this day, MISS still forms in pools of stagnant water along rivers and lakes or in the muck of coastal mud flats. Complex communities of microorganisms form layers of … Continue reading

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Quartz Gemscape Sculpture

quartz

In most gems inclusions are perceived as flaws, but sometimes they can grace them with extra beauty or an interesting geological story. These are known as scenic inclusions and are now highly sought after, though they were routinely discarded not that long ago. This sculpture of quartz with natural inclusions of green chlorite and a red mineral, possibly hematite, was created by gem artist Lawrence Stoller. via Facebook. Image credit: Lawrence Stoller

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The Worlds Largest Volcano

worlds largest volcano

A University of Houston (UH) professor led a team of scientists to uncover the largest single volcano yet documented on Earth. Covering an area roughly equivalent to the British Isles or the state of New Mexico, this volcano, dubbed the Tamu Massif, is nearly as big as the giant volcanoes of Mars, placing it among the largest in the Solar System. William Sager, a professor in the Department of Earth and Atmospheric Sciences at UH, first began studying the volcano … Continue reading

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Geoscientists discover hillslopes can reveal geographic activity below

A team of geoscientists from the U.K. and the U.S. has found that measuring the contour of hilly regions using a laser scanner can reveal aspects of the geographical history that led to its formation. In their paper published in the journal Science, the team describes laser scan analysis they undertook of a pressure ridge in California and the model they created using data they’d obtained. Scientists have known for many years that studying the shape of hills can sometimes … Continue reading

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Earth’s gold came from colliding dead stars

We value gold for many reasons: its beauty, its usefulness as jewelry, and its rarity. Gold is rare on Earth in part because it’s also rare in the universe. Unlike elements like carbon or iron, it cannot be created within a star. Instead, it must be born in a more cataclysmic event – like one that occurred last month known as a short gamma-ray burst (GRB). Observations of this GRB provide evidence that it resulted from the collision of two … Continue reading

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