Tag: volcanoes

The Mystery Of Blue Diamonds And Where They Come From Finally Solved

They are the world’s most expensive diamonds, with some stones valued at £100 million.

But until now nobody has known how rare blue diamonds are made or where they come from.

Now scientists have discovered that they are formed 400 miles down in the Earth, around four times as deep as clear diamonds, where the element boron combines with carbon in such extreme pressure and heat that it crystallizes into the world’s most precious stone.

And because boron is mostly found on the Earth’s surface, scientists believe that it must have travelled down into the mantle when tectonic plates slipped beneath each other.

Eventually volcanic action brought the diamonds up closer to the surface.




The study, published in the journal Nature, suggests blue diamonds are even rarer than first thought.

We now know that the finest gem-quality diamonds come from the farthest down in our planet.”  said Steven Shirey, of the Carnegie Institution of Science.

Blue diamonds have always held a special intrigue. The world’s most famous jewel, the Hope Diamond, which was once owned by Louis XIV, Marie-Antoninette, and George IV was said to be cursed with many of its owners and their families coming to a sticky – and often headless – end.

The postman who delivered the Hope Diamond to its current location in the National Museum of Natural History in Washington DC had his leg crushed in a lorry accident shortly after and then his house burned down.

But the value and rarity of blue diamonds makes them difficult to study and researchers at the Carnegie Institution have spent two years tracking down and studying 46 blue diamonds from collections around the world.

And they were looking for the rarest of blue diamonds, those which include tiny mineral traces called inclusions which hint at their origins.

These so-called type IIb diamonds are tremendously valuable, making them hard to get access to for scientific research purposes,” said lead author Evan Smith of the Gemological Institute of America, adding,

“And it is very rare to find one that contains inclusions, which are tiny mineral crystals trapped inside the diamond.”

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Could Hawaii Volcano Explode Like Mount St. Helens In 1980?

Nearly 20 fissures have opened since the Kilauea volcano started erupting almost two weeks ago.

A fissure that opened Sunday led authorities to order 10 people to flee their homes, Hawaii County Managing Director Wil Okabe said.

With Hawaii’s Kilauea volcano continuing to belch out lava, ash and noxious fumes, people are wondering: Could it soon explode in a deadly and catastrophic fashion, like Mount St. Helens did in 1980?

Probably not, said University at Buffalo geologist Tracy Gregg. “Kilauea and Mount St. Helens are different in almost every imaginable way,” she said.

Michael Poland of the U.S. Geological Survey, agreed, saying there’s no concern that Kilauea could explode like Mount St. Helens did back in 1980.

The volcanoes are very different in composition and style,” he said.




One big difference? Gas bubbles, Gregg said.

The magma, what lava is called when it’s still underground, in Mount St. Helens is thick and sticky — think cold peanut butter — and full of gas bubbles. So it’s prone to violent explosions as it reaches the surface.

However, Kilauea’s lava is runnier — like honey — and contains less gas, so it flows more easily and doesn’t explode.

Kilauea is not likely to have a Mount St. Helens-style eruption because it’s made of runny lava that lets the gas bubbles escape, and the lava doesn’t contain much dissolved gas to begin with,” Gregg said.

Poland said gas is what drives explosive eruptions. That’s why high-silica volcanoes (like Mount St. Helens) tend to erupt more explosively than low-silica volcanoes (like Kilauea).

Silica is a rock-forming compound that helps determine the thickness of the lava.

Mount St. Helens, in southwestern Washington state, blew its top in a ferocious explosion on May 18, 1980, killing 57 people in one of the biggest volcanic eruptions in U.S. history.

An aerial view of the eruption of Mount St. Helens, Skamania County, Washington on May 18, 1980.

The two volcanoes are also different shapes: Kilauea is a gently sloping shield volcano, unlike Mount St. Helens, which is a steep-sided stratovolcano, also known as a composite volcano.

This allows for different types of eruptions, with shield volcanoes being much less violent.

However, Kilauea has experienced violent explosive eruptions in the past, Poland said, including several from roughly 1500-1800.

But the conditions to have the sorts of explosions that occurred during do not exist right now, so such explosions are not expected,” he said.

Any explosions on Kilauea in the near future would be relatively minor, caused by the mixing of hot rock and water, Poland said.

While minor, this activity could still be hazardous to anyone that is in the vicinity of the eruptive vent at the summit,” such as within a few hundred yards.

“This is one of the reasons that Hawaii Volcanoes National Park remains closed,” Poland said.

Over the past two weeks, lava from Kilauea has consumed about two dozen homes located miles from the volcano’s crater and about 2,000 people have been evacuated from the danger zone.

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Venus May Once Have Been Habitable, According To NASA

Venus – a hellish planet with an atmosphere of carbon dioxide, almost no water and temperatures of more than 460 degrees Celsius – may once have been habitable, according to Nasa scientists.

Researchers used climate models to calculate that Venus might have had a shallow ocean of liquid water and temperatures that could have allowed life to exist for up to two billion years of its early history.

The atmosphere is 90 times as thick as the air on Earth and scientists had thought this was largely caused by the difference between the two planets’ rate of spin.

A day on Venus lasts 117 Earth days because it spins on its axis at a much slower rate. But recent research showed that Venus could have had an atmosphere similar to the Earth’s today.




The first signs that Venus once had an ocean were discovered by NASA’s Pioneer mission in the 1980s.

Venus is closer to the sun than Earth and receives far more sunlight.

This caused the ocean to evaporate, water-vapour molecules were broken apart into hydrogen and oxygen by ultraviolet radiation and the hydrogen escaped to space.

With no water left on the surface, carbon dioxide built up in the atmosphere and led to a runaway greenhouse gas effect that created present searing heat.

A map of Venus’s surface based on imagery collected by Magellan, Pioneer Venus, and Venera 13 and 14 .

Michael Way, a researcher at Nasa’s Goddard Institute for Space Studies (GISS) in New York, said: “Many of the same tools we use to model climate change on Earth can be adapted to study climates on other planets, both past and present.

Colleague Anthony Del Genio added: “In the GISS model’s simulation, Venus’ slow spin exposes its dayside to the sun for almost two months at a time.

In a statement, Nasa said it was thought that Venus may have had more land than Earth. One of the factors they had to take into consideration was the ancient sun was up to 30 per cent dimmer.

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Why Can’t We Predict When A Volcano Will Erupt?

We started 2016 with a bang. Both Chile and Indonesia saw a clutch of volcanoes erupting after laying dormant for a decade or more.

This followed an eruption in April 2015, when Calbuco volcano in Chile burst back to life after more than 40 years of silence, with experts giving less than two hours of warning.

In an era of global satellite monitoring with proliferating networks of instruments on the ground, why can we still not accurately predict volcanic eruptions?

Volcano scientists have an unprecedented array of tools with which to keep an eye on the world’s many restless and active volcanoes. In many cases, we can watch emerging events from the safe distance of an volcano observatory.

Or, once an eruption has begun, we can observe it in near-real time using satellite feeds and social media. But this isn’t matched by our ability to anticipate what might happen next at a restless but dormant volcano.




New research, however, is providing clues about the best way to look for signals of future volcanic behaviour.

Like medicine, volcanologists can get a clearer sense of the state of a volcano using observations from many other examples around the world.

But if we don’t know the prior history of a particular volcano, and with no way of taking the equivalent of a biopsy from it, our capacity to work out what is going on is always going to be limited.

For example, some volcanoes stay completely quiet and then erupt violently without warning, while others are noisy but have a moment of calm before they erupt. Without prior knowledge, how would we know?

Sampling eruptions

While we can’t yet safely drill into a rumbling volcano, the deposits from past eruptions may contain the information we need about what happened in the build-up to that eruption.

Explosive eruptions typically throw out large quantities of ejecta, the frozen and disrupted remnants of the emptied magma reservoir.

This often includes pumice, a light and frothy rock made of a network of glassy tubes, sheets and strands and a void space that fills with volcanic gas, mainly steam, just before eruption which is then replaced with air.

Other components include crystals of different minerals that grew at depth as the magma cooled and started to solidify, perhaps for decades or centuries.

As the magma cools and freezes into solid rock, the gases remain dissolved in a smaller and smaller amount of melt, until eventually the melt becomes saturated and bubbles of gas start to form.

From this point, the pressure inside the volcano begins to build and eventually, the rocks around the magma chamber crack.

Then the bubbly magma rises through the crack to the surface, starting an eruption.

Bubbles point the way

But how can we find out the point at which the magma starts to grow bubbles? This is where forensic volcanology comes in.

As magmas freeze, the crystals formed at different times will capture snapshots of the state of the reservoir.

With some good fortune, it is sometime possible to go and find these crystals after an eruption, and piece together the sequence of events.

In our new research, my colleagues and I have shown how this approach works at Campi Flegrei, a steaming volcanic field that lies west of Naples and the supposed location of the entrance to the underworld in Roman mythology.

By analysing the composition of one particular mineral called apatite, which grew throughout the long cooling history of the magma, we found that the gas bubbles could only have formed shortly perhaps a few days to months before the eruption itself.

So at this volcano, the best signals of an impending eruption might be a combination of swelling of the ground levels (with changing pressure) and in the gases escaping out of the volcano.

This still doesn’t provide us with a simple way to predict the eruptions of any volcano.

But it does show how taking a forensic look at the deposits of past eruptions at a specific site offer a way to help identify the monitoring signals that will give us clues to future behaviour.

And this moves us a step closer to being able predict when an eruption is likely.

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