Posts tagged geology

Velvet Beauty

This is the actual name of this magnificent specimen. It is an important piece, one gotten from a private collection and displayed by a vendor at the Tucson Rock and Gem Show. It was found in 1890 at Bisbee, Arizona, long a world-known site for azurite and malachite as well as copper.
The photo was taken through glass, and the vendor held up a flashlight for me to take this picture. Velvet Beauty can be yours for a mere $25,000. It is the finest specimen I have ever seen of one of my favorite minerals. I believe the chunk weighs about 3 pounds and is about 9” in diameter.
Photo by cobalt123

Velvet Beauty

This is the actual name of this magnificent specimen. It is an important piece, one gotten from a private collection and displayed by a vendor at the Tucson Rock and Gem Show. It was found in 1890 at Bisbee, Arizona, long a world-known site for azurite and malachite as well as copper.

The photo was taken through glass, and the vendor held up a flashlight for me to take this picture. Velvet Beauty can be yours for a mere $25,000. It is the finest specimen I have ever seen of one of my favorite minerals. I believe the chunk weighs about 3 pounds and is about 9” in diameter.

Photo by cobalt123

The Biggest Bang of the 20th Century: The 1912 Eruption of Novarupta in Alaska

[June 6, 2012 marked] the 100th anniversary of the largest eruption of the 20th century, yet many people have never even heard its name. In fact, the name was wrong for almost half a century! What is known as the Novarupta or Katmai eruption of 1912 was huge – ejecting almost 30 cubic kilometers of ash and debris into the atmosphere or along the ground as pyroclastic flows. That represents ~13 cubic kilometers of magma (once you correct for all the air in ash) erupted over the course of ~60 hours. That is a rate of nearly 220 million cubic meters per hour, which is roughly 520 million tonnes per hour – or to put it another way, that is ~5,300 Nimitz-class aircraft carriers per hour. Now that is an eruption!

Read the blow-by-blow of the eruption here.

The Biggest Bang of the 20th Century: The 1912 Eruption of Novarupta in Alaska

[June 6, 2012 marked] the 100th anniversary of the largest eruption of the 20th century, yet many people have never even heard its name. In fact, the name was wrong for almost half a century! What is known as the Novarupta or Katmai eruption of 1912 was huge – ejecting almost 30 cubic kilometers of ash and debris into the atmosphere or along the ground as pyroclastic flows. That represents ~13 cubic kilometers of magma (once you correct for all the air in ash) erupted over the course of ~60 hours. That is a rate of nearly 220 million cubic meters per hour, which is roughly 520 million tonnes per hour – or to put it another way, that is ~5,300 Nimitz-class aircraft carriers per hour. Now that is an eruption!

Read the blow-by-blow of the eruption here.

Arctic Bacteria Help in the Search to Find Life On Jupiter’s Moon Europa

In a fjord in Canada scientists have found a landscape similar to one of Jupiter’s icy moons: Europa. It consists of a frozen and sulphurous environment, where sulphur associated with Arctic bacteria offer clues for the upcoming missions in the search for traces of life on Europa.
It is not easy to find a place on Earth where ice and sulphur come together, supposedly like on Europa, Jupiter’s moon. Nonetheless, this place has been located at Borup Fjord Pass in the Canadian High Arctic. Here the sulphurous yellow emissions contrast with the whiteness of the environment, creating images similar to those captured at Jupiter’s satellite.
US researchers have now verified that the sulphur involved in the life cycle of Arctic microorganisms has some characteristics that could help to detect biological remains on Europa. Large space agencies like NASA and the European Space Agency are already in the process of preparing missions.

Read more here.

Arctic Bacteria Help in the Search to Find Life On Jupiter’s Moon Europa

In a fjord in Canada scientists have found a landscape similar to one of Jupiter’s icy moons: Europa. It consists of a frozen and sulphurous environment, where sulphur associated with Arctic bacteria offer clues for the upcoming missions in the search for traces of life on Europa.

It is not easy to find a place on Earth where ice and sulphur come together, supposedly like on Europa, Jupiter’s moon. Nonetheless, this place has been located at Borup Fjord Pass in the Canadian High Arctic. Here the sulphurous yellow emissions contrast with the whiteness of the environment, creating images similar to those captured at Jupiter’s satellite.

US researchers have now verified that the sulphur involved in the life cycle of Arctic microorganisms has some characteristics that could help to detect biological remains on Europa. Large space agencies like NASA and the European Space Agency are already in the process of preparing missions.

Read more here.

What Happens to All That Volcanic Ash?

If you’ve ever seen an explosive volcanic eruption – either live or on video – you know that there is an awful lot of ash produced. All that magma (well, most of it) that is erupting from the volcano is being fragmented into tiny glass shards that we call “ash” and all that ash is being shot into the air at astounding rates – for very large eruptions, it could be as high as 9,500 kg/s for a VEI 7 eruption. In the end, your average eruption is releasing millions to trillions cubic meters of ash into the atmosphere. Most of it falls near the volcano (within tens of km), but a significant portion can travel far away, drifting in the atmosphere for hundreds, thousands, tens of thousands of kilometers around the globe. That ash becomes the telltale signs of an eruption that may have much of its record erased by future eruptions or by the relentless powers of weathering, erosion and transport
So, how does the ash get spread so far from the site of the eruption? The simplistic view of ash behavior in the atmosphere would suggest that very small (< 30 μm) ash should stay aloft for days to weeks – the settling rate is between 10-1 to 10-3 m/s if you apply Stokes Law to the settling of the ash. However, Rose and others (2011) in Geology point out that in even large eruptions, this fine ash can settle in less than a day. This suggests that fine ash might stick together as it drifts in the plume, thus make larger particles that fall out faster than the initial size might suggest. Now, how these ash particle stick together is an open question that requires cooperation between the volcanological and meteorological communities.
Some of the recent large, ashy eruptions worldwide (such as Chaitén and Puyehue-Cordón Caulle) have allowed volcanologists and atmospheric scientists to examine how ash is distributed during an eruption. This allows for the comparison of models of how ash will spread in the atmosphere with observations of the ash by observatories and satellite monitoring (such as the VAACs). The eruption of Eyjafjallajökull in Iceland spread ash over Europe quite rapidly thanks to its very small particle size, in part caused by the interaction with water during the April 2010 phase of the activity (and likely justified the closure of airspace over Europe). However, the ash varied during the course of the eruption and varied depending on the location in Europe.

Read more here.

What Happens to All That Volcanic Ash?

If you’ve ever seen an explosive volcanic eruption – either live or on video – you know that there is an awful lot of ash produced. All that magma (well, most of it) that is erupting from the volcano is being fragmented into tiny glass shards that we call “ash” and all that ash is being shot into the air at astounding rates – for very large eruptions, it could be as high as 9,500 kg/s for a VEI 7 eruption. In the end, your average eruption is releasing millions to trillions cubic meters of ash into the atmosphere. Most of it falls near the volcano (within tens of km), but a significant portion can travel far away, drifting in the atmosphere for hundreds, thousands, tens of thousands of kilometers around the globe. That ash becomes the telltale signs of an eruption that may have much of its record erased by future eruptions or by the relentless powers of weathering, erosion and transport

So, how does the ash get spread so far from the site of the eruption? The simplistic view of ash behavior in the atmosphere would suggest that very small (< 30 μm) ash should stay aloft for days to weeks – the settling rate is between 10-1 to 10-3 m/s if you apply Stokes Law to the settling of the ash. However, Rose and others (2011) in Geology point out that in even large eruptions, this fine ash can settle in less than a day. This suggests that fine ash might stick together as it drifts in the plume, thus make larger particles that fall out faster than the initial size might suggest. Now, how these ash particle stick together is an open question that requires cooperation between the volcanological and meteorological communities.

Some of the recent large, ashy eruptions worldwide (such as Chaitén and Puyehue-Cordón Caulle) have allowed volcanologists and atmospheric scientists to examine how ash is distributed during an eruption. This allows for the comparison of models of how ash will spread in the atmosphere with observations of the ash by observatories and satellite monitoring (such as the VAACs). The eruption of Eyjafjallajökull in Iceland spread ash over Europe quite rapidly thanks to its very small particle size, in part caused by the interaction with water during the April 2010 phase of the activity (and likely justified the closure of airspace over Europe). However, the ash varied during the course of the eruption and varied depending on the location in Europe.

Read more here.

Kilauea, Hawaii

Lava flows on the East Rift Zone coastal plain of Kilauea, seen on May 4, 2012. The budding toes of pahoehoe flows are clearly seen in the foreground of the image. (Image Courtesy of USGS/HVO.)

Kilauea, Hawaii

Lava flows on the East Rift Zone coastal plain of Kilauea, seen on May 4, 2012. The budding toes of pahoehoe flows are clearly seen in the foreground of the image. (Image Courtesy of USGS/HVO.)

Ten Most Dangerous Volcanoes on the Globe

1.  Sakura-jima. Japan.  Since 1955 Sakurajima the stratovolcano in Kyūshū, Japan, often called the Vesuvius of the east, has been erupting almost constantly. Due to its location in a densely populated area, the volcano is considered to be one of the world’s most dangerous. The city of Kagoshima is inhabited by almost 700,000 residents and lies just a few kilometres from the mount. The city has even built special shelters where people can take refuge from falling debris. The volcano’s last eruption took place in March 2009, sending debris up to 2 km away.

2.  Etna. Italy. Mount Etna is Europe’s most active and tallest (3,300 m /10,900 ft) volcano and its potential for destruction is huge. Etna’s constant state of activity is a serious threat to people living in the villages and towns of Sicily. Its most dangerous eruption occurred in 1669, when lava destroyed many villages around the volcano’s base and “swallowed” part of Catania, an ancient town on the east cost of Sicily. In 1992 two streams of lava threatened Zafferana, a municipality inhabited by around 8,000 people.

3.  Kilauea. Hawaii (U.S.). Kilauea, the world’s most active volcano located on the Big Island of Hawaii, for many years has been considered fairly gentle, as relatively few people have been killed following its explosions. Recently, however, the scientists revealed Kilauea’s deadly face. Apparently, the volcano has an extensive layer of ash and rock called tephra that can be blasted high enough to be a hazard to passenger airplanes. The golf ball-size rocks can be thrown 17 kilometres (11 miles) out. The last time tephra erupted was between 500 and 200 years ago.

4. Cotopaxi. Ecuador. Cotopaxi, one of the tallest active volcanoes in the world, reaching a height of 5,897 m (19,347 ft), is a part of the Pacific Ring of Fire, a chain of volcanoes around the Pacific plate. Since 1783 the mount has erupted more than 50 times, posing a serious threat to the nearby cities and villages. Quito, the capital of Ecuador with around 1 million inhabitants, is located 60 km south and Latacunga, a historical town that has already been destroyed four times by earthquakes is 25 km northeast.

5.  Vesuvius. Italy. The legendary Mount Vesuvius sitting on the beautiful coast of the Bay of Naples in Italy has already proven that its destructive capabilities are enormous. In AD 79 a huge explosion wiped out the Roman cities of Pompeii and Herculaneum, killing up to 25,000 people. Vesuvius is ultra dangerous not only because there are 3 million people living nearby, but also due to the fact that its quiescence period has already been very long. Apparently, the longer the quiescence period, the stronger and more explosive the renewal of Vesuvius’ activity will probably be. In the past the mount’s eruptions were so violent that the whole of southern Europe was blanketed by ash.

6.  Merapi. Indonesia. Called the Mountain of Fire in Indonesian, Merapi is the most dangerous volcano in the country, erupting roughly once a decade. Since the 16th century it has been erupting regularly and causing serious threat to people inhabiting the surrounding areas. The violent mountain is located very close to the city of Yogyakarta, and some villages are situated as high as 1,700 m on the flanks of the volcano. In 2006, around 5,000 people were killed and 200,000 left homeless due to the earthquakes that followed Merapi’s eruption.

7.  Nyiragong. Congo. Nyiragongo and nearby Nyamuragira in Congo, Africa, are jointly responsible for 40% of the historical volcanic eruptions on the continent. Apparently, nowhere else on the globe does such a steep-sided stratovolcano contain a lake of such fluid lava like Nyiragongo. In 1977, the lava flowed down the flanks of the mount killing up to 100 people, though some reports point to about several thousand people. In 2002, the volcano erupted again, reaching the city of Goma, where at least 15% buildings were destroyed, leaving 120,000 people homeless and killing around 45 citizens.

8.  Popocatepetl. Mexico.  Another natural-born killer is Popocatepetl, a glacier-covered volcano situated only 70 km from Mexico City. Rising to around 5,400 (17,800 ft) above sea level, the eruption of “the Smoking Mountain” could be a serious threat not only to the capital city (inhabited by fairly 9 million people) but also to other towns and villages located very close to it. Popocatepetl is one of the most violent volcanoes in the country, having had around 20 huge eruptions since the 16th century. In 2000, tens of thousands of people were evacuated just before the volcano exploded and caused enormous glacial melting.

9.  Mount Teide. Spain. The world’s third largest volcano (from its base), Mount Teide, is located on Tenerife, the Canary Islands. Although Teide is currently dormant, further eruptions are possible in the near future, including the risk of pyroclastic flows and surges similar to those that occurred at Merapi or Mount Vesuvius in Italy. Due to Teide’s proximity to several large towns and resorts, the mount was designated one of the Decade Volcanoes by the International Association of Volcanology and Chemistry, with the implication that it’s currently one of the world’s most dangerous volcanoes.

10.  Mount Rainier. Washington (U.S). The peacefully-looking Mount Rainer is in fact an active volcano that has the potential to devastate virtually all areas surrounding its base. It is located around 87 km southeast of Seattle, a major city on the West Coast of the USA. Despite the fact that the most recent recorded eruption took place at the end of the 19th century, lahars (a type of mudflow or landslide) pose serious risk to many communities that lie atop older lahar deposits. Such mudflows can even reach parts of downtown Seattle and cause tsunami in Puget Sound and Lake Washington.

Source: Ten Most Dangerous Volcanoes on the Globe

Thawing Arctic Cryosphere Releases Trapped Methane
A recent study shows that methane gas thought to be permanently trapped under ice is now being released during melting periods.

Using radioactive dating of the carbon-14 isotope, Anthony and her team determined “ancient “ methane was being released from many of the gas seeps, possibly generated from natural gas or coal deposits underneath the water. Other sites were found to be releasing “younger” methane from the period known as the Little Ice Age, around 1500 to 1800.

In this image:  Methane-induced melt-hole on a frozen lake in the Brooks Range in Alaska in April of 2011. Credit: Katey Walter Anthony
Read more here.

Thawing Arctic Cryosphere Releases Trapped Methane

A recent study shows that methane gas thought to be permanently trapped under ice is now being released during melting periods.

Using radioactive dating of the carbon-14 isotope, Anthony and her team determined “ancient “ methane was being released from many of the gas seeps, possibly generated from natural gas or coal deposits underneath the water. Other sites were found to be releasing “younger” methane from the period known as the Little Ice Age, around 1500 to 1800.

In this image:  Methane-induced melt-hole on a frozen lake in the Brooks Range in Alaska in April of 2011. Credit: Katey Walter Anthony

Read more here.

Emerald Lakes.  I&#8217;ve always wanted to travel to New Zealand &#8212; so many geological wonders.  This photo, in particular, is stunning.  Take a look at this travel blog entry for more incredible photos. 

Emerald Lakes.  I’ve always wanted to travel to New Zealand — so many geological wonders.  This photo, in particular, is stunning.  Take a look at this travel blog entry for more incredible photos. 

Be careful where you put those fossils. Turns out fossil hunting has other dangers besides sunburn and slips and falls.  Many fossils are filled with highly enriched uranium. 

How does a fossil made of bone get get turned into a fossil made of uranium?
It&#8217;s actually part of the same process that turns it into a fossil in the first place. Organic material gets buried in sediment, but it doesn&#8217;t get dried or preserved. Instead the organic material is eaten away and replaced by minerals that crystalize along the tiny pores that form in the organic material. Uranium combines with oxygen to form uranium oxides, and these dissolve in water. They flow wherever water flows, including through sediment. The water wore away at the porous organic material. The uranium oxides precipitated uranium so it lined the pores, replacing the bone or bark with rock. What was left was a fossil made of large amounts of uranium.

Read more here.  And keep those fossils away from your sensitive areas!

Be careful where you put those fossils. Turns out fossil hunting has other dangers besides sunburn and slips and falls.  Many fossils are filled with highly enriched uranium. 

How does a fossil made of bone get get turned into a fossil made of uranium?

It’s actually part of the same process that turns it into a fossil in the first place. Organic material gets buried in sediment, but it doesn’t get dried or preserved. Instead the organic material is eaten away and replaced by minerals that crystalize along the tiny pores that form in the organic material. Uranium combines with oxygen to form uranium oxides, and these dissolve in water. They flow wherever water flows, including through sediment. The water wore away at the porous organic material. The uranium oxides precipitated uranium so it lined the pores, replacing the bone or bark with rock. What was left was a fossil made of large amounts of uranium.

Read more here.  And keep those fossils away from your sensitive areas!

Thirsty, anyone? This amazing illustration from the U.S. Geological Survey shows just how little water on earth there actually is.

This picture shows the size of a sphere that would contain all of Earth&#8217;s water in comparison to the size of the Earth. The blue sphere sitting on the United States, reaching from about Salt Lake City, Utah to Topeka, Kansas, has a diameter of about 860 miles (about 1,385 kilometers) , with a volume of about 332,500,000 cubic miles (1,386,000,000 cubic kilometers). The sphere includes all the water in the oceans, seas, ice caps, lakes and rivers as well as groundwater, atmospheric water, and even the water in you, your dog, and your tomato plant.

Read more here.

Thirsty, anyone? This amazing illustration from the U.S. Geological Survey shows just how little water on earth there actually is.

This picture shows the size of a sphere that would contain all of Earth’s water in comparison to the size of the Earth. The blue sphere sitting on the United States, reaching from about Salt Lake City, Utah to Topeka, Kansas, has a diameter of about 860 miles (about 1,385 kilometers) , with a volume of about 332,500,000 cubic miles (1,386,000,000 cubic kilometers). The sphere includes all the water in the oceans, seas, ice caps, lakes and rivers as well as groundwater, atmospheric water, and even the water in you, your dog, and your tomato plant.

Read more here.

Greater Insight Into Earthquake Cycles

For those who study earthquakes, one major challenge has been trying to understand all the physics of a fault &#8212; both during an earthquake and at times of &#8220;rest&#8221; &#8212; in order to know more about how a particular region may behave in the future. Now, researchers at the California Institute of Technology (Caltech) have developed the first computer model of an earthquake-producing fault segment that reproduces, in a single physical framework, the available observations of both the fault&#8217;s seismic (fast) and aseismic (slow) behavior.
This image shows an array of geodetic instruments at the surface of Earth and activity that was modeled on the fault below. The yellow colors indicate the highest speeds of slippage between plates along the San Andreas Fault. The reddish colors represent slower seismic speeds and the bluish colors indicate slippage at velocity close to the long-term advance of the San Andreas Fault. The dark color indicates a portion of the fault where the velocity is so small that it appears completely locked. (Credit: Sylvain Barbot / Caltech)

Read more here.

Greater Insight Into Earthquake Cycles

For those who study earthquakes, one major challenge has been trying to understand all the physics of a fault — both during an earthquake and at times of “rest” — in order to know more about how a particular region may behave in the future. Now, researchers at the California Institute of Technology (Caltech) have developed the first computer model of an earthquake-producing fault segment that reproduces, in a single physical framework, the available observations of both the fault’s seismic (fast) and aseismic (slow) behavior.

This image shows an array of geodetic instruments at the surface of Earth and activity that was modeled on the fault below. The yellow colors indicate the highest speeds of slippage between plates along the San Andreas Fault. The reddish colors represent slower seismic speeds and the bluish colors indicate slippage at velocity close to the long-term advance of the San Andreas Fault. The dark color indicates a portion of the fault where the velocity is so small that it appears completely locked. (Credit: Sylvain Barbot / Caltech)

Read more here.


Burgess Shale, British Columbia

Burgess Shale, British Columbia

Giant Eruptions from Yellowstone Caldera May Have Taken Millennia

Let’s get one thing straight about the current rash of news about Yellowstone and its eruptions: really, nothing much has changed. Sure, a lot of news media took the angle that a shocking new study shows that Yellowstone erupts more often than we might have thought and, yes, we’re all doomed and such. However, if you look at the new findings (and pause to think about it), very little has fundamentally changed about our understanding of the giant caldera in western Wyoming.

Read more here.

Giant Eruptions from Yellowstone Caldera May Have Taken Millennia

Let’s get one thing straight about the current rash of news about Yellowstone and its eruptions: really, nothing much has changed. Sure, a lot of news media took the angle that a shocking new study shows that Yellowstone erupts more often than we might have thought and, yes, we’re all doomed and such. However, if you look at the new findings (and pause to think about it), very little has fundamentally changed about our understanding of the giant caldera in western Wyoming.

Read more here.

On Earthquakes, Eruptions and the Moon 

We see the interaction of the Earth’s surface with the Moon’s gravity (and to some extent the Sun’s) with the tides in the oceans. Water has low viscosity so the tidal tugging of the moon as it rotates around the Earth sloshes the oceans back and forth to create our tides. One could imagine that the Earth’s crust/mantle/core might feel some of that gravitational interaction as well – and they do. John Vidale, a seismologist at the University of Washington, mentions that during full and new moons – when the moon is oriented between or opposite the Earth and the sun – there is potentially as much as a 1% increase in earthquake activity worldwide (and a slightly higher effect on volcanic activity).

Read more here.

On Earthquakes, Eruptions and the Moon

We see the interaction of the Earth’s surface with the Moon’s gravity (and to some extent the Sun’s) with the tides in the oceans. Water has low viscosity so the tidal tugging of the moon as it rotates around the Earth sloshes the oceans back and forth to create our tides. One could imagine that the Earth’s crust/mantle/core might feel some of that gravitational interaction as well – and they do. John Vidale, a seismologist at the University of Washington, mentions that during full and new moons – when the moon is oriented between or opposite the Earth and the sun – there is potentially as much as a 1% increase in earthquake activity worldwide (and a slightly higher effect on volcanic activity).


Read more here.