Volcanic Smoke Rings — very rare
Mt. Etna, Italy. 2014.
Have a look at this lovely video produced by the scientists behind Disk Detective with the help of some of the volunteers.
The U.S. Geological Survey has issued a new global geologic map of Mars –the most thorough representation of the Red Planet’s surface. “This map provides a framework for continued scientific investigation of Mars as the long-range target for human space exploration,” according to a USGS press statement. The new map brings together observations and scientific…
For anyone interested in the geology (or, should I say, areology!) of Mars, this fantastic new map has been released, detailing the different properties of the regions of the planet’s surface.
In one of the biggest-ever seismology deployments at an active volcano, researchers are peppering Mount St Helens in Washington state with equipment to study the intricate system of chambers and pipes that fed the most devastating eruption in US history. This month, they will even set off explosions to generate their own seismic waves. The work could inform research into how volcanoes work throughout the Pacific Northwest and in similar geological settings around the world.
Researchers have already explored magma structures beneath volcanoes such as Italy’s Etna and Vesuvius, and an ongoing multidisciplinary project in the Andes targets two volcanoes in Bolivia and Chile where the ground has been rising for about two decades. But the Mount St Helens study is unique because it aims to produce a three-dimensional picture all the way through and beneath the volcano. If all goes well, it may probe as much as 80 kilometres underground — deep enough for scientists to visualize the mountain’s geological origins.
Upper Missouri River Breaks National Monument, Montana — Bob Wick, Instagram Guest Photographer
About the photo: This photo is an example of the use of use of framing to add a sense of intrigue to the image by blocking part of the view – Viewers will look at the person in the “Hole in the Rock” and wonder what that individual is seeing. To access the Hole in the Rock and other amazing photogenic rock formations, one must take a multi-day float trip down the Upper Missouri Wild and Scenic River. You will be following the same route (albeit going downstream) that Lewis and Clark came up on their voyage of discovery. The Upper Missouri River Breaks National Monument hold a spectacular array of plant life, wildlife, unique geological features, endless recreational opportunities and significant historical and cultural values. The 149-mile Upper Missouri National Wild and Scenic River flows through the monument. The land and the rugged, surrounding uplands (commonly call the Missouri Breaks) are defined in part by their history. Learn about float trip and other opportunities at the Missouri Breaks Interpretive Center at 701 7th Street, Fort Benton, Montana.
Camera Settings: Lens focal length: 30mm, aperture: f14, shutter speed: 1/30 second, ISO 100
DID THE VIKINGS USE ICELAND SPAR TO NAVIGATE?
Iceland spar is a clear, transparent, colorless crystallized variety of calcite (calcium carbonate, CaCO3). Large pieces are split along natural cleavage planes to form natural rhombs. Iceland spar is probably best known for exhibiting the optical property of double refraction - so, anything viewed through the crystal appears double. It has many uses, in everything from precision optical instruments to LCD screens, and was even used during WWII to make bombsights. The perfect, flawless, colorless Iceland spar that is used in optical instruments sells for more than $1000 per kg. Historically, the first, best quality, and most abundant source of this clear calcite was in Iceland, which is where it got its name. Recently, Iceland spar has been in the news because of new research that shows that this mineral was almost certainly used by the Vikings for navigation.
Over 1,000 years ago, the Vikings sailed from Scandinavia to America without the use of magnetic compasses, astrolabes, maps or any other known device. Yet they still managed to find their way in spite of the clouds, fog, and long summer twilights characteristic of near Polar Regions. Centuries old Viking legends attribute their navigational success to the use of mysterious, glowing “sunstones” to find the position of the sun and set the ship’s course even on cloudy days. Although still controversial, many researchers now believe that these “magical sunstones” were in fact Iceland spar.
When Iceland spar splits light into two polarized rays, the two different images will have different brightness depending on the polarization. Because sunlight is polarized when it enters the Earth’s atmosphere, it is possible to change the orientation of a piece of Iceland spar to determine the direction of the sun. This is done by moving the crystal until the relative brightness of the two images are equal, which only happens when the crystal is aligned to the sun. This is possible even when the Sun is hiding behind clouds or just below the horizon.
Turbidites are sediments deposited through deep submarine turbidity currents along sloping shelves. They are usually deposited offshore of an active convergent margin wherein tectonic activities could trigger the density-based avalanches.
Lake Natron, Tanzania. This shallow salt lake can reach 60°C/140°F temperatures, and depending on rainfall, the alkalinity can reach a pH of 10.5, almost as alkaline as ammonia. Red-pigmented bacteria thrive under the surface, giving it the deep red color. [1000x679][OS] Unknown photographer via /r/EarthPorn http://ift.tt/1rRNkuu