Tuff Schist

The adventures of an unstable geologist

108 notes

atomstargazer: Tata Sabaya Volcano Tata Sabaya, a volcano located in the Altiplano region of Bolivia, rises to a summit elevation of 5,430 meters (17,800 feet) above sea level. While its current form is that of a youthful stratovolcano, the regional geological evidence indicates an older, eventful history. Prior to 12,000 years ago, a large debris avalanche was formed by the collapse of the ancestral Tata Sabaya volcano. Debris from the avalanche swept into the nearby Salar de Coipasa, significantly changing its northwestern coastline. The timing of the event was obtained from tufa deposits formed on debris islands during a high stand of the Coipasa lake. The sequence illustrates the geological principle of crosscutting, in that the debris avalanche had to have occurred before the tufa deposits were formed in the lake.

atomstargazer:

Tata Sabaya Volcano

Tata Sabaya, a volcano located in the Altiplano region of Bolivia, rises to a summit elevation of 5,430 meters (17,800 feet) above sea level. While its current form is that of a youthful stratovolcano, the regional geological evidence indicates an older, eventful history.

Prior to 12,000 years ago, a large debris avalanche was formed by the collapse of the ancestral Tata Sabaya volcano. Debris from the avalanche swept into the nearby Salar de Coipasa, significantly changing its northwestern coastline. The timing of the event was obtained from tufa deposits formed on debris islands during a high stand of the Coipasa lake. The sequence illustrates the geological principle of crosscutting, in that the debris avalanche had to have occurred before the tufa deposits were formed in the lake.

(via fyeahgeology)

27 notes

distant-traveller: Saturn’s rings seen sideways Saturn’s rings are actually very thin. This picture from the Hubble Space Telescope was taken on August 6, 1995 when the rings lined up sideways as seen from Earth. Saturn’s largest moon Titan is seen on the left, and Titan’s shadow can be seen on Saturn’s cloud tops! Titan itself looks a brownish color because of its thick atmosphere. Four other moon’s of Saturn can be seen just above the ring plane, which are, from left to right: Mimas, Tethys, Janus, and Enceladus. If you look carefully, you will note that the dark band across the planet is actually the shadow of the rings, and is slightly displaced from the real rings - which are best seen away from the planet. Saturn’s rings are not solid - they are composed of ice chunks which range in size from a grain of sand to a house. Image credit: Erich Karkoschka (University of Arizona Lunar & Planetary Lab) and NASA

distant-traveller:

Saturn’s rings seen sideways

Saturn’s rings are actually very thin. This picture from the Hubble Space Telescope was taken on August 6, 1995 when the rings lined up sideways as seen from Earth. Saturn’s largest moon Titan is seen on the left, and Titan’s shadow can be seen on Saturn’s cloud tops! Titan itself looks a brownish color because of its thick atmosphere. Four other moon’s of Saturn can be seen just above the ring plane, which are, from left to right: Mimas, Tethys, Janus, and Enceladus. If you look carefully, you will note that the dark band across the planet is actually the shadow of the rings, and is slightly displaced from the real rings - which are best seen away from the planet. Saturn’s rings are not solid - they are composed of ice chunks which range in size from a grain of sand to a house.

Image credit: Erich Karkoschka (University of Arizona Lunar & Planetary Lab) and NASA

(via circuitdesign)

292 notes

ikenbot: Chondrites and Chondrules Chondrites are stony meteorites. They’re the most common and probably the most fascinating type of meteorite. The meteor/meteorite that broke windows in the Russian city of Chelyabinsk this past February was a stony chondrite. The composition of chondrites is very similar to the composition of the Sun, except that they’re lacking hydrogen and helium. So, if you’d like to hold a piece of the Sun in your palm, chondrites are about as close as you can get. Their name is derived from the chondrules (spherical inclusions) observed in most of them. Chondrules are only found in meteorites. They’re over 4 billion years old — older than the Earth and other planets. Scientists previously identified meteorites by the crystals found within chondrules, but later they realized that chondrules may recrystallize during weathering processes once they reach the Earth’s surface. Sometimes a broken face of a meteorite is weathered in such a way that 3-D chondrules are seen (above at upper right corner). However, chrondules can be more easily studied by cutting the parent chrondite into slices. Shown at center is a a microscopic image of a 3 cm slice of a chondrite that was found in northwest Africa. — Mila Zinkova

ikenbot:

Chondrites and Chondrules

Chondrites are stony meteorites. They’re the most common and probably the most fascinating type of meteorite. The meteor/meteorite that broke windows in the Russian city of Chelyabinsk this past February was a stony chondrite.

The composition of chondrites is very similar to the composition of the Sun, except that they’re lacking hydrogen and helium. So, if you’d like to hold a piece of the Sun in your palm, chondrites are about as close as you can get. Their name is derived from the chondrules (spherical inclusions) observed in most of them. Chondrules are only found in meteorites.

They’re over 4 billion years old — older than the Earth and other planets. Scientists previously identified meteorites by the crystals found within chondrules, but later they realized that chondrules may recrystallize during weathering processes once they reach the Earth’s surface. Sometimes a broken face of a meteorite is weathered in such a way that 3-D chondrules are seen (above at upper right corner). However, chrondules can be more easily studied by cutting the parent chrondite into slices. Shown at center is a a microscopic image of a 3 cm slice of a chondrite that was found in northwest Africa. — Mila Zinkova

140 notes

earth-phenomenon: Hamilton Pool Preserve is a natural pool that was created when the dome of an underground river collapsed due to massive erosion thousands of years ago. The pool is located near Austin, Texas, United States.

earth-phenomenon:

Hamilton Pool Preserve is a natural pool that was created when the dome of an underground river collapsed due to massive erosion thousands of years ago. The pool is located near Austin, Texas, United States.

(via fyeahgeology)

666 notes

mysticplaces:

Photos of the geological formations in the Afar Depression | Ethiopia & Djibouti

In March 2011 George traveled to the Afar Depression in Ethiopia and Djibouti, bring his motorized paraglider to take aerial photographs. The area is probably the most geologically active area in the world; with one of the few permanent lave lakes and frequent earthquakes. Most of the Afar Depression (also known as the Danakil Depression) is below sea level, and it contains the lowest point in Africa, Lake Assale in Djibouti, which is 150 meters below sea level. The lake is also the second saltiest body of water on earth, even saltier than the Dead Sea. The region is home to the semi-nomadic Afari people who eek out a living with goats, camels, and harvesting salt in one of the hottest environments on earth.

2,446 notes

fuckyeahcrystals: Epidote, Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH). The anisotropy, or directional asymmetry, of epidote causes the stone to appear different colors from different directions. The crystal structure bends light differently depending on the path, appearing to you as a color change. This picture shows a bluish-green for the crystals on the left, and a more yellow-green on the right.

fuckyeahcrystals:

Epidote, Ca2Al2(Fe3+;Al)(SiO4)(Si2O7)O(OH).

The anisotropy, or directional asymmetry, of epidote causes the stone to appear different colors from different directions. The crystal structure bends light differently depending on the path, appearing to you as a color change.

This picture shows a bluish-green for the crystals on the left, and a more yellow-green on the right.