Tuff Schist

The adventures of an unstable geologist

Posts tagged geology

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atlasobscura:

Bowling Ball Beach - Schooner Gulch State Beach, California

At the edge of the Pacific Ocean, the beach at Schooner Gulch State Beach near Mendocino, looks as though its been scattered with oversized bowling balls. Almost perfectly spherical, stones like these have caused wild speculation wherever they’ve been discovered, with answers from aliens to dinosaurs, but the answer is actually simple geology.

Best observed at low tide, the so-called bowling balls are actually a geological phenomena known as “concretion”, sedimentary rock formed by a natural process wherein mineral cements bind grains of sand or stone into larger formations. These boulders are the result of millions of years of concretion and erosion, exposing the hard spheres as the mudstone of the cliffs receded around them.

Explore the rest of Bowling Ball Beach on Atlas Obscura!

Filed under sedementology geology beach

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From Earth Science Picture Of The Day; January 17, 2014:
Tongariro CrossingPhotographer and Summary Author: Ryan Miller
The photo above shows a portion of the Tongariro Alpine Crossing mountain trail on the North Island of New Zealand. This crossing stretches across the Tongariro volcanic complex on the North Island’s Central Plateau. Seen in the background at left center is Mount Ngauruhoe, a parasitic stratovolcano rising to a height of about 7,500 ft (2,290 m). In the Lord of the Rings Trilogy, Mount Ngauruhoe was featured as Mt. Doom. The crossing is approximately 12 mi (19 km) in length and normally takes about seven hours to complete. Photo taken on March 29, 2011.

From Earth Science Picture Of The Day; January 17, 2014:

Tongariro Crossing
Photographer and Summary Author: Ryan Miller

The photo above shows a portion of the Tongariro Alpine Crossing mountain trail on the North Island of New Zealand. This crossing stretches across the Tongariro volcanic complex on the North Island’s Central Plateau. Seen in the background at left center is Mount Ngauruhoe, a parasitic stratovolcano rising to a height of about 7,500 ft (2,290 m). In the Lord of the Rings Trilogy, Mount Ngauruhoe was featured as Mt. Doom. The crossing is approximately 12 mi (19 km) in length and normally takes about seven hours to complete. Photo taken on March 29, 2011.

(via wigmund)

Filed under volcano new zealand geology

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2013 AGU Fall Meeting

Watch out San Francisco; her we come!!!

Keep the beer flowing and never mind those people stopping suddenly on the sidewalk to stare at the stone tiles on the sides of buildings. We’re just admiring the gneiss texture.

Filed under geology geophysics agu american geophysical union

162 notes

bijoux-et-mineraux:

Uvarovite Garnets - Russia

Yes, garnets can be green. Uvarovite is a Calcium Chromium silicate with the usual garnet crystal structure. I’m still looking for some crystals large enough to add to my minerals-that-look-like-dice collection, but have yet to see any sizable specimens outside of a museum or university collection. Does anyone have any suggestions?

bijoux-et-mineraux:

Uvarovite Garnets - Russia

Yes, garnets can be green. Uvarovite is a Calcium Chromium silicate with the usual garnet crystal structure. I’m still looking for some crystals large enough to add to my minerals-that-look-like-dice collection, but have yet to see any sizable specimens outside of a museum or university collection. Does anyone have any suggestions?

(via geologista)

Filed under mineralogy geology garnet