Eyjafjallajökull
Description:
- Iceland, north of Skógar & west of Mýrdalsjökull
- Covered by an ice cap
- Fissures vents on both sides of the volcano
- Magma Chamber under the mountain
- Erupted 2010
Structure
- elongated structure: shield volcano
- 25 km long from E-W and 20 km wide from N-S
- relatively flat top containing an eliptical summit crater with a diammeter of between 2 and 3 km.
- flanks are heavily eroded and drop off steeply at the edges
- The summit crater and some of the surroundings are glaciated, with a maximum thickness of about 200 m
- Gigjökull glacier extends from a breach in the north crater wall down to near the valley floor
- foundation constructed largely subglacially
Composition
Basalt http://geology.com/rocks/basalt.shtml
- dark-colored
- fine-grained
- igneous rock
- composed mainly of plagioclase and pyroxene minerals
- most commonly forms as an extrusive rock
- lava flow but, also in small intrusive bodies; such as an igneous dike or a thin sill
Andesite http://geology.com/rocks/andesite.shtml
- usually light to dark gray
- weather to various shades of brown
- fine-grained
- igneous rock
- rich in plagioclase feldspar minerals
- extrusive
- moderate viscosity
- forms thick lava flows and domes.
http://www.photovolcanica.com/VolcanoInfo/Eyjafjallaj%C3%B6kull/Eyjafjallaj%C3%B6kull.html
http://davidthompson.typepad.com/davidthompson/2010/04/the-warm-earth.html
Plosky Tolbachik
Description:
- volcanic complex on the Kamchatka Peninsula, east of Russia
- two overlapping, but morphologically dissimilar volcanoes
- on Ostry Tolbachik mountain
- erupted in 2012 from two fissures
- fast flowing basaltic lava, flooding 12miles in one month
- cylinder cone
Structure
- flat-topped shield volcano & a peaked stratovolcano
- The fumarole deposits are rich in exotic minerals
- flat-topped Plosky 3km in diameter
- Tolbachik 3,682 m
Composition
Basalt
Alarsite http://www.webmineral.com/data/Alarsite.shtml#.WKWsBTuLT-g
- aluminium arsenate mineral
- brittle subhedral grains which exhibit trigonal symmetry
- semitransparent, colorless with pale yellow tints and shows a vitreous luster
tolbachite http://webmineral.com/data/Tolbachite.shtml#.WKWslDuLT-g
- Brown, Golden brown
- Fibrous - Crystals made up of fibers.
- moss-like appearance
http://www.photovolcanica.com/VolcanoInfo/Eyjafjallaj%C3%B6kull/Eyjafjallaj%C3%B6kull.html
https://www.airpano.ru/files/Kamchatka-Volcano-Plosky-Tolbachik/2-2
Baatara Gorge Sinkhole
Description:
- Tannourine, Lebanon
- A chasm descending into Mount Lebanon
Structure
- The waterfall drops 255 metres (837 ft) into the Baatara Pothole
- Mount Lebanon range extends along the entire country for about 170 km, parallel to the Mediterranean coast
- Their highest peak is Qurnat as Sawda', at 3,088 m
Composition
Limestone http://geology.com/rocks/limestone.shtml
- sedimentary rock
- composed primarily of calcium carbonate
- commonly forms in clear, warm, shallow marine waters
- an organic sedimentary rock
- forms from the accumulation of shell, coral, algal, and fecal debris
- It can also be a chemical sedimentary rock formed by the precipitation of calcium carbonate from lake or ocean water.
http://www.libanvision.com/tannourine.htm
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