Friday, March 2, 2012

Eruption!! - Geo 186

GEO 186 
Vesicular Basalt
Class: Rocks
Location: El Salvador

And we're back! After a two and a half month hiatus, the Sholesonian is back with a bang - or rather volcanic eruption! Things have been hectic around here, but fear not the museum has been constantly growing. So here we have the first post of 2012 and expect many more to come!

Our friend Kayla, who has been an integral part to our arachnology and entomology department, kindly donated this volcanic rock - hailing all the way from El Salvador. This chunk of solidified lava comes from Izalco, a volcano on the western coast of El Salvador. You may not have heard of Izalco before, but it was one of the most active volcanoes in North America, with frequent eruptions from its birth in 1770 up until 1966. It erupted so many times in its 200 year reign, that sailors would use the bright light as a beacon, earning it the name "Lighthouse of the Pacific." 

Izalco is known as a stratovolcano which means that it is built up of layers of lava and rock fragments and usually erupt in an explosive manner causing alarm and unfortunately deaths. You can see in the following photograph from the Smithsonian National Museum of Natural History, that the volcano towers in contrast above the lush Salvadorian jungle. And despite being older than the United States, this is El Salvador's youngest volcano - but has lied dormant since the sixties. It is at an elevation of 6,398 feet (1950 m) which is approximately one and quarter miles above sea level.  The rock itself is a vesicular olivine basalt (vesicular means that it's porous like pumice) and was collected in 2003. Enjoy!

Photo: Smithsonian National Museum of Natural History

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