Between a Rock and a Hard Place

Volcanoes

Science Snap (#25): Vesuvius, Andy Warhol

April 21, 2014

Vesuvius by Andy Warhol. 1985. Credit: Gaetano Anzisi

Quite simply, volcanoes are inspiring. I’ve yet to meet someone who disagrees. The majestic volcanic landscape has thus been an inspiration to many an artist and author, whether intentional or not. Furthermore, artwork itself can be a valuable tool to help decipher and understand eruptions and their effects on the climate.

Pictured here is Vesuvius erupting in all its glory and is one of my favourite pieces of “volcanic arc”. Andy Warhol made a few variations on this theme so have a google, take a look around and enjoy (there are not many pictures available on creative commons though so can’t be included here!)

 

 

Science snap (#23): Pacaya Volcano

April 17, 2014
Pacaya

NASA satellite image of the erupting Pacaya volcano, Guatemala. Credit: NASA

Pacaya Volcano, Guatemala, is almost continuously erupting, making it one of Guatemala’s most active volcanoes and a popular tourist destination. The volcano last erupted on March 2, 2014, shown in the image here taken by the MODIS instrument on the Terra satellite. Although the volcano has been kicking off since January, in March Pacaya erupted with small explosions and diffuse ash plumes, causing the opening of a new lava vent. The brown plume is clearly seen in the image and is travelling west, extending beneath the contrasting white clouds.

The Pacaya volcano is a part of the Central American Volcanic Arc, a chain of volcanoes stretching from the northwest to the southeast along the Pacific coast of Central America, formed by the tectonic subduction of the Cocos Tectonic Plate beneath the Caribbean Plate.

 

Source: http://visibleearth.nasa.gov/view.php?id=83278

 

 

Tolbachik – a mineralogist’s paradise

March 17, 2014

Tolbachik is a basaltic volcanic massif lying at the southern end of the Kliuchevskoi group in Kamchatka, Russia. It comprises two overlapping cones: Plosky Tolbachik, a Holocene shield volcano extending to 3 km in diameter; and the older (Pleistocene) Ostry Tolbachik, a sharp-topped stratovolcano reaching some 3,700 m in height.

Tolbachik

Lava flows on the summit of Plosky Tolbachik. Photo credit: Lena Melekhova

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Using garnet geochemistry to investigate the lithospheric mantle beneath northern Tanzania

November 19, 2013

Sorcha McMahon is a third year PhD student in the School of Earth Sciences at the University of Bristol. Sorcha is investigating how strange igneous rocks called carbonatites may have formed, using both natural samples and high-pressure experiments.

As part of my undergraduate MSci course at the University of Cambridge, I carried out a project investigating a collection of thin sections from peridotite xenoliths from northern Tanzania. The main aim of this research was to constrain the petrogenetic evolution of the lithospheric mantle beneath the East African Rift (EAR) and adjacent Tanzanian Craton. Techniques employed included the electron microprobe (EMPA) and LA-ICP-MS to characterise the major and trace element contents of constituent minerals in garnet-bearing lherzolite and harzburgite mantle xenoliths. For the first time globally, we found ultra-depleted pyrope garnets from Lashaine peridotites displaying rare earth element (REE) patterns similar to those of hypothetical garnets proposed to have formed in the subcontinental lithospheric mantle prior to any metasomatism*.

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