Between a Rock and a Hard Place

Science snap (#23): Pacaya Volcano

Elspeth Robertson April 17, 2014

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

Science Snap (#21): Diatoms

Charly Stamper March 13, 2014

KT Cooper is a PhD student in the School of Earth Sciences at the University of Bristol. A carbonate geochemist by training, she has just returned from a three-month secondment to Houston, Texas, USA working with Exxon Mobil.

When you start looking at things at a microscopic level, everything starts to look a little alien. Minerals assemblages can look like the landscapes of far off planets and microbes can look like their inhabitants. One such type of alien looking microscopic life form are diatoms.

Diatom images showing the variability in their beautiful morphology. Photo credit: Kate Hendry

Diatoms are type of algae and their colonies generate the strangest of shapes; think of them as nature’s 3D spirographs. Their cell walls are composed of silica and they can be found in many aquatic environments, from the oceans to freshwaters. Diatoms can be used to inform scientists about the environment in which they grew and how this may have been altered due to climate change. But for me, it’s just interesting to see the huge variability in their morphology.

Diatom found on a sample of limestone left in situ in a blue hole in the Bahamas. Photo Credit: KT Cooper

Diatom found on a sample of limestone from a blue hole in the Bahamas. Photo Credit: KT Cooper

Science Snap #21: Nash Point, Vale of Glamorgan, Wales

Charly Stamper March 6, 2014

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.

Dramatic view of Nash Point on a Winter’s Day. Photo credit: Sorcha McMahon.

Nash Point is a picturesque headland along the coastline of the Vale of Glamorgan, consisting of near-vertical cliffs of limestone and mudstone. Strata are of Blue Lias age, and at low tide the exposed shore platform reveals indicative fossils including tiny ammonites.

Local towns of St. Donats or Llantwit Major are convenient bases for the short walk along the coastline, and the walk covers part of the impressive Glamorgan Heritage Coast path. The site itself can be accessed from the cliff tops, and is a short distance from Nash Point lighthouse. This was the last manned lighthouse in Wales (it became automated in 1998), and is now open to the public.

Fossil hunting provided entertainment during the day trip to Nash Point, just 40 minutes drive from Cardiff.
Photo credit: Sorcha McMahon.

Biologist friends enjoyed the geological site of interest!
Photo credit: Sorcha McMahon.

Science Snap (#20): Sentinal-1A Dress Rehearsal

Elspeth Robertson February 27, 2014

On the 3rd April 2014 the new satellite Sentinel-1 will be launched from French Guinea into space. It’s the satellite that has the InSAR community pretty excited as it will provide free Earth Observation data covering nearly all the world’s volcanoes.

Once the satellite is launched and is sat in its correct orbit, it has to “perform a complicated dance routine to unfold its large solar wings and radar antenna“. The ESA video below shows a fast motion test run of this unfloding in the cleanroom at Thales Alenia Space in Cannes, France.

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Copyright: ESA