Volcanic Eruptions in the Sediment Record
Another day of the same old mud. Here is an excerpt from the daily science report from a few days ago: We are still retrieving the same monotonous clay sequence that frequently alternates with dm-sized sandy layers and is sometimes interrupted by ash layers.
Up to now these ash layers could not be related to any eruption and thus we have to wait until we get the geochemical fingerprints for this during post-cruise research.
The back story is that the sedimentologists are excited to see the ash layers. Everyone is bored with the gray green sediment, and it has only been a few days. The ash layers will tell the story of volcanic eruptions. The volcanoes are part of the subduction system, with volcanoes running up and down Central America.
Here is a short video about the ash layers. http://www.youtube.com/watch?v=fLBOsHIfdA4
The ash is not burnt material, but glass fragments that were created during volcanic eruptions. You probably remember the volcanic eruptions of Eyjafjallajokull in Iceland in 2010. It is the same glass particles that stopped all place traffic is what we are finding in the sediments. If you don’t remember this event, check out this site that always has amazing photos of big events. http://www.boston.com/bigpicture/2010/04/more_from_eyjafjallajokull.html
Learn more at http://volcanoes.usgs.gov/images/pglossary/ash.php
(photos by Saneatsu Saito. Stephan Kutterolf is the smiling sedimentologist. Thanks!)