Discovery of a 200 meter thick layer of volcanic ash in the Aegean Sea laid down by submarine flows that traveled more than 140 km from the source volcano
Scientists Abigail Metcalfe, Tim Druitt and colleagues from the International Ocean Discovery Program (IODP) Expedition 398 ‘Hellenic Arc Volcanic Field’ have found a 200-m-thick ‘megabed’ of volcanic ash buried in the submarine basins of the Hellenic Volcanic Arc, northeast of Santorini in Greece. The ash deposit, described in Science Advances (August 13th) derives from the 161,000 year old Kos Plateau Tuff eruption of the Kos Volcano in the eastern sector of the volcanic arc. Flows of volcanic ash from the eruption entered the sea and travelled across the sea floor for over 140 km westwards parallel to the volcanic arc, destroying marine ecosystems and laying down a huge bed of volcanic ash in deep seafloor troughs. The discovery shows that large volcanic eruptions in marine environments can remodel seafloor landscapes and destroy marine biota on regional scales in short-lived, catastrophic events.
SCIENTIFIC OPERATIONS:
The deep-drilling expedition was conducted by the JOIDES Resolution Science Operator (JRSO) as part of the IODP. The IODP was a multidecadal, international research program supported by 22 nations, with the goal of exploring Earth’s history and structure recorded in seafloor sediments and rocks and monitoring sub-seafloor environments. Expedition 398 sailed with 32 scientists from 9 countries, with expertise in a range of geoscience disciplines.
MORE INFORMATION:
About the expedition – IODP JRSO • Expeditions • Hellenic Arc Volcanic Field (tamu.edu)
About the research program – www.iodp.org
Cartoon showing the eruption of the Kos Volcano 161,000 years ago. The pyroclastic currents from the eruption enter the sea and transform by entrainment of sea water into flowing suspensions of volcanic ash and water (‘turbidity current’). These then travel across the sea floor over 140 kilometers westwards to the submarine basins northeast of Santorini. Pyroclastic currents also travel across land, and volcanic ash is blown eastwards by atmospheric winds. The numbers give the volumes of ash dispersed by each process.
