1. Kolumbo submarine volcano (Greece): An active window into the Aegean subduction system
- Author
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Antonio Caracausi, Danai Lampridou, Manolis Mandalakis, Antonios Magoulas, Paraskevi N. Polymenakou, Andrea Luca Rizzo, Alain Castillo, Valérie Chavagnac, Georgios Kotoulas, Paraskevi Nomikou, Rizzo, A, Caracausi, A, Chavagnac, V, Nomikou, P, Polymenakou, P, Mandalakis, M, Kotoulas, G, Magoulas, A, Castillo, A, and Lampridou, D
- Subjects
event.disaster_type ,geography ,Multidisciplinary ,geography.geographical_feature_category ,010504 meteorology & atmospheric sciences ,Subduction ,Volcanic arc ,Geochemistry ,Volcanology ,Volcanism ,010502 geochemistry & geophysics ,01 natural sciences ,Mantle (geology) ,Article ,Volcanic Gases ,Volcano ,13. Climate action ,Geodynamic ,Subaerial ,event ,Submarine volcano ,Geology ,0105 earth and related environmental sciences - Abstract
Submarine volcanism represents ~80% of the volcanic activity on Earth and is an important source of mantle-derived gases. These gases are of basic importance for the comprehension of mantle characteristics in areas where subaerial volcanism is missing or strongly modified by the presence of crustal/atmospheric components. Though, the study of submarine volcanism remains a challenge due to their hazardousness and sea-depth. Here, we report 3He/4He measurements in CO2–dominated gases discharged at 500 m below sea level from the high-temperature (~220 °C) hydrothermal system of the Kolumbo submarine volcano (Greece), located 7 km northeast off Santorini Island in the central part of the Hellenic Volcanic Arc (HVA). We highlight that the mantle below Kolumbo and Santorini has a 3He/4He signature of at least 7.0 Ra (being Ra the 3He/4He ratio of atmospheric He equal to 1.39×10−6), 3 Ra units higher than actually known for gases-rocks from Santorini. This ratio is also the highest measured across the HVA and is indicative of the direct degassing of a Mid-Ocean-Ridge-Basalts (MORB)-like mantle through lithospheric faults. We finally highlight that the degassing of high-temperature fluids with a MORB-like 3He/4He ratio corroborates a vigorous outgassing of mantle-derived volatiles with potential hazard at the Kolumbo submarine volcano.
- Published
- 2016