Completing the eruptive record of Deception Island (South Shetland Islands, Antarctica) by characterizing ash layers in proximal marine sediments cores

• Main Authors: Polo-Sánchez, A., Hopfenblatt, Joaquin, Geyer, Adelina, Aulinas, M., Ercilla, Gemma, Álvarez-Valero, A. M.
• Other Authors: Ministerio de Economía y Competitividad (España), Agencia Estatal de Investigación (España)
• Format: Conference Object
• Language: English
• Published: European Geosciences Union 2021
• Subjects: Antarctic; The Antarctic; South Shetland Islands; Bransfield Strait; Deception Island; Antarc*; Antarctica
• Online Access: http://hdl.handle.net/10261/259509; https://doi.org/10.5194/egusphere-egu21-2402; https://doi.org/10.13039/501100011033; https://doi.org/10.13039/501100003329

European Geosciences Union (EGU) General Assembly, 19-30 Apr 2021.-- 2 pages.-- Analyzed tephra samples and sediment cores were provided by the rock repository of the Instituto de Ciencias del Mar del CSIC (ICM-CSIC) (http://gma.icm.csic.es/ca/dades).-- This research is part of POLARCSIC and PTIVolcan research initiatives. The chemical and textural characterization of ash layers allows relating them to their volcanic source, provides information regarding an eruptive event and its impact; and pictures more accurate scenarios in case of future activity. Deception Island, located in central Bransfield strait (South Shetland Islands, Antarctica), consists of a horseshoe-shaped composite volcano, whose central part is occupied by a collapse caldera (8.5 x 10 km). It is considered to be among the most active volcanoes in Antarctica and a future eruption is very likely to happen, affecting the military and scientific research stations located nearby. The characterisation of volcanic ash layers found in marine sediment cores outside Deception Island can provide valuable information to: (i) determine the size and explosiveness of past eruptive events, (ii) assess the extent of their related hazards; and (iii) complete the eruption record of the island. Here, we present results of the characterization of the ash layers found on five marine sediment cores (TG-40, 41,43, 48 and 50) drilled proximal to Deception Island (less than 40 km) during the Antarctic Campaign of the MAGIA project (ANT-584/97). The final aim is to trace isochronous tephra horizons between the studied cores and try associating them to their respective eruptive events on the island. First, we carried out a granulometry analysis of each sampled layer and characterized the morphology of the fragments using as parameters: elongation, sphericity, solidity, and length/width ratio. Results obtained indicate that most of the layers are moderate to well sorted coarse ash. Minor amounts of lapilli and fine ash appear in the shallower (0 to 50 cm depth) layers. ...