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Hyaloclastic beds in ancient submarine successions: insights from Italy and South Korea

Andrea Di Capua1, Federica Barilaro2,1, Young Kwan Sohn3, Gi-Bom Kim4, Chang Woo Kwon5, Sunyoung Go5, Elena Zanella6, Gianluca Norini1, Roberto Sulpizio7,1, Gianluca Groppelli1

  • Affiliations:  1CNR -- IGAG, Via R. Cozzi 53, 29125 Milano, Italy; 2Department of Biology, Ecology and Earth Sciences, University of Calabria, 87036 Arcavacata di Rende - Cosenza (Italy); 3Department of Geology, Gyeongsang National University, Jinju 52828, Republic of Korea; 4Department of Geological Sciences, Pusan National University, Busan 46241, Republic of Korea; 5Korea Institute of Geoscience and Mineral Resources, 124 Gwahak-ro, Yuseong-gu, Daejeon 34132, Republic of Korea; 6University of Turin, Department of Earth Sciences, Via Verdi 8, 10124, Turin (Italy); 7Dipartimento di Scienze della Terra e Geoambientali, University of Bari, Via Re David, 70125 Bari Italy 

  • Presentation type: Talk

  • Presentation time: Tuesday 14:45 - 15:00, Room R280

  • Programme No: 3.5.7

  • Theme 3 > Session 5

Abstract

Water/lava interactions represent the fundamental mechanism triggering the emplacement of primary volcaniclastic layers in many non-explosive volcanic contexts. Nevertheless, rates of accumulation of such layers during effusive eruptions may be consequence of effusive rate variations. Under this light, this work explores the macro- and microscopic features characterizing two volcano-sedimentary successions exposed, respectively, in Southern Italy (Aci Castello Formation -- Etna volcano) and South Korea (Dodong Basalts -- Ulleung Island), accumulated by the outflow of basaltic melts during the first stage of construction of the Etna and Ulleung volcanoes. Combining fieldwork, petrographic and paleomagnetic analyses, the work proposes to explore mechanisms on the basis of generation and transportation of hyaloclastic particles in submarine contexts. In Aci Castello, basaltic effusion triggered the accumulation of pillow basalts, whereas primary volcaniclastic deposits consist of almost subvertical hyaloclastic layers with basaltic fragments and muddy rip-up clasts in a reddish groundmass. The succession is packaged in a prograding fan-like body. In turn, Dodong Basalts were accumulated as sheet-like basalts all around the basal part of Ulleung Island and are locally interbedded by primary volcaniclastic deposits. Such deposits are composed of fine to coarse grained yellowish particles and loose, cm-long pyroxene crystals. In both cases, macro- and microscopical observations are crucial in the identification of mechanisms at the base of hyaloclastic particles' rate of generation. This work was supported in part by the Italian Ministry of Foreign Affairs and International Cooperation, grant number KR23GR08.