ABNORMALLY HIGH MERCURY CONTENTS IN HYDROGENIC FERROMANGANESE CRUSTS FROM SETH GUYOT (Northwestern Pacific)
P.E. Mikhailik1,2, A.I. Khanchuk1, E.V. Mikhailik1, M.V. Ivanov3, V.A. Rashidov4, N.V. Zarubina1, M.G. Blokhin1, N.N. Barinov1, S.P. Pletnev3
1Far East Geological Institute, Far East Branch of the Russian Academy of Sciences, pr. Stoletiya Vladivostoka 159, Vladivostok, 690022, Russia
2Far East Federal University, ul. Sukhanova 8, Vladivostok, 690950, Russia
3V.I. Ilyichev Pacific Oceanographic Institute, ul. Baltiiskaya 43, Vladivostok, 690041, Russia
4Institute of Volcanology, Far East Branch of the Russian Academy of Sciences, bulv. Piipa 9, Petropavlovsk-Kamchatsky, 683006, Russia
Keywords: Ртуть, железомарганцевые корки, гайоты, Северо-Западная Пацифика, Mercury, ferromanganese crusts, seamount, Northwestern Pacific
Subsection: PETROLOGY, GEOCHEMISTRY, AND MINERALOGY
Abstract
Variations in mercury contents in marine sediments have implications for hydrothermal activity, paleoclimate, depositional environments, and primary bioproduction. Mercury contents reach 148 ppb in hydrogenic ferromanganese crusts on flat-topped seamounts. Such crusts, with up to 4120 ppb Hg, were dredged from the slopes of Seth Guyot in the western Marcus-Wake Seamounts in 1982, during the 13th cruise of RV Vulkanolog. The Seth ferromanganese crusts are of the same origin as hydrogenic Co-rich ferromanganese deposits from seamounts in other oceanic regions. Mercury accumulated in the Cenozoic as Fe-Mn oxyhydroxides in the crusts adsorbed Hg from bottom water. The process was especially rapid during the Pliocene volcanotectonic rejuvenated stage.
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