Derkachev, A.

Gorbarenko, S.

Hua, Lv. H.

Malakhov, M.

Nikolaeva, N.

Nürnberg, Dirk

Ponomareva, V.

Portnyagin, Maxim

Sakamoto, T.

van den Bogaard, Christel

English

OceanRep

10/14/121/2CONTROL ID: 1460421TITLE: Tephrostratigraphic investigations of the Late Pleistocene-Holocene deposits in thenorthwestern Pacific Ocean and adjacent seas (Okhotsk and Bering)AUTHORS (FIRST NAME, LAST NAME): Alexander Derkachev1, Nataliya Nikolaeva1,Maxim Portnyagin4, 5, Vera Ponomareva3, Sergey Gorbarenko1, Mikhail Malakhov2, DirkNuernberg4, Christel van den Bogaard4, Tatsuhiko Sakamoto6, Hua Hua Lv7INSTITUTIONS (ALL): 1. V.I.Il'ichev Pacific Oceanological Institute, Vladivostok, RussianFederation. 2. North-East Interdisciplinary Science Research Institute, Magadan, Russian Federation. 3. Institute of Volcanology and Seismology, Petropavlovsk-Kamchtskiy, Russian Federation. 4. Helmholtz-Zentrum für Ozeanforschung (GEOMAR), Kiel, Germany. 5. V.I. Vernadsky Institute of Geochemistry and Analytical Chemistry, Moscow, Russian Federation.6. Institute of Biogeosciences, Japan Agency for Marine-Earth Science and Technology, JAMSTEC,Yokosuka, Japan. 7. IFirst Institute of Oceanography, SOA, Quindao, China. ABSTRACT BODY: Ash layers (tephra) in both continental and marine deposits bear informationabout history and nature of volcanic eruptions which could influence climate, processes ofsedimentation, and even cause ecological disasters. Tephra layers of Quaternary age have beenidentified in various marine and continental deposits within the northwestern part of transition zonefrom the Asian continent to the Pacific Ocean. Tephras from the areas adjacent to the JapaneseIslands are better studied while those from the areas farther north including Okhotsk and Bering Seashave received less attention until recently. More than 40 sediment cores were obtained duringnumerous expeditions performed by Russian, German, Japanese and Chinese scientists during the lastfifteen years. We have identified and sampled a total of 74 tephra layers and lenses from these coresincluding 22 layers in the Okhotsk Sea, 14 layers in the Bering Sea, and 38 layers - in thenorthwestern Pacific (Kronotsky Bay and Meiji Seamount). Ages of tephra layers have beenestimated based on age-depth models for the cores developed in the result of litho- andbiostratigraphic studies, paleomagnetic and oxygen-isotope research, and 14C dating. Tephra from allthese layers have been characterized based on morphology of glass shards, optical properties(refractive indices), and chemical composition of glass (major and trace elements) and minerals(major elements). About 3500 precise and consistent electron probe and ~200 LA-ICP-MSanalyses of volcanic glasses and 1200 electron probe analyses of minerals comprise the core of ournew data base. Processing of these data has allowed us to correlate a number of tephra layersbetween the cores in each of the studied regions. Several tephra layers have been correlated betweenthe Bering Sea and Pacific cores. These results permit direct comparisons of the paleoceanologicalrecords over the vast area in the northwestern Pacific domain. Studied tephra layers form the basis ofthe tephrochronological framework for the Quaternary deposits, necessary for correlation of varioussediments, and paleoceanological and paleogeographical reconstructions. This research has allowedus to obtain unique data on the large-scale volcanic eruptions in the Kurile-Kamchatka volcanic arcand identify the periods of enhanced explosive activity. At this stage, the obtained paleovolcanicrecord is more complete than that obtained on land (e.g. Bindeman et al., 2010; Braitseva et al.,1995), and may serve as a basis for estimation of environmental impact of the volcanic eruptions. Afew tephra layers have been correlated between sea cores and on-land sites providing the first linksbetween the marine and terrestrial depositional successions. In the Okhotsk Sea, the areas of ash fallfor some large eruptions from Kamchatka and Kurile Islands volcanoes have been identified that10/14/122/2permits estimations of tephra volumes and eruptions magnitudes. This work was supported by theRussian-German KOMEX and KALMAR Projects, Russian-Japanese (06-05-91576 JP, JSPS)and Russian-Chinese (40710069004, 41076038 NNSF of China, SOA) grants as well as grantsfrom the Russian Foundation for Basic Research (10-05-00160a and 11-05-00506a).KEYWORDS: [8428] VOLCANOLOGY / Explosive volcanism, [8455] VOLCANOLOGY /Tephrochronology, [1105] GEOCHRONOLOGY / Quaternary geochronology.(No Image Selected)(No Table Selected)Additional DetailsPreviously Presented Material: The results were partly published in Deep Sea Research II (2012)and represented on International conferences in Trier, Germany (2011) and Petropavlovsk-Kamchatsky, Russia (2011).Contact DetailsCONTACT (NAME ONLY): Alexander DerkachevCONTACT (E-MAIL ONLY): derkachev@poi.dvo.ruTITLE OF TEAM:

Tephrostratigraphic investigations of the Late Pleistocene-Holocene deposits in the northwestern Pacific Ocean and adjacent seas (Okhotsk and Bering)

Tephrostratigraphic investigations of the Late Pleistocene-Holocene deposits in the northwestern Pacific Ocean and adjacent seas (Okhotsk and Bering)

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