RV SONNE Fahrtbericht / Cruise Report SO249 BERING – Origin and Evolution of the Bering Sea: An Integrated Geochronological, Volcanological, Petrological and Geochemical Approach, Leg 1: Dutch Harbor (U.S.A.) - Petropavlovsk-Kamchatsky (Russia), 05.06.2016 - 15.07.2016, Leg 2: Petropavlovsk-Kamchatsky (Russia) - Tomakomai (Japan), 16.07.2016 - 14.08.2016

• Other Authors: Werner, Reinhard, Hoernle, Kaj, Hauff, Folkmar, Portnyagin, Maxim, Yogodzinski, Gene, Ziegler, Alexander
• Format: Report
• Language: English
• Published: GEOMAR Helmholtz-Zentrum für Ozeanforschung 2016
• Subjects: Bering Sea; Pacific; Petropavlovsk; Petropavlovsk-Kamchatsky; Kamchatka
• Online Access: https://oceanrep.geomar.de/id/eprint/34425/; https://oceanrep.geomar.de/id/eprint/34425/6/geomar_rep_ns_30_2016%281%29.pdf; https://doi.org/10.3289/GEOMAR_REP_NS_30_2016

The R/V SONNE expedition SO-249 is part of the research project BERING, conducted in the framework of the Russian-German Agreement on Marine and Polar Research and in close cooperation with U.S. American colleagues. The overarching goal of BERING is to elucidate the magmatic and tectonic evolution of the Bering Sea and its margins over the past ≥50 m.y. In particular, BERING investigates the physical and chemical conditions that control the development of subduction zones, including subduction initiation, evolution of mature arc systems, and the impact of subduction volcanism on the environment. R/V SONNE cruise SO- 249 BERING conducted geological, morphological, and biological studies in the in western the Aleutians, the Pacific seafloor subducting beneath the Aleutians and northern Kamchatka, and in the western Bering Sea. Besides extensive multi-beam mapping and sediment echo-sounder profiling, total of 150 dredge hauls have been conducted on the two legs of cruise SO-249. Of these, 91 delivered massive magmatic and/or metamorphic rocks, 34 volcaniclastic rocks including breccias containing lava fragments, 64 sedimentary rocks, and 19 Mn-Fe-Oxide crusts and nodules. No equipment was lost or seriously damaged. SO-249 achieved its major goals and the SO-249 sample set represents the most detailed sampling of the working areas to date. The on shore work program at Russian, German, and U.S.-American institutions includes geochronological, petrological and geochemical studies on igneous samples obtained during the cruise. The results of BERING will be integrated with those of previous campaigns (e.g. KOMEX, KALMAR), and work carried out within the World Oceans and GeoPRISMS initiatives. The main goal of biological sampling was to survey the benthic biodiversity in the study area. In addition, fresh specimens pertaining to specific taxa (Cnidaria, Brachiopoda, Cephalopoda, Echinodermata) were collected to supplement ongoing research projects. Of the 150 dredges taken, 150 (100%) contained sediment and 112 (74.7%) ...