[S-IT41_28PM1] 海洋プレートの一生：誕生から解体，そして復活

[SIT41-14] ABISMOがマリアナ海溝チャレンジャー海淵で採取した堆積物コアのマフィック鉱物

*道林 克禎¹、照峰 直伸²、針金 由美子³、布浦 拓郎⁴、上原 茂樹¹、小原 泰彦⁵、宮崎 淳一⁴、高井 研⁴ (1.静岡大学理学研究科地球科学専攻、2.静岡大学理学部地球科学科、3.産業技術総合研究所地質情報研究部門、4.海洋研究開発機構、5.海上保安庁海洋情報部)

キーワード：ABISMO, Mariana Trench, Challenger Deep, sediment core, spinel, olivine

Mariana Trench is one of the deepest oceans in the world more than 10,000 m depth. Although the mantle section outcrops along the land-side slope of the southern Mariana Trench, the studied depth so far is approximately shallower than 7,000 m and therefore few geological information is available for the mantle section deeper than 7,000 m. In 2008, a sediment core has been sampled at 10,350 m in Challenger Deep of Mariana Trench by ABISMO (Automatic Bottom Inspection and Sediment Mobile) during KR08-05 cruise. The sediment core is 161.5 cm in length and contains mafic sandy grains such as olivine and spinel. In this study, we sampled the mafic minerals from the sediment core and analyzed their major element compositions. As a result, the chemical compositions of the mafic sandy grains were compatible with those of mafic minerals within the peridotites along the land-side slope of Mariana Trench shallower than 7,000 m. We will discuss the origin of these sandy grains.