Organic matter preservation in sediments of the Peru and Oman continental margin@en

Detailed petrographical and bulk geochemical investigations of organic matter (OM) have been performed on sediments deposited below or close to upwelling areas offshore Peru (ODP-Leg 112; Sites 679, 681, 688) and Oman (ODP-Leg 117; Sites 720, 723, 724) in order to obtain a quantitative understanding of its accumulation and degradation. Microscopical as well as nanoscopical investigations reveal that the OM in sediments affected by upwelling mechanisms mainly (up to 98%) consists of unstructured (amorphous) organic aggregates without any apparent biological structures. In sediments which are not or to a lesser extent affected by upwelling (Site 720) terrestrial OM predominates. […]针对秘鲁近海（大洋钻探计划ODP第112航次：站位679、681、688）与阿曼近海（ODP第117航次：站位720、723、724）上升流区下方或邻近区域的沉积物，本研究开展了有机质（organic matter, OM）的详细岩石学与全量地球化学调查，以定量解析其堆积与降解过程。显微及纳米级观测表明，受上升流作用影响的沉积物中，有机质主要（占比最高可达98%）由无明显生物结构的无结构（无定形）有机聚集体构成。而在未受或仅轻微受上升流作用影响的沉积物（如站位720）中，陆源有机质占据主导地位。[…]