Laminae type and possible mechanisms for the formation of laminated sediments in the Shaban Deep, northern Red Sea

[摘要] Laminated sediments in the Shaban Deep, a brine-filled basin in the northernRed Sea, were analyzed with backscattered electron imagery. Here we presentpossible mechanisms involved in the formation of laminae of various typesand homogenous intervals arising from the detailed investigation ofmulticore GeoB 7805-1 (26°13.9' N and 35°22.6' E; water depth 1447 m)and gravity core GeoB 5836-2 (26°12.61' N, 35°21.56' E; water depth1475 m). Sediment makeup includes six types: a) a laminated structure withalternating light (mainly coccoliths) and dark (diatom frustules) layers,where the diatom component is indicative of the intra-annual variabilitybetween stratification and mixing events; b) a pocket-like structureattributed to the sinking of particles within fecal pellets and aggregates;c) a matrix of tightly packed diatoms that relates to extendedstratification/mixing periods of the water column; d) homogenous intervalsthat result from turbidity deposition; e) silt accumulations which originmay lie in agglutinated foraminifers; and f) pyrite layers with pyriteformation initiated at the seawater-brine interface.

[学科分类] 海洋学与技术