Abstract The Messinian succession cropping out in a marginal basin of the Mediterranean Sea (Sinis Basin, W Sardinia) was studied in its benthic foraminiferal content in order to investigate the main palaeoenvironmental changes occurring. A shallowing upward depositional trend, from an upper bathyal-circalittoral environment to a coastal lagoon, was recognized during the pre-Messinian Salinity Crisis. In the lower part of the analyzed succession (Capo San Marco Formation), upper bathyal-circalittoral conditions are suggested by species with a wide depth-range, such as Cibicidoides pseudoungerianus, Melonis pompilioides, Oridorsalis umbonatus, bolivinids and buliminids. In the middle part of this formation, the progressively shallowing environment is indicated by the low abundance of planktonics coupled with the upward increase of shallow-water epiphytic species (Lobatula lobatula, Elphidium crispum, E. macellum, Ammonia beccarii, Hanzawaia boueana). The progressive marine restriction led to the development of hypohaline conditions typical of lagoonal environments as suggested by Ammonia tepida and oligotypic macrofaunas. The succession stops with the deposition of laminated limestones barren in fossils (Sinis Laminated Limestone Formation). A mixed siliciclastic‑carbonate platform (Torre del Sevo Formation), characterized by fluvial deposits intercalated in the marine succession, developed as suggested by benthic foraminifera, ostracods, very rare planktonic species and macrofaunas. Sinis Laminated Limestone Formation and Torre del Sevo Formation constituted part of the Terminal Carbonate Complex, strongly eroded by the Messinian Erosional Surface (MES) at its top. The palaeoecological conditions in the Sinis Basin were intermittently suitable for sustaining full-marine biota, indicating that this marginal basin was not constantly desiccated during the pre-Messinian salinity crisis.

中文翻译：

---

西尼斯盆地（西撒丁岛，地中海）前墨西拿盐度危机期间环境变化的底栖有孔虫代表

摘要 为了研究发生在地中海边缘盆地（Sinis Basin，W Sardinia）的Messinian 序列的底栖有孔虫含量，研究了发生的主要古环境变化。在前墨西拿盐度危机期间，人们认识到从上深海环流环境到沿海泻湖的逐渐变浅的向上沉积趋势。在分析序列的下部（Capo San Marco 组），深度范围较宽的物种暗示了上深海环流条件，例如 Cibicidoides pseudoungerianus、Melonis pompilioides、Oridorsalis umbonatus、bolivinids 和 buliminids。在这个阵型的中间部分，逐渐变浅的环境表现为浮游生物的丰度低，加上浅水附生物种（Lobatula lobatula、Elphidium粑粑、E. macellum、Ammonia beccarii、Hanzawaia boueana）的向上增加。正如 Ammonia tepida 和寡型大型动物群所暗示的那样，渐进的海洋限制导致了泻湖环境典型的低盐条件的发展。随着化石中贫瘠​​的层状石灰岩的沉积（Sinis 层状石灰岩组），演替停止。混合硅质碎屑-碳酸盐平台（Torre del Sevo 地层），其特征是河流沉积物插入海洋演替中，按照底栖有孔虫、介形动物、非常稀有的浮游生物和大型动物群的建议发育。Sinis 层状石灰岩地层和 Torre del Sevo 地层构成终端碳酸盐岩复合体的一部分，被其顶部的墨西拿侵蚀面 (MES) 强烈侵蚀。Sinis 盆地的古生态条件间歇性地适合维持完整的海洋生物群，这表明该边缘盆地在前墨西拿盐度危机期间并未持续干燥。