Modern cemented intervals (beachrock, firmgrounds to hardgrounds and concretionary layers) form in the lagoon and intertidal sabkha of Abu Dhabi. Seafloor lithification actively occurs in open, current-swept channels in lowlying areas between ooid shoals, in the intertidal zone of the middle lagoon, some centimetres beneath the inner lagoonal seafloor (i.e. within the sediment column) and at the sediment surface the intertidal sabkha. The concept of ‘concretionary sub-hardgrounds’, i.e. laminar cementation of sediments formed within the sediment column beneath the shallow redox boundary, is introduced and discussed. Based on calibrated radiocarbon ages, seafloor lithification commenced during the Middle to Late Holocene (ca 9000 cal yr BP), and proceeds to the present-day. Lithification occurs in the context of the actualistic relative sea-level rise shifting the coastline landward across the extremely low-angle carbonate ramp. The cemented intervals are interpreted as parasequence boundaries in the sense of ‘marine flooding surfaces’, but in most cases the sedimentary cover overlying the transgressive surface has not yet been deposited. Aragonite, (micritic) calcite and, less commonly, gypsum cements lithify the firmground/hardground intervals. Cements are described and placed into context with their depositional and marine diagenetic environments and characterized by means of scanning electron microscope petrography, cathodoluminescence microscopy and Raman spectroscopy. The morphology of aragonitic cements changes from needleshaped forms in lithified decapod burrows of the outer lagoon ooidal shoals to complex columnar, lath and platy crystals in the inner lagoon. Precipitation experiments provide first tentative evidence for the parameters that induce changes in aragonite cement morphology. Data shown here shed light on ancient, formerly aragonite-cemented seafloors, now altered to diagenetic calcites, but also document the complexity of highly dynamic near coastal depositional environments.

中文翻译：

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阿布扎比泻湖和潮间带沙布哈的全新世晚期至最近的文石胶结海侵滞后沉积物

在阿布扎比的泻湖和潮间带沙布哈形成现代胶结层段（海滩岩、硬地到硬地和胶结层）。海底石化在鲕形浅滩之间的低洼地区、中泻湖的潮间带、内泻湖海底（即在沉积柱内）下方几厘米处以及在沉积物表面的潮间带浅滩中活跃地发生​​在开放的、洋流冲刷的通道中。介绍并讨论了“胶结次硬质地层”的概念，即浅层氧化还原边界下方沉积柱内形成的沉积物的层状胶结作用。根据校准的放射性碳年龄，海底岩石化开始于全新世中晚期（大约 9000 cal yr BP），并持续到今天。岩化发生在实际相对海平面上升将海岸线向陆上移动穿过极低角度碳酸盐斜坡的背景下。胶结层段被解释为“海侵表面”意义上的准层序边界，但在大多数情况下，覆盖在海侵表面上的沉积盖层尚未沉积。文石、（泥晶）方解石和不太常见的石膏水泥使硬地/硬地层段石化。水泥被描述并置于其沉积和海洋成岩环境中，并通过扫描电子显微镜岩相学、阴极发光显微镜和拉曼光谱进行表征。文石胶结物的形态从外泻湖卵形浅滩的石化十足目洞穴中的针状形式转变为内泻湖中复杂的柱状、板条状和板状晶体。沉淀实验为引起文石胶结物形态变化的参数提供了初步证据。这里显示的数据揭示了古老的、以前是文石胶结的海底，现在变成了成岩方解石，但也记录了近海岸沉积环境的高度动态的复杂性。