At wave-dominated coasts it is common to find coastal barriers that might be in a progradational pattern and can compose sedimentary capes. Those prograding coastal barriers can be characterized by beach ridges or barrier spits, or even by a more complex pattern depending on the processes controlling their formation. In this study geomorphological mapping, topographic surveys, ground-penetrating radar profiles and optically stimulated luminescence (OSL) dating were performed on the coastal barrier systems of São Tomé cape (north of Rio de Janeiro state, Brazil). The aim was to reconstruct its spatial and temporal evolution and, by this, better understand the interplay between sedimentary cape formation and its driving mechanisms as well as their function as potential archives for long-term environmental dynamics. The study site is characterized by lagoonal and fluvio-lagoonal depressions, and a lagoon surrounded by beach ridges that are interleaved with barrier spits and erosional truncations. Both types of coastal barriers reach up to 6 m above sea-level. Shallow geophysical analysis identified seven radar facies that characterize the stratigraphy of the targeted morphologies. Beach ridges are mainly composed by planar, seaward dipping, subparallel, continuous reflectors which represents their progradation, while barrier spits have planar to convex up, parallel, landward migrating reflectors. Geochronological results demonstrate that the coastal barriers were formed during the Late Holocene. Beach ridge formation until ∼2700 years ago was interrupted by the formation of a barrier spit system between ∼2300 and ∼2000 years ago. This barrier spit system was responsible for the formation of an enclosed lagoon, the Salgada lagoon, and was truncated by a set of beach ridges formed since ∼2000 years ago and continuing to the present shoreline. The different types of coastal barriers indicate a change in hydrodynamic processes during the Late Holocene, with an alternation between the predominance of wave-induced cross-shore transport, responsible for the formation of beach ridges and the predominance of longshore transport, responsible for the formation of barrier spits. Besides that, erosional truncations and unconformities indicate the interruption of shoreline progradation and the impact of erosion due to the storms. This illustrates the complex and highly dynamic development of São Tomé Cape with wave climate and storms as its most important drivers. More generally, this study shows that sedimentary capes may be regarded as geoarchives with potential for the reconstruction of coastal processes over Holocene timescales.

在以波浪为主的海岸上，通常会发现沿海栅栏可能呈渐进型并可能构成沉积角。那些不断发展的沿海壁垒的特征可能在于滩脊或壁垒喷口，甚至取决于控制其形成过程的更复杂的模式。在这项研究中，对圣多美海角（巴西里约热内卢州北部）的海岸屏障系统进行了地貌制图，地形勘测，探地雷达轮廓和光学激发发光（OSL）测年。目的是重建其时空演化，从而更好地了解沉积披风形成及其驱动机制之间的相互作用，以及它们作为长期环境动力学的潜在档案的功能。研究地点的特征是泻湖和河水泻湖洼地，泻湖周围环绕着海滩山脊，这些山脊与障碍物喷口和侵蚀性截断物交织在一起。两种类型的沿海屏障都可以达到海平面以上6 m的高度。浅层地球物理分析确定了七个雷达相，这些相表征了目标形态的地层学特征。滩脊主要由平面的，向海浸入的，次平行的，连续的反射器组成，这些反射器代表着它们的渐进性；而阻挡物喷口则具有从平面到凸出的，平行的，向内的迁移反射器。地质年代学结果表明，沿海壁垒是在全新世晚期形成的。直到2700年前的海滩山脊形成都被2300到2000年前之间的屏障吐水系统的形成打断了。这种屏障吐水系统负责形成一个封闭的泻湖，即萨尔加达泻湖，并被大约2000年前形成的一组海滩山脊所截断，一直延伸到目前的海岸线。不同类型的海岸屏障表明，晚全新世时期的水动力过程发生了变化，其中波浪引起的跨岸运输的主要优势（构成海滩脊的形成）和远岸运输的主要优势（形成的原因）之间发生了交替。屏障吐痰。除此之外，侵蚀的截断和不整合还表明海岸线恶化的中断以及暴风雨对侵蚀的影响。这说明了波多黎各海浪的复杂和高度动态发展，其中波涛气候和风暴是其最重要的驱动力。更普遍，