This study aims to improve the knowledge on the geological evolution of the Maricá Lagoon (Rio de Janeiro) during the Holocene. One hundred and three samples from four boreholes and GPR data were acquired. Laboratory analyses included grain size and morphology, color, organic matter contents, fossils, mineral composition, and ¹⁴C dating. The results indicate that the 12.5 m thick sedimentary section studied here represents the last 8111 years of lagoonal deposition. Five sedimentary facies were identified: (1) subrounded sand facies (containing a gravel subfacies) which occur along the southern margin; (2) silty sand facies occurring at the transition from the margin to the lagoon center; (3) sandy silt facies and (4) silt/clayey silt facies which cover the calmer, central areas of the lagoon; and (5) angular sand facies which occur only at the surface of the northern margin. The organic matter content in the mud varied from 18% to 81%. Sedimentation rates up to 4277 cal years BP in the western margin were 0.27 cm/y and 0.15 cm/y in the deeper, central lagoon areas, and 0.20 cm/y since then. The sedimentary facies and organisms (molluscs and sponges) indicated that the Maricá Lagoon has changed little during the Holocene. At about 8111 cal years BP, the lagoon was an important freshwater basin with occasional saltwater influence. At about 5600–5000 years ago, during the maximum Holocene transgression, the lagoon attained its maximum dimensions and prevailing marine influences. Overwash processes and inlets enabled the formation of washover fans and flood-tidal delta deposits that have been recognized since the early formation stages of the Pleistocene barrier. From 4645 cal years BP to the present day, the connection between the lagoon and the sea has occurred sporadically at the southeast extreme of the lagoon (Barra Lagoon). Today's sedimentary dynamics are influenced by fluvial input (which is building up a lagoonal delta) and by winds, which transport sands from the barrier into the lagoon, in addition to generating waves capable of remobilizing the marginal and bottom lagoon sediments.

本研究旨在提高对全新世马里卡泻湖（里约热内卢）地质演化的认识。获得了来自四个钻孔的 103 个样本和 GPR 数据。实验室分析包括粒度和形态、颜色、有机质含量、化石、矿物成分和¹⁴C 约会。结果表明，这里研究的 12.5 m 厚的沉积剖面代表了过去 8111 年的泻湖沉积。确定了五种沉积相：（1）沿南缘出现的亚圆形砂相（含砾石亚相）；(2) 发生在边缘向泻湖中心过渡的粉砂相；(3) 砂质粉砂相和 (4) 粉砂/粘土质粉砂相，覆盖泻湖较平静的中心区域；(5) 角砂相仅出现在北缘表面。泥浆中的有机物含量从 18% 到 81% 不等。西部边缘高达 4277 卡年 BP 的沉积率在较深的中央泻湖区域为 0.27 厘米/年和 0.15 厘米/年，此后为 0.20 厘米/年。沉积相和生物（软体动物和海绵）表明 Maricá Lagoon 在全新世期间变化不大。在大约 8111 卡年 BP 时，泻湖是一个重要的淡水盆地，偶尔会受到咸水的影响。在大约 5600-5000 年前，在全新世最大海侵期间，泻湖达到其最大尺寸和主要海洋影响。自更新世屏障的早期形成阶段以来，冲刷过程和入口形成了冲刷扇和洪水-潮汐三角洲沉积物。从 4645 卡年 BP 到今天，泻湖和海洋之间的连接偶尔发生在泻湖的东南端（巴拉泻湖）。今天'