The Santo Antônio Bank (SAB) is a large sand accumulation on the inner continental shelf of Salvador City, next to Todos os Santos Bay (TSB) entrance, eastern Brazilian coast. Since the sixteenth century, chroniclers report this feature as a navigational hazard. Previous studies have tried to determine the origin and volume of sands stored within this feature without success. In the present study, high-resolution shallow seismic surveys were used to investigate the architecture, origin, and evolution of the SAB. One hundred seventy kilometers of high resolution shallow seismic lines was acquired during December 2014 and February 2015 using a Meridata® sparker system operating on frequencies between 0.3 and 1.5 kHz, with a maximum 200 J of energy. Three major stratigraphic units were identified: the bedrock, a transgressive unit, and a highstand unit. The bedrock comprises sedimentary rocks of the Northern Camamu Sedimentary Basin and high-grade metamorphic rocks of the Precambrian basement. The transgressive unit is interpreted as the result of deposition in an estuarine environment infilling incised valleys. The highstand unit represents the SAB itself. A well-preserved proto-bank exists at the core of the SAB marking the early stages of bank development. This proto-bank drowned in place possibly during the 8.2-ka event. Present-day SAB and tidal prism volumes show that the bank reached a maturity phase of development. The volume of siliciclastic sands stored in the SAB is 5.98 × 10 8 m 3 . The SAB is potentially a major source of sands for beach nourishment for the urban beaches of the city of Salvador and metropolitan area, thus increasing the resilience of the city to future sea-level rises.

中文翻译：

---

Santo Antônio Bank：对位于巴西东部一个大型热带海湾入口处的偏转潮汐三角洲的高分辨率地震研究

Santo Antônio Bank (SAB) 是萨尔瓦多市内大陆架上的一个大型沙堆，毗邻巴西东部海岸的 Todos os Santos 湾 (TSB) 入口。自 16 世纪以来，编年史家将这一特征报告为航行危险。以前的研究试图确定存储在该特征中的沙子的来源和体积，但没有成功。在本研究中，高分辨率浅层地震勘测被用于研究 SAB 的结构、起源和演化。在 2014 年 12 月和 2015 年 2 月期间，使用 Meridata® 火花系统采集了 170 公里的高分辨率浅层地震线，其工作频率在 0.3 到 1.5 kHz 之间，最大能量为 200 J。确定了三个主要地层单元：基岩、海侵单元、和一个高台单元。基岩包括北卡马穆沉积盆地的沉积岩和前寒武纪基底的高级变质岩。海侵单元被解释为河口环境中的沉积结果，填充了下切的山谷。高位单位代表 SAB 本身。一个保存完好的原型银行存在于 SAB 的核心，标志着银行发展的早期阶段。这个原始银行可能在 8.2-ka 事件期间被淹没。目前的 SAB 和潮汐棱镜交易量表明，该银行已达到发展的成熟阶段。SAB 中储存的硅质碎屑砂体积为 5.98 × 10 8 m 3 。SAB 可能是萨尔瓦多市和大都市区城市海滩的海滩营养沙子的主要来源，