In this investigation, we carried out a Mid-Holocene paleoenvironmental reconstruction based on fossilized benthic foraminifera, retrieved from sedimentary deposits located in Bahía Samborombón coastal plain. A total of 38 species, grouped into 19 genera, were identified. The assemblage, constituted mainly by Buccella peruviana (d’Orbigny), Cribroelphidium poeyanum (d’Orbigny), Ammonia parkinsoniana (d’Orbigny) and Ammonia tepida (Cushman), indicate predominantly abnormal marine conditions, characterized by low oxygen levels between ca. 6880–6640 and 5600–5430 yrs cal. BP. During this interval, a quantitative analysis carried out on the assemblages as well as indexes suggest found three different paleoenvironments. The first one, occurring ca. 6880–6640 yrs cal. BP, was a brackish environment with low oxygenation levels and low bottom energy. Then, ca. 6500–6250 yrs cal. BP, an environment with more marine influence, increased oxygen levels and higher energy prevailed. This higher oxygenation could be related to the flow of seawater into the area during the Mid-Holocene sea-level highstand. The third paleoenvironment developed ca. 5590–5430 yrs cal. BP, was under a gradual transition back to a brackish environment with low oxygen levels as well as low energy.

中文翻译：

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中全新世海平面高位期间布宜诺斯艾利斯省（阿根廷）东北沿海平原的有孔虫古生物多样性和古环境

在这项调查中，我们基于从位于 Bahía Samborombón 沿海平原的沉积沉积物中提取的底栖有孔虫化石进行了中全新世古环境重建。共鉴定出38种，分为19属。该组合主要由 Buccella peruviana (d'Orbigny)、Cribroelphidium poeeanum (d'Orbigny)、Ammonia parkinsoniana (d'Orbigny) 和 Ammonia tepida (Cushman) 组成，表明海洋条件主要异常，其特征是约 6880-6640 和 5600-5430 年校准。BP。在此期间，对组合进行的定量分析以及指数表明发现了三种不同的古环境。第一个，大约发生。6880–6640 年 cal。BP 是一种含氧量低且底部能量低的微咸环境。然后，约 6500–6250 年 cal。BP 是一个受海洋影响更大的环境，氧气含量增加，能量更高。这种较高的氧化可能与全新世中期海平面高位期间海水流入该地区有关。第三古环境发展约。5590–5430 年 cal。BP 正在逐渐过渡到低氧和低能量的微咸环境。