Abstract Dinoflagellate cysts and acritarchs are excellent proxies for biostratigraphic and paleoceanographic studies in neritic sequences. However, Neogene marine palynological studies in tropical latitudes are scarce. Here, we analyzed the marine palynological contents (dinoflagellate cysts, acritarchs, foraminiferal test linings and prasinophytes) of 40 samples from a well drilled in northernmost Colombia, southern Caribbean Sea, spanning the late Chattian–late Burgidalian time interval (~24.1–17.3 Ma). We propose a biostratigraphic scheme that includes an upper Chattian–lower Aquitanian Minisphaeridium latirictum Interval Zone (~23.9–22.0 Ma), an upper Aquitanian Achomosphaera alcicornu Interval Zone (~22.0–20.3 Ma), and a Burdigalian Cribroperidinium tenuitabulatum Interval Zone (~20.3–17.5 Ma). Our results reveal several biostratigraphic events that are heterochronous compared to high latitudes. Furthermore, the conspicuous shift from a peridinioid-dominated to a gonyaulacoid-dominated dinoflagellate cyst assemblage towards the Aquitanian–Burdigalian boundary (~20.7 Ma) indicates a reduction in marine primary productivity. This paleoproductivity decline was probably driven by the initial constriction of the Central American Seaway.

中文翻译：

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哥伦比亚加勒比边缘的早中新世海洋孢粉学：生物地层学和古海洋学意义

摘要 甲藻囊肿和 acritarchs 是浅海层序中生物地层学和古海洋学研究的极好代表。然而，热带纬度的新近纪海洋孢粉学研究很少。在这里，我们分析了 40 个样本的海洋孢粉内容物（甲藻包囊、acritarchs、有孔虫测试衬里和 prasinophytes），这些样本来自在哥伦比亚最北端、加勒比海南部钻井的 40 个样本，跨越了 Chattian 晚期-Burgidalian 晚期时间间隔（~24.1-17.3 Ma ）。我们提出了一个生物地层方案，包括一个上查特-下 Aquitanian Minisphaeridium latirictum 间隔带（~23.9-22.0 Ma）、一个上 Aquitanian Achomosphaera alcicornu 间隔带（~22.0-20.3 Ma）和一个 Burdigalian Cribroperidinium tenuitabulatum 带（~23.9-22.0 Ma）。 –17.5 毫安）。我们的结果揭示了几个与高纬度地区相比是异时的生物地层事件。此外，朝向 Aquitanian-Burdigalian 边界（~20.7 Ma）从 peridinioid 主导到 gonyaulacoid 主导的甲藻囊肿组合的显着转变表明海洋初级生产力下降。这种古生产力下降可能是由中美洲海道的最初收缩造成的。