Early Cretaceous chalks from the North Sea giving evidence for global change
Early Cretaceous chalks from the North Sea giving evidence for global change
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DOI：
10.1038/ncomms2698
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发表时间：
2013-04
影响因子：
16.6
通讯作者：
J. Mutterlose;C. Bottini
中科院分区：
文献类型：
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作者：
J. Mutterlose;C. Bottini
在侏罗纪和白垩纪海洋中重要的初级生产者钙质纳米化石中，纳米螺是碳酸盐造岩生物。在巴雷米亚晚期和阿普tian早期（约1.26 - 1.22亿年前），纳米孔虫经历了一次危机，在海洋缺氧事件1a中达到高潮。在这里，我们展示了来自北海早巴雷米亚-早阿普提亚时代的一段纳米化石和地球化学数据，记录了在北方王国已知的最早的白垩。这些中晚期巴雷米亚白垩是在相对温暖和干旱的条件下由特有的纳米孢子开花产生的。在巴雷米亚晚期，随着养分和粘土输入的增加，纳米锥虫随之减少。在低纬度地区也发现了这种纳米锥体的下降，这与Ontong爪哇高原的就位有关。我们得出结论，在高纬度地区，在清澈和少营养的水域下，纳米锥虫也会形成岩石。它们的下降与强化温室条件下大陆径流的增加有关。
Among calcareous nannofossils, important primary producers in Jurassic and Cretaceous oceans, nannoconids were carbonate rock-forming organisms. During the late Barremian and early Aptian (~126 to 122 million years ago), nannoconids went through a crisis culminating during the Oceanic Anoxic Event 1a. Here we present nannofossil and geochemical data from a section of early Barremian–early Aptian age from the North Sea, recording the earliest chalks ever known in the Boreal Realm. These middle-late Barremian chalks were generated by blooming of endemic nannoconids under relative warm and arid conditions. A subsequent decrease of nannoconids in the latest Barremian coincides with increased nutrient and clay input. This nannoconid decline, also detected at low latitudes, was associated with the Ontong Java Plateau emplacement. We conclude that nannoconids were rock forming also at high latitudes, under clear and oligotrophic waters. Their decline was related to increased continental runoff under reinforced greenhouse conditions.