Miocene climate evolution of northern Europe: A palynological investigation from Denmark
Miocene climate evolution of northern Europe: A palynological investigation from Denmark
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DOI：
10.1016/j.palaeo.2011.05.003
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发表时间：
2011-09
期刊：
影响因子：
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通讯作者：
Linda M. Larsson;K. Dybkjær;E. Rasmussen;S. Piasecki;T. Utescher;V. Vajda
中科院分区：
文献类型：
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作者：
Linda M. Larsson;K. Dybkjær;E. Rasmussen;S. Piasecki;T. Utescher;V. Vajda
对丹麦日德兰的下-上中新世沉积物进行了孢粉学调查，对应的时间间隔约为 19 至 8 Ma。来自特别提款权的沉积物。 Vium 钻芯沉积在海洋到海洋边缘环境中，所有样本中甲藻包囊的丰度都相对较高。然而，在整个演替过程中出现了丰富多样的花粉组合，孢粉学分析表明，研究区的沿海地区在中新世期间以杉杉沼泽森林为主，这些森林也栖息着陆生被子植物，如Nyssa、Betula、Alnus和杨梅科植物。再往内陆地区，普遍存在落叶常绿混合森林。在土壤排水较好的地区或地势较高的地区，裸子植物针叶林占主导地位，其中包括松属、红杉和石杉属等类群。总体而言，研究区中新世主要地区气候属暖温带气候，年平均气温在15.5至20°C之间。通过采用共存方法结合将分类群分配到标准化气候组的方法，在与西北欧同期气候记录相关的研究演替中检测到了四种不同的中新世气候事件。最古老的事件是早期布尔迪加期期间的冷却，时间约为 19Ma，与 MBi-1 氧同位素偏移一致。大约在18.5Ma（布尔迪加利亚中期）重建了一个变暖阶段，其特征是在沉积层序中观察到的最高降水率。变暖趋势始于布尔迪加纪末期，对应于全球公认的中中新世气候最适期（MMCO），而长期的新近纪晚期降温始于塞拉瓦期中期（约 13 Ma）。
A palynological investigation has been conducted on Lower–Upper Miocene sediments from Jylland, Denmark, corresponding to the time interval of about 19 to 8Ma. The sediments, derived from the Sdr. Vium drill core, were deposited in marine to marginal-marine environments, as shown by the relatively high abundance of dinoflagellate cysts in all samples. Nevertheless, rich and diverse pollen assemblages occur throughout the succession and the palynological analysis reveals that coastal areas of the study area were during the Miocene dominated by Taxodium swamp forests that also hosted terrestrial angiosperms such as Nyssa, Betula, Alnus and elements of the Myricaceae. Further inland, a mixed deciduous–evergreen forest prevailed. In areas with better drained soils, or on elevated areas, gymnospermous conifer forests prevailed including taxa such as Pinus, Sequoia and Sciadopitys. Overall, the climate in the study area was warm temperate during major parts of the Miocene with mean annual temperatures between 15.5 and 20°C. By employing the Coexistence Approach combined with the method of allocating taxa into standardized climatic groups, four different climatic Miocene events are detected within the studied succession correlated to the coeval climate record of northwestern Europe. The oldest event is a cooling during the earlier Burdigalian, at approximately 19Ma, coinciding with the MBi-1 oxygen isotope excursion. At ca. 18.5Ma (in mid-Burdigalian) a warming phase is reconstructed, characterized by the highest precipitation rates observed in the sedimentary succession. A warming trend, starting in the latest Burdigalian, corresponds to the globally recognized Middle Miocene Climatic Optimum (MMCO) while a longer-term late Neogene cooling was initiated in the mid Serravallian, about 13Ma.