Miocene vegetation dynamics at the New Jersey Atlantic margin

该项目的总体目标是通过对花粉记录的高分辨率分析，确定和量化新泽西州浅陆架腹地在中新世气候最佳期（约~17.8 ma BP）之前、期间（约~15.7 ma BP）和之后（约~13.5 ma BP）的植被和气候变化。此外，从相同的样品中提取海洋生物形态组合（特别是鞭毛藻囊）应使用，以确定海洋领域的温度和盐度变化。这三个区间反映了中新世中期不同的气候条件：温度和大气二氧化碳值的升高、升高和快速下降。在时间分辨率为1至3 ka的情况下，应该可以识别和详细分析冷却事件（例如，mi事件）以及检测轨道诱导的周期。主要的工作假设是，新泽西州大西洋边缘腹地的植被和区域气候发展仅部分反映了中新世中期全球气候变化，而区域特性导致了中新世气候最佳反应的稀释。陆地领域的定量降水和温度数据将通过对花粉组合应用最近生活的相对方法产生，并与基于鞭毛藻囊和其他海洋代用物的海洋条件的定性估计进行比较。这种方法将允许检测陆地和海洋信号的解耦相位。结果将进一步与当地和全球构造事件以及海平面和气候变化进行比较，使用在IODP第313次探险框架内建立的稳健年龄模型。由于高沉积速率，保证了高时间分辨率和良好的地貌保存，以及构造稳定性，新泽西浅层陆架非常适合进行这种检查。

The overall goals of this project are the identification and quantification of vegetation and climate changes in the hinterland of the New Jersey shallow shelf for three intervals preceding, (around ~17.8 ma BP), during (around ~15.7 ma BP), and after the Miocene climatic optimum (around ~13.5 ma BP) via high-resolution analyses of pollen records. In addition, marine palynomorph assemblages (particularly dinoflagellate cysts) from identical samples shall be used to identify temperature and salinity changes in the marine realm. The three selected intervals reflect different climatic conditions during the middle Miocene: increasing, high, and rapidly decreasing temperatures and atmospheric carbon dioxide values. With temporal resolutions of 1 to 3 ka, the identification and detailed analysis of cooling events (e.g., Mi-events) should be possible as well as the detection of orbitally-induced cycles. The main working hypothesis is that the vegetation and regional climate development in the hinterland of the New Jersey Atlantic margin only partly reflected global climate change during the middle Miocene, and that regional peculiarities caused a diluted response to the Miocene climatic optimum. Quantitative precipitation and temperature data for the terrestrial realm will be generated via the application of the nearest-living-relative method to the pollen assemblages, and compared to qualitative estimates of marine conditions based on dinoflagellate cysts and additional marine proxies. This approach will allow detecting phases of decoupling of terrestrial and marine signals. The results will furthermore be compared with local and global tectonic events and sea level- and climate changes using the robust age models established in the framework of IODP Expedition 313. The New Jersey shallow shelf is well-suited for this kind of examination due to high sedimentation rates, guaranteeing high temporal resolution and good palynomorph preservation, and due to tectonic stability.