Formation and paleoclimatic interpretation of a continuously laminated Sapropel S5: A window to the climate variability during the Eemian interglacial extreme in the Eastern Mediterranean

腐泥层广泛分布在东地中海盆地，并已在过去的气候变化在高纬度和低纬度气候之间的界面，以及生物生产，底层水缺氧，并加强有机质保存之间的相互作用进行了大量的研究。知识腐泥形成过程中的机制和环境，从层压部分，提供定量估计的生产力和最高的时间分辨率对这些过程中，仍然是有限的不完整的，只有部分层压间隔的数量很少。在这里，我们建议研究一套完整的，丰富的，连续层压（纹）部分腐泥S5的Eemian期（约119-124 kyr BP）。对树脂浸渍和冰冻切片的连续X射线荧光扫描、电子显微镜成像（二次和反向散射电子）和地球化学微量分析（能量分散X射线分析）技术将用于确定单个纹层的组成，并量化其每年至百年时间尺度的间距和频率。本研究将提供有关薄层形成，生产力变化的性质和规模，以及可能的周期和事件的年表影响S5沉积在极端温暖的Eemian期间的详细信息。这些结果也将有助于限制形成的黑色页岩在地质过去的海洋缺氧事件（OAE），在那里记录的成岩过程的影响。此外，我们将能够测试的硅藻垫形成的模型作为一个重要的“功能类型”的生物泵硅出口和C下降的角度在地中海连续层压硅藻腐泥。

Sapropelic layers are widespread in the Eastern Mediterranean Basin and have been subject to numerous studies on past climatic variability at the interface between high- and low-latitude climates, and on the interplay between biological production, bottom-water anoxia, and enhanced organic matter preservation. Knowledge on mechanisms and environment during the sapropel formation from laminated sections, providing quantitative estimates of productivity and highest temporal resolution on these processes, is still limited by the small number of incomplete, only partially laminated intervals available. Here, we propose to study a suite of complete, diatom-rich, continuously laminated (varved) sections of sapropel S5 of the Eemian period (~119-124 kyr BP). Continuous XRF-scanning, electron microscopic imagery (secondary and backscatter electron) and geochemical microanalysis (energy-dispersive X-ray analysis) techniques on resin-impregnated and frozen sections will be used to identify the composition of individual laminae and to quantify their spacing and frequency on annual to centennial timescales. The present study will provide detailed information on the lamina formation, on the nature and the scales of productivity variability, and on the chronology of possible cycles and events affecting the S5 deposition during the extreme warmth of the Eemian period. These results will also help to constrain the formation of black-shales in the geological past during oceanic anoxic events (OAEs), where records are affected by diagenetic processes. Further, we will be able to test the model of diatom mat formation as an important “functional type” of the biological pump for Si export and C drawdown from the perspective of continuous laminated diatomaceous sapropels in the Mediterranean.