Late Cretaceous climatic change in a mid latitude setting (Mississippi, USA): a multiproxy palaeoenvironmental study

晚白垩世的气候研究往往集中在相对快速变化的短时间间隔，例如海洋缺氧事件2和马斯特里赫特气候振荡。因此，人们对这种变化的长期背景知之甚少。我提议的研究的目的是记录整个坎帕尼亚-马斯特里赫特时期的气候变化，并确定导致马斯特里赫特时期气候不稳定的长期变化。我将使用保存完好的岩心（密西西比埃文斯舒夸拉克岩心）的材料来研究这一点，该岩心提供了完整的中纬度陆架沉积记录。TEX 86的高分辨率测量（作为地表水古温度的替代物）将成为解释坎帕尼亚-马斯特里赫特气候的基础。应测量大块岩石稳定同位素（δ 13 C、δ 18 O）以及单一种类颗石方解石的稳定同位素和Sr/Ca比值，以了解其他环境参数（例如，碳循环、透光层营养负荷）。关键钙质超微化石分类群的绝对计数和形态测量将提供进一步的古生态学和古海洋学数据，这些数据将与地球化学数据集相结合。我的研究的所有结果，然后将进行比较，浮游生物和底栖有孔虫的数据，提供一个真正的多代理在此期间的主要水柱条件的评价。

Late Cretaceous climate studies tend to focus on short intervals of relatively rapid change, e.g. the Oceanic Anoxic Event 2, and the Maastrichtian climate oscillations. Consequently, the long-term context of such change is poorly understood. The objective of my proposed study is to record climate change through the entire Campanian-Maastrichtian, and to determine the longer-term changes that led up to climatic instability in the Maastrichtian. I will investigate this by using well-preserved material from a corehole (Evans Shuqualak core, Mississippi) that provides a complete shelfal, mid-latitude sedimentary record. High-resolution measurements of TEX86 (as a proxy for surface-water palaeo-temperature) shall form the backbone to the interpretations of the Campanian–Maastrichtian climate. Bulk rock stable isotopes (δ13C, δ18O) as well as stable isotopes and Sr/Ca-ratios from single species coccolith calcite, shall be measured to provide an insight into other environmental parameters (e.g. C-cycling, photic zone nutrient load). Abundance counts and morphometric measurements of key cal-careous nannofossil taxa will supply further palaeoecological and palaeoceanographical data, which will be integrated with the geochemical data sets. All findings of my study will then be compared to planktonic and benthic foraminiferal data, to provide a truly multiproxy evaluation of the prevailing water-column conditions during this interval.