Collaborative Research: Late Wenlock-Ludlow (Silurian) Oceanic Episodes and Events, Southern Laurentia

自1990年以来，已经提出了几个类似的全球气候和海洋变化模型来解释志留纪地层记录的岩性、海平面上升、生物和地球化学事件。第一个，也是最突出的一个模型是Jeppsson的模型，他将志留纪细分为一系列海洋状态，这些海洋状态由短暂的海洋事件分开，在这些事件中发生了剧烈的变化，包括与初级生产力下降有关的动物灭绝。几乎所有模型的详细文件都来自波罗的海地区。要检验这些模型，还需要考察其他志留纪事件。该小组将研究志留纪的时间跨度，其中包括两个主要事件（Mulde和Lau），一个次要事件（Linde）和一系列海洋事件之间的变化，这些事件没有记录到重大的“事件”。这些数据将来自横跨劳伦西亚南部3000公里的部分，该地区在志留纪时期远离波罗的海。该研究将重建大约5.0万年的沉积、生物和地球化学历史，这段时间横跨劳伦西亚南部克拉通，并延伸到阿巴拉契亚造山带附近的盆地。这将有助于评估与水循环有关的生物和地球化学因素的地理趋势，这些水循环从靠近克拉通边缘的地方穿过一个表海，进入与全球海洋或多或少有良好联系的盆地，并与构造事件相互作用。这将包括对志留纪海洋变化的区域表现的第一次分析，并将提供与波罗的海有关部分进行深入比较所需的详细文件。对志留纪的气候和海洋变化的地层记录的性质，从而对古生代的气候和海洋变化的性质，将有更好的了解。数据将重新存储，包括用于进一步分析的未处理样本（几丁虫、异形、sr同位素等），并提供信息，以便纳入动态、互动和时间校准的网络，例如CHRONOS项目。

Several similar models of global climate and oceanic change have been proposed since 1990 to explain lithologic, eustatic, biotic and geochemical events recorded from Silurian strata. The first, and still most prominent, of the models is that of Jeppsson, who subdivided the Silurian into a series of oceanic states separated by short-lived oceanic events, during which dramatic changes, including faunal extinctions related to drops in primary productivity, occurred. Nearly all of the detailed documentation of the models comes from the Baltic region.Testing these models requires that additional Silurian events be examined. The team will examine a span of Silurian time that includes two major events (Mulde and Lau), a minor event (Linde) and a series of shifts between oceanic episodes for which no significant 'events' have been recorded. The data will come from sections that span 3000 km across southern Laurentia, which was located distant from Baltica during the Silurian.The research will yield a reconstruction of the depositional, biotic, and geochemical history for an interval of approximately 5.0 my across the southern craton of Laurentia and extending into basins proximal to the Appalachian orogenic area. This will allow for evaluation of geographic trends in biological and geochemical factors related to water circulation from near the cratonic margin across an epeiric sea and into basins that were more or less well connected to the global ocean and were interacting with tectonic events. This will comprise the first analysis of regional expression of Silurian oceanic changes, and will also provide the detailed documentation required for in-depth comparison to sections associated with Baltica. A far better understanding of the nature of the stratigraphic record of climatic and oceanic change for the Silurian, and thereby also the Paleozoic, will result. Data will be reposited, including unprocessed samples for additional analyses (chitinozoan, palynomorphs, Sr-isotopes, etc.), and information made available for inclusion in a dynamic, interactive and time-calibrated network, such as the CHRONOS project.