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

自1990年以来，人们提出了几种类似的全球气候和海洋变化模型，以解释志留纪地层中记录的岩性、海平面变化、生物和地球化学事件。第一个也是最著名的模型是杰普森的模型，他将志留纪划分为一系列被短暂的海洋事件分隔开的海洋状态，在这些事件中发生了戏剧性的变化，包括与初级生产力下降有关的动物群灭绝。几乎所有的模型的详细文件都来自波罗的海地区。测试这些模型需要额外的志留纪事件进行检查。该团队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，其中没有重大的“事件”记录。这些数据将来自部分，跨越3000公里的南部劳伦蒂亚，这是位于远离波罗的海在志留纪。研究将产生一个重建的沉积，生物和地球化学的历史，为间隔约5.0米的南部克拉通劳伦蒂亚和延伸到盆地近阿巴拉契亚造山带。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，这些水循环从南极边缘附近穿过陆表海，进入与全球海洋或多或少相连并与构造事件相互作用的盆地。这将包括志留纪海洋变化的区域表达的第一次分析，并将提供深入比较与波罗的海相关的部分所需的详细文件。这将有助于更好地理解志留纪以及古生代气候和海洋变化的地层记录的性质。数据将被重新储存，包括用于额外分析的未处理样品（几丁虫、孢粉、锶同位素等），和信息，以便纳入一个动态的、互动的和按时间校准的网络，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.