COLLABORATIVE RESEARCH: Ordovician and Silurian Explosive Volcanism in the Iapetus Region: Tectonomagmatic, Tectonic,Event-Stratigraphic, and Biologic Implications

该项目继续研究奥陶纪和志留纪的K- 在Iapetus地区的Ekononites，开始于1990年。 的 北美米尔布里格钾膨润土代表了 与Baltoscandia的“大膨润土”相同的火山灰落下， 可以使用这张床作为一个独特的时间平面为各种 区域地质研究，比如最近开始的博士学位， 中奥陶世牙形刺生物相分异研究 土卫八地区及其生态控制。 显然， 已知最大的火山灰瀑布，米尔布里格-“大膨润土” 提供了一个不寻常的机会来研究死亡和灭绝 一个巨大的火山灰降落对海洋生物群的影响，这样的研究将 进行。 此外，这个层位，沿着新的生物地层 数据，将用于甜的美国图形应用程序 因此，与欧洲继承的相关性方案极大地 提高了跨大西洋相关性的精确度。 地球动力学和事件地层学研究将包括化学 指纹的选择床和建模的米尔布里格-“大 基于区域粒度分析的膨润土喷发。 这些数据也将用于获得 中奥陶世土卫八的宽度。 我们还计划让 生物地层控制良好高精度U-Pb测年 钾镁矾，将提供重大贡献， 奥陶纪-志留纪时间尺度

The project continues of study of Ordovician and Silurian K- bentonites in the Iapetus region that was started in 1990. The discovery that the Millbrig K-bentonite in North America represents the same ash fall as the "Big Bentonite" in Baltoscandia makes its possible to use this bed as a unique time plane for various regional geological studies, such as a recently started Ph.D., project on Middle Ordovician conodont biofacies differentiation in the Iapetus region and its ecologic controls. Being apparently the largest volcanic ash fall known, the Millbrig- "Big-Bentonite" offers an unusual opportunity to study mortality and extinction effects of a giant ash fall on marine biota, and such a study will be undertaken. Also, this horizon, along with new biostratigraphic data, will be used for application of Sweet's American graphic correlation scheme to European successions thereby greatly increasing the precision in trans-Atlantic correlations. Geodynamic and event-stratigraphic studies will include chemical fingerprinting of selected beds and modeling of the Millbrig- "Big Bentonite" eruption based on regional grain-size pattern analyses. These will also be used for obtaining a distance figure of the width of the Iapetus in the Middle Ordovician. We also plan to get high-precision U-Pb dates on biostratigraphically well-controlled K-bentonites that will provide significant contributions to the Ordovician-Silurian time scale.