ABR: Continued Geochronologic, Paleomagnetic, and Rock-Magnetic Studies of Continental Flood Volcanism

这个项目是正在进行的关于大陆洪水火山作用的起源和后果的研究的继续。先前的研究已经证明，在这些事件中，火山活动的高峰在地质上的短暂间隔为1- 300万年，但在大多数情况下，岩浆产生历史的细节并不为人所知。该研究将提供更详细的Ar/Ar和U/Pb年代学数据，旨在改善Parana-Etendeka、大西洋中部和德干圈闭省的岩浆生产历史。详细的岩浆生产历史和改进的生物地层时间尺度的比较将进一步阐明洪水火山作用与大灭绝之间的关系。额外的重点将放在这些省份的火成岩测年上，这些火成岩明显与伸展构造活动有关，比如岩脉群，以便更好地约束裂谷作用、岩浆作用和海洋盆地最终形成之间的关系。该项目的另一个目标是更好地描绘这些洪水火山省的空间范围，其中一些省在空中与其他省重叠，只能根据年龄进行区分。划定中大西洋岩浆省的范围是当务之急，尽管中大西洋岩浆省在南北美洲、非洲和欧洲广泛存在，但直到最近才被定义。

RenneEAR-9909517This project is a continuation of ongoing research into the origins and consequences of continental flood volcanism. Previous work has documented that the peak of volcanic activity during these events occurs over geologically brief intervals of 1-3 million years, but the details of magma production history are not well known in most cases. This study will provide more detailed Ar/Ar and U/Pb geochronologic data aimed at improved magma production histories in the Parana-Etendeka, Central Atlantic, and Deccan Traps provinces. Comparison between detailed magma production histories and improved biostratigraphic time-scales will further clarify the relations between flood volcanism and mass extinctions. Additional emphasis will be placed on dating igneous rocks in these provinces that are clearly associated with extensional tectonism, such as dikes swarms, to better constrain the relationship between rifting, magmatism, and the eventual formation of ocean basins. A further goal of the project is to better delineate the spatial extent of these flood volcanic provinces, some of which overlap aerially with others and can be confidently distinguished only on the basis of age. Delineating the extent of the Central AtlanticMagmatic Province, only recently defined despite its widespread occurrence in North and South America, Africa, and Europe, is a top priority.