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

RenneEAR-9909517这个项目是对大陆洪水火山作用的起源和后果的持续研究。以前的工作证明，在这些事件中，火山活动的高峰期发生在地质上短暂的100-300万年间，但在大多数情况下，岩浆产生历史的细节并不为人所知。这项研究将提供更详细的Ar/Ar和U/Pb年代学数据，旨在改善巴拉那-埃滕代卡、中大西洋和德干圈闭省的岩浆生产历史。将详细的岩浆产生历史与改进的生物地层学时间尺度进行比较，将进一步澄清洪水火山作用和大灭绝之间的关系。此外，还将重点放在这些省份与伸展构造作用明显相关的火成岩上，如岩墙群，以更好地限制裂谷作用、岩浆作用和最终海洋盆地形成之间的关系。该项目的另一个目标是更好地描绘这些洪水火山省份的空间范围，其中一些省份在空中与其他省份重叠，只有根据年龄才能自信地区分出来。划定大西洋中部岩浆省的范围是当务之急，尽管它在北美、南美洲、非洲和欧洲广泛发生，但直到最近才被界定。

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.