Continued Geochronologic, Paleomagnetic, and Rock-Magnetic Studies of the Parana-Etendeka Flood Volcanic Province

9628065雷恩拟议的研究将为澄清非洲西南部和南美洲东部巴拉那-埃滕代卡省(PEP)洪水火山活动的时空演变提供基本数据。PEP是已知的最大的大陆洪水火山省份之一，这里获得的数据将与洪水火山活动起源的更广泛问题相关。将结合正在进行的地层学和岩石学研究，通过高精度的地质年代学、古地磁和岩石磁学工作来阐明火山作用、特里斯坦-达库尼亚热点和南大西洋白垩纪早期裂谷之间的关系。将为纳米比亚埃滕代卡省和乌拉圭巴拉那省的火山岩段建立新的详细的磁性地层学。在135-120 Ma的时间间隔内，将得到南美洲和南部非洲的精确和准确的视极地漂移路径(APWP‘s)；APWP’s将量化南大西洋不对称开放的旋转，并将用于精炼特里斯坦热点的踪迹。40Ar/39Ar和U/Pb测年将被用来更确定地约束火山活动中的任何迁移趋势。将从古地磁和岩石磁学上检验横跨大西洋的各个水流之间的相关性；这种相关性的推论将成为冈瓦瓦兰岛西部漂移前重建的高精度基础。将尝试使用来自广泛分离的流动序列的磁化率各向异性(AMS)来确定火山流动方向(限制来源的位置)，特别是正在测试跨大西洋对比的单元。

9628065 Renne The proposed research will provide fundamental data toward clarifying the spatial-temporal evolution of flood volcanism in the Parana-Etendeka province (PEP) of southwestern Africa and eastern South America. The PEP is one of the largest continental flood volcanic provinces known, and data acquired herein will be relevant to broader questions about the origin of flood volcanism. Relations between volcanism, the Tristan da Cunha hotspot, and Early Cretaceous rifting of the South Atlantic will be elucidated by high-precision geochronologic and paleomagnetic and rock magnetic work that will be done in connection with ongoing stratigraphic and petrologic studies. New and detailed magnetostratigraphy will be established for volcanic sections in the Etendeka Province of Namibia as well as the Parana Province of Uruguay. Refined and well-dated apparent polar wander paths (APWP's) will be derived for both South America and southern Africa over the interval of 135-120 Ma; the APWP's will quantify rotation due to asymmetric opening of the South Atlantic and will be used to refine the trace of the Tristan hotspot. 40Ar/39Ar and U/Pb dating will be used to constrain with greater certainty any migratory trends in volcanism. Correlations between individual flows across the Atlantic will be tested paleomagnetically and rock-magnetically; a corollary of such correlation will be a high-precision basis for pre-drift reconstruction of western Gondwanaland. Determination of volcanic flow directions (constraining locations of sources) will be attempted using anisotropy of magnetic susceptibility (AMS) from widely separated flow sequences, particularly units being tested for Transatlantic correlation.