Field and laboratory investigations into remagnetizations and remanence acquisition

沉积盆地的古地磁和岩石地磁研究已被证明是关于矿床起源、反转时间尺度的发展和过去气候变化等各种主题的重要信息来源。因此，了解地质和环境过程在盆地内产生、改变和破坏特定磁化成分的重要性再怎么强调也不过分。申请人之前的古地磁和岩石地磁研究主要集中在北美中部威利斯顿盆地的奥陶系-密西西比系碳酸盐岩上。这些碳酸盐提供了重要的信息；然而，它们通常具有弱的自然磁化，并带有一个或多个次级磁化，这些次级磁化可能与特定的成岩事件有关，也可能与之无关。更复杂的是，如果次级磁化不能被识别，我们对盆地中发生的过程的理解可能会受到影响。提出的研究旨在减少和限制这些复杂性，即使他们继续检查沉积岩中再磁化起源的传统假设，研究剩余物获取机制，并评估一些可能的再磁化因素。为实现长期目标，提出了三种新的方法：过去对威利斯顿和加拿大西部沉积盆地的古地磁研究将扩展到更年轻的碎屑岩（白垩纪维京组及等效地层），将进行流体/温度相互作用对剩余物获取和潜在再磁化的潜在影响的实验研究；并将对具体的成岩事件对磁化的影响进行详细的研究。这些研究将允许继续建立威利斯顿和加拿大西部沉积盆地再磁化分布的大陆尺度综合和数据库，旨在评估沉积盆地再磁化和剩余物获取的控制因素。

Paleomagnetic and rock magnetic studies of sedimentary basins have proven to be significant sources of information on subjects as diverse as the origin of ore deposits, the development of reversal time scales and past climate variation. As such, the importance of understanding the geologic and environmental processes that have created, modified and destroyed specific magnetization components within a basin cannot be overstated. The applicant's previous paleomagnetic and rock magnetic studies have focused on Ordovician- Mississippian carbonates of the Williston Basin in central North America. Such carbonates have provided significant information; however, they typically have weak natural magnetizations, and carry one or more secondary magnetizations that may or may not be associated with specific diagenetic events. To complicate matters even further, if the secondary magnetization is unrecognized, our understanding of the processes that occur in the basins may be affected. The studies proposed are aimed at reducing and constraining these complications, even as they continue to examine the traditional hypotheses on the origins of remagnetizations in sedimentary rocks, investigate remanence acquisition mechanisms, and evaluate some additional possible factors in remagnetization. Three new approaches to the long term objectives are being proposed: the past paleomagnetic studies of the Williston and Western Canada Sedimentary Basins will be extended to younger, clastic rocks (Cretaceous Viking Formation and equivalents), experimental investigations on the potential for fluid / temperature interaction effects on remanence acquistion and potentially remagnetization will be conducted; and a close examination of the impact of specific diagenetic events on magnetization will be performed. These studies will allow continued construction of a continental-scale synthesis and database of the distribution of remagnetizations in the Williston and Western Canada Sedimentary Basins that aims to evaulate the controlling factors on remagnetization and remanence acquisition in sedimentary basins.