Understanding magnetic remanence acquisition in sediments through a combined experimental and numerical approach

这是该项目的更新建议，以更好地了解沉积物如何获得磁剩余物。我们获得了独特的球形合成材料，并对其尺寸分布和磁性能进行了准确表征。我们系统地对该材料进行了多次沉积实验，结果表明，超过80%的剩余物在~100分钟内获得，最大晶粒尺寸分数的沉淀时间取决于应用领域。我们观察到一个明显的倾斜误差，归因于颗粒在沉积物-水界面的壁龛中的滚动，这是一种已经提出但从未直接观察到的机制。在我们的实验中，倾斜误差取决于应用场和沉积物浓度/沉降速率，这直接关系到颗粒的锁定效率。由于寻找合适的材料和建立必要的实验设备需要时间，我们从2010年6月开始才获得可发表的数据。现在一切都准备好了，实验也在不间断地进行，我们只需要六个月的额外资金，这将使我们能够完成正在进行的球形粒子实验，完成对椭球粒子的关键附加实验，并将结果写下来发表。

This is a renewal proposal for the project to better understand how sediments acquire a magnetic remanence. We have obtained unique spherical synthetic material whose size distribution and magnetic properties we have accurately characterized. We have systematically conducted several deposition experiments with this material showing that more than 80% of the remanence is acquired within ~100 minutes, the settling time of the largest grain size fraction, and is dependent on the applied field. We observe an appreciable inclination error, ascribed to the rolling of the particles in niches at the sediment-water interface, a mechanism that has been proposed but never directly observed. In our experiments the inclination error is dependent on the applied field and on the sediment concentration/sedimentation rate, which directly relates to the efficiency of locking-in of the particles. Due to the time it took to find the appropriate material and build the necessary experimental apparatus, we have only been acquiring publishable data since June 2010. Now that everything is in place and that the experiments are being performed uninterruptedly, we ask for only six months of additional funding which will allow us to finalize ongoing experiments on spherical particles, complete them with crucial additional experiments on ellipsoidal particles, and write up the results for publication.