9726884 Housen Marine sediments can provide continous records of geomagnetic field behavior that connot be obtained from continental sediments or volcanic rocks. Single-magnetic-domain particles of magnetite produced by magnetotactic bacteria have been proposed as important recorders of magnetization in marine sediments. Yet, the role of biogenic magnetite in the magnetization process remains poorly understood. The P. I.s will conduct a series of experiments based upon recent advances in rock-magnetism designed to measure the abundance and orientation-distribution of magnetofossils in marine sediments. These experiments will help to establish the role (or lack thereof) of magnetofossils as remanence carriers, links between magnetotactic bacteria and sediment redox, the degree of magnetofossil preservation, and the inter-relationships between these factors and the lock-in of magnetic remanence in marine sediments. ***