Remagnetization and fluids



Remagnetization, the acquisition of a secondary magnetization, is accepted as a widespread phenomenon in sedimentary rocks. The recognition that many sedimentary rocks were partially or completely remagnetized long after deposition has not only led to a reevaluation of the paleomagnetic data base [for example, Van der Voo, 1989], but has also led to a new application of paleomagnetism to other areas of Earth science. Most remagnetizations are caused by the precipitation of authigenic magnetic phases, the replacement of precursor minerals, or uplift and cooling after prolonged heating. Isolation of a secondary magnetization and comparison of the corresponding pole position to the apparent polar wander path, therefore, can provide essential constraints on the timing of secondary events. Many remagnetizations are tangible evidence of a chemical (for example, diagenetic) event caused by rock-fluid interactions, and recent studies have demonstrated the potential for using chemical remagnetizations to constrain the timing of diagenetic events.