Abstract
Marine sediments provide valuable information for a continuous geological record. Piston-type corers (conventional piston corer, and Integrated Ocean Drilling Program piston corer such as Advanced Piston Core System) are commonly used to collect sediments from the seafloor. The piston-type corer can recover a relatively longer sequence of sediment than that collected by a gravity-type corer. It owes a negative pressure produced by piston-system which makes sediment entering easier into tubes. However an inappropriate working of piston system will result in disturbing the texture and structure of sediment core. The disturbance possibly makes alternations on basic parameters such as length and physical properties. Although the disturbance is invisible sometimes, it can be detected by magnetic remanent directions and anisotropy of magnetic susceptibility.
