METHODS

Natural remanent magnetization (NRM) was measured at 5-cm intervals on a 2-G three-axis cryogenic magnetometer aboard the JOIDES Resolution for all archive-half split-core sections from Site 1077. Alternating-field (AF) demagnetization was done using the 2-G three-axis AF demagnetizer at 10 and 20 mT to remove overprinting from the coring process. U-channels were collected from the composite splice for Site 1077 from 0 to 40 meters composite depth (mcd) and measured 16 months postcruise. Natural and laboratory-induced remanent magnetizations were measured at 1-cm intervals on a 2-G three-axis cryogenic magnetometer at the Geological Survey of Japan. NRM was measured after AF demagnetization at 20, 30, 40, 50, 60, and 80 mT using the three-axis AF demagnetizing coils on the 2-G magnetometer.

Several laboratory-induced magnetic remanences were also measured on the U-channels. Anhysteretic remanent magnetization (ARM) was applied in a 100-mT demagnetizing field with a 0.1-mT direct current (DC) biasing field. Saturation isothermal remanent magnetization (SIRM) was applied using a 1.8-m-long solenoid 2-G pulse magnetizer with fields of +1 and -0.3 T with measurements taken after each treatment.

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