The fabric of fine-grained sediments, cored during Ocean Drilling Program Leg 149 to the Iberia Abyssal Plain, was analyzed using the method of anisotropy of magnetic susceptibility. The purposes of this study were to investigate downcore changes in magnetic fabric, and to determine paleocurrent direction. The general magnetic fabric analysis reveals an oblate shape, with Kmin axes perpendicular to the bedding plane, which is a typical sedimentary fabric. The magnetic lineation (L = Kmax/Kint) remains fairly constant throughout the section. However, the magnetic foliation structure (F = Kint /Kmin) shows distinctive variation. Several cases show sharp changes at lithostratigraphic boundaries. Poorly foliated intervals at Sites 897 and 898, where inclination of Kmin is not parallel to the bedding plane, probably resulted from postdepositional disturbance. For selected data from lithostratigraphic Unit I at Sites 897, 898, and 900, the magnetic lineation represented by the Kmax axes shows clustering indicative of paleocurrent direction. These data suggest that turbidity currents originated from the eastern continental margin of Iberia during the middle Miocene to late Pleistocene.
Date of initial receipt: 5 December 1994
Date of acceptance: 31 July 1995
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