Magnetic fabric of bioturbated sediment from the northern Rockall Trough: Comparison with modern currents

Magnetic fabric characteristics of bioturbated wave‐produced grain orientation in the Bridport‐Yeovil Sands (Lower Jurassic) of Southern England

“…The lineations are not appreciably different between the bioturbated and nonbioturbated lithologies, an observation which is not unique, since other studies have shown that bioturbated sediments may show a 'primary' type of magnetic fabric preserving the lineation (e.g. Rees et al, 1982). However, these studies were different in respect that the magnetic fabric is carried by titanomagnetite, in contrast to the paramagnetic carriers in this study.…”

Enhanced deepwater circulation and shift of sedimentary organic matter oxidation pathway in the Okinawa Trough since the Holocene

“…Following KC intensification event and massive increase in sediment supply, the iK max values increase abruptly and reach a maximum (∼80°) at 8.7–6.6 cal ka BP. Bioturbation, magnetic grain size, mineralogy, or coring disturbances can cause changes in magnetic fabric patterns [ Rees et al , 1982; Thouveny et al , 2000]. The ChRM inclinations (Inc ChRM ; Figure 2c) have a mean of 33 ± 14°, which is close to but shallower than the expected value (43°) at ∼25°N.…”

The magnetic fabric of surficial deep-sea sediments in the HEBBLE area (Nova Scotian continental rise).

“…Many workers have used the orientation of km~ X as an indication of the direction of sediment transport by bottom currents in the deep sea (Rees et al, 1968;Ledbetter, 1977, 1979;Ellwood, 1979Ellwood, , 1980aLedbetter and EUwood, 1980;Auffret et al, 1981;Rees et al, 1982;Shot et al, 1984). In most of these studies the kraax orientation was thought to be parallel to the current direction, although in some instances the k~a x alignment was perpendicular to the bottom current direction (e.g., Ellwood and Ledbetter, 1977;Ellwood, 1979).…”

“…Secondary fabrics have been recognized which result from post-depositional alteration of primary fabric. Deformed fabrics in deep-sea sediments often result from the activity of burrowing organisms in the sediment (Rees et al, 1968;Rees et al, 1982) or due to coring disturbance (Rees and Frederick, 1974;Kent and Lowrie, 1975). Auffret et al (1981) and Ellwood (1979) noted the possibility of other kinds of primary fabric from deposition by flowing currents.…”

“…As part of a wider study of deep-sea sedimentary fabric, we measured the anisotropy of magnetic susceptibility (AMS) of surficial sediments from the HEBBLE (High Energy Benthic Boundary Layer Experiment) area on the Nova Scotian continental rise. The alignment of magnetic grains, which gives rise to AMS is thought to be representative of the alignment of other grains in the sample (Hamilton and Rees, 1970), and the fabric of these grains has been used to infer the direction of paleocurrents and the nature of sedimentation conditions in various regions of the world ocean (Rees et al, 1968;Ledbetter, 1977, 1979;Ellwood, 1979Ellwood, , 1980aLedbetter and Ellwood, 1980;Auffret et al, 1981;Rees et al, 1982;Bullfinch et al, 1982;Shor et al, 1984). We measured magnetic fabric of sediments from the HEBBLE area, a well-surveyed, well-studied, and heavily instrumented region of the Nova Scotian rise, to attempt to relate the fabric of the surficial sediments to modern depositional conditions.…”