The Magnetization Mechanism of Sediments and Sedimentary Rocks: Depositional Remanent Magnetization - Paleomagnetism of Sedimentary Rocks: Process and Interpretation - page 21

Fig. 2.4 Magnetic remanence fabrics for magnetite-bearing sedimentary rocks. The Northumberland Formation is part of
the Cretaceous Nanaimo Group of British Columbia, the Paleocene Nacimiento Formation is on the Colorado Plateau in New
Mexico and the Cretaceous Holz Shale of the Ladd and Williams Formation and the Point Loma Formation are from southern
California. In all stereonet plots the minimum principal anisotropy of anhysteretic remanence (AAR) axes are perpendicular
to the bedding plane and shown by circles (fi lled/unfi lled); the maximum (squares) and intermediate (triangles) principal axes
lie in the bedding plane. Figures from Kim & Kodama (2004) for the Northumberland Formation, from Kodama (1997) for the
Nacimiento Formation and from Tan & Kodama (1998) for the Holz Shale and Point Loma Formations.

netized particles in the sample. In these experiments,
Tauxe et al . provide evidence for fl occulation control-
ling the DRM so this is the mechanism for reduction in
DRM alignment from perfectly aligned grains (DRM
saturation).
Tan et al . (2002) conducted re - deposition experi-
ments with sediments reconstituted from the Eocene
Suweiyi Formation red beds of central China. The
purpose of Tan et al . was to see if synthetically induced
depositional- and compaction-caused inclination shal-
lowing in hematite-bearing rocks could be detected

and corrected by a single component IRM applied at
45° to the vertical. However, Tan et al . also provide
DRM: SIRM ratios for hematite-bearing sediments. Tan
et al . ' s hematite laboratory DRMs range 30 - 70 mA/m,
while an IRM applied to this rock in a 1.3 T fi eld is
6.5 A/m. Even though the rock is not magnetically
saturated at this fi eld, the IRM acquisition curves indi-
cate it is close to saturation. The DRM: IRM ratios of
0.5-1.0% are much smaller than what Tauxe et al .
observed; however, Tauxe et al . applied SIRMs to their
sediments before re-deposition while Tan et al . did not.