Intensity-Inclination Correlation for Long-Term Secular Variation of the Geomagnetic Field and Its Relevance to Persistent Non-Dipole Components

Isolating climatic and paleomagnetic imbricated signals in two marine cores using principal component analysis

“…The elastic rebound results in an upward movement of the piston forcing sediments to penetrate the core barrel in excess [Széréméta et al, 2004]. A similar oversampling effect has been reported for the upper part of cores MD98-2183, MD98-2185 and MD98-2187 collected in the West Caroline Basin [Yamazaki and Oda, 2004]. The oversampled interval has not been considered in the present study.…”

“…Different orbital frequencies have been reported by various authors who performed spectral analyses of paleomagnetic directions and paleointensity variations recorded in marine sedimentary cores. Previous studies in the Caroline basin [ Yamazaki and Oda , 2002, 2004, 2005; Yokoyama et al , 2007; Yamazaki et al , 2008] have pointed out the contribution of a 100 ka periodicity in the inclination as well as in paleointensity records of several marine cores [ Thouveny et al , 2008]. Despite the fact that we found it conceptually difficult to imagine the physical process by which changes in the eccentricity of the Earth's orbit could influence the geodynamo, this area was appropriate for testing further the relation between the orbital parameters and the magnetization of the sediment.…”

“…The choice of core MD98‐2182 was also guided by the existence of previous magnetic studies in the same area involving cores MD98‐2183, MD98‐2185 and MD98‐2187 [ Yokoyama and Yamazaki , 2000; Yamazaki and Oda , 2002; Yamazaki and Oda , 2004; Yamazaki and Oda , 2005; Yokoyama et al , 2007]. A major characteristic reported from these measurements is the existence of a 100 ka periodicity in the inclination and intensity signals persisting over the last 2.5 Myr.…”