Journal ArticleDOI
Orbital modulation of the Earth's magnetic field intensity
TLDR
In this paper, a spectral analysis of sedimentary records of relative geomagnetic palaeointensity from two North Atlantic sites was performed, showing significant power both at orbital eccentricity (∼100 kyr) and obliquity (41 kyr).Abstract:
More than 20 years ago, on the basis of data from a Pacific sediment core, it was suggested that geomagnetic field intensity may vary with the Earth's orbital obliquity (centred on a period of ∼41 kyr) as a result of the effect of obliquity on precessional forces in the Earth's core1 It had also been proposed that precession plays an important role in the energy budget of the Earth's geodynamo2 But subsequent analyses indicated that the energy available from precession is at least an order of magnitude less than that required to drive the geodynamo3 Here, however, we report a spectral analysis of sedimentary records of relative geomagnetic palaeointensity from two North Atlantic sites which shows significant power both at orbital eccentricity (∼100 kyr) and obliquity (41 kyr) The eccentricity power is also present in bulk magnetic properties (such as susceptibility) and is therefore attributable to lithological variations controlled by eccentricity-driven climate change The obliquity power, however, is not apparent in bulk magnetic properties, and seems to be a property of the geomagnetic field itself, thus providing evidence for the orbital forcing of geomagnetic field intensityread more
Citations
More filters
Journal ArticleDOI
Global changes in intensity of the Earth's magnetic field during the past 800kyr
TL;DR: In this article, the authors present the integration of 33 records of relative palaeointensity into a composite curve spanning the past 800 kyr and find that the intensity of the Earth's dipole field has experienced large-amplitude variations over this time period with pronounced intensity minima coinciding with known excursions in field direction, reflecting the emergence of non-dipole components.
Journal ArticleDOI
Stacking paleointensity and oxygen isotope data for the last 1.5 Myr (PISO-1500)
TL;DR: Lisiecki et al. as mentioned in this paper used the Match algorithm to simultaneously correlate isotope and RPI records, which reduced the degree of freedom associated with correlations using RPI or oxygen isotope records alone.
Journal ArticleDOI
Time variations in geomagnetic intensity
TL;DR: A significant step has been achieved by combining intensity records derived from archeological materials and from lava flows in order to extract the global field changes over the past 12 kyr.
Journal ArticleDOI
Cosmic Rays and Climate
TL;DR: In the last few years, diverse reconstructions of past climate change have revealed clear associations with cosmic ray variations recorded in cosmogenic isotope archives, providing persuasive evidence for solar or cosmic ray forcing of the climate as discussed by the authors.
Journal ArticleDOI
Geomagnetic excursions and paleointensities in the Matuyama Chron at Ocean Drilling Program Sites 983 and 984 (Iceland Basin)
TL;DR: In this article, the authors derived geomagnetic paleointensity proxies from the slope of the NRM versus anhysteretic remanent magnetization plot for alternating field demagnetization in the 30-60 mT peak field range.
References
More filters
Book
Spectral analysis and its applications
TL;DR: In this paper, Spectral Analysis and its Applications, the authors present a set of applications of spectral analysis and its application in the field of spectroscopy, including the following:
Journal ArticleDOI
Insolation values for the climate of the last 10 million years
André Berger,Marie-France Loutre +1 more
TL;DR: In this article, new values for the astronomical parameters of the Earth's orbit and rotation (eccentricity, obliquity and precession) are proposed for paleoclimatic research related to the Late Miocene, the Pliocene and the Quaternary.
Journal ArticleDOI
Age dating and the orbital theory of the ice ages: Development of a high-resolution 0 to 300,000-year chronostratigraphy
Douglas G. Martinson,Nicklas G Pisias,James D. Hays,John Imbrie,Theodore C. Moore,Nicholas J Shackleton +5 more
TL;DR: Using the concept of "orbital tuning", a continuous, high-resolution deep-sea chronostratigraphy has been developed spanning the last 300,000 yr as mentioned in this paper.
Journal ArticleDOI
Hysteresis properties of titanomagnetites: Grain-size and compositional dependence
TL;DR: In this article, the grain-size dependence of parameters with coercive force as high as 2,000 Oe in x = 0.6 titanomagnetite was found.
Journal ArticleDOI
Long-term variations of daily insolation and Quaternary climatic changes
TL;DR: In this paper, a trigonometrical formula for the Earth's orbital elements is presented, which allows direct spectral analysis and the computation of those long-term variations of the orbital elements which are of primary interest for the calculation of the insolation.