Results 171 to 180 of about 4,431,213 (212)

Paleosecular variation in Northern Patagonia recorded by 0-5 Ma Caviahue-Copahue lava flows

Geophysical Journal International, 2023
Paleosecular variation determinations and studies of the geometry of the Earth’s main magnetic field provide important information about the field evolution, and to constrain numerical geodynamo models.
Thiago R. Moncinhatto, W. P. de Oliveira, M. Haag, G. Hartmann, J. Savian, Wilbor Poletti, D. Brandt, C. Sommer, A. Caselli, R. Trindade   +9 more
semanticscholar   +1 more source

Polarity Transitions, Excursions and Paleosecular Variation of the Earth's Magnetic Field

Reviews of Geophysics, 1991
BRADFORD M. CLEMENT, CATHY G. CONSTABLE
openaire   +3 more sources

Paleosecular variations from lake sediments

Reviews of Geophysics, 1979
We have known since at least the 16th century that the Earth's magnetic field varies with time as well as geographic position. This secular variation (SV), which has been monitored instrumentally at various locations since that time, is fundamentally important to a complete understanding of the geomagnetic field and its origin.
S. P. Lund, S. K. Banerjee
openaire   +1 more source

Shape analysis of paleosecular variation data

Journal of Geophysical Research, 1974
Shape analysis of paleosecular variation (PSV) data, if it is properly used, can determine the statistical character of a PSV data set in many cases. Existing statistical techniques, such as the χ2 goodness of fit test, the ‘dipole moment,’ and eigenvalue methods, are reviewed with this point in mind.
Czang-Go Baag, C. E. Helsley
openaire   +1 more source

Dipole/quadrupole family modeling of paleosecular variation

Journal of Geophysical Research: Solid Earth, 1988
Contrary to previous claims that the VGP scatter and its latitude variation deduced from the present field are atypical of those for the past 5 m.y., it is shown that it is in fact typical when correctly calculated. A simple and effective model for the paleosecular variation of lavas is developed by using this important observation together with the ...
P. L. McFadden, R. T. Merrill, M. W. McElhinny   +2 more
openaire   +1 more source

Paleosecular variation during sequential geomagnetic reversals from Hawaii

Earth and Planetary Science Letters, 1999
Abstract Paleomagnetic directions measured from 175 flows in four volcanic sequences on the island of O'ahu (Hawaii) cover about 0.3 m.y. of geomagnetic field changes and include detailed records of the successive Gilbert-Gauss (3.57 Ma) and Lower Mammoth reversals (3.33 Ma).
Emilio Herrero-Bervera, Jean-Pierre Valet   +1 more
openaire   +1 more source

Paleosecular variation of field intensities and dipole moments

Earth and Planetary Science Letters, 1996
Abstract In order to use paleointensity data for paleosecular variation studies, we first obtain analytical for the intensity of the geomagnetic field and the corresponding dipole moment in terms of Gauss coefficients. Next, statistical parameters for these quantities are derived under the assumption that Gauss coefficients vary randomly with time ...
Masaru Kono, Osamu Hiroi
openaire   +1 more source

The Holocene paleosecular variation record from Elk Lake, Minnesota

Journal of Geophysical Research: Solid Earth, 1989
The paleosecular variation record of the geomagnetic field from Elk Lake, Minnesota, is presented and its implications are discussed. The Elk Lake record is compiled from measurements of four parallel cores with a 2 cm sampling interval (≈15 years).
Donald R. Sprowl, Subir K. Banerjee
openaire   +1 more source

Geomagnetic paleosecular variation in Easter Island, the southeast Pacific

Physics of the Earth and Planetary Interiors, 1998
Abstract We collected more than 250 samples from 45 sites in lava flows of the three volcanoes on Easter Island. The K–Ar whole rock dating was attempted on 13 sites. All of the ages obtained are younger than 0.8 Ma. Reliable paleomagnetic directions were obtained from 34 sites.
Masako Miki, Hiroo Inokuchi, Satoru Yamaguchi, Jun-ichi Matsuda, Keisuke Nagao, Nobuhiro Isezaki, Katsumi Yaskawa   +6 more
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Correcting distorted paleosecular variation in late glacial lacustrine clay

Physics of the Earth and Planetary Interiors, 2008
Abstract An undisturbed, horizontal chronostratigraphic marker horizon of laminated red glacio-lacustrine clay crops out over ∼25,000 km 2 in northern Ontario, Canada. The primary, clastic hematite laminae possess two stable vector components of magnetization. We sampled a 1.6 m vertical section at overlapping 2 cm intervals in cubic specimens (8 cm
G.J. Borradaile, B.S. Almqvist
openaire   +1 more source