Results 21 to 30 of about 181 (155)

An activity index for geomagnetic paleosecular variation, excursions, and reversals [PDF]

Geochemistry, Geophysics, Geosystems, 2017
AbstractMagnetic indices provide quantitative measures of space weather phenomena that are widely used by researchers in geomagnetism. We introduce an index focused on the internally generated field that can be used to evaluate long term variations or climatology of modern and paleomagnetic secular variation, including geomagnetic excursions, polarity ...
S. Panovska, C. G. Constable
openaire   +3 more sources

Full‐Vector Paleosecular Variation Curve for the Azores: Enabling Reliable Paleomagnetic Dating for the Past 2 kyr [PDF]

Journal of Geophysical Research: Solid Earth, 2021
AbstractFor archeomagnetic dating, high‐quality directional and intensity paleosecular variation curves are needed. The Azores Archipelago in the mid‐Atlantic Ocean provides a wealth of volcanic products erupted during the Holocene, making it an ideal location to (1) gather paleomagnetic data from well dated lava flows and (2) construct a paleosecular ...
Annemarieke Béguin, Adriano Pimentel, Lennart V. de Groot   +2 more
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Paleosecular variation and the average geomagnetic field at ±20° latitude [PDF]

Geochemistry, Geophysics, Geosystems, 2006
We assembled a new paleomagnetic directional data set from lava flows and thin dikes for four regions centered on ±20° latitude: Hawaii, Mexico, the South Pacific, and Reunion. We investigate geomagnetic field behavior over the past 5 Myr and address whether geographical differences are recorded by our data set.
K. P. Lawrence, C. G. Constable, C. L. Johnson   +2 more
openaire   +1 more source

Consistent and Contrasting Aspects of the Geomagnetic Field Across Epochs With Distinct Reversal Frequencies Revealed by Modeling the Kiaman Superchron

Geochemistry, Geophysics, Geosystems, 2021
This work presents an extensive directional paleomagnetic database of the Kiaman reversed superchron. It is composed of 1,459 paleomagnetic directions from igneous rocks corresponding to 91 data sets (or paleomagnetic poles).
Daniele Brandt, Marcia Ernesto, Catherine Constable   +2 more
doaj   +1 more source

Persistent shallow magnetic inclination in the past 5 million years with implications for regional tectonics in the Philippines

Journal of Asian Earth Sciences: X, 2021
Despite the growing knowledge on geomagnetic paleosecular variations, the region around the Philippine archipelago remains to be a huge data gap in this regard. This work looked into rock magnetic information from
Decibel V. Faustino-Eslava, Hidetoshi Shibuya, Carla B. Dimalanta, Graciano P. Yumul, Jr., Jonathan T. Macuroy   +4 more
doaj   +1 more source

More stable yet bimodal geodynamo during the Cretaceous superchron?

Geophysical Research Letters, 2016
We report palaeomagnetic and 40Ar/39Ar dating results from two sequences of basaltic lava flows deposited at the same locality in western China, yet separated in time by ~50 Myr: one set lies within the Cretaceous normal superchron at 112–115 Ma and a ...
Florian Lhuillier, Stuart A. Gilder, Michael Wack, Kuang He, Nikolai Petersen, Brad S. Singer, Brian R. Jicha, Allen J. Schaen, Dylan Colon   +8 more
doaj   +1 more source

Constraints on Brunhes low-latitude paleosecular variation Iztaccihuatl stratovolcano, basin of Mexico

Geofísica Internacional, 1995
Los datos paleomagnéticos para lavas del volcán Iztaccíhuatl permiten analizar la variación paleosecular del campo geomagnético en la región central de Mexico.
Jaime Urrutia-Fucugauchi
doaj   +1 more source

New Archeomagnetic Directional Records From Iron Age Southern Africa (ca. 425–1550 CE) and Implications for the South Atlantic Anomaly

Geophysical Research Letters, 2018
The paucity of Southern Hemisphere archeomagnetic data limits the resolution of paleosecular variation models. At the same time, important changes in the modern and historical field, including the recent dipole decay, appear to originate in this region ...
Vincent J. Hare, John A. Tarduno, Thomas Huffman, Michael Watkeys, Phenyo C. Thebe, Munyaradzi Manyanga, Richard K. Bono, Rory D. Cottrell   +7 more
doaj   +1 more source

Mapping the Gauss Coefficients to the Pole and the Models of Paleosecular Variation.

Journal of geomagnetism and geoelectricity, 1995
The present magnetic field is usually described by models such as the IGRF which are described by Gauss coefficients obtained by spherical harmonic analysis of the geomagnetic field. The use of Gauss coefficients in paleosecular variation (PSV) studies will therefore make it possible to compare field structures obtained through paleomagnetism with ...
Kono, Masaru, Tanaka, Hidefumi
openaire   +2 more sources

Paleomagnetic evidence for episodic construction of the Mamiyadake tephra ring

Earth, Planets and Space, 2023
Tephra rings that surround maar craters are typically inferred from field observations to have been emplaced rapidly over a time period of days to years and thus monogenetic, which is, however, rarely assessed quantitatively.
Yuki Yasuda
doaj   +1 more source