Absolute geomagnetic intensity determinations on Formative potsherds (1400–700 BC) from the Oaxaca Valley, Southwestern Mexico

AbstractNew Thellier-Coe archeointensity determinations have been measured on 15 potsherds from the Oaxaca Valley belonging to three of the four Formative Periods (Pre-Classical) of Mesoamerica, spanning 1400–700 BC. Seven of these are considered to be reliable and indicate a geomagnetic field strength of about 30 μT. This value is some 75% of the present geomagnetic field strength but is in agreement with the absolute intensities predicted from global models for this time and location, and consistent with coeval published determinations. These data thus provide significant evidence for the geomagnetic field strength in an area and for a time that was previously poorly constrained, thus providing an important contribution towards establishing a local master curve for the last 3500 yr. When established, such a curve would be a useful dating tool and also enable establishing for field strength correlations with climatic events and civilization evolutions in a region that is particularly strong in archeological and geological features. Such potential is examined for aridity events, although such observations can only be considered tentative at this stage.

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Variations in the geomagnetic field strength in the 5th–3rd centuries BC in the eastern Mediterranean (according to narrowly dated ceramics)

Geomagnetism and Aeronomy ◽

10.1134/s0016793208030158 ◽

2008 ◽

Vol 48 (3) ◽

pp. 408-414 ◽

Cited By ~ 3

Author(s):

I. E. Nachasova ◽

K. S. Burakov ◽

T. A. Il’ina

Keyword(s):

Field Strength ◽

Geomagnetic Field ◽

Eastern Mediterranean ◽

Geomagnetic Field Strength

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A tectonomagnetic effect detected in Central Italy

Annals of Geophysics ◽

10.4401/ag-4233 ◽

1994 ◽

Vol 37 (1) ◽

Author(s):

G. Mele ◽

A. Meloni ◽

P. Palangio

Keyword(s):

Field Intensity ◽

Geomagnetic Field ◽

Central Italy ◽

Volcanic Eruptions ◽

Intensity Data ◽

Absolute Level ◽

Tectonic Events ◽

Railway System ◽

The Absolute ◽

Geomagnetic Intensity

Significant variations in the absolute value of the geomagnetic field intensity related to tectonic events, as earthquakes and volcanic eruptions, have been observed in several cases. To detect such a tectonomagnetic effect related to seismic activity, a seismomagnetic network was installed by the Istituto Nazionale di Geofisica (ING) in the Abruzzi region (CentraI Italy), in July 1989. This area is being uplifting since the Pliocene. A logistic compromise between geophysical requirements and the electrified railway system tracks distribution led to the installation of five total magnetic field intensity data acquisition sites. From July 1989 to September 1992 geomagnetic intensity data were simultaneously recorded at all stations and compared to that recorded at the L'Aquila Observatory, located in the same area. A variation of about 10 nT in the absolute level of the geomagnetic field was measured at two stations located on the eastern side of the network. We suggest that the detected magnetic anomaly could resuIt from aseismic-changes in crustal stress during this time.

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The paleomagnetism of single silicate crystals: Recording geomagnetic field strength during mixed polarity intervals, superchrons, and inner core growth

Reviews of Geophysics ◽

10.1029/2005rg000189 ◽

2006 ◽

Vol 44 (1) ◽

Cited By ~ 79

Author(s):

J. A. Tarduno ◽

R. D. Cottrell ◽

A. V. Smirnov

Keyword(s):

Field Strength ◽

Geomagnetic Field ◽

Inner Core ◽

Mixed Polarity ◽

Geomagnetic Field Strength ◽

Inner Core Growth

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Instability of thermoremanence and the problem of estimating the ancient geomagnetic field strength from non-single-domain recorders

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1507986112 ◽

2015 ◽

Vol 112 (36) ◽

pp. 11187-11192 ◽

Cited By ~ 6

Author(s):

Ron Shaar ◽

Lisa Tauxe

Keyword(s):

Magnetic Field ◽

Field Strength ◽

Geomagnetic Field ◽

Single Domain ◽

Standard Theory ◽

Systematic Bias ◽

The Past ◽

Deep Interior ◽

Relationship Of ◽

Geomagnetic Field Strength

Data on the past intensity of Earth’s magnetic field (paleointensity) are essential for understanding Earth’s deep interior, climatic modeling, and geochronology applications, among other items. Here we demonstrate the possibility that much of available paleointensity data could be biased by instability of thermoremanent magnetization (TRM) associated with non-single-domain (SD) particles. Paleointensity data are derived from experiments in which an ancient TRM, acquired in an unknown field, is replaced by a laboratory-controlled TRM. This procedure is built on the assumption that the process of ancient TRM acquisition is entirely reproducible in the laboratory. Here we show experimental results violating this assumption in a manner not expected from standard theory. We show that the demagnetization−remagnetization relationship of non-SD specimens that were kept in a controlled field for only 2 y show a small but systematic bias relative to sister specimens that were given a fresh TRM. This effect, likely caused by irreversible changes in micromagnetic structures, leads to a bias in paleointensity estimates.

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The relationship between 10Be and geomagnetic field strength records in central North Atlantic sediments during the last 80 ka

Earth and Planetary Science Letters ◽

10.1016/0012-821x(95)00202-n ◽

1995 ◽

Vol 136 (3-4) ◽

pp. 551-557 ◽

Cited By ~ 63

Author(s):

Christian Robinson ◽

Grant M. Raisbeck ◽

Françoise Yiou ◽

Benoiˆt Lehman ◽

Carlo Laj

Keyword(s):

Field Strength ◽

North Atlantic ◽

Geomagnetic Field ◽

The Relationship ◽

Geomagnetic Field Strength

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Effects of thermally heterogeneous structure in the lowermost mantle on the geomagnetic field strength

Earth and Planetary Science Letters ◽

10.1016/j.epsl.2008.06.017 ◽

2008 ◽

Vol 272 (3-4) ◽

pp. 738-746 ◽

Cited By ~ 34

Author(s):

F. Takahashi ◽

H. Tsunakawa ◽

M. Matsushima ◽

N. Mochizuki ◽

Y. Honkura

Keyword(s):

Field Strength ◽

Geomagnetic Field ◽

Heterogeneous Structure ◽

Geomagnetic Field Strength ◽

Lowermost Mantle

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Geomagnetic field strength 3.2 billion years ago recorded by single silicate crystals

Nature ◽

10.1038/nature05667 ◽

2007 ◽

Vol 446 (7136) ◽

pp. 657-660 ◽

Cited By ~ 87

Author(s):

John A. Tarduno ◽

Rory D. Cottrell ◽

Michael K. Watkeys ◽

Dorothy Bauch

Keyword(s):

Field Strength ◽

Geomagnetic Field ◽

Geomagnetic Field Strength

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Geomagnetic Field Strength Recorded in Iron Age Ceramics from Southern Africa

10.3997/2214-4609-pdb.241.watkeys_paper ◽

2009 ◽

Author(s):

Michael Watkeys ◽

John A. Tarduno ◽

Thomas Huffman ◽

Rory D. Cottrell ◽

Julia Voronov ◽

...

Keyword(s):

Field Strength ◽

Iron Age ◽

Southern Africa ◽

Geomagnetic Field ◽

Geomagnetic Field Strength

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Improving the measurement accuracy of magnetometer algorithmic correction of its instrumental errors

Izmeritel`naya Tekhnika ◽

10.32446/0368-1025it.2020-5-50-57 ◽

2020 ◽

pp. 50-57

Author(s):

Yury G. Astrakhantsev ◽

Nadezhda A. Beloglazova

Keyword(s):

Field Strength ◽

Geomagnetic Field ◽

Field Tests ◽

Magnetic Method ◽

Special Equipment ◽

Geomagnetic Variations ◽

Functional Scheme ◽

Accuracy Of Measurements ◽

Geomagnetic Field Strength ◽

Three Components

In many applications of the magnetic method it is advantageous to have information about the geomagnetic field strength and its gradients. The direct measurement of gradients does not depend on geomagnetic variations or normal field values. Special equipment is required for this purpose. The results of the development and construction of a three-component magnetometer-gradiometer are presented. The device is designed to measure on the earth's surface the absolute values of the three components of the geomagnetic field vector and the corresponding three components of the gradient. Installation of additional measuring sensors in the device – accelerometers, allows you to calculate the orientation of these vectors in space. The device of a magnetometer-gradiometer is described, its functional scheme and operating principle are presented. A set of instrumental errors that occur in the manufacture of three-axis systems of ferrosondes and accelerometers for measuring the components of the geomagnetic field strength and determining the orientation of the device is considered. The paper presents a method for determining instrumental errors and algorithmic correction of information signals coming from measuring sensors to significantly improve the accuracy of measurements. Examples of field tests of the device are given. The presented magnetometer-gradiometer can be used for accurate localization of previously identified ore bodies and determining the details of their structure.

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