Geomagnetic intensity variations for the past 8 kyr: New archaeointensity results from Eastern China

Cai, Shenshen; Tauxe, Lisa; Deng, Chenglong; Pan, Yongxin; Gao, Jin; Zheng, J. Q.; Xie, Fei; Qin, Huafeng; Zhu, Rixiang

doi:10.1016/j.epsl.2014.02.030

Cited by 33 publications

(47 citation statements)

References 71 publications

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“…These high values are in agreement with recently published data by Shaar et al (4) and represent one of the Levantine Iron Age "geomagnetic spikes." These anomalies, first reported by Ben-Yosef et al (2), were defined by Cai et al (32) as "a sharp increase in the field intensity to more than twice the present value (∼160 ZAm 2 VADM) in less than 500 years." Following this definition and the current data available for the Levant (4), there is evidence for at least two such spikes, one during the 10th century BCE [cf.…”

Section: Discussionmentioning

confidence: 93%

Six centuries of geomagnetic intensity variations recorded by royal Judean stamped jar handles

Ben‐Yosef

Millman

Shaar

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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Earth's magnetic field, one of the most enigmatic physical phenomena of the planet, is constantly changing on various time scales, from decades to millennia and longer. The reconstruction of geomagnetic field behavior in periods predating direct observations with modern instrumentation is based on geological and archaeological materials and has the twin challenges of (i) the accuracy of ancient paleomagnetic estimates and (ii) the dating of the archaeological material. Here we address the latter by using a set of storage jar handles (fired clay) stamped by royal seals as part of the ancient administrative system in Judah (Jerusalem and its vicinity). The typology of the stamp impressions, which corresponds to changes in the political entities ruling this area, provides excellent age constraints for the firing event of these artifacts. Together with rigorous paleomagnetic experimental procedures, this study yielded an unparalleled record of the geomagnetic field intensity during the eighth to second centuries BCE. The new record constitutes a substantial advance in our knowledge of past geomagnetic field variations in the southern Levant. Although it demonstrates a relatively stable and gradually declining field during the sixth to second centuries BCE, the new record provides further support for a short interval of extreme high values during the late eighth century BCE. The rate of change during this "geomagnetic spike" [defined as virtual axial dipole moment > 160 ZAm 2 (10 21 Am 2 )] is further constrained by the new data, which indicate an extremely rapid weakening of the field (losing ∼27% of its strength over ca. 30 y).archaeomagnetism | archaeointensity | levantine archaeomagnetic curve | paleosecular variation | archaeomagnetic spikes R econstruction of geomagnetic secular variation during the Holocene has implications for various fields of research, from geophysics and other planetary sciences to biology and archaeology. Such reconstructions are based predominantly on heatimpacted geological and archaeological materials, whose thermal remanent magnetization (TRM) holds information on the geomagnetic field vector at the time of their last cooling. As evidence for fluctuating field behavior, including short (decadal) periods of rapid changes, is constantly growing (1-5), using records with excellent time resolution has become increasingly of interest.To improve the accuracy and precision of age constraints associated with estimates of ancient geomagnetic field strength, the current study exploits a set of archaeological artifacts whose ages are exceptionally well constrained. This set is composed of wellstudied ceramic jars from Judah/Yehud/Judea (Jerusalem and its vicinity), which bear royal stamp impressions on their handles (6-10). The stamped jars were part of the ancient administration of this region for about 600 y, between the late eighth and late second centuries BCE. As the types of stamp impressions changed with time according to the political situation, the jar handles provide an excellent recor...

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Section: Discussionmentioning

confidence: 93%

Six centuries of geomagnetic intensity variations recorded by royal Judean stamped jar handles

Ben‐Yosef

Millman

Shaar

et al. 2017

Proc. Natl. Acad. Sci. U.S.A.

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“…Necessity of the cooling rate correction has also been emphasized in many studies because the difference in that rate could result in biased archeointensity estimates (e.g., Mitra et al 2013;Cai et al 2014). For example, Usui (2013) reported that the cooling rate effect resulted in a 37% to 46% overestimated paleointensity for an oceanic gabbro, although it is not the case of the archeointensities.…”

Section: Discussionmentioning

confidence: 99%

“…In contrast, brand new data with modern paleointensity techniques have been published from East Asia outside Japan, for example, Korea (Yu et al 2010;Hong et al 2013) and China (Cai et al 2014). In 1960s to 1970s, a group of Japanese researchers had made systematic oriented-sample collections from baked clay at many pottery kilns excavated in and around Sakai city, Osaka prefecture, Japan.…”

Section: Introductionmentioning

confidence: 99%

Archeointensity study on baked clay samples taken from the reconstructed ancient kiln: implication for validity of the Tsunakawa-Shaw paleointensity method

Yamamoto

Torii

Natsuhara³

2015

Earth Planet Sp

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In 1972, a reconstruction experiment of a kiln had been done to reproduce an excavated kiln of the seventh century in Japan. Baked clay samples were taken from the floor surface and −20 cm level, and they have been stored after determinations of the paleomagnetic directions by partial alternating field demagnetizations. We recently applied the Tsunakawa-Shaw method to the samples to assess how reliable archeointensity results are obtained from the samples. A suite of the rock magnetic experiments and the scanning electron microscope observations elucidate that dominant magnetic carriers of the floor surface samples are Ti-poor titanomagnetite grains in approximately 10 nm size with single-domain and/or super-paramagnetic states, whereas contributions of multi-domain grains seem to be relatively large for the −20-cm level samples. From the floor surface samples, six out of the eight successful results were obtained and they give an average of 47.3 μT with a standard deviation of 2.2 μT. This is fairly consistent with the in situ geomagnetic field of 46.4 μT at the time of the reconstruction. They are obtained with a built-in anisotropy correction using anhysteretic remanent magnetization and without any cooling rate corrections. In contrast, only one out of four was successful from the −20-cm level samples. It yields an archeointensity of 31.6 μT, which is inconsistent with the in situ geomagnetic field. Considering from the in situ temperature record during the firing of the kiln and the unblocking temperature spectra of the samples, the floor surface samples acquired full thermoremanent magnetizations (TRMs) as their natural remanent magnetizations whereas the −20-cm level samples only acquired partial TRMs, and these differences probably cause the difference in the archeointensity results between the two sample groups. For archeointensity researches, baked clay samples from a kiln floor are considered to be ideal materials.

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“…Here we used the GEOMAGIA50.v3 database (Donadini et al 2006;Korhonen et al 2008;Brown et al 2015) to which we added recent archeo-and paleointensity results (Cai et al 2014(Cai et al , 2015Cromwell et al 2015;de Groot et al 2015;Di Chiara et al 2014;Gallet et al 2008Gallet et al , 2009Gallet & Al Maqdissi 2010;Hong et al 2013;Kapper et al 2015;Kissel et al 2015;Osete et al 2015;Shaar et al 2015;Stillinger et al 2015). Concerning the data compiled in this version of GEOMAGIA, the Mesopotamian data from Nachasova & Burakov (1995 were modified according to .…”

Section: Appendix A: Gmag9k Axial Dipole Evolutionmentioning

confidence: 99%

Solar activity during the Holocene: the Hallstatt cycle and its consequence for grand minima and maxima

Usoskin

Gallet

Lopes

et al. 2016

A&A

131

183

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Aims. Cosmogenic isotopes provide the only quantitative proxy for analyzing the long-term solar variability over a centennial timescale. While essential progress has been achieved in both measurements and modeling of the cosmogenic proxy, uncertainties still remain in the determination of the geomagnetic dipole moment evolution. Here we aim at improving the reconstruction of solar activity over the past nine millennia using a multi-proxy approach. Methods. We used records of the 14 C and 10 Be cosmogenic isotopes, current numerical models of the isotope production and transport in Earth's atmosphere, and available geomagnetic field reconstructions, including a new reconstruction relying on an updated archeo-and paleointensity database. The obtained series were analyzed using the singular spectrum analysis (SSA) method to study the millennial-scale trends. Results. A new reconstruction of the geomagnetic dipole field moment, referred to as GMAG.9k, is built for the last nine millennia. New reconstructions of solar activity covering the last nine millennia, quantified in terms of sunspot numbers, are presented and analyzed. A conservative list of grand minima and maxima is also provided. Conclusions. The primary components of the reconstructed solar activity, as determined using the SSA method, are different for the series that are based on 14 C and 10 Be. This shows that these primary components can only be ascribed to long-term changes in the terrestrial system and not to the Sun. These components have therefore been removed from the reconstructed series. In contrast, the secondary SSA components of the reconstructed solar activity are found to be dominated by a common ≈2400-year quasi-periodicity, the so-called Hallstatt cycle, in both the 14 C and 10 Be based series. This Hallstatt cycle thus appears to be related to solar activity. Finally, we show that the grand minima and maxima occurred intermittently over the studied period, with clustering near lows and highs of the Hallstatt cycle, respectively.

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Geomagnetic intensity variations for the past 8 kyr: New archaeointensity results from Eastern China

Cited by 33 publications

References 71 publications

Six centuries of geomagnetic intensity variations recorded by royal Judean stamped jar handles

Six centuries of geomagnetic intensity variations recorded by royal Judean stamped jar handles

Archeointensity study on baked clay samples taken from the reconstructed ancient kiln: implication for validity of the Tsunakawa-Shaw paleointensity method

Solar activity during the Holocene: the Hallstatt cycle and its consequence for grand minima and maxima

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