Recent Advances in Environmental Magnetism and Paleomagnetism

Editorial Board (June 2016)
Editor-in-Chief
Yasuo Ogawa, Tokyo Institute of Technology, Japan

Vice Editors-in-Chief
Masato Furuya, Hokkaido University, Japan
Solid Earth Science

Nozomu Nishitani, Nagoya University, Japan
Space Science

Editors
Yosuke Aoki
Nanan Balan
Stephen Bannister
Shanaka de Silva
Koji Fukuma
Lin-Ni Hau
Hauke Hussmann
Attila Komjathy

Alexey Kuvshinov
Takuto Maeda
Koji Matsumoto
Mitsuhiro Nakagawa
Junichi Nakajima
Yasuhiro Nariyuki
Azusa Nishizawa
Keiji Ohtsuki

Taku Ozawa
Takeshi Sakanoi
Martha K. Savage
Benoit Taisne
Hiroshi Takenaka
Hiroaki Toh
Yih-Min Wu
Akimasa Yoshikawa

Hiroo Kanamori
Jun'ichiro Kawaguchi
Takafumi Matsui
Hitoshi Mizutani

Toshitaka Tsuda
Zhongliang Wu
Kiyoshi Yomogida

Advisory Board
Benjamin Fong Chao
Bernard Chouet
Yoshimori Honkura
Toshihiko Iyemori

Journal Scope
Earth, Planets and Space (EPS) is the official journal of the Society of Geomagnetism and Earth, Planetary
and Space Sciences, The Seismological Society of Japan, The Volcanological Society of Japan, The
Geodetic Society of Japan, and The Japanese Society for Planetary Sciences.
EPS is a peer-reviewed, open-access journal published under SpringerOpen. It is an international journal
covering scientific articles in the entire field of earth and planetary sciences, particularly geomagnetism,aeronomy, space science, seismology, volcanology, geodesy, and planetary science. EPS also welcomesarticles in new and interdisciplinary subjects, and technical reports on instrumentation and software.
The journal was launched in 1998 and has since published over 2700 articles. All of them are available forfree on SpringerLink:
http://link.springer.com/journal/40623
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http://earth-planets-space.springeropen.com
Submit your next research article to Earth, Planets and Space via:
https://www.editorialmanager.com/epsp
Yours sincerely,
Prof. Yasuo Ogawa
Editor-in-Chief, Earth, Planets and Space
editor-in-chief@earth-planets-space.org

Earth, Planets and Space
Oda et al. Earth, Planets and Space (2016) 68:59
DOI 10.1186/s40623-016-0437-x

Open Access

PREFACESpecial issue on “Recent advances inenvironmental magnetismand paleomagnetism”
Hirokuni Oda1*, Yuhji Yamamoto2, Xixi Zhao3,4, Satria Bijaksana5 and Qingsong Liu6
Introduction
This special issue is based primarily on Session SE04
“Recent advances in paleo-, rock and environmental
magnetism” held during the Asia Oceania Geosciences
Society (AOGS) 2014 Meeting (28 July–1 August in Sapporo, Japan). The special issue focuses on various topics
in environmental, rock, and paleomagnetism including
applications, instruments, and databases and is not
limited to the presentations at the Session. In total, 13
articles were published in the special issue, which aredescribed below in several categories.

record of core MD05-2928. Rock magnetic analyses
indicate that magnetic minerals were fewer and finer ininterglacial periods, whereas the opposite is the case for
glacial periods. Frequency analyses could resolve Milankovitch cycles. The strongest climate signal is the 100-ka
period, which indicates that sea-level change played adominant role in the long-term environmental setting;additionally, the signals of the 40- and 20-ka periods possibly suggest the influence of regional precipitation.
Kars and Kodama (2015) presented a high-resolution
rock magnetic record from 169 samples collected at Hole
C0008A in the Nankai Trough, offshore southwest Japan,
during Integrated Ocean Drilling Program Expedition
316. The rock magnetic study, conducted at a core depth
from 110 to 153 m below the sea floor, highlighted thewidespread occurrence of magnetic iron sulfides, particularly greigite. Two thick iron sulfide layers containing
greigite and pyrrhotite were identified, which are associated with the occurrence of gas hydrate. It is likely that a
combination of many factors (availability of reactive iron,microbial activity, etc.) favors the formation of ferrimagnetic iron sulfides in the presence of gas hydrates.
Hayashida et al. (2015) presented the magnetic properties of sediment collected from Lake Ogawara to
examine the limnological conditions on the Pacific coastof northeastern Japan shortly after the 2011 Tohoku
earthquake and flooding of the lake by tsunami waves.
At water depths below 10 m, the magnetic susceptibility and anhysteretic remanent magnetization (ARM)of high organic content greenish-black mud decreased
considerably with increasing water depth. ARM
increased slightly at water depths greater than 16 m.
Although it is not clear whether the ARM carriers were
the result of authigenic iron sulfide formation or thedeposition of material suspended in the hypolimnion
water layer, they suggest that the magnetic properties ofthe surficial sediments on the lake floor are controlled

Environmental and rock magnetism: applications
In the special issue, a total of five articles were publishedon various aspects of environmental magnetism. Liuet al. (2015) presented a characterization of iron oxides insurface sediments from potential dust source regions distributed throughout western and northern China. Magnetic mineral assemblages in the studied samples containboth antiferromagnetic (hematite and goethite) and ferrimagnetic (magnetite and maghemite) minerals withbroad grain size distributions indicating multiple origins.
Chinese Loess Plateau (CLP) sediments have relatively
uniform magnetic properties, whereas the source material does not. The results provide excellent constraints on
the initial properties of dust sources that are transported
either to the CLP by the Asian winter monsoon or to theNorth Pacific Ocean by westerly winds.
Huang et al. (2015) presented the environmental magnetic variation around Papua New Guinea for the past
400 ka based on magnetic parameters and the δ18O

*Correspondence: hirokuni‑oda@aist.go.jp
1
Geological Survey of Japan, Research Institute of Geology
and Geoinformation, AIST, Tsukuba, Japan
Full list of author information is available at the end of the article© 2016 Oda et al. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium,provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license,
and indicate if changes were made.

1

Recent Advances in Environmental Magnetism and Paleomagnetism
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Page 2 of 3

archeointensity results. These samples mainly consisted ofTi-poor titanomagnetite grains, approximately 10 nm in
size, with SD and/or SP states. They concluded that baked
clay samples from a kiln floor are considered to be ideal
materials for archeointensity studies.
A frontier letter by Sato et al. (2015) presented the rockmagnetic properties of 1037 single zircon crystals sampled from the Nakagawa River, which crosses the Tanzawa tonalitic pluton in central Japan, for the purpose of
future paleointensity studies. The isothermal remanent
magnetization (IRM) intensities of 161 zircon crystals(>~4 × 10−12 Am), which contained enough magnetic
minerals, could be measured in a DC SQUID magnetometer. In the case that the crystals had low coercivity (Bc)values (<10 mT) and low natural remanent magnetizationto IRM ratios (NRM/IRM) (<~0.1), the main remanence
carriers appear to be nearly stoichiometric magnetite with pseudo-single-domain grain sizes, which are
expected to be appropriate for the paleointensity study.
TRM acquisition experiments on 12 zircon crystals that
fulfilled these criteria show NRM/TRM ratios between 0
and 2, indicating that the NRM intensity is comparablewith that of the TRM. The paleointensity estimated using
the bulk NRM/TRM ratio for a sample with strong TRM
showed a field intensity that was consistent with the geomagnetic field intensity over the last 5 Myr.

by both their location within the basin and the limnological stratification of the brackish lake water.
Oda et al. (2016) presented volcanic ash particles
extracted from tephra-bearing ice samples collected fromthe Nansen Ice Field south of the Sør Rondane Mountains, Antarctica. Major element concentrations of the
volcanic particles show high similarity with those oftephra layers associated with the South Sandwich Islandsin the EPICA-Dome C, Vostok, and Dome Fuji ice cores.
Rock magnetic experiments show that the magnetic
mineral is pseudo-single-domain titanomagnetite, withulvospinel content of 0.2–0.35, mixed with single-domain(SD) to superparamagnetic (SP) (titano)magnetite.
Small blocks of the tephra-bearing ice were magnetizedwith a DC magnetic field of 25 mT and measured usinga SQUID gradiometer, which enabled detection of themagnetic signal including that from samples with imperceptible quantities of tephra particles.

Environmental and rock magnetism: instruments
and software
A frontier letter by Kodama (2015) presented an
improved method for measuring dynamic magnetizations of bulk volcanic rock samples induced by a pulsed
field using inductive differential coils, a preamplifier, integrator, and a high-speed digital storage scope. The measured M–H curves are comparable to the branches of thecorresponding hysteresis loops measured in a static field.
The pulse provides the rapid exponential decay with time
constant corresponding to magnetic relaxation time. The
system has the potential to be a versatile and convenient
tool for rock magnetism.
A technical report by Fukuma and Kono (2016) presented a LabVIEW software program to control an
automated three-component spinner magnetometerequipped with a thermal demagnetizer TSpin, which isutilized for routine operations in Thellier paleointensity
experiments, enabling an overnight Thellier measurement without any user intervention. Due to a continuous
series of remanence measurements combined with thermal demagnetization or partial thermoremanent magnetization (TRM) acquisition in a magnetic shield casewithout manual handling of a specimen, the chance of anorientation error or acquisition of spurious magnetization is almost completely eliminated.

Paleomagnetism: tectonics
There are two articles in the special issue dealing withtectonics in East Asia. Based on a paleomagnetic studyon Miocene sediments from the Oidawara Formation,eastern southwest Japan, Hoshi et al. (2015) revealed
that clockwise rotation of southwest Japan occurred
mainly between 17.5 and 15.8 Ma, at a rotation rate of~23°/Myr. Furthermore, Jeong et al. (2015) presented
the tectonic evolution of the Korean Peninsula basedon the paleomagnetism and U–Pb geochronology of thelate Cretaceous Chisulryoung Volcanic Formation. The
weighted mean ages obtained by U–Pb zircon datingfrom the base and top of the formation are 72.8 ± 1.7 and67.7 ± 2.1 Ma, respectively. Paleomagnetic results fromthe late Cretaceous ignimbrites show that Korea has been
rigidly attached to China at least since the Cretaceous.
Paleomagnetism: database
Two technical reports on the paleomagnetic database
GEOMAGIA50.v3 published in this special issue play animportant role in paleomagnetism. Brown et al. (2015a)
presented the development of a database dealing withpaleomagnetic data for archeological and volcanic materials, which contains 14,645 data (declination, inclination, and paleointensity) from 461 studies publishedbetween 1959 and 2014. The web-based interface can be

Paleomagnetism: paleointensity
Two articles in the special issue are related to paleointensity studies. Yamamoto et al. (2015) presented anarcheointensity study on baked clay samples taken from areconstructed ancient kiln. Application of the Tsunakawa–
Shaw method to the samples showed that those obtained
from the floor surface of the kiln provided accurate2Earth, Planets and Space
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Page 3 of 3

found at http://geomagia.gfz-potsdam.de. In addition,
Brown et al. (2015b) presented a new database for sediments built upon the above-mentioned GEOMAGIA50.
v3. For sediments, a strong emphasis has been placed on
the storage of geochronological data, and this is the firstmagnetic archive that includes comprehensive radiocarbon age data from sediments. The web-based interface
for the sediment database is located at http://geomagia.
gfz-potsdam.de/geomagiav3/SDquery.php. The databasecontinues to expand as legacy data are added and newstudies are published.

Fukuma K, Kono M (2016) A LabVIEW software for Thellier paleointensity meas‑
urements with an automated three‑component spinner magnetometer
TSpin. Earth Planets Space 68:43. doi:10.1186/s40623‑016‑0424‑2
Hayashida A, Nakano R, Nagashima A, Seto K, Yamada K, Yonenobu H (2015)
Magnetic properties of surficial sediments in Lake Ogawara on the
Pacific coast of northeastern Japan: spatial variability and correlation withbrackish water stratification. Earth Planets Space 67:171. doi:10.1186/
s40623‑015‑0343‑7
Hoshi H, Kato D, Ando Y, Nakashima K (2015) Timing of clockwise rotation ofSouthwest Japan: constraints from new middle Miocene paleomagnetic
results. Earth Planets Space 67:92. doi:10.1186/s40623‑015‑0266‑3
Huang YS, Lee TQ, Hsu SK (2015) Orbital‑scale variation in the magnetic con‑tent as a result of sea level changes in Papua New Guinea over the past
400 ka. Earth Planets Space 67:128. doi:10.1186/s40623‑015‑0294‑z
Jeong D, Yu Y, Doh SJ, Suk D, Kim J (2015) Paleomagnetism and U–Pb geochro‑nology of the late Cretaceous Chisulryoung Volcanic Formation, Korea:
tectonic evolution of the Korean Peninsula. Earth Planets Space 67:66.
doi:10.1186/s40623‑015‑0242‑yKars M, Kodama K (2015) Rock magnetic characterization of ferrimagnetic
iron sulfides in gas hydrate‑bearing marine sediments at Site C0008,
Nankai Trough, Pacific Ocean, off‑coast Japan. Earth Planets Space 67:118.
doi:10.1186/s40623‑015‑0287‑yKodama K (2015) Pulsed‑field magnetometry for rock magnetism. Earth Plan‑
ets Space 67:122. doi:10.1186/s40623‑015‑0294‑z
Liu Q, Sun Y, Qiang X, Tada R, Hu P, Duan Z, Jiang Z, Liu J, Su K (2015) Character‑izing magnetic mineral assemblages of surface sediments from major
Asian dust sources and implications for the Chinese loess magnetism.
Earth Planets Space 67:61. doi:10.1186/s40623‑015‑0237‑8
Oda H, Miyagi I, Kawai J, Suganuma Y, Funaki M, Imae N, Mikouchi T, Matsuzaki
T, Yamamoto Y (2016) Volcanic ash in bare ice south of Sør Rondane
Mountains, Antarctica: geochemistry, rock magnetism and nondestruc‑tive magnetic detection with SQUID gradiometer. Earth Planets Space
68:39. doi:10.1186/s40623‑016‑0415‑3
Sato M, Yamamoto S, Yamamoto Y, Okada Y, Ohno M, Tsunakawa H, Maruyama
S (2015) Rock‑magnetic properties of single zircon crystals sampled fromthe Tanzawa tonalitic pluton, central Japan. Earth Planets Space 67:150.
doi:10.1186/s40623‑015‑0317‑9
Yamamoto Y, Torii M, Natsuhara N (2015) Archeointensity study on baked clay
samples taken from the reconstructed ancient kiln: implication for valid‑
ity of the Tsunakawa–Shaw paleointensity method. Earth Planets Space
67:63. doi:10.1186/s40623‑015‑0229‑8

Abbreviations
ARM: anhysteretic remanent magnetization; CLP: Chinese Loess Plateau;
IRM: isothermal remanent magnetization; NRM: natural remanent magneti‑zation; SD: single‑domain; SP: superparamagnetic; TRM: thermoremanent
magnetization.
Author details
1
Geological Survey of Japan, Research Institute of Geology and Geoinforma‑tion, AIST, Tsukuba, Japan. 2 Center for Advanced Marine Core Research, Kochi
University, Kochi, Japan. 3 University of California Santa Cruz, Santa Cruz, CA,
USA. 4 School of Ocean and Earth Science, Tongji University, Shanghai, China.
5Institut Teknologi Bandung, Bandung, Indonesia. 6 State Key Laboratoryof Lithospheric Evolution, Institute of Geology and Geophysics, Chinese Acad‑emy of Sciences, Beijing, China.
Acknowledgements
We are very grateful to the authors who submitted papers to this special
issue and the many referees who have given their time and provided us withvaluable suggestions. We would like to express our gratitude to the organizersof the AOGS 2014 Meeting in Sapporo. Session SE04 was convened by Yuhji
Yamamoto, Hirokuni Oda, Andrew P. Roberts, Xixi Zhao, and Satria Bijaksana.
Our special thanks go to Kazuto Kodama who initiated the session.
Received: 5 April 2016 Accepted: 5 April 2016

References
Brown MC, Donadini F, Korte M, Nilsson A, Korhonen K, Lodge A, Lengyel SN,
Constable CG (2015a) GEOMAGIA50.v3: 1. general structure and modifi‑
cations to the archeological and volcanic database. Earth Planets Space
67:83. doi:10.1186/s40623‑015‑0232‑0
Brown MC, Donadini F, Nilsson A, Panovska S, Frank U, Korhonen K, SchuberthM, Korte M, Constable CG (2015b) GEOMAGIA50.v3: 2. A new paleomag‑
netic database for lake and marine sediments. Earth Planets Space 67:70.
doi:10.1186/s40623‑015‑0233‑z3

Recent Advances in Environmental Magnetism and Paleomagnetism

FRONTIER LETTER Open Access

Pulsed-field magnetometry for rock magnetism
Kazuto Kodama
Earth, Planets and Space 2015, 67:122 DOI: 10.1186/s40623-015-0294-z
Received: 30 March 2015, Accepted: 15 July 2015, Published: 31 July 2015

Abstract
An improved method is proposed for measuring dynamic magnetizations of bulk volcanic rock samples induced by a pulsedfield of 0.7 T and a duration of 10 ms. The transient magnetization is measured by a sensing system that consists of a pair of
inductive differential coils, an analog preamplifier and integrator, and a high-speed digital storage scope. The system wascalibrated using a paramagnetic salt (Gd2O3) and was tested to different kinds of volcanic rocks with their magnetic properties
well-documented previously. The results were comparable with those measured by a quasi-static method using a vibrating
sample magnetometer, although there were small discrepancies in hysteresis parameters suggesting the time-dependence ofthe magnetic properties. The proposed system provides not only the magnetization over the short interval of a pulse but also
the rapid (~3 ms) exponential decay after a pulse. The decay time constant was different among the samples under study,
indicating the variations of their magnetic relaxation time. Although the present system is not sensitive enough tocharacterize varieties of natural samples including sediments, it has thepotential as a versatile and convenient tool for rock magnetism.

Keywords: Rock magnetism; Pulsed-field; Magnetometry; Dynamic
magnetization; Hysteresis

Figure 1

Corresponding author: Kazuto Kodama, kdma@kochi-u.ac.jp

FRONTIER LETTER Open Access

Rock-magnetic properties of single zircon crystals sampledfrom the Tanzawa tonalitic pluton, central Japan
Masahiko Sato*, Shinji Yamamoto, Yuhji Yamamoto, Yoshihiro Okada, Masao Ohno,
Hideo Tsunakawa and Shigenori Maruyama
Earth, Planets and Space 2015, 67:150 DOI: 10.1186/s40623-015-0317-9
Received: 11 May 2015, Accepted: 27 August 2015, Published: 15 September 2015

Abstract
This paper reports on the rock-magnetic properties of single zircon crystals, which are essential for future work establishing the reliablepaleointensity method using single zircon crystals. Zircon crystals used in this study were sampled from the Nakagawa River, which crosses
the Tanzawa tonalitic pluton in central Japan. Rock-magnetic measurements were conducted on 1037 grains of zircons, but many of thesemeasurements are below the limits of the sensitivity of the magnetometers employed. Isothermal remanent magnetizations (IRMs) of 876
zircon crystal are below the practical resolution of this study; we infer that these crystals contain no or only minute quantities offerromagnetic minerals. The other zircon crystals contain enough magnetic minerals to be measured in the DC SQUID magnetometer. For 81
zircon crystals, IRM intensities (MIRM) are larger than 4 × 10−12 Am2, while natural remanent magnetization (NRM) intensities (MNRM) are below
4 × 10−12 Am2, indicating that these crystals are inappropriate for the paleomagnetic study. For the samples that had values of MNRM ≥ 4 × 10−12
Am2 and MIRM ≥ 4 × 10−12 Am2 (80 zircons), combining the rock-magnetic parameter, we proposed the sample-selection criteria for future studyof paleointensity experiments using single zircon crystals. In the case that the samples had highcoercivity (Bc) values (>10 mT) or high MNRM/MIRM values (>~0.1), main remanence carriers areprobably pyrrhotite and these samples are inappropriate for the paleointensity study. In thecase that the samples had low Bc values (<10 mT) and low MNRM/MIRM values (<~0.1), main
remanence carriers seem to be nearly pure magnetite with pseudo-single-domain grain sizes,
and these samples are expected to appropriate for the paleointensity study. Total
thermoremanent magnetization (TRM) acquisition experiments were also carried out for 12
samples satisfying the above criteria. The TRM intensity was comparable with that of NRM, anda rough estimation of the paleointensity using NRM/TRM ratios shows field intensities
consistent with the average geomagnetic field intensity at the Tanzawa tonalitic pluton for last
5 Myr.

Keywords: Rock-magnetism; Paleointensity; Zircon; Tanzawa tonalitic pluton*Corresponding author: Masahiko Sato, m.satou@aist.go.jp
4

Figure 1

Earth, Planets and Space

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Open Access

Characterizing magnetic mineral assemblages of surface sedimentsfrom major Asian dust sources and implications for the Chinese loessmagnetism
Qingsong Liu*, Youbin Sun, Xiaoke Qiang, Ryuji Tada, Pengxiang Hu, Zongqi Duan, Zhaoxia Jiang,
Jianxing Liu and Kai Su
Earth, Planets and Space 2015, 67:61 DOI: 10.1186/s40623-015-0237-8
Received: 27 January 2015, Accepted: 20 April 2015, Published: 8 May 2015

Abstract
Eolian dust plays an important role in the Earth’s climate system. Environmental magnetism has been widely used to trace dust variations at
different spatial and temporal scales. However, the magnetic properties of sediments from key dust sources have not been well determined.
In this study, surface samples from potential dust sources in inner Eastern Asia were systematically investigated. Our results indicate thatferrimagnetic and antiferromagnetic minerals are both present in surface sediments and that they have broad grain size distributions.
Ferrimagnetic components are dominated by partially oxidized coarse-grained (pseudo-single domain and multi-domain) lithogenic
magnetite particles with minor contributions from pedogenic fine-grained (single domain and superparamagnetic) particles.
Antiferromagnetic hematite can be classified into three groups in terms of diffuse reflectance spectroscopy (DRS) band positions (P560 nm, P545 nm,
and P535 nm, where numbers indicate the DRS band wavelength for hematite). The first group (P560 nm) is the coarse-grained hematite oflithogenic origin and is mostly confined to western China. The P535 nm group is of
pedogenic origin. The P545 nm group is an intermediate phase that is present both insurface samples from the source regions and in loess. Therefore, the P545 nm and P535 nm
groups are related to eolian inputs to the Chinese Loess Plateau and pedogenic
processes, respectively. In addition, significant differences exist between the magnetic
properties of eolian material from sources and depositional regions due togravitational sorting. These insights provide strong constraints on interpretation ofdust signals recorded by the Chinese loess and marine sediments from the North
Pacific Ocean.

Keywords: Eolian dust; Environmental magnetism; Hematite; Diffuse reflectancespectroscopy; Eastern Inland Asia; Chinese loess

Figure 1*Corresponding author: Qingsong Liu, qsliu@mail.iggcas.ac.cn

FULL PAPER

Open AccessArcheointensity study on baked clay samples taken from thereconstructed ancient kiln: implication for validity of the
Tsunakawa-Shaw paleointensity method
Yuhji Yamamoto*, Masayuki Torii and Nobuyoshi Natsuhara
Earth, Planets and Space 2015, 67:63 DOI: 10.1186/s40623-015-0229-8
Received: 16 January 2015, Accepted: 14 April 2015, Published: 8 May 2015

Abstract
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 thepaleomagnetic directions by partial alternating field demagnetizations. We recently applied the Tsunakawa-Shaw method to thesamples to assess how reliable archeointensity results are obtained from the samples. A suite of the rock magnetic experiments andthe 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 ofmulti-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 anarcheointensity 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 theunblocking temperature spectra of the samples, the floor surface samples acquired fullthermoremanent 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.

Keywords: Archeointensity; Absolute paleointensity; Baked clay; Kiln; Tsunakawa-Shaw
method*Corresponding author: Yuhji Yamamoto, y.yamamoto@kochi-u.ac.jp
5Figure 1

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Open Access

Paleomagnetism and U-Pb geochronology of the late
Cretaceous Chisulryoung Volcanic Formation, Korea:
tectonic evolution of the Korean Peninsula
Doohee Jeong, Yongjae Yu*, Seong-Jae Doh, Dongwoo Suk and Jeongmin Kim
Earth, Planets and Space 2015, 67:66 DOI: 10.1186/s40623-015-0242-y
Received: 27 November 2014, Accepted: 23 April 2015, Published: 8 May 2015

Abstract
Late Cretaceous Chisulryoung Volcanic Formation (CVF) in southeastern Korea contains four
ash-flow ignimbrite units (A1, A2, A3, and A4) and three intervening volcano-sedimentarylayers (S1, S2, and S3). Reliable U-Pb ages obtained for zircons from the base and top of the
CVF were 72.8 ± 1.7 Ma and 67.7 ± 2.1 Ma, respectively. Paleomagnetic analysis on pyroclastic
units yielded mean magnetic directions and virtual geomagnetic poles (VGPs) as D/I =
19.1°/49.2° (α95 = 4.2°, k = 76.5) and VGP = 73.1°N/232.1°E (A95 = 3.7°, N = 3) for A1, D/I =
24.9°/52.9° (α95 = 5.9°, k = 61.7) and VGP = 69.4°N/217.3°E (A95 = 5.6°, N = 11) for A3, and D/I =
10.9°/50.1° (α95 = 5.6°, k = 38.6) and VGP = 79.8°N/242.4°E (A95 = 5.0°, N = 18) for A4. Our best
estimates of the paleopoles for A1, A3, and A4 are in remarkable agreement with thereference apparent polar wander path of China in late Cretaceous to early Paleogene,confirming that Korea has been rigidly attached to China (by implication to Eurasia) at least
since the Cretaceous. The compiled paleomagnetic data of the Korean Peninsula suggestthat the mode of clockwise rotations weakened since the mid-Jurassic. Such interesting
variation of vertical rotations in the Korean Peninsula might result from the strike-slip
motions of major faults developed in East Asia (the Tancheng-Lujiang fault to the northwest
and the Korea-Taiwan strait fault to the southeast), near-field tectonic forcing of the
subducting Pacific Plate beneath the Eurasian Plate, and far-field expressions of the IndiaAsia collision.

Figure 1*Corresponding author: Yongjae Yu, yongjaeyu@cnu.ac.kr

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Open Access

Timing of clockwise rotation of Southwest Japan:
constraints from new middle Miocene paleomagnetic results
Hiroyuki Hoshi*, Daiki Kato, Yoshikazu Ando and Kazuo Nakashima
Earth, Planets and Space 2015, 67:92 DOI: 10.1186/s40623-015-0266-3
Received: 13 February 2015, Accepted: 8 June 2015, Published: 19 June 2015

Abstract
Southwest Japan rotated clockwise during the late stage of the opening of the Japan Sea, although the exact timing of therotation is controversial. A recent biostratigraphic study has revealed that the Miocene Oidawara Formation in easternSouthwest Japan was deposited just before 15 Ma; consequently, its paleomagnetic direction may help constrain the timingof rotation. For this purpose, we collected fine felsic tuffs and siltstones at 71 stratigraphic sites (horizons) in the Oidawara
Formation. An analysis of alternating field and thermal demagnetization results yielded characteristic remanent
magnetization (ChRM) directions for 177 samples. Approximately 80 % (142) of the samples exhibit reverse polarity ChRM
directions that are thought to be paleofield directions of reverse polarity Chron C5Br. Normal polarity ChRM directions in 35
samples include primary paleofield records as well as records of secondary
magnetization. The data suggest that a short normal polarity interval (microchronor cryptochron) at ~15.8 Ma is present within the dominantly reverse polarity
interval of Chron C5Br. Reliable site-mean directions for 19 sites yield a tiltcorrected formation-mean direction of D = 10.5°, I = 41.1°, α95 = 7.0°, and k = 23.9,
indicating virtually no rotation with respect to a reference paleomagnetic direction
for the Asian continent. A rotation versus age plot for Southwest Japan indicatesthat the clockwise rotation started after 17.5 Ma and ceased largely before 15.8 Ma,
yielding a rotation rate of ~23°/Myr.

Keywords: Magnetostratigraphy; Miocene; Mizunami Group; Oidawara Formation;
Paleomagnetism; Rock magnetism; Southwest Japan; Tectonic rotation

Figure 1*Corresponding author: Hiroyuki Hoshi, hoshi@auecc.aichi-edu.ac.jp
6Earth, Planets and Space

FULL PAPER

Open Access

Rock magnetic characterization of ferrimagnetic iron sulfides in gas
hydrate-bearing marine sediments at Site C0008, Nankai
Trough, Pacific Ocean, off-coast Japan
Myriam Kars* and Kazuto Kodama
Earth, Planets and Space 2015, 67:118 DOI: 10.1186/s40623-015-0287-y
Received: 27 February 2015, Accepted: 30 June 2015, Published: 29 July 2015

Abstract
A high-resolution rock magnetic study was carried out in Integrated Ocean Drilling Program (IODP) Expedition 316 Hole
C0008A located in the Megasplay Fault Zone of the Nankai Trough, SW offshore Japan, in order to document changes inmagnetic properties throughout gas hydrate-bearing horizons. A total of 169 Pleistocene
discrete samples were collected from ~110 to 153 m core depth below sea floor (CSF),
and their magnetic minerals concentration, grain size, composition, and rock magnetic
parameters were estimated. Results showed the presence of iron oxides ((titano)magnetite), iron sulfides (greigite and pyrrhotite), and their mixture, among which
single-domain greigite is the most major magnetic mineral present in the samples. Twohorizons containing ferrimagnetic iron sulfides (114.5–127.5 and 129.5–150 m CSF)
covering almost the entire studied interval were identified, both associated with slight
local pore water anomalies, suggesting occurrence of gas hydrates and anoxic conditions.
These results are different from the neighboring Hole C0008C (215 m away from Hole
C0008A) where four pore water anomalies and six iron sulfide-rich intervals wereidentified for the same time slice. Comparison of the lithology, physical properties, andgeochemical data of the two boreholes at Site C0008 suggests that a combination ofprocesses (e.g., availability of reactive iron, microbial activity) is responsible for suchlaterally varying distribution of the ferrimagnetic iron sulfides.

Keywords: Iron sulfides; Greigite; Pyrrhotite; Gas hydrate; C0008; IODP Expedition 316;
Nankai TroughFigure 1*Corresponding author: Myriam Kars, jm-mkars@kochi-u.ac.jp

FULL PAPER

Open Access

Orbital-scale variation in the magnetic content as a result ofsea level changes in Papua New Guinea over the past 400 ka
Yin-Sheng Huang*, Teh-Quei Lee and Shu-Kun Hsu
Earth, Planets and Space 2015, 67:128 DOI: 10.1186/s40623-015-0300-5
Received: 30 January 2015, Accepted: 3 August 2015, Published: 14 August 2015

Abstract
We describe the orbital-scale environmental variation around Papua New Guinea (PNG) for the last 400 ka based on theenvironmental magnetism. Six magnetic parameters and the δ18O record of the core MD05-2928 are presented in the study.
Results of magnetic analyses reveal opposite responses to different environmental conditions: Magnetic minerals wererelatively fewer and finer in interglacial periods and were more and coarser in glacial periods. The reason could be suggested:
In interglacial periods, sediments coming from central New Guinea were transported by the coastal currents in the northern
Coral Sea and then imported to the core site location. Magnetic minerals would be relatively fewer and finer due to this longer
transportation process. In glacial periods, the routes of the currents might regressseaward with reduced current intensity because of lower sea level. Main sedimentsources would shift to the Papuan Peninsula relatively near the core site, andtherefore, the magnetic minerals became more and coarser. Further, period analyses
using the eccentricity, tilt, and precession (ETP) curves and the wavelet spectra wereapplied to the study to analyze the periodicities embedded in the parameters.
Results of both period analyses clearly present the Milankovitch periods, indicating
the dominance of the orbital forcing in this area. The strongest signal of 100-ka
period reveals that sea level change played the dominant role in long-term
environmental setting for the past ~400 ka. However, influences of 40- and 20-ka
periods, possibly related to regional precipitation, should also be considered though
they might be second factors affecting the environmental variation around PNG.

Keywords: Papua New Guinea; Coral Sea; Wavelet analysis; Orbital forcing;
Milankovitch cycles*Corresponding author: Yin-Sheng Huang, yinson@earth.sinica.edu.tw
7

Figure 1

Recent Advances in Environmental Magnetism and Paleomagnetism

FULL PAPER

Open Access

Magnetic properties of surficial sediments in Lake Ogawara on the
Pacific coast of northeastern Japan: spatial variability andcorrelation with brackish water stratification
Akira Hayashida*, Ryoma Nakano, Aya Nagashima, Koji Seto, Kazuyoshi Yamada and Hitoshi Yonenobu
Earth, Planets and Space 2015, 67:171 DOI: 10.1186/s40623-015-0343-7
Received: 31 January 2015, Accepted: 14 October 2015, Published: 23 October 2015

Abstract
To examine limnological conditions in Lake Ogawara on the Pacific coast of northwestern Japan, we investigated the magnetic
properties of dredged bottom sediment originally collected from the lake in the summer of 2011. We used non-destructive
methods to measure the low-field magnetic susceptibility shortly after sampling, andanhysteretic remanent magnetization (ARM) was assessed in 2012 and 2015. The ARM acquisitionand demagnetization curves from littoral sites showed several patterns that reflect theprovenance of the sediments. At water depths below 10 m, the magnetic susceptibility and ARMof greenish black mud with high organic content decreased considerably with the increase inwater depth, but ARM increased slightly at water depths greater than 16 m. We also found thatthe magnetic concentrations of mud samples were reduced markedly during a period of storage
for about 3 years. We attributed these reductions to diagenetic loss of magnetic minerals, which
had been enhanced at deeper sites. It is possible that the ARM carriers in deeper areas were
derived from authigenic formation of iron sulfide or from deposition of suspended matter in thehypolimnion water. We propose that the magnetic properties of surficial sediments arecontrolled by limnological stratification of the brackish lake water, thus possibly providing ananalog for down-core variations of magnetic parameters associated with the modification ofmagnetic minerals during reductive diagenesis.

Keywords: Environmental magnetism; Lake sediment; Magnetic properties; Reductive
diagenesis; Storage diagenesis

Figure 1*Corresponding author: Akira Hayashida, ahay@mail.doshisha.ac.jp

FULL PAPER

Open Access

Volcanic ash in bare ice south of Sør Rondane Mountains, Antarctica:
geochemistry, rock magnetism and nondestructive magnetic detection
with SQUID gradiometer
Hirokuni Oda*, Isoji Miyagi, Jun Kawai, Yusuke Suganuma, Minoru Funaki, Naoya Imae,
Takashi Mikouchi, Takuya Matsuzaki and Yuhji Yamamoto
Earth, Planets and Space 2016, 68:39 DOI: 10.1186/s40623-016-0415-3
Received: 30 July 2015, Accepted: 17 February 2016, Published: 9 March 2016

Abstract
Nondestructive magnetic detection of tephra layers in ice cores will be an important method to identify and correlate stratigraphic
horizons of ice bearing volcanic ash particles. Volcanic ash particles were extracted from tephra-bearing ice samples collected from
Nansen Ice Field south of the Sør Rondane Mountains, Antarctica. Particles are fresh glassy volcanic ash with diameters of ~50 μm,
and chemical composition of the matrix glass belongs to a low-K basaltic andesite group, ranging from SiO2 60–62 wt% and K2O
0.40–0.50 wt%. Considering the grain size of ash particles and chemical composition of volcanic glass, the ash in tephra-bearing ice
samples might be originated from the South Sandwich Islands located 2800 km northwest of the sampling sites. Correlations on
major element concentrations with tephra layers associated with South Sandwich Islands in EPICAa
Dome C, Vostok, and Dome Fuji ice cores show high similarity. Rock magnetic experiments showthat the magnetic mineral is pseudo-single-domain titanomagnetite with ulvospinel content of
0.2–0.35 mixed with single-domain to superparamagnetic (titano)magnetite. Small blocks of theatephra-bering ice were measured with a SQUID gradiometer at 1-mm intervals with a spatial
resolution of ~3 mm. With DC magnetic field of 25 mT, magnetic signal could be enhanced anddetected for all the samples including the one with invisible amount of tephra particles. In order tosimulate a thin ash layer in ice core, volcanic ash particles extracted from the tephra-bearing ice
were used to fabricate a thin ash layer, which were subsequently magnetized, measured with thegradiometer. The noise level for Z axis gradiometer was about 0.6 pT. Detection limit for a halfcylinder with 29 mm radius and a thickness of 1 mm uniformly magnetized in X axis direction is~9 × 10−5 A/m, which could be improved down to ~2 × 10−6 A/m by reducing the sensor-to-sample
distance to 0.5 mm.
Figure 1*Corresponding author: Hirokuni Oda, hirokuni-oda@aist.go.jp
8Earth, Planets and SpaceTECHNICAL REPORT

Open Access

GEOMAGIA50.v3: 1. General structure and modifications to thearcheological and volcanic database
Maxwell C Brown*, Fabio Donadini, Monika Korte, Andreas Nilsson, Kimmo Korhonen,
Alexandra Lodge, Stacey N Lengyel and Catherine G Constable
Earth, Planets and Space 2015, 67:83 DOI: 10.1186/s40623-015-0232-0
Received: 4 February 2015, Accepted: 17 April 2015, Published: 12 May 2015

Abstract
Background: GEOMAGIA50.v3 is a comprehensive online database providing access to published paleomagnetic, rock magnetic, andchronological data from a variety of materials that record Earth’s magnetic field over the past 50 ka.
Findings: Since its original release in 2006, the structure and function of the database have been updated and a significant number of data havebeen added. Notable modifications are the following: (1) the inclusion of additional intensity, directional and metadata from archeological andvolcanic materials and an improved documentation of radiocarbon dates; (2) a new data model to accommodate paleomagnetic, rock magnetic,
and chronological data from lake and marine sediments; (3) a refinement of the geographic constraints in the archeomagnetic/volcanic queryallowing selection of particular locations; (4) more flexible methodological and statistical constraints in the archeomagnetic/volcanic query; (5)the calculation of predictions of the Holocene geomagnetic field from a series of time varying global field models; (6) searchable reference lists;and (7) an updated web interface. This paper describes general modifications to the database andspecific aspects of the archeomagnetic and volcanic database. The reader is referred to a25
companion publication for a description of the sediment database.
20
NumberConclusions: The archeomagnetic and volcanic part of GEOMAGIA50.v3 currently contains 14,645
data (declination, inclination, and paleointensity) from 461 studies published between 1959 and2014. We review the paleomagnetic methods used to obtain these data and discuss applications of
the data within the database. The database continues to expand as legacy data are added and newstudies published. The web-based interface can be found at http://geomagia.gfz-potsdam.de.

15
10
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Keywords: Geomagnetism; Paleomagnetism; Archeomagnetism; Database; GEOMAGIA50

1960

1970

1980

1990

2000

2010

Publication Year

Figure 1*Corresponding author: Maxwell C Brown, mcbrown@gfz-potsdam.de

TECHNICAL REPORT

Open Access

GEOMAGIA50.v3: 2. A new paleomagnetic database for lake andmarine sediments
Maxwell C Brown*, Fabio Donadini, Andreas Nilsson, Sanja Panovska, Ute Frank, Kimmo Korhonen,
Maximilian Schuberth, Monika Korte and Catherine G Constable
Earth, Planets and Space 2015, 67:70 DOI: 10.1186/s40623-015-0233-z
Received: 4 February 2015, Accepted: 17 April 2015, Published: 12 May 2015

Abstract
Background: GEOMAGIA50.v3 for sediments is a comprehensive online database providing access to publishedpaleomagnetic, rock magnetic, and chronological data obtained from lake and marine sediments deposited over the past 50
ka. Its objective is to catalogue data that will improve our understanding of changes in the geomagnetic field, physicalenvironments, and climate.

Conclusions: The web-based interface for the sediment database is located at
http: //geomagia.gfz-potsdam.de/geomagiav3/SDquery.php. This paper is acompanion to Brown et al. (Earth Planets Space doi:10.1186/s40623-015-0232-0, 2015)
and describes the data types, structure, and functionality of the sediment database.

1012
1010
10

PSD nT2 years

Findings: GEOMAGIA50.v3 for sediments builds upon the structure of the pre-existing
GEOMAGIA50 database for magnetic data from archeological and volcanic materials. A
strong emphasis has been placed on the storage of geochronological data, and it is thefirst magnetic archive that includes comprehensive radiocarbon age data fromsediments. The database will be updated as new sediment data become available.

10

Environmental magnetism; Database; GEOMAGIA50*Corresponding author: Maxwell C Brown, mcbrown@gfz-potsdam.de
9

6

10

4

10
10

2

PADM2MCALS10k.1b
pfm9k.1a
CALS3k.1
ARCH3k.1
gufm1

0

10-2
10

Keywords: Geomagnetism; Paleomagnetism; Sediment magnetism; Rock magnetism;

8

-4

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10

1

2

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Frequency My

Figure 1

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Recent Advances in Environmental Magnetism and Paleomagnetism

TECHNICAL REPORT

Open Access

A LabVIEW software for Thellier paleointensity measurements with
an automated three-component spinner magnetometer TSpin
Koji Fukuma* and Masaru Kono
Earth, Planets and Space 2016, 68:43 DOI: 10.1186/s40623-016-0424-2
Received: 13 September 2015, Accepted: 3 March 2016, Published: 16 March 2016

Abstract
The Thellier method is classical but is still regarded as the most reliable method for paleointensity determination. Recently,
many types of additional protocols have been advocated to ensure reliability and make laboratory work more laborious andtime-consuming. An automated system coupling a magnetometer and an electric furnace is now of prime importance to copewith the increasing demand. Here, we describe a graphics-based program for controlling a fully automatic system combininga spinner magnetometer and a thermal demagnetizer, and for acquiring and processing the magnetization data. A single
fluxgate sensor, which can measure the vector magnetization by spinning and translating a standard-sized 1-in. specimen,
was calibrated with a rotatable reference specimen that can make the magnetization parallel or perpendicular to the spinningaxis. By placing a cooling chamber between the furnace and the sensor for the updated system, the specimen can be heatedup more efficiently to ensure an identical thermal history for the double heatings of the Thellier method. The direction of thevector magnetization was precisely obtained as well as the intensity, the results being comparable with those from an
ordinary spinner magnetometer. We present an application of the fully automatic system for a Thellier measurement on a
recent lava flow, which took about 24 h for approximately
ten-step double heatings without manual operation.

Keywords: Paleointensity; Thellier method; Magnetometer

Figure 1*Corresponding author: Koji Fukuma, kfukuma@mail.doshisha.ac.jp

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Contents
Special issue on “Recent advances in environmental magnetism and paleomagnetism”. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hirokuni Oda, Yuhji Yamamoto, Xixi Zhao, Satria Bijaksana and Qingsong Liu
Pulsed-field magnetometry for rock magnetism. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Kazuto Kodama
Rock-magnetic properties of single zircon crystals sampled from the Tanzawa tonalitic pluton, central Japan. . . . Masahiko Sato, Shinji Yamamoto, Yuhji Yamamoto, Yoshihiro Okada, Masao Ohno, Hideo Tsunakawa and Shigenori Maruyama
Characterizing magnetic mineral assemblages of surface sediments from major Asian dust sources and implications
for the Chinese loess magnetism. . . . . . . . . . . . . Qingsong Liu, Youbin Sun, Xiaoke Qiang, Ryuji Tada, Pengxiang Hu, Zongqi Duan,
Zhaoxia Jiang, Jianxing Liu and Kai Su

Archeointensity study on baked clay samples taken from the reconstructed ancient kiln: implication for validity of the
Tsunakawa-Shaw paleointensity method. . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yuhji Yamamoto, Masayuki Torii and Nobuyoshi Natsuhara
Paleomagnetism and U-Pb geochronology of the late Cretaceous Chisulryoung Volcanic Formation, Korea: tectonic
evolution of the Korean Peninsula. . . . . . . . . . . . . . . . Doohee Jeong, Yongjae Yu, Seong-Jae Doh, Dongwoo Suk and Jeongmin Kim
Timing of clockwise rotation of Southwest Japan: constraints from new middle Miocene paleomagnetic results. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hiroyuki Hoshi, Daiki Kato, Yoshikazu Ando and Kazuo Nakashima
Rock magnetic characterization of ferrimagnetic iron sulfides in gas hydrate-bearing marine sediments at Site C0008,
Nankai Trough, Pacific Ocean, off-coast Japan. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Myriam Kars and Kazuto Kodama
Orbital-scale variation in the magnetic content as a result of sea level changes in Papua New Guinea over the past 400 ka. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yin-Sheng Huang, Teh-Quei Lee and Shu-Kun Hsu
Magnetic properties of surficial sediments in Lake Ogawara on the Pacific coast of northeastern Japan: spatial variability
and correlation with brackish water stratification. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Akira Hayashida, Ryoma Nakano, Aya Nagashima, Koji Seto, Kazuyoshi Yamada and Hitoshi Yonenobu
Volcanic ash in bare ice south of Sør Rondane Mountains, Antarctica: geochemistry, rock magnetism and nondestructive
magnetic detection with SQUID gradiometer. . . . . . . . . . . Hirokuni Oda, Isoji Miyagi, Jun Kawai, Yusuke Suganuma, Minoru Funaki,
Naoya Imae, Takashi Mikouchi, Takuya Matsuzaki and Yuhji Yamamoto

GEOMAGIA50.v3: 1. General structure and modifications to the archeological and volcanic database. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maxwell C Brown, Fabio Donadini, Monika Korte, Andreas Nilsson, Kimmo Korhonen,
Alexandra Lodge, Stacey N Lengyel and Catherine G Constable

GEOMAGIA50.v3: 2. A new paleomagnetic database for lake and marine sediments. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Maxwell C Brown, Fabio Donadini, Andreas Nilsson, Sanja Panovska, Ute Frank, Kimmo Korhonen,
Maximilian Schuberth, Monika Korte and Catherine G Constable

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A LabVIEW software for Thellier paleointensity measurements with an automated three-component spinner magnetometer
TSpin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Koji Fukuma and Masaru Kono 10

Cover image: Sato, M. et al., Earth, Planets and Space 2015, 67:150 DOI: 10.1186/s40623-015-0317-9