Article
Geochemistry & Geophysics
H. Asefaw, L. Tauxe, A. A. P. Koppers, H. Staudigel
Summary: The fundamental assumption in paleomagnetism is that the Earth's magnetic field can be approximated by a geocentric axial dipole (GAD). While global paleomagnetic directions from the last 5 million years support a GAD field structure, paleointensity estimates over the same period do not. This study reexamines the paleomagnetic field structure in Antarctica to determine the validity of low intensity readings.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Multidisciplinary Sciences
Alberto Molina-Cardin, Luis Dinis, Maria Luisa Osete
Summary: The model presented in this study is able to replicate the periodic reversals and excursions of the geomagnetic field by explaining the random perturbations affecting two coupled particles in potential energy. The temporal asymmetry of geomagnetic reversals is attributed to the model's out-of-equilibrium state, with a thermal imbalance between the two particles.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(2021)
Article
Geochemistry & Geophysics
Norbert R. Nowaczyk, Jiabo Liu, Birgit Plessen, Antje Wegwerth, Helge W. Arz
Summary: A detailed paleosecular variation (PSV) record from sediment cores recovered from the Arkhangelsky Ridge in the SE Black Sea provides insight into the geomagnetic field behavior during the pen-ultimate glacial period. The age constraints are determined by a composite oxygen isotope stratigraphy and U-Th-dated speleothem oxygen isotope records. The stacked paleomagnetic data records have a temporal resolution of 200 years.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Ron Shaar, Yves Gallet, Yoav Vaknin, Lilach Gonen, Mario A. S. Martin, Matthew J. Adams, Israel Finkelstein
Summary: Our understanding of the Earth's magnetic field intensity in the past has relied on paleointensity analysis. This study uses radiocarbon-dated archaeological materials from the Levant and Mesopotamia to construct a continuous curve of geomagnetic field intensity spanning 2500 years, providing unprecedented detail and resolution.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Environmental Sciences
Pavel Kovar, Marek Sommer
Summary: The movement of the South Atlantic Anomaly has been observed by spacecraft equipped with radiation detectors. CubeSats are expected to take over routine monitoring in the future. Recent observations show a westward drift of 0.33 degrees/year and a southward movement of 0.25 degrees/year, with the fluence maximum position showing higher scatter than the centroid position.
Article
Geochemistry & Geophysics
Yael A. Engbers, J. Michael Grappone, Darren F. Mark, Andrew J. Biggin
Summary: The South Atlantic Anomaly (SAA) is the most significant anomaly in the Earth's magnetic field. This study presents the first paleointensity data from Saint Helena, indicating a weak and unstable magnetic field in the South Atlantic region. These findings suggest that the SAA is not a single occurrence but part of a recurring pattern of weaknesses in the magnetic field.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geosciences, Multidisciplinary
Wilbor Poletti
Summary: The movement of the Earth's outer core generates the planet's magnetic field, which can be observed through asymmetries in the geomagnetic field at the Earth's surface. Studying these features is important for understanding the planet's interior and for multidisciplinary correlations.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2021)
Article
Engineering, Aerospace
Amar Kakad, Bharati Kakad
Summary: The magnetic field of the Earth has been decreasing over the past 200 years, with the most significant decreases observed in the South Atlantic Anomaly (SAA) and the southern pole region. The average magnetic field in the southern polar region is now weaker than the northern polar magnetic field, and this trend is also evident in ground magnetic field observations. The weakening of the geomagnetic field can have serious implications for our life, satellites, and climate.
ADVANCES IN SPACE RESEARCH
(2022)
Article
Engineering, Aerospace
Pankaj K. Soni, Bharati Kakad, Amar Kakad
Summary: The weakened geomagnetic field over the South Atlantic Anomaly (SAA) may lead to a deeper altitudinal reach of radiation belt particles. Research has shown that these particles have decreased their altitude by approximately 434-590 kms over the SAA region during the past century.
ADVANCES IN SPACE RESEARCH
(2022)
Article
Geosciences, Multidisciplinary
Linxi Chang, Shihong Zhang, Haiyan Li, Hanbiao Xian, Huaichun Wu, Tianshui Yang
Summary: Based on lines of geological evidence, it has long been believed that the south China craton (SCC) had a paleogeographic affinity with India during the Neoproterozoic era. However, the lack of coeval paleomagnetic data has made this connection ambiguous. New paleomagnetic results obtained from ca. 770 million year old mafic sills in SCC now provide critical constraints on the issue. These results, together with coeval paleomagnetic data from the global database, support a reconstruction in which SCC was connected with India via linkages with smaller continental blocks. The landmass formed by SCC and India was located at high-to-mid latitudes, far from Laurentia and Australia which were at low latitudes around 770 million years ago.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
S. A. Campuzano, F. J. Pavon-Carrasco, A. De Santis, A. Gonzalez-Lopez, E. Qamili
Summary: Research shows that geomagnetic jerks are related to the South Atlantic Anomaly (SAA) and the reversed flux patches (RFPs) within the SAA are associated with the secular acceleration of the geomagnetic field.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Geochemistry & Geophysics
Liu Wei, Zhao XiXi, Lin Jian, Zhao MingHui, Liu QingSong
Summary: The Philippine Sea Plate (PSP) and the South China Sea (SCS) are located in the convergent area of the Eurasian Plate, Pacific Plate, and Australia Plate, and are of great importance for tectonic reconstruction. This paper discusses the co-evolution of these two basins based on paleomagnetic data, submarine magnetic anomaly, seismic tomography, and geological constraints. It is suggested that the Shikoku Basin and the SCS were dynamically connected in the Oligocene, and the PSP rotated and separated from the SCS due to the Australia-SE Asia collision in the early Miocene.
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
(2022)
Article
Geosciences, Multidisciplinary
Lei Wu, Wenting Huang, Huaying Liang, J. Brendan Murphy, Uwe Kirscher, Ross N. Mitchell, Louise M. A. Hawkins, Galen P. Halverson, Yu J. Gu, Jian Zhang, Xijun Liu
Summary: The Devonian position of the South China Block (SCB) is uncertain due to contradictory Devonian paleopoles. Two characteristic remanent magnetization components were found in the Guanyang Devonian successions, with one likely reflecting syn-depositional magnetization and the other associated with the Late Devonian Liujiang orogeny.
Article
Geochemistry & Geophysics
Torsten Haberzettl, Thomas Kasper, Joseph S. Stoner, Jean Jacques Rahobisoa, Gerhard Daut
Summary: The paleomagnetic records derived from maar lakes in Madagascar provide valuable insights into the paleomagnetic secular variations in (southern) Africa, showing similarities with global geomagnetic field reconstructions and other geological records. These new data help distinguish reliable paleomagnetic data from potentially problematic ones, improving the understanding of paleomagnetic changes in the region.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Marta M. Zossi, Elda M. Zotto, Gustavo A. Mansilla
Summary: This study analyzed the effects on total column ozone, NOx, and ozone profiles in the South Atlantic Anomaly zone during two intense geomagnetic storms. The results showed a significant decrease in total column ozone after the storms, a significant increase in middle stratospheric heights, and a significant increase in NOx relative difference between 25 and 40 km during both storms.
PURE AND APPLIED GEOPHYSICS
(2021)
Article
Geosciences, Multidisciplinary
F. Miyake, I. P. Panyushkina, A. J. T. Jull, F. Adolphi, N. Brehm, S. Helama, K. Kanzawa, T. Moriya, R. Muscheler, K. Nicolussi, M. Oinonen, M. Salzer, M. Takeyama, F. Tokanai, L. Wacker
Summary: The C-14 data in tree rings indicate an extreme solar energetic particle event around 5410 BCE, similar to previously reported events in 774/775 CE, 992/993 CE, and around 660 BCE.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Astronomy & Astrophysics
F. Mekhaldi, F. Adolphi, K. Herbst, R. Muscheler
Summary: The threat of solar storms to modern society has attracted significant interest, with recent studies focusing on the content of cosmogenic radionuclides in tree rings and ice cores. Research suggests that Be-10 may not be suitable for detecting recent solar particle events, while Cl-36 is suitable for detecting extreme events.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2021)
Article
Geochemistry & Geophysics
Kristina Eriksson Stenstrom, Goran Skog, Christian Bernhardsson, Soren Mattsson, Anne Birgitte Nielsen, Mats Rundgren, Raimund Muscheler, Hans Linderson, Guillaume Pedehontaa-Hiaa, Christopher Raaf
Summary: The European Spallation Source (ESS) is a research facility under construction in Lund, Sweden, which will generate neutrons through spallation reactions. Along with the desired neutrons, radioactive by-products such as C-14 are produced. To ensure compliance with regulations, preoperational studies are being carried out, including mapping the radiation environment around the site. This study presents C-14 levels in environmental samples from Lund and southern Sweden between 2012 and 2020, and discusses a localized C-14 contamination event in 2009.
Review
Multidisciplinary Sciences
T. J. Heaton, E. Bard, C. Bronk Ramsey, M. Butzin, P. Koehler, R. Muscheler, P. J. Reimer, L. Wacker
Summary: Radiocarbon (C-14) is a key tracer in studying the Earth system, with updated calibration curves providing unprecedented accuracy in estimates of C-14 levels. These improvements open up new opportunities for more reliable and detailed analysis of the Earth and climate system, while also presenting challenges for the future.
Article
Geosciences, Multidisciplinary
Peter Kohler, Florian Adolphi, Martin Butzin, Raimund Muscheler
Summary: This article discusses the challenges in combining changes in C-14 production rate (Q) and carbon cycle to explain the reconstructed atmospheric Delta C-14 record, and analyzes possible reasons for this difficulty. Hypothetical Q values are derived using two different models and compared with data-based estimates. The results indicate a deficit in the current data-based approaches.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2022)
Article
Geochemistry & Geophysics
Gabriel West, Andreas Nilsson, Alexis Geels, Martin Jakobsson, Matthias Moros, Francesco Muschitiello, Christof Pearce, Ian Snowball, Matt O'Regan
Summary: This study investigates the behavior of the geomagnetic field in polar regions during the late Holocene period. By analyzing well-dated sediment cores from the Chukchi Sea, Arctic Ocean, the authors provide valuable insights into the changes in the geomagnetic field in the Arctic over the past few thousand years.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Multidisciplinary Sciences
Nicolas Brehm, Marcus Christl, Timothy D. J. Knowles, Emmanuelle Casanova, Richard P. Evershed, Florian Adolphi, Raimund Muscheler, Hans-Arno Synal, Florian Mekhaldi, Chiara I. Paleari, Hanns-Hubert Leuschner, Alex Bayliss, Kurt Nicolussi, Thomas Pichler, Christian Schluchter, Charlotte L. Pearson, Matthew W. Salzer, Patrick Fonti, Daniel Nievergelt, Rashit Hantemirov, David M. Brown, Ilya Usoskin, Lukas Wacker
Summary: The Sun occasionally produces intense solar energetic particle (SEP) events that disrupt the near-Earth radiation environment. By analyzing C-14 concentrations in tree-rings, two spikes in atmospheric C-14 occurring in ancient times were discovered, providing critical information on the occurrence of extreme solar events in the past.
NATURE COMMUNICATIONS
(2022)
Article
Geosciences, Multidisciplinary
Long Nguyen, Neil Suttie, Andreas Nilsson, Raimund Muscheler
Summary: In this study, a new Bayesian model is proposed to reconstruct both solar activity and geomagnetic dipole moment from cosmogenic radionuclide data. The model takes into account the variations of both processes on overlapping timescales.
EARTH PLANETS AND SPACE
(2022)
Article
Meteorology & Atmospheric Sciences
F. Adolphi, K. Herbst, A. Nilsson, S. Panovska
Summary: Cosmogenic radionuclide records from polar ice cores are used to reconstruct past changes in solar activity, space weather, geomagnetic field, and carbon cycle. The proportionality of the ice core radionuclide records to the global mean production rate changes has been debated. Through atmospheric mixing model experiments and comparison to independent data, it is found that mixing scenarios without complete tropospheric mixing result in a polar bias. A correction function is proposed to restore proportionality to the global mean signal.
JOURNAL OF GEOPHYSICAL RESEARCH-ATMOSPHERES
(2023)
Article
Geosciences, Multidisciplinary
Giulia Sinnl, Florian Adolphi, Marcus Christl, Kees C. Welten, Thomas Woodruff, Marc Caffee, Anders Svensson, Raimund Muscheler, Sune Olander Rasmussen
Summary: During the last glacial, Greenland experienced a cold stadial phase with two short warm interstadials. Greenland ice-core calcium data shows two periods of high atmospheric dust loading, which is not well understood. The Chinese Hulu Cave speleothems also exhibit an climate signal during the same time. Antarctic ice cores show a relative warming, interpreted as a counterpart to a cool phase in the Northern Hemisphere. New Be-10 datasets from Greenland and Antarctic ice cores are examined to test the agreement between different timescales. Evidence of an event similar to the Maunder Solar Minimum is found in the new Be-10 datasets, supporting a synchronization with the Chinese speleothem around 22 kyr b2k. The offset between the Greenland ice-core chronology and the Antarctic chronology is determined to be 125 +/- 40 years, and the offset between the speleothem and ice-core timescales is determined to be 375 years for GICC05 and 225 years for WD2014, respectively.
CLIMATE OF THE PAST
(2023)
Article
Geosciences, Multidisciplinary
Giulia Sinnl, Mai Winstrup, Tobias Erhardt, Eliza Cook, Camilla Marie Jensen, Anders Svensson, Bo Mollesoe Vinther, Raimund Muscheler, Sune Olander Rasmussen
Summary: The revision of the ice-core timescale is crucial for the understanding of past climate. By synchronizing multiple ice cores, the new timescale is found to be younger than the previous version, with a difference of about 13 years at 3835 years ago. The most recent 800 years are largely unaffected by the revision, but there is a steady increase in the offset between timescales between 800 and 2000 years ago, with the steepest offset occurring between 800 and 1100 years ago.
CLIMATE OF THE PAST
(2022)