Article
Environmental Sciences
Alexandra R. McGoran, James S. Maclaine, Paul F. Clark, David Morritt
Summary: Most mesopelagic fishes sampled in the South Atlantic were contaminated with microplastics, while shallow water dwelling species did not ingest any. Overall, 66.7% of the studied fishes were found to contain microfibers, with viscose fibers associated with sanitary products being common.
FRONTIERS IN MARINE SCIENCE
(2021)
Article
Geochemistry & Geophysics
Hao Zhang, Mechita C. Schmidt-Aursch, Wolfram H. Geissler, Junhui Xing
Summary: Through analyzing seismic recordings collected in the Tristan da Cunha region, the sources of ambient noise in the middle of the South Atlantic were investigated. It was found that secondary microseisms were strong and correlated with local wave heights, indicating that local wave interactions were the dominant source of noise. Additionally, distant sources of secondary microseisms were identified, located in the Southeast Pacific Ocean and influenced by the blocking effect of the Drake Passage on ocean currents and wave systems.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Biodiversity Conservation
M. N. Bester, L. J. Stansfield, T. Glass, P. J. N. de Bruyn
Summary: The study found that some top predator populations in the South Atlantic and South Indian oceans are declining due to reduced food availability caused by climate change. By analyzing the fish diet of sub-Antarctic fur seals, researchers discovered significant differences in the prey consumed by populations around the Subtropical Convergence compared to those in the Polar Frontal Zone, supporting the idea that major ocean frontal zones act as natural dispersal borders for fish in the Southern Ocean.
Article
Plant Sciences
Juliet Brodie, Leanne Melbourne, Robert J. Mrowicki, Paul Brickle, Stephen Russell, Sue Scott
Summary: A taxonomic study of Corallina from Tristan da Cunha and the Falkland Islands revealed two new species, as well as their relationships with other related species. The study used molecular and morphological methods to distinguish between different Corallina species and uncovered cryptic diversity within the genus. Further taxonomic efforts are needed in the South Atlantic region to better understand the diversity of Corallina species.
EUROPEAN JOURNAL OF PHYCOLOGY
(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
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
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
Geology
Leilane Souza Scribelk, Sergio de Castro Valente
Summary: This study presents petrological data of magmatic rocks in the Santos Basin, which show characteristics consistent with OIB. Geochemical modelling suggests that the basalts in the basin have different sources and are emitted from different vents. The results also indicate a possible role of the Tristan da Cunha plume tail in the petrogenesis of the alkaline basalts, rather than the local subcontinental lithospheric mantle.
INTERNATIONAL GEOLOGY REVIEW
(2023)
Article
Geochemistry & Geophysics
Hao Zhang, Wolfram H. Geissler, Mechita C. Schmidt-Aursch, Raffaele Bonadio
Summary: In this study, ambient noise tomography was used to investigate the crust and uppermost mantle shear velocity structure in the Tristan da Cunha region in the South Atlantic. The results reveal a shallow conduit of low shear velocity beneath the volcanic archipelago, possibly representing a magmatic plumbing system. Additionally, indications of low shear velocities were observed in the uppermost mantle beneath seamounts in the southwest of the island.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
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
Hagay Amit, Filipe Terra-Nova, Maxime Lezin, Ricardo I. Trindade
Summary: The South Atlantic Anomaly (SAA) is a region on Earth's surface with a particularly low intensity of the magnetic field. Accurate characterization of the SAA is crucial for understanding core dynamics, geodynamo, and addressing societal issues. Research indicates that the SAA area and center exhibit time dependency, including periods of stability, eastward drift, and rapid southward drift.
EARTH PLANETS AND SPACE
(2021)
Article
Multidisciplinary Sciences
Andreas Nilsson, Neil Suttie, Joseph S. Stoner, Raimund Muscheler
Summary: The strength of the Earth's magnetic field has rapidly decreased over the past two centuries, coinciding with the growth of the South Atlantic Anomaly, leading to speculation about a field reversal. Through indirect observations over the past 9,000 years, evidence of recurrent hemispherical field asymmetries related to millennial-scale variations in the dipole moment has been identified, suggesting potential ancient analogs.
PROCEEDINGS OF THE NATIONAL ACADEMY OF SCIENCES OF THE UNITED STATES OF AMERICA
(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
Astronomy & Astrophysics
V. Pierrard, S. Benck, E. Botek, S. Borisov, A. Winant
Summary: The analysis of proton flux variations observed by the Energetic Particle Telescope (EPT) on the PROBA-V satellite from May 7, 2013 to October 2022 reveals an inverse correlation between proton fluxes and solar phase. The fluxes are higher at low latitudes during solar minimum, particularly at the northern border of the South Atlantic Anomaly (SAA). This modulation of the inner belt is primarily influenced by increased atmospheric interactions during solar maximum. While Solar Energetic Particle (SEP) events inject energetic protons at high latitudes, the inner belt at low L remains unaffected due to long-term proton trapping. However, geomagnetic storms, including those following SEP events, can cause proton losses at the outer border of the proton belt due to magnetic field disturbances. A double peak in the proton belt is observed only in the EPT channel of 9.5-13 MeV during long periods of measurement. The narrow gap between the two peaks, located around L = 2, resembles a splitting of the proton belt, separating the SAA into North and South regions. The high-resolution measurements of PROBA-V/EPT provide new insights into the source and loss mechanisms of the proton radiation belt at Low Earth Orbit (LEO).
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2023)
Article
Entomology
Ismail Doker, Edward A. Ueckermann, Vladimir A. Khaustov, Omid Joharchi, Christine Hanel
Summary: This paper describes a new species Neoseiulus cunhaensis and presents a key to the species of the paspalivorus species group in the genus Neoseiulus Hughes.
SYSTEMATIC AND APPLIED ACAROLOGY
(2021)
Article
Geochemistry & Geophysics
Anett Blischke, Bryndis Brandsdottir, Martyn S. Stoker, Carmen Gaina, Ogmundur Erlendsson, Christian Tegner, Saemundur A. Halldorsson, Helga M. Helgadottir, Bjarni Gautason, Sverre Planke, Anthony A. P. Koppers, John R. Hopper
Summary: Volcanostratigraphic and igneous province mapping of the Jan Mayen microcontinent and Iceland Plateau Rift region provide new insights into the development of rift systems during breakup processes, revealing two breakup events, seven distinct tectono-magmatic phases, and four rift zones.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Geosciences, Multidisciplinary
Y. Yamazaki, J. Matzka, C. Stolle, G. Kervalishvili, J. Rauberg, O. Bronkalla, A. Morschhauser, S. Bruinsma, Y. Y. Shprits, D. R. Jackson
Summary: The study introduces a new geomagnetic activity index Hpo, which has higher time resolution and can accurately characterize severe geomagnetic storms compared to the traditional index Kp.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Allison A. Price, Matthew G. Jackson, Janne Blichert-Toft, Kevin Konrad, Michael Bizimis, Anthony A. P. Koppers, Jasper G. Konter, Valerie A. Finlayson, John M. Sinton
Summary: By geochemically characterizing and dating a suite of lavas from the Samoan hotspot and its downstream region, this study sheds light on the contributions and origins of the hotspot activity. The findings suggest a rejuvenation and mixing of Samoan and Cook-Austral hotspot materials, and highlight possible causes for the missing segment of the Arago-Rurutu hotspot track. Additionally, the study provides insights into anomalous volcanism within the Samoan hotspot track.
JOURNAL OF PETROLOGY
(2022)
Article
Geochemistry & Geophysics
L. Tauxe, H. Asefaw, N. Behar, A. A. P. Koppers, R. Shaar
Summary: Using a modified Thellier-Thellier experiment and strict selection criteria, this study found that the Pleistocene paleomagnetic axial dipole moment in Northern Israel is slightly higher than that of Iceland and even higher than that of Antarctica. The data from the Hawaiian drill core also showed higher values compared to Northern Israel. Furthermore, the results suggest that the average paleomagnetic intensity in mid-latitude Northern Hemisphere is higher than that of the Southern Hemisphere and latitudes higher than 60 degrees N. These findings indicate that the weaker intensities found at high latitudes cannot be attributed to inadequate sampling or low-quality data, and could be due to long-lived non-axial dipole terms in the geomagnetic field.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2022)
Article
Astronomy & Astrophysics
Yosuke Yamazaki, Gabriel Soares, Jurgen Matzka
Summary: Modeling studies have predicted that geophysical events like earthquakes and volcanos can cause acoustic resonance in the atmosphere, leading to oscillation of the geomagnetic field. However, observations of this phenomenon have been limited. A recent submarine volcano eruption in the Pacific Ocean provided an opportunity to investigate geomagnetic effects associated with acoustic resonance. The eruption resulted in geomagnetic oscillations, primarily in the Pc 5 band, at a location approximately 835 km away, confirming the presence of atmospheric oscillation due to acoustic resonance.
JOURNAL OF GEOPHYSICAL RESEARCH-SPACE PHYSICS
(2022)
Article
Geosciences, Multidisciplinary
Lesleis Nagy, Wyn Williams, Lisa Tauxe, Adrian Muxworthy
Summary: Paleointensities are crucial for understanding Earth's formation and evolution, but current experimental protocols often fail due to the assumption of uniformly magnetized rocks. Non-uniform magnetized grains are more common, causing a multiplicity of stable domain states that affect paleointensity estimation. Recognizing this behavior is vital for obtaining reliable records and enhancing our understanding of Earth.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Astronomy & Astrophysics
Thomas L. North, Gareth S. Collins, Thomas M. Davison, Adrian R. Muxworthy, Sarah C. Steele, Roger R. Fu
Summary: By simulating the impact of a shock wave on ALH 84001, researchers were able to determine the meteorite's thermodynamic and physical response, providing insights into its deformation events and ejection from Mars.
Article
Materials Science, Multidisciplinary
R. Moreno, W. Williams, A. R. Muxworthy, G. A. Paterson, D. Heslop
Summary: FORCs is a characterization technique for magnetic materials that is widely used in research fields. Recent experimental works have shown that the interpretation of FORC data lacks understanding, even for simple cases. This study addresses this problem by analytically explaining the meaning of FORC data and proposing a strategy to extract the interaction field between magnetic structures.
JOURNAL OF MAGNETISM AND MAGNETIC MATERIALS
(2022)
Article
Geochemistry & Geophysics
Jing Hu, Yong Zhang, Dong Jia, Adrian Muxworthy, David Selby, Yongxiang Li, Matthew J. J. Brzozowski, Guoqi Wei, Jian Cao, Hongwei Yin, Wei Li
Summary: This study combines paleomagnetic dating analysis and Re-Os isotope dating to resolve the controversial evolution of the Permian reservoir in the Longmen Shan orogen, South China. The results show two remagnetization events and two periods of oil generation and accumulation. This combined approach provides a reliable way to track the sequence of oil formation and accumulation even in complex tectonic settings.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Editorial Material
Geosciences, Multidisciplinary
Richard Douglas Elmore, Adrian R. Muxworthy, Gerhard Heij, W. Crawford Elliott
FRONTIERS IN EARTH SCIENCE
(2023)
Article
Multidisciplinary Sciences
Peter C. Davidson, Anthony A. P. Koppers, Takashi Sano, Takeshi Hanyu
Summary: This study provides high-precision 40Ar/39Ar data to improve the understanding of the eruptive history of the Ontong Java Plateau (OJP). The results suggest that OJP formed over a protracted period of at least 6 million years, which is younger than previously estimated. This indicates that OJP may not be the cause of Ocean Anoxic Event 1a (OAE 1a), but it could have played a role in OAE 1b.
Article
Astronomy & Astrophysics
Michael D. D. Hartinger, Xueling Shi, Craig J. J. Rodger, Ikuko Fujii, E. Joshua Rigler, Karl Kappler, Jurgen Matzka, Jeffrey J. J. Love, Joseph B. H. Baker, Daniel H. H. Mac Manus, Michael Dalzell, Tanja Petersen
Summary: Previous studies have shown that large-amplitude geomagnetically induced current (GIC) related to magnetospheric Ultra Low Frequency (ULF) waves are more common at latitudes above 60 degrees and with periods longer than 120 seconds. Conversely, GIC amplitudes are smaller at lower latitudes and with shorter wave periods, and there are fewer reports of waves associated with GIC at lower latitudes. This study aims to investigate whether these trends are due to the undersampling of ULF waves in commonly available measurements with 60-second sampling intervals. Data from the 29-31 October 2003 geomagnetic storm, with sampling intervals of 0.5-10 seconds, is used to examine waves with periods...
SPACE WEATHER-THE INTERNATIONAL JOURNAL OF RESEARCH AND APPLICATIONS
(2023)
Article
Geochemistry & Geophysics
Brendan Cych, Lisa Tauxe, Geoffrey Cromwell, John Sinton, Anthony A. P. Koppers
Summary: Paleomagnetists assume that the Earth's magnetic field behaves like a Geocentric Axial Dipole (GAD). Directional data compiled over the past 5 million years support this assumption, but paleointensity data do not. The failure of GAD can be attributed to arbitrary selection criteria, varying age distribution of data, and the possibility of a non-dipolar field. This study presents a consistent methodology for analyzing paleointensity data and compares results from different studies. The findings suggest that the time-averaged paleointensities from Hawaii and Antarctica are not GAD-like for the past 1.5 million years. However, GAD cannot be ruled out before this time. Differences in global records of field strength can be unrelated to methodology or age.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Evelyn B. B. Baker, Adrian R. R. Muxworthy
Summary: In this study, the behavior of grain-growth chemical remanent magnetizations (gCRM) and thermoremanences (TRM) was investigated using a thermally activated Preisach model. It was found that gCRM intensity is more sensitive to growth rate than previously modeled, while TRMs are more sensitive to changes in coercivity distribution and magnetostatic interactions. The results also showed that gCRMs cannot accurately determine ancient magnetic field intensities using conventional methods based on thermoremanence acquisition.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
P. C. Davidson, A. A. P. Koppers, J. G. Konter
Summary: About 120 million years ago, a large amount of lava erupted on the Pacific Ocean floor, forming the proposed largest volcanic system on Earth called Ontong Java Nui. Plate tectonics then caused this system to break up into five fragments, which drifted away from each other in the western Pacific Ocean. By analyzing dated samples and conducting geochemical analysis, it has been found that these three main fragments separated extremely rapidly, possibly 3 times faster than current plate tectonics, and stopped spreading in their current configuration about 20 million years after the initial eruption. Additionally, the magma source in the Ellice Basin and Osbourn Basin differed slightly from the initial volcanism of Ontong Java Nui as a whole. These new age and geochemical data are crucial for further understanding the eruption and breakup history of Ontong Java Nui.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2023)
Article
Geochemistry & Geophysics
Lingyu Zhang, Kristoffer Szilas
Summary: This study presents new petrological and geochemical data for the Narssaq Ultramafic Body (NUB) in the Itsaq Gneiss Complex of SW Greenland. The results indicate that the ultramafic rocks of NUB are not mantle residues, but instead represent crustal cumulates derived from high-Mg magmas.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Rong Xu, Sarah Lambart, Oliver Nebel, Ming Li, Zhongjie Bai, Junbo Zhang, Ganglan Zhang, Jianfeng Gao, Hong Zhong, Yongsheng Liu
Summary: This study investigated the iron isotope compositions of Cenozoic basalts in Southeast China, finding significant variations related to different types of basalts and their respective sources.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
C. J. Ebinger, Miriam C. Reiss, Ian Bastow, Mary M. Karanja
Summary: The East African rift system is formed above mantle upwellings and the formation of rifts is related to lithospheric thinning and magmatic activity. The amount of splitting varies spatially and the fast axes are predominantly parallel to the orientation of the rifts. Thick lithospheric modules have less splitting and different orientations, which may indicate mantle plume flow. Splitting rotates and increases in strength as it enters the rift zones, suggesting that the anisotropy is mainly present at shallow depths.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Correction
Geochemistry & Geophysics
Ekaterina Rojas-Kolomiets, Owen Jensen, Michael Bizimis, Gene Yogodzinski, Lukas Ackerman
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Robert W. Nicklas, Igor S. Puchtel, Ethan F. Baxter
Summary: Oxygen fugacity is a fundamental parameter for understanding redox processes in igneous systems. This study compares the Fe-XANES oxybarometry method with the V-in-olivine method for evaluating fO(2) in MORB lavas. The results show that the V-in-olivine method is not applicable to samples with low MgO content, and that the majority of Archean komatiite sources have lower fO(2) than modern MORB.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Chunfei Chen, Stephen F. Foley, Sebastian Tappe, Huange Ren, Lanping Feng, Yongsheng Liu
Summary: The volatile components CO2 and H2O play a major role in mantle melting and heterogeneity. In this study, Ca isotopes were used to trace the lithological heterogeneity in alkaline magmatic rocks. The results revealed the presence of K-richterite and carbonate components as the source of alkaline magmas with low delta 44/40Ca values. These findings highlight the importance of Ca isotopes as a robust tracer of lithological variation caused by volatiles in the Earth's upper mantle.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Timothee Jautzy, Gilles Rixhon, Regis Braucher, Romain Delunel, Pierre G. Valla, Laurent Schmitt, Aster Team
Summary: Although the current approach to estimate catchment-wide denudation rates using only 10Be concentrations has made significant progress in geomorphology, this study argues for the inclusion of 26Al measurements and testing of steady-state assumptions in slow eroding, formerly glaciated landscapes. The study conducted measurements of both 10Be and 26Al in stream sediments from the Vosges Massif in France and found that elevation, slope, channel steepness, and precipitation were the primary factors controlling denudation rates. The study also revealed a significant relationship between the extent of past glaciation and the cosmogenic (un-)steadiness in the stream sediments.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)
Article
Geochemistry & Geophysics
Erik van der Wiel, Douwe J. J. van Hinsbergen, Cedric Thieulot, Wim Spakman
Summary: Numerical models of Earth's mantle dynamics can predict the vigour and mixing of mantle flow, and the average slab sinking rates are an unexplored parameter that can provide intrinsic information on these characteristics. Through numerical experiments, it has been found that slab sinking rates are strongly correlated with mantle convection and mixing, and may explain geochemical observations from hotspot volcanoes.
EARTH AND PLANETARY SCIENCE LETTERS
(2024)