Article
Geochemistry & Geophysics
Peter Robinson, S. A. McEnroe, R. J. Harrison, K. Fabian, F. Heidelbach, M. Jackson
Summary: Lamellar magnetism in natural rocks is a unique source of remanent magnetization, distinct from common bulk magnetic moments in ferrimagnetic minerals. This type of magnetism has been identified as a cause for magnetic anomalies with high Koenigsberger ratio. The study explores the physical origins and interactions of lamellar magnetism, highlighting the effects of lamellar shapes on magnetic coupling and the acquisition of magnetization in ilmenite lamellae. Simplified models are developed to assess and explain these observations in relation to exchange bias and lattice-preferred orientation.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
David J. Dunlop
Summary: The study on the magnetic properties of various iron-bearing minerals at different temperatures reveals changes in domain structures, which may lead to thermal unblocking or vortex development in single-domain grains and addition or remobilization of domain walls in multidomain grains. The saturation remanence decreases more rapidly than saturation magnetization with increasing measurement temperature, suggesting thermal effects and domain wall changes in the minerals studied.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Mike J. Jackson, Bruce Moskowitz
Summary: The Verwey transition temperature in magnetite shows a bimodal distribution, with most lithological subsets having a peak around 120 K and one or more additional peaks at lower temperatures. This distribution pattern is a general characteristic of natural magnetites and provides context for interpreting natural processes or conditions during formation or alteration of magnetite.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Liao Chang, Hoabin Hong, Fan Bai, Shishun Wang, Zhaowen Pei, Greig A. Paterson, David Heslop, Andrew P. Roberts, Baochun Huang, Lisa Tauxe, Adrian R. Muxworthy
Summary: The quasi-linear field-dependence of remanence is crucial for sedimentary relative palaeointensity studies. Magnetic-mineral inclusions within sediments play a significant role in the remanent magnetization and can affect the recording efficiency and inclination shallowing. The size of silicate particles in sediments can impact the inclination shallowing and magnetic moment behavior in Earth-like magnetic fields.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Thomas A. Berndt, Liao Chang, Greig A. Paterson, Changqian Cao
Summary: Most rocks acquire a thermoremanent magnetization (TRM) when they cool down, and this process affects palaeointensity estimates and unblocking temperatures in thermal demagnetization experiments. The relationship between cooling rates and blocking temperatures has been theoretically established, but experimental verification is limited due to the difficulty of accurately determining cooling rates. Experiments show that the cooling rate effect on blocking temperatures holds true for ideal magnetic recorders, but natural samples may deviate from theoretical predictions and affect palaeointensity estimates.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
David J. Dunlop
Summary: The study focuses on the variation of magnetic properties of magnetite with different grain sizes from room temperature to the Curie point, covering various magnetic behavior. Understanding the magnetic properties of magnetite can help in unraveling the mechanisms of signal acquisition and retention.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Suzanne A. McEnroe, Nathan Church, Karl Fabian, Marianne F. Stange, Antonius T. J. van Helvoort
Summary: This study provides a comprehensive analysis of mineralogical and rock magnetic data for 57 samples from the high magnetic anomaly area in the Stardalur Caldera in Iceland, confirming that the anomaly is due to an unusually high intensity of remanent magnetization carried by magnetite. The study also shows that the concentration of magnetite in the area is at most twice as high as that in typical basalts, and the efficiency of remanent magnetization acquisition is at least three times higher. However, the detailed mechanism for the extreme overefficiency of remanent magnetization acquisition remains a mystery.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
S. A. Badejo, A. R. Muxworthy, A. Fraser, M. Neumaier, J. R. Perkins, G. R. Stevenson, R. Davey
Summary: This study investigates the potential of magnetic minerals as a proxy for hydrocarbon migration pathways by testing core samples from the Tay Fan in the Central North Sea. Results show a variety of magnetic minerals present in similar concentrations, with an increasing presence of authigenic iron sulphides along the identified lateral hydrocarbon migration pathway. This suggests mineral magnetic techniques could be used to quickly identify biodegradation severity or oil maturity in core samples, which can then be used to calibrate petroleum systems models.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Andrei Kosterov, Mary Kovacheva, Maria Kostadinova-Avramova, Pavel Minaev, Natalia Salnaia, Leonid Surovitskii, Svetlana Yanson, Elena Sergienko, Petr Kharitonskii
Summary: The study conducted detailed rock magnetic analysis on archaeological ceramics from Bulgaria and Russia, revealing the presence of magnetically soft and hard minerals with differing unblocking temperatures. A unique high coercivity, stable, low-unblocking temperature phase was identified in some samples, while others contained a combination of high- and low-unblocking temperature, magnetically hard phases.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Mark W. Hounslow, Chorng-Shern Horng, Vassil Karloukovski
Summary: Prior studies on RRM and ARM(ROT) have shown promise in identifying magnetic minerals in earth materials, but the calibration of measurements to different magnetic mineral types and microstructural controls has been challenging due to the use of varying spin rates and AF intensities. This study demonstrates that a RAPID magnetometer can be used to achieve a wide range of RRM and ARM(ROT) characteristics within a practical rotation rate range of 0.25-3 Hz [rps]. The calibration of RRM-ARM(ROT) behavior using sediment magnetic mineral extracts and well characterized rock samples reveals differences in effective field values and ARM(ROT) ratios at different rotation rates, allowing for discrimination of grain size and distinction of different magnetic minerals.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
D. K. Niezabitowska, R. Szaniawski
Summary: The Holy Cross Mountains (HCM) in Poland is a unique natural outcrop of Palaeozoic rocks, located within the Trans-European Suture Zone. The HCM has been divided into two major units, the southern (Kielce Unit) and northern (Lysogory Unit) parts, and their relative position with respect to the Baltica continent during the Silurian period is still a topic of discussion. This study used rock magnetic measurements to interpret the palaeoenvironmental conditions and discuss the terranes' relative position.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geosciences, Multidisciplinary
Aditya Pratama, Dini Nurfiani, Putu Billy Suryanata, Taufik Ismail, Gabriela Nogo Retnaningtyas Bunga Naen, Mirzam Abdurrachman, Wilfridus Ferdinando Supriyadi Banggur, Nining Sumawati Asri, Ratika Benita Nareswari, Satria Bijaksana, Muhammad Hanif, Estu Kriswati, Idham Andri Kurniawan, Nugroho Imam Setiawan
Summary: Understanding the evolution of magma storage conditions on Krakatau volcano is crucial for assessing past and present conditions and forecasting future hazards. This study combined geochemistry, rock magnetic, and petrology to infer the evolution of magma storage conditions from different periods of volcanic activity. The findings reveal the characteristics of magma storage in different phases and their relationship to the ongoing evolution of Krakatau.
FRONTIERS IN EARTH SCIENCE
(2023)
Article
Geochemistry & Geophysics
A. N. Mahgoub, B. Garcia-Amador, L. M. Alva-Valdivia
Summary: This study reports paleomagnetic directions and intensity values obtained from 27 sites in the Baja California Peninsula, northwestern Mexico. The results show weak geomagnetic field during the middle-late Miocene compared to the Pliocene period, suggesting a global nature of low dipole moment during that time.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2021)
Article
Geochemistry & Geophysics
Josef Jezek, Frantisek Hrouda
Summary: By investigating the anisotropy of in-phase and out-of-phase magnetic susceptibility, the study sheds light on the characteristics of AC magnetic susceptibility in rocks and minerals caused by eddy currents. The results show that EC susceptibility is strongly frequency dependent and closely related to the shape of the materials.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geochemistry & Geophysics
B. Eid, F. Lhuillier, V. P. Shcherbakov, V. V. Shcherbakova
Summary: This study provides new absolute and relative paleointensity data from a basaltic sequence in Ethiopia, finding no robust correlation between changes in dipole moment and reversal frequency over the past 155 million years. However, the results are consistent with the predicted paleosecular-variation proxy trend from numerical dynamo simulations.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geosciences, Multidisciplinary
Caitlin E. Leslie, Daniel J. Peppe, Thomas E. Williamson, Matthew Heizler, Mike Jackson, Stacy C. Atchley, Lee North, Barbara Standhardt
GEOLOGICAL SOCIETY OF AMERICA BULLETIN
(2018)
Article
Geochemistry & Geophysics
Mike Jackson, Julie Bowles
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2018)
Article
Geochemistry & Geophysics
Andrea R. Biedermann, Dario Bilardella, Mike Jackson, Lisa Tauxe, Joshua M. Feinberg
EARTH AND PLANETARY SCIENCE LETTERS
(2019)
Article
Geochemistry & Geophysics
J. A. Bowles, S. -C. L. L. Lappe, M. J. Jackson, E. Arenholz, G. van der Laan
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2019)
Article
Geochemistry & Geophysics
Andrea R. Biedermann, Mike Jackson, Dario Bilardello, Joshua M. Feinberg
GEOPHYSICAL JOURNAL INTERNATIONAL
(2019)
Article
Geochemistry & Geophysics
D. K. Niezabitowska, R. Szaniawski, M. Jackson
GEOPHYSICAL JOURNAL INTERNATIONAL
(2019)
Article
Geochemistry & Geophysics
Michael W. R. Volk, Michael Eitel, Mike Jackson
GEOPHYSICAL JOURNAL INTERNATIONAL
(2019)
Article
Geosciences, Multidisciplinary
Charles Aubourg, Mike Jackson, Maxime Ducoux, Mohannad Mansour
Article
Geochemistry & Geophysics
Wentao Huang, Michael J. Jackson, Mark J. Dekkers, Yang Zhang, Bo Zhang, Zhaojie Guo, Guillaume Dupont-Nivet
EARTH AND PLANETARY SCIENCE LETTERS
(2019)
Article
Geosciences, Multidisciplinary
Wentao Huang, Michael J. Jackson, Mark J. Dekkers, Peat Solheid, Bo Zhang, Zhaojie Guo, Lin Ding
GEOPHYSICAL RESEARCH LETTERS
(2019)
Article
Geochemistry & Geophysics
Andrea R. Biedermann, Mike Jackson, Michele D. Stillinger, Dario Bilardello, Joshua M. Feinberg
Article
Geochemistry & Geophysics
Andrea R. Biedermann, Mike Jackson, Dario Bilardello, Joshua M. Feinberg
Article
Geochemistry & Geophysics
Andrea R. Biedermann, Mike Jackson, Martin Chadima, Ann M. Hirt, Joshua M. Feinberg
GEOPHYSICAL JOURNAL INTERNATIONAL
(2020)
Article
Geochemistry & Geophysics
Wentao Huang, Michael J. Jackson, Mark J. Dekkers, Peat Solheid, Yang Zhang, Shihu Li, Zhaojie Guo, Lin Ding
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2020)
Article
Geosciences, Multidisciplinary
Mohammad Paknia, Paolo Ballato, Ghasem Heidarzadeh, Francesca Cifelli, Behrooz Oskooi, Joshua Feinberg, Mike Jackson, Dario Bilardello, Francesco Salvini, Majid Mirzaie Ataabadi, Meisam Tadayon, Mohammad Reza Ghassemi, Massimo Mattei
Summary: In this study, anisotropy of magnetic susceptibility (AMS) was combined with fault kinematic analysis and sedimentologic data to analyze deposits of the Upper Red Formation in the intermontane Tarom Basin of NW Iran. The study found that the Miocene extension observed in the basin is not regionally pervasive and not controlled by large-scale processes, suggesting that the normal faults were gravity instabilities induced by sedimentary processes rather than extensional tectonics.
JOURNAL OF ASIAN EARTH SCIENCES
(2021)