Article
Geochemistry & Geophysics
Xiuli Yan, Bo Zhang, Guodong Wang, Tao Yang, Jianye Chen
Summary: This study investigates fault rocks and protoliths from the Shaba outcrop (Beichuan County) on the Yingxiu-Beichuan Fault ruptured during the 2008 Wenchuan Mw 7.9 earthquake using rock magnetic measurements and electron microscopic observations. The results show that pyrrhotite, a product of pyrite alteration at high temperatures, is present in fault gouges, indicating frictional heating during earthquake slip. Additionally, the presence of goethite suggests the presence of hot fluids within the fault zone. These findings suggest that thermal pressurization may be a plausible mechanism of coseismic fault weakening during the Wenchuan earthquake.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2023)
Article
Geochemistry & Geophysics
Giacomo Pozzi, Marco M. Scuderi, Elisa Tinti, Manuela Nazzari, Cristiano Collettini
Summary: Fault stability is closely related to the frictional and healing properties of fault rocks and associated fabrics. The reactivation and slip behavior of dolomite-anhydrite analog faults are controlled by fault fabrics. The study reveals that changes in normal stress can result in different fault behaviors, such as large stress drops and high slip velocities, or low stress drops and slow stick-slip events. The integration of microstructural and mechanical data suggests that frictional and chemically assisted healing processes play a relevant role in developing large instabilities in natural faults. Additionally, fault rock heterogeneity modulates the slip velocity function and the dynamics of repeating stick-slip cycles.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geosciences, Multidisciplinary
Yangyang Wang, Jianfa Chen, Sijia Li, Shiyuan Wang, Deyang Shi, Weibing Shen
Summary: The study evaluates the mineralogical and geochemical variations in fault rocks in the Shaba area of the Yingxiu-Beichuan surface rupture zone of the Mw 7.9 Wenchuan earthquake. The results show certain regularities in the fault zone and suggest that fluid-rock interactions play a significant role in fault weakening.
JOURNAL OF STRUCTURAL GEOLOGY
(2022)
Article
Geochemistry & Geophysics
F. Paglialunga, F. Passelegue, S. Latour, A. Gounon, M. Violay
Summary: Fluids in the Earth's crust affect the stability and dynamics of faults, and viscous fluids have been found to play a significant role in fault reactivation and earthquake ruptures. In experiments using analogue material, it was discovered that the presence of viscous lubricants along faults reduces frictional resistance, increases nucleation length, and decreases fracture energy. Furthermore, the higher the viscosity of the fluids, the greater the reduction in frictional strength and increase in nucleation length.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Astronomy & Astrophysics
Dario Bilardello
Summary: The study conducted magnetic and rock-magnetic research on sedimentary rocks in the state of Sao Paulo, Brazil, confirming the rocks were largely remagnetized during the Cretaceous. Analysis of AMS showed that it records primary sedimentary fabrics reflecting depositional environments and paleocurrent conditions of the rocks.
EARTH AND SPACE SCIENCE
(2021)
Article
Geosciences, Multidisciplinary
Yohan Park, Takehiro Hirose, Jin-Han Ree
Summary: Frictional healing is a key mechanism in controlling fault strength recovery, and carbonate fault mirrors exhibit unique behavior with significantly lower frictional healing rates. The presence of densely packed sintered nanogouges in fault mirrors hinders the chemical and physical processes that lead to frictional healing, potentially causing aseismic creep.
GEOPHYSICAL RESEARCH LETTERS
(2021)
Article
Geosciences, Multidisciplinary
T. Miyamoto, T. Hirono, Y. Yokoyama, S. Kaneki, Y. Yamamoto, T. Ishikawa, A. Tsuchiyama, I Katayama, Y. Yabe, M. Ziegler, R. J. Durrheim, H. Ogasawara
Summary: The cores recovered from deep South African Gold Mines during the International Continental Scientific Drilling Program project reveal fault breccia and altered lamprophyres. The breccia and lamprophyres have high magnetic susceptibilities and low friction coefficients, which are inconsistent with earthquakes. The altered lamprophyres may be the host rocks of the 2014 Orkney earthquake, but the frictional complexity may have influenced the magnitudes and distributions of the main- and aftershocks.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
D. Elhanati, R. Issachar, T. Levi, R. Weinberger
Summary: Magnetic fabric analyses using AMS are a powerful tool in geological research, allowing for identification of dominant magnetic phases through measurements at different temperatures and providing a reliable method for geological interpretation in complex settings.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
G. Pozzi, C. Collettini, M. M. Scuderi, T. Tesei, C. Marone, A. Amodio, M. Cocco
Summary: Magnetite-rich serpentinites, found in low-strain domains of shear zones, have the potential to nucleate unstable slip and induce earthquakes, especially at low slip velocities. Through laboratory experiments, we demonstrate that these rocks display strong sensitivity to loading rate and undergo two deformation mechanisms depending on mineralogical composition and structure, leading to stable and unstable slip.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geochemistry & Geophysics
Luca Dal Zilio, Taras Gerya
Summary: This study investigates the role of hydraulic properties on fault in controlling seismic and aseismic fault slip. Results show that fault permeability and porosity play a key role in determining the predominant slip mode.
Article
Energy & Fuels
Mianmo Meng, Hongkui Ge, Yinghao Shen, Wenming Ji, Qianyou Wang
Summary: In this study, the irreducible water saturation and its controlling factors in the Upper Paleozoic Taiyuan and Shihezi Formations were investigated. The results showed that the saturation was related to porosity, permeability, average pore diameter, and specific surface area in both formations. Furthermore, the saturation can be further analyzed by dividing it into saturation controlled by small throat or capillary force. Overall, this study improves our understanding of the mechanism and controlling factors of water occurrence.
Article
Geochemistry & Geophysics
Li-Wei Kuo, Chien-Cheng Hung, Haibing Li, Stefano Aretusini, Jianye Chen, Giulio Di Toro, Elena Spagnuolo, Fabio Di Felice, Huan Wang, Jialiang Si, Hwo-Shuenn Sheu
Summary: The 2008 Wenchuan earthquake caused surface ruptures along the Longmenshan fault belt, with the Yingxiu-Beichuan fault and the Guanxian-Anxian faults being the most affected. Frictional experiments were conducted on the gouge materials from the Guanxian-Anxian faults, revealing that wet gouges have lower friction coefficients compared to those under room humidity conditions. Additionally, the gouges exhibited enhanced velocity-strengthening behavior at intermediate velocities, indicating a potential barrier to slip acceleration during fault propagation.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geosciences, Multidisciplinary
Alfons Berger, Marco Herwegh
Summary: This study investigates the interaction between hydrothermal and deformation processes in active fault zones using the example of the Grimselpass breccia fault in the Central Alps. The results show that there are different types of tectonites in the fault zone, which differ in terms of microstructure, mass and volume gain/loss, and cementation. The study also reveals the importance of precipitation of SiO2-rich cements in reducing permeability and increasing strength of the fault rocks.
GEOLOGICAL MAGAZINE
(2022)
Article
Physics, Fluids & Plasmas
Anna Pomyalov, Yuri Lubomirsky, Lara Braverman, Efim A. Brener, Eran Bouchbinder
Summary: A numerical study is conducted on self-healing slip pulses, which are solitonic structures propagating in frictional systems. The solutions show diverging length and strongly inertial propagation velocities when the driving stress approaches the frictional strength at a local minimum. An approximate scaling theory explains these observations quantitatively. The derived pulse solutions exhibit significant spatially-extended dissipation and an unconventional edge singularity.
Article
Geosciences, Multidisciplinary
Alexey Ostapchuk, Kseniya Morozova, Vadim Markov, Dmitry Pavlov, Maxim Popov
Summary: The spectrum of fault slip modes ranges from fast ruptures to slow slip events, with mounting evidence that a single fault can host multiple modes. Laboratory experiments show a high inverse correlation between fault friction and the b-value of AE frequency-amplitude distribution. The self-organization of gouge-filled faults at the micro scale plays a key role in controlling the frictional behavior of faults with multiple slip modes.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Geochemistry & Geophysics
Caicai Liu, Huafeng Qin, Eric C. Ferre, Wei Wang, Kuang He, Chenglong Deng
Summary: Understanding the acquisition of chemical remagnetization is crucial for assessing the stability of primary chemical remanent magnetization and the impact of diagenesis on the paleomagnetic record. A study on a red soil sequence in southern China suggests pervasive remagnetization and challenges the previous interpretation of CRM lock-in. The study highlights the need for caution when using magnetostratigraphy to date highly weathered aluminum-rich red sediments.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geosciences, Multidisciplinary
Haosen Wang, Xing Xu, Congcong Gai, Jiabo Liu, Yi Zhong, Xiaodong Jiang, Yanan Zhang, Eric C. Ferre, Kuang He, Qingsong Liu
Summary: This study explores the relationships among the abundance of magnetofossils, magnetic properties, and paleoenvironmental factors in marine sediments. It identifies a link between the abundance of magnetofossils and paleoenvironmental changes in the northwestern South China Sea. The study also proposes a model that explains the relationship between the anisotropy of magnetic susceptibility fabric and magnetofossil abundance.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geochemistry & Geophysics
Tao Yang, Mark J. Dekkers, Xixi Zhao, Katerina E. Petronotis, Yu-Min Chou
Summary: This study provides insights into a novel pathway of greigite formation controlled by turbidites and bioturbation. The research also suggests that early diagenetic greigite can preserve primary (quasi-)syn-sedimentary magnetic records.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Article
Geochemistry & Geophysics
Jianye Chen
Summary: In this study, the slip stability of a fluid-infiltrated fault is analyzed using a microphysical friction model. The results show the possibility of four different modes of slow slips without invoking inertia, suggesting that the microphysical model is favorable for generating slow slips.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Jianye Chen, Luuk B. Hunfeld, Andre R. Niemeijer, Christopher J. Spiers
Summary: High-velocity friction experiments on simulated fault gouges sheared at high normal stress and to low displacement were performed, revealing the relationship between constitutive parameters and normal stress, providing important constraints for numerical modeling of induced rupture propagation. The experiments also found that different rock types in the Groningen field exhibit varying levels of resistance to rupture and proposed a micrometer-scale fault weakening mechanism.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geosciences, Multidisciplinary
Yunfeng Nie, Huaichun Wu, Sara Satolli, Eric C. Ferre, Meinan Shi, Qiang Fang, Ye Xu, Shihong Zhang, Haiyan Li, Tianshui Yang
Summary: The continuous sedimentary cores recovered at IODP Site U1505 in the South China Sea provide an opportunity for paleoceanography and paleoclimate reconstruction. Detailed rock- and paleomagnetic studies were conducted, revealing the prevalence of low-coercivity pseudosingle domain magnetite in the sediment samples. By correlating the polarity sequence with the Geomagnetic Polarity Time Scale 2020 and using biostratigraphic data, a magnetostratigraphic age model was constructed. This study also identified Milankovitch cycles and established a high-resolution astronomical time scale, providing insights into sedimentation rate variations and a hiatus across the Brunhes-Matuyama boundary.
PALEOCEANOGRAPHY AND PALEOCLIMATOLOGY
(2023)
Article
Geosciences, Multidisciplinary
Liao Chang, Zhaowen Pei, Pengfei Xue, Shishun Wang, Zhaoping Wang, Wout Krijgsman, Mark J. J. Dekkers
Summary: This study investigates the origin of multipolarity in Miocene greigite-bearing sediments using electron microscopic and magnetic analyses. It is found that there is a magnetic softening and partial transformation of iron sulfides to magnetite and pyrrhotite in the sediments, leading to the change from single polarity to multipolarity. A new greigite self-reversal model is proposed to explain the commonly observed antiparallel polarities, which has significant implications in geochronology, tectonics, and paleoenvironment.
GEOPHYSICAL RESEARCH LETTERS
(2023)
Article
Geology
John I. Ejembi, Sally L. Potter-McIntyre, Anna Paltseva, Eric C. Ferre
Summary: The Wanakah Formation and Tidwell Member of the Morrison Formation in western Colorado during the Middle-Late Jurassic exhibit different types of paleosols and pedogenic carbonates, indicating variable redox conditions and a sub-humid to humid paleoclimate with seasonal precipitations. Clay mineralogy analysis suggests episodic wetting and drying, leading to the formation of illite from smectite alteration. The study provides new insights into the local and regional paleoclimatic and paleoenvironmental conditions during the Middle Jurassic in western Colorado.
INTERNATIONAL GEOLOGY REVIEW
(2023)
Article
Geochemistry & Geophysics
Nina Zamani, Gerhard W. Heij, Eric C. Ferre, Michael A. Murphy, Brian Bagley
Summary: This article focuses on the Heart Mountain Slide in Wyoming and uses the anisotropy of magnetic susceptibility (AMS) to study the ultracataclastic deformation of carbonates. The results reveal a different sliding direction than previously thought and demonstrate the changes in magnetic susceptibility due to the breakdown of iron sulfides caused by frictional heating. This study is significant for understanding deformation processes in carbonates, particularly in seismic faults.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Wentao Huang, Shanshan Niu, Mark J. Dekkers, Peter C. Lippert, Dario Bilardello, Peat Solheid, Bo Zhang, Guillaume Dupont-Nivet, Douwe J. J. van Hinsbergen, Lin Ding
Summary: Paleomagnetic investigations of Paleocene lavas from Dianzhong Formation in Linzhou basin of southern Lhasa terrane are essential for determining the timing and paleolatitude of the initial India-Asia collision. However, controversy exists regarding the preservation of primary remanent magnetization in these rocks. This study finds that hydrothermal alteration has significantly impacted the original magnetic carrier, resulting in the contamination or replacement of the primary remanence by thermoviscous and chemical remanent magnetizations.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Mark J. Dekkers, Wout Hanckmann, Simo Spassov, Thilo Behrends
Summary: Siderite is an important sink for iron in the geochemical cycling of iron, but its detection is challenging due to its fine-grained nature and low concentrations. This study explores the potential of low-temperature magnetometry for analyzing siderite. The results show that the presence of siderite can be best diagnosed by evaluating a combination of heating curves and the remanence ratio.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2023)
Editorial Material
Geochemistry & Geophysics
Isabelle Manighetti, Rachel Abercrombie, Yves Bernabe, Michael Bostock, Mark J. Dekkers, Satoshi Ide, Douglas R. Schmitt, Shin-Chan Han, Paul Tregoning
Summary: The editors of JGR-Solid Earth express their gratitude to the peer reviewers who contributed in reviewing articles for the journal in 2022.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Jinyu Chen, Jianye Chen, Lu Yao, Xi Ma
Summary: This study investigated the effects of shear deformation on the friction and electrical conductivity of synthetic quartz-graphite mixtures. The results showed that specimens with higher graphite content exhibited higher electrical conductivity. Mixtures with lower graphite content (as low as 3.4% by volume) may cause high conductivity anomalies in natural shear zones.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)