Article
Geochemistry & Geophysics
Kristijan Rajic, Hugues Raimbourg, Vincent Famin, Benjamin Moris-Muttoni, Donald M. Fisher, Kristin D. Morell, Aurelien Canizares
Summary: We conducted a structural study on the Kodiak accretionary complex in Alaska, USA to understand its thermal structure and the processes of exhumation. The complex consists of tectonic melanges and coherent units, with melanges characterized by shear deformation and coherent units affected by horizontal shortening. Our findings indicate peak temperatures ranging from 220 to 400 degrees C, with the highest temperatures recorded in the central part of the complex. Based on structural and thermal data, we conclude that the rocks in the Kodiak complex experienced stages of burial and exhumation, with vertical motions reaching up to 13 km. The exhumation resulted from prism thickening and surficial erosion.
Article
Geochemistry & Geophysics
Kristijan Rajic, Hugues Raimbourg, Vincent Famin, Benjamin Moris-Muttoni, Donald M. Fisher, Kristin D. Morell, Aurelien Canizares
Summary: A study on the structural and thermal characteristics of the Kodiak accretionary complex in Alaska, USA suggests that the complex experienced two stages of burial and exhumation. The study also reveals a dome-like structure in the central part of the complex and records subsidence episodes along the southeastern border. The rates of vertical motion in the complex are comparable to estimates in modern margins.
Article
Geochemistry & Geophysics
Samuele Papeschi, Paola Vannucchi, Takehiro Hirose, Keishi Okazaki
Summary: This study documents the existence of an exhumed plate boundary shear zone, known as the Norsi-Cavo Complex (NCC), which developed during the early stages of the Apennines in Northern Italy. The NCC is composed of oceanic sediments and serpentinites and is continuously exposed on the island of Elba. The authors interpret the formation of the NCC as a result of material transfer from the upper plate to the subduction channel through tectonic erosion at the base of the prism. The findings suggest that the NCC formed during eastward subduction of the Ligurian Ocean and ceased when the continental margin entered the subduction.
Article
Geosciences, Multidisciplinary
Naresh C. Ghose, Athokpam Krishnakanta Singh, Amrita Dutt, Sashimaren Imtisunep
Summary: The ophiolite belt in Nagaland-Manipur states in Northeast India represents a segment of the ocean floor and upper mantle with high-pressure metamorphic assemblages, including a newly discovered aegirine-bearing metabasic rocks. These rocks may have formed during an early stage in the nascent forearc when temperatures were elevated enough to generate Na-rich fluid fluxes.
GEOLOGICAL JOURNAL
(2022)
Article
Geosciences, Multidisciplinary
Changsheng Guo, Pengchao Sun, Dongping Wei
Summary: The wedge subduction of the Antarctic Plate is different from the normal subduction, with the Chile Triple Junction (CTJ) playing a crucial role in controlling both the subduction pattern and the thermal structure of the overriding plate. Factors such as slab age, thickness, and dip angle can influence the subduction process and the lithospheric thermal structure.
FRONTIERS IN EARTH SCIENCE
(2021)
Article
Geosciences, Multidisciplinary
Amin Rashidi, Denys Dutykh, Christian Beck
Summary: This study evaluates the potential hazard of tsunami scenarios along the Lesser Antilles subduction zone, considering its specificities. The results indicate that potential earthquakes in the region can produce powerful tsunamis, with the impacts being more severe in the northern part, particularly on Guadeloupe.
Article
Geochemistry & Geophysics
Jorge Sanhueza, Gonzalo Yanez, W. Roger Buck, Jaime Araya Vargas, Eugenio Veloso
Summary: The subduction of an active spreading center in subduction zones disrupts typical arc-type magmatism and intraplate seismicity, enhances backarc plateau lava emplacement, and changes tectonics and topographic relief. The Chile Triple Junction is an ideal setup to study mid-ocean ridge subduction. 2-D numerical petrological-thermomechanical modeling shows slab separation and the opening of a slab window, with migrated partial melts explaining low viscosity and seismic velocity anomalies in the slab window and the geochemical signature of various magmatic features.
GEOCHEMISTRY GEOPHYSICS GEOSYSTEMS
(2023)
Article
Geochemistry & Geophysics
Jia HongRui, Wei DongPing
Summary: The study reveals the subduction of the Chile ridge under the South America plate at the Chile triple junction. The Nazca plate and Antarctic plate exhibit distinct subduction characteristics in different directions, leading to the change of nature of the CTJ during various processes.
CHINESE JOURNAL OF GEOPHYSICS-CHINESE EDITION
(2021)
Article
Geochemistry & Geophysics
Earl E. Davis, Joseph J. Farrugia
Summary: Ground-motion amplification has been observed in the outer Cascadia subduction zone accretionary prism, with well-tuned response at the prism sites in both vertical and horizontal components, leading to enhanced surface-wave accelerations during large earthquakes.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Geochemistry & Geophysics
Alok Kumar, Jyotiranjan S. Ray, P. E. Binusarma, N. Awasthi, Bivin G. George, M. G. Yadava, Rajneesh Bhutani, S. Balakrishnan, Kanchan Pande
Summary: Mud volcanoes at convergent margins serve as pathways for ejecting clay minerals and fluids originating deep within forearcs, providing insight into shallow level processes in subduction zones. Detailed mineralogical, geochemical, and isotopic studies reveal that the mud breccia contains materials derived from altered oceanic crust and terrigenous sediment, with the former contributing the majority of the composition.
Article
Geosciences, Multidisciplinary
Xinchang Zhang, Yi Yan, Yildirim Dilek, Wen -Huang Chen, Yehua Shan
Summary: This study investigates the origin and sedimentary evolution of the Taiwan accretionary prism, and finds that the Chinese mainland is not the exclusive contributor to sedimentation in the Hengchun Peninsula, but that the subducting South China Sea oceanic lithosphere is also a significant source. The study also suggests that the Taiwan accretionary prism was partly exposed prior to -11.6 Ma, earlier than previous estimates, and that underplating of seamounts and/or thinning of the Chinese continental margin, along with wedge extrusion tectonics, played a role in the early-stage uplift. This research provides a better understanding of the erosion history of the South China Sea oceanic crust and sedimentary records in Taiwan, and emphasizes the importance of soft exhumation mechanism in plate convergence zones.
MARINE AND PETROLEUM GEOLOGY
(2023)
Article
Geochemistry & Geophysics
Guo Cheng, William D. Barnhart, Shaoyang Li
Summary: This study uses InSAR time-series data to investigate the non-linear viscoelastic deformation of the Makran accretionary prism in southeast Pakistan. The results show that the prism exhibits elastic thinness and the non-linear viscoelastic relaxation of the deep portions can explain the post-seismic surface deformation. The presence of power-law rheology within the lower wedge impacts the estimated plate coupling and the stress state in the subduction system.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2022)
Letter
Geosciences, Multidisciplinary
Kaya Iwamoto, Nobuaki Suenaga, Shoichi Yoshioka, Francisco Ortega-Culaciati, Matthew Miller, Javier Ruiz
Summary: The southern Chile subduction zone is a complex tectonic environment where the Nazca and Antarctic plates subduct underneath the South American plate. A three-dimensional thermomechanical model was constructed to study the subduction process near the Chile Triple Junction. The temperature distributions and water content within the slabs were analyzed to understand the relationship between plate subduction and volcano formation.
GEOSCIENCE LETTERS
(2023)
Review
Geosciences, Multidisciplinary
Guido M. Gianni, Sofia Perez Lujan
Summary: The study emphasizes that understanding the combination of both perspectives, the space-time arc pattern and the associated geological framework, provides the best approach to unravel the dominant process controlling arc migration and shut-off. By diagnosing features from the geological record, it can help distinguish the dominant geodynamic process.
EARTH-SCIENCE REVIEWS
(2021)
Article
Geochemistry & Geophysics
Yueyang Xia, Heidrun Kopp, Dirk Klaeschen, Jacob Geersen, Bo Ma, Michael Schnabel
Summary: This passage describes the Java - Lesser Sunda margin and its subduction of oceanic basement relief, discussing the effects of seabed topography on seafloor morphology, upper plate structure, and decollement position. It also highlights the importance of understanding the tectonic parameters that influence whether the margin falls within the neutral or erosional domain.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
C. Peirce, I Grevemeyer, N. W. Hayman, H. J. A. Van Avendonk
Summary: The Swan Islands transform fault marks the southern boundary of the Cayman Trough in the Caribbean and represents the ocean-continent transition of the Honduras continental margin. The CAYSEIS experiment reveals the crustal structure of an actively evolving transform continental margin and the nature of the crust and uppermost mantle beneath the ridge-transform intersection (RTI).
GEOPHYSICAL JOURNAL INTERNATIONAL
(2022)
Article
Geosciences, Multidisciplinary
Yu Ren, Jacob Geersen, Ingo Grevemeyer
Summary: Oceanic transform faults (OTFs) are an integral part of seafloor spreading and plate tectonics. A new study has systematically quantified the variations in transform morphology and their dependence on spreading rate and age-offset. The research found that the length, width, and depth of OTFs are more systematically correlated with age-offset than spreading rate. This supports recent geodynamic models that propose cross-transform extension scaling with age-offset as a key process in transform dynamics. Furthermore, OTFs with larger age-offsets tend to have longer, wider, and deeper valleys on a global scale.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
V Yanez-Cuadra, F. Ortega-Culaciati, M. Moreno, A. Tassara, N. Krumm-Nualart, J. Ruiz, A. Maksymowicz, M. Manea, V. C. Manea, J. Geng, R. Benavente
Summary: This study presents a novel methodology to estimate interplate coupling, upper plate rigid motion, and surface strain simultaneously using GNSS-derived velocities. The modeling results reveal three megathrust regions with high tsunamigenic earthquake potential within the Atacama Seismic Gap, and suggest that surface motion is mainly controlled by strain rather than rigid motion.
GEOPHYSICAL RESEARCH LETTERS
(2022)
Article
Geosciences, Multidisciplinary
Peng Guo, Satish C. Singh, Venkata A. Vaddineni, Ingo Grevemeyer, Erdinc Saygin
Summary: Oceanic crust is formed through a combination of magmatic and tectonic processes, with the formation of the lower crust still under debate. Seismic data from young crust formed at the Mid-Atlantic Ridge reveal alternating layers of high and low velocities, with the uppermost low-velocity layer associated with hydrothermal alteration. The layering supports the intrusion of melt as sills at different depths to form the lower crust, indicating a stable process of lower crustal accretion.
Article
Multidisciplinary Sciences
Bo Ma, Jacob Geersen, Dietrich Lange, Dirk Klaeschen, Ingo Grevemeyer, Eduardo Contreras-Reyes, Florian Petersen, Michael Riedel, Yueyang Xia, Anne M. Trehu, Heidrun Kopp
Summary: The updip limit of seismic rupture plays a major role in determining the size of a tsunami caused by a megathrust earthquake. Using seismic reflection data, researchers have found that the rupture area of the 2014 Iquique earthquake in offshore Northern Chile was characterized by low fluid pressure, while north and updip of the rupture area, there was excess fluid pressure. This knowledge can help assess the potential for future shallow rupture and improve understanding of the physical state of shallow plate boundaries.
NATURE COMMUNICATIONS
(2022)
Article
Geochemistry & Geophysics
Carlos Herrera, Francisco Pasten-Araya, Leoncio Cabrera, Bertrand Potin, Efrain Rivera, Sergio Ruiz, Raul Madariaga, Eduardo Contreras-Reyes
Summary: This study investigates the 2020 Calama earthquake sequence and compares it with other significant earthquakes in the area. The results show that the Calama main shock has similar stress drop and dynamic rupture parameters as the nearby Michilla and Jujuy earthquakes. The Calama sequence occurred in the upper lithospheric mantle with lower aftershock productivity and a less hydrated environment.
GEOPHYSICAL JOURNAL INTERNATIONAL
(2023)
Article
Geology
Zhikui Guo, Sibiao Liu, Lars Ruepke, Ingo Grevemeyer, Jason P. Morgan, Dietrich Lange, Yu Ren, Chunhui Tao
Summary: Recent research shows that the crust in oceanic transform faults is thinner than in adjacent fracture zones, challenging the concept of transform faults as conservative plate boundaries. This study also reveals the addition of secondary magmatic material at the transition to passive fracture zones.
Article
Geosciences, Multidisciplinary
Bo Ma, Jacob Geersen, Dirk Klaeschen, Eduardo Contreras-Reyes, Michael Riedel, Yueyang Xia, Anne M. Trehu, Dietrich Lange, Heidrun Kopp
Summary: This study accurately maps the structures related to ridge subduction under the marine forearc in the Chilean subduction zone using advanced seismic reflection data processing. The subducting ridge-related topography causes upward bulging of the entire upper plate and the presence of kilometer-scale anticlinal structures. Frontal subduction erosion is observed in the area affected by the subducting ridge, while a small frontal prism and sediment cover are found in the region where isolated seamounts subduct.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2023)
Article
Geosciences, Multidisciplinary
F. A. Gonzalez, J. P. Bello-Gonzalez, E. Contreras-Reyes, A. M. Trehu, J. Geersen
Summary: Seismic investigations and scientific ocean drilling projects have revealed the geological heterogeneity in marine forearc basins. However, the mechanisms for offshore basin formation and evolution, especially for erosive margins, are not fully understood. This study uses bathymetry, seismic reflection lines, and P-wave velocities to explore the shallow structure of the northern Chilean erosive convergent margin. The findings suggest that tectonically controlled forearc basins may form due to enhanced subduction erosion.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2023)
Article
Geosciences, Multidisciplinary
J. A. Ruiz, A. Perez, F. Ortega-Culaciati, E. Contreras-Reyes, D. Comte
Summary: The Mw 8.3 Illapel earthquake on September 16, 2015, had a rupture length of over 200 km along strike. Two large aftershocks occurred in close proximity and beyond the northern limit of the Illapel rupture. Kinematic rupture models showed that the first event had an updip propagation from the hypocenter and later a bilateral mode with large slip to the south. The second event relocated southwest and re-ruptured an area already broken by the first event. The spatial slip distribution of both events suggested slip in the usually aseismic upper portion of the megathrust.
JOURNAL OF SOUTH AMERICAN EARTH SCIENCES
(2023)
Article
Geochemistry & Geophysics
Eduardo Contreras-Reyes, Sebastian Obando-Orrego, Ingo Grevemeyer
Summary: This study uses simultaneous P- and S-wave data to investigate the seismic structure of the oceanic crust. The results show different seismic properties at different locations, indicating hydrothermal alteration and compaction processes. The abrupt change in seismic properties at the layer 2/3 transition is attributed to epidotization and crack-change properties.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Yu Ren, Dietrich Lange, Ingo Grevemeyer
Summary: The Blanco transform fault system (BTFS) off Oregon is highly segmented without prominent fracture zones longer than 100 km. The western part is focused at deep troughs, while the eastern part lacks a transform valley and instead developed the Blanco Ridge. The BTFS can be divided into an eastern mature transform system and a western immature transform system that is still evolving.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Yuhan Li, Ingo Grevemeyer, Shuichi Kodaira, Gou Fujie
Summary: The seismic and velocity models of the Izu arc-backarc system reveal the processes of crustal formation and subduction zone recycling in the mantle. The study shows that basaltic volcanism plays a crucial role in the transformation process from arc to continental crust, while rhyolitic volcanism may relate to the juvenile stage of arc evolution or the remelting of middle crust. Additionally, mafic restite and cumulates have delaminated and formed extremely low mantle velocities, and the lack of high velocities in the lower crust of the Shikoku Basin rules out hydrous melts or anomalous mantle trapped during subduction zone reconfiguration.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2023)
Article
Geochemistry & Geophysics
Andrei Maksymowicz, Daniela Montecinos-Cuadros, Daniel Diaz, Maria Jose Segovia, Tomas Reyes
Summary: The objective of this study is to analyze the density structure of the continental forearc in the northern segment of the 1960 Valdivia earthquake. Regional and local density models were obtained using gravity data and were constrained by geophysical and geological information. The results show the segmentation of the continental wedge and a high-density anomaly below the onshore forearc basin. This study suggests that the structure of the overriding plate plays a role in the seismotectonic process in subduction zones.
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)
