Article
Geochemistry & Geophysics
Ekaterina Rojas-Kolomiets, Owen Jensen, Michael Bizimis, Gene Yogodzinski, Lukas Ackerman
Summary: Mo isotope compositions are used to study the sources of magmatic systems in the Aleutian arc. The study reveals the relative contributions of subducting oceanic crust, fluid-rich sources, subducted sediments, and upper mantle in the chemical composition of Aleutian arc magmas. The results indicate that different sections of the arc have distinct isotopic characteristics and play a significant role in tracing subduction zone fluids.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Multidisciplinary Sciences
Bin Zhao, Roland Burgmann, Dongzhen Wang, Jian Zhang, Jiansheng Yu, Qi Li
Summary: This study used GPS observations to derive the slip distribution of the 2020 Mw 7.8 Simeonof Island earthquake and analyzed the subsequent afterslip. The results indicate that the mainshock ruptured at depths of 30-40 km, and afterslip occurred both updip and downdip of the mainshock rupture.
NATURE COMMUNICATIONS
(2022)
Article
Oceanography
Simon Barbot, Marion Lagarde, Florent Lyard, Patrick Marsaleix, Pascale Lherminier, Catherine Jeandel
Summary: This study provides new insights into the interpretation of GEOVIDE particle measurements, identifying potential resuspension sites caused by internal tides along the western Iberian shelf slope. The study uses a regional model and reanalysis method to determine the transport pathways for particles from the resuspension sites to the GEOVIDE stations. It highlights the importance of using a numerical tidal model to accurately identify resuspension sites, as the commonly used bathymetry slope method is not sufficient.
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS
(2022)
Article
Multidisciplinary Sciences
Taryn Lopez, Tobias P. Fischer, Terry Plank, Alberto Malinverno, Andrea L. Rizzo, Daniel J. Rasmussen, Elizabeth Cottrell, Cynthia Werner, Christoph Kern, Deborah Bergfeld, Tehnuka Ilanko, Janine L. Andrys, Katherine A. Kelley
Summary: Subduction plays a crucial role in transporting volatiles and creating a habitable Earth. This study uses isotopes to track the movement of carbon from subduction to volcanic outgassing along the Aleutian-Alaska Arc. The findings reveal significant variations in the isotopic composition of volcanic gases due to different recycling efficiencies and subduction characteristics. Fast and cool subduction releases a higher percentage of sediment-derived organic carbon to the atmosphere through degassing, while slow and warm subduction favors the recycling of altered oceanic crust carbon. These results challenge previous assumptions about carbon recycling in subduction zones and highlight the limitations of subducting organic carbon as an atmospheric carbon sink over long time scales.
Article
Environmental Sciences
Qiang Li, Hezhong Yuan, Hui Li, Christopher Main, Jessica Anton, Deb P. Jaisi
Summary: This research used multi-isotope proxies to track P sources and evaluate their contributions in Love Creek, a coastal estuary in Delaware. Plant debris and soils from forest sources were found to be dominant sources of P in freshwater sites, while agricultural soil sources gradually dominated in the saline water portion of the creek as the salinity gradient decreased. The variations in P loads due to weather-related discharge, changing land use and activities, and seasons reflected the difficulty in accurately estimating sources.
SCIENCE OF THE TOTAL ENVIRONMENT
(2021)
Article
Geochemistry & Geophysics
Long Li, Yuhan Qi, Yunzhe Chen, Kan Li, Fang Huang, Pierre Cartigny
Summary: The study examined the fixed nitrogen component in arc lavas from Kick'em Jenny (KEJ) to shed light on two longstanding controversies in the recycling of subducting slab material. The results indicate that the nitrogen isotopic signature in the lavas is best explained by a mixing between the mantle and two distinct endmembers, suggesting sediment recycling into the mantle source. Additionally, the modeling results show that the arc crust is not a major repository of subducted nitrogen in the Lesser Antilles.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Computer Science, Artificial Intelligence
Kaiser Asif, Lu Zhang, Sybil Derrible, J. Ernesto Indacochea, Didem Ozevin, Brian Ziebart
Summary: Weld evaluation is typically done after the welding process, which may result in material waste and lengthy repairs. Manual inspections are also often required even for automated welds. Therefore, there is a need for a real-time weld quality monitoring method with a decision-making strategy to improve productivity and automation in welding.
JOURNAL OF INTELLIGENT MANUFACTURING
(2022)
Article
Multidisciplinary Sciences
C. Skinner, A. C. Mill, M. D. Fox, S. P. Newman, Y. Zhu, A. Kuhl, N. V. C. Polunin
Summary: Coral reef food webs are heavily subsidized by planktonic production, with offshore pelagic sources playing a significant role in sustaining reef predators. This highlights the importance of allochthonous energetic subsidies throughout the reef ecosystem.
Article
Environmental Sciences
Anqi Zhang, Kun Lei, Qi Lang, Yi Li
Summary: In this study, multiple stable isotope signatures were used to investigate the sources and transformations of nitrogen (N) in the Qiantang River-Hangzhou Bay river-estuarine water continuum. The results showed that nitrification was the dominant N transformation process, with sewage being the main source of N. This study provides important insights into the integrated management of N contamination in the land-ocean interface.
SCIENCE OF THE TOTAL ENVIRONMENT
(2022)
Article
Geochemistry & Geophysics
Lucien Nana Yobo, Alan D. Brandon, Chris Holmden, Kimberly Lau, James Eldrett
Summary: This study investigates the sources of nutrients during ocean anoxic events, proposing that massive eruptions of Large Igneous Provinces triggered the events. Results suggest that global warming associated with volcanic CO2 loading into the atmosphere increased continental weathering rates during ocean anoxic events, enhancing nutrient supplies to the oceans.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2021)
Article
Geochemistry & Geophysics
Alexander A. Iveson, Madeleine C. S. Humphreys, Ivan P. Savov, Jan C. M. de Hoog, Stephen J. Turner, Tatiana G. Churikova, Colin G. Macpherson, Tamsin A. Mather, Boris N. Gordeychik, Lubomira Tomanikova, Samuele Agostini, Keiji Hammond, David M. Pyle, George F. Cooper
Summary: The chemistry of primitive arc rocks provides insights into the compositional variability in the mantle wedge and slab-derived inputs to subduction-related magmatism. By analyzing olivine-hosted melt inclusions from the Kamchatka arc, systematic variations in element ratios are observed, which provide evidence for subduction-related metasomatism and mantle melting degrees. Across-arc variations in B isotopes reflect variable contributions of slab-derived components to depleted mantle compositions, with signals of compositional heterogeneity preserved during magma assembly and storage in the crust.
EARTH AND PLANETARY SCIENCE LETTERS
(2021)
Article
Geochemistry & Geophysics
Yang Yu, Xiao-Long Huang, Sun-Lin Chung, Jie Li, Yu-Ming Lai, Iwan Setiawan, Min Sun
Summary: Molybdenum isotopes are used as diagnostic tracers for crustal and mantle components in arc magmatism. This study investigates the mechanism of Mo isotopic variation in the Sunda arc magmatism using whole-rock Mo-Sr-Nd-Hf-Pb isotopic data from Java, Indonesia. The results suggest that Mo isotopic variations in the Java arc rocks are likely caused by metasomatism in the mantle wedge by hybrid agents, including melts from subducted sediments and melts from the subducted altered upper oceanic crust.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Engineering, Marine
Tanita Averes, Jacobus L. A. Hofstede, Arfst Hinrichsen, Hans-Christian Reimers, Christian Winter
Summary: The study discusses the uncertainties in calculating littoral sediment budgets from cliff retreat, and provides the first area-wide budget assessment along the sediment-starved Baltic Sea coastline of Schleswig-Holstein.
JOURNAL OF MARINE SCIENCE AND ENGINEERING
(2021)
Article
Geochemistry & Geophysics
Xinghua Jia, Daoyuan Sun
Summary: The study reveals that in the Ryukyu arc-trough system, the continental crust varies in depth from 22 to 27 kilometers, with the thickness gradually decreasing from the middle OT to 15 kilometers beneath the southern OT. In the transition zone from the middle OT to the continental shelf, there is a 10 kilometer Moho offset phenomenon.
JOURNAL OF GEOPHYSICAL RESEARCH-SOLID EARTH
(2021)
Article
Engineering, Environmental
Douglas R. Tait, Isaac R. Santos, Sebastien Lamontagne, James Z. Sippo, Ashley Mcmahon, Luke C. Jeffrey, Damien T. Maher
Summary: Rivers are not the only source of nutrients for the Great Barrier Reef; submarine groundwater discharge also plays a significant role. However, internal recycling processes still dominate the nutrient budget, suggesting the need for a shift in management focus to protect the reef from excess nutrients.
ENVIRONMENTAL SCIENCE & TECHNOLOGY
(2023)
Article
Geochemistry & Geophysics
A. H. Caruthers, S. M. Marroquin, D. R. Grocke, M. L. Golding, M. Aberhan, T. R. Them, Y. P. Veenma, J. D. Owens, C. A. McRoberts, R. M. Friedman, J. M. Trop, D. Szucs, J. Palfy, M. Rioux, J. P. Trabucho-Alexandre, B. C. Gill
Summary: The study provides new evidence supporting a long duration of the Rhaetian and constraints the Triassic-Jurassic boundary to a 6-meter interval in the section based on diverse biostratigraphic and isotopic data from the Late Triassic-Early Jurassic sedimentary succession in southern Alaska. The record from Grotto Creek, in conjunction with previous data, shows consistent features on a global scale but also reveals local heterogeneities compared to some Tethyan records, raising questions about regional overprinting of the global signal and highlighting unresolved regional vs. global scale of some presumed carbon cycle perturbations.
EARTH AND PLANETARY SCIENCE LETTERS
(2022)
Article
Geochemistry & Geophysics
Xinming Chen, Siqi Li, Sean M. Newby, Timothy W. Lyons, Fei Wu, Jeremy D. Owens
Summary: Thallium, vanadium isotopes, and other elements in organic-rich sediments can be influenced by the 'Fe and Mn shuttle' mechanism, which transports elements associated with iron and manganese oxide phases formed under mildly oxidizing conditions laterally and vertically to deeper waters. However, this mechanism may not strongly affect thallium and vanadium isotopes in extreme cases of water column redox stratification. Further research is needed to understand the isotopic signals in various settings.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geochemistry & Geophysics
Yunchao Shu, Sune G. Nielsen, Veronique Le Roux, Jerzy Blusztajn, Shun Guo, Fang Huang
Summary: In this study, the Tl concentration and Tl isotope characteristics of high-pressure metamorphic veins and host eclogites in the Dabie terrane were investigated. The results indicate that phengite controls the overall inventory of Tl in the host eclogites and that the fluids responsible for vein formation were derived from phengite-bearing eclogites. The study also suggests that fluids derived from eclogite dehydration are characterized by higher Cs/Tl ratios compared to their host eclogites. Arc magmas with high Cs/Tl and low Ba/Th ratios likely contain residual phengite at subarc depths.
Article
Geosciences, Multidisciplinary
Chadlin M. Ostrander, Brian Kendall, Gwyneth W. Gordon, Sune G. Nielsen, Wang Zheng, Ariel D. Anbar
Summary: This study presents evidence of molecular oxygen accumulation during the late Archean period, shedding light on the extent and distribution of O-2 at Earth's surface. The findings suggest that O-2 in the atmosphere could have been homogeneously distributed at low levels or accumulated near sites of O-2 production. The penetration of O-2 in marine sediments was minimal, indicating limited burial of manganese oxide minerals.
FRONTIERS IN EARTH SCIENCE
(2022)
Article
Geochemistry & Geophysics
Wanyi Lu, Yi Wang, Delia W. Oppo, Sune G. Nielsen, Kassandra M. Costa
Summary: Oceanic oxygen reconstructions of the last glacial period are crucial for understanding deep ocean carbon storage and validating climate model simulations. Existing reconstructions of bottom-water oxygen (BWO) are ambiguous, and we propose and evaluate three new proxies for BWO.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Geochemistry & Geophysics
Fei Wu, Jeremy D. Owens, Christopher R. German, Rachel A. Mills, Sune G. Nielsen
Summary: This study presents the first investigation of V isotope composition in hydrothermal sediments, revealing significant differences compared to non-hydrothermal sediments and open ocean seawater. The study also establishes a mass balance model that assesses the impact of hydrothermal precipitation on the marine elemental and isotopic budget of V, suggesting that hydrothermal input accounts for -13% of the global marine V input.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2022)
Article
Multidisciplinary Sciences
Stephen P. Hicks, Lidong Bie, Catherine A. Rychert, Nicholas Harmon, Saskia Goes, Andreas Rietbrock, Songqiao Shawn Wei, Jenny S. Collier, Timothy J. Henstock, Lloyd Lynch, Julie Prytulak, Colin G. Macpherson, David Schlaphorst, Jamie J. Wilkinson, Jonathan D. Blundy, George F. Cooper, Richard G. Davy, John -Michael Kendall
Summary: Volatiles expelled from subducted plates affect the melting of the overlying mantle, which is important for arc volcanism. This study examines seismic attenuation beneath the Lesser Antilles arc and reveals the role of expelled fluids and melt in controlling volcanism. The results show that cold boundary layers transport fluids towards the back-arc, while warm mantle beneath the back-arc feeds arc volcanoes.
Article
Geochemistry & Geophysics
Chadlin M. Ostrander, Sune G. Nielsen, Hayley J. Gadol, Luciana Villarroel, Scott D. Wankel, Tristan J. Horner, Jerzy Blusztajn, Colleen M. Hansel
Summary: Thallium (Tl) isotopes serve as a valuable tool for studying the history of molecular oxygen in seawater. Understanding the modern Tl isotope cycle is crucial for its application, especially in anoxic environments. This study found significant variability in Tl isotopes in short timeframes and observed the association of Tl with sulfide and other metals. The sediment data revealed limited isotopic variability, indicating the ability of sediments to capture the Tl isotope composition of contemporary waters.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Multidisciplinary Sciences
M. E. Newcombe, S. G. Nielsen, L. D. Peterson, J. Wang, C. M. O'D Alexander, A. R. Sarafian, K. Shimizu, L. R. Nittler, A. J. Irving
Summary: The timing and types of delivery of volatiles to the terrestrial planets are still debated. This study shows that achondrite meteorites have extremely low water contents, suggesting that differentiated planetesimals degassed efficiently before or during melting. Therefore, substantial amounts of water could only be delivered to Earth through unmelted material.
Article
Geochemistry & Geophysics
Siqi Li, Oliver Friedrich, Sune G. Nielsen, Fei Wu, Jeremy D. Owens
Summary: Oceanic Anoxic Event-2 (OAE-2, -94 Ma ago) was a period of significant perturbation to the carbon and nutrient cycles. Localities experienced heterogeneous redox fluctuations, with some showing persistent anoxic-to-euxinic conditions and others showing short-term hypoxic-to-anoxic oscillations. This study used vanadium isotopes to track these redox fluctuations and identified occasional weak oxygenation under generally anoxic conditions.
EARTH AND PLANETARY SCIENCE LETTERS
(2023)
Article
Geochemistry & Geophysics
Rachel F. Phillips, Yi Wang, Frieder Klein, Gabriela Farfan, Chadlin M. Ostrander, Hayley Gadol, Colleen M. Hansel, Sune G. Nielsen, Dominik Weiss
Summary: Thallium (Tl) isotopes are used to reconstruct changes in global ocean oxygenation by tracking changes in past sedimentary manganese (Mn) oxide burial. Both triclinic birnessite and todorokite exhibit weak Tl sorption with minimal isotopic fractionation. Tl sorption onto Mn oxides and associated isotopic fractionation is strongly controlled by mineralogy.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2023)
Article
Geosciences, Multidisciplinary
Anders Lindskog, Seth A. Young, Chelsie N. Bowman, Nevin P. Kozik, Sean M. Newby, Mats E. Eriksson, Johan Pettersson, Emmy Molin, Jeremy D. Owens
Summary: Marine biodiversity increased significantly during the Ordovician Period. The study of iodine-to-calcium records in marine carbonates from the Baltoscandia region reveals a progressive oxygenation of seafloor environments, with well-oxygenated waters originating from the Iapetus Ocean. The peak dissolved oxygen concentrations coincide with the highest biodiversity increases and ecosystem reorganizations, suggesting that ventilation of shelves played a critical role in regulating early Palaeozoic marine biodiversity.
Article
Geosciences, Multidisciplinary
T. R. Them II, J. D. Owens, S. M. Marroquin, A. H. Caruthers, J. P. Trabucho Alexandre, B. C. Gill
Summary: Many trace metals in the oceans are sensitive to redox reactions, which can be affected during periods of expanded oceanic anoxia and euxinia. Understanding their impact on ecosystem restructuring and potential collapse is important. The study focuses on the trace metal molybdenum (Mo) and its variations during the Early Jurassic Toarcian Oceanic Anoxic Event (T-OAE), showing a significant decline in Mo concentrations during the event. The estimated burial of Mo and organic carbon during the T-OAE suggests extensive euxinic conditions.
Article
Geosciences, Multidisciplinary
Nevin P. Kozik, Benjamin C. Gill, Jeremy D. Owens, Timothy W. Lyons, Seth A. Young
Summary: This study analyzes iodine and sulfur isotope geochemical data from three globally distributed carbonate successions to constrain changes in local and global marine redox conditions during the Late Ordovician. The results suggest that locally anoxic conditions were pervasive on shallow carbonate shelves, while global euxinic conditions decreased. This research provides important constraints on local and global marine redox conditions during the Late Ordovician.
Article
Geochemistry & Geophysics
Xinze Lu, Geoffrey J. Gilleaudeau, Brian Kendall
Summary: The Late Ordovician mass extinction is the first major extinction event in the Phanerozoic, but the reasons for the decline in global biodiversity before the extinction are not well understood.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2024)
Article
Geochemistry & Geophysics
Junyao Kang, Daniel D. Gregory, Benjamin Gill, Shiqiang Huang, Changxin Lai, Zhaoshan Chang, Huan Cui, Ivan Belousov, Shuhai Xiao
Summary: Sedimentary pyrite is an important geological archive, but it can be altered by diagenetic and hydrothermal processes. This study successfully trained machine learning algorithms to distinguish pyrite origins using trace element data. The approach was validated and applied to identify the origins of pyrite in two sedimentary successions in South China.
GEOCHIMICA ET COSMOCHIMICA ACTA
(2024)