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| Open AccessSynchronizing rock clocks in the late Cambrian
The Cambrian is the most poorly dated period of the past 541 million years. Here, the authors present a new astronomical time scale, allowing for a first assessment, in numerical time, of the evolution of major biotic and abiotic changes that characterized the late Cambrian Earth.
- Zhengfu Zhao
- , Nicolas R. Thibault
- & Arne T. Nielsen
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Article
| Open AccessSuper-hydration and reduction of manganese oxide minerals at shallow terrestrial depths
The enigmatic relationship of birnessite and buserite, the two most representative phases in submarine nodules, has been established to reveal that buserite is a super-hydrated form of birnessite, forming at shallow terrestrial depth in the presence of water
- Seohee Yun
- , Huijeong Hwang
- & Yongjae Lee
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Article
| Open AccessCarbonate complexation enhances hydrothermal transport of rare earth elements in alkaline fluids
In-situ X-ray measurements reveal that the formation of rare earth-carbonate complexes in high-temperature alkaline fluids may facilitate their hydrothermal mobilization and contribute to their economic concentration in carbonatitic systems.
- Marion Louvel
- , Barbara Etschmann
- & Joël Brugger
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Article
| Open AccessMercury evidence for combustion of organic-rich sediments during the end-Triassic crisis
Mercury (Hg) concentrations and isotopes from a deep-ocean Triassic–Jurassic (~201 Ma) boundary section provide evidence of large inputs from terrestrial organic-rich sources through combustion by magmatic sills and wildfires.
- Jun Shen
- , Runsheng Yin
- & Shane D. Schoepfer
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Article
| Open AccessSuperlinear scaling of riverine biogeochemical function with watershed size
River networks play an important role in biogeochemical processes of the earth system. Here the authors show that cumulative river network function increases faster than watershed size for many biogeochemical processes, particularly at higher river flow, indicating large rivers contribute disproportionately to network function in the Earth System.
- Wilfred M. Wollheim
- , Tamara K. Harms
- & Jacques C. Finlay
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| Open AccessBoron isotopes in boninites document rapid changes in slab inputs during subduction initiation
The geochemical record of subduction initiation is still not well understood, despite >50 years of study. Here, the authors use boron isotopes in Izu-Bonin boninites to document rapid changes in slab inputs to melting at the start of subduction, related to the steepening and cooling of the downgoing Pacific plate.
- Hong-Yan Li
- , Xiang Li
- & Yi-Gang Xu
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Article
| Open AccessEvidence for the oxidation of Earth’s crust from the evolution of manganese minerals
The co-evolution of oxygenation of the Earth’s atmosphere and lithosphere is still poorly constrained. However, the oxidation state of manganese minerals reveals that the redox state of Earth’s crust responds to changes in atmospheric oxygen following a ~66 million-year time lag.
- Daniel R. Hummer
- , Joshua J. Golden
- & Robert M. Hazen
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Article
| Open AccessMantle Hg isotopic heterogeneity and evidence of oceanic Hg recycling into the mantle
This work demonstrates distinct mass-independent mercury isotope fractionation in global basalts, which suggests mantle Hg isotope heterogeneity and reveals large-scale translithospheric Hg recycling via plate tectonics.
- Runsheng Yin
- , Di Chen
- & Bernd Lehmann
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Article
| Open AccessExogenic origin for the volatiles sampled by the Lunar CRater Observation and Sensing Satellite impact
The water and other volatiles observed in the LCROSS impact plume contained too much nitrogen to have originated from volcanic outgassing. These volatiles, stored in the top 1-3 meters of the Cabeus permanently shaded region, were delivered by comet impacts.
- K. E. Mandt
- , O. Mousis
- & A. Luspay-Kuti
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Article
| Open AccessCatastrophic slab loss in southwestern Pangea preserved in the mantle and igneous record
The origin of the Permian-Triassic Choiyoi silicic large igneous province (SLIP) is assessed by linking the igneous record, plate-kinematic reconstructions, and the deep mantle. This study suggests an origin related to a massive slab loss in Pangea.
- Guido M. Gianni
- & César R. Navarrete
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Article
| Open AccessStratification in planetary cores by liquid immiscibility in Fe-S-H
Yokoo et al. find the liquid immiscibility between H-rich and S-rich liquids Fe above 20 GPa. The separation of immiscible liquids could explain the disappearance of Mars’ magnetic field and the formation of low-velocity layer atop the Earth’s core.
- Shunpei Yokoo
- , Kei Hirose
- & Yasuo Ohishi
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Article
| Open AccessInner core composition paradox revealed by sound velocities of Fe and Fe-Si alloy
The origin of the observed low shear wave velocity in the solid inner core is unclear. Here, the authors report shear wave velocities of iron and iron-silicon alloy under Earth’s core conditions by shock compression and find that neither the effect of temperature nor incorporation of Si can explain observed low shear wave velocity in the inner core.
- Haijun Huang
- , Lili Fan
- & Yingwei Fei
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Article
| Open AccessMagnetite layer formation in the Bushveld Complex of South Africa
The Main Magnetite Layer of the Bushveld Complex of South Africa is an economically important deposit of Fe, Ti and V but its mode of formation is enigmatic. Models of fractional crystallization and reactive transport show that it probably accumulated as a loose mush and subsequently was compacted rather than forming in situ.
- Zhuosen Yao
- & James E. Mungall
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Article
| Open AccessDecoupling of inorganic and organic carbon during slab mantle devolatilisation
Hydrated mantle rocks store a significant amount of organic and inorganic carbon, impacting the geological cycle. During subduction the carbonate return to the upper plate while organic carbon remains trapped to be recycled in the deep earth.
- P. Bouilhol
- , B. Debret
- & K. W. Burton
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Article
| Open AccessExtensive primary production promoted the recovery of the Ediacaran Shuram excursion
Variable dominance of distinct microbial communities during the late Ediacaran, recorded in C and N cycles perturbations and in Raman structural heterogeneities of organic matter, modulated the recovery from the most negative δ13Ccarb excursion in Earth’s history.
- Fuencisla Cañadas
- , Dominic Papineau
- & Chao Li
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Article
| Open AccessDecreasing extents of Archean serpentinization contributed to the rise of an oxidized atmosphere
Throughout the Archean, H2 generation via low-temperature ultramafic serpentinization likely helped prevent atmospheric O2 accumulation and continued until the abundance of ultramafic rocks diminished setting the stage for the Great Oxidation Event.
- James Andrew M. Leong
- , Tucker Ely
- & Everett L. Shock
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Comment
| Open AccessA lunar sample renaissance
Though the lunar samples returned by the Apollo and Luna missions have been studied for more than 50 years, scientists are discovering new clues into the early evolution of the Moon by looking through the lens of modern analytical techniques.
- Tabb C. Prissel
- & Kelsey B. Prissel
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Article
| Open AccessPhase transitions in natural C-O-H-N-S fluid inclusions - implications for gas mixtures and the behavior of solid H2S at low temperatures
Different structures and solid states of H2S at low temperatures, pertaining to extraterrestrial environments, were measured in natural, mineral-hosted, micro-scale fluid inclusions containing complex CH4-H2S-CO2-N2 gas mixtures.
- Marta Sośnicka
- & Volker Lüders
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Article
| Open AccessThermochemical anomalies in the upper mantle control Gakkel Ridge accretion
The ultimate driver of ultraslow spreading ridges is unknown. Here the authors use spreading rates derived directly from isotopic ages of seafloor samples to link magmatic and amagmatic segments with thermochemical variations in the upper mantle.
- John M. O’Connor
- , Wilfried Jokat
- & Anthony A. P. Koppers
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Article
| Open AccessFluids as primary carriers of sulphur and copper in magmatic assimilation
Experiments show that when magma heats black shale wall-rock, fluids form and mobilize S and Cu, which can then concentrate and form base metal deposits. The fluids also attach to sulphide droplets and cause them to float in the host silicate melt.
- Ville J. Virtanen
- , Jussi S. Heinonen
- & Karina Moslova
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| Open AccessRapid oxygen exchange between hematite and water vapor
Knowing how individual water molecules interact with surfaces is crucial for understanding surface and interface phenomena. Here, the authors show how local water-water interactions enable an unforeseen and surprisingly rapid mechanism of atom exchange between a common mineral and its surroundings.
- Zdenek Jakub
- , Matthias Meier
- & Gareth S. Parkinson
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| Open AccessIn-situ abiogenic methane synthesis from diamond and graphite under geologically relevant conditions
Using diamond anvil cell and high temperature experiments, this work proves that the interaction between deep hydrogen rich fluids and reduced carbon minerals may be an efficient mechanism for producing abiotic hydrocarbons at the upper mantle’s pressures and temperatures.
- Miriam Peña-Alvarez
- , Alberto Vitale Brovarone
- & Eugene Gregoryanz
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| Open AccessPolluted white dwarfs reveal exotic mantle rock types on exoplanets in our solar neighborhood
While some exoplanets that once orbited Polluted white dwarfs are similar to Earth, most appear to have rock types that are exotic to our Solar System. We thus develop a new classification scheme to describe these new and novel lithologies that appear to be dominant among polluted white dwarfs.
- Keith D. Putirka
- & Siyi Xu
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| Open AccessLight oxygen isotopes in mantle-derived magmas reflect assimilation of sub-continental lithospheric mantle material
Isotopically light oxygen in mantle derived magmas is generally attributed to the occurrence of deeply subducted crustal material in the mantle. New analyses of olivine in kimberlites worldwide suggest that assimilation of lithospheric mantle during magma ascent is the source of isotopically light oxygen in these, and, potentially other continental magmas.
- Jing-Yao Xu
- , Andrea Giuliani
- & William L. Griffin
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Article
| Open AccessVolumetric extrusive rates of silicic supereruptions from the Afro-Arabian large igneous province
Quantifying the tempo of large-volume silicic magma generation and eruption is a long-standing but elusive task. Here we show that the three largest sequentially dated eruptions, totaling >4,300 km3, occurred within 48 ± 34 kyr and yield the highest known long term volumetric extrusive rate of silicic volcanism on Earth.
- Jennifer E. Thines
- , Ingrid A. Ukstins
- & Mark Schmitz
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| Open AccessAssessing the importance of thermogenic degassing from the Karoo Large Igneous Province (LIP) in driving Toarcian carbon cycle perturbations
The emplacement of the Karoo LIP occurred synchronously with the Toarcian crisis, which is characterized by negative carbon isotope excursions. Here the authors use carbon cycle modelling to show that thermogenic carbon released during LIP emplacement represents a plausible source for the negative excursions.
- Thea H. Heimdal
- , Yves Goddéris
- & Henrik H. Svensen
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| Open AccessAlpine-style nappes thrust over ancient North China continental margin demonstrate large Archean horizontal plate motions
How far back in time plate tectonics operated on Earth is debated because of a paucity of geological evidence for horizontal plate motions. Here the authors show that plates moved laterally by >3500 kilometres 2.7–2.5 billion years ago, demonstrating plate tectonics in the Archean Eon, when life developed on Earth.
- Yating Zhong
- , Timothy Kusky
- & Hao Deng
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Article
| Open AccessMolybdenum isotopes unmask slab dehydration and melting beneath the Mariana arc
How the subducted oceanic lithosphere provides fluids and melts to flux the subarc mantle source of arc magmas is controversial. Here the authors use Mo and other isotopes to show serpentinites formed in both the forearc mantle and the subducted lithosphere contribute to generating arc magmas.
- Hong-Yan Li
- , Rui-Peng Zhao
- & Yi-Gang Xu
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Article
| Open AccessBreaking of Henry’s law for sulfide liquid–basaltic melt partitioning of Pt and Pd
Platinum group elements are used as tracers for planetary and PGE sulfide deposit formation. Here, the authors, through the measurements of Pt and Pd partition coefficients between sulfide liquid and basaltic melt, demonstrate that the partitioning of Pt and Pd does not obey Henry’s law.
- Mingdong Zhang
- & Yuan Li
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Article
| Open AccessGlobal syndromes induced by changes in solutes of the world’s large rivers
Rivers are increasingly plagued by “syndromes”, i.e. salinization, mineralization, desalinization, acidification, alkalization, hardening and softening. A global look at river biogeochemistry reveals dramatically increased flux estimates and anthropogenic drivers of syndromes.
- Jiang Wu
- , Nan Xu
- & Jinren Ni
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| Open AccessSeismological expression of the iron spin crossover in ferropericlase in the Earth’s lower mantle
This study identifies the predicted seismic expression of the high-to-low iron spin crossover in the deep Earth mineral ferropericlase. A depth-dependent signal is detected in the fastest and slowest regions, related to lateral temperature variations, of several global seismic tomography models.
- Grace E. Shephard
- , Christine Houser
- & Renata M. Wentzcovitch
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Article
| Open AccessIsotopic evolution of planetary crusts by hypervelocity impacts evidenced by Fe in microtektites
Fe isotopic composition of the distal ejecta of a terrestrial impact crater records both evaporation and condensation, refining the nature of the isotopic fractionation taking place during hypervelocity impacts in the Solar System.
- S. M. Chernonozhkin
- , C. González de Vega
- & S. Goderis
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Article
| Open AccessMassive methane fluxing from magma–sediment interaction in the end-Triassic Central Atlantic Magmatic Province
Global climate changes triggered by massive output of greenhouse gases led to mass extinctions in Earth’s past. Here, the authors show that widespread release of methane at the time of the end-Triassic mass extinction was caused by interaction of a Large Igneous Province with sedimentary host-rocks.
- Manfredo Capriolo
- , Andrea Marzoli
- & Csaba Szabó
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| Open AccessLethal microbial blooms delayed freshwater ecosystem recovery following the end-Permian extinction
Harmful algal and bacterial blooms are increasingly frequent in lakes and rivers. From the Sydney Basin, Australia, this study uses fossil, sedimentary and geochemical data to reveal bloom events following forest ecosystem collapse during the end-Permian event and that blooms have consistently followed warming-related extinction events, inhibiting the recovery of freshwater ecosystems for millennia.
- Chris Mays
- , Stephen McLoughlin
- & Vivi Vajda
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| Open AccessMixing between chemically variable primitive basalts creates and modifies crystal cargoes
Chemically variable primitive basalts undergo mixing during ascent from the mantle. Here the authors show observations from magma–magma reaction experiments which demonstrate how isothermal mixing between chemically variable basalts creates and modifies crystal cargoes erupted in oceanic settings.
- David A. Neave
- , Philipp Beckmann
- & François Holtz
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| Open AccessOlivine-rich achondrites from Vesta and the missing mantle problem
Ultramafic olivine-rich achondrites provide insight into the missing mantle problem in the asteroid belt. The petrology and geochemistry of these samples suggests they are related to Vesta or the Vestoids.
- Zoltan Vaci
- , James M. D. Day
- & Andreas Pack
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| Open AccessPaleocene/Eocene carbon feedbacks triggered by volcanic activity
The Paleocene–Eocene boundary coincided with runaway global warming possibly analogous to future climate change, but the sources of greenhouse gasses have remained unresolved. Here, the authors reveal volcanism triggered initial warming, and subsequent carbon was released after crossing a tipping point.
- Sev Kender
- , Kara Bogus
- & Melanie J. Leng
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Article
| Open AccessMethane from microbial hydrogenolysis of sediment organic matter before the Great Oxidation Event
Microbial CH4 kept the early Earth warm under the faint young sun, but clear records are lacking. Here the authors present isotopic evidence that CH4 seepage in the Canadian shield is from hydrogen biodegradation in a Neoarchean ecosystem rather than an abiotic synthesis product.
- Xinyu Xia
- & Yongli Gao
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Article
| Open AccessEpisodic construction of the early Andean Cordillera unravelled by zircon petrochronology
Episodic magmatism of the early Andes is the result of a complex interplay between mantle, crust, slab and sediment contributions that can be traced using zircon chemistry. An external (tectonic) model is argued for the episodic plutonism in this extensional continental arc.
- José Joaquín Jara
- , Fernando Barra
- & Diego Morata
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Article
| Open AccessA subduction influence on ocean ridge basalts outside the Pacific subduction shield
We discover a pervasive subduction influence in the Arctic, Atlantic and Indian mantle, which is nearly absent in the Pacific mantle. Such a hemispheric-scale upper mantle heterogeneity reflects the control of a “subduction shield” that has surrounded the Pacific Ocean for 180 Myr.
- A. Y. Yang
- , C. H. Langmuir
- & Z. Chen
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Article
| Open AccessTiming the evolution of antioxidant enzymes in cyanobacteria
How early photosynthesizers managed oxidative stress remains relatively unresolved. Analyses of enzymes dealing with reactive oxygen species traces the evolutionary history of superoxide dismutases and finds evidence of CuZnSOD in the ancestor of all cyanobacteria, dating back to the Archaean.
- Joanne S. Boden
- , Kurt O. Konhauser
- & Patricia Sánchez-Baracaldo
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Perspective
| Open AccessThe search for lunar mantle rocks exposed on the surface of the Moon
Vast, ancient impact basins scattered mantle materials across the lunar surface. We review lunar evolution models to identify candidate mantle lithologies, then assess orbital observations to evalutae the current distribution of these materials and implications for fundamental planetary processes.
- Daniel P. Moriarty III
- , Nick Dygert
- & Noah E. Petro
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Article
| Open AccessKinetically driven successive sodic and potassic alteration of feldspar
This paper reveals that potassic alteration can be triggered by Na-rich fluids, indicating that pervasive sequential sodic and potassic alterations associated with mineralization in some of the world’s largest ore deposits may not necessarily reflect externally-driven changes in fluid alkali contents.
- Gan Duan
- , Rahul Ram
- & Joël Brugger
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Article
| Open AccessOrganic additive release from plastic to seawater is lower under deep-sea conditions
Plastics are major marine pollutants, and while research suggests that they can release potential harmful additives into seawater, how environmental conditions influence this is unknown. Here the authors determine that byproducts released from microplastics are less under deep-sea conditions versus surface.
- Vincent Fauvelle
- , Marc Garel
- & Richard Sempéré
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Article
| Open AccessDeep carbon cycle constrained by carbonate solubility
Carbonate mineral aqueous solubility decreases as carbonates become more Mg-rich during subduction. Coupled with regional variations in amounts of carbon and water subducted, this explains discrepancies in estimates of carbon recycling, suggesting that only around a third returns to the surface.
- Stefan Farsang
- , Marion Louvel
- & Simon A. T. Redfern
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Article
| Open AccessLinking deeply-sourced volatile emissions to plateau growth dynamics in southeastern Tibetan Plateau
Deeply-sourced volatiles are releasing from orogenic plateau regions, providing windows to plateau growth dynamics occurring at variable depths. Here the authors show that mantle-derived volatiles reveal the involvement of mantle dynamics in southeastward growth of the Tibetan Plateau.
- Maoliang Zhang
- , Zhengfu Guo
- & Ying Li
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Article
| Open AccessFingerprinting the Cretaceous-Paleogene boundary impact with Zn isotopes
Elevated Zn isotope compositions occur in K-Pg sedimentary layers of three different depositional environments across North America and the Caribbean. The data indicate a volatilization event, and act as a robust mechanistic indicator of the meteorite impact at the end of the Cretaceous.
- Ryan Mathur
- , Brandon Mahan
- & Francisca E. Oboh-Ikuenobe
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Article
| Open AccessLiquid flow reversibly creates a macroscopic surface charge gradient
Reactions at the interface between mineral surfaces and flowing liquids are ubiquitous in nature. Here the authors explore, using surface-specific sum frequency generation spectroscopy and numeric calculations, how the liquid flow affects the charging and dissolution rates leading to flow-dependent charge gradients along the surface.
- Patrick Ober
- , Willem Q. Boon
- & Mischa Bonn
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Article
| Open AccessOut-of-sequence skeletal growth causing oscillatory zoning in arc olivines
Arc olivines are commonly explained through a paradigm of core-to-rim sequential growth and oscillatory zoning is interpreted to represent magma mixing. Here the authors show Fo–Ni–P oscillatory zoned olivines can grow as out-of-sequence crystal frames and complex zoning can occur in closed systems.
- Pablo Salas
- , Philipp Ruprecht
- & Osvaldo Rabbia