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Exceptional mobility of an advancing rhyolitic obsidian flow at Cordón Caulle volcano in Chile
Obsidian lava flows accompanied some of Earth’s most powerful eruptions, yet an active advancing flow field has never been observed. Tuffen et al.present four-dimensional models of the lava flow following the 2011 eruption of Cordón Caulle, Chile, and provide new insights into silicic lava flow dynamics.
- Hugh Tuffen
- , Mike R. James
- & C. Ian Schipper
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| Open AccessRapid regional perturbations to the recent global geomagnetic decay revealed by a new Hawaiian record
The Earth’s geomagnetic field has weakened in recent centuries, leading to calls for historic reconstructions; however, records are sparse and unevenly distributed. de Groot et al.provide a new, high-quality record from Hawaiian lavas, revealing crucial insights into past geomagnetic field fluctuations.
- L. V. de Groot
- , A. J. Biggin
- & E. Herrero-Bervera
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Evidence for the alkaline nature of parental carbonatite melts at Oka complex in Canada
With the exception of one occurrence, carbonatites worldwide are curiously deficient in alkalis. Here, Chen et al.present new melt inclusion data from plutonic relics in Canada that hint at a wider prevalence of alkali-enriched parental carbonatite in the geological record than previously thought.
- Wei Chen
- , Vadim S. Kamenetsky
- & Antonio Simonetti
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Deoxygenation alters bacterial diversity and community composition in the ocean’s largest oxygen minimum zone
Oxygen minimum zones in the global ocean have an important role in biogeochemical cycles, yet their response to climate change is poorly understood. Here, the authors show that bacterial community composition is tightly coupled to dissolved oxygen and is likely to fundamentally change as the oceans warm.
- J. Michael Beman
- & Molly T. Carolan
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| Open AccessNatural gold particles in Eucalyptus leaves and their relevance to exploration for buried gold deposits
The discovery of new gold deposits has declined by 45% over the past 10 years. Lintern et al.present new evidence for the occurrence of particulate gold in trees growing above buried mineral deposits, and propose vegetation sampling as a mineral exploration method.
- Melvyn Lintern
- , Ravi Anand
- & David Paterson
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| Open AccessSequestration of Martian CO2 by mineral carbonation
The mechanism by which Mars lost its early dense and carbon dioxide-rich atmosphere remains relatively unknown. Here, via mineralogical analysis of the Lafayette Martian meteorite, Tomkinson et al. infer that carbonation was an effective carbon dioxide sequestration mechanism on an early, water-rich Mars.
- Tim Tomkinson
- , Martin R. Lee
- & Caroline L. Smith
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Source time function properties indicate a strain drop independent of earthquake depth and magnitude
Earthquakes occur on a broad range of depths and magnitudes, making their origins and impacts difficult to assess. Here, the analysis of 1,700 earthquakes reveals that strain drop is globally invariant, providing constraints on the rupture process and simplifying the task of earthquake damage predictions.
- Martin Vallée
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Earthworms facilitate carbon sequestration through unequal amplification of carbon stabilization compared with mineralization
The presence of earthworms in soil may significantly increase CO2 emissions, but the impacts of earthworms on net carbon sequestration are poorly understood. Zhang et al. introduce a new concept by which the effects of earthworms on the balance of carbon mineralization and stabilization can be quantified.
- Weixin Zhang
- , Paul F. Hendrix
- & Shenglei Fu
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Photochemical reflectance index as an indirect estimator of foliar isoprenoid emissions at the ecosystem level
Isoprene and monoterpenes, emitted by terrestrial plants, have an important role in both plant biology and environment, but they are poorly quantified at the ecosystem level. Peñuelas et al.show that the photochemical reflectance index can be used to indirectly estimate foliar isoprenoid emissions remotely.
- Josep Peñuelas
- , Giovanni Marino
- & Iolanda Filella
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Oxygen consumption rates in subseafloor basaltic crust derived from a reaction transport model
Deep oceanic crust could host a wealth of microbial life, but biogeochemical reactions therein are poorly understood. Orcutt et al.combine measurements of sedimentary oxygen and pore water chemistry from basement crust with a reactive transport box model to shed light on oxygen consumption in basaltic crust.
- Beth N. Orcutt
- , C. Geoffrey Wheat
- & Wolfgang Bach
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Human impacts drive a global topographic signature in tree cover
Humans have greatly altered the distribution of forests across the world. Here, the authors use estimates of tree cover from remote-sensing data to reveal that human impact has produced a strong tendency for forest remnants to persist primarily on sloped terrain.
- Brody Sandel
- & Jens-Christian Svenning
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| Open AccessOsmium isotope evidence for a large Late Triassic impact event
Before the mass extinction that characterized the Late Triassic period, there were a series of biotic turnover events, the cause of which are the subject of debate. Sato et al. present geochemical evidence in support of the theory that extraterrestrial impacts had an important role in these events.
- Honami Sato
- , Tetsuji Onoue
- & Katsuhiko Suzuki
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| Open AccessTime-calibrated Milankovitch cycles for the late Permian
The astronomical time scale is an essential geochronological tool, but is presently limited to the Cenozoic and Mesozoic eras. Here, Wuet al.time-calibrate Milankovitch cycles identified in strata from South China and extend this essential tool into the late Permian.
- Huaichun Wu
- , Shihong Zhang
- & Tianshui Yang
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Oblique subduction modelling indicates along-trench tectonic transport of sediments
Sedimentation along convergent plate margins, the destructive sites of tectonic plate collision, is poorly understood. Malatestaet al.use a cutting-edge three-dimensional subduction model to demonstrate that the trench-parallel motion of sediments has a much more important role than previously thought.
- Cristina Malatesta
- , Taras Gerya
- & Giovanni Capponi
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Carbon precipitation from heavy hydrocarbon fluid in deep planetary interiors
Methane is a major constituent of planetary interiors, yet phase relations in the C–H system are poorly understood. This work documents the chemical reactivity of the C–H system over a wide range of temperatures and pressures, and sheds light on the chemical composition of Earth and icy giants.
- Sergey S. Lobanov
- , Pei-Nan Chen
- & Alexander F. Goncharov
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Pacific deep circulation and ventilation controlled by tidal mixing away from the sea bottom
The global ocean conveyor belt, a key element of climate change, carries heat, carbon and various dissolved materials in the deep ocean. Here, the authors’ ocean model simulations demonstrate that tide-induced mixing away from the sea bottom is driving the Pacific branch of this conveyor belt.
- Akira Oka
- & Yoshihiro Niwa
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| Open AccessNoble metal nanoclusters and nanoparticles precede mineral formation in magmatic sulphide melts
It has long been suggested, but never shown, that nanometre-sized particles precede mineral formation in magmatic systems. Here, Helmyet al.demonstrate that platinum and arsenic self-organize to nanoparticle precursors in magmatic liquids before mineral crystallization.
- Hassan M. Helmy
- , Chris Ballhaus
- & Marian Tredoux
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Siberian larch forests and the ion content of thaw lakes form a geochemically functional entity
Hitherto, Siberian vegetation was not considered to cause the south-to-north ion content gradient of thaw lakes. Herzschuh et al.propose that higher evapotranspiration in larch forests compared with that in the tundra leads to local salt accumulation in permafrost soils, which are transported as solutes to nearby lakes.
- Ulrike Herzschuh
- , Luidmila A. Pestryakova
- & H. John B. Birks
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Estimating the tolerance of species to the effects of global environmental change
Global environmental change is affecting the strength of interspecific interactions. The authors here estimate how much change species can tolerate before becoming extinct, and they find that species tolerance is very sensitive to the net direction of change.
- Serguei Saavedra
- , Rudolf P. Rohr
- & Jordi Bascompte
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Conventional tree height–diameter relationships significantly overestimate aboveground carbon stocks in the Central Congo Basin
Accurate estimates of tropical forest carbon stocks are needed for policies to reduce emissions from loss of forests. By looking at a central area in the Congo Basin, Kearsleyet al.find that inconsistencies in height–diameter relationships across Central Africa cause overestimations between regions.
- Elizabeth Kearsley
- , Thales de Haulleville
- & Hans Verbeeck
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| Open AccessDistinct iron isotopic signatures and supply from marine sediment dissolution
The dissolution of iron from sediments along ocean margins may stimulate photosynthesis and moderate global climate. This study shows how margin sediments supply iron in varying amounts between regions, and by distinct mechanisms, which may be due to geological characteristics and hydrological controls on land.
- William B. Homoky
- , Seth G. John
- & Rachel A. Mills
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Flow velocities of Alaskan glaciers
Alaskan mountain glaciers are losing ice and contribute to sea level rise, but contributions from specific ice-loss mechanisms are not known. Here, calving losses in Central Alaska are found to equal 36% of the net regional mass change each year and regional flux is dictated largely by snow accumulation rates.
- Evan W. Burgess
- , Richard R. Forster
- & Christopher F. Larsen
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Turbulence drives microscale patches of motile phytoplankton
Patchiness in the distribution of phytoplankton promotes many of the ecological interactions that underpin the marine food web. This study shows that turbulence, ubiquitous in the ocean, counter-intuitively ‘unmixes’ a population of motile phytoplankton, generating intense, small-scale patchiness in its distribution.
- William M. Durham
- , Eric Climent
- & Roman Stocker
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| Open AccessThe importance of stress percolation patterns in rocks and other polycrystalline materials
All rocks contain patterns, but how they form is not clear. Here, finite element models are used to show that grain-to-grain variations in elastic moduli cause stress to percolate in polycrystalline materials, causing shear localization and providing a template for foliation development in rocks.
- P.C. Burnley
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| Open AccessMorphology and mixing state of individual freshly emitted wildfire carbonaceous particles
Biomass burning is a major source of carbonaceous particles, including tar balls and soot, that affect earth’s climate. Studying a wildfire plume, this work identifies two types of tar balls and classifies soot according to its mixing state with implications for the calculation of aerosol radiative forcing.
- Swarup China
- , Claudio Mazzoleni
- & Manvendra K. Dubey
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| Open AccessRapid changes in the electrical state of the 1999 Izmit earthquake rupture zone
Low-resistivity crustal fluids occur near fault zones, but their relation to earthquake generation is unclear. Here, electromagnetic data from the Izmit earthquake reflects the pressure-induced transition between isolated and interconnected fluids that is linked to foreshocks before large earthquakes.
- Yoshimori Honkura
- , Naoto Oshiman
- & Elif Tolak Çiftçi
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Fossilized iron bacteria reveal a pathway to the biological origin of banded iron formation
Debates on the formation of banded iron formations (BIFs) in ancient iron-rich oceans are dominated by contradictions between biological and non-biological iron cycling. This study provides environmental evidence that directly implicates photosynthetic iron-oxidizing microorganisms in vast-scale BIF deposition.
- Ernest Chi Fru
- , Magnus Ivarsson
- & Marco Stampanoni
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Upper mantle viscosity and dynamic subsidence of curved continental margins
The evolution of continental rifting curvature can be studied using thermal convection models. Studying how this curvature controls the subsidence of offshore basins, Sacek and Ussami find that the mantle viscosity structure affects the subsidence rate and evolution of sedimentary basins along curved margins.
- Victor Sacek
- & Naomi Ussami
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An earthquake gap south of Istanbul
The North Anatolian Fault Zone in Turkey has produced many large earthquakes, however the Marmara region has been inactive and is facing a high probability for a large earthquake. Here, Bohnhoff et al. report on a large seismicity gap in this area with implications for a seismic hazard for Istanbul.
- Marco Bohnhoff
- , Fatih Bulut
- & Mustafa Aktar
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| Open AccessCarbon dioxide concentration dictates alternative methanogenic pathways in oil reservoirs
Deep subsurface formations are potential sites for carbon capture and storage but how subsurface microbial communities may respond to this is not clear. Here, Mayumi et al. construct microcosms and show that increasing CO2partial pressure via carbon capture and storage more than doubles the rate of methanogenesis.
- Daisuke Mayumi
- , Jan Dolfing
- & Yoichi Kamagata
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Role of biogenic silica in the removal of iron from the Antarctic seas
Iron plays a key role in controlling biological production in the Southern Ocean, yet mechanisms regulating iron availability are not completely understood. Here, Ingall et al.show that structural incorporation of reduced, organic iron into biogenic silica represents a new and substantial removal pathway.
- Ellery D. Ingall
- , Julia M. Diaz
- & Jay A. Brandes
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| Open AccessHuman deforestation outweighs future climate change impacts of sedimentation on coral reefs
Forest cover up-river influences the sediments reaching coral reefs, but how this relationship is affected by future climate change is not clear. In a study of the Malagasy coral reefs, Maina et al.find that regional land-use management is more important than mediating climate change for reducing reef sedimentation.
- Joseph Maina
- , Hans de Moel
- & Jan E. Vermaat
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Inferred time- and temperature-dependent cation ordering in natural titanomagnetites
Cation ordering in cubic-structured oxides can strongly affect magnetic properties. Here, the authors show that in some natural titanomagnetites, large and reversible changes in Curie temperature result from annealing at moderate temperatures (350–400 °C), most likely arising from changes in cation ordering.
- Julie A. Bowles
- , Mike J. Jackson
- & Jeffrey S. Gee
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A new Late Triasssic phytogeographical scenario in westernmost Gondwana
In the Late Triassic, southern Gondwanan flora is thought to have been dominated by endemic species mainly restricted to eastern areas with some mixing with northern species. In this study, pollen and spore assemblages from Argentina reveal the presence of these mixed flora in the westernmost Gondwana as well.
- Silvia N Césari
- & Carina E Colombi
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| Open AccessDevelopment of Middle Stone Age innovation linked to rapid climate change
The South African archaeological record contains evidence of the early flourishing of the human mind. Ziegler et al. provide new paleoclimate reconstructions, which suggest that rapid fluctuations in global climate have played a key role in the evolution of these early human cultures.
- Martin Ziegler
- , Margit H. Simon
- & Rainer Zahn
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Pyroclastic passage zones in glaciovolcanic sequences
Subglacial volcanoes host passage zones that can be used to define high stands of englacial lakes and paleo-ice thickness. This study identifies a pyroclastic passage zone in a subglacial volcano, which may help calculate transient paleolake levels and improve estimates of paleo-ice thickness.
- James K. Russell
- , Benjamin R. Edwards
- & Lucy A. Porritt
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Discovery of seifertite in a shocked lunar meteorite
Few high-pressure polymorphs have been found from lunar meteorites even though the moon has experienced heavy meteorite bombardment. This study presents evidence of a high-pressure polymorph of silica—seifertite—from a lunar meteorite; a record of an intense planetary collision on the moon ~2.7 Ga ago.
- Masaaki Miyahara
- , Shohei Kaneko
- & Naohisa Hirao
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Biological carbon precursor to diagenetic siderite with spherical structures in iron formations
The role of bacteria in the origin of iron formations (IF) remains unclear because no direct evidence for their involvement exists. This study shows that spherical siderite in deep-water IF represents a biosignature for photoferrotrophy, whereas massive siderite reflects high cyanobacterial biomass in shallow-water.
- Inga Köhler
- , Kurt O Konhauser
- & Andreas Kappler
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Another rapid event in the carbon-14 content of tree rings
A strong increase in atmospheric 14C was measured in tree rings at AD 774 to 775, providing potential evidence of large cosmic ray fluxes to Earth, but the cause of this event is unclear. Here, Miyake et al. report a second 14C event in AD 993, which suggests that the most likely cause was a large solar proton event.
- Fusa Miyake
- , Kimiaki Masuda
- & Toshio Nakamura
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Louisville seamount subduction and its implication on mantle flow beneath the central Tonga–Kermadec arc
Seamounts that have subducted beneath a mantle wedge allow the study of trace element recycling and mantle flow in subduction zones. Here, a geochemical analysis of central Tonga–Kermadec arc lavas suggests primarily trench-normal mantle flow in the mantle wedge beneath the central Tonga–Kermadec arc.
- Christian Timm
- , Daniel Bassett
- & Anthony B. Watts
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| Open AccessInitialized near-term regional climate change prediction
Near-term climate prediction is an information tool used in climate adaptation services. This study analyses the quality of the predictions, showing that near-term climate forecasts have good skill in predicting temperature at regional scales, where most of the skill is attributed to atmospheric composition changes.
- F. J. Doblas-Reyes
- , I. Andreu-Burillo
- & G. J. van Oldenborgh
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| Open AccessOcean lead at the termination of the Younger Dryas cold spell
The abrupt ending of the Younger Dryas cooling episode marked the onset of the present interglacial and was the most prominent climate change in the Earth’s recent history. This study shows evidence for a sequence of events with a leading role of the ocean at the transition into the present day warm Holocene epoch.
- Christof Pearce
- , Marit-Solveig Seidenkrantz
- & Søren M. Kristiansen
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Early Cretaceous chalks from the North Sea giving evidence for global change
Calcareous nannofossils were important marine primary producers in Jurassic and Cretaceous oceans at low latitudes. Here, North Sea sediment records reveal that favourable conditions for nannoconids existed also at high latitudes, and nannoconids faced global decline at the onset of greenhouse conditions.
- Jörg Mutterlose
- & Cinzia Bottini
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Seismic detection of increased degassing before Kīlauea's 2008 summit explosion
The onset of the ongoing summit eruption at Kilauea Volcano was associated with changes in seismic anisotropy and increased gas flux. This study shows that seismic anisotropy variations are also a function of alterations in stress conditions, and provides a new method for tracking gas flux using seismic observations.
- Jessica H. Johnson
- & Michael P. Poland
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Reconciliation of marine and terrestrial carbon isotope excursions based on changing atmospheric CO2 levels
Carbon isotope excursions (CIEs) measured in marine and terrestrial substrates indicate large-scale changes in the global carbon cycle. Schubert and Jahren show that larger-amplitude CIEs measured in terrestrial substrates reflect increased carbon isotope fractionation by land plants under elevated atmospheric CO2.
- Brian A. Schubert
- & A. Hope Jahren
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| Open AccessObservations from old forests underestimate climate change effects on tree mortality
It is thought that only climate change drives temporal tree mortality increases in old forests. Here, Luo and Chen show that both forest dynamics and climate change drive temporal tree mortality increases in young and old forests, and that climate change-associated mortality increases are higher in the young forests.
- Yong Luo
- & Han Y. H. Chen
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Nitrogen cycle feedbacks as a control on euxinia in the mid-Proterozoic ocean
Clear evidence between sulphidic conditions and denitrification in the Proterozoic ocean should be observable in the rock record. Here, minimalistic biogeochemical modelling shows how periods of extensive sulphate reduction must have gone hand-in-hand with low denitrification and available nitrate.
- R.A. Boyle
- , J.R. Clark
- & T.M. Lenton
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| Open AccessIncreased ventilation of Antarctic deep water during the warm mid-Pliocene
It is thought that during the mid-Pliocene warm period the Atlantic Meridional Overturning Circulation (AMOC) must have been stronger than today. Here, using proxy data compilation and simulation, Zhang et al.show that the two observations used to support stronger AMOC may not necessitate its increased strength.
- Zhongshi Zhang
- , Kerim H. Nisancioglu
- & Ulysses S. Ninnemann
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| Open AccessSolar wind entry into the high-latitude terrestrial magnetosphere during geomagnetically quiet times
A full understanding of the penetration of solar wind plasma into the Earth’s magnetosphere, during geomagnetically quiet times, remains elusive. Using multi-spacecraft data, Shi et al.find unexpected entry of the solar wind into the high-latitude magnetosphere and suggest a probable entry mechanism.
- Q.Q. Shi
- , Q.-G. Zong
- & E. Lucek