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Recent Publications

  • Abstract Summary:

    Impactors striking the Moon since the formation of its crust have left an indelible imprint on the lunar surface, in the guise of craters and associated impact rocks. The lunar crust has low intrinsic abundances of the highly siderophile elements (HSE: Re, Os, Ir, Ru, Pt, Rh, Pd, Au), at greater than 3000 times lower than in chondrite meteorites. Consequently, during impact, bolides with chondritic or differentiated iron-rich compositions...

  • Barnes J.J, McCubbin F.M, Santos A.R, Day JMD, Boyce J.W, Schwenzer S.P, Ott U., Franchi I.A, Messenger S., Anand M. et al..  2020.  Multiple early-formed water reservoirs in the interior of Mars.
    Abstract Summary:

    Mars's mantle is chemically heterogeneous and contains multiple primordial water reservoirs, according to an analysis of the hydrogen isotopic composition of minerals in Martian meteorites. The abundance and distribution of water within Mars through time plays a fundamental role in constraining its geological evolution and habitability. The isotopic composition of Martian hydrogen provides insights into the interplay between different water...

  • Abstract Summary:

    The Gulf of Papua inner mid-shelf clinothem and lowstand deposits in Pandora Trough record sediment source and routing through the last sea-level cycle on 20 kyr cycles. Clay mineralogy tracked dispersal of sediment from the two types of rivers (wide versus narrow floodplains) to constrain the contributions of river systems to the Gulf of Papua clinothem and Pandora Trough deposits. Fly River sediment has higher illite:smectite than clays...

  • Dillon E.M, Lafferty K.D, McCauley D.J, Bradley D., Norris RD, Caselle JE, DiRenzo G.V, Gardner J.PA, O'Dea A..  2020.  Dermal denticle assemblages in coral reef sediments correlate with conventional shark surveys. 11:362-375.
    Abstract Summary:

    It is challenging to assess long-term trends in mobile, long-lived and relatively rare species such as sharks. Despite ongoing declines in many coastal shark populations, conventional surveys might be too fleeting and too recent to describe population trends over decades to millennia. Placing recent shark declines into historical context should improve management efforts as well as our understanding of past ecosystem dynamics. A new...

  • Karion A., Callahan W., Stock M., Prinzivalli S., Verhulst K.R, Kim J., Salameh PK, Lopez-Coto I., Whetstone J..  2020.  Greenhouse gas observations from the Northeast Corridor tower network. 12:699-717.
    Abstract Summary:

    We present the organization, structure, instrumentation, and measurements of the Northeast Corridor greenhouse gas observation network. This network of tower-based in situ carbon dioxide and methane observation stations was established in 2015 with the goal of quantifying emissions of these gases in urban areas in the northeastern United States. A specific focus of the network is the cities of Baltimore, MD, and Washington, DC, USA, with a...

  • Kadoya S., Catling D.C, Nicklas R.W, Puchtel I.S, Anbar A.D.  2020.  Mantle cooling causes more reducing volcanic gases and gradual reduction of the atmosphere. 13:25-29.
    Abstract Summary:

    The early atmosphere contained negligible O-2 until the Great Oxidation Event (GOE) around 2.4 Ga, but evidence suggests that production of photosynthetic O-2 began hundreds of millions of years earlier. Thus, an ongoing debate concerns the trigger of the GOE. One possibility is that volcanic gases became more oxidising over time. Secular cooling of the mantle affects thermodynamic equilibria and also changes the proportions of reduced and...

  • Barnes JJ, McCubbin FM, Santos AR, Day JMD, Boyce JW, Schwenzer SP, Ott U, Franchi IA, Messenger S, Anand M et al..  2020.  Multiple early-formed water reservoirs in the interior of Mars.
    Abstract Summary:

    The abundance and distribution of water within Mars through time plays a fundamental role in constraining its geological evolution and habitability. The isotopic composition of Martian hydrogen provides insights into the interplay between different water reservoirs on Mars. However, D/H (deuterium/hydrogen) ratios of Martian rocks and of the Martian atmosphere span a wide range of values. This has complicated identification of distinct water...

  • Dee S.G, Cobb KM, Emile-Geay J., Ault T.R, Edwards RL, Cheng H, Charles CD.  2020.  No consistent ENSO response to volcanic forcing over the last millennium. 367:1477-+.
    Abstract Summary:

    The El Nino-Southern Oscillation (ENSO) shapes global climate patterns yet its sensitivity to external climate forcing remains uncertain. Modeling studies suggest that ENSO is sensitive to sulfate aerosol forcing associated with explosive volcanism but observational support for this effect remains ambiguous. Here, we used absolutely dated fossil corals from the central tropical Pacific to gauge ENSO's response to large volcanic eruptions of...

  • Sibert E.C, Zill M.E, Frigyik E.T, Norris RD.  2020.  No state change in pelagic fish production and biodiversity during the Eocene-Oligocene transition. 13:238-+.
    Abstract Summary:

    The Eocene/Oligocene (E/O) boundary (~33.9 million years ago) has been described as a state change in the Earth system marked by the permanent glaciation of Antarctica and a proposed increase in oceanic productivity. Here we quantified the response of fish production and biodiversity to this event using microfossil fish teeth (ichthyoliths) in seven deep-sea sediment cores from around the world. Ichthyolith accumulation rate (a proxy for fish...

  • Abstract Summary:

    The Inner California Borderlands is a complex margin where sediment delivery to the basin floor is largely routed through canyon-channel-gully systems. Using nested geophysical surveys, piston and gravity cores from the Eastern Gulf of Santa Catalina, this study compares two canyon systems and investigates how tectonics, shelf width, gradient, and autogenic processes influence turbidite emplacement timing and grain size. One end-member canyon...

  • Zhang Y.X, Soerensen A.L, Schartup A.T, Sunderland E.M.  2020.  A global model for methylmercury formation and uptake at the base of marine food webs. 34
    Abstract Summary:

    Monomethylmercury (CH3Hg) is the only form of mercury (Hg) known to biomagnify in food webs. Here we investigate factors driving methylated mercury [MeHg = CH3Hg + (CH3)(2)Hg)] production and degradation across the global ocean and uptake and trophic transfer at the base of marine food webs. We develop a new global 3-D simulation of MeHg in seawater and phyto/zooplankton within the Massachusetts Institute of Technology general circulation...

  • Abstract Summary:

    Isotopic compositions of reservoirs in the Moon can be constrained from analysis of rocks generated during lunar magmatic differentiation. Mare basalts sample the largest lunar mantle volume, from olivine- and pyroxene-rich cumulates, whereas ferroan anorthosites and magnesian-suite rocks represent early crustal materials. Incompatible element enriched rocks, known as 'KREEP,' probably preserve evidence for the last highly differentiated...

  • Dyonisius M.N, Petrenko VV, Smith A.M, Hua Q., Yang B, Schmitt J., Beck J., Seth B., Bock M., Hmiel B. et al..  2020.  Old carbon reservoirs were not important in the deglacial methane budget. 367:907-+.
    Abstract Summary:

    Permafrost and methane hydrates are large, climate-sensitive old carbon reservoirs that have the potential to emit large quantities of methane, a potent greenhouse gas, as the Earth continues to warm. We present ice core isotopic measurements of methane (Delta C-14, delta C-13, and delta D) from the last deglaciation, which is a partial analog for modern warming. Our results show that methane emissions from old carbon reservoirs in response...

  • Shackleton S., Baggenstos D, Menking J.A, Dyonisius M.N, Bereiter B., Bauska T.K, Rhodes R.H, Brook E.J, Petrenko VV, McConnell J.R et al..  2020.  Global ocean heat content in the Last Interglacial. 13
    Abstract Summary:

    The Last Interglacial (129-116 thousand years ago (ka)) represents one of the warmest climate intervals of the past 800,000 years and the most recent time when sea level was metres higher than today. However, the timing and magnitude of the peak warmth varies between reconstructions, and the relative importance of individual sources that contribute to the elevated sea level (mass gain versus seawater expansion) during the Last Interglacial...

  • Simpson C., Herrera-Cubilla A., Jackson J.BC.  2020.  How colonial animals evolve. 6
    Abstract Summary:

    The evolution of modular colonial animals such as reef corals and bryozoans is enigmatic because of the ability for modules to proliferate asexually as whole colonies reproduce sexually. This reproductive duality creates an evolutionary tension between modules and colonies because selection operates at both levels. To understand how this evolutionary conflict is resolved, we compared the evolutionary potential of module- and colony-level...

  • Hull P.M, Bomemann A., Penman D.E, Henehan M.J, Norris RD, Wilson PA, Blum P., Alegret L., Batenburg S.J, Bown P.R et al..  2020.  On impact and volcanism across the Cretaceous-Paleogene boundary. 367:266-+.
    Abstract Summary:

    The cause of the end-Cretaceous mass extinction is vigorously debated, owing to the occurrence of a very large bolide impact and flood basalt volcanism near the boundary. Disentangling their relative importance is complicated by uncertainty regarding kill mechanisms and the relative timing of volcanogenic outgassing, impact, and extinction We used carbon cycle modeling and paleotemperature records to constrain the timing of volcanogenic...

  • Stanley K.M, Say D., Mühle J, Harth CM, Krummel PB, Young D, O'Doherty S.J, Salameh PK, Simmonds PG, Weiss RF et al..  2020.  Increase in global emissions of HFC-23 despite near-total expected reductions. 11
    Abstract Summary:

    Under the Kigali Amendment to the Montreal Protocol, new controls are being implemented to reduce emissions of HFC-23 (CHF3), a by-product during the manufacture of HCFC-22 (CHClF2). Starting in 2015, China and India, who dominate global HCFC-22 production (75% in 2017), set out ambitious programs to reduce HFC-23 emissions. Here, we estimate that these measures should have seen global emissions drop by 87% between 2014 and 2017. Instead,...

  • Dailey S.K, Clift P.D, Kulhanek D.K, Blusztajn J., Routledge C.M, Calves G., O'Sullivan P., Jonell T.N, Pandey D.K, Ando S. et al..  2020.  Large-scale mass wasting on the Miocene continental margin of western India. 132:85-112.
    Abstract Summary:

    A giant mass-transport complex was recently discovered in the eastern Arabian Sea, exceeding in volume all but one other known complex on passive margins worldwide. The complex, named the Nataraja Slide, was drilled by International Ocean Discovery Program (IODP) Expedition 355 in two locations where it is similar to 300 m (Site U1456) and similar to 200 m thick (Site U1457). The top of this mass-transport complex is defined by the presence...

  • Waters C.L, Day JMD, Watanabe S., Sayit K., Zanon V., Olson K.M, Hanan B.B, Widom E..  2020.  Sulfide mantle source heterogeneity recorded in basaltic lavas from the Azores. 268:422-445.
    Abstract Summary:

    New highly siderophile element (HSE: Os, Ir, Ru, Pt, Pd, Re) abundance and Os isotopic compositions, along with major- and trace-element abundance and Sr-Nd-Hf-Pb isotope data are reported for high-MgO (>8-17 wt.%) lavas from the islands of Sao Miguel, Terceira, Pico and Faial in the Azores archipelago. The lavas span the range of Sr-Nd-Hf-Pb isotope and trace-element abundance variability reported previously for the islands. Pico and...

  • Aarons S.M, Arvin L.J, Aciego S.M, Riebe C.S, Johnson K.R, Blakowski M.A, Koornneef J.M, Hart S.C, Barnes M.E, Dove N. et al..  2019.  Competing droughts affect dust delivery to Sierra Nevada. 41
    Abstract Summary:

    The generation and transport of mineral dust is strongly related to climate on seasonal, year-to-year, and glacial-interglacial timescales. The modern dust cycle is influenced by soil moisture, which is partly a function of drought duration and severity. The production and transport of dust can therefore be amplified by global and regional droughts, thereby moderating ecosystem vulnerability to disturbance through the influence of dust on...

  • Seltzer A.M, Ng J., Danskin W.R, Kulongoski JT, Gannon R.S, Stute M., Severinghaus JP.  2019.  Deglacial water-table decline in Southern California recorded by noble gas isotopes. 10
    Abstract Summary:

    Constraining the magnitude of past hydrological change may improve understanding and predictions of future shifts in water availability. Here we demonstrate that water-table depth, a sensitive indicator of hydroclimate, can be quantitatively reconstructed using Kr and Xe isotopes in groundwater. We present the first-ever measurements of these dissolved noble gas isotopes in groundwater at high precision (<= 0.005 parts per thousand amu(-1...

  • Cyronak T., Takeshita Y, Courtney T.A, DeCarlo E.H, Eyre B.D, Kline DI, Martz T., Page H., Price N.N, Smith J. et al..  2019.  Diel temperature and pH variability scale with depth across diverse coral reef habitats.
    Abstract Summary:

    Coral reefs are facing intensifying stressors, largely due to global increases in seawater temperature and decreases in pH. However, there is extensive environmental variability within coral reef ecosystems, which can impact how organisms respond to global trends. We deployed spatial arrays of autonomous sensors across distinct shallow coral reef habitats to determine patterns of spatiotemporal variability in seawater physicochemical...

  • Tian Z., Chen H., Fegley B., Lodders K., Barrat J.A, Day JMD, Wang K..  2019.  Potassium isotopic compositions of howardite-eucrite-diogenite meteorites. 266:611-632.
    Abstract Summary:

    We report new high-precision stable K isotope data for three martian meteorites, one lunar meteorite, one ordinary chondrite, four terrestrial igneous United States Geological Survey (USGS) reference materials, and twenty howardite-eucrite-dio genite [HED] meteorites. The three martian meteorites define a relatively narrow delta K-41 range with an average of -0.36 +/- 0.12 parts per thousand (2 SD) that is slightly heavier than the Bulk...

  • Resplandy L., Keeling RF, Eddebbar Y., Brooks M., Wang R., Bopp L., Long M.C, Dunne J.P, Koeve W., Oschlies A..  2019.  Quantification of ocean heat uptake from changes in atmospheric O-2 and CO2 composition. 9
    Abstract Summary:

    The ocean is the main source of thermal inertia in the climate system. Ocean heat uptake during recent decades has been quantified using ocean temperature measurements. However, these estimates all use the same imperfect ocean dataset and share additional uncertainty due to sparse coverage, especially before 2007. Here, we provide an independent estimate by using measurements of atmospheric oxygen (O-2) and carbon dioxide (CO2) - levels of...

  • Levy Y., Rockwell T.K, Shaw J.H, Plesch A., Driscoll NW, Perea H..  2019.  Structural modeling of the Western Transverse Ranges: An imbricated thrust ramp architecture. 11:868-883.
    Abstract Summary:

    Active fold-and-thrust belts can potentially accommodate large-magnitude earthquakes, so understanding the structure in such regions has both societal and scientific importance. Recent studies have provided evidence for large earthquakes in the Western Transverse Ranges of California, USA. However, the diverse set of conflicting structural models for this region highlights the lack of understanding of the subsurface geometry of faults. A more...

  • Day JMD, Sossi P.A, Shearer C.K, Moynier F..  2019.  Volatile distributions in and on the Moon revealed by Cu and Fe isotopes in the 'Rusty Rock' 66095. 266:131-143.
    Abstract Summary:

    The Apollo 16 'Rusty Rock' impact melt breccia 66095 is a volatile-rich sample, with the volatiles inherited through vapor condensation from an internal lunar source formed during thermo-magmatic evolution of the Moon. We report Cu and Fe isotope data for 66095 and find that bulk-rocks, residues and acid leaches span a relatively limited range of compositions (3.0 +/- 1.3 wt.% FeO [range = 2.0-4.8 wt.%], 5.4 +/- 3.1 ppm Cu [range = 3-12 ppm...

  • Delgado J.A, Sudre J., Tanahara S., Montes I., Hernandez-Ayon J.M, Zirino A..  2019.  Effect of Caribbean Water incursion into the Gulf of Mexico derived from absolute dynamic topography, satellite data, and remotely sensed chlorophyll a. 15:1561-1578.
    Abstract Summary:

    The dynamics of the Loop Current (LC) and the detached Loop Current eddies (LCEs) dominate the surface circulation of the Gulf of Mexico (GoM) and transport Caribbean Water (CW) into the gulf. In this work, 25 years (1993-2017) of daily satellite data are used to investigate the variability of these physical processes and their effect on chlorophyll a (Chl a) concentrations from 1998 to 2017, including temporal changes, mean differences, and...

  • Stephens BM, Wankel SD, J. Beman M, Rabines AJ, Allen AE, Aluwihare LI.  2019.  Euphotic zone nitrification in the California Current Ecosystem.
    Abstract Summary:

    Nitrification, the microbial conversion of ammonium to nitrite then to nitrate, occurs throughout the oceanic water column, yet the environmental factors influencing the production of nitrate in the euphotic zone (EZ) remain unclear. In this study, the natural abundances of N and O isotopes (δ15N and δ18O, respectively) in nitrate were used in an existing model framework to quantify nitrate contributed by EZ nitrification in the California...

  • Stephens B.M, Wankel S.D, Beman J.M, Rabines A.J, Allen A.E, Aluwihare LI.  2019.  Euphotic zone nitrification in the California Current Ecosystem.
    Abstract Summary:

    Nitrification, the microbial conversion of ammonium to nitrite then to nitrate, occurs throughout the oceanic water column, yet the environmental factors influencing the production of nitrate in the euphotic zone (EZ) remain unclear. In this study, the natural abundances of N and O isotopes (delta N-15 and delta O-18, respectively) in nitrate were used in an existing model framework to quantify nitrate contributed by EZ nitrification in the...

  • Asher E., Hornbrook R.S, Stephens B.B, Kinnison D., Morgan E.J, Keeling RF, Atlas E.L, Schauffler S.M, Tilmes S., Kort E.A et al..  2019.  Novel approaches to improve estimates of short-lived halocarbon emissions during summer from the Southern Ocean using airborne observations. 19:14071-14090.
    Abstract Summary:

    Fluxes of halogenated volatile organic compounds (VOCs) over the Southern Ocean remain poorly understood, and few atmospheric measurements exist to constrain modeled emissions of these compounds. We present observations of CHBr3, CH2Br2, CH3I, CHClBr2, CHBrCl2, and CH3Br during the O-2/N-2 Ratio and CO2 Airborne Southern Ocean (ORCAS) study and the second Atmospheric Tomography mission (ATom-2) in January and February of 2016 and 2017. Good...

  • Meskhidze N., Volker C., Al-Abadleh H.A, Barbeau K., Bressac M., Buck C., Bundy R.M, Croot P., Feng Y., Ito A. et al..  2019.  Perspective on identifying and characterizing the processes controlling iron speciation and residence time at the atmosphere-ocean interface. 217
    Abstract Summary:

    It is well recognized that the atmospheric deposition of iron (Fe) affects ocean productivity, atmospheric CO2 uptake, ecosystem diversity, and overall climate. Despite significant advances in measurement techniques and modeling efforts, discrepancies persist between observations and models that hinder accurate predictions of processes and their global effects. Here, we provide an assessment report on where the current state of knowledge is...

  • Coale T.H, Moosburner M., Horak A., Obornik M., Barbeau K.A, Allen A.E.  2019.  Reduction-dependent siderophore assimilation in a model pennate diatom. 116:23609-23617.
    Abstract Summary:

    Iron uptake by diatoms is a biochemical process with global biogeochemical implications. In large regions of the surface ocean diatoms are both responsible for the majority of primary production and frequently experiencing iron limitation of growth. The strategies used by these phytoplankton to extract iron from seawater constrain carbon flux into higher trophic levels and sequestration into sediments. In this study we use reverse genetic...

  • Morgan E.J, Stephens B.B, Long M.C, Keeling RF, Bent J.D, McKain K., Sweeney C, Hoecker-Martinez M.S, Kort E.A.  2019.  Summertime atmospheric boundary layer gradients of O-2 and CO2 over the Southern Ocean.
    Abstract Summary:

    We present airborne observations of the vertical gradient of atmospheric oxygen (delta(O-2/N-2)) and carbon dioxide (CO2) through the atmospheric boundary layer (BL) over the Drake Passage region of the Southern Ocean, during the O-2/N-2 Ratio and CO2 Airborne Southern Ocean Study, from 15 January to 29 February 2016. Gradients were predominately anticorrelated, with excesses of delta(O-2/N-2) and depletions of CO2 found within the boundary...

  • Johnson A.C, Aarons S.M, Dauphas N., Nie N.X, Zeng H., Helz R.T, Romaniello S.J, Anbar A.D.  2019.  Titanium isotopic fractionation in Kilauea Iki lava lake driven by oxide crystallization. 264:180-190.
    Abstract Summary:

    Recent work has demonstrated that titanium (Ti) isotopes undergo mass-dependent isotope fractionation during magmatic differentiation, leaving evolved silicic melts preferentially enriched in heavy Ti isotopes. Preferential incorporation of light Ti isotopes in crystallizing Fe-Ti oxides is thought to be the mechanism responsible for this fractionation in magmatic rocks. To test this hypothesis, we present Ti isotope measurements of Fe-Ti...

  • Courtney T.A, Andersson AJ.  2019.  Evaluating measurements of coral reef net ecosystem calcification rates. 38:997-1006.
    Abstract Summary:

    Monitoring the rates and drivers of coral reef net ecosystem calcification (NEC) under anthropogenic environmental change is critical for predicting associated changes in reef structures and ecosystem services. However, NEC studies to date show weak agreement between studies and notably reveal no relationship between NEC and benthic calcifier cover. In this study, we tested for the sensitivity of calculated NEC to uncertainties in seawater...

  • Wang J.A, Sulla-Menashe D., Woodcock C.E, Sonnentag O., Keeling RF, Friedl M.A.  2019.  Extensive land cover change across Arctic-Boreal Northwestern North America from disturbance and climate forcing.
    Abstract Summary:

    A multitude of disturbance agents, such as wildfires, land use, and climate-driven expansion of woody shrubs, is transforming the distribution of plant functional types across Arctic-Boreal ecosystems, which has significant implications for interactions and feedbacks between terrestrial ecosystems and climate in the northern high-latitude. However, because the spatial resolution of existing land cover datasets is too coarse, large-scale land...

  • Abstract Summary:

    Caribbean coral reefs have transformed into algal-dominated habitats over the past half-century, but the role of specific anthropogenic drivers is unresolved due to the lack of ecosystem-level data predating human disturbance. To better understand the extent and causes of long-term Caribbean reef declines, we produced a continuous 3000-yr record of the ecosystem state of three reefs in Bocas del Toro, Caribbean Panama. From fossils and...

  • Daniel P, J. MJeremiah, Emily K, Mingxun W, E. WMargot, E. AEric, I. ALihini, C. DPieter.  2019.  Non-targeted metabolomics enables the prioritization and tracking of anthropogenic pollutants in coastal seawater.
    Abstract Summary:

    Anthropogenic pollutants inundate marine ecosystems as human population growth and urbanization rapidly increase along the coast. Our analytical methods are typically aimed at measuring and monitoring a restricted number of compounds. To prioritize coastal anthropogenic impacts in a comprehensive fashion, we applied large-scale non-targeted liquid chromatography tandem mass spectrometry. We integrated an advanced data analysis pipeline that...

  • Sastri A.R, Christian J.R, Achterberg E.P, Atamanchuk D., Buck J.JH, Bresnahan P., Duke P.J, Evans W., Gonski S.F, Johnson B. et al..  2019.  Perspectives on in situ sensors for ocean acidification research. 6
    Abstract Summary:

    As ocean acidification (OA) sensor technology develops and improves, in situ deployment of such sensors is becoming more widespread. However, the scientific value of these data depends on the development and application of best practices for calibration, validation, and quality assurance as well as on further development and optimization of the measurement technologies themselves. Here, we summarize the results of a 2-day workshop on OA...

  • Coale TH, Moosburner M, Horák A, Oborník M, Barbeau KA, Allen AE.  2019.  Reduction-dependent siderophore assimilation in a model pennate diatom.
    Abstract Summary:

    Diatoms can access inorganic iron with remarkable efficiency, but this process is contingent on carbonate ion concentration. As ocean acidification reduces carbonate concentration, inorganic iron uptake may be discouraged in favor of carbonate-independent uptake. We report details of an iron assimilation process that needs no carbonate but requires exogenous compounds produced by cooccurring organisms. We show this process to be critical for...

  • Winski D.A, Fudge T.J, Ferris D.G, Osterberg E.C, Fegyveresi J.M, Cole-Dai J., Thundercloud Z., Cox T.S, Kreutz K.J, Ortman N. et al..  2019.  The SP19 chronology for the South Pole Ice Core - Part 1: volcanic matching and annual layer counting. 15:1793-1808.
    Abstract Summary:

    The South Pole Ice Core (SPICEcore) was drilled in 2014-2016 to provide a detailed multi-proxy archive of paleoclimate conditions in East Antarctica during the Holocene and late Pleistocene. Interpretation of these records requires an accurate depth-age relationship. Here, we present the SPICEcore (SP19) timescale for the age of the ice of SPICEcore. SP19 is synchronized to the WD2014 chronology from theWest Antarctic Ice Sheet Divide (WAIS...

  • Yan Y.Z, Bender M.L, Brook E.J, Clifford H.M, Kemeny P.C, Kurbatov A.V, Mackay S., Mayewski P.A, Ng J., Severinghaus JP et al..  2019.  Two-million-year-old snapshots of atmospheric gases from Antarctic ice. 574:663-+.
    Abstract Summary:

    Over the past eight hundred thousand years, glacial-interglacial cycles oscillated with a period of one hundred thousand years ('100k world'1). Ice core and ocean sediment data have shown that atmospheric carbon dioxide, Antarctic temperature, deep ocean temperature, and global ice volume correlated strongly with each other in the 100k world(2-6). Between about 2.8 and 1.2 million years ago, glacial cycles were smaller in magnitude and...

  • Guedes J.D, Hanson S., Higham C., Higham T., Lertcharnrit T..  2019.  The wet and the dry, the wild and the cultivated: subsistence and risk management in ancient Central Thailand.
    Abstract Summary:

    Increasing the productivity and yield of rice in Central Thailand has been a key focus of international and local government policy. Efforts have centered around producing a second winter season of irrigated rice. However, a series of droughts in the region have led to widespread crop failure. We carry out a re-evaluation of weather station and environmental data and combine this with new information from a key archeological site in Central...

  • Gracia E., Grevemeyer I., Bartolome R., Perea H., Martinez-Loriente S., de la Pena L.G, Villasenor A., Klinger Y., C. Iacono L, Diez S. et al..  2019.  Earthquake crisis unveils the growth of an incipient continental fault system. 10
    Abstract Summary:

    Large continental faults extend for thousands of kilometres to form boundaries between rigid tectonic blocks. These faults are associated with prominent topographic features and can produce large earthquakes. Here we show the first evidence of a major tectonic structure in its initial-stage, the Al-Idrissi Fault System (AIFS), in the Alboran Sea. Combining bathymetric and seismic reflection data, together with seismological analyses of the...

  • Highlighted Publication Map of Juan Fernandez Ridge
    Abstract Summary:

    Mantle plume models have been widely applied to explain the formation of ocean island basalts (OIB), with high-3He/4He in their lavas being explained by sampling of a primitive deep mantle source. The Juan Fernandez Islands have 3He/4He (7.8–18 RA) similar to or higher than in mid-ocean ridge basalts (MORB; 8 ± 1 RA) and have been used to both support and refute the mantle plume hypothesis. Ambiguity regarding the origin of the Juan Fernandez...

  • Sanchez S.C, Amaya D.J, Miller AJ, Xie SP, Charles CD.  2019.  The Pacific Meridional Mode over the last millennium. 53:3547-3560.
    Abstract Summary:

    The Pacific Meridional Mode, a coupled ocean-atmospheric interaction responsible for propagating subtropical anomalies to the tropics via thermodynamic mechanisms, features prominently in discussions of the response of climate variability to climate change. However, it is presently unclear how and why the variance in PMM might change, or even if greenhouse gas forcing might lead to heightened activity. Here, PMM variance over the last...

  • Behar N., Shaar R, Tauxe L, Asefaw H., Ebert Y., Heimann A., Koppers A.AP, Ron H.G.  2019.  Paleomagnetism and paleosecular variations from the Plio-Pleistocene Golan Heights volcanic plateau, Israel. 20:4319-4335.
    Abstract Summary:

    Statistical analysis of geomagnetic paleosecular variation (PSV) and time-averaged field has been largely based on global compilations of paleomagnetic data from lava flows. These show different trends in the averaged inclination anomaly (Delta I) between the two hemispheres, with small positive (<2 degrees) anomalies in midsouthern latitudes and large negative (> -5 degrees) anomalies in midnorthern latitudes. To inspect the large...

  • Chen H., Meshik A.P, Pravdivtseva O.V, Day JMD, Wang K..  2019.  Potassium isotope fractionation during high-temperature evaporation determined from the Trinity nuclear test. 522:84-92.
    Abstract Summary:

    Trinitite materials are the post-detonation glassy residues formed from melting and evaporation of arkosic sands during the first nuclear detonation at the Trinity test site, New Mexico on 16th July, 1945. These trinitites provide useful materials for studying elemental and isotopic behaviors associated with high temperature melting and evaporation that is otherwise difficult to achieve under laboratory conditions. Using a high-precision...

  • Abstract Summary:

    The origin of variations in Os-186/Os-188 ratios amongst mantle-derived basaltic and komatiitic lavas remains controversial, with opposing models arguing for deep core-mantle versus shallow mantle sources. Crustal contamination has generally not been favored due to the low Os contents of such sources, meaning that variations in Os-186/Os-188 would require involvement of extremely high proportions of crustal material. Here we re-examine...

  • Say D., Ganesan A.L, Lunt M.F, Rigby M, O'Doherty S, Harth C, Manning A.J, Krummel PB, Bauguitte S..  2019.  Emissions of halocarbons from India inferred through atmospheric measurements. 19:9865-9885.
    Abstract Summary:

    As the second most populous country and third fastest growing economy, India has emerged as a global economic power. As such, its emissions of greenhouse and ozone-depleting gases are of global significance. However, unlike neighbouring China, the Indian sub-continent is very poorly monitored by atmospheric measurement networks. India's halocarbon emissions, here defined as chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs),...

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