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Abell JT, Winckler G, Anderson RF, Herbert TD. Poleward and weakened westerlies during Pliocene warmth. Nature 2021; 589:70-75. [PMID: 33408375 DOI: 10.1038/s41586-020-03062-1] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 10/19/2020] [Indexed: 11/09/2022]
Abstract
The prevailing mid-latitude westerly winds, known as the westerlies, are a fundamental component of the climate system because they have a crucial role in driving surface ocean circulation1 and modulating air-sea heat, momentum and carbon exchange1-3. Recent work suggests that westerly wind belts are migrating polewards in response to anthropogenic forcing4,5. Reconstructing the westerlies during past warm periods such as the Pliocene epoch, in which atmospheric carbon dioxide (CO2) was about 350 to 450 parts per million6 and temperatures were about 2 to 4 degrees Celsius higher than today7, can improve our understanding of changes in the position and strength of these wind systems as the climate continues to warm. Here we show that the westerlies were weaker and more poleward during the warm Pliocene than during glacial periods after the intensification of Northern Hemisphere glaciation (iNHG), which occurred around 2.73 million years ago8. Our results, which are based on dust and export productivity reconstructions, indicate that major ice sheet development during the iNHG was accompanied by substantial increases in dust fluxes in the mid-latitude North Pacific Ocean, especially compared to those in the subarctic North Pacific. Following this shift, changes in dust and productivity largely track the glacial-interglacial cycles of the late Pliocene and early Pleistocene epochs. On the basis of this pattern, we infer that shifts in the westerlies were primarily driven by variations in Plio-Pleistocene thermal gradients and ice volume. By combining this relationship with other dust records9-11 and climate modelling results12, we find that the proposed changes in the westerlies were globally synchronous. If the Pliocene is predictive of future warming, we posit that continued poleward movement and weakening of the present-day westerlies in both hemispheres can be expected.
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Affiliation(s)
- Jordan T Abell
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA. .,Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA.
| | - Gisela Winckler
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA.,Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA
| | - Robert F Anderson
- Lamont-Doherty Earth Observatory, Columbia University, Palisades, NY, USA.,Department of Earth and Environmental Sciences, Columbia University, New York, NY, USA
| | - Timothy D Herbert
- Department of Earth, Environmental and Planetary Sciences, Brown University, Providence, RI, USA
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Farley KA, Malespin C, Mahaffy P, Grotzinger JP, Vasconcelos PM, Milliken RE, Malin M, Edgett KS, Pavlov AA, Hurowitz JA, Grant JA, Miller HB, Arvidson R, Beegle L, Calef F, Conrad PG, Dietrich WE, Eigenbrode J, Gellert R, Gupta S, Hamilton V, Hassler DM, Lewis KW, McLennan SM, Ming D, Navarro-González R, Schwenzer SP, Steele A, Stolper EM, Sumner DY, Vaniman D, Vasavada A, Williford K, Wimmer-Schweingruber RF. In situ radiometric and exposure age dating of the martian surface. Science 2013; 343:1247166. [PMID: 24324273 DOI: 10.1126/science.1247166] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
We determined radiogenic and cosmogenic noble gases in a mudstone on the floor of Gale Crater. A K-Ar age of 4.21 ± 0.35 billion years represents a mixture of detrital and authigenic components and confirms the expected antiquity of rocks comprising the crater rim. Cosmic-ray-produced (3)He, (21)Ne, and (36)Ar yield concordant surface exposure ages of 78 ± 30 million years. Surface exposure occurred mainly in the present geomorphic setting rather than during primary erosion and transport. Our observations are consistent with mudstone deposition shortly after the Gale impact or possibly in a later event of rapid erosion and deposition. The mudstone remained buried until recent exposure by wind-driven scarp retreat. Sedimentary rocks exposed by this mechanism may thus offer the best potential for organic biomarker preservation against destruction by cosmic radiation.
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Affiliation(s)
- K A Farley
- Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA 91125, USA
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Helium isotope investigation on magnetic reversal boundaries of loess-paleosol sequence at Luochuan, central Chinese Loess Plateau. CHINESE SCIENCE BULLETIN-CHINESE 2007. [DOI: 10.1007/s11434-007-0319-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Farley KA, Vokrouhlický D, Bottke WF, Nesvorný D. A late Miocene dust shower from the break-up of an asteroid in the main belt. Nature 2006; 439:295-7. [PMID: 16421563 DOI: 10.1038/nature04391] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2005] [Accepted: 10/31/2005] [Indexed: 11/08/2022]
Abstract
Throughout the history of the Solar System, Earth has been bombarded by interplanetary dust particles (IDPs), which are asteroid and comet fragments of diameter approximately 1-1,000 microm. The IDP flux is believed to be in quasi-steady state: particles created by episodic main belt collisions or cometary fragmentation replace those removed by comminution, dynamical ejection, and planetary or solar impact. Because IDPs are rich in 3He, seafloor sediment 3He concentrations provide a unique means of probing the major events that have affected the IDP flux and its source bodies over geological timescales. Here we report that collisional disruption of the >150-km-diameter asteroid that created the Veritas family 8.3 +/- 0.5 Myr ago also produced a transient increase in the flux of interplanetary dust-derived 3He. The increase began at 8.2 +/- 0.1 Myr ago, reached a maximum of approximately 4 times pre-event levels, and dissipated over approximately 1.5 Myr. The terrestrial IDP accretion rate was overwhelmingly dominated by Veritas family fragments during the late Miocene. No other event of this magnitude over the past approximately 10(8) yr has been deduced from main belt asteroid orbits. One remarkably similar event is present in the 3He record 35 Myr ago, but its origin by comet shower or asteroid collision remains uncertain.
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Affiliation(s)
- Kenneth A Farley
- Division of Geological and Planetary Sciences, California Institute of Technology, MS 170-25, Pasadena, California 91125, USA.
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Dowling CB, Poreda RJ, Hunt AG, Carey AE. Ground water discharge and nitrate flux to the Gulf of Mexico. GROUND WATER 2004; 42:401-417. [PMID: 15161157 DOI: 10.1111/j.1745-6584.2004.tb02688.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
Ground water samples (37 to 186 m depth) from Baldwin County, Alabama, are used to define the hydrogeology of Gulf coastal aquifers and calculate the subsurface discharge of nutrients to the Gulf of Mexico. The ground water flow and nitrate flux have been determined by linking ground water concentrations to 3H/3He and 4He age dates. The middle aquifer (A2) is an active flow system characterized by postnuclear tritium levels, moderate vertical velocities, and high nitrate concentrations. Ground water discharge could be an unaccounted source for nutrients in the coastal oceans. The aquifers annually discharge 1.1 +/- 0.01 x 10(8) moles of nitrate to the Gulf of Mexico, or 50% and 0.8% of the annual contributions from the Mobile-Alabama River System and the Mississippi River System, respectively. In southern Baldwin County, south of Loxley, increasing reliance on ground water in the deeper A3 aquifer requires accurate estimates of safe ground water withdrawal. This aquifer, partially confined by Pliocene clay above and Pensacola Clay below, is tritium dead and contains elevated 4He concentrations with no nitrate and estimated ground water ages from 100 to 7000 years. The isotopic composition and concentration of natural gas diffusing from the Pensacola Clay into the A3 aquifer aids in defining the deep ground water discharge. The highest 4He and CH4 concentrations are found only in the deepest sample (Gulf State Park), indicating that ground water flow into the Gulf of Mexico suppresses the natural gas plume. Using the shape of the CH4-He plume and the accumulation of 4He rate (2.2 +/- 0.8 microcc/kg/1000 years), we estimate the natural submarine discharge and the replenishment rate for the A3 aquifer.
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Affiliation(s)
- Carolyn B Dowling
- Department of Earth and Environmental Sciences, University of Rochester, Rochester, NY 14627, USA
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Lanci L. Magnetization of Greenland ice and its relationship with dust content. ACTA ACUST UNITED AC 2004. [DOI: 10.1029/2003jd004433] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Poreda RJ, Becker L. Fullerenes and interplanetary dust at the Permian-Triassic boundary. ASTROBIOLOGY 2003; 3:75-90. [PMID: 12804366 DOI: 10.1089/153110703321632435] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
We recently presented new evidence that an impact occurred approximately 250 million years ago at the Permian-Triassic boundary (PTB), triggering the most severe mass extinction in the history of life on Earth. We used a new extraterrestrial tracer, fullerene, a third carbon carrier of noble gases besides diamond and graphite. By exploiting the unique properties of this molecule to trap noble gases inside of its caged structure (helium, neon, argon), the origin of the fullerenes can be determined. Here, we present new evidence for fullerenes with extraterrestrial noble gases in the PTB at Graphite Peak, Antarctica, similar to PTB fullerenes from Meishan, China and Sasayama, Japan. In addition, we isolated a (3)He-rich magnetic carrier phase in three fractions from the Graphite Peak section. The noble gases in this magnetic fraction were similar to zero-age deep-sea interplanetary dust particles (IDPs) and some magnetic grains isolated from the Cretaceous-Tertiary boundary. The helium and neon isotopic compositions for both the bulk Graphite Peak sediments and an isolated magnetic fraction from the bulk material are consistent with solar-type gases measured in zero-age deep-sea sediments and point to a common source, namely, the flux of IDPs to the Earth's surface. In this instance, the IDP noble gas signature for the bulk sediment can be uniquely decoupled from fullerene, demonstrating that two separate tracers are present (direct flux of IDPs for (3)He vs. giant impact for fullerene).
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Affiliation(s)
- Robert J Poreda
- Department of Earth and Environmental Sciences, University of Rochester, Rochester, New York, USA
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Becker L, Poreda RJ, Hunt AG, Bunch TE, Rampino M. Impact event at the Permian-Triassic boundary: evidence from extraterrestrial noble gases in fullerenes. Science 2001; 291:1530-3. [PMID: 11222855 DOI: 10.1126/science.1057243] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
The Permian-Triassic boundary (PTB) event, which occurred about 251.4 million years ago, is marked by the most severe mass extinction in the geologic record. Recent studies of some PTB sites indicate that the extinctions occurred very abruptly, consistent with a catastrophic, possibly extraterrestrial, cause. Fullerenes (C60 to C200) from sediments at the PTB contain trapped helium and argon with isotope ratios similar to the planetary component of carbonaceous chondrites. These data imply that an impact event (asteroidal or cometary) accompanied the extinction, as was the case for the Cretaceous-Tertiary extinction event about 65 million years ago.
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Affiliation(s)
- L Becker
- Department of Earth and Space Sciences, University of Washington, Box 351310, Seattle, WA 98195-1310 USA.
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Anbar AD, Zahnle KJ, Arnold GL, Mojzsis SJ. Extraterrestrial iridium, sediment accumulation and the habitability of the early Earth's surface. ACTA ACUST UNITED AC 2001. [DOI: 10.1029/2000je001272] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Kastner M. Oceanic minerals: their origin, nature of their environment, and significance. Proc Natl Acad Sci U S A 1999; 96:3380-7. [PMID: 10097047 PMCID: PMC34278 DOI: 10.1073/pnas.96.7.3380] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The chemical and isotopic compositions of oceanic biogenic and authigenic minerals contain invaluable information on the evolution of seawater, hence on the history of interaction between tectonics, climate, ocean circulation, and the evolution of life. Important advances and greater understanding of (a) key minor and trace element cycles with various residence times, (b) isotopic sources and sinks and fractionation behaviors, and (c) potential diagenetic problems, as well as developments in high-precision instrumentation, recently have been achieved. These advances provided new compelling evidence that neither gradualism nor uniformitarianism can explain many of the new important discoveries obtained from the chemistry and isotopic compositions of oceanic minerals. Presently, the best-developed geochemical proxies in biogenic carbonates are 18O/16O and Sr/Ca ratios (possibly Mg/Ca) for temperature; 87Sr/86Sr for input sources, Cd/Ca and Ba/Ca ratios for phosphate and alkalinity concentrations, respectively, thus also for ocean circulation; 13C/12C for ocean productivity; B isotopes for seawater pH;, U, Th isotopes, and 14C for dating; and Sr and Mn concentrations for diagenesis. The oceanic authigenic minerals most widely used for chemical paleoceanography are barite, evaporite sulfates, and hydrogenous ferromanganese nodules. Marine barite is an effective alternative monitor of seawater 87Sr/86Sr, especially where carbonates are diagenetically altered or absent. It also provides a high-resolution record of seawater sulfate S isotopes, (evaporite sulfates only carry an episodic record), with new insights on factors affecting the S and C cycles and atmospheric oxygen. High-resolution studies of Sr, Nd, and Pb isotopes of well-dated ferromanganese nodules contain invaluable records on climate driven changes in oceanic circulation.
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Affiliation(s)
- M Kastner
- Scripps Institution of Oceanography, University of California-San Diego, La Jolla, CA 92093-0212, USA
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Brownlee D. Ancient cosmic spherules. Nature 1998; 395:113, 115. [PMID: 9744264 DOI: 10.1038/25840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Farley KA, Montanari A, Shoemaker EM, Shoemaker CS. Geochemical evidence for a comet shower in the late Eocene. Science 1998; 280:1250-3. [PMID: 9596575 DOI: 10.1126/science.280.5367.1250] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Analyses of pelagic limestones indicate that the flux of extraterrestrial helium-3 to Earth was increased for a 2.5-million year (My) period in the late Eocene. The enhancement began approximately 1 My before and ended approximately 1.5 My after the major impact events that produced the large Popigai and Chesapeake Bay craters approximately 36 million years ago. The correlation between increased concentrations of helium-3, a tracer of fine-grained interplanetary dust, and large impacts indicates that the abundance of Earth-crossing objects and dustiness in the inner solar system were simultaneously but only briefly enhanced. These observations provide evidence for a comet shower triggered by an impulsive perturbation of the Oort cloud.
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Affiliation(s)
- K A Farley
- Division of Geological and Planetary Sciences, California Institute of Technology, MS 170-25, Pasadena, CA 91125, USA.
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Kortenkamp SJ, Dermott SF. A 100,000-year periodicity in the accretion rate of interplanetary dust. Science 1998; 280:874-6. [PMID: 9572725 DOI: 10.1126/science.280.5365.874] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022]
Abstract
Numerical modeling of the orbital evolution of interplanetary dust particles revealed that, over the past 1.2 million years, the rate of accretion of dust by Earth has varied by a factor of 2 to 3. These variations display a 100,000-year periodicity and are anticorrelated with Earth's changing orbital eccentricity. Extraterrestrial helium-3 concentrations in a deep-sea sediment core display a similar periodicity but are 50,000 years out of phase with the predicted variations. Also, because collisions between large bodies in the asteroid belt are inevitable, it is expected that large-amplitude stochastic variations on 10(7)- to 10(8)-year time scales would be superimposed on the 10(5)-year periodic variations.
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Affiliation(s)
- SJ Kortenkamp
- S. J. Kortenkamp, Department of Terrestrial Magnetism, Carnegie Institution of Washington, 5241 Broad Branch Road NW, Washington, DC 20015, USA. E-mail: S. F. Dermott, Department of Astronomy, University of Florida, 211 Space
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Muller RA, MacDonald GJ. Spectrum of 100-kyr glacial cycle: orbital inclination, not eccentricity. Proc Natl Acad Sci U S A 1997; 94:8329-34. [PMID: 11607741 PMCID: PMC33747 DOI: 10.1073/pnas.94.16.8329] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Spectral analysis of climate data shows a strong narrow peak with period approximately 100 kyr, attributed by the Milankovitch theory to changes in the eccentricity of the earth's orbit. The narrowness of the peak does suggest an astronomical origin; however the shape of the peak is incompatible with both linear and nonlinear models that attribute the cycle to eccentricity or (equivalently) to the envelope of the precession. In contrast, the orbital inclination parameter gives a good match to both the spectrum and bispectrum of the climate data. Extraterrestrial accretion from meteoroids or interplanetary dust is proposed as a mechanism that could link inclination to climate, and experimental tests are described that could prove or disprove this hypothesis.
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Affiliation(s)
- R A Muller
- Department of Physics and Lawrence Berkeley Laboratory, University of California, Berkeley CA 94720, USA
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Goldanskii VI. Nontraditional Pathways of Extraterrestrial Formation of Prebiotic Matter. J Phys Chem A 1997. [DOI: 10.1021/jp970042i] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Vitalii I. Goldanskii
- N. N. Semenov Institute of Chemical Physics, Russian Academy of Sciences, Ulitsa Kosygina 4, 117334 Moscow, Russia
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Abstract
Fullerenes (C60 and C70) in the Sudbury impact structure contain trapped helium with a 3He/4He ratio of 5.5 x 10(-4) to 5.9 x 10(-4). The 3He/4He ratio exceeds the accepted solar wind value by 20 to 30 percent and is higher by an order of magnitude than the maximum reported mantle value. Terrestrial nuclear reactions or cosmic-ray bombardment are not sufficient to generate such a high ratio. The 3He/4He ratios in the Sudbury fullerenes are similar to those found in meteorites and in some interplanetary dust particles. The implication is that the helium within the C60 molecules at Sudbury is of extraterrestrial origin.
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Affiliation(s)
- L Becker
- Space Science Division, National Aeronautics and Space Administration Ames Research Center, Moffett Field, CA 94035, USA
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