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Full-Text Articles in Physical Sciences and Mathematics
Modulation Of Late Pleistocene Enso Strength By The Tropical Pacific Thermocline, Gerald T. Rustic, Pratigya J. Polissar, Ana Christina Ravelo, Sarah M. White
Modulation Of Late Pleistocene Enso Strength By The Tropical Pacific Thermocline, Gerald T. Rustic, Pratigya J. Polissar, Ana Christina Ravelo, Sarah M. White
School of Earth & Environment Faculty Scholarship
The El Niño Southern Oscillation (ENSO) is highly dependent on coupled atmosphere-ocean interactions and feedbacks, suggesting a tight relationship between ENSO strength and background climate conditions. However, the extent to which background climate state determines ENSO behavior remains in question. Here we present reconstructions of total variability and El Niño amplitude from individual foraminifera distributions at discrete time intervals over the past ~285,000 years across varying atmospheric CO2 levels, global ice volume and sea level, and orbital insolation forcing. Our results show a strong correlation between eastern tropical Pacific Ocean mixed-layer thickness and both El Niño amplitude and central Pacific …
Meteoritic Evidence For A Ceres-Sized Water-Rich Carbonaceous Chondrite Parent Asteroid, V E. Hamilton, C A. Goodrich, A H. Treiman, Harold Connolly Jr., M E. Zolensky, M H. Shaddad
Meteoritic Evidence For A Ceres-Sized Water-Rich Carbonaceous Chondrite Parent Asteroid, V E. Hamilton, C A. Goodrich, A H. Treiman, Harold Connolly Jr., M E. Zolensky, M H. Shaddad
School of Earth & Environment Faculty Scholarship
Carbonaceous chondrite meteorites record the earliest stages of Solar System geo-logical activities and provide insight into their parent bodies' histories. Some carbonaceous chondrites are volumetrically dominated by hydrated minerals, providing evidence for low temperature and pressure aqueous alteration1. Others are dominated by anhydrous minerals and textures that indicate high temperature metamorphism in the absence of aqueous fluids1. Evidence of hydrous metamorphism at intermediate pressures and temperatures in carbonaceous chondrite parent bodies has been virtually absent. Here we show that an ungrouped, aqueously altered carbonaceous chondrite fragment (numbered 202) from the Almahata Sitta (AhS) meteorite contains an assemblage of minerals, including …
Report On Icdp Deep Dust Workshops: Probing Continental Climate Of The Late Paleozoic Icehouse-Greenhouse Transition And Beyond, Gerilyn S. Soreghan, Laurent Beccaletto, Kathleen C. Benison, Sylvie Borquin, Georg Feulner, Natsuko Hamamura, Michael Hamilton, Nicholas G. Heavens, Linda Hinnov, Adam Huttenlocker, Cindy Looy, Lily Pfeifer, Stephane Pochat, Mehrdad Sarder Abadi, James Zambito
Report On Icdp Deep Dust Workshops: Probing Continental Climate Of The Late Paleozoic Icehouse-Greenhouse Transition And Beyond, Gerilyn S. Soreghan, Laurent Beccaletto, Kathleen C. Benison, Sylvie Borquin, Georg Feulner, Natsuko Hamamura, Michael Hamilton, Nicholas G. Heavens, Linda Hinnov, Adam Huttenlocker, Cindy Looy, Lily Pfeifer, Stephane Pochat, Mehrdad Sarder Abadi, James Zambito
School of Earth & Environment Faculty Scholarship
Chamberlin and Salisbury's assessment of the Permian a century ago captured the essence of the period: it is an interval of extremes yet one sufficiently recent to have affected a biosphere with near-modern complexity. The events of the Permian – the orogenic episodes, massive biospheric turnovers, both icehouse and greenhouse antitheses, and Mars-analog lithofacies – boggle the imagination and present us with great opportunities to explore Earth system behavior. The ICDP-funded workshops dubbed “Deep Dust,” held in Oklahoma (USA) in March 2019 (67 participants from nine countries) and Paris (France) in January 2020 (33 participants from eight countries), focused on …
Molecular Tests Support The Viability Of Rare Earth Elements As Proxies For Fossil Biomolecule Preservation, Paul V. Ullmann, Kristyn K. Voegele, David E. Grandstaff, Richard D. Ash, Wenxia Zheng, Elena R. Schroeter, Mary H. Schweitzer, Kenneth J. Lacovara
Molecular Tests Support The Viability Of Rare Earth Elements As Proxies For Fossil Biomolecule Preservation, Paul V. Ullmann, Kristyn K. Voegele, David E. Grandstaff, Richard D. Ash, Wenxia Zheng, Elena R. Schroeter, Mary H. Schweitzer, Kenneth J. Lacovara
School of Earth & Environment Faculty Scholarship
The rare earth element (REE) composition of a fossil bone reflects its chemical alteration during diagenesis. Consequently, fossils presenting low REE concentrations and/or REE profiles indicative of simple diffusion, signifying minimal alteration, have been proposed as ideal candidates for paleomolecular investigation. We directly tested this prediction by conducting multiple biomolecular assays on a well-preserved fibula of the dinosaur Edmontosaurus from the Cretaceous Hell Creek Formation previously found to exhibit low REE concentrations and steeply-declining REE profiles. Gel electrophoresis identified the presence of organic material in this specimen, and subsequent immunofluorescence and enzyme-linked immunosorbant assays identified preservation of epitopes of the …
Global Patterns Of Recent Mass Movement On Asteroid (101955) Bennu, E. R. Jawin, K. J. Walsh, O. S. Barnouin, T. J. Mccoy, R.-L. Ballouz, D. N. Dellagiustina, Harold Connolly Jr.
Global Patterns Of Recent Mass Movement On Asteroid (101955) Bennu, E. R. Jawin, K. J. Walsh, O. S. Barnouin, T. J. Mccoy, R.-L. Ballouz, D. N. Dellagiustina, Harold Connolly Jr.
School of Earth & Environment Faculty Scholarship
The exploration of near‐Earth asteroids has revealed dynamic surfaces characterized by mobile, unconsolidated material that responds to local geophysical gradients, resulting in distinct morphologies and boulder distributions. The OSIRIS‐REx (Origins, Spectral Interpretation, Resource Identification, and Security‐Regolith Explorer) mission confirmed that asteroid (101955) Bennu is a rubble pile with an unconsolidated surface dominated by boulders. In this work, we documented morphologies indicative of mass movement on Bennu and assessed the relationship to slope and other geologic features on the surface. We found globally distributed morphologic evidence of mass movement on Bennu up to ~70° latitude and on spatial scales ranging from …
Meteoroid Impacts As A Source Of Bennu's Particle Ejection Events, W. F. Bottke, A. V. Moorhead, Harold Connolly Jr., C. W. Hergenrother, J. L. Molaro, P. Michel
Meteoroid Impacts As A Source Of Bennu's Particle Ejection Events, W. F. Bottke, A. V. Moorhead, Harold Connolly Jr., C. W. Hergenrother, J. L. Molaro, P. Michel
School of Earth & Environment Faculty Scholarship
Asteroid (101955) Bennu, a near‐Earth object with a primitive carbonaceous chondrite‐like composition, was observed by the Origins, Spectral Interpretation, Resource Identification, and Security‐Regolith Explorer (OSIRIS‐REx) spacecraft to undergo multiple particle ejection events near perihelion between December 2018 and February 2019. The three largest events observed during this period, which all occurred 3.5 to 6 hr after local noon, placed numerous particles <10 cm on temporary orbits around Bennu. Here we examine whether these events could have been produced by sporadic meteoroid impacts using the National Aeronautics and Space Administration's (NASA) Meteoroid Engineering Model 3.0. Most projectiles that impact Bennu come from nearly isotropic or Jupiter‐family comets and have evolved toward the Sun by Poynting‐Robertson drag. We find that 7,000‐J impacts on Bennu occur with a biweekly cadence near perihelion, with a preference to strike in the late afternoon (~6 pm local time). This timing matches observations. Crater scaling laws also indicate that these impact energies can reproduce the sizes and masses of the largest observed particles, provided the surface has the cohesive properties of weak, porous materials. Bennu's ejection events could be caused by the same kinds of meteoroid impacts that created the Moon's asymmetric debris cloud observed by the Lunar Atmosphere and Dust Environment Explorer (LADEE). Our findings also suggest that fewer ejection events should take place as Bennu moves further away from the Sun, a result that can be tested with future observations.
Geological Factors Impacted Cadmium Availability And Use As An Alternative Cofactor For Zinc In The Carbon Fixation Pathways Of Marine Diatoms, Naman Srivastava, Stephanie J. Spielman, Shaunna M. Morrison, Eli K. Moore
Geological Factors Impacted Cadmium Availability And Use As An Alternative Cofactor For Zinc In The Carbon Fixation Pathways Of Marine Diatoms, Naman Srivastava, Stephanie J. Spielman, Shaunna M. Morrison, Eli K. Moore
School of Earth & Environment Faculty Scholarship
Transition metal cofactors are crucial for many biological processes. Despite being primarily considered to be toxic, the transition metal cadmium (Cd) was discovered to be a substitute for zinc (Zn) in photosynthetic carbon fixation pathways in marine diatoms. However, it is not known how conditions in the geosphere impacted Cd availability and its incorporation as an alternative metal cofactor for phytoplankton. We employed mineral chemistry network analysis to investigate which geochemical factors may have influenced the availability of Cd and Zn during the putative time period that alternative Cd-based pathway evolved. Our results show that Zn minerals are more chemically …
Loess In Eastern Equatorial Pangea Archives A Dusty Atmosphere And Possible Upland Glaciation, Lily Pfeifer, Gerilyn S. Soreghan, Stephane Pochat, Jean Van Den Driessche
Loess In Eastern Equatorial Pangea Archives A Dusty Atmosphere And Possible Upland Glaciation, Lily Pfeifer, Gerilyn S. Soreghan, Stephane Pochat, Jean Van Den Driessche
School of Earth & Environment Faculty Scholarship
Carboniferous–Permian strata in basins within the Central Pangean Mountains in France archive regional paleoequatorial climate during a unique interval in geological history (Pangea assembly, ice-age collapse, megamonsoon inception). The voluminous (∼1.5 km) succession of exclusively fine-grained red beds that comprises the Permian Salagou Formation (Lodève Basin, France) has long been interpreted to record either lacustrine or fluvial deposition, primarily based on a local emphasis of subaqueous features in the upper ∼25% of the section. In contrast, data presented here indicate that the lower-middle Salagou Formation is dominated by up to 15-m-thick beds of internally massive red mudstone with abundant pedogenic …
Author Correction: Estimating Global Mean Sea-Level Rise And Its Uncertainties By 2100 And 2300 From An Expert Survey, Benjamin P. Horton, Nicole S. Khan, Niamh Cahill, Janice S.H. Lee, Timothy A. Shaw, Andra J. Garner, Andrew C. Kemp, Simon E. Engelhart, Stefan Rahmstorf
Author Correction: Estimating Global Mean Sea-Level Rise And Its Uncertainties By 2100 And 2300 From An Expert Survey, Benjamin P. Horton, Nicole S. Khan, Niamh Cahill, Janice S.H. Lee, Timothy A. Shaw, Andra J. Garner, Andrew C. Kemp, Simon E. Engelhart, Stefan Rahmstorf
School of Earth & Environment Faculty Scholarship
Correction to: NPJ Climate and Atmospheric Science https://doi.org/10.1038/s41612-020-0121-5, published online 08 May 2020
Collisional Formation Of Top-Shaped Asteroids And Implications For The Origins Of Ryugu And Bennu, P. Michel, R.-L. Ballouz, O. S. Barnouin, M. Jutzi, K. J. Walsh, B. H. May, C. Manzoni, D. C. Richardson, S. R. Schwartz, S. Sugita, S. Watanabe, H. Miyamoto, M. Hirabayashi, W. F. Bottke, Harold Connolly Jr., M. Yoshikawa, D. S. Lauretta
Collisional Formation Of Top-Shaped Asteroids And Implications For The Origins Of Ryugu And Bennu, P. Michel, R.-L. Ballouz, O. S. Barnouin, M. Jutzi, K. J. Walsh, B. H. May, C. Manzoni, D. C. Richardson, S. R. Schwartz, S. Sugita, S. Watanabe, H. Miyamoto, M. Hirabayashi, W. F. Bottke, Harold Connolly Jr., M. Yoshikawa, D. S. Lauretta
School of Earth & Environment Faculty Scholarship
Asteroid shapes and hydration levels can serve as tracers of their history and origin. For instance, the asteroids (162173) Ryugu and (101955) Bennu have an oblate spheroidal shape with a pronounced equator, but contain different surface hydration levels. Here we show, through numerical simulations of large asteroid disruptions, that oblate spheroids, some of which have a pronounced equator defining a spinning top shape, can form directly through gravitational reaccumulation. We further show that rubble piles formed in a single disruption can have similar porosities but variable degrees of hydration. The direct formation of top shapes from single disruption alone can …
Estimating Global Mean Sea-Level Rise And Its Uncertainties By 2100 And 2300 From An Expert Survey, Benjamin P. Horton, Nicole S. Khan, Niamh Cahill, Janice S.H. Lee, Timothy A. Shaw, Andra J. Garner, Andrew C. Kemp, Simon E. Engelhart, Stefan Rahmstorf
Estimating Global Mean Sea-Level Rise And Its Uncertainties By 2100 And 2300 From An Expert Survey, Benjamin P. Horton, Nicole S. Khan, Niamh Cahill, Janice S.H. Lee, Timothy A. Shaw, Andra J. Garner, Andrew C. Kemp, Simon E. Engelhart, Stefan Rahmstorf
School of Earth & Environment Faculty Scholarship
Sea-level rise projections and knowledge of their uncertainties are vital to make informed mitigation and adaptation decisions. To elicit projections from members of the scientific community regarding future global mean sea-level (GMSL) rise, we repeated a survey originally conducted five years ago. Under Representative Concentration Pathway (RCP) 2.6, 106 experts projected a likely (central 66% probability) GMSL rise of 0.30–0.65 m by 2100, and 0.54–2.15 m by 2300, relative to 1986–2005. Under RCP 8.5, the same experts projected a likely GMSL rise of 0.63–1.32 m by 2100, and 1.67–5.61 m by 2300. Expert projections for 2100 are similar to those …
230th Normalization: New Insights On An Essential Tool For Quantifying Sedimentary Fluxes In The Modern And Quaternary Ocean, Kassandra M. Costa, Christopher T. Hayes, Robert F. Anderson, Frank J. Pavia, Alexandra Bausch, Feifei Deng, Jean-Claude Dutay, Walter Geibert, Christoph Heinze, Lauren Kipp, Et Al
230th Normalization: New Insights On An Essential Tool For Quantifying Sedimentary Fluxes In The Modern And Quaternary Ocean, Kassandra M. Costa, Christopher T. Hayes, Robert F. Anderson, Frank J. Pavia, Alexandra Bausch, Feifei Deng, Jean-Claude Dutay, Walter Geibert, Christoph Heinze, Lauren Kipp, Et Al
School of Earth & Environment Faculty Scholarship
230Th normalization is a valuable paleoceanographic tool for reconstructing high-resolution sediment fluxes during the late Pleistocene (last ~500,000 years). As its application has expanded to ever more diverse marine environments, the nuances of 230Th systematics, with regard to particle type, particle size, lateral advective/diffusive redistribution, and other processes, have emerged. We synthesized over 1000 sedimentary records of 230Th from across the global ocean at two time slices, the late Holocene (0–5,000 years ago, or 0–5 ka) and the Last Glacial Maximum (18.5–23.5 ka), and investigated the spatial structure of 230Th-normalized mass fluxes. On a global scale, sedimentary mass fluxes were …