Now showing items 1-20 of 248

    • An olivine cumulate outcrop on the floor of Jezero crater, Mars 

      Liu, Y.; Tice, M. M.; Schmidt, M. E.; Treiman, A. H.; Kizovski, T. V.; (2022)
      The geological units on the floor of Jezero crater, Mars, are part of a wider regional stratigraphy of olivine-rich rocks, which extends well beyond the crater. We investigated the petrology of olivine and carbonate-bearing rocks of the Séítah formation in the floor of Jezero. Using multispectral images and x-ray fluorescence data, acquired by the ...
    • Rates of Future Climate Change in the Gulf of Mexico and the Caribbean Sea: Implications for Coral Reef Ecosystems 

      Lawman, A.E.; Dee, S.G.; DeLong, K.L.; Correa, A.M.S. (2022)
      Rising temperatures and ocean acidification due to anthropogenic climate change pose ominous threats to coral reef ecosystems in the Gulf of Mexico (GoM) and the western Caribbean Sea. Unfortunately, the once structurally complex coral reefs in the GoM and Caribbean have dramatically declined since the 1970s; relatively few coral reefs still exhibit ...
    • Autocorrelation Reflectivity of Mars 

      Deng, Sizhuang; Levander, Alan (2020)
      The seismic structure of the Martian interior can shed light on the formation and dynamic evolution of the planet and our solar system. The deployment of the seismograph carried by the InSight mission provides a means to study Martian internal structure. We used ambient noise autocorrelation to analyze the available vertical component seismic data ...
    • A 5-km-thick reservoir with > 380,000 km3 of magma within the ancient Earth's crust 

      Latypov, Rais; Chistyakova, Sofya; Hornsey, Richard A.; Costin, Gelu; van der Merwe, Mauritz (2022)
      Several recent studies have argued that large, long-lived and molten magma chambers may not occur in the shallow Earth’s crust. Here we present, however, field-based observations from the Bushveld Complex that provide evidence to the contrary. In the eastern part of the complex, the magmatic layering continuously drapes across a ~ 4-km-high sloping ...
    • Examining the impact of emissions scenario on lower Mississippi River flood hazard projections 

      Dunne, K. B. J.; Dee, S. G.; Reinders, J.; Muñoz, S. E.; Nittrouer, J. A. (2022)
      The Mississippi River is the largest commercial waterway in North America and one of the most heavily engineered rivers in the world. Future alteration of the river’s hydrology by climate change may increase the vulnerability of flood mitigation and navigation infrastructure implemented to constrain 20th century discharge conditions. Here, we evaluate ...
    • Autocorrelation R2 on Mars 

      Deng, Sizhuang; Levander, Alan (2022)
      A purpose of the Interior Exploration Using Seismic Investigations, Geodesy and Heat Transport (InSight) mission is to reveal the Martian interior structure with seismic data. In this work, ambient noise autocorrelation of the continuously recorded vertical-component seismic signals has extracted the Rayleigh waves that propagate around Mars for one ...
    • Rapid retreat of Thwaites Glacier in the pre-satellite era 

      Graham, Alastair G. C.; Wåhlin, Anna; Hogan, Kelly A.; Nitsche, Frank O.; Heywood, Karen J.; (2022)
      Understanding the recent history of Thwaites Glacier, and the processes controlling its ongoing retreat, is key to projecting Antarctic contributions to future sea-level rise. Of particular concern is how the glacier grounding zone might evolve over coming decades where it is stabilized by sea-floor bathymetric highs. Here we use geophysical data ...
    • Recent Ostracod Fauna of the Western Ross Sea (Antarctica): A Poorly Known Ingredient of Polar Carbonate Factories 

      Salvi, Gianguido; Anderson, John B.; Bertoli, Marco; Castagno, Pasquale; Falco, Pierpaolo; (2022)
      Ostracoda are a minor but recurrent component of Southern Ocean marine carbonate factories, and their low-Mg calcitic skeletal mineralogy helps in ensuring a noteworthy post-mortem resilience. Our study, based upon surface sediment occurrences, contributes to the better definition of their distribution vs. potential controlling factors in Antarctic ...
    • Artificial Soils Reveal Individual Factor Controls on Microbial Processes 

      Del Valle, Ilenne; Gao, Xiaodong; Ghezzehei, Teamrat A.; Silberg, Jonathan J.; Masiello, Caroline A. (2022)
      Soil matrix properties influence microbial behaviors that underlie nutrient cycling, greenhouse gas production, and soil formation. However, the dynamic and heterogeneous nature of soils makes it challenging to untangle the effects of different matrix properties on microbial behaviors. To address this challenge, we developed a tunable artificial soil ...
    • A Framework for the Systematic Selection of Biosensor Chassis for Environmental Synthetic Biology 

      Sridhar, Swetha; Ajo-Franklin, Caroline M.; Masiello, Caroline A. (2022)
      Microbial biosensors sense and report exposures to stimuli, thereby facilitating our understanding of environmental processes. Successful design and deployment of biosensors hinge on the persistence of the microbial host of the genetic circuit, termed the chassis. However, model chassis organisms may persist poorly in environmental conditions. In ...
    • Sedimentological and Geochemical Perspectives on a Marginal Lake Environment Recorded in the Hartmann's Valley and Karasburg Members of the Murray Formation, Gale Crater, Mars 

      Gwizd, S.; Fedo, C.; Grotzinger, J.; Banham, S.; Rivera-Hernández, F.; (2022)
      This study utilizes instruments from the Curiosity rover payload to develop an integrated paleoenvironmental and compositional reconstruction for the 65-m thick interval of stratigraphy comprising the Hartmann's Valley and Karasburg members of the Murray formation, Gale crater, Mars. The stratigraphy consists of cross-stratified sandstone (Facies 1), ...
    • Increasing Health Risks During Outdoor Sports Due To Climate Change in Texas: Projections Versus Attitudes 

      Dee, Sylvia G.; Nabizadeh, Ebrahim; Nittrouer, Christine L.; Baldwin, Jane W.; Li, Chelsea; (2022)
      Extreme heat is a recognized threat to human health. This study examines projected future trends of multiple measures of extreme heat across Texas throughout the next century, and evaluates the expected climate changes alongside Texas athletic staff (coach and athletic trainer) attitudes toward heat and climate change. Numerical climate simulations ...
    • Clumped-Isotope Constraint on Upper-Tropospheric Cooling During the Last Glacial Maximum 

      Banerjee, Asmita; Yeung, Laurence Y.; Murray, Lee T.; Tie, Xin; Tierney, Jessica E.; (2022)
      Ice cores and other paleotemperature proxies, together with general circulation models, have provided information on past surface temperatures and the atmosphere's composition in different climates. Little is known, however, about past temperatures at high altitudes, which play a crucial role in Earth's radiative energy budget. Paleoclimate records ...
    • Seismic evidence for lithospheric boudinage and its implications for continental rifting 

      Nguyen, Luan C.; Levander, Alan; Niu, Fenglin; Morgan, Julia; Li, Guoliang (2022)
      The continental rifting that precedes the breakup of a continent and the formation of a new ocean basin is one of the key processes of plate tectonics. Although often viewed as a two-dimensional process, rifted margins exhibit significant variations along strike. We document along-strike variations developed during the ca. 200–160 Ma continental ...
    • Early to middle Miocene ice sheet dynamics in the westernmost Ross Sea (Antarctica): Regional correlations 

      Pérez, Lara F.; McKay, Robert M.; De Santis, Laura; Larter, Robert D.; Levy, Richard H.; (2022)
      The present-day morpho-stratigraphy of the Ross Sea is the result of Cenozoic tectonic and cryospheric events, and constitutes a key record of Antarctica's cryospheric evolution. An enduring problem in interpreting this record in a broader regional context is that the correlation between eastern and western Ross Sea stratigraphy has remained uncertain ...
    • Outgassing through magmatic fractures enables effusive eruption of silicic magma 

      Crozier, Josh; Tramontano, Samantha; Forte, Pablo; Oliva, Sarah Jaye C.; Gonnermann, Helge M.; (2022)
      Several mechanisms have been proposed to allow highly viscous silicic magma to outgas efficiently enough to erupt effusively. There is increasing evidence that challenges the classic foam-collapse model in which gas escapes through permeable bubble networks, and instead suggests that magmatic fracturing and/or accompanying localized fragmentation and ...
    • Burial and Exhumation of Sedimentary Rocks Revealed by the Base Stimson Erosional Unconformity, Gale Crater, Mars 

      Watkins, Jessica A.; Grotzinger, John P.; Stein, Nathan T.; Banham, Steven G.; Gupta, Sanjeev; (2022)
      Sedimentary rocks record the ancient climate of Mars through changes between subaqueous and eolian depositional environments, recognized by their stratal geometries and suites of sedimentary structures. Orbiter- and rover-image-based geologic mapping show a dynamic evolution of the 5-km-thick sedimentary sequence exposed along the flanks of Aeolis ...
    • Tridymite in a lacustrine mudstone in Gale Crater, Mars: Evidence for an explosive silicic eruption during the Hesperian 

      Payré, V.; Siebach, K. L.; Thorpe, M. T.; Antoshechkina, P.; Rampe, E. B. (2022)
      The unexpected detection of ∼16 wt.% monoclinic tridymite, a high-temperature silica polymorph, within an otherwise lacustrine mudstone in Gale crater, Mars raises significant questions about its formation and the extent of magmatic evolution on that planet. The rock sample, analyzed by the X-ray diffractometer onboard the Curiosity rover, also ...
    • Watching the Cryosphere Thaw: Seismic Monitoring of Permafrost Degradation Using Distributed Acoustic Sensing During a Controlled Heating Experiment 

      Cheng, Feng; Lindsey, Nathaniel J.; Sobolevskaia, Valeriia; Dou, Shan; Freifeld, Barry; (2022)
      Permafrost degradation is rapidly increasing in response to a warming Arctic climate, altering landscapes and damaging critical infrastructure. Solutions for monitoring permafrost thaw dynamics are essential to understand biogeochemical feedbacks as well as to issue warnings for hazardous geotechnical conditions. We investigate the feasibility of ...
    • Geologic Evidence of Lithostatic Pore Fluid Pressures the Base of the Subduction Seismogenic Zone 

      Condit, C. B.; French, M. E. (2022)
      Geophysical and rheological work below the subduction seismogenic zone suggest that elevated pore fluid pressures (Pfs) may facilitate slow slip and tremor. However, quantification of Pf and its variation in this environment remain indirect and incomplete. We examine brittle-frictional deformation within metasedimentary rocks from an exhumed subduction ...