Browsing by Author "Kim, Doyeon"

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    InSight Constraints on the Global Character of the Martian Crust
    Wieczorek, Mark A.; Broquet, Adrien; McLennan, Scott M.; Rivoldini, Attilio; Golombek, Matthew; Antonangeli, Daniele; Beghein, Caroline; Giardini, Domenico; Gudkova, Tamara; Gyalay, Szilard; Johnson, Catherine L.; Joshi, Rakshit; Kim, Doyeon; King, Scott D.; Knapmeyer-Endrun, Brigitte; Lognonne, Philippe; Michaut, Chloe; Mittelholz, Anna; Nimmo, Francis; Ojha, Lujendra; Panning, Mark P.; Plesa, Ana-Catalina; Siegler, Matthew A.; Smrekar, Suzanne E.; Spohn, Tilman; Banerdt, W. Bruce (American Geophysical Union, 2022-05)
    Analyses of seismic data from the InSight mission have provided the first in situ constraints on the thickness of the crust of Mars. These crustal thickness constraints are currently limited to beneath the lander that is located in the northern lowlands, and we use gravity and topography data to construct global crustal thickness models that satisfy the seismic data. These models consider a range of possible mantle and core density profiles, a range of crustal densities, a low-density surface layer, and the possibility that the crustal density of the northern lowlands is greater than that of the southern highlands. Using the preferred InSight three-layer seismic model of the crust, the average crustal thickness of the planet is found to lie between 30 and 72 km. Depending on the choice of the upper mantle density, the maximum permissible density of the northern lowlands and southern highlands crust is constrained to be between 2,850 and 3,100 kg m(-3). These crustal densities are lower than typical Martian basaltic materials and are consistent with a crust that is on average more felsic than the materials found at the surface. We argue that a substantial portion of the crust of Mars is a primary crust that formed during the initial differentiation of the planet. Various hypotheses for the origin of the observed intracrustal seisimic layers are assessed, with our preferred interpretation including thick volcanic deposits, ejecta from the Utopia basin, porosity closure, and differentiation products of a Borealis impact melt sheet.
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    Seismic detection of a deep mantle discontinuity within Mars by InSight
    Huang, Quancheng; Schmerr, Nicholas C.; King, Scott D.; Kim, Doyeon; Rivoldini, Attilio; Plesa, Ana-Catalina; Samuel, Henri; Maguire, Ross R.; Karakostas, Foivos; Lekić, Vedran; Charalambous, Constantinos; Collinet, Max; Myhill, Robert; Antonangeli, Daniele; Drilleau, Melanie; Bystricky, Misha; Bollinger, Caroline; Michaut, Chloe; Gudkova, Tamara; Irving, Jessica C. E.; Horleston, Anna; Fernando, Benjamin; Leng, Kuangdai; Nissen-Meyer, Tarje; Bejina, Frederic; Bozdag, Ebru; Beghein, Caroline; Waszek, Lauren; Siersch, Nicki C.; Scholz, John-Robert; Davis, Paul M.; Lognonné, Philippe; Pinot, Baptiste; Widmer-Schnidrig, Rudolf; Panning, Mark P.; Smrekar, Suzanne E.; Spohn, Tilman; Pike, William T.; Giardini, Domenico; Banerdt, W. Bruce (Proceedings of the National Academy of Sciences, 2022-10-18)
    Constraining the thermal and compositional state of the mantle is crucial for deciphering the formation and evolution of Mars. Mineral physics predicts that Mars’ deep mantle is demarcated by a seismic discontinuity arising from the pressure-induced phase transformation of the mineral olivine to its higher-pressure polymorphs, making the depth of this boundary sensitive to both mantle temperature and composition. Here, we report on the seismic detection of a midmantle discontinuity using the data collected by NASA’s InSight Mission to Mars that matches the expected depth and sharpness of the postolivine transition. In five teleseismic events, we observed triplicated P and S waves and constrained the depth of this discontinuity to be 1,006 ± 40 km by modeling the triplicated waveforms. From this depth range, we infer a mantle potential temperature of 1,605 ± 100 K, a result consistent with a crust that is 10 to 15 times more enriched in heat-producing elements than the underlying mantle. Our waveform fits to the data indicate a broad gradient across the boundary, implying that the Martian mantle is more enriched in iron compared to Earth. Through modeling of thermochemical evolution of Mars, we observe that only two out of the five proposed composition models are compatible with the observed boundary depth. Our geodynamic simulations suggest that the Martian mantle was relatively cold 4.5 Gyr ago (1,720 to 1,860 K) and are consistent with a present-day surface heat flow of 21 to 24 mW/m2