Geodynamic diagnostics, scientific visualisation and StagLab 3.0

Crameri, Fabio

doi:10.5194/gmd-11-2541-2018

Cited by 158 publications

(126 citation statements)

References 45 publications

(56 reference statements)

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“…Grid compilation and figures were made using Generic Mapping Tools (GMT; Wessel et al, 2013). Perceptually uniform color maps are used in this study to prevent visual distortion of the data (Crameri, 2018a;Crameri, 2018b). The digital global total sediment thickness (GlobSed) and the oceanic lithosphere age grid will be archived by NCEI.…”

Section: Acknowledgmentsmentioning

confidence: 99%

GlobSed: Updated Total Sediment Thickness in the World's Oceans

Straume

Gaina

Medvedev

et al. 2019

Geochem Geophys Geosyst

278

202

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We present GlobSed, a new global 5‐arc‐minute total sediment thickness grid for the world's oceans and marginal seas. GlobSed covers a larger area than previously published global grids and incorporates updates for the NE Atlantic, Arctic, Southern Ocean, and Mediterranean regions, which results in a 29.7% increase in estimated total oceanic sediment volume. We use this new global grid and a revised global oceanic lithospheric age grid to assess the relationship between the total sediment thickness and age of the underlying oceanic lithosphere and its latitude. An analytical approximation model is used to mathematically describe sedimentation trends in major oceanic basins and to allow paleobathymetric reconstructions at any given geological time. This study provides a much‐needed update of the sediment thickness distribution of the world oceans and delivers a model for sedimentation rates on oceanic crust through time that agrees well with selected drill data used for comparison.

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Section: Acknowledgmentsmentioning

confidence: 99%

GlobSed: Updated Total Sediment Thickness in the World's Oceans

Straume

Gaina

Medvedev

et al. 2019

Geochem Geophys Geosyst

278

202

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“…We thank P. Tackley for the use of his mantle dynamics code StagYY and for his advice. The geodynamic diagnostics and scientific visualisation software StagLab (Crameri, 2017(Crameri, , 2018 is used in this study. M.T.…”

Section: Acknowledgmentsmentioning

confidence: 99%

The environmental effects of very large bolide impacts on early Mars explored with a hierarchy of numerical models

Turbet

Gillmann

Forget

et al. 2020

Icarus

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The origin of the presence of geological and mineralogical evidence that liquid water flowed on the surface of early Mars is now a 50-year-old mystery. It has been proposed (Segura et al., 2002(Segura et al., , 2008(Segura et al., , 2012 that bolide impacts could have triggered a long-term climate change, producing precipitation and runoff that may have altered the surface of Mars in a way that could explain (at least part of) this evidence. Here we use a hierarchy of numerical models (a 3-D Global Climate Model, a 1-D radiative-convective model and a 2-D Mantle Dynamics model) to test that hypothesis and more generally explore the environmental effects of very large bolide impacts (D impactor > 100 km, or D crater > 600 km) on the atmosphere, surface and interior of early Mars.Using a combination of 1-D and 3-D climate simulations, we show that the environmental effects of the largest impact events recorded on Mars are characterized by: (i) a short impact-induced warm period (several tens of Earth years for the surface and atmosphere to be back to ambient conditions after very large impact events); (ii) a low amount of hydrological cycling of water (because there is no surface re-evaporation of precipitation). The total cumulated amount of precipitation (rainfall) can be reasonably well approximated by the initial post-impact atmospheric reservoir of water vapour (coming from the impactor, the impacted terrain and from the sublimation of permanent ice reservoirs heated by the hot ejecta layer); (iii) deluge-style precipitation (∼2.6 m Global Equivalent Layer of surface precipitation per Earth year for our reference simulation, quantitatively in agreement with previous 1-D cloud free climate calculations of Segura et al. 2002), and (iv) precipitation patterns that are uncorrelated with the observed regions of valley networks.However, we show that the impact-induced stable runaway greenhouse state predicted by Segura et al. (2012) is physically inconsistent. We nevertheless confirm the results of Segura et al. (2008) and Urata and Toon (2013) that water ice clouds could in theory significantly extend the duration of the post-impact warm period, and even for cloud coverage significantly lower than predicted in Ramirez and Kasting (2017). However, the range of cloud microphysical properties for which this scenario works is very narrow.Using 2-D Mantle Dynamics simulations we find that large bolide impacts can produce a strong thermal anomaly in the mantle of Mars that can survive and propagate for tens of millions of years. This thermal anomaly could raise the near-surface internal heat flux up to several hundreds of mW/m 2 (i.e. up to ∼ 10 times the ambient flux) for several millions years at the edges of the impact crater. However, such internal heat flux is largely insufficient to keep the martian surface above the melting point of water.In addition to the poor temporal correlation between the formation of the largest basins and valley networks (Fassett and Head, 2011), these arguments indicate that the largest ...

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“…A sample distribution of Lagrangian tracers is also shown using black dots. Note that color maps used in this manuscript are perceptually uniform for unbiased presentation of model data (Crameri, 2018a(Crameri, , 2018b.…”

Section: Energy and Compositionmentioning

confidence: 99%

Improving Mass Conservation With the Tracer Ratio Method: Application to Thermochemical Mantle Flows

Trim

Lowman

Butler

2020

Geochem Geophys Geosyst

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Modeling the evolution of composition in a convecting mantle is difficult since the associated chemical diffusivity is very small. Consequently, compositional evolution is often modeled using the advection equation which is prone to overdiffusion and spurious oscillations unless special numerical schemes are employed. Similar errors can also occur while modeling the evolution of temperature, since mantle convection is advection dominated. One numerical scheme designed to minimize such errors is the tracer ratio method, in which Lagrangian tracers are used to track each composition in the system in addition to carrying local temperature values that are time dependent. However, tracer spacing may become very uneven during evolution, which can contribute to errors in mass and energy conservation. In this study, a tracer repositioning algorithm designed to promote even tracer coverage is presented and tested using over 400 calculations in a large thermal Rayleigh number/buoyancy ratio parameter space. In particular, the effect of tracer repositioning on mass and energy conservation errors is examined. In most cases, we find that energy errors are roughly an order of magnitude less than mass errors, regardless of tracer repositioning. However, in situations with substantial entrainment of compositionally distinct material, mass errors can be reduced by up to an order of magnitude if tracers are repositioned during model evolution. We also find that for a fixed buoyancy ratio, entrainment of basal material decreases as the thermal Rayleigh number increases.

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Geodynamic diagnostics, scientific visualisation and StagLab 3.0

Cited by 158 publications

References 45 publications

GlobSed: Updated Total Sediment Thickness in the World's Oceans

GlobSed: Updated Total Sediment Thickness in the World's Oceans

The environmental effects of very large bolide impacts on early Mars explored with a hierarchy of numerical models

Improving Mass Conservation With the Tracer Ratio Method: Application to Thermochemical Mantle Flows

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