In order to understand the difference between high temperature drop across the mantle's basal thermal boundary layer and much lower plume excess temperatures we evaluated computations with ASPECT. Some of them are published in the Ph.D. thesis of Poulami Roy, some others in previous work. Hence here we only include those models that are not published elsewhere. We also provide the routine to extract maximum and average plume temperatures versus depth. Our results show reduced excess temperatures, if plumes are more sheet-like, similar to 2-D models, or temperature at their source depth is less than at the CMB, for example if they are sourced on top of thermochemical piles. Excess temperatures are further reduced when averaged over the plume conduit or melting region.
We provide here the prm files and required input files for the Aspect 2-D cases shown in Figures 2 and 3, which are the only cases that are neither included in Steinberger et al. (2023) nor in the Ph.D. thesis of Poulami Roy (2024).
Figure 2 is computed with matteo_4.prm; in this case, the initial temperature is in initial_temp_ascii_2, prescribed (zero) surface velocitites are in vel-top-zero
Figure 3 is computed with matteo_14.prm; in this case, the initial temperature is in in initial_temp_ascii_4b.
In both cases, radial_visc_simple.txt is the radial viscosity structure corresponding to adiabatic temperatures, and the file temp-viscosity-prefactor.txt specifies the lateral viscosity variations due to temperature variations.
We also provide the Routine post_processing_matteo_10km.py for extracting plume temperatures versus depth, written by Matteo Jopke.
Furthermore, we provide csv files for all time steps listed in Tables B1 and B2 and shown in Figures 5-7 of the paper. These data have been used to compute plume temperatures and anomalous mass fluxes, in order to address the question posed in the title of the paper. Files are grouped according to model runs into tar files with the same name. The tables are also provided in the Appendix of this data description. The model files are grouped in .tar files according to the model types: single_plume.tar, 2_10.tar; 2.5_2_10.tar; no_slap.tar)
In order to test the feasibility of density and viscosity models suitable to explain geoid and dynamic topography in West Antarctica, we perform computations of a thermal plume that enters at the base of a cartesian box corresponding to a region in the upper mantle, as well as some whole-mantle thermal plume models, as well as some instantaneous disk models, with ASPECT. The plume models have typically a narrow conduit and the plume tends to only become wider as it spreads beneath the lithosphere, typically shallower than ~300 km. These results are most consistent with a shallow disk model with reduced uppermost mantle viscosity, hence providing further support for such low viscosities beneath West Antarctica.
The data are a supplement to the following article: Steinberger, B., Grasnick, M.-L. & Ludwig, R.,
Exploring the Origin of Geoid Low and Topography High in West Antarctica: Insights from Density Anomalies and Mantle Convection Models,
Tektonika, https://doi.org/10.55575/tektonika2023.1.2.35