README for AFRP20 models and mask files.

A BOYCE 2020-01-28 (ab2568@cam.ac.uk & https://alistairboyce11.github.io/)

This file contains details of P-wavespeed models and raypath illumination mask to accompany the manuscript:

Boyce, A. Bastow, I.D. Cottaar, S. Kounoudis, R. Guilloud De Courbeville, J. Caunt, E. Desai, S. (2021), AFRP20: New P-wavespeed Model for the African Mantle Reveals Two Whole-Mantle Plumes Below East Africa and Neoproterozoic Modification of the Tanzania Craton, Geochem. Geophys. Geosyst., https://doi.org/10.1029/2020GC009302. 

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The file AFRP20_RF_CR1_MOD.txt is the file containing velocity model parameters for the tomographic model including crustal correction.

AFRP20_RF_CR1 is an adaptively parameterized, global absolute P-wave tomographic model following the methodology of Li et al., (2008). The crustal correction implemented in this model is described in the manuscript and supplementary material. ak135 (Kennett et al., 1995) is used as the global reference model. New data has been added in Africa, so we provide only the African component of the model. While the adaptively parameterized grids at upper mantle depths can be found in the supplementary material of the manuscript, here we provide the model sampled at 0.25x0.25 degrees and 50km depth to facilitate smooth plotting. The 3D grid contains the columns: depth (km), latitude (deg), longitude (deg), dVp (percentage relative to ak135), vp (absolute vp in km/s).

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The file AFRP20_MOD.txt is the file containing velocity model parameters for the tomographic model excluding crustal correction.

AFRP20 is an adaptively parameterized, global absolute P-wave tomographic model following the methodology of Li et al., (2008). No crustal correction is implemented in this model. ak135 (Kennett et al., 1995) is used as the global reference model. New data has been added in Africa, so we provide only the African component of the model. While the adaptively parameterized grids at upper mantle depths can be found in the supplementary material of the manuscript, here we provide the model sampled at 0.25x0.25 degrees and 50km depth to facilitate smooth plotting. The 3D grid contains the columns: depth (km), latitude (deg), longitude (deg), dVp (percentage relative to ak135), vp (absolute vp in km/s).

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The file AFRP20_MASK.txt contains the masked regions used to plot grey shaded areas in the main manuscript. 

Regions sampled by the ray paths added in the AFRP20 models are calculated following the procedure outlined in Section 12 of the supplementary material that accompanies the main paper. The global data set will of course further illuminate the mantle wavespeed structure so this acts to show the areas better resolved using the new data. Regions where the mask is on (i.e. equal to 1) are regions of lower confidence or poor illumination. Regions where the mask is off (i.e. equal to 0) are regions of higher confidence or good illumination. The 3D grid contains the columns: depth (km), latitude (deg), longitude (deg), mask on (1/0).