Magnetotelluric data and resistivity models from deep Earth investigations in East Antarctica

Title:Magnetotelluric data and resistivity/viscosity models for "Magnetotelluric Constraints on Mantle Viscosity Beneath East Antarctica: An Integrated Geophysical Approach" Authors:Manassero, M. C.; Selway, K.; Reading, A.; Askey-Doran, N.; Ramirez, F.; Stål, T.; Peacock, J.; Aitken, A. Description: This repository contains the magnetotelluric (MT) data, electrical resistivity models, and derived upper-mantle viscosity models presented in Manassero et al. (in review), IMagnetotelluric Constraints on Mantle Viscosity Beneath East Antarctica: An Integrated Geophysical Approach. The data were collected during the Denman Terrestrial Campaign (2022–2025) at eight long-period MT stations (A18, BHIL, DF5, DF6, DF7, RAID, TR5, V5) spanning the Aurora Subglacial Basin and Queen Mary Land, East Antarctica. The repository is organised into the following components. 1. Magnetotelluric transfer functions.Processed and rotated MT impedance tensors and tipper functions for all eight stations, in EDI format, covering periods from 0.0016 to 6000 s. Data were acquired with Phoenix MTU-5C loggers and MTC-150/MTC-155 induction coils, processed in EMpower v2.2 using robust remote-reference processing, and rotated into a geographic (north-aligned) reference frame by the local magnetic declination. Dat, file include the data and error estimates used for ModEM inversion (periods 0.05–6000 s). Raw time series are archived separately at https://doi.org/10.25914/rr0p-yb26. 2. Three-dimensional resistivity models.The eight best-fitting 3D resistivity models (Models 1–8) obtained with ModEM, together with their starting models, prior models, and model covariance/regularisation settings. RMS misfits range from 1.49 to 1.74. Each model file includes the inversion mesh (50 × 86 × 60 cells; 10 km horizontal cells in the core; vertical layers from 100 m at the surface to a maximum depth of 3760 km). Topography and bathymetry follow the ETOPO 2022 v1 global relief model; the ice layer is 10⁵ Ω·m and the ocean 0.3 Ω·m. 3. One-dimensional resistivity profiles.Resistivity–depth profiles extracted beneath each station from each of the eight 3D models (0–300 km), used as the conductivity input to the viscosity workflow. Format CSV 5. Geotherms and viscosity models.Temperature, water-content, and viscosity profiles beneath each station, derived following the workflow of Ramirez et al. (2022). Two seismically derived geotherms are provided: (i) a steady-state conductive geotherm (HCA) constructed with the Hasterok & Chapman (2011) formulation using the Moho and LAB depths of An et al. (2015); and (ii) the probabilistic thermomechanical geotherm of Hazzard et al. (2023), derived from the ANT-20 velocity model. Water content is inferred from the MT-derived conductivity; viscosity is computed with a composite olivine (diffusion + dislocation) rheology for harzburgite composition, under low- and high-differential-stress assumptions. Format CSV Third-party datasets used but not redistributed here.The following external datasets are used in the analysis and figures and are available from their original sources (cited in the paper), not redistributed in this repository: the ANT-20 seismic velocity model (Lloyd et al. 2020); the AN1-S velocity model and An et al. (2015) temperature/LAB model; the Hazzard et al. (2023) thermomechanical model; the EM3D_L 3D viscosity field of Wan et al. (2022), as applied by Gomez et al. (2024); the Ivins et al. (2023) viscosity estimates; BedMachine v3 (Morlighem et al. 2022); and the ETOPO 2022 v1 global relief model (MacFerrin et al. 2025). Software.Processing and modelling used EMpower v2.2, ModEM (Kelbert et al. 2014), MTPy, and MATLAB R2023b. Viscosity calculations follow Ramirez et al. (2022) and Pide (Ozaydin et al. (2025) used for the conductivity-to-water step. Citation.If you use these data or models, please cite both this repository and the associated paper: Manassero, M. C., et al. (in review). Magnetotelluric Constraints on Mantle Viscosity Beneath East Antarctica: An Integrated Geophysical Approach. Journal of Geophysical Research: Solid Earth. Funding.Australian Research Council Special Research Initiative, Australian Centre for Excellence in Antarctic Science (SR200100008); Denman Terrestrial Campaign projects 4547, 4530, 4630. Instrumentation provided by the GRIT instrument pool (AuScope). License. CC BY 4.0