Satellite Gravity Constraints on the Antarctic Moho and Its Potential Isostatic Adjustments

Abstract

Geophysical surveying is a principal tool for investigating the poorly understood Antarctic lithosphere south of 60 o S, where the region's remoteness, harsh environmental conditions, and almost complete cover of snow, ice, and seawater severely limit access to the crustal geology (e.g.

Gravity‐Derived Antarctic Crustal Thickness Based on the Gauss‐FFT Method

“…In the following, we compare our results with previously published available models of Moho depth in Antarctica (Figure 8), obtained by various methods, including surface wave tomography (An et al, 2015), integrated geophysical-petrological approach (Pappa, Ebbing, Ferraccioli, & van der Wal, 2019) and joint inversion of seismic and satellite-derived gravity data (Zhang et al, 2020). A data cap is located at the South Pole in Zhang et al's model due to the satellite orbit inclination, and the Antarctic continent is fully covered in the reminder of the models.…”

“…Gravity data seem to offer an alternative pathway to recover the crustal thickness across the entire Antarctic continent since they have one important advantage in their continental‐scale coverage. To achieve this purpose, various models of crustal thickness over Antarctica based on the theory of gravity inversion have been investigated and have achieved a certain degree of progress in the lateral resolution of estimated models (Block et al., 2009; Chisenga et al., 2019; Llubes et al., 2018; O’Donnell & Nyblade, 2014; Pappa, Ebbing, & Ferraccioli, 2019; Zhang et al., 2020). Larger improvements are still needed because the satellite‐derived gravity model they use lacks terrestrial surveyed gravity data.…”

New Magnetic Anomaly Constraints on the Antarctic Crust

“…They overlie crust that possibly extends into southcentral Australia, where the enhanced crustal magnetization may involve magmatic contributions from giant meteorite impact in a normal‐polarity geomagnetic field at ca. 260 Ma and the subsequent Mesoproterozoic rifting of Australia from East Antarctica (Kim & von Frese, 2017; von Frese et al., 2009; Zhang et al., 2020). The inferred impact also may have produced the putative 500‐km diameter Wilkes Land subglacial meteorite basin cra33 [70°S, 120°E] in Figures 1 and 2 , and triggered the end‐of‐Permian activation of the antipodal Siberian traps and the Earth's greatest mass extinction.…”

“…However, the correlation coefficient between them of CC(A,B) = 0.64 indicates that the Swarm mission captured slightly less than 41% of the regional near-surface surveyed anomalies with the differences given in Figure 7c. Grikurov and Leychenkov (2012) and Zhang et al (2020). Table 1 alphabetically lists the feature abbreviations and Table 2 describes the legend.…”

“… Crustal geology of the Antarctic south of 60°S inferred from outcrop, drilling, and geophysical observations as modified from Grikurov and Leychenkov (2012) and Zhang et al. (2020). Table 1 alphabetically lists the feature abbreviations and Table 2 describes the legend.…”