Variations of the effective elastic thickness reveal tectonic fragmentation of the Antarctic lithosphere

To this day, little is known about thermal and Theological properties of the Antarctic lithosphere. We derive the effective elastic thickness T-e as a proxy for these parameters by using ice thickness, bedrock topography and a combination of new satellite and high resolution terrestrial gravity data. Cross-spectral analysis based on the fan wavelet technique was employed to calculate T-e variations by means of admittance and coherence techniques. Our results confirm a clear tectonic division of Antarctica with predominantly high values in East Antarctica (EANT) (T-e similar to 60-80 km) and low values in West Antarctica (WANT) (T-e similar to 5-20 km). For the Transantarctic Mountains separating these provinces, we found T-e to be around 10 km along the whole chain which is comparable to WANT. Apart from this general division, we found fragmentation of the lithosphere within these provinces. Especially EANT doesn't represent a single lithospheric block but shows strong variations of T-e. The highest values are found around the Aurora Subglacial Basin (T-e similar to 90 km) and in Dronning Maud Land (T-e similar to 80 km). The minimum value of T-e within EANT (similar to 15 km) is found in the Lambert Graben. Such a low value can be associated with active rifting in the Permian-Triassic, strong localized erosion or possibly the effect of a Cenozoic mantle plume. According to the coherence calculations, the weak zone extends to the Gamburtsev Subglacial Mountains (GSM), showing a distinct decrease of T-e to 25-30 km. Thus, this weak channel divides the previously mentioned strong blocks. However, the admittance analysis gives relatively high values (T-e similar to 70 km) for the GSM. Based on the analysis of the wavelength-dependent admittance and coherence results and misfits for several principal locations, we give some preference to the coherence based values. (C) 2017 Elsevier B.V. All rights reserved.