Variations of the effective elastic thickness reveal tectonic fragmentation of the Antarctic lithosphere
| Autor: | Mikhail K. Kaban, Bo Chen, Carina Haeger, Alexey G. Petrunin |
|---|---|
| Rok vydání: | 2018 |
| Předmět: |
geography
geography.geographical_feature_category Rift 010504 meteorology & atmospheric sciences Bedrock Geophysics Structural basin 010502 geochemistry & geophysics 01 natural sciences Mantle plume Graben Tectonics Lithosphere Cenozoic Geomorphology Geology 0105 earth and related environmental sciences Earth-Surface Processes |
| Zdroj: | Tectonophysics |
| Popis: | To this day, little is known about thermal and rheological 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 ~ 60–80 km) and low values in West Antarctica (WANT) (T e ~ 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 ~ 90 km) and in Dronning Maud Land (T e ~ 80 km). The minimum value of T e within EANT (~ 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 ~ 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. |
| Databáze: | OpenAIRE |
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