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Titel |
Tectonic fragmentation of the Antarctic lithosphere as revealed by the analysis of effective elastic thickness variations |
VerfasserIn |
Carina Haeger, Bo Chen, Mikhail K. Kaban, Alexey G. Petrunin |
Konferenz |
EGU General Assembly 2017
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Medientyp |
Artikel
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Sprache |
en
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Digitales Dokument |
PDF |
Erschienen |
In: GRA - Volume 19 (2017) |
Datensatznummer |
250144903
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Publikation (Nr.) |
EGU/EGU2017-8781.pdf |
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Zusammenfassung |
In this study, we derive the effective elastic thickness Te as a proxy for the lithospheric
strength and thermal state by using ice thickness, bedrock topography and a combination of
new satellite and high resolution terrestrial gravity data. Cross-spectral analysis methods
based on the fan wavelet technique were employed to calculate both admittance and
coherence based values of Te. To this day, little is known about the thermal and rheological
properties of the Antarctic lithosphere. Those properties are important to understand ongoing
tectonic processes and the behaviour of the Antarctic ice shield. Te variation shows, that
Antarctica can be divided into two distinct provinces, with high values in EANT
(Te ∼60-80 km) and low values in WANT (Te ∼5-20 km). For the Transantarctic Mountains
separating these provinces, we found Te to be around 10 km and thus comparable to western
Antarctic values. Apart from this general division, we found fragmentation of the lithosphere
within these provinces. Especially EANT is not homogeneous in lithospheric strength but
shows strong variations. The highest Te values are found around the Aurora Subglacial
Basin (up to ∼90 km) and in Dronning Maud Land (up to ∼80 km). Dividing these
provinces is a zone of relatively low Te with its minimum of ∼15 km in the Lambert
Graben. According to coherence based calculations, this weak zone extends into the
Gamburtsev Subglacial Mountains showing a distinct decrease of Te to 25-30 km. The
admittance analysis gives relatively high values (∼70 km) for this region. Based on the
wavelength-dependent admittance and coherence results and misfits for several principal
locations and since the admittance estimations could be significantly biased by internal
density heterogeneity of the lithosphere, as already pointed out in several previous
studies, we give some preference to the coherence method predicting reduced Te. |
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