Tectonic signature on the ice cap surface pattern in Dome C area, East Antarctica
The bedrock morphology in Dome C area in East Antarctica is characterised by the presence of a series of elongated depressions separating ridges, with the Aurora and Concordia trenches representing the major depressions with a length of over 100km. In this area the ice cap reaches a thickness of up...
| Main Authors: | , |
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| Other Authors: | , |
| Format: | Other/Unknown Material |
| Language: | English Italian |
| Published: |
2004
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| Subjects: | |
| Online Access: | http://hdl.handle.net/11567/987271 |
| Summary: | The bedrock morphology in Dome C area in East Antarctica is characterised by the presence of a series of elongated depressions separating ridges, with the Aurora and Concordia trenches representing the major depressions with a length of over 100km. In this area the ice cap reaches a thickness of up to 4000 m, leaving the possibility to have water formation and accumulation at its bottom. Vostok Lake is the largest, most famous among these subglacial depression. The geodynamic scenario responsible for the tectonic origin of these structural depression is not still clear: some Authors hypothesise the existence of an Early Paleozoic regional rifting, others propose a Paleozoic compressional tectonic setting. TheAurora and Concordia trenches can be associated to the Vostok Lake to the West, and together form a set of elongated, roughly N-S to NNW-SSE structural depressions, not perfectly parallel. Therefore, it is reasonable to frame their evolution within a NE-SW trending trans-extensional corridor characterised by left lateral, strike-slip shear, with the depressions associated to faults in horse tail geometry (Cianfarra et al., 2003). The relative young age of the Antarctic Ice Cap, about 38 Ma, compared with the old, Mesozoic age of the former, peneplanised landscape constrains the age of these sharp and fresh structures in Late Cenozoic time. The majority of the observed lakes and depressions are situated in relatively close proximity to ice divides where both the surface slope and ice velocity is small. The presence of this morphology induces variations in the surface texture of the ice cap either due to the movements of the ice sheet on the roughness of the bedrock morphology, and/or to the interaction with active tectonic processes. A series of preferential orientations may relate also to exogenous processes as regional winds. The resulting textural anisotropy of the ice surface can be easily detected from regional scale remotely sensed images. Radarsat mosaic of Antarctica proved a useful tool to ... |
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