Abstract:

Based on structural analysis and available geochronological data, four principal episodes of deformation (D1-D4) are distinguished in the Reinbolt Hills of the eastern Amery Ice Shelf, East Antarctica. The D1 deformation took place at >970 Ma and is responsible for the formative stage of the WE-trending regional gneissosity in metamorphic rocks. The D2 deformation is characterized by the EW-trending folds with steep axial plane occurred in orthogneisses during the early Neoproterozoic. Tight asymmetrical folds and low-angle stretching lineations developed on the shear foliations of the rock during this period. The D3 deformation is marked by high-angle normal faults resulted from the early Cambrian tectonic uplift. The emplacement of charnockites in the Jennings Promontory may also be related to this deformational event. The D4 deformation is responsible for the NE-NNE-trending fracture cleavages in the Reinbolt Hills and Jennings Promontory probably formed during the late Mesozoic to Cenozoic. The D1 and D2 deformational episodes in the Reinbolt Hills could be comparable with those in the northern Prince Charles Mountains, suggesting that the Rayner Complex might be extended eastward to the Reinbolt Hills. Taking into account the occurrence of the early Cambrain (i.e. Pan-African) charnockites in the Jennings Promontory, we infer a nearly SN-trending tectonic boundary separating the Reinbolt Hills and Jennings Promontory. Therefore, the Prydz belt might not extend westward to the Lambert terrane, but southward to the Grove Mountains and Gamburtsev Sub-glacial Mountains.

Key words: Early Cambrain, the eastern Amery Ice Shelf, tectonic deformation, Gamburtsev Sub-glacial Mountains