Mesozoic to recent evolution of intraplate stress fields under multiple remote stresses: The case of Signy Island (South Orkney Microcontinent, Antarctica)
Published:January 01, 2013
A. Maestro, J. López-Martínez, F. Bohoyo, 2013. "Mesozoic to recent evolution of intraplate stress fields under multiple remote stresses: The case of Signy Island (South Orkney Microcontinent, Antarctica)", Antarctic Palaeoenvironments and Earth-Surface Processes, M. J. Hambrey, P. F. Barker, P. J. Barrett, V. Bowman, B. Davies, J. L. Smellie, M. Tranter
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Palaeostresses inferred from approximately 3200 brittle mesostructures measured at 43 sites in Signy Island show a stress field characterized by compressional, strike-slip and extensional stress states. There is a dominant NW–SE horizontal compression direction as well as three (NNW–SSE, WNW–ESE and ENE–WSW) secondary σ1 horizontal stress directions. Orientation of σ3 shows a main mode trending NW–SE together with secondary north–south and NE–SW extensional stress directions. The NNW–SSE horizontal compression is consistent with the stretching–shearing direction defined from the fold-axis trend. This is owing to a subduction-related tectonic regime during early to middle Jurassic times. In middle Jurassic/early Cretaceous times, the tectonic regime changes to extensional with north–south extensional stress directions. The early processes of subduction of the northern sector of the Weddell Sea oceanic crust below the South Orkney Microcontinent, from the Paleocene until the middle Miocene, is related to the σ1 direction WNW–ESE to NW–SE. The spreading of Powell Basin took place from the late Eocene to the early Miocene and is the cause of east–west and NE–SW extensional processes in the southern South Orkney Microcontinent. Finally, the NW–SE σ3 direction is related to the current left-lateral strike-slip movement between the Scotia and Antarctic plates.
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Antarctic Palaeoenvironments and Earth-Surface Processes
The volume highlights developments in our understanding of the palaeogeographical, palaeobiological, palaeoclimatic and cryospheric evolution of Antarctica. It focuses on the sedimentary record from the Devonian to the Quaternary Period. It features tectonic evolution and stratigraphy, as well as processes taking place adjacent to, beneath and beyond the ice-sheet margin, including the continental shelf.
The contributions in this volume include several invited review papers, as well as original research papers arising from the International Symposium on Antarctic Earth Sciences in Edinburgh, in July 2011. These papers demonstrate a remarkable diversity of Earth science interests in the Antarctic. Following international trends, there is particular emphasis on the Cenozoic Era, reflecting the increasing emphasis on the documentation and understanding of the past record of ice-sheet fluctuations. Furthermore, Antarctic Earth history is providing us with important information about potential future trends, as the impact of global warming is increasingly felt on the continent and its ocean.