Spectral analysis of physical properties of the Prydz Bay sediments, Antarctica for identifying cycles for the last five million years
The ODP Site 1165 is located 400km northwest of Prydz Bay, Antarctica and it contains a high-resolution Plio-Pleistocene sediment record of glacial history and related climate changes. The East Antarctic Ice Sheet (EAIS) has existed for more than 34 Ma. During that time it has fluctuated considerabl...
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| Format: | Text |
| Language: | English |
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2009
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.624.1667 http://www.geophysica.fi/pdf/geophysica_2009_45_1-2_215_valppu.pdf |
| Summary: | The ODP Site 1165 is located 400km northwest of Prydz Bay, Antarctica and it contains a high-resolution Plio-Pleistocene sediment record of glacial history and related climate changes. The East Antarctic Ice Sheet (EAIS) has existed for more than 34 Ma. During that time it has fluctuated considerably and it has been one of the considerable driving forces of climate and global sea level throughout the late Cenozoic era. Evidence of the formation and development of the Antarctic ice sheets comes from variety of sources, including physical properties of the marine sediments. The waxing and waning of ice masses is associated with changes in terrigenous sediment supply. High quality record of physical properties from marine sediments is increasingly collected for paleoclimatic purposes. This study is an example of use of spectral analysis to physical properties including magnetic susceptibility and gamma-ray attenuation porosity/density evaluation (GRAPE) measurements during the last five million years of deposition. The studied interval was sampled every 10 cm and discrete samples were measured for magnetic susceptibility to obtain more prominent dataset with less noise. The results show record of the glacier ice dynamics and its cyclic behaviour due to external (i.e. orbital) forcing. The pronounced expression of the middle Pliocene warm period from 3.15 to 2.85 Ma ago is seen in discrete samples by the elevated magnetic susceptibility values by a factor of two compared to earlier record. Key words: Antarctica, physical properties, ice sheet dynamics, climate change 1. |
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