Dating and investigating climate variability at high resolution in the deep portion of the TALDICE ice core
Ice cores are long cylinders extracted from ice sheets containing information about past environmental and climatic conditions. The TALDICE ice core is a 1620 m depth core drilled at Talos Dome, in East Antarctica. Several previous studies focused on dating this core and an age scale has been define...
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Other Authors: | , , , , , , |
Format: | Doctoral or Postdoctoral Thesis |
Language: | French |
Published: |
HAL CCSD
2022
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Subjects: | |
Online Access: | https://theses.hal.science/tel-04536614 https://theses.hal.science/tel-04536614/document https://theses.hal.science/tel-04536614/file/108657_CROTTI_2022_archivage.pdf |
Summary: | Ice cores are long cylinders extracted from ice sheets containing information about past environmental and climatic conditions. The TALDICE ice core is a 1620 m depth core drilled at Talos Dome, in East Antarctica. Several previous studies focused on dating this core and an age scale has been defined only until 1438 m depth at an age of about 150,000 years ago, limiting the past climate reconstructions to the last climatic cycle. This thesis focuses on the poorly explored deep portion of the core below 1438 m depth. In the first part of the thesis, the new TALDICE isotopic measurements in both ice and gas matrixes below 1438 m are used to build the final TALDICE deep1 ice/gas age-depth relationship with the application of the IceChrono1 model. The chronology for the deeper part of the core is here defined until 1548 m depth and extends the climatic record back to 343,0000 years ago. The second part of this thesis is centred on the interpretation of the unique TALDICE isotopic signal during past interglacial periods. The proposed interpretation indicates that the interglacial anomalies in the isotopic record have been produced by the lowering of the Talos Dome site elevation due to ice loss and inland retreat of the Wilkes Subglacial Basin grounding line. The third and last part of this work focuses on the development of the argon dating technique called “copper method”, with the aim of reducing the amount of ice employed. The novel methodology has been tested on 11 TALDICE samples. The “copper method” results are validated by comparing them with the published TALDICE chronologies (AICC2012 and TALDICE deep1) and with 8 neighbouring samples dated with the well-established argon dating “getter method”. Les carottes de glace sont de longs cylindres extraits des couches de glace contenant des informations sur les conditions environnementales et climatiques passées. La carotte de glace TALDICE est une carotte de 1620 m de profondeur forée à Talos Dome, en Antarctique de l'Est. Plusieurs études antérieures se sont ... |
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