Abstract During deglaciations, Earth takes up vast amounts of energy, about half of which heats the global ocean. Thus, ocean heat content (OHC) is a key metric to assess Earth's energy budget. Recent modeling studies suggest that OHC changes not only in response to orbitally driven climate change but is also modulated on millennial timescales by the Atlantic Meridional Overturning Circulation (AMOC). Here, we present the first OHC record for the last four deglaciations using noble‐gas ratios in the EPICA Dome C i…

Ice cores from the Allan Hills (AH) Blue Ice Area, Antarctica, are up to 6 million years of age, providing novel snapshots in time reaching back into the Miocene. However, AH ice core records are often discontinuous, probably caused by a complicated flow behaviour and, so far unknown, history. Deriving a better understanding of the past and current deformation via ice crystal orientation and microstructure analysis will help interpret these precious ice samples. We, therefore, apply a cascade of structural glaciol…

81Kr (t1/2=229 ka) is a valuable isotope for radiometric dating of water and ice with a dating range from thirty thousand to over one million years. It is produced by cosmic rays in the stratosphere, and uniformly distributed in the atmosphere with an isotopic abundance of 81Kr/Kr ~ 1 ×10-12. Based on laser cooling and trapping, the detection method Atom Trap Trace Analysis (ATTA) has enabled 81Kr analysis at the extremely low isotopic abundance levels in the environment. However, it has been a challenge …

<title>Abstract</title> The Pleistocene Epoch is characterized by global cooling and an increase in the intensity and duration of glacial cycles. Regional surface and subsurface ocean temperature records follow distinct trends over this interval, suggesting dynamic changes in zonal and meridional heat transport and ocean circulation. Here we provide a record of global ocean heat content (or mean ocean temperature) over the last 3 million years from ice core noble gas (Xe/Kr) measurements. We find long-term ocean c…

Abstract Recent ice cores from the Allan Hills, a blue ice area in Antarctica, are nearly 3 million years old. These cores extend ice core chronologies, enabling new insight into key climate periods such as the Mid-Pleistocene Transition. The interpretation of these climate records is complex because of the disturbed stratigraphy in this ice. Here, we present a new three-dimensional multitrack electrical conductivity measurement method (3D ECM) to resolve layer structure. We demonstrate this technique on a cumulat…