Сохранность климатического сигнала в слоях древнего льда в районе Купола В (Антарктида)

Translated title of the contribution: PRESERVATION OF THE CLIMATIC SIGNAL IN THE OLD ICE LAYERS AT DOME B AREA (ANTARCTICA)

Алексей Анатольевич Екайкин, Владимир Яковлевич Липенков, Кирилл Борисович Чихачев

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Abstract

In this work we have presented the results of numerical modeling of the age and temperature distribution in ice layers at Dome B site (79,02° S, 93,69° E, altitude 3807 m a.s.l., ice thickness about 2.5 km), located 300 km to the west from Russian Antarctic station Vostok. Dome B is situated on the onset of the ice flow line passing through deep borehole 5G, and is considered as one of the most promising places to search for and to study the Easth’s oldest ice with the age of up to 1.5 Ma. According to our calculations, all realistic scenar‑ ios show the ice age at 60 m above the ice base to be considerably older than 1 Ma, and the glacier base tem‑ perature is well below the pressure melting point (−1.8 °С for pressure = 23 MPa). For the most likely sce‑ nario (accumulation rate 1.8 g/(cm 2 year), effective ice surface temperature −64 °С and geothermal heat flux 60 mW/m 2) the ice age is 1.4 Ma and the basal temperature is about −13 °С that is close to the earlier pre‑ dictions from a 2D‑model. Maximum estimate of the «diffusion length» in the old ice (for the scenario in which the basal temperature reaches the melting point, and in which 30% of «excess diffusion» is taken into account) is 5.2 cm. In 1.4 Ma‑old ice a 40‑ka climatic cycle is squeezed into a 290‑cm thick ice layer. For this ratio of wave length and diffusion length the climatic signal attenuation (ratio between the signal amplitude after and before the diffusive smoothing) is 0.6%. Thus, due to the relatively low ice temperature here we may expect a nearly undisturbed climatic curve in the old ice core that will be drilled one day at Dome B. At the same time shorter oscillations with the wavelengths of < 1500 years will be totally erased by diffusion.

Translated title of the contributionPRESERVATION OF THE CLIMATIC SIGNAL IN THE OLD ICE LAYERS AT DOME B AREA (ANTARCTICA)
Original languageRussian
Pages (from-to)5-13
Number of pages9
JournalЛед и Снег
Volume61
Issue number1
DOIs
StatePublished - 2021

Scopus subject areas

  • Global and Planetary Change
  • Water Science and Technology
  • Geochemistry and Petrology
  • Earth-Surface Processes

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