Schwikowski Margit
Radiocarbon dating of ice from a Kilimanjaro plateau glacier
Project Number: 200020_144388
Research Areas:
Disciplines:
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| climatology, atmospheric physics, aeronomy |
| hydrology, limnology, glaciology |
Keywords:
radiocarbon, glacier ice, carbonaceous particles, dating, kilimanjaro
Abstract:
LeadIce samples from the Northern Ice Field of Mount Kilimanjaro will be dated with a new radiocarbon method to resolve the controversy if the near extinction of the ice on Kilimanjaro is unprecedented over the last 11’700 years or has occurred several times throughout the Holocene. IntroductionHigh-alpine ice cores from mid- and low-latitude glaciers and ice caps provide regional climate signals in areas inhabited by the majority of the world’s population. Interpreting the information contained in natural climate archives requires a precise chronology. For high-alpine ice cores there is a lack of an appropriate dating tool for the lowermost section since strong ice flow induced layer thinning limits counting of annual layers in the best case to a couple of centuries and is not suitable for the oldest and deepest ice. Glacier flow is dominated by the small-scale geometry of bedrock, resulting in a strongly non-linear depth-age relationship over time, which cannot be fully resolved using physical ice flow models. Under these circumstances, radiocarbon analysis using the insoluble organic carbon aerosol fraction can provide an absolute date.Aims of the projectThis novel radiocarbon approach will be applied on 48 ice samples collected from the Northern Ice Field during our 2011 expedition to Mount Kilimanjaro to help resolving the current debate about the age of the Kilimanjaro plateau glaciers. Palaeoclimate reconstructions based on six ice cores, assigned a basal age of 11’700 years. Another study claims that plateau glaciers on Kilimanjaro are subject to recurring cycles of waxing and waning controlled primarily by atmospheric moisture. An absence of the ice bodies was reconstructed for the period around 850 years ago.ImplicationsThe Kilimanjaro ice fields are subject to rapid areal shrinkage and thinning. They are expected to disappear within the next few decades. Resolving the controversy if the near extinction of the ice on Kilimanjaro is unprecedented over the last 11’700 years or has occurred several times throughout the Holocene might have wide implications for the understanding of the full range of natural climate variability in the tropics.
Source of Information: NF Import 2014
Last update: 5/23/16
Source of data: ProClim- Research InfoSystem (1993-2024)
Update the data of project: CH-200020_144388
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