1Institut of Isotope Geochemistry and
Abstract. Determining the sources and pathways of atmospheric dust4 remains a difficult problem. To address this problem, the radiogenic isotopes5 composition of dust found within ice-core has been determined and used as6 a dust source tracer. The measured ice core record is a short, high resolu-7 t...
| Main Authors: | , , , , |
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.551.9364 http://www.polar-research.ch/downloads/lupker2.pdf |
| Summary: | Abstract. Determining the sources and pathways of atmospheric dust4 remains a difficult problem. To address this problem, the radiogenic isotopes5 composition of dust found within ice-core has been determined and used as6 a dust source tracer. The measured ice core record is a short, high resolu-7 tion (yearly to seasonal) time series of Sr and Nd isotopic composition of both8 dust and ice from the ∼128m to 132m section of the Dye-3 (88) ice core in9 Greenland. Hf isotopic composition was also measured for three of the dust10 samples as a complementary tracer of dust origin, the first direct measure-11 ment of Hf in paleo-atmospheric dust. Measured Nd and Sr isotopic com-12 position of the dust compared to literature potential source area (PSA) data13 (<5µm size fraction) shows variability of the potential source area on short14 time scales. Asia is identified as one potential source to the Greenland dust15 load; the primary contributions are from the Taklimakan desert, Gobi desert16 and the Ordos Plateau. Another dust source mixing with the Asian dust is17 invoked to explain the variability in the isotopic composition of the ice core18 dust, but this source area has not been identified because of the lack of ad-19 equate sampling of PSAs or Hf analyses. The radiogenic isotopes within the20 ice fraction is found to be of oceanic origin; the 87Sr/86Sr values, close to sea-21 water, and Nd variations are decoupled from dust composition. Isotopic com-22 position of these elements in ice is thought to be derived from sea salts or23 sea ice brine and measurements of Sr and Nd could constitute a valuable tool24 for climate reconstructions.25 |
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