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| Titel |
Characterizing and tracing the dust sources of Lakes Sihailongwan and Huguangyan Maar in NE and SE China over the past 80 kyrs |
| VerfasserIn |
Shikma Zaarur, Mordechai Stein, Jens Mingram, Yigal Erel |
| Konferenz |
EGU General Assembly 2017
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| Medientyp |
Artikel
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| Sprache |
en
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 19 (2017) |
| Datensatznummer |
250152816
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| Publikation (Nr.) |
 EGU/EGU2017-17703.pdf |
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| Zusammenfassung |
| A major challenge in the field of quaternary paleoclimate lies in reconstructing and
understanding changes in atmospheric circulation and its relation to global and
regional climate patterns. In this study, we use mineralogical, chemical and isotopic
signatures of fine size particles in lake sediments to trace the sources of dust, as a tool to
understand the synoptic patterns in East Asia during the past ∼80 kyrs. The study
focuses on sediments from two maar lakes: Sihailongwan and Huguangyan in NE and
SE China, respectively. These two are ideal for our study; they are hydrologically
confined and do not drain any rivers or streams that introduce additional particle
sources other than the volcanic rims and windblown dust. Sediment cores from both
lakes were obtained by the German-Chinese drilling project (Mingram et al. 2004).
Both cores have been previously dated and their general composition had been
characterized (Mingram et al. 2004, Zhu et al. 2013). To characterize the local signature we
additionally collected sediments from the rim and the vicinity of the lakes. Because we
are interested in windblown particles, we concentrate on fine sediment fraction
(<70μm). The fine particles from Sihailongwan Maar show large variations in the
chemical compositions (e.g. ∼0-9% and 2-8% for CaO and Fe2O3, respectively) and
87Sr/86Sr and ɛNd values of 0.711-0.715 and -2 to -13, respectively. In the ɛNd -
87Sr/86Sr diagram the samples lie between the values of: -3.5 and 0.71113, and 8.3 and
0.71543, suggesting changes in contributions from nearby northeast China and
farther west China deserts, respectively. The fine particles of Huguangyan Maar
resemble tropical soils dominated by Fe and Al oxides. A few abrupt variations in
iron might reflect changes in rain/monsoon intensity or local changes in source
material. Sr and Nd isotope ratios of materials from the lakes’ rim and vicinity
display large variations (87Sr/86Sr and ɛNd values of 0.7042-0.7202 and 6.0 to
-8.8 for, respectively) and form two distinct mixing lines between the local basalt
and two different end members. Isotopic values of core samples fall between the
two lines and likely represent shifts in the relative contribution of each source. |
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