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| Titel |
Short-term level rises during the Lake Lisan desiccation - possible correlations to volcanic eruptions |
| VerfasserIn |
Revital Bookman, Sagi Filin, Shmuel Marco |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250038138
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| Zusammenfassung |
| Short-term decrease in global temperature in response to volcanic eruptions is known from
modern events. The eruption of Mount Pinatubo (June, 1991) led to air temperature anomaly
throughout the Middle East and resulted in an ecological response and coral death in the Red
Sea (Genin et al., 1992). The following winter was characterized by above-average
precipitation in the Dead Sea drainage area, which resulted in changes in the lake water
column structure and anomalous biological productivity. A 2-m level rise interrupted the
dramatic partly-anthropogenic Dead Sea level-drop. These unusual limnological conditions
were also associated with the development of a massive levelled terrace on the lake
shores.
The modern shore terraces and similar geomorphic features left during the desiccation of
Lake Lisan on the margins of the Dead Sea Basin were analyzed using airborne laser
scanning (LiDAR), which provides three-dimension geometry with high level accuracy, high
resolution, large extent, and coverage of inaccessible areas, all leading to unprecedented level
of surface detail. Preliminary results identified about 13 shore terraces on the basin’s
escarpment along Mineral Beach. These terraces were developed during the transition from
the Last Glacial Maximum Lake Lisan high-stands to the Holocene low-stands between
14,700 years BP and 13,800 BP based on the Lake Lisan level curve (Bartov et al.,
2003).
We suggest using the modern analogue of Dead Sea level rise during the winter of 1991-92 as
an indicator for climatic respond to major volcanic eruptions, like the Pinatubo, in the past.
The steep topography and fast Lake Lisan retreat favoured the preservation of the terraces
that record the short-term, perhaps even annual, level rise events. The range of terrace height
is 1 - 6.5 m and using the Dead Sea Basin hypsometric curve the corresponding
volumes of freshwater inputs required for the level rises are ~ 1.9 - 13.7 Ã 109
m3.
Evidence for major paleo-eruptions is embedded in the GISP2 ice core record as atmospheric
SO4 concentration peaks (>75 ppb). Using the Greenland ice record, the number of events
and their magnitude is correlated with high consistency (R2=0.8) to the Lake Lisan
desiccation terrace record. Hence, Lake Lisan shore terraces record provides useful linkage to
global scale teleconnection atmospheric information. We further plan to use atmospheric
simulations to quantify the short-term climatic effect of volcanic eruptions on a regional
scale. |
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