OPTICAL STIMULATED LUMINESCENCE AGE ESTIMATES
OF QUATERNARY AEOLIANITES AND PALEOSOLS, NW COAST, EGYPT
HESHAM M. ELASMAR
Dept. Geology, Damietta Fac. Sciences, Damietta, 34517, Egypt.
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The aeolian sediments, NW coast of Egypt, together with marine deposits and paleosols form successive ridges parallel to shoreline, Chemically precipitated CaCO3 within marine deposits and aeolianites, land snails within paleosols, and marine shells were dared using 14c, U-series and aminoacid geochronology (AAG).
In the present study, additional optical stimulated luminescence (OSL) age estimates have been used in order to verify the ages derived from CaCO3 with others
derived from detrital components of the aeolianites. The OSL ages of the aeolianites and paleosols of the Coastal ridge and ElMax Abu Sir ridge are in agreement with ages derived from the other dating techniques. They belong to coastal dunes related to still-stands of sea level during Holocene (ab, 5000 B.P.) and the Last Interglacial, OIS 5c/5a (108±17ka). The paleosols and calcretes at the N flanks of ElMax Abu Sir and Gebel Maryut ridges appear to have derived their material from the wind-blown dust during and climate between 70-24ka, and developed later with the advent of Holocene rains.
The aeolianites at Gebel Maryut ridge and paleosols at top of Khasham ElIsh ridge show controversial ages with large errors and appear in disagreement with the previous dates. This is attributed either to the problem of detecting zero point of bleaching in relation to weathering and reworking of detrital materials, the decay. series of radioactive parent materials, water content, or post depositional changes. However, still the ages indicate Middle Pleistocene age.
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