Stable
isotopes (ð18 O, ð13 C) and geochemical data of some travertine
deposits were used to constrain the paleoclimatic and
paleoenvironmental conditions of southern Egypt during late
Pleistocene. Travertine samples were collected from Kurkur Oasis and
Wadi Dungul (Western Desert) and Wadi Mubarak in the Eastern Desert.
The studied travertine samples are generally fragile, fine grained,
white, yellow or brown in color of submeter to several meters in
thickness. They unconformably overlie Eocene Limestone in the
Western Desert and Pre-Cambrian Basement rocks in the Eastern
Desert.
The U/Th dating of these deposits clusters around 160-180, 255-284
and >300 to 450 Ka. The isotopic composition of the travertine
deposits is nearly similar despite the large difference in age.
location and depositional mode.
Geochemical composition of the studied travertines indicate that
they are almost composed of low Mg calcite with traces of elements
easily incorporated within the calcite latttice such as Mg2+ , Fe
and Mn2+. The MgCO3 content of the studied travertine samples ranges
from 0.36 to 0.46 mol% with an average value of 0.46%., which is
typical for calcite precepitated from through-flowing meteoric
freshwaters
Field, petrographical, geochemical and isotopic studies reveal that
the deposition of the travertine deposits occurred during
interglacial wet conditions accompanied by high water table,
alkaline spring recharge and considerable vegetation cover. The
ð18O
values of the travertines indicate that the water-producing
travertine is similar to the fossil groundwater of the Western
Desert of Egypt which implies distant Atlantic sources. The present
study also concludes that southern Egypt was affected by intensive
summer Monsoon climate during middle and late Pleistocene.
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