Late glacial to Holocene climatic changes in the Northern Red Sea based on a multi-proxy reconstruction: The influence of North Atlantic climate, sea level, and monsoonal forcing
by
Helge W. Arz
Fachbereich Geowissenschaften, Universität Bremen
Coauthors: Jürgen Pätzold, Peter J. Müller, Mustafa O. Moammar, Gerold Wefer

We present a ¹⁴C-AMS dated, high-resolution marine paleoclimate record from the northern Red Sea from a sediment core retrieved during RV METEOR cruise M44/3 in spring '99 off the southern tip of the Sinai Peninsula. Because of its restricted, desert surrounded location, the northern Red Sea suffered extreme oceanographic changes in the past that resulted in an amplification of the paleoclimate signals in the marine records. Since continuous high-resolution paleoenvironmental data from the northern Red Sea region are still rare, our data provide an important link to, e.g., climate reconstructions from northeast Africa, the Mediterranean, and the Dead Sea.

Past hydrographic conditions in the northern Red Sea were reconstructed by means of stable oxygen isotope composition on tests of shallow dwelling planktic foraminifera, pteropods, and benthic foraminifera. Sea surface temperatures (SST) were estimated with the alkenone paleothermometry method and subsequently used to extract the salinity signal from the delta¹⁸O values. Changes in sediment composition were additionally determined by means of MultiSensorCoreLogger and XRF core-scanner measurements.

SST's during the last 22 kyrs in the northern Red Sea were strongly affected by the high-latitude Northern Hemisphere climate, with particularly strong coolings during the Heinrich 1 event and the Younger Dryas chron. LGM temperatures were about 4°C cooler and surface salinity exceeded at that time about 50‰. Due to the restricted seawater exchange with the Indian Ocean through the shallow Strait of Bab el Mandeb, Red Sea salinity is particularly sensitive to changes in global sea level. Reconstructed paleosalinities clearly indicate a freshening of the surface waters associated with the melt-water peaks MWP1a and MWP1b. Vertical delta¹⁸O gradients are also increased during these phases.

With the onset of the monsoon maximum at around 10 kyrs, surface salinities reached an absolute minimum of about 37‰, i.e. 3‰ less than today. Concordantly, proxy data reflecting the terrigenous input - most probably eolian dust - reach minimum values. The monsoon-related low salinity phase ends abruptly around 6, 500 cal yr B.P., that is 1 to 2 kyrs earlier than in tropical and subtropical Africa, which is in good agreement with the paleoclimate record from the Gulf of Aqaba.

Date received: March 28, 2001

Copyright © 2001 by the author(s). The author(s) of this document and the organizers of the conference have granted their consent to include this abstract in Atlas Conferences Inc. Document # cagc-47.