48 The Impact of Climate Change on Barrier Island-Backbarrier Systems

Monday, 15 March 2010
1:30 PM - 5:35 PM
Liberty A

THE ROLE OF SEA LEVEL AND BAY INFILLING IN THE CLOSING OF AN ANCIENT EGYPTIAN HARBOR

Paper number: 48-6
Program: Theme Sessions
Time: 2:55 PM – 3:15 PM

Authors

Abstract

Archeological investigations along a carbonate / conglomerate terrace located 600 m landward of the Red Sea coast in Egypt have uncovered the existence of an ancient (~4 kya) Egyptian harbor, a site from which seafaring ships departed for trade routes along the African Red Sea coast. Nearly 10 years of excavations at Mersa / Wadi Gawasis, a Middle Kingdom Egyptian site, have documented evidence for occupation on the top and at the base of the terrace, including temporary shelters, rock-cut caves, ceremonial structures, and industrial areas for metal working.

Ground penetrating radar, sediment coring, malacological and foraminiferal studies, radiocarbon dates, and rheological models demonstrate that the wadi bed adjacent to the terrace was once an open, protected bay. The base of the corraline / conglomerate terrace consists of a narrow coral-beach rock platform (dated at ~3500 BP) presently buried by anthropogenic, eolian, and colluvial sediments. Ubiquitous medium-fine wadi sediments underlie and extend beyond the beach rock. Malachological analyses, foraminifera distributions, radiocarbon dates, and sedimentological data indicate that these sediments were deposited in a protected tidal lagoon receiving infrequent freshwater inputs. Wave-cut notches along the seaward shoreline confirm a site-specific rheological model for the northern the Red Sea that indicates a sea-level highstand (~1 m above present MHW) during or immediately prior to occupation. Late during the period of occupation, the lagoon began to close as equatorial siphoning forced a regional sea-level fall while at the same time, riverine discharge through the wadi processes were infilling the bay at rates on the order of .25 cm/year.