Prof. Nicholas Christie-Blick
Earth Institute Contact: Prof. Nicholas Christie-Blick
Additional External Researchers:
Steve Pekar, Steve Goldstein, Safiya Hassan
Stratigraphic and sedimentological data from the lower Miocene Moghra Formation (~20-16 Ma) of northwestern Egypt reveal well defined cyclicity that we hypothesize relates to sea-level change induced by the growth and decay of the East Antarctic ice sheet. Preliminary data suggest that it may be possible to place additional constraints on the changing depositional environment by analyzing the distribution in the sediments of benthic (bottom-dwelling) calcareous microfossils called foraminifers; and to use those fossils, along with planktonic (free-floating) foraminifers and calcareous macrofossils to date the sediments by measuring strontium isotopes. The strontium isotopic ratio of seawater is known to have changed appreciably during Oligocene and Miocene time, offering an excellent way to obtain high-resolution ages on marine carbonates. The early Miocene sea-level record is already quite well known. So the deposits in Egypt provide an independent test of that record and of ideas about how sea-level change modulates shallow marine sedimentation.