Research project

Project fact sheet

Late Miocene geochemical record from the paleo-Equatorial Pacific region (IODP Expedition 320)

Project researcher(s): 
Anna Joy Drury
Project supervisor(s): 
Dr C├ędric M. John
October, 2010 - September, 2013


Following the permanent establishment of the East Antarctic ice sheet in the middle Miocene, the Earth's climate entered a relatively stable mode punctuated by dramatic events in the late Miocene (~11-5 Ma). Carbonate productivity in the Pacific and Caribbean oceans was dramatically reduced at the middle-late Miocene transition (the "Carbonate Crash"), a factor attributed to changes in ocean circulation. Later, during the Messinian, the Mediterranean Sea became partly or totally isolated from the Atlantic ocean, resulting in partial evaporation of the Mediterranean basin and the formation of extensive evaporite deposits (the "Messinian Salinity Crisis").Both the Carbonate Crash and Messinian salinity crisis are related to ocean circulation, and for the salinity crisis most likely to falling sea-level as high-latitude ice volume increased.

In this project, we aim at producing high-resolution records based on sediments recovered by IODP Expedition 320 in the Equatorial Pacific region. Our approach is to focus on generating high-resolution oxygen isotopes record from benthic foraminifers, and to pair these records with temperature records from Mg/Ca. By doing this, we aim at reconstructing the stable isotopic composition of seawater, which reflects ice volume and by extension sea-level. 

The records generated will shed light on a) circulation in the Equatorial Pacific during and around the Carbonate Crash and Messinian Salinity crisis, and b)  the timing and amplitude of glacio-eustasy during the Messinian Salinity crisis, and whether or not there is a link between restriction of the Mediterranean basin and global sea-level.