The Solomon Sea occupies a small marginal oceanic basin previously uninvestigated by the Deep Sea Drilling Project/Ocean Drilling Program (DSDP/ODP). Holes 1115B and 1115C were drilled in the southwestern part of the Solomon Sea (Fig. F1) during ODP Leg 180 (June-August 1998). Drilling in these holes penetrated a thick Pliocene section, providing an opportunity for paleoclimatic investigation in a previously unstudied part of the world ocean.
The Pliocene Epoch was a time of global climatic deterioration. The planet was changing from the "Greenhouse Earth" of the early Tertiary to the "Icehouse Earth" of the late Neogene and Quaternary. Climatic change has a direct effect on the temperature of oceanic surface waters. Various proxies have been used to assess the changing temperatures of oceanic waters, and thus climate, with time (e.g., oxygen-isotope ratios, alkenone measurements, temperature-sensitive single species or assemblages of various microfossils, structural changes in microfossil skeletons, etc.). In this study, I have used a technique employing two temperature-diagnostic nannofossil species in an attempt to identify trends in surface water changes in the Solomon Sea during the Pliocene.