2015 GSA Annual Meeting in Baltimore, Maryland, USA (1-4 November 2015)

Paper No. 41-18
Presentation Time: 9:00 AM-5:30 PM


HULL, Katherine, Department of Geology, Texas A&M University, College Station, TX 77845, ALVAREZ ZARIKIAN, Carlos A., International Ocean Discovery Program, Texas A&M University, 1000 Discovery Dr, College Station, TX 77845, BASSETTI, Maria Angela, CEFREM, University of Perpignan, Perpignan, 66860, France and HOLBOURN, Ann, Institut für Geowissenschaften, Christian-Albrechts-Universität, Olshausenstrasse 40, Kiel, 24118, Germany, kah3575@tamu.edu

The objective of this study was to examine the variability of ostracod assemblages at IODP Site U1429 and their relationship to changes in the intensity of the Tsushima Warm Current (TWC) and intermediate bottom water ventilation in the East China Sea during Marine Isotope Stages 3 to 1 (or the last ~30 ky). Site U1429 is located at 31°37.04′N, 128°59.85′E and 732 mbsl in the East China Sea (ECS). The ECS is influenced by continental freshwater runoff derived from the Yangtze River and also by the TWC, a branch of the Kuroshio Current that enters the Sea of Japan through the narrow Tsushima Strait. Previous works had shown that ostracod species of Bradleya, Krithe, Cytheropteron, and Legitimocythere are characteristic taxa of an assemblage associated with the Tsushima Warm Current off the Korean peninsula. Consistent with previous results, this study shows that Krithe spp., Bradleya albatrossia, Cytheropteron cf. C. uchioi, Legitimocythere sp. and Falsobuntonia taiwanica are associated with intensification of the TWC in the ECS and warmer global climate during MIS 1 and 3. Warmer surface waters associated with a strong TWC are also inferred by an increase in the abundance of the planktonic foraminifera Globorotalia menardii. In contrast, Marine Isotope Stage 2 is characterized by a ‘glacial’ ostracod assemblage conformed by the genera Polycope, Amphileberis, ‘Acanthocythereis’, Argilloecia and Paijenborchella. Our results show that the distribution of ostracod assemblages in the ECS is a reliable indicator of past, and possibly future, changes in the Tsushima Warm Current.