Expedition 383 summary

• Main Authors: Winckler, G., Lamy, F., Alvarez Zarikian, C. A., Arz, H. W., Basak, C., Brombacher, A., Esper, O. M., Farmer, J. R., Gottschalk, J., Herbert, L. C., Iwasaki, S., Lawson, V. J., Lembke-Jene, L., Lo, L., Malinverno, E., Michel, E., Middleton, J. L., Moretti, S., Moy, C. M., Ravelo, A. C., Riesselman, C. R., Saavedra-Pellitero, M., Seo, I., Singh, R. K., Smith, R. A., Souza, A. L., Stoner, J. S., Venancio, I. M., Wan, S., Zhao, X., Foucher McColl, N.
• Other Authors: Lamy, F., Winckler, G., Alvarez Zarikian, C.A., and the Expedition 383 Scientists, Winckler, G, Lamy, F, Alvarez Zarikian, C, Arz, H, Basak, C, Brombacher, A, Esper, O, Farmer, J, Gottschalk, J, Herbert, L, Iwasaki, S, Lawson, V, Lembke-Jene, L, Lo, L, Malinverno, E, Michel, E, Middleton, J, Moretti, S, Moy, C, Ravelo, A, Riesselman, C, Saavedra-Pellitero, M, Seo, I, Singh, R, Smith, R, Souza, A, Stoner, J, Venancio, I, Wan, S, Zhao, X, Foucher McColl, N
• Format: Book Part
• Language: English
• Published: College Station, TX (International Ocean Discovery Program) 2021
• Subjects: International Ocean Discovery Program; IODP; JOIDES Resolution; Expedition 383; Dynamics of the Pacific Antarctic Circumpolar Current; Site U1539; Site U1540; Site U1541; Site U1542; Site U1543; Site U1544; Southern Ocean; South Pacific; Chilean margin; paleoceanography; Antarctic Circumpolar Current; oceanic fronts; Circumpolar Deep Water; Antarctic Intermediate Water; marine carbon cycle; dust; biological productivity; iron fertilization; southern westerly winds; Patagonian ice sheet; West Antarctic ice sheet; GEO/01 - PALEONTOLOGIA E PALEOECOLOGIA; GEO/02 - GEOLOGIA STRATIGRAFICA E SEDIMENTOLOGICA; Antarctic; The Antarctic; Drake Passage; West Antarctic Ice Sheet; Pacific; Indian; New Zealand; Antarc*; Ice Sheet
• Online Access: http://hdl.handle.net/10281/358641; https://doi.org/10.14379/iodp.proc.383.101.2021

The Antarctic Circumpolar Current (ACC), the world’s strongest zonal current system, connects all three major ocean basins of the global ocean and therefore integrates and responds to global climate variability. Its flow is largely driven by strong westerly winds and is constricted to its narrowest extent in the Drake Passage. Fresh and cold Pacific surface and intermediate water flowing through the Drake Passage (cold-water route) and warm Indian Ocean water masses flowing through the Agulhas region (warm-water route) are critical for the South Atlantic contribution to Meridional Overturning Circulation changes. Furthermore, physical and biological processes associated with the ACC affect the strength of the ocean carbon pump and therefore are critical to feedbacks linking atmospheric CO2 concentrations, ocean circulation, and climate/cryosphere on a global scale. In contrast to the Atlantic and Indian sectors of the ACC, and with the exception of drill cores from the Antarctic continental margin and off New Zealand, there are no deep-sea drilling paleoceanographic records from the Pacific sector of the ACC. To advance our understanding of Miocene to Holocene atmosphere-ocean-cryosphere dynamics in the Pacific and their implications for regional and global climate and atmospheric CO2, International Ocean Discovery Program Expedition 383 recovered sedimentary sequences at (1) three sites in the central South Pacific (CSP) (U1539, U1540, and U1541), (2) two sites at the Chilean margin (U1542 and U1544), and (3) one site from the pelagic eastern South Pacific (U1543) close to the entrance to the Drake Passage. Because of persistently stormy conditions and the resulting bad weather avoidance, we were not successful in recovering the originally planned Proposed Site CSP-3A in the Polar Frontal Zone of the CSP. The drilled sediments at Sites U1541 and U1543 reach back to the late Miocene, and those at Site U1540 reach back to the early Pliocene. High sedimentation rate sequences reaching back to the early Pleistocene ...