Cenozoic bathyal and abyssal ostracods beneath the oligotrophic South Pacific Gyre (IODP Expedition 329 Sites U1367, U1368 and U1370)

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doi: 10.1016/j.palaeo.2014.07.024
Author(s): Alvarez Zarikian, Carlos Andres
Author Affiliation(s): Primary:
Texas A&M University, International Ocean Discovery Program, College Station, TX, United States
Other:
Trieste University, Italy
Texas A&M University, United States
Volume Title: Ostracoda as proxies for palaeoenvironmental changes; selected papers from 17th ISO
Volume Author(s): Gliozzi, Elsa, editor; Pugliese, Nevio; Alvarez Zarikian, Carlos Andres
Source: Palaeogeography, Palaeoclimatology, Palaeoecology, Vol.419, p.115-142; 17th international symposium on Ostracoda, Rome, Italy, July 22-26, 2013, edited by Elsa Gliozzi, Nevio Pugliese and Carlos Andres Alvarez Zarikian. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0031-0182 CODEN: PPPYAB
Note: In English. 114 refs.; illus., incl. 11 plates, 2 tables, sketch map
Summary: This study reports on Paleocene through Pleistocene deep sea ostracod assemblages from carbonate sequences recovered at Integrated Ocean Drilling Program (IODP) Sites U1367, U1368, and U1370 during Expedition 329 to the South Pacific Gyre (SPG). The SPG has the lowest surface primary productivity in the world oceans, and the sedimentary system beneath it has the lowest rates of organic matter flux to the seafloor in the ocean. Results show that this oligotrophic oceanic environment supported abundant and diverse ostracod faunas during the Oligocene, and the middle Miocene suggesting that ostracods are capable of exploiting low levels of food availability in the deep ocean. The SPG records revealed ostracod assemblages following major global climatic transitions: the Cretaceous/Paleocene (∼ 65.5 Ma) and the Eocene/Oligocene (∼ 33.5 Ma) transitions, and the middle Miocene climatic optimum (∼ 14 Ma). The Danian ostracod assemblage is scarce and characterized by Paraphysocythere spp. and Anebocythereis hostizea. High faunal turnover by the early Oligocene gives rise to an assemblage predominantly characterized by typical lower bathyal and abyssal genera Krithe, Poseidonamicus, Argilloecia, and Cytheropteron that are indicative of cold, moderately oxygenated conditions and signal the cooling of the deep ocean after the E/O transition. An increase in abundance of robust epifaunal taxa Bradleya, Henryhowella, Dutoitella, Pennyella, and Rugocythereis, and a pronounced decrease Argilloecia and Cytheropteron characterize the middle Miocene and Pleistocene assemblages, and indicate the presence of more corrosive bottom waters and enhanced oligotrophic conditions in the SPG. However, low variability in the ostracod assemblage taxonomic composition and stratigraphic distribution at Sites U1367 and U1368 suggest that mostly stable paleoceanographic conditions existed in the South Pacific Gyre during the early to the late Oligocene and from the middle to late Miocene (U1368). Declines in ostracod abundances toward the top of the sedimentary sequences at these sites are synchronous with the late Oligocene warming and the late Miocene carbonate crash in the equatorial Pacific, but they seem to also overlap the time when the site locations subsided below the calcium carbonate compensation depth (CCD) as they moved away from the East Pacific Rise. Abstract Copyright (2015) Elsevier, B.V.
Year of Publication: 2015
Research Program: DSDP Deep Sea Drilling Project
IODP Integrated Ocean Drilling Program
IPOD International Phase of Ocean Drilling
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Arthropoda; Assemblages; Biostratigraphy; Carbonate compensation depth; Cenozoic; Cores; Crustacea; Deep Sea Drilling Project; Deep-sea environment; East Pacific; Eocene; Equatorial Pacific; Expedition 329; Foraminifera; IODP Site U1367; IODP Site U1368; IODP Site U1370; IPOD; Integrated Ocean Drilling Program; Invertebrata; Leg 92; Mandibulata; Marine environment; Marine sediments; Microfossils; Miocene; Neogene; Oligocene; Ostracoda; Pacific Ocean; Paleo-oceanography; Paleocene; Paleoclimatology; Paleogene; Paleogeography; Pleistocene; Pliocene; Protista; Quaternary; Range; Sediments; South Pacific; South Pacific Gyre; Southeast Pacific; Tertiary
Coordinates: S275500 S275500 W1230939 W1230939
S262853 S262853 W1375622 W1375622
S415107 S415107 W1530623 W1530623
Record ID: 2015039427
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands