The onset of the Paleocene-Eocene Thermal Maximum (PETM) at Sites 1209 and 1210 (Shatsky Rise, Pacific Ocean) as recorded by planktonic Foraminifera

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doi: 10.1016/j.marmicro.2006.11.007
Author(s): Petrizzo, Maria Rose
Author Affiliation(s): Primary:
University of Milan, Dipartimento di Scienze della Terra Ardito Desio, Milan, Italy
Volume Title: Marine Micropaleontology
Source: Marine Micropaleontology, 63(3-4), p.187-200. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0377-8398 CODEN: MAMIDH
Note: In English. Supplemental information/data is available in the online version of this article. 67 refs.; illus., incl. sketch map
Summary: High-resolution biostratigraphic and quantitative studies of subtropical Pacific planktonic foraminiferal assemblages (Ocean Drilling Program, Leg 198 Shatsky Rise, Sites 1209 and 1210) are performed to analyse the faunal changes associated with the Paleocene-Eocene Thermal Maximum (PETM) at about 55.5 Ma. At Shatsky Rise, the onset of the PETM is marked by the abrupt onset of a negative carbon isotope excursion close to the contact between carbonate-rich ooze and overlying clay-rich ooze and corresponds to a level of poor foraminiferal preservation as a result of carbonate dissolution. Lithology, planktonic foraminiferal distribution and abundances, calcareous plankton and benthic events, and the negative carbon isotope excursion allow precise correlation of the two Shatsky Rise records. Results from quantitative analyses show that Morozovella dominates the assemblages and that its maximum relative abundance is coincident with the lowest δ13C values, whereas subbotinids are absent in the interval of maximum abundance of Morozovella. The excursion taxa (Acarinina africana, Acarinina sibaiyaensis, and Morozovella allisonensis) first appear at the base of the event. Comparison between the absolute abundances of whole specimens and fragments of genera demonstrate that the increase in absolute abundance of Morozovella and the decrease of Subbotina are not an artifact of selective dissolution. Moreover, the shell fragmentation data reveal Subbotina to be the more dissolution-susceptible taxon. The upward decrease in abundance of Morozovella species and the concomitant increase in test size of Morozovella velascoensis are not controlled by dissolution. These changes could be attributed to the species' response to low nutrient supply in the surface waters and to concomitant changes in the physical and chemical properties of the seawater, including increased surface stratification and salinity. Comparison of the planktonic foraminiferal changes at Shatsky Rise to those from other PETM records (Sites 865 and 690) highlights significant similarities, such as the decline of Subbotina at the onset of the event, and discrepancies, including the difference in abundance of the excursion taxa. The observed planktonic foraminifera species response suggests a warm-oligotrophic scenario with a high degree of complexity in the ocean structure. Abstract Copyright (2007) Elsevier, B.V.
Year of Publication: 2007
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Biostratigraphy; C-13/C-12; Carbon; Cenozoic; Climate change; Eocene; Foraminifera; Invertebrata; Isotope ratios; Isotopes; Leg 113; Leg 143; Leg 198; Lower Eocene; Maud Rise; Microfossils; Mid-Pacific Mountains; North Pacific; Northwest Pacific; ODP Site 1209; ODP Site 1210; ODP Site 690; ODP Site 865; Ocean Drilling Program; Pacific Ocean; Paleocene; Paleocene-Eocene Thermal Maximum; Paleoclimatology; Paleogene; Planktonic taxa; Protista; Shatsky Rise; Southern Ocean; Stable isotopes; Stratigraphic boundary; Tertiary; Upper Paleocene; Weddell Sea; West Pacific
Coordinates: N323900 N324000 E1583100 E1583000
N321300 N321300 E1581600 E1581600
S650938 S650937 E0011218 E0011218
N182624 N182626 W1793320 W1793321
Record ID: 2007116729
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands