Distinguishing the influence of diagenesis on the paleoecological reconstruction of nannoplankton across the Paleocene/Eocene Thermal Maximum; an example from the Kerguelen Plateau, southern Indian Ocean

Online Access: Get full text
doi: 10.1016/j.marmicro.2009.03.003
Author(s): Jiang, Shijun; Wise, Sherwood W., Jr.
Author Affiliation(s): Primary:
Pennsylvania State University, Department of Geosciences, University Park, PA, United States
Florida State University, United States
Volume Title: Marine Micropaleontology
Source: Marine Micropaleontology, 72(1-2), p.49-59. Publisher: Elsevier, Amsterdam, Netherlands. ISSN: 0377-8398 CODEN: MAMIDH
Note: In English. Based on Publisher-supplied data; includes appendix; illus., incl. 2 tables
Summary: The Paleocene/Eocene Thermal Maximum (PETM, ca. 55 Ma) is an abrupt, profound perturbation of climate and the carbon cycle associated with a massive injection of isotopically light carbon into the ocean-atmosphere system. As such, it provides an analogue for understanding the interplay between phytoplankton and climate under modern anthropogenic global-warming conditions. However, the accompanying enhanced dissolution poses uncertainty on the reconstruction of the affected ecology and productivity. We present a high-resolution record of bulk isotopes and nannofossil absolute abundance from Ocean Drilling Program (ODP) Site 1135 on the Kerguelen Plateau, Southern Indian Ocean to quantitatively constrain for the first time the influence of dissolution on paleoecological reconstruction. Our bulk-carbonate isotope record closely resembles that of the classic PETM site at ODP Site 690 on the opposite side of the Antarctic continent, and its correlation with those from ODP Sites 690, 1262 and 1263 records allows recognition of 14 precessional cycles upsection from the onset of the carbon isotopic excursion (CIE). This, together with a full range of common Discoasteraraneus and an abundance crossover between Fasciculithus and Zygrhablithusbijugatus, indicates the presence of the PETM at Site 1135, a poorly known record with calcareous fossils throughout the interval. The strong correlation between the absolute abundances of Chiasmolithus and coccolith assemblages reveals a dominant paleoecological signal in the poorly preserved fossil assemblages, while the influence of dissolution is only strong during the CIE. This suggests that r-selected taxa can preserve faithful ecological information even in the severely-altered assemblages studied here, and therefore provide a strong case for the application of nannofossils to paleoecological studies in better-preserved PETM sections. The inferred nannoplankton productivity drops abruptly at the CIE onset, but rapidly increases after the CIE peak, both of which may be driven by nutrient availability related to ocean stratification and vertical mixing due to changed sea-surface temperatures. Abstract Copyright (2009) Elsevier, B.V.
Year of Publication: 2009
Research Program: ODP Ocean Drilling Program
Key Words: 02 Geochemistry; 12 Stratigraphy, Historical Geology and Paleoecology; Algae; Assemblages; Atlantic Ocean; C-13/C-12; Carbon; Cenozoic; Chemostratigraphy; Correlation; Diagenesis; Indian Ocean; Isotope ratios; Isotopes; Kerguelen Plateau; Leg 113; Leg 183; Leg 208; Maud Rise; Microfossils; Nannofossils; ODP Site 1135; ODP Site 1262; ODP Site 1263; ODP Site 690; Ocean Drilling Program; Paleocene-Eocene Thermal Maximum; Paleoclimatology; Paleoecology; Paleogene; Plantae; Solution; South Atlantic; Southern Ocean; Stable isotopes; Tertiary; Walvis Ridge; Weddell Sea
Coordinates: S594200 S594200 E0841624 E0841624
S650938 S650937 E0011218 E0011218
S283200 S271100 E0024700 E0013400
Record ID: 2010045080
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute. Reference includes data from CAPCAS, Elsevier Scientific Publishers, Amsterdam, Netherlands