Multiple early Eocene hyperthermals; their sedimentary expression on the New Zealand continental margin and in the deep sea

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doi: 10.1130/G23648A.1
Author(s): Nicolo, Micah J.; Dickens, Gerald R.; Hollis, Christopher J.; Zachos, James C.
Author Affiliation(s): Primary:
Rice University, Department of Earth Sciences, Houston, TX, United States
Institute of Geological and Nuclear Sciences, New Zealand
University of California-Santa Cruz, United States
Volume Title: Geology (Boulder)
Source: Geology (Boulder), 35(8), p.699-702. Publisher: Geological Society of America (GSA), Boulder, CO, United States. ISSN: 0091-7613 CODEN: GLGYBA
Note: In English. With GSA Data Repository Item 2007180. 22 refs.; sects., sketch map
Summary: The Paleocene-Eocene thermal maximum (PETM) ca. 55.5 Ma was a geologically brief interval characterized by massive influx of isotopically light carbon, extreme changes in global climate, and profound variations in Earth system processes. An outstanding issue is whether it was an isolated event, or the most prominent example of a recurring phenomenon. Recent studies of condensed deep-sea sections support the latter, but this finding remains uncertain. Here we present and discuss lithologic and carbon isotope records across two lower Eocene outcrops on South Island, New Zealand. The PETM manifests as a marl-rich horizon with a significant negative carbon isotope excursion (CIE). Above, in sediment deposited between 54 and 53 Ma, are four horizons with similar though less pronounced expressions. Marl beds of all five horizons represent increased terrigenous sedimentation, presumably linked to an accelerated hydrological cycle. Five corresponding clay-rich horizons and CIEs are found in deep-sea records, although the lithologic variations represent carbonate dissolution rather than siliciclastic dilution. The presence of five intervals with similar systemic responses in different environments suggests a mechanism that repeatedly injected large masses of 13C-depleted carbon during the early Eocene.
Year of Publication: 2007
Research Program: ODP Ocean Drilling Program
Key Words: 12 Stratigraphy, Historical Geology and Paleoecology; Atlantic Ocean; Australasia; Blake Nose; Blake Plateau; C-13/C-12; Calcium carbonate; Carbon; Carbonate rocks; Cenozoic; Clarence Valley; Clastic rocks; Climate change; Continental margin sedimentation; Correlation; Dee Stream; Deep-sea environment; Depositional environment; Eocene; Geochemistry; Hyperthermal events; Isotope ratios; Isotopes; Leg 171B; Leg 208; Limestone; Lower Eocene; Marine environment; Marl; Mead Stream; New Zealand; North Atlantic; ODP Site 1051; ODP Site 1262; Ocean Drilling Program; Outcrops; PETM; Paleo-oceanography; Paleocene; Paleocene-Eocene Thermal Maximum; Paleoclimatology; Paleogene; Paleotemperature; Sedimentary rocks; Sedimentation; Shallow-water environment; South Atlantic; South Island; Stable isotopes; Tertiary; Upper Paleocene; Walvis Ridge
Coordinates: S422000 S420000 E1741000 E1734500
S271100 S271100 E0013500 E0013400
N300311 N300311 W0762128 W0762128
Record ID: 2007084827
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