Proceedings of the Ocean Drilling Program, 207 Initial Reports

Erbacher, Jochen; Mosher, D C; Malone, M.J.

doi:10.2973/odp.proc.ir.207.2004

Cited by 343 publications

(47 citation statements)

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“…We suspect that these negative values in the clay layer are a result of early diagenesis under sulfate reduction and do not reflect the primary signal. Sulfate reduction occurs at this site today [Erbacher et al, 2004] and given the location and sedimentation rates, might have altered the primary signal. Nunes and Norris [2006] also suggested diagenetic overprinting of the d 13 C values of benthic foraminifera from across the PETM at Demerara Rise because of the unusually low values and observations of calcite overgrowths on benthic foraminifer tests.…”

Section: Paleoredox Changesmentioning

confidence: 97%

Deep-sea redox across the Paleocene-Eocene thermal maximum

Pälike

Delaney

Zachos

2014

Geochem. Geophys. Geosyst.

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Large amounts of 13 C-depleted carbon were released to the oceans and atmosphere during a period of abrupt global warming at the Paleocene-Eocene thermal maximum (PETM) (55 Ma). Investigations of qualitative sedimentologic and paleontologic redox proxies such as bioturbation and benthic assemblages from pelagic and hemipelagic sections suggest transient reductions in bottom water oxygen during this interval, possibly on a global scale. Here, we present bulk sediment manganese (Mn) and uranium (U) enrichment factors (EF) in Atlantic and Pacific deep-sea cores to constrain relative paleoredox changes across the PETM. Mn EF range from 1 to 9 in Atlantic sites, 1 to 35 in Southern Ocean sites, and are at crustal averages (EF 5 1) in Pacific sites. U EF range from 1 to 5 in Atlantic sites, 1 to 90 in Southern Ocean sites, and are at crustal averages in Pacific sites. Our results indicate suboxic conditions prior to, during, and in the recovery from the PETM at intermediate depth sites in the Atlantic and Southern Ocean while the Pacific sites remained relatively oxygenated. The difference in oxygenation between the Atlantic and Pacific sites leads us to suggest the source for isotopically light carbon release during the PETM was in the Atlantic.

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Section: Paleoredox Changesmentioning

confidence: 97%

Deep-sea redox across the Paleocene-Eocene thermal maximum

Pälike

Delaney

Zachos

2014

Geochem. Geophys. Geosyst.

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“…Core recovery and stratigraphic control are generally poor in the lowest 100 m of the hole (Cores 62R-71R) and it was not possible to closely constrain the level of the Early Eocene hypothermals, which have been recognized as globally significant events through the results of recent scientific drilling on Shatsky Rise, ODP Leg 198 (Bralower et al 2002); Demerara Rise, ODP Leg 207 (Erbacher et al 2004) and on Walvis Ridge, ODP Leg 208 (Zachos et al 2004). If the lowest sedimentary magnetic normal corresponds to C24n, as interpreted here, then Cores 70R and 71R might contain a record of the Eocene Thermal Maximum '3' (ETM3), as calibrated by Galeotti et al (2010).…”

Section: Implications For Palaeoceanographymentioning

confidence: 99%

Integrated biomagnetochronology for the Palaeogene of ODP Hole 647A: implications for correlating palaeoceanographic events from high to low latitudes

Firth

Eldrett

Harding

et al. 2012

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Lower Eocene to Oligocene microfossil-rich hemipelagic sediments in ODP Hole 647A, southern Labrador Sea, provide a strategic section for resolving the early history of high North Atlantic climates and ocean circulation, and for correlating with carbonate-poor lower Cenozoic sediments in the Arctic and Nordic seas. Our new, integrated palaeomagneto-and multigroup biostratigraphy (63 dinoflagellate cyst, calcareous nannofossil, planktonic foraminifer and diatom datums) significantly improves Site 647 chronostratigraphy and provides a framework for future studies. This new age model, coupled with provisional d 18 O analyses, provides greater confidence in the location of significant ocean-climate events at this site, including the Eocene-Oligocene transition and the Middle Eocene Climatic Optimum. Early Eocene hyperthermals may also be present near the base of the section. Palaeomagnetic age control is significantly improved in the Eocene, but not in the Oligocene. Revised estimates of sedimentation and biogenic flux indicate changes in supply and preservation that may be climatically controlled. A Lower to Middle Eocene hiatus is more precisely constrained, with a c. 4 million year duration. Age and depth errors quantify the age uncertainties throughout the section. Our revised age model will play an important role in stratigraphic correlation between very high latitude and lower latitude sites. Supplementary material: All tables with ages and age-derived calculations based on the Gradstein et al. (2004) timescale used herein are reproduced as supplementary tables using both the Gradstein et al. (2004) and the Cande & Kent (1995) timescales (Tables DS1-DS6). Discrete sample and shipboard pass-through cryomagnetometer palaeomagnetic data, planktonic foraminifer and fine fraction (,20 mm) stable isotope data, raw and processed core GRA density data, and specifications and results of GRA density spectral analyses are also provided as supplementary tables (Tables DS7-DS11). These tables are available at www.geolsoc.org.uk/SUP18546. Downloaded from J. V. FIRTH ET AL. J. V. FIRTH ET AL. J. V. FIRTH ET AL. } HO Nannotetrina spp.; LO of D. hesslandii (equivalent to R. bisecta). 1 HO Nannotetrina fulgens. 2 LO R. bisecta between top and base of C18r.

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“…We have used industry MCS and borehole data from ODP sites 1257 to 1261 (Gouyet et al 1993;Silva et al 1999;Erbacher et al 2004) to provide the stratigraphic reference for the sediment column imaged within the region and, in particular, along Profile A (Fig. 5).…”

Section: Regional Stratigraphymentioning

confidence: 99%

“…Further north at the French Guiana margin, existing seismic data are limited to industry MCS and well data (Gouyet et al 1993) and site survey and borehole data from Ocean Drilling Program (ODP) sites 1257 to 1261 (Erbacher et al 2004), acquired between 8.5 • N and 9.5 • N, 53.5 • W and 55 • W on the Demerara Plateau (Fig. 2).…”

Section: Introductionmentioning

confidence: 99%

Crustal structure of the French Guiana margin, West Equatorial Atlantic

Greenroyd¹,

Peirce²,

Rodger

et al. 2007

Geophysical Journal International

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S U M M A R YGeophysical data from the Amazon Cone Experiment are used to determine the structure and evolution of the French Guiana and Northeast Brazil continental margin, and to better understand the origin and development of along-margin segmentation. A 427-km-long combined multichannel reflection and wide-angle refraction seismic profile acquired across the southern French Guiana margin is interpreted, where plate reconstructions suggest a rift-type setting.The resulting model shows a crustal structure in which 35-37-km-thick pre-rift continental crust is thinned by a factor of 6.4 over a distance of ∼70 km associated with continental breakup and the initiation and establishment of seafloor spreading. The ocean-continent boundary is a transition zone up to 45 km in width, in which the two-layered oceanic-type crustal structure develops. Although relatively thin at 3.5-5.0 km, such thin oceanic crust appears characteristic of the margin as a whole.There is no evidence of rift-related magmatism, either as seaward-dipping sequences in the reflection data or as a high velocity region in the lower crust in the P-wave velocity model, and as a such the margin is identified as non-volcanic in type. However, there is also no evidence of the rotated fault block and graben structures characteristic of rifted margins. Consequently, the thin oceanic crust, the rapidity of continental crustal thinning and the absence of characteristic riftrelated structures leads to the conclusion that the southern French Guiana margin has instead developed in an oblique rift setting, in which transform motion also played a significant role in the evolution of the resulting crustal structure and along-margin segmentation in structural style.

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Proceedings of the Ocean Drilling Program, 207 Initial Reports

Cited by 343 publications

References 0 publications

Deep-sea redox across the Paleocene-Eocene thermal maximum

Deep-sea redox across the Paleocene-Eocene thermal maximum

Integrated biomagnetochronology for the Palaeogene of ODP Hole 647A: implications for correlating palaeoceanographic events from high to low latitudes

Crustal structure of the French Guiana margin, West Equatorial Atlantic

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