Vast Neogene laminated diatom mat deposits from the eastern equatorial Pacific Ocean

Kemp, Alan E. S.; Baldauf, J.G.

doi:10.1038/362141a0

Cited by 151 publications

(98 citation statements)

References 21 publications

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“…These large jumps in mean density value adversely affect the results of bandpass filtering of the data. Their origin is partly the episodes during which laminated sediments accumulated (Kemp and Baldauf, 1993). It is difficult to put bounds on possible sedimentation rate excursions associated with these events and, in some details, the tuning is speculative in those parts of the record associated with accumulation of laminated sediments.…”

Section: Resultsmentioning

confidence: 99%

A New Late Neogene Time Scale: Application to Leg 138 Sites

Shackleton¹,

Crowhurst²,

Hagelberg³

et al. 1995

Proceedings of the Ocean Drilling Program, 138 Scientific Results

225

240

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The sediments recovered during Leg 138 provide a remarkable opportunity to improve the geological time scale of the late Neogene. We have developed new time scales in the following steps. First, we constructed age models on the basis of shipboard magnetostratigraphy and biostratigraphy, using the time scale of Berggren, Kent, and Flynn (1985). Second, we refined these age models using shipboard GRAPE density measurements to provide more accurate correlation points. Third, we calibrated a time scale for the past 6 m.y. by matching the high-frequency GRAPE density variations to the orbital insolation record of Berger and Loutre (1991); we also took into account δ 18 θ records, where they were available. Fourth, we generated a new seafloor anomaly time scale using our astronomical calibration of C3A.n (t) at 5.875 Ma and an age of 9.639 Ma for C5n.ln (t) that is based on a new radiometric calibration (Baksi, 1992). Fifth, we recalibrated the records older than 6 Ma to this new scale. Finally, we reconsidered the 6-to 10-Ma interval and found that this could also be partially tuned astronomically.

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Section: Resultsmentioning

confidence: 99%

A New Late Neogene Time Scale: Application to Leg 138 Sites

Shackleton¹,

Crowhurst²,

Hagelberg³

et al. 1995

Proceedings of the Ocean Drilling Program, 138 Scientific Results

225

240

View full text Add to dashboard Cite

show abstract

“…This shallower CCD, at a paleodepth of approximately 4.5 km, along with associated reduced carbonate Fluorescence (XRF) to collect high-resolution profiles of chemical data for much of the time interval. Furthermore, quantitative studies of microfossil assemblages will give new insights into the changes in the equatorial Pacific ecosystem, including the development of a diatom-based ecology in the late middle Miocene, with significant monospecific diatom intervals during the transition (Kemp and Baldauf, 1993). Finally, downhole logging will enable refinement of the equatorial seismic stratigraphy developed by Mayer et al (1985) from Deep Sea Drilling Project Leg 85.…”

Section: Initial Results and Future Directionsmentioning

confidence: 99%

The Pacific Equatorial Age Transect, IODP Expeditions 320 and 321: Building a 50-Million-Year-Long Environmental Record of the Equatorial Pacific Ocean

Lyle

Pälike

Nishi

et al. 2010

Scientific Drilling

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In March 2009, the R/V JOIDES Resolution returned to operations after its extended refit and began with a drilling program ideally suited to its drilling strengths, the Pacific Equatorial Age Transect (PEAT, IODP Exp 320/321; Fig. 1A). The PEAT drilling program was developed to understand how a major oceanic region evolved over the Cenozoic Era(65–0 Ma) and how it interacted with global climate. It specifically targeted the interval between 52 Ma and 0 Ma and drilled a series of sites that originated on the paleoequator. These sites have since been moved to the northwest by plate tectonics.The equatorial Pacific is an important target for paleocean ographic study because it is a significant ‘cog’ in the Earth’s climate machine, representing roughly half of the total tropical oceans that in turn represent roughly half of the total global ocean area. Prior drilling in both the Deep Sea Drilling Project (DSDP) and the Ocean Drilling Program (ODP) outlined the changes that have occurred through the Cenozoic (e.g., van Andel et al., 1975; Pisias et al., 1995). Not only did the earlier work fail to cover sufficient timeintervals but also many of the sites were cored with ‘first-generation’ scientific drilling technology with incomplete and disturbed sediment recovery and thus cannot be used for detailed studies

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“…In our study, the extinction of C. cahobasensis may reflect the major constriction of the Central American seaway between 4.7 and 4.2 Ma. This time frame is based on the increasing surface-water salinity in the Caribbean (Keigwin, 1982;Haug et al, 2001), an increasing temperature gradient in the Pacific (Chaisson and Ravelo, 2000), increases in carbonate sand deposits and ␦ 13 C values of epibenthic foraminifera in the Caribbean (Haug and Tiedemann, 1998), and cessation of vast diatom-mat assemblages in the eastern equatorial Pacific (Kemp and Baldauf, 1993). Although these deep-marine records were derived from open-ocean settings, a corresponding change in shallow-marine benthic foraminifera and corals indicates that changes in ocean circulation also affected nearshore environments during this interval (Collins et al, 1996).…”

Section: Discussionmentioning

confidence: 99%