Terminal Cretaceous Environmental Events

Officer, Charles B.; Drake, Charles L.

doi:10.1126/science.227.4691.1161

Cited by 231 publications

(58 citation statements)

References 75 publications

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“…Therefore, PGE-enrichment processes from hydrothermal activity (Halbach et al 1989b;Koide et al 1991;Officer and Drake 1985) may not have contributed to the PGE and Au concentrations of ANS Fe-Mn crusts. Substrate rocks neither (Crocket 1972) 4 73 na Karoo basalt (Naldrett 1981) 88 147 80 Duluth basalt (Naldrett 1981) 6 15 16 Deccan basalt (Crocket and Paul 2004) 0.024 na na Carbonate ooze (Hodge et al 1985) na na na Siliceous ooze (Hodge et al 1985) na na na Ultramafic rocks (Crocket 1981) 3.8 6.1 3 Black shale-Chine (Coveney et al 1992) 0.1 16 na Continental crust (Govett 1983 provide fluids that contribute to the formation of Fe-Mn crusts nor diagenetically influence their composition (Banakar and Hein 2000;Hein and Morgan 1999).…”

Section: Resultsmentioning

confidence: 99%

Platinum group elements and gold in ferromanganese crusts from Afanasiy-Nikitin seamount, equatorial Indian Ocean: Sources and fractionation

et al. 2007

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The major element relationships in ferromanganese (Fe-Mn) crusts from Afanasiy-Nikitin seamount (ANS), eastern equatorial Indian Ocean, appear to be atypical. High positive correlations (r = 0.99) between Mn/Co and Fe/Co ratios, and lack of correlation of those ratios with Co, Ce, and Ce/Co, indicate that the ANS Fe-Mn crusts are distinct from Pacific seamount Fe-Mn crusts, and reflect region-specific chemical characteristics. The platinum group elements (PGE: Ir, Ru, Rh, Pt, and Pd) and Au in ANS Fe-Mn crusts are derived from seawater and are mainly of terrestrial origin, with a minor cosmogenic component. The Ru/Rh (0.5-2) and Pt/Ru ratios (7-28) are closely comparable to ratios in continental basalts, whereas Pd/Ir ratios exhibit values (< 2) similar to CI-chondrite (∼ 1). The chondrite-normalized PGE patterns are similar to those of igneous rocks, except that Pd is relatively depleted. The water depth of Fe-Mn crust formation appears to have a first-order control on both major element and PGE enrichments. These relationships are defined statistically by significant (r > 0.75) correlations between water depth and Mn/Co, Fe/Co, Ce/Co, Co, and the PGEs. Fractionation of the PGE-Au from seawater during colloidal precipitation of the major-oxide phases is indicated by well-defined linear positive correlations (r > 0.8) of Co and Ce with Ir, Ru, Rh, and Pt; Au/Co with Mn/Co; and by weak or no correlations of Pd with water depth, Co-normalized major-element ratios, and with the other PGE (r < 0.5). The strong enrichment of Pt (up to 1 ppm) relative to the other PGE and its positive correlations with Ce and Co demonstrate a common link for the high concentrations of all three elements, which likely involves an oxidation reaction on the Mn-oxide and Fe-oxyhydroxide surfaces. The documented fractionation of PGE-Au and their positive association with redox sensitive Co and Ce may have applications in reconstructing past-ocean redox conditions and water masses.

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Section: Resultsmentioning

confidence: 99%

Platinum group elements and gold in ferromanganese crusts from Afanasiy-Nikitin seamount, equatorial Indian Ocean: Sources and fractionation

et al. 2007

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“…The hypothesis that an extraterrestrial body struck the earth's surface about 65 Ma before the present (A1varez et al, 1980Bohor et al, 1984) is now widely accepted, although the data could be explained by intense volcanism (Officer and Drake, 1985). Whatever its cause, the terminal Cretaceous event had a major effect on the vegetation of a large part of North America.…”

Section: Rearrangements In Community Structure (Stages 2 and 4)mentioning

confidence: 99%

The reciprocal interaction of angiosperm evolution and tetrapod herbivory

Wing

Tiffney

1987

Review of Palaeobotany and Palynology

145

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“…Also, recent estimates of the duration and magnitude of fluxes of e.g. iridium to the seafloor is based on these numbers [20,21]. To improve the accuracy of these calculations it is necessary to have reliable numerical ages, and the present investigation suggests adaptation of numerical details of the widely used Berggren et al [13] time scale in the early PaleoceDe.…”

Section: Morozovel/a Trlnidadensis Zonementioning

confidence: 99%

Magnetostratigraphy of the Cretaceous-Tertiary boundary at Agost (Spain)

Groot

Jonge

Langereis³

et al. 1989

Earth and Planetary Science Letters

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A detailed magnetostratigraphic investigation of the Agost section (Spain) containing the Cretaceous-Tertiary (K/T) boundary is reported. Thermal demagnetization--contrary to alternating field demagnetization--succeeds in revealing the polarity of the characteristic remanent magnetization, although an overlap in blocking temperature spectrum exists with a normal polarity, secondary magnetization component. The K/T boundary occurs at two-thirds from the base of a reversed polarity zone and by comparison with earlier results [1] this polarity zone is correlated to chron C29r.Linear regression of sedimentation rates in other sections with an established magnetostratigraphy and containing the K/T boundary yields an age of 66.45 Ma for this boundary. On the basis of this age and the magnetic reversal ages of the Berggren et al. [13]

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Terminal Cretaceous Environmental Events

Cited by 231 publications

References 75 publications

Platinum group elements and gold in ferromanganese crusts from Afanasiy-Nikitin seamount, equatorial Indian Ocean: Sources and fractionation

Platinum group elements and gold in ferromanganese crusts from Afanasiy-Nikitin seamount, equatorial Indian Ocean: Sources and fractionation

The reciprocal interaction of angiosperm evolution and tetrapod herbivory

Magnetostratigraphy of the Cretaceous-Tertiary boundary at Agost (Spain)

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