Steadying the rates

Langereis, Cor G.; Hoof, A.A.M. van; Hilgen, F.J.

doi:10.1038/369615a0

Cited by 18 publications

(12 citation statements)

References 10 publications

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“…Neogene astrochronology has significant implications for global variations in oceanic spreading rates. Wilson [1993] and Krijgsman et al [1999] found that the spreading rates implied by astronomical dating in the last 10 Ma were less variable than rates computed from the Cande and Kent [1992] GPTS; astronomical age control tends to steady spreading rates [see also Gordon , 1993; Baksi , 1994; Langereis et al , 1994; Krijgsman et al , 1999]. This observation supports the notion that minimizing global spreading rate fluctuations is a useful strategy to construct a GPTS [ Huestis and Acton , 1997].…”

Section: Introductionmentioning

confidence: 68%

M‐sequence geomagnetic polarity time scale (MHTC12) that steadies global spreading rates and incorporates astrochronology constraints

et al. 2012

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[1] Geomagnetic polarity time scales (GPTSs) have been constructed by interpolating between dated marine magnetic anomalies assuming uniformly varying spreading rates. A strategy to obtain an optimal GPTS is to minimize spreading rate fluctuations in many ridge systems; however, this has been possible only for a few spreading centers. We describe here a Monte Carlo sampling method that overcomes this limitation and improves GPTS accuracy by incorporating information on polarity chron durations estimated from astrochronology. The sampling generates a large ensemble of GPTSs that simultaneously agree with radiometric age constraints, minimize the global variation in spreading rates, and fit polarity chron durations estimated by astrochronology. A key feature is the inclusion and propagation of data uncertainties, which weigh how each piece of information affects the resulting time scale. The average of the sampled ensemble gives a reference GPTS, and the variance of the ensemble measures the time scale uncertainty. We apply the method to construct MHTC12, an improved version of the M-sequence GPTS (Late Jurassic-Early Cretaceous, $160-120 Ma). This GPTS minimizes the variation in spreading rates in a global data set of magnetic lineations from the Western Pacific, North Atlantic, and Indian Ocean NW of Australia, and it also accounts for the duration of five polarity chrons established from astrochronology (CM0r through CM3r). This GPTS can be updated by repeating the Monte Carlo sampling with additional data that may become available in the future.Citation: Malinverno, A., J. Hildebrandt, M. Tominaga, and J. E. T. Channell (2012), M-sequence geomagnetic polarity time scale (MHTC12) that steadies global spreading rates and incorporates astrochronology constraints,

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Section: Introductionmentioning

confidence: 68%

M‐sequence geomagnetic polarity time scale (MHTC12) that steadies global spreading rates and incorporates astrochronology constraints

et al. 2012

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“…[1990] and Hilgen [1991] with a refined astronomical age recently suggested for the Gauss/Matuyama boundary by Langereis et al [1994]. The revised geomagnetic polarity timescale is listed in Tables 2 and 3.…”

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confidence: 99%

Revised calibration of the geomagnetic polarity timescale for the Late Cretaceous and Cenozoic

Cande¹,

Kent²

1995

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Recently reported radioisotopic dates and magnetic anomaly spacings have made it evident that modification is required for the age calibrations for the geomagnetic polarity timescale of Cande and Kent (1992) at the Cretaceous/Paleogene boundary and in the Pliocene. An adjusted geomagnetic reversal chronology for the Late Cretaceous and Cenozoic is presented that is consistent with astrochronology in the Pleistocene and Pliocene and with a new timescale for the Mesozoic. The age of 66 Ma for the Cretaceous/Paleogene (K/P) boundary used for calibration in the geomagnetic polarity timescale of Cande and Kent [1992] (hereinafter referred to as CK92) was supported by high precision laser fusion Ar/Ar sanidine single crystal dates from nonmarine strata in Montana. However, these age determinations are now considered to be anomalously old due to problems with sample preparation [Swisher et al., 1992, 1993]. A consensus is developing for an age of 65 Ma for the K/P boundary as recorded in marine [Swisher et al., 1992; Dalryrnple et al., 1993] and nonmarine [Swisher et al., 1993] sediments, and the 65 Ma age has been adopted, for example, as an anchor point in the Mesozoic timescale of Gradstein et al. [1994]. Astrochronologic control for the geomagnetic polarity timescale has been developed by Shackleton et al. [1990] and Hilgen [1991] for the Pleistocene and Pliocene to the base of the Thvera polarity subchron (subchron C3n.4n) and has been confirmed to about 3.3 Ma using high-precision At/At dating [Renne et al., 1993]. The astronochronologic estimates for the Brunhes/Matuyama (0.78 Ma) and Matuyama/Gauss (2.60 Ma) boundaries were already used for calibration in CK92; thus the good agreement of CK92 with the astronomical timescale to the older end of chron C2A (Gauss/Gilbert boundary) is not unexpected. An appreciable discrepancy, however, emerges in the early Pliocene where the astronomical timescale gives ages for the constituent polarity intervals of chron C3n (C3n. ln, C3n.2n, C3n.3n, and C3n.4n, or Cochiti, Nunivak, Sidufjall, and Thvera subchrons, respectively) that are systematically 150 to 180 kyr older than the interpolated ages in CK92. Wilson [1993] showed that the astrochronology gives a more consistent seafloor spreading history when applied to his revised spacings of anomalies on several Pacific spreading ridges. This points to the magnetic anomaly spacings for this interval used for interpolation by Cande and Kent [1992] as the likely source of the discrepancy and suggests that the available astronochronology provides reliable ages for polarity chrons through the Pliocene (see also Renne et al., 1994).Copyfight 1995 by tho Amorican Ooophysical Union.

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“…Stability in chronometric timescales is less easily achieved and depends, among others, on caution not to publish new timescales on a too frequent basis (see also Berggren et al, 1995). Such a stability is now within reach for the youngest part of the Earth's history because astronomical timescales attain a permanent character and need to undergo no or only minor revisions in the future (e.g., Langereis et al, 1994;Lourens et al, 1996), thus avoiding the promulgation of new and fundamentally different timescales. For the Plio-Pleistocene, the astronomical timescale is now well established and accepted as a standard (Cande and Kent, 1995;Berggren et al, 1995).…”

Section: Introductionmentioning

confidence: 99%

Integrated stratigraphy and astronomical calibration of the Serravallian/Tortonian boundary section at Monte Gibliscemi (Sicily, Italy)

Hilgen

Krijgsman²,

Raffi

et al. 2000

Marine Micropaleontology

117

148

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Results are presented of an integrated stratigraphic (calcareous plankton biostratigraphy, cyclostratigraphy and magnetostratigraphy) study of the Serravallian=Tortonian (S=T) boundary section of Monte Gibliscemi (Sicily, Italy). Astronomical calibration of the sedimentary cycles provides absolute ages for calcareous plankton bio-events in the interval between 9.8 and 12.1 Ma. The first occurrence (FO) of Neogloboquadrina acostaensis, usually taken to delimit the S=T boundary, is dated astronomically at 11.781 Ma, pre-dating the migratory arrival of the species at low latitudes in the Atlantic by almost 2 million years. In contrast to delayed low-latitude arrival of N. acostaensis, Paragloborotalia mayeri shows a delayed low-latitude extinction of slightly more than 0.7 million years with respect to the Mediterranean (last occurrence (LO) at 10.49 Ma at Ceara Rise; LO at 11.205 Ma in the Mediterranean). The Discoaster hamatus FO, dated at 10.150 Ma, is clearly delayed with respect to the open ocean. The ages of D. kugleri first and last common occurrence (FCO and LCO), Catinaster coalitus FO, Coccolithus miopelagicus last (regular) occurrence (L(R)O) and the D. hamatus=neohamatus cross-over, however, are in good to excellent agreement with astronomically tuned ages for the same events at Ceara Rise (tropical Atlantic), suggesting that both independently established timescales are consistent with one another. The lack of a reliable magnetostratigraphy hampers a direct comparison with the geomagnetic polarity timescale of Cande and Kent (1995; CK95), but ages of calcareous nannofossil events suggests that CK95 is significantly younger over the studied time interval. Approximate astronomical ages for the polarity reversals were obtained by exporting astronomical ages of selected nannofossil events from Ceara Rise (and the Mediterranean) to eastern equatorial Pacific ODP Leg 138 Site 845, which has a reliable magnetostratigraphy.Our data from the Rio Mazzapiedi-Castellania section reveal that the base of the Tortonian stratotype corresponds almost exactly with the first regular occurrence (FRO) of N. acostaensis s.s. as defined in the present study, dated at 10.554 Ma. An extrapolated age of 11.8 Ma calculated for the top of the Serravallian stratotype indicates that there is a gap between the top of the Serravallian and the base of the Tortonian stratotype, potentially rendering all bio-events in the interval between 11.8 and 10.554 Ma suitable for delimiting the S=T boundary. Despite the tectonic deformation and the lack of a magnetostratigraphy, Gibliscemi remains a candidate to define the S=T boundary by means of the Tortonian global boundary stratotype section and point (GSSP). © 2000 Elsevier Science B.V. All rights reserved.Ł Corresponding author. E-mail: fhilgen@geo.uu.nl 0377-8398/00/$ -see front matter © 2000 Elsevier Science B.V. All rights reserved. PII: S 0 3 7 7 -8 3 9 8 ( 0 0 ) 0 0 0 0 8 -6 182 F.J. Hilgen et al. / Marine Micropaleontology 38 (2000)

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Steadying the rates

Cited by 18 publications

References 10 publications

M‐sequence geomagnetic polarity time scale (MHTC12) that steadies global spreading rates and incorporates astrochronology constraints

M‐sequence geomagnetic polarity time scale (MHTC12) that steadies global spreading rates and incorporates astrochronology constraints

Revised calibration of the geomagnetic polarity timescale for the Late Cretaceous and Cenozoic

Integrated stratigraphy and astronomical calibration of the Serravallian/Tortonian boundary section at Monte Gibliscemi (Sicily, Italy)

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