Integrated chronostratigraphic calibration of the Oligocene-Miocene boundary at 24.0 ± 0.1 Ma from the CRP-2A drill core, Ross Sea, Antarctica
University of Otago1, University of Cambridge2, New Mexico Institute of Mining and Technology3, University of Southampton4, University of Nebraska–Lincoln5, University of Parma6, University of California, Santa Cruz7, University of Queensland8, National Institute of Geophysics and Volcanology9, GNS Science10, Northern Illinois University11, University of California, Davis12
TL;DR: In this paper, an expanded Oligocene-Miocene boundary interval recovered in the Cape Roberts Project CRP-2A core from beneath the Ross Sea, Antarctica, has yielded a high-resolution integrated chrono stratigraphy that has, in turn, enabled a new, more direct, calibra tion of magnetic polarity and biostratigraphic events.
Abstract: An expanded Oligocene-Miocene boundary interval recovered in the Cape Roberts Project CRP-2A core from beneath the Ross Sea, Antarctica, has yielded a high-resolution integrated chrono stratigraphy that has, in turn, enabled a new, more direct, calibra tion of magnetic polarity and biostratigraphic events. The Oligocene-Miocene boundary interval in the CRP-2A core comprises three ∼60-m-thick, rapidly deposited (>0.5 m/k.y.) sedimentary sequences (sequences 9, 10, and 11). In sequences 10 and 11, single-crystal, laser-fusion 40Ar/39Ar analyses of anorthoclase phenocrysts from two tephra horizons independently calibrate the CRP-2A magnetic-polarity stratigraphy and age model. Sequences 10 and 11 encompass subchron C6Cn.3n, which is dated as 24.3 ± 0.1 to 24.16 ± 0.1 Ma. Sequence 9 is interpreted to encompass subchron C6Cn.2n and the Oligocene-Miocene boundary, which is dated as 24.0 ± 0.1 Ma. These ages are ∼0.2 m.y. older than those of the geomagnetic polarity time scale calibrated from seafloor-spreading ridges and ∼0.9–1.3 m.y. older than the newly proposed astronomically calibrated ages. We contend that the discrepancy with the astronomically calibrated ages arises from a mismatch of three 406 k.y. eccentricity cycles or a 1.2 m.y. modulation of obliquity amplitude in the astronomical calibration of the Oligocene–Miocene time scale.
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TL;DR: In this paper, Pearson et al. provide an alphanumeric notation for Paleo-Eocene gene zones using the prefix "P" (for Paleocene), "E' (for Eocene) and "0"(for Oligocene) to achieve consistency with recent short-hand notation for other Cenozoic zones (Miocene ['M'], Pliocene [PL] and Pleistocene [PTD]).
Abstract: New biostratigraphic investigations on deep sea cores and outcrop sections have revealed several shortcomings in currently used tropical to subtropical Eocene plank tonic foraminiferal zonal schemes in the form of: 1) mod ified taxonomic concepts, 2) modifiel:l/different ranges of taxa, and 3) improved calibrations with magnetostratig raphy. This new information provides us with an op portunity to make some necessary improvements to ex isting Eocene biostratigraphic schemes. At the same time, we provide an alphanumeric notation for Paleo gene zones using the prefix 'P' (for Paleocene), 'E' (for Eocene) and '0' (for Oligocene) to achieve consistency with recent short-hand notation for other Cenozoic zones (Miocene ['M'], Pliocene [PL] and Pleistocene [PTD. Sixteen Eocene (E) zones are introduced (or nomen claturally emended) to replace the 13 zones and subzones of Berggren and others (1995). This new zonation serves as a template for the taxonomic and phylogenetic studies in the forthcoming Atlas of Eocene Planktonic Forami nifera (Pearson and others, in press). The 10 zones and subzones of the Paleocene (Berggren and others, 1995) are retained and renamed and/or emended to reflect im proved taxonomy and an updated chronologic calibra tion to the Global Polarity Time Scale (GPTS) (Berggren and others, 2000).' The PaleocenelEocene boundary is correlated with the lowest occurrence (LO) of Acarinina sibaiyaensis (base of Zone El), at the top of the trun cated and redefined (former) Zone P5. The five-fold zonation of the Oligocene (Berggren and others, 1995) is modified to a six-fold zonation with the elevation of (former) Subzones P21a and P21b to zonal status. The Oligocene (0) zomil' components are re named and/or nomenclaturally emended.
557 citations
TL;DR: In this article, the authors used the newly derived age of the Oligocene/Miocene (O/M) boundary of 23.0 Ma of Shackleton et al. (2000) 447, revised to the new astronomical calculation (La2003) of Laskar et al., to recalculate the spline ages of Cande and Kent (J. Geophys. Res. 100 (1995) 6093), and then tune the Site 1090 y 18 O record to obliquity using La2003.
128 citations
TL;DR: In this article, the Oligocene-Miocene proxy records from Ocean Drilling Program (ODP) Leg 154 were used to evaluate how the interaction of long, multi-million year beats in the Earth's eccentricity and obliquity are implicated in the waxing and waning of ice-sheets, presumably on Antarctica.
121 citations
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...H. Pälike et al. / Quaternary Science Reviews ] (]]]]) ]]]–]]] 3 Wilson et al. (2002)....
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TL;DR: In this article, the authors analyzed the Cenozoic sedimentary succession recovered at the CRP-1, CRP 2/2A and CRP 3 drill sites off Cape Roberts on the McMurdo Sound shelf, Antarctica, to reconstruct the palaeoclimate and the glacial history of this part of Antarctica.
101 citations
24 Mar 2009
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References
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TL;DR: 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.
Abstract: 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
3,582 citations
"Integrated chronostratigraphic cali..." refers background or methods in this paper
...…that the geomagnetic polarity time scale in the vicinity of the Oligocene-Miocene boundary was ;0.2 m.y. older than the conventional calibration of the geomagnetic polarity time scale (Cande and Kent, 1995) and 0.9–1.3 m.y. older than the astronomical calibration of Shackleton et al. (2000)....
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...We conclude that it is not possible to resolve *E-mail: Channell—jetc@ufl.edu; Martin—emartin@geology.ufl.edu. ages in the 23.5 to 25 Ma (C7–C6C) interval of the CK95 time scale (Cande and Kent, 1995) using strontium isotopes....
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...Ages are reported with respect to the time scale of Cande and Kent (1995)....
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01 Jan 1995
TL;DR: Cande and Kent as mentioned in this paper presented a revised (integrated magnetobiochronologic) Cenozoic time scale (IMBTS) based on an assessment and integration of data from several sources.
Abstract: Since the publication of our previous time scale (Berggren and others, 1985c = BKFV85) a large amount of new magneto- and biostratigraphic data and radioisotopic ages have become available. An evaluation of some of the key magnetobiostratigraphic calibration points used in BKFV85, as suggested by high precision 40 Ar/ 39 Ar dating (e.g., Montanari and others, 1988; Swisher and Prothero, 1990; Prothero and Swisher, 1992; Prothero, 1994), has served as a catalyst for us in developing a revised Cenozoic time scale. For the Neogene Period, astrochron- ologic data (Shackleton and others, 1990; Hilgen, 1991) required re-evaluation of the calibration of the Pliocene and Pleistocene Epochs. The significantly older ages for the Pliocene-Pleistocene Epochs predicted by astronomical calibrations were soon corroborated by high precision 40 Ar/ 39 Ar dating (e.g., Baksi and others, 1992; McDougall and others, 1992; Tauxe and others, 1992; Walter and others, 1991; Renne and others, 1993). At the same time, a new and improved definition of the Late Cretaceous and Cenozoic polarity sequence was achieved based on a comprehensive evaluation of global sea-floor magnetic anomaly profiles (Cande and Kent, 1992). This, in turn, led to a revised Cenozoic geomagnetic polarity time scale (GPTS) based on standardization to a model of South Atlantic spreading history (Cande and Kent, 1992/1995 = CK92/95). This paper presents a revised (integrated magnetobiochronologic) Cenozoic time scale (IMBTS) based on an assessment and integration of data from several sources. Biostratigraphic events are correlated to the recently revised global polarity time scale (CK95). The construction of the new GPTS is outlined with emphasis on methodology and newly developed polarity history nomenclature. The radioisotopic calibration points (as well as other relevant data) used to constrain the GPTS are reviewed in their (bio)stratigraphic context. An updated magnetobiostratigraphic (re)assessment of about 150 pre-Pliocene planktonic foraminiferal datum events (including recently avail- able high southern (austral) latitude data) and a new/modified zonal biostratigraphy provides an essentially global biostratigraphic correlation framework. This is complemented by a (re)assessment of nearly 100 calcareous nannofossil datum events. Unrecognized unconformities in the stratigraphic record (and to a lesser extent differences in taxonomic concepts), rather than latitudinal diachrony, is shown to account for discrep- ancies in magnetobiostratigraphic correlations in many instances, particularly in the Paleogene Period. Claims of diachrony of low amplitude (<2 my) are poorly substantiated, at least in the Paleocene and Eocene Epochs. Finally, we (re)assess the current status of Cenozoic chronostratigraphy and present estimates of the chronology of lower (stage) and higher (system) level units. Although the numerical values of chronostratigraphic units (and their boundaries) have changed in the decade since the previous version of the Cenozoic time scale, the relative duration of these units has remained essentially the same. This is particularly true of the Paleogene Period, where the Paleocene/Eocene and Eocene/Oligocene boundaries have been shifted ~2 my younger and the Cretaceous/Paleogene boundary ~1 my younger. Changes in the Neogene time scale are relatively minor and reflect primarily improved magnetobiostratigraphic calibrations, better understanding of chronostratigraphic and magnetobiostratigraphic relationships, and the introduction of a congruent astronom- ical/paleomagnetic chronology for the past 6 my (and concomitant adjustments to magnetochron age estimates).
3,122 citations
TL;DR: In this paper, the fitting of a straight line when both variables are subject to crrors is generalized to allow for correlation of the z and y errors, illustrated by reference to lead isochron fitting.
2,237 citations
TL;DR: In this article, the relative widths of the magnetic polarity intervals for the entire Late Cretaceous and Cenozoic have been systematically determined from magnetic profiles from the world's ocean basins.
Abstract: We have constructed a magnetic polarity time scale for the Late Cretaceous and Cenozoic based on an analysis of marine magnetic profiles from the world's ocean basins. This is the first time, since Heirtzler et al. (1968) published their time scale, that the relative widths of the magnetic polarity intervals for the entire Late Cretaceous and Cenozoic have been systematically determined from magnetic profiles. A composite geomagnetic polarity sequence was derived based primarily on data from the South Atlantic. Anomaly spacings in the South Atlantic were constrained by a combination of finite rotation poles and averages of stacked profiles. Fine-scale information was derived from magnetic profiles on faster spreading ridges in the Pacific and Indian Oceans and inserted into the South Ariantic sequence. Based on the assumption that spreading rates in the South Atlantic were smoothly varying but not necessarily constant, a time scale was generated by using a spline function to fit a set of nine age calibration points
1,408 citations
"Integrated chronostratigraphic cali..." refers background or methods in this paper
...…that the geomagnetic polarity time scale in the vicinity of the Oligocene-Miocene boundary was ;0.2 m.y. older than the conventional calibration of the geomagnetic polarity time scale (Cande and Kent, 1995) and 0.9–1.3 m.y. older than the astronomical calibration of Shackleton et al. (2000)....
[...]
...We conclude that it is not possible to resolve *E-mail: Channell—jetc@ufl.edu; Martin—emartin@geology.ufl.edu. ages in the 23.5 to 25 Ma (C7–C6C) interval of the CK95 time scale (Cande and Kent, 1995) using strontium isotopes....
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...Ages are reported with respect to the time scale of Cande and Kent (1995)....
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TL;DR: An improved and updated version of the statistical LOWESS fit to the marine 87Sr/86Sr record and a revised look-up table (V3:10/99; available from jmcarthur@ucl.ac.uk) is presented in this article.
Abstract: An improved and updated version of the statistical LOWESS fit to the marine 87Sr/86Sr record and a revised look-up table (V3:10/99; available from j.mcarthur@ucl.ac.uk) based upon it enables straightforward conversion of 87Sr/86Sr to numerical age, and vice versa, for use in strontium isotope stratigraphy (SIS). The table includes 95% confidence intervals on predictions of numerical age from 87Sr/86Sr. This version includes the Triassic and Paleozoic record (0509 Ma) omitted from previous versions because of the paucity of adequate data at the time of preparation. We highlight differences between the previous versions of the table and the current version and discuss some aspects of the 87Sr/86Sr record that may have geological significance. We give examples of how the table can be used and where it has proven useful.
1,303 citations
"Integrated chronostratigraphic cali..." refers background in this paper
...* 87Sr/86Sr age errors include the 2s measurement error, a 2s long-term laboratory error for standard determination (NIST-987 5 0.710249) and error in the LOWESS fit to the marine Sr curve of McArthur et al. (2001)....
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...The 87Sr/86Sr ages given for core CRP-2A (Lavelle, 2000; Wilson et al., 2002) are based on the 87Sr/86Sr age tables of McArthur et al. (2001)....
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