A revised Cenozoic geochronology and chronostratigraphy
01 Jan 1995-Vol. 54, pp 129-212
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).
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TL;DR: The boron-isotope ratios of ancient planktonic foraminifer shells are used to estimate the pH of surface-layer sea water throughout the past 60 million years, which can be used to reconstruct atmospheric CO2 concentrations.
Abstract: Knowledge of the evolution of atmospheric carbon dioxide concentrations throughout the Earth's history is important for a
reconstruction of the links between climate and radiative forcing of the Earth's surface temperatures. Although atmospheric
carbon dioxide concentrations in the early Cenozoic era (about 60Myr ago) are widely believed to have been higher than at present,
there is disagreement regarding the exact carbon dioxide levels, the timing of the decline and the mechanisms that are most
important for the control of CO2 concentrations over geological timescales. Here we use the boron-isotope ratios of ancient
planktonic foraminifer shells to estimate the pH of surface-layer sea water throughout the past 60 million years, which can be used
to reconstruct atmospheric CO2 concentrations. We estimate CO2 concentrations of more than 2,000 p.p.m. for the late Palaeocene
and earliest Eocene periods (from about 60 to 52 Myr ago), and ®nd an erratic decline between 55 and 40 Myr ago that may have
been caused by reduced CO2 outgassing from ocean ridges, volcanoes and metamorphic belts and increased carbon burial. Since
the early Miocene (about 24Myr ago), atmospheric CO2 concentrations appear to have remained below 500 p.p.m. and were more
stable than before, although transient intervals of CO2 reduction may have occurred during periods of rapid cooling approximately
15 and 3 Myr ago.
1,623 citations
01 Jan 1998
TL;DR: In this paper, the authors presented a state-of-the-art biochronostratigraphic record of depositional sequences in European basins for the Mesozoic and Cenozoic.
Abstract: Under the auspices of the "Mesozoic-Cenozoic Sequence Stratigraphy of European Basins" project (MCSSEB) an attempt was' made to construct a state-of-the-art biochronostratigraphic record of depositional sequences in European basins for the Mesozoic and Cenozoic. A wellcalibrated regional biochronostratigraphic framework is seen as an essential step towards an eventual demonstration of synchroneity of sequences in basins with different tectonic histories. The Mesozoic sequence stratigraphic and biostratigraphic records for the project (MCSSEB) are calibrated to the Gradstein et al. (1994) temporal scale. The Cenozoic record is calibrated to the Berggren et al. (1995) scale. The primary calibration in the Mesozoic between temporal and standard stratigraphy is based on ammonite biostratigraphy. This calibration was facilitated by h integration of the composite ammonite zonation of the "Sequence Stratigraphy of European Basins" project with the standard stratigraphy, magnetostratigraphy and radiometric data for the Triassic through lower Cretaceous intervals in the Gradstein et al. (1994) time scales. The Triassic through lower Cretaceous composite ammonite zonation in Gradstein et al. (1994) includes the highest resolution, zonal or subzonal, ammonite subdivisions available from tethyan as well as boreal areas in Europe. For the upper Cretaceous, Gradstein et al. (1994) calibrated their temporal scale with the Cobban et al. (1994) ammonite record from the Western Interior Basin in the United States, which is well correlated with 40Ar/39Ar dates from bentonites incorporated in the Obradovich (1993) and Gradstein et al. (1994) time scales. Calibration of the upper Cretaceous Western Interior Basin ammonite record with the European succession is relatively well understood for the Cenomanian through Santonian Stages but largely unresolved for the Campanian and Maastrichtian Stages. An incomplete ammonite record in the type areas in Europe and the lack of calibration between zonations of "cosmopolitan" fossil groups such as planktonic foraminifera, calcareous nannofossils and endemic ammonites in North America as well as Europe prevent adequate correlation. Calibration in the Cenozoic between temporal and standard stratigraphy is based on an integrated framework of magnetostratigraphy, planktonic foraminifera and calcareous nannofossils and selected radiometric ages. Subsequent calibration of sequences, strontium isotope ratios (87Sr/86Sr), oxygen isotope events, and additional fossil groups from oceanic, near shore and non-marine environments, was carried out by a large number of coordinators and contributors. INTRODUCTION was reviewed at workshops in Paris in May and December 1991 ~h~ chronostratigraphic charts presented in this paper are the and a preliminary biochronostratigraphic framework calibrated result of an initiative by Peter Vail and Thieny Jacquin in 1990 to the Haq et al. (1987) time scale was resented at the ~ i j o n to analyze and document depositional sequences in E~~~~~~~ Conference in 1992. After completion of the Gradstein et al. basins and to record their stratigraphic position relative to a (1994) Mesozoic time scale and the ~ e r ~ ~ r e n et al. (1995) Cestate-of-the-art temporal framework accurately calibrated to a ~ O Z O ~ C time scale, all biostratigraphic, isotope stratigraphic and biostratigraphic framework. ~h~ ~ ~ M e s o z o ~ c ~ e n o z o ~ c sesequence stratigraphic entries were recalibrated to the new time quence Stratigraphy of European Basins" project started officially with a meeting in ~ i j o n France organized by Jacquin, de Gracianskv, and Vail. in Mav 1992. Secluence interpretations SEISMIC STRATIGRAPHYISEQUENCE STRATIGRAPHY for a large number of European basins were presented at poster Mitchum et al. (1977) described the depositional sequence sessions in Dijon. Papers in this volume, many of them based as a basic unit for stratigraphic analysis with chronostration the Dijon posters, form an integral part of the sequence documentation for the chronostratigraphic charts. Work on the detailed chronostratigraphic charts for the Mesozoic and Cenozoic began eighteen months before the Dijon Meeting, in December 1990 in Paris with a planning meeting attended by a large number of specialists in a wide range of biostratigraphic disciplines from several European countries. At the Paris meeting, all specialists present were invited to participate in the calibration of fossil groups representing non-marine, shallowand deep-water depositional environments to a revised temporal framework. Invitations were extended to specialists not present at the Paris meeting to complement the expertise in fossil groups essential to the construction of a stratigraphic framework and to the calibration of sequences. Progress graphic significance. They defined the depositional sequence as follows: "A depositional sequence is a stratigraphic unit composed of a relatively conformable succession of genetically related strata and bounded at its top and base by unconformities or their correlative conformities." This definition adds the concept of the "correlative conformity" to the unconformitybounded sequence in the sense of Sloss (1963). Adding the "correlative conformity" to the sequence definition is essential to allow application of sequence stratigraphy in areas of continuous deposition. Even though Mitchum et al. (1977) discussed the chronostratigraphic significance of their sequence, they defined the sequence as a lithologic unit ("A depositional sequence is determined by a single objective criterion, the physical relations of the strata themselves)." They stopped, s Mesozoic and Cenozoic Sequence Stratigraphy of European Basins, SEPM Special Publication N.o. 60 Copyright
1,507 citations
Cites background or methods from "A revised Cenozoic geochronology an..."
...Sequences are positioned relative to the Berggren et al. (1995) temporal framework primarily with calcareous nannofossils and planktonic foraminifera (Chart 2)....
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...…de Montpellier II, 34095 Montpellier, Cedex 05, France The rnagnetobiostratigraphic/chronologic franaework presented here draws from the recent revision to the Cenozoic time scale by Berggren et al. (1995a) for the Paleocene to Miocene and by Berggren et al. (1995b) for the Pbcene and Pleistocene....
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...The calibration of Pliocene and Pleistocene calcareous nannofossil datums in Berggren et al. (1995b) is based on the studies of Backman and Shackleton (1983), Backman and Pestiaux (1987), Berggren et al. (1983)....
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...The calibration of Paleogene datums herein relies primarily on DSDP Holes 384 (Aubry in Berggren et al., 1995a), 527 (Shackleton et al., 1984) and 577 (Monecchi et al., 1985) for the Paleocene; on DSDP Holes 516 (Berggren et al., 1983a; Wei and Wise, 1989), 522,523 (Poore et al., 1982,1983),…...
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...Cenozoic Time Scale The Cenozoic time scale (Berggren et al., 1995) integrates an extensive DSDPIODP record on magnetostratigraphy, planktonic foraminifera and calcareous nannofossil biostratigraphy and standard stratigraphy with selected radiometric dates to produce a well-calibrated temporal…...
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01 Jan 2012
TL;DR: An Astronomically Tuned Neogene Time Scale (ATNTS2012) is presented in this article, as an update of ATNTS2004 in GTS2004, and the numerical ages are identical or almost so.
Abstract: An Astronomically Tuned Neogene Time Scale (ATNTS2012) is presented, as an update of ATNTS2004 in GTS2004. The new scale is not fundamentally different from its predecessor and the numerical ages are identical or almost so. Astronomical tuning has in principle the potential of generating a stable Neogene time scale as a function of the accuracy of the La2004 astronomical solution used for both scales. Minor problems remain in the tuning of the Lower Miocene. In GTS2012 we will summarize what has been modified or added since the publication of ATNTS2004 for incorporation in its successor, ATNTS2012. Mammal biostratigraphy and its chronology are elaborated, and the regional Neogene stages of the Paratethys and New Zealand are briefy discussed. To keep changes to ATNTS2004 transparent we maintain its subdivision into headings as much as possible.
1,479 citations
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
Cites background from "A revised Cenozoic geochronology an..."
...According to the time scale of Berggren et al. (1995) , this equates to the lower part of Chron C5Dr, to the lowermost part of zone NN4 of the calcareous nannofossil zonation of Martini (1971), the middle of zone N6 of the planktonic foraminiferal zonation of Blow (1969), and so on....
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...Figure 4. LOWESS data for the period 18‐28 Ma. Time scale of Berggren et al. (1995) ....
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...According to the time scale of Berggren et al. (1995), this equates to the lower part of Chron C5Dr, to the lowermost part of zone NN4 of the calcareous nannofossil zonation of Martini (1971), the middle of zone N6 of the planktonic foraminiferal zonation of Blow (1969), and so on....
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TL;DR: It is proposed that intrusion of voluminous mantle-derived melts in carbon-rich sedimentary strata in the northeast Atlantic may have caused an explosive release of methane—transported to the ocean or atmosphere through the vent complexes—close to the Palaeocene/Eocene boundary.
Abstract: A 200,000-yr interval of extreme global warming marked the start of the Eocene epoch about 55 million years ago. Negative carbon- and oxygen-isotope excursions in marine and terrestrial sediments show that this event was linked to a massive and rapid (approximately 10,000 yr) input of isotopically depleted carbon. It has been suggested previously that extensive melting of gas hydrates buried in marine sediments may represent the carbon source and has caused the global climate change. Large-scale hydrate melting, however, requires a hitherto unknown triggering mechanism. Here we present evidence for the presence of thousands of hydrothermal vent complexes identified on seismic reflection profiles from the Voring and More basins in the Norwegian Sea. We propose that intrusion of voluminous mantle-derived melts in carbon-rich sedimentary strata in the northeast Atlantic may have caused an explosive release of methane--transported to the ocean or atmosphere through the vent complexes--close to the Palaeocene/Eocene boundary. Similar volcanic and metamorphic processes may explain climate events associated with other large igneous provinces such as the Siberian Traps (approximately 250 million years ago) and the Karoo Igneous Province (approximately 183 million years ago).
902 citations
References
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01 Jan 1995
TL;DR: A well-constructed geochronologic framework that allows estimation of rates of geologic processes, correlation of stratigraphies, and placement of discrete events in temporal order is presented in this paper.
Abstract: Geochronology, Time Scales, and Global Stratigraphic Correlation - The last decade has witnessed significant advances in analytic techniques and methodologic approaches to understanding earth history. This publication is a well-constructed geochronologic framework that allows estimation of rates of geologic processes, correlation of stratigraphies, and placement of discrete events in temporal order. Resulting from a research symposium at the 67th Annual SEPM meeting in New Orleans, Louisiana, April 1993, the 16 papers of this volume represent a broad spectrum of approaches to understanding earth history and the passage of geologic time.
1,042 citations