Magnetostratigraphic correlation of the Oxfordian–Kimmeridgian boundary

https://doi.org/10.1016/j.epsl.2009.11.014Get rights and content

Abstract

A magnetic polarity pattern for Boreal and Sub-Boreal ammonite zones of the Upper Oxfordian to Lower Kimmeridgian was established and confirmed in four British sections, including the proposed Global Boundary Stratotype Section and Point (GSSP) on the Isle of Skye (Scotland) to define the base of the international Kimmeridgian Stage. A coeval pattern for Sub-Mediterranean ammonite zones was compiled from seven sections in Poland, one German section and multi-section composites from France and Spain. The mean paleopole for the European Craton (excluding Spain) at the Oxfordian–Kimmeridgian boundary is 74.2°N, 181.3°E (Α95 = 3.8°). The common magnetic polarity scale enables inter-correlation of ammonite subzones among these three faunal provinces and to the marine magnetic-anomaly M-Sequence. The proposed GSSP at the base of the Pictonia baylei Zone is near the base of an extended interval dominated by reversed polarity, which is interpreted to be Chron M26r. This GSSP level projects to the lower to middle part of the Epipeltoceras bimammatum Subzone, which is the middle subzone of this E. bimammatum Zone in the Sub-Mediterranean standard zonation. In contrast, the traditional placement of the Oxfordian–Kimmeridgian boundary in that Sub-Mediterranean standard zonation (base of Sutneria platynota Zone) is at the base of Chron M25r, or nearly 1 million years younger.

Introduction

Ammonites and other marine fauna evolved during the Late Jurassic within separate climatic provinces in quasi-isolation. Each of these provinces has a high-resolution zonation based on ammonites, but it has been difficult to achieve an unequivocal correlation among these zonations except for rare intervals. This provincialism hindered the establishment of a Global boundary Stratotype Section and Point (GSSP) for the international Oxfordian–Kimmeridgian boundary, because such a GSSP should provide the means for precise global correlation. Traditionally, the base of the Kimmeridgian in the Boreal faunal province has been placed at the base of the ammonite Amoeboceras bauhini Zone, and in the Sub-Boreal province at the base of the Pictonia baylei Zone. However, in the Sub-Mediterranean province, the Kimmeridgian has a quite different definition and span, and traditionally began with the base of the ammonite Sutneria platynota Zone. Quantifying the offset between these competing regional definitions and an agreement on a standardized international Kimmeridgian has been a challenge.

A proposed international definition of the base of the Kimmeridgian within the British section in Flodigarry, at Staffin Bay, Isle of Skye (Wierzbowski et al., 2006, Matyja et al., 2006) was accepted in January, 2007, by over 70% of the Kimmeridgian Working Group of the Jurassic Subcommission of the International Commission on Stratigraphy (ICS). However, before a GSSP can be established, it is necessary to resolve how this level can be confidently correlated with other sections in the world. Therefore, in addition to biostratigraphy from unique evolutionary trends within multiple taxa groups, it is desirable to identify less-unique, but more global, non-biological stratigraphic tools, such as stable isotope excursions, major eustatic sea-level fluctuations or distinctive magnetic reversal horizons.

Magnetostratigraphy, combined with biostratigraphic constraints, can be a powerful tool for high-resolution correlation of stratigraphic sections. The M-sequence of marine magnetic anomalies spanning the Late Jurassic provides a reference polarity pattern and numerical time scale derived from seafloor spreading models (reviewed by Ogg and Smith in Gradstein et al., 2004). The presumed Kimmeridgian through Tithonian portion of this M-sequence (chrons M25r through M19n) is dominated by relatively long-duration polarity chrons. Magnetostratigraphic sections in condensed pelagic strata of southern Spain had indicated that the traditional placement of the “Oxfordian–Kimmeridgian boundary” within the Sub-Mediterranean faunal province was near polarity zone M25r (Ogg et al., 1984), but this level was suspected to be significantly younger than the classic “Oxfordian–Kimmeridgian boundary” of the Boreal faunal province. Marine magnetic anomalies older than Chron M25 are both closer spaced and lower in amplitude. Deep-tow magnetometer surveys in the Pacific Ocean have established a tentative polarity model extending into the Bathonian (Sager et al., 1998, Tivey et al., 2006, Tominaga et al., 2008), but this model remains uncalibrated owing to the lack of a complete and verified magnetic polarity time scale for the Bajocian through Oxfordian. Particularly vexing is the interval between anomalies M25r and M27r that has been interpreted from less precise sea-surface magnetic surveys and not yet verified by deep-tow magnetometer investigations.

We have utilized magnetostratigraphy based on over 900 paleomagnetic samples to establish an inter-regional correlation of the ammonite zones/subzones for Upper Oxfordian and Lower Kimmeridgian stages based on combination of the bio- and magnetostratigraphic results from the Boreal and Sub-Boreal temperate faunal provinces of Britain, and the Tethyan tropical faunal realm of Poland, France, Spain and Germany. Rare episodes of Boreal-fauna (cool) incursions into the Tethyan (warm) basins of Poland and Germany enable only a few inter-regional correlations limited to narrow stratigraphic intervals or horizons (e.g., Schweigert and Callomon, 1997, Matyja and Wierzbowski, 1997, Matyja and Wierzbowski, 2002, Matyja and Wierzbowski, 2006a, Matyja and Wierzbowski, 2006b, Matyja et al., 2006). Our correlation of magnetostratigraphies from these regions enables assignment of several precise horizons of inter-regional correlation, and provides a reference polarity pattern for the poorly-resolved marine magnetic anomalies between M25r and M27r. The proposed GSSP for the Oxfordian–Kimmeridgian boundary on the Isle of Skye (Wierzbowski et al., 2006, Matyja et al., 2006) nearly coincides with a distinctive polarity reversal that we correlate to the base of Chron M26r. The correlation to the M-Sequence chrons quantifies the approximate age, offset and duration of ammonite subzones and other datums among the different faunal provinces.

Section snippets

Magnetostratigraphic sections

Paleomagnetic minicores were drilled in most of the sections with an average spacing of 0.5 to 1 m. Denser samplings were near stage boundaries, within condensed intervals and close to hiatuses as determined by sequence stratigraphic analysis.

Demagnetization procedure

The suites of paleomagnetic samples from the British, Polish, French and German sections were analyzed in five laboratories (University of Michigan in USA, Lancaster University and Oxford University in Britain, GeoForschungsZentrum Potsdam and the University of Munich in Germany, and Polish Academy of Sciences). Remanent magnetization was measured using two- or three-axis cryogenic magnetometers.

The majority of samples from the Tethyan Realm (Poland, France and Germany) are limestones and

Calculation of paleomagnetic directions and paleopoles

Specimens rated as N, R, NP and RP were used to calculate mean directions, paleomagnetic poles and paleolatitudes, with their associated uncertainties. Mean directions were calculated separately for normal-, reversed- and combined-polarity directions using a weighted Fisher mean (Fisher, 1953) in which the NP and RP-rated specimens were given half-weight. In a second iteration, outliers of more than two circular standard deviations from the mean were excluded. For comparison, an additional mean

Boreal and Sub-Boreal composite

An integrated stratigraphy for each section was compiled with lithostratigraphy, magnetostratigraphy, selected sequence stratigraphy, and ammonite datums and associated zones (Fig. 4, Supplementary Figs. 2 through 4). The polarity pattern relative to ammonite subzones is generally quite consistent (Fig. 5). The uppermost Oxfordian is dominated by normal polarity. In contrast, the lowermost Kimmeridgian (sensu Boreal) is predominantly reversed polarity with two or three thin normal-polarity

Conclusions

The combined biostratigraphy and magnetostratigraphic results from sections in the Boreal, Sub-Boreal and Sub-Mediterranean outcrops allow a confident correlation of the Oxfordian–Kimmeridgian Stage boundary interval (as defined in Staffin Bay of the Isle of Skye) among these faunal provinces. The base of the Kimmeridgian, assigned in the GSSP as the base of the Amoeboceras bauhini and Pictonia baylei Zones, lies very close to the base of a reversed-polarity dominated interval. A similar

Acknowledgements

We thank Rob Van der Voo (University of Michigan, USA), Buffy McClelland (Oxford University, UK), Manfred Menning, Norbert Nowaczyk (GeoForschungsZentrum Potsdam, Germany) and Marek Lewandowski (Polish Academy of Sciences, Poland) for the use of their paleomagnetic laboratories, analytical software and technical support. We gratefully appreciate advice on paleomagnetic and lithostratigraphic interpretations by Piotr Ziόłkowski and Jacek Gutowski, and useful insights about the Plettenberg

References (54)

  • J. Bello et al.

    El límite de las Biozonas Transversarium y Bifurcatus (Oxfordiense Medio) en la Cordillera Ibérica nororiental: discontinuidades y lagunas estratigráficas asociadas

    Geogaceta

    (1995)
  • J. Besse et al.

    Apparent and true polar wander and the geometry of the geomagnetic field over the last 200 Myr

    J. Geophys. Res.

    (2002)
  • R.F. Butler

    Paleomagnetism: Magnetic Domains to Geologic Terrains

  • G. Cairanne et al.

    Laboratory chemical remanent magnetization in a natural claystone: a record of two magnetic polarities

    Geophys. J. Int.

    (2004)
  • Coe, A.L., 1992. Unconformities within the Upper Jurassic of the Wessex Basin, Southern England. Ph.D. dissertation....
  • A.L. Coe

    A comparison of the Oxfordian successions of Dorset, Oxfordshire, and Yorkshire

  • B.M. Cox

    A review of Jurassic chronostratigraphy and age indicators for the U.K

  • B.M. Cox

    South Ferriby

  • P. Dagley et al.

    Magnetic polarity stratigraphy of the Tertiary igneous rocks of Skye, Scotland

    Geophys. J. Int.

    (1990)
  • B.B. Ellwood et al.

    Anomalous magnetic properties in rocks containing the mineral siderite: paleomagnetic implications

    J. Geophys. Res.

    (1986)
  • R.A. Fisher

    Dispersion on a sphere

    Proc. R. Soc. Lond., A

    (1953)
  • D.E. France et al.

    Identifying goethite and hematite from rock magnetic measurements of soils and sediments

    J. Geophys. Res.

    (2000)
  • E. Głowniak

    Correlation of the zonal schemes at the late Middle to early Late Oxfordian boundary (Jurassic) in the Submediterranean Province: Poland and Switzerland

    Acta Geol. Pol.

    (2006)
  • Hantzpergue, P., Atrops, F., Enay, R., 1997. 10. — Kimméridgien, in: Groupe Français d'Étude du Jurassique (coordinated...
  • M.T. Juárez et al.

    Oxfordian magnetostratigraphy in the Iberian Range

    Geophys. Res. Lett.

    (1995)
  • J.L. Kirschvink

    The least-squares line and plane and the analysis of palaeomagnetic data

    Geophys. J. R. Astron. Soc.

    (1980)
  • B.A. Matyja et al.

    Syborowa Hill, ammonite succession at Middle/Upper Oxfordian boundary; upper Bifurcatus and lower Bimammatum Zones

  • Cited by (19)

    • Unravelling Middle to Late Jurassic palaeoceanographic and palaeoclimatic signals in the Hebrides Basin using belemnite clumped isotope thermometry

      2020, Earth and Planetary Science Letters
      Citation Excerpt :

      This succession is thus an ideal candidate for a reconstruction of Middle to Late Jurassic temperatures (e.g. Wierzbowski, 2004; Nunn et al., 2009). In addition to the pristine preservation of the biogenic calcite and organic matter, there is an excellent biostratigraphic scheme (Sykes and Callomon, 1979; Riding and Thomas, 1997; Hesselbo and Coe, 2000; Barski, 2018 and references therein), supported by Re-Os radioisotope ages (Selby, 2007) and magnetostratigraphy (Przybylski et al., 2010). The stratigraphy of the Callovian to Kimmeridgian strata at Staffin Bay, Trotternish, consists of the lower Callovian Staffin Bay Formation, the oyster-rich shales of the Upper Ostrea Member, overlain by the conspicuous Belemnite Sands Member, a well-cemented and belemnite-rich siltstone and sandstone bed at the top of the formation (Morton and Hudson, 1995; Hesselbo and Coe, 2000).

    • Geomagnetic Polarity Time Scale

      2020, Geologic Time Scale 2020
    • The Jurassic Period

      2020, Geologic Time Scale 2020
    • An expanded Tethyan Kimmeridgian magneto-biostratigraphy from the S'Adde section (Sardinia): Implications for the Jurassic timescale

      2018, Palaeogeography, Palaeoclimatology, Palaeoecology
      Citation Excerpt :

      Accepting the Tethyan Kimmeridgian, as defined at S'Adde, between the FO of F. multicolumnatus and the FO of C. mexicana minor (Casellato et al., 2012), allows direct magnetostratigraphic correlation via a relatively simple sedimentation rate function (Fig. 9) to the M-sequence (Malinverno et al., 2012) between ~152.8 Ma and ~146.5 Ma. In the Flodigarry candidate GSSP from Scotland (Fig. 7), the base of the Sub-Boreal Kimmeridgian is placed at the base of the P. baylei Sub-Boreal Ammonite Zone that is tentatively correlated using magnetostratigraphy combined with the tentative Re-Os age estimate of 154.1 ± 2.2 Ma from Selby (2007) to the M27/M26 polarity Chron boundary (Przybylski et al., 2010; Wierzbowski et al., 2016). The M27/M26 Chron boundary falls at 153.45 Ma on the Malinverno et al. (2012) M-sequence, in agreement with the Re-Os age, and <1 Myr older than the FO of F. multicolumnatus that defines the base of the Kimmeridgian in the Tethys realm (Fig. 10, see S'Adde vs target M-sequence correlation).

    • The dinosaur tracksite of Loulle (early Kimmeridgian; Jura, France)

      2016, Geobios
      Citation Excerpt :

      This dinosaur-tracks interval of biolaminites is located in the upper part of the Morillon Formation (Énay, 1966) and attributed to the Hauffianum Subzone (Bimammatum Zone) of the submediterranean ammonite zonation (Fig. 4). Recent correlations between subboreal and submediterranean ammonite zonations show that the Hauffianum Subzone is equivalent to the Densicostata Subzone (Baylei Zone) of the subboreal chart (Przybylski et al., 2010; Wright, 2010; Matyja and Wierzbowski, 2000, 2003; Schweigert and Callomon, 1997; Énay et al., 2014). The dinosaur tracksite of Loulle can thus be located at the base of the Kimmeridgian Stage, ca. 157 M.a. ago (Fig. 4).

    • Geomagnetic polarity time scale

      2012, The Geologic Time Scale 2012
    View all citing articles on Scopus
    1

    Now at BP America Inc., Southern Performance Unit, 501 Westlake Park Blvd., Houston, TX 77079, USA. Tel.: +1 281 366 1603.

    View full text