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Filey Brigg (FB, Yorkshire) magnetostratigraphy with placement of main ammonite levels and interpretation of ammonite zonation. The meter scale is according to the regional composite of formation thicknesses. Polarity rating: N/R — good normal-or reversed-polarity behavior, INT — indeterminate or intermediate. Intensity column is for the computed vector for the characteristic direction of each sample. Abbreviations in ammonite columns: " plicat. " = Perisphinctes (Liorphinctes) plicatilis, " vertebr. " = Cardioceras (Vertebriceras) vertebrale, " Card. " = Cardioceras, " mar. " = Quenstedtoceras mariae, " prae. " = Cardioceras praecordatum. In Member column, " Hm. Ool. (Up. Leaf) " = Hambleton Oolite (Upper Leaf) member.
Source publication
A suite of 11 sections through the Oxfordian (Upper Jurassic) strata in the Dorset and Yorkshire regions of England and the Isle of Skye in Scotland yielded magnetic polarity patterns directly calibrated to the ammonite biostratigraphy of the Boreal and the Subboreal faunal provinces. The sections include the leading candidate for the global strato...
Context in source publication
Context 1
... suite of sections from Dorset, Yorkshire and the Isle of Skye enables compilation of a consistent composite polarity scale for the Oxfordian of Britain. The main polarity zones, consisting of clusters of samples having similar polarity, are generally well-delimited for each section ( Figs. 3-7; Suppl. Figs. 2-6). Ammonite subzones of the Boreal and Subboreal faunal provinces have been inter-correlated and provide the primary means to correlate the main polarity zones. Regional sequence stratigraphy interpretations (e.g., Coe, 1992Coe, , 1995 are guides to potential stratigraphic gaps or condensation in the successions. The ...
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The first compiled composite section comprises continuous succession of upper Tithonian-lower Berriasian strata (Jacobi Zone) from different isolated outcrops of the Feodosiya area. Based on new magnetostratigraphic and sedimentological data, the paleomagnetic section is correlated with succession of M20r, M19n, M19r, M18b chrons and M18n.1r Subchr...
Citations
... Correlation of UK sections, allowing construction of a Subboreal composite magnetostratigraphy and refinement of some of the details in poorly sampled parts of the Flodigarry section either side of the boundary interval (fromWierzbowski A. et al., 2016). Other section details and chron names (i.e., BB) on the British magnetic polarity composite fromPrzybylski et al. (2010). Chrons BB4 and BB5 ofPrzybylski et al. (2010) have been merged into chron BB5-4, since BB4r was based only on a single specimen from the Evoluta Subzone at South Ferriby,Yorkshire, UK. al., 2005;Wierzbowski A. et al., 2006;Nunn et al., 2009). ...
... Other section details and chron names (i.e., BB) on the British magnetic polarity composite fromPrzybylski et al. (2010). Chrons BB4 and BB5 ofPrzybylski et al. (2010) have been merged into chron BB5-4, since BB4r was based only on a single specimen from the Evoluta Subzone at South Ferriby,Yorkshire, UK. al., 2005;Wierzbowski A. et al., 2006;Nunn et al., 2009). ...
... Several groups have reported Jurassic geomagnetic field reversals from terrestrial magnetostratigraphy (Ogg & Gutowski, 1995;Steiner et al., 1985Steiner et al., , 1987, confirming polarity reversals during the M25-M38 period (Ogg et al., 2010;Przybylski, Głowniak, et al., 2010;Przybylski, Ogg, et al., 2010). More recent magnetostratigraphic and rock magnetic studies from European and South American basins also show magnetic reversals deeper in time, M38-M44 (e.g., Gipe, 2013;Llanos et al., 2019). ...
... Several groups have reported Jurassic geomagnetic field reversals from terrestrial magnetostratigraphy (Ogg & Gutowski, 1995;Steiner et al., 1985Steiner et al., , 1987, confirming polarity reversals during the M25-M38 period (Ogg et al., 2010;Przybylski, Głowniak, et al., 2010;Przybylski, Ogg, et al., 2010). More recent magnetostratigraphic and rock magnetic studies from European and South American basins also show magnetic reversals deeper in time, M38-M44 (e.g., Gipe, 2013;Llanos et al., 2019). ...
The Geomagnetic Polarity Time Scale (GPTS) provides a basis for the geological timescale, quantifies geomagnetic field behavior, and gives a time framework for geologic studies. We build a revised Middle to Late Jurassic GPTS by using a new multiscale magnetic profile, combining sea surface, midwater, and autonomous underwater vehicle near‐bottom magnetic anomaly data from the Hawaiian lineation set in the Pacific Jurassic Quiet Zone (JQZ). We correlate the new profile with a previously published contemporaneous magnetic sequence from the Japanese lineation set. We then establish geomagnetic polarity block models as a basis for our interpretation of the origin and nature of JQZ magnetic anomalies and a GPTS. A significant level of coherency between short‐wavelength anomalies for both the Japanese and Hawaiian lineation magnetic anomaly sequences suggests the existence of a regionally coherent field during this period of rapid geomagnetic reversals. Our study implies the rapid onset of the Mesozoic Dipole Low from M42 through M39 and then a subsequent gradual recovery in field strength into the Cenozoic. The new GPTS, together with the Japanese sequence, extends the magnetic reversal history from M29 back in time to M44. We identify a zone of varying, difficult‐to‐correlate anomalies termed the Hawaiian Disturbed Zone, which is similar to the zone of low amplitude, difficult‐to‐correlate anomalies in the Japanese sequence termed the Low Amplitude Zone (LAZ). We suggest that the LAZ, bounded by M39–M41 isochrons, may in fact represent the core of what is more commonly known as the JQZ crust.
... andraeai FIGURE 26.9 Interregional correlation of latest Jurassic through earliest Cretaceous ammonite zones and regional stages. Magnetostratigraphic correlations to the marine magnetic anomaly M-sequence and cycle stratigraphy provide the reference numerical scale and absolute durations for Tethyan ammonite zones (e.g., Ogg et al., 2010a;Boulila et al., 2008bBoulila et al., , 2010aPruner et al., 2010). Sub-Boreal ammonite calibrations to Tethyan zone and/or M-sequence incorporates biostratigraphic unit. ...
... Scaling of Oxfordian ammonite zones and subzones by cycle stratigraphy (Boulila et al., 2008a(Boulila et al., , 2010a) enabled a better approximation of the durations of the polarity zones observed within each of those subzones. Therefore a composite magnetostratigraphy compiled from approximately 20 Oxfordian sections in Europe with partial cycle scaling verified the main features of the deep-tow pattern from M26 through M37 Ogg et al., 2010a). Chron M37n of that marine magnetic anomaly model was correlated to a Callo-vianÀOxfordian boundary using the lowest occurrence of Cardioceras redcliffense in GTS2012, but the current working definition for the base Oxfordian using the lowest occurrence of Cardioceras woodhamense would correlate to the lower part of Chron M36Br (Ogg et al., , 2011. ...
... Many of these fine-scale sequences appear to correspond to 405-kyr long-eccentricity-induced orbital-climate cycles. For example, the main sequences interpreted from carbonate-clay changes in the Lower Oxfordian of southern France and from sand-influxes and hiatuses in the lowerto-middle Oxfordian of the Dorset Coast (England) represent these 405-kyr orbital-climate oscillations (Boulila et al., 2010a;Ogg et al., 2010a). In this particular case a lowstand exposure in Dorset corresponds to an episode of carbonate-enrichment in the basinal successions of SE France. ...
Ammonites underwent an evolutionary diversification after the mass extinction of the end Triassic induced by the formation of a Large Igneous province (LIP), and this group provides the most useful marine biostratigraphy. Only two levels within the Jurassic are relatively well determined using U–Pb dating from single zircons in ash beds, at the base Hettangian and the Pliensbachian–Toarcian boundary. Otherwise the Lower Jurassic is scaled using astrochronology and the Middle and Upper Jurassic scaled from Pacific seafloor spreading rates correlated to magnetic reversals. LIP activity during the Early Jurassic (Triassic–Jurassic boundary and Toarcian) perturbed global environments to extents not evidenced since the end Permian, and age relationships allow for a strong causal connection between these LIP eruptions and mass extinctions caused by major paleoenvironmental change, including ocean anoxia. Breakup of the supercontinent Pangea dominated paleogeography and paleoceanography and created shallow seaways that form sources and traps for hydrocarbons. Calcareous planktonic algae diversified and migrated from shallow seaways to open oceans to set the stage for the beginning of modern oceanic biogeochemical cycling; calcareous nannofossils provide additional widely used correlation tools.
... Unlike the Cretaceous Normal Superchron (CNS), which is a well-defined, prolonged period of almost single polarity (i.e., no reversals) with strong field intensity [Prévot et al., 1990; Biggin et al., 2012; Tauxe, 2006; Tauxe et al., 2013], the JQZ appears starkly different. In contrast with the high field intensity of the CNS, bracketed by low reversal rates entering and leaving the superchron, the JQZ has low field intensity and high reversal rate [Ogg et al., 2010], while field intensity increases and reversal rate decreases exiting the period [Cande et al., 1978; Sager et al., 1998; McElhinny and Larson, 2003; Tivey et al., 2006; Tominaga et al., 2008]. ...
... Although the anomalously low field intensity during the JQZ is well documented by paleointensity data and appears to be the weakest field intensity of the past 400 Ma [Biggin et al., 2012; Tauxe et al., 2013], the existence of field reversals during the JQZ is still under debate. The most recent Oxfordian-Callovian (Middle to Late Jurassic) magnetostratigraphy [Ogg et al., 2010; Przybylski et al., 2010; Gipe, 2013] documents the terrestrial reversal record from M28 to M39 and confirms multiple reversals within the JQZ. Deep-tow magnetic data from the Japanese magnetic lineation set in the western Pacific JQZ crust (Figure 1) have been interpreted as a continuous record of magnetic reversals, extending back to M44 [Tominaga et al., 2008]. ...
... These deep-tow data revealed lineated magnetic anomalies throughout the time period from M38 to M44 [Tominaga et al., 2008; Gipe, 2013]. Magnetostratigraphic studies [Ogg et al., 2010; Przybylski et al., 2010; Gipe, 2013] correlate the terrestrial magnetic records to the polarity block models produced from the midwater level upward continued anomalies by Tominaga et al. [2008] and confirm that the Japanese M anomaly sequence contains magnetic reversals back to M39. The nature of the higher-frequency anomalies observed in the deep-tow profiles is still uncertain and may record either short-lived polarity periods or geomagnetic field intensity fluctuations [Tominaga et al., 2008]. ...
The nature of the Jurassic Quiet Zone (JQZ), a region of low amplitude oceanic magnetic anomalies, has been a long-standing debate with implications for the history and behavior of the Earth's geomagnetic field and plate tectonics. To understand the origin of the JQZ, we studied high-resolution sea-surface magnetic anomalies from the Hawaiian magnetic lineations and correlated them with the Japanese magnetic lineations. The comparison shows: (i) excellent correlation of anomaly shapes from M29 to M42; (ii) remarkable similarity of anomaly amplitude envelope, which decreases back in time from M19 to M38, with a minimum at M41, then increases back in time from M42; and (iii) refined locations of pre-M25 lineations in the Hawaiian lineation set. Based on these correlations, our study presents evidence of a regional and possible globally coherent pre-M29 magnetic anomalies in the JQZ and a robust extension of Hawaiian isochrons back to M42 in the Pacific crust.
... The distribution of microfossils in that section was briefly mentioned without the recognition of zones (Page et al. 2009a). The succession of palaeomagnetic reversals from the section (Ogg et al. 2010) shows numerous polarity oscillations, but nearly all such reversals are based on only one or two samples. The French candidate section near Thuoux has been recently described (Fortwengler et al. 2012). ...
During the last decade, three Russian sections have been proposed as global stratotype section and point (GSSP) candidates for the Callovian, Oxfordian, and Tithonian Stages. A comparison of these sections with other GSSP candidate sections in relation to their fulfilment of GSSP requirements has revealed that in some respects the Russian sections are better studied. The Kimmeridgian–Tithonian (Volgian) boundary transition is especially fully investigated at the Gorodischi section, which could be used as the GSSP for the Tithonian Stage and as a secondary stratotype section and point (SSSP) for the Volgian Stage.
... A single Re–Os date is available from ammonite-bearing marine sedimentary successions in the Lower Kimmeridgian (Selby, 2007). As a consequence, the Late Jurassic Time Scale derives mainly from the Pacific seafloor-spreading numerical model of the M-sequence magnetic polarity pattern and from limited recent cyclostratigraphic studies ( Ogg et al. 2010; Gradstein et al. 2012 ). Magnetostratigraphy can be calibrated with ammonite assemblage biochronology, which is mainly defined in northwestern †Author for correspondence: Pierre.Pellenard@u-bourgogne.fr ...
... However, provincialism in Boreal, sub-Boreal, sub- Mediterranean and Tethyan domains prevents unequivocal zonation correlation, especially for certain intervals, and hence introduces a temporal bias in the magnetostratigraphic model. Despite recent progress in reducing this bias (Ogg et al. 2010; Przybylski et al. 2010; Gradstein et al. 2012), the scarcity of interbedded volcanic units in ammonite-bearing marine successions hinders the accurate numerical calibration of the Late Jurassic Time Scale, even with the progress made in the GTS2012, including improved numerical ages for stage boundaries, obtained by selecting only single-zircon U–Pb ages, recalculating 40 Ar– 39 Ar dates and more precise magnetostratigraphy and cyclostratigraphy. Therefore, to obtain radiometrically calibrated tie-points for the Late Jurassic, biostratigraphically constrained volcanic ash layers in Tethyan basins have been studied (Pellenard et al. 2003; Pellenard & Deconinck, 2006). ...
... As a consequence, Middle–Upper Jurassic biozone duration and stage boundary ages are mainly estimated from secondary radiometric guides, indirect methods and mathematical interpolations. These approaches combine a magnetostratigraphic age model based on the cycle-scaling of the M-sequence spreading rate model correlated to the magnetostratigraphy of outcrops (Ogg et al. 2010; Przybylski et al. 2010; Gradstein et al. 2012 ) and cycle-derived durations of ammonite zones from cyclostratigraphy (Boulila et al. 2008Boulila et al. , 2010 Ogg, Ogg & Gradstein, 2008; Huang, Hesselbo & Hinnov, 2010; Gradstein et al. 2012 ). Cyclostratigraphy from SE France has considerably modified ammonite biozone durations. ...
Eight volcanic ash layers, linked to large explosive events caused by subduction-related volcanism from the Vardar Ocean back-arc, interbedded with marine limestones and cherts, have been identified in the Rosso Ammonitico Veronese Formation (northeastern Italy). The thickest ash layer, attributed to the Gregoryceras transversarium ammonite Biozone (Oxfordian Stage), yields a precise and reliable 40Ar–39Ar date of 156.1 ± 0.89 Ma, which is in better agreement with GTS2004 boundaries than with the current GTS2012. This first biostratigraphically well-constrained Oxfordian date is proposed as a new radiometric tie-point to improve the Geologic Time Scale for the Late Jurassic, where ammonite-calibrated radiometric dates are particularly scarce.
... A single Re-Os date is available from ammonite-bearing marine sedimentary successions in the Lower Kimmeridgian (Selby, 2007). As a consequence, the Late Jurassic Time Scale derives mainly from the Pacific seafloor-spreading numerical model of the M-sequence magnetic polarity pattern and from limited recent cyclostratigraphic studies Ogg et al. 2010;Gradstein et al. 2012). Magnetostratigraphy can be calibrated with ammonite assemblage biochronology, which is mainly defined in northwestern †Author for correspondence: Pierre.Pellenard@u-bourgogne.fr ...
... We restrict ourselves to investigating the coarsest (>30 Myr) timescale variations, as these are most readily explained in terms of mantle convection processes. e earliest parts of the marine magnetic anomaly record (Fig. 1a) cannot be straightforwardly interpreted in terms of a reversal sequence, but continental magnetostratigraphic studies suggest that anomalies back to at least 160 Myr ago are indeed associated with reversals 33,34 . Two periods in the last 200 Myr seem to represent examples of the most extreme geomagnetic behaviour observed so far ( Fig. 1): the Middle-Late Jurassic (around 150-170 Myr ago) when reversal frequency peaked 29,33 , possibly in excess of 12 Myr -1 ; and the Cretaceous Normal Superchron (CNS; 84-121 Myr ago) when the eld was almost exclusively of single polarity for a period spanning nearly 40 Myr 35,36 . ...
The Earth's internal magnetic field varies on timescales of months to billions of years. The field is generated by convection in the liquid outer core, which in turn is influenced by the heat flowing from the core into the base of the overlying mantle. Much of the magnetic field's variation is thought to be stochastic, but over very long timescales, this variability may be related to changes in heat flow associated with mantle convection processes. Over the past 500 Myr, correlations between palaeomagnetic behaviour and surface processes were particularly striking during the middle to late Mesozoic era, beginning about 180 Myr ago. Simulations of the geodynamo suggest that transitions from periods of rapid polarity reversals to periods of prolonged stability - such as occurred between the Middle Jurassic and Middle Cretaceous periods - may have been triggered by a decrease in core-mantle boundary heat flow either globally or in equatorial regions. This decrease in heat flow could have been linked to reduced mantle-plume-head production at the core-mantle boundary, an episode of true polar wander, or a combination of the two.
... We restrict ourselves to investigating the coarsest (>30 Myr) timescale variations, as these are most readily explained in terms of mantle convection processes. e earliest parts of the marine magnetic anomaly record (Fig. 1a) cannot be straightforwardly interpreted in terms of a reversal sequence, but continental magnetostratigraphic studies suggest that anomalies back to at least 160 Myr ago are indeed associated with reversals 33,34 . Two periods in the last 200 Myr seem to represent examples of the most extreme geomagnetic behaviour observed so far ( Fig. 1): the Middle-Late Jurassic (around 150-170 Myr ago) when reversal frequency peaked 29,33 , possibly in excess of 12 Myr -1 ; and the Cretaceous Normal Superchron (CNS; 84-121 Myr ago) when the eld was almost exclusively of single polarity for a period spanning nearly 40 Myr 35,36 . ...
The geomagnetic field is generated by the convection of molten metal in
the Earth's outer core that is itself controlled by heat flowing across
the core-mantle boundary. It has long been suspected that
palaeomagnetically-observed variations in geomagnetic behaviour
occurring over tens to hundreds of millions of years result from changes
in core-mantle boundary heat flow forced by dynamical processes
occurring at the base of the mantle. Furthermore, the last few decades
have seen numerous claims of causal relations between the palaeomagnetic
record and surface events inferred from the geological record.
Essentially, these attempt to constrain elements of mantle convection
(sinking slabs, rising plumes, and the resulting true polar wander)
using signals ultimately derived from the mantle's bounding layers: the
outer core and crust. The state-of-the-art in seismology, geodynamics,
and the numerical simulation of both mantle convection and the geodynamo
provides qualitative support for the viability of this approach and even
for certain specific linkages (some to be newly outlined here).
Quantitative testing and refinement of such overarching hypotheses will
require advances in a wide range of disciplines, but may ultimately
produce a fundamental contribution to our understanding of the dynamics
of the Earth's interior.
The Jurassic oceanic crust is the oldest existing oceanic crust on earth, and although distributed sparsely, carries essential information about the earth’s evolution. The area around the Pigafetta Basin in the west Pacific Ocean (also known as the Jurassic Quiet Zone, JQZ) is one of a few areas where the Jurassic oceanic crust is present. This study takes full advantage of high-resolution multichannel seismic reflection profiles in combination with bathymetry, magnetic, and gravity data from the JQZ to examine the structure, deformation, and morphology of the Jurassic oceanic crust. Our results show the following insights: 1) The Moho lies at 2–3s in two-way travel time beneath the seafloor with the segmented feature. The gaps between the Moho segments well correspond to the seamounts on the seafloor, suggesting the upward migration of magma from the mantle has interrupted the pre-existing Moho. 2) The oceanic crust is predominantly deformed by crustal-scale thrust faults, normal faults cutting through the top of basement, and vertical seismic disturbance zones in association with migration of thermal fluids. The thrust faults are locally found and interpreted as the results of tectonic inversion. 3) Seafloor morphology in the JQZ is characterized by fault scarps, fold scarps, seamounts, and small hills, indicating the occurrence of active faults. 4) The oceanic crust in the JQZ and East Pacific Rise has many structural and geometrical variations, such as the thickness of sediments, seafloor topography, basement morphology, fault size and type.
