NEW GEOCHRONOLOGICAL DATA AND AGE MODEL APPROACHES FOR THE LATE JURASSIC THROUGH EARLY CRETACEOUS GEOLOGIC TIME SCALE

2018 ◽  
Author(s):  
Mark D. Schmitz ◽  
Keyword(s):  
Early Cretaceous ◽  
Time Scale ◽  
Late Jurassic ◽  
Geochronological Data ◽  
Geologic Time ◽  
Geologic Time Scale ◽  
Age Model

The first 40Ar–39Ar date from Oxfordian ammonite-calibrated volcanic layers (bentonites) as a tie-point for the Late Jurassic

2013 ◽  
Vol 150 (6) ◽  
pp. 1136-1142 ◽  
Author(s):  
P. PELLENARD ◽  
S. NOMADE ◽  
L. MARTIRE ◽  
F. DE OLIVEIRA RAMALHO ◽  
F. MONNA ◽  
...  
Keyword(s):  
Time Scale ◽  
Late Jurassic ◽  
Volcanic Ash ◽  
Geologic Time ◽  
Ash Layer ◽  
Northeastern Italy ◽  
Geologic Time Scale ◽  
Back Arc ◽  
Radiometric Dates ◽  
Explosive Events

AbstractEight 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.

Assessing orbital vs. volcanic control on carbon cycle during the Early Cretaceous

2021 ◽  
Author(s):  
Mathieu Martinez ◽  
Beatriz Aguirre-Urreta ◽  
Marina Lescano ◽  
Guillaume Dera ◽  
Julieta Omarini ◽  
...  
Keyword(s):  
Carbon Isotope ◽  
Early Cretaceous ◽  
Time Scale ◽  
Environmental Changes ◽  
Large Igneous Province ◽  
Carbonate Production ◽  
Geologic Time ◽  
Lower Amplitude ◽  
Igneous Province ◽  
Geologic Time Scale

<p>The interval from the Valanginian to the Barremian stages (137–121 Ma; Early Cretaceous) is punctuated by several episodes of environmental changes, accompanied by shifts in weathering intensity on the continents and changes in the Tethyan neritic carbonate production. We synthetize here the astrochronology of two recent studies performed in the Neuquén basin, Vocontian Basin and Subbetic Domain (Aguirre-Urreta et al., 2019; Martinez et al., 2020), anchored to CA-ID-TIMS U-Pb ages, which conclusions have been included in the Geologic Time Scale 2020 (Gale et al, in press). We applied this time scale to a compilation of carbon-isotope ratio from belemnites and proxies of detrital supply in the Tethyan area (Vocontian Basin and Subbetic Domain). From this compilation, we show that the episodes of environmental changes are paced by a 2.4-Myr cycle and, with a lower amplitude, a 1.2-Myr cycle. In addition, the new time scale shows the synchronicity between the Weissert Event and the Parana-Etendeka Large Igneous Province. In the series of carbon-isotope ratios measured on belemnite rostra, the amplitude of the 2.4-Myr cycle is twice higher during the Valanginian than in the Late Barremian and three times higher than in the Hauterivian and Early Barremian, suggesting that the activity of the Parana-Etendeka Large Igneous Province amplified the initial orbital forcing to trigger the environmental changes observed during the Mid-Valanginian.</p><p>Reference:</p><p>Aguirre-Urreta, B., Martinez, M., Schmitz, M., Lescano, M., Omarini, J., Tunik, M., Kuhnert, H., Concheyro, A., Rawson, P.F., Ramos, V.A., Reboulet, S., Noclin, N., Frederichs, T., Nickl, A.-L., Pälike, H., 2019. Interhemispheric radio-astrochronological calibration of the time scales from the Andean and the Tethyan areas in the Valanginian–Hauterivian (Early Cretaceous). Gondwana Research 70, 104-132. https://doi.org/10.1016/j.gr.2019.01.006.</p><p>Gale, A.S., Mutterlose, J., Batenburg, S., in press. Chapter 27: The Cretaceous Period, in: Gradstein, F.M., Ogg, J.G., Schmitz, M.D., Ogg, G.M. (Eds.) Geologic Time Scale 2020. Elsevier BV, Amsterdam, The Netherlands, pp. 1023–1086.</p><p>Martinez, M., Aguado, R., Company, M., Sandoval, J., O’Dogherty, L., 2020. Integrated astrochronology of the Barremian Stage (Early Cretaceous) and its biostratigraphic subdivisions. Global and Planetary Change 195, 103368. https://doi.org/10.1016/j.gloplacha.2020.103368.</p>

AGE MODEL FOR LATE JURASSIC THROUGH EARLY CRETACEOUS USED IN THE GEOLOGIC TIMESCALE 2012/2016 REFERENCE SCALES

2018 ◽  
Author(s):  
James G. Ogg ◽  
◽  
Chunju Huang ◽  
Chunju Huang ◽  
Linda A. Hinnov ◽  
...  
Keyword(s):  
Early Cretaceous ◽  
Late Jurassic ◽  
Age Model

A Geologic Time Scale 1989. W. B. Harland

1991 ◽  
Vol 99 (5) ◽  
pp. 786-786
Author(s):  
John J. Flynn
Keyword(s):  
Time Scale ◽  
Geologic Time ◽  
Geologic Time Scale

Magnetostratigraphy of U-Pb–dated boreholes in Svalbard, Norway, implies that magnetochron M0r (a proposed Barremian-Aptian boundary marker) begins at 121.2 ± 0.4 Ma

Geology ◽  
2021 ◽  
Author(s):  
Yang Zhang ◽  
James G. Ogg ◽  
Daniel Minguez ◽  
Mark W. Hounslow ◽  
Snorre Olaussen ◽  
...  
Keyword(s):  
Spreading Rate ◽  
Magnetic Polarity ◽  
Stratigraphic Correlation ◽  
Geologic Time ◽  
Oceanic Spreading ◽  
M Sequence ◽  
Geologic Time Scale ◽  
Age Model ◽  
Oceanic Basalts ◽  
Radioisotopic Dating

The age of the beginning of magnetic polarity Chron M0r, a proposed marker for the base of the Aptian Stage, is disputed due to a divergence of published radioisotopic dates and ambiguities in stratigraphic correlation of sections. Our magnetostratigraphy of core DH1 from Svalbard, Norway, calibrates a bentonite bed, dated by U-Pb methods to 123.1 ± 0.3 Ma, to the uppermost part of magnetozone M1r, which is ~1.9 m.y. before the beginning of Chron M0r. This is the first direct calibration of any high-precision radioisotopic date to a polarity chron of the M sequence. The interpolated age of 121.2 ± 0.4 Ma for the beginning of Chron M0r is younger by ~5 m.y. than its estimated age used in the Geologic Time Scale 2012, which had been extrapolated from radioisotopic dates on oceanic basalts and from Aptian cyclostratigraphy. The adjusted age model implies a commensurate faster average global oceanic spreading rate of ~12% during the Aptian–Santonian interval. Future radioisotopic dating and high-resolution cyclostratigraphy are needed to investigate where to expand the mid-Jurassic to earliest Cretaceous interval by the required ~4 m.y.

A geologic time scale

2013 ◽  
pp. 476-476
Author(s):  
Frank D. Stacey ◽  
Paul M. Davis
Keyword(s):  
Time Scale ◽  
Geologic Time ◽  
Geologic Time Scale

The times they are a-changin': Australian biozones, petroleum basins, and the international geologic time scale (GTS) 2012

2014 ◽  
Vol 54 (2) ◽  
pp. 473
Author(s):  
Tegan Smith ◽  
John Laurie ◽  
Lisa Hall ◽  
Robert Nicoll ◽  
Andrew Kelman ◽  
...  
Keyword(s):  
Time Scale ◽  
Age Dating ◽  
Burial History ◽  
Geologic Time ◽  
Petroleum Systems ◽  
Geologic Time Scale ◽  
History Of ◽  
And Migration ◽  
The Times ◽  
Hydrocarbon Expulsion

The international Geologic Time Scale (GTS) continually evolves due to refinements in age dating and the addition of more defined stages. The GTS 2012 has replaced GTS 2004 as the global standard timescale, resulting in changes to the age and duration of most chronological stages. These revisions have implications for interpreted ages and durations of sedimentary rocks in Australian basins, with ramifications for petroleum systems modelling. Accurate stratigraphic ages are required to reliably model the burial history of a basin, hence kerogen maturation and hydrocarbon expulsion and migration. When the resolution of the time scale is increased, models that utilise updated ages will better reflect the true basin history. The international GTS is largely built around northern hemisphere datasets. At APPEA 2009, Laurie et al. announced a program to tie Australian biozones to GTS 2004. Now, with the implementation of GTS 2012, these ties are being updated and refined, requiring a comprehensive review of the correlations between Australian and International biozonation schemes. The use of Geoscience Australia’s Timescales Database and a customised ‘Australian Datapack’ for the visualisation software package TimeScale Creator has greatly facilitated the transition from GTS 2004 to GTS 2012, as anticipated in the design of the program in 2009. Geoscience Australia’s basin biozonation and stratigraphy charts (e.g. Northern Carnarvon and Browse basins) are being reproduced to reflect the GTS 2012 and modified stratigraphic ages. Additionally, new charts are being added to the series, including a set of onshore basin charts, such as the Georgina and Canning basins.

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