Research ArticleEARTH SCIENCE

High-precision geochronology confirms voluminous magmatism before, during, and after Earth’s most severe extinction

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Science Advances  28 Aug 2015:
Vol. 1, no. 7, e1500470
DOI: 10.1126/sciadv.1500470
  • Fig. 1 Generalized map of the current extent of Siberian Traps LIP rocks.

    Overlain on the map are sample names and locations, which are keyed by color to rock type. Base map and outcrop extent modified from (9). Stratigraphic sections for the Noril’sk and Maymecha-Kotuy sections showing lava stratigraphy and sample location. Stratigraphy modified from (11).

  • Fig. 2 Single-grain and weighted mean 206Pb/238U dates for Siberian Traps LIP sills, lavas, and pyroclastic rocks.

    The population of single-grain analyses from which the weighted mean date is calculated is shown for each dated sample. The height of each single-grain date is proportional to the 2σ analytical uncertainty on that point. The horizontal rectangle through each population represents the 2σ uncertainty on the weighted mean, which itself is represented by a thin horizontal line. Translucent single-grain analyses are not included in the weighted mean calculations. The horizontal gray rectangle and dashed red line running the length of the figure represent the mass extinction interval and calculated date of the paleontologically defined P-T boundary, respectively (4). Samples are color-keyed to match Fig. 1. Raw data can be found in table S2.

  • Fig. 3 Stratigraphy, geochronology, and magnetic polarity for Siberian Traps LIP rocks and the Permian-Triassic GSSP at Meishan, China.

    Placement of the Permian-Triassic boundary on the lava stratigraphy is based on magnetic polarity, geochemistry, and geochronology. Polarity for the Noril’sk and Maymecha-Kotuy sections from (3032). Paleopolarity for the GSSP section from (33). The Permian-Triassic boundary shown is defined by the first appearance datum of the conodont Hindeodus parvus and is shown as the solid red line. Placement of the P-T boundary from (4).

  • Fig. 4 Timeline through the late Permian and early Triassic showing the record of Siberian Traps LIP magmatism, the end-Permian mass extinction interval, and the carbonate carbon isotopic record.

    Age model for the mass extinction from (4). Carbon isotope data from (4, 49). Carbon isotope record is scaled to time using dates from (4) and is segmented into Intervals (1 to 5) based on the placement of bracketing ash bed dates and record topology. Shading used for the intrusive rock timeline indicates that magma flux per unit time is uncertain between dated samples.

  • Table 1 Weighted mean 206Pb/238U dates for Siberian Traps LIP rocks.

    All dates are corrected for initial Th disequilibrium. Complete analytical details can be found in tables S1 and S2.

    Sample no.Location/nameMineralDate (Ma)2σ (x/y/z)*MSWDn
    Sill
      A10-23-1Bratsk/PadunskiiZircon251.6810.063/0.091/0.281.28
      A10-23-2Bratsk/PadunskiiZircon251.5390.056/0.086/0.281.211
      A10-23-3Bratsk/PadunskiiZircon251.460.051/0.083/0.28112
      194/35/860Nepa/lower sill/Scholokhovskoie pipeZircon251.3540.088/0.11/0.290.44
      SHl-3085Nepa/Scholokhovskoie pipeZircon251.5010.071/0.097/0.290.3410
      LT10-1-1Lower TungusskayaZircon251.7860.054/0.085/0.280.698
      LT10-2-2Lower TunguskaZircon251.7950.070/0.096/0.291.314
      NT12-5-4Lower TunguskaZircon251.740.18/0.19/0.330.652
      S68-700Bratsk/Oktyabroskoe depositZircon251.5090.044/0.079/0.281.413
      O-6832Bratsk/Oktyabroskoe depositZircon251.5040.059/0.088/0.280.368
      KZ1818-1691Noril’sk/KharaelakhZircon251.710.14/0.16/0.310.133
      KZ1799-1195Noril’sk/TalnakhZircon251.8010.088/0.11/0.290.4510
      R06-05Noril’sk/ChernogorskyZircon251.660.064/0.092/0.280.79
      G22-105-2Noril’sk/Noril’sk 1Zircon251.640.10/0.12/0.300.4811
      G22-63-5Noril’sk/Noril’sk 1Zircon251.9070.067/0.094/0.290.72
      G22-65-0Noril’sk/Noril’sk 1Zircon251.8130.065/0.092/0.2815
      N12-3-2DaldykanskyZircon251.3760.050/0.082/0.281.17
    Lava
      K08-14-3Maymecha-KotuyPerov252.200.12/0.16/0.311.115
      K09-6-1Maymecha-KotuyPerov252.270.11/0.15/0.311.112
    Welded tuff
      M09-11-1Maymecha-KotuyZircon251.9010.061/0.089/0.281.621
      M09-12-1Maymecha-KotuyZircon251.4830.088/0.11/0.291.17
    Pyroclastic breccia
      A10-13-3Angara riverZircon256.560.46/0.51/0.58n/a1
      SG2610.4Noril’skZircon255.580.38/0.43/0.51n/a1
    End-Permian mass extinction (4)
      Onset of extinctionMeishan, China Bed 25Zircon251.9410.037/0.281.316
      Cessation of extinctionMeishan, China Bed 28Zircon251.880.031/0.280.7613

    *Uncertainties associated with weighted mean 206Pb/238U dates are reported as ±x/y/z, where x are the analytical (internal) uncertainties and y and z include the systematic uncertainties associated with tracer calibration (0.03%) and 238U decay constant (0.05%), respectively. If calculated dates are to be compared with other U-Pb laboratories not using the EARTHTIME tracer, then ±y should be used. If compared to other chronometers such as Ar-Ar or astrochronology, then ±z should be used.

    Supplementary Materials

    • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/1/7/e1500470/DC1

      Fig. S1. Perovskite and clinopyroxene isochrons for sample K08-14-3.

      Fig. S2. Perovskite and clinopyroxene isochrons for sample K09-6-1.

      Fig. S3. Perovskite and clinopyroxene isochrons for sample K09-6-2.

      Fig. S4. Nickel concentration in the Noril’sk lava stratigraphy.

      Table S1. LA-ICPMS zircon data for Siberian Traps LIP pyroclastic rocks and lavas.

      Table S2. Zircon and perovskite U/Pb isotopic data and calculated dates.

    • Supplementary Materials

      This PDF file includes:

      • Fig. S1. Perovskite and clinopyroxene isochrons for sample K08-14-3.
      • Fig. S2. Perovskite and clinopyroxene isochrons for sample K09-6-1.
      • Fig. S3. Perovskite and clinopyroxene isochrons for sample K09-6-2.
      • Fig. S4. Nickel concentration in the Noril’sk lava stratigraphy.
      • Table S1. LA-ICPMS zircon data for Siberian Traps LIP pyroclastic rocks and lavas.
      • Legend for table S2

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      Other Supplementary Material for this manuscript includes the following:

      • Table S2 (Microsoft Excel format). Zircon and perovskite U/Pb isotopic data and calculated dates.

      Files in this Data Supplement:

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