Research Article

On impact and volcanism across the Cretaceous-Paleogene boundary

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Science  17 Jan 2020:
Vol. 367, Issue 6475, pp. 266-272
DOI: 10.1126/science.aay5055
  • Fig. 1 Global temperature change across the K/Pg boundary.

    New and existing empirical temperature records from marine sediments (foraminiferal δ18O, foraminiferal Mg/Ca, and TEX86 measurements), shallow marine carbonates (clumped isotopes of mollusk carbonate), and terrestrial proxies (leaf margin analysis, biomarkers, clumped isotopes of mollusk carbonate) were aligned to a common age model (tables S2 and S3) and normalized to the latest Cretaceous temperature within each record. A 60-point fast Fourier transform (FFT) smoother of global temperature change is shown in dark red. Data are provided in tables S4 to S12. Some outlying data points do not fall within plot bounds but can be seen in figs. S1 to S16. Pl., planktonic; Ben., benthic; Foram., foraminiferal.

  • Fig. 2 K/Pg boundary dynamics at the best-resolved deep-sea sites globally: Shatsky Rise, Walvis Ridge, and J-Anomaly Ridge.

    High-resolution (A) carbon and (B) oxygen isotope dynamics in benthic foraminifera (transparent shaded areas) and bulk carbonate (discrete points) and (C) sediment composition (weight % coarse fraction) at Shatsky Rise (blue), Walvis Ridge (gray), and J-Anomaly Ridge (red). (D) Global records of nannofossil (green) and foraminifera [blue, from (61)] species richness (40). The major interval of Deccan Trap emplacement (estimated 93% of volume) is indicated at left by the black bar (8). Ocean drilling sites are listed by number. VPDB, Vienna Pee Dee belemnite; calc. nanno., calcareous nannofossil; plankt. foram., planktonic foraminifera; Sp. rich., species richness.

  • Fig. 3 Global temperature change across the K/Pg boundary compared to modeled temperature change in five scenarios for Deccan Trap outgassing.

    Outgassing scenarios include (A) case 1 (leading), with most outgassing before impact; (B) case 2 (50:50), with 50% outgassing before impact and 50% after impact; (C) case 3 (punctuated), with four pulses including a major event just before the K/Pg boundary; (D) case 4 (lagging), with most outgassing after impact; and (E) case 5 (spanning), with continuous outgassing throughout magnetochron C29r (Table 1). Each model scenario is represented by four lines (bounding a shaded region) delineating different combinations of climate sensitivity and volcanic outgassing: high degassing (9545 Gt C and 8500 Gt S) and 3°C per CO2 doubling (thick gray line); high degassing and 4°C per doubling (thick black line); low degassing (4090 Gt C and 3200 Gt S) and 3°C per doubling (thin gray line); and low degassing and 2°C per doubling (thin black line). A 60-point FFT smoother of global temperature change (red line; see Fig. 1) is provided for comparison. The timing of Deccan outgassing assumed in each scenario is indicated by the bars at left in each panel, with the shading intensity of the bar denoting the proportion of outgassing in that interval.

  • Fig. 4 Surface ocean δ13C change across the late Maastrichtian warming compared to modeled δ13C change in five scenarios for Deccan Trap outgassing.

    (A to E) Bulk carbonate ∆δ13C (20-point FFT smoother of data from Site U1403 and Site 1262) is shown against surface ocean δ13C for end-member outgassing and climate sensitivity scenarios (gray shaded area) for each case, as detailed in Fig. 3. In each case, carbonate carbon isotopes are expressed as ∆δ13C, relative to the late Maastrichtian high of 3.03‰ at 0.432 Myr before the onset of the CO2 release (see also figs. S36 and S37).

  • Fig. 5 Late Cretaceous warming and early Paleocene record of environmental and biotic change at IODP Site U1403, J-Anomaly Ridge, Newfoundland.

    A negative carbon isotope anomaly (A) coincides with late Cretaceous warming in δ18O (B) and osmium isotope evidence for volcanism (A) at IODP Site U1403. The collapse in surface ocean δ13C values (A) coincides with an iridium anomaly (B) and step change in fish tooth accumulation (C). The earliest Paleocene δ18O values of bulk carbonate appear to be strongly influenced by vital effects driven by rapid turnover in the dominant calcareous nannofossil taxa (D) in sites globally (figs. S18, S34, and S35). Data are in tables S12, S16, S17, and S29. AR, accumulation rate; Frag, fragment; ppb, parts per billion; sed, sediment.

  • Table 1 Model parameters for five focal Deccan outgassing scenarios tested in LOSCAR.

    Δ denotes change in value (reduction or increase). pre, before impact; post, after impact; Frac. int.-depth Corg remin., fraction of intermediate depth organic carbon remineralization.

    Case 1: LeadingCase 2: 50:50Case 3: PunctuatedCase 4: LaggingCase 5: Spanning
    Volcanic outgassing
    Pulse 1 (pre):
    Volume
    87% of total
    high: 8305 Gt C,
    7395 Gt S
    low: 3559 Gt C,
    2784 Gt S
    50% of total
    high: 4773 Gt C,
    4250 Gt S
    low: 2045 Gt C,
    1600 Gt S
    20% of total
    high: 1909 Gt C,
    1700 Gt S
    low: 818 Gt C,
    640 Gt S
    13% of total
    high: 1241 Gt C,
    1105 Gt S
    low: 532 Gt C,
    416 Gt S
    100% of total
    high: 9545 Gt C,
    8500 Gt S
    low: 4091 Gt C,
    3200 Gt S
    TimingStarts: −358 kyr
    Ends: −218 kyr
    Starts: −358 kyr
    Ends: −218 kyr
    Starts: −290 kyr
    Ends: −110 kyr
    Starts: −358 kyr
    Ends: −218 kyr
    Starts: −358 kyr
    Ends: 355 kyr
    Pulse 2 (pre):
    Volume
    35% of total
    high: 3340 Gt C,
    2975 Gt S
    low: 1431 Gt C,
    1120 Gt S
    Timing Starts: −60 kyr
    Ends: −20 kyr
    Pulse 1 (post):
    Volume
    13% of total
    high: 1241 Gt C,
    1105 Gt S
    low: 532 Gt C,
    416 Gt S
    50% of total
    high: 4773 Gt C,
    4250 Gt S
    low: 2045 Gt C,
    1600 Gt S
    35% of total
    high: 3340 Gt C,
    2975 Gt S
    low: 1431 Gt C,
    1120 Gt S
    87% of total
    high: 8305 Gt C,
    7395 Gt S
    low: 3559 Gt C,
    2784 Gt S
    TimingStarts: 0 kyr
    Ends: 355 kyr
    Starts: 0 kyr
    Ends: 355 kyr
    Starts: 80 kyr
    Ends: 170 kyr
    Starts: 0 kyr
    Ends: 355 kyr
    Pulse 2 (post):
    Volume
    10% of total
    high: 955 Gt C,
    850 Gt S
    low: 409 Gt C,
    320 Gt S
    Timing Starts: 390 kyr
    Ends: 430 kyr
    Impact outgassing
    Volume100% of total
    115 Gt C, 325 Gt S
    100% of total
    115 Gt C, 325 Gt S
    100% of total
    115 Gt C, 325 Gt S
    100% of total
    115 Gt C, 325 Gt S
    100% of total
    115 Gt C, 325 Gt S
    TimingStarts: 0 kyr
    Ends: 1 kyr
    Starts: 0 kyr
    Ends: 1 kyr
    Starts: 0 kyr
    Ends: 1 kyr
    Starts: 0 kyr
    Ends: 1 kyr
    Starts: 0 kyr
    Ends: 1 kyr
    Biotic change
    Organic export
    flux Δ
    50% reduction50% reduction50% reduction50% reduction50% reduction
    CaCO3 export
    flux Δ
    42.5% reduction42.5% reduction42.5% reduction42.5% reduction42.5% reduction
    Frac. int.-depth
    Corg remin. Δ
    22% increase22% increase22% increase22% increase22% increase
    TimingStarts: 0 kyr
    immediately tapers
    Ends: 1770 kyr
    Starts: 0 kyr
    immediately tapers
    Ends: 1770 kyr
    Starts: 0 kyr
    immediately tapers
    Ends: 1770 kyr
    Starts: 0 kyr
    immediately tapers
    Ends: 1770 kyr
    Starts: 0 kyr
    immediately tapers
    Ends: 1770 kyr
  • Table 2 Mean absolute error (MAE) and mean minimum absolute error (MMAE) of cases relative to the interpolated global temperature record.

    MMAE was calculated for each case by determining whether the empirical data fell outside of the temperature range bounded by the high- and low-outgassing scenarios, given a climate sensitivity of 3°C per CO2 doubling, and, if so, by how much. MAEs were also calculated for each outgassing volume and climate sensitivity shown in Fig. 3. MMAEs and MAEs were calculated on a 20-kyr interpolated time step from 360 kyr before and 600 kyr after the K/Pg. Case 2 consistently has the lowest MAEs, and cases 1 and 2 have the lowest MMAEs. volc., volcanic outgassing; doub., doubling.

    MMAEMAE (high volc.,
    3°C per CO2 doub.)
    MAE (high volc.,
    4°C per CO2 doub.)
    MAE (low volc.,
    3°C per CO2 doub.)
    MAE (low volc.,
    2°C per CO2 doub.)
    Case 10.250.460.650.500.58
    Case 20.210.350.430.480.58
    Case 30.450.590.650.580.64
    Case 40.450.610.690.560.63
    Case 50.290.400.440.530.61

Supplementary Materials

  • On impact and volcanism across the Cretaceous-Paleogene bound

    Pincelli M. Hull, André Bornemann, Donald E. Penman, Michael J. Henehan, Richard D. Norris, Paul A. Wilson, Peter Blum, Laia Alegret, Sietske J. Batenburg, Paul R. Bown, Timothy J. Bralower, Cecile Cournede, Alexander Deutsch, Barbara Donner, Oliver Friedrich, Sofie Jehle, Hojung Kim, Dick Kroon, Peter C. Lippert, Dominik Loroch, Iris Moebius, Kazuyoshi Moriya, Daniel J. Peppe, Gregory E. Ravizza, Ursula Röhl, Jonathan D. Schueth, Julio Sepúlveda, Philip F. Sexton, Elizabeth C. Sibert, Kasia K. Śliwińska, Roger E. Summons, Ellen Thomas, Thomas Westerhold, Jessica H. Whiteside, Tatsuhiko Yamaguchi, James C. Zachos

    Materials/Methods, Supplementary Text, Tables, Figures, and/or References

    Download Supplement
    • Materials and Methods
    • Supplementary Text
    • Figs. S1 to S44
    • Tables S1 and S2
    • Captions for Tables S3 to S31
    • References
    Tables S1 to S31

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