Table 2.

Calibration, sampling, and age–depth model information for sites in Fig. 1, group 3a, with results of attempts to replicate proposed depths of YDB-age deposits

SiteOriginally reported 14C calibration*Radiometric ages from ∼same column as samples for impact markers?Regression method used in original YDB depth calculationDepth of proposed YDB layer originally reported (midpoint)Recalculated predicted depth of YDB-age depositsDepth difference (column 6 minus column 5)
Abu HureyraIntCal04No, depth scale arbitraryLinear284.29 masl284.63 masl34 cm
284.70 masl284.63 masl−7 cm
Arlington CanyonIntCal09YesLinear500.50 cmbs441.14 cmbs−59.36 cm
Barber Creekn/a – OSLYesSecond-order polynomial100 cmbs109.47 cmbs9.47 cm
Blackvillen/a – OSLYesLinear183 cmbs174.67 cmbs−8.33 cm
Blackwater DrawIntCal04No, depth scale arbitraryLogarithmic1,237.56 masl1,237.59 masl3 cm
Kimbel BayIntCal09YesLogarithmic358 cmbs353.56 cmbs−4.44 cm
Lake CuitzeoIntCal04YesFifth-order polynomial282 cmbs259.33 cmbs−22.67 cm
Melrosen/a – OSLYesLinear21 cmbs22.02 cmbs1.02 cm
Murray SpringsIntCal04No, depth scale arbitrarySecond-order polynomial246 cmbs246.88 cmbs0.88 cm
TalegaIntCal09YesSecond-order polynomial14.85–15.15 mbs (15 mbs)−33.05 mbs−48 m
Toppern/a – OSLNo, depth scale arbitrarySecond-order polynomial57.5–62.5 cmbs (60 cmbs)58.63 cmbs−1.37 cm
  • * The date of 12,900 cal B.P. is used for calculation purposes in column 6 for those sites with radiocarbon ages originally calibrated using IntCal04 or where only OSL dates are available but YDB was estimated as 12,900 cal B.P. (e.g., Melrose); for all other sites, 12,800 cal B.P. is used for calculation purposes in column 6.

  • Yes indicates that 14C and/or OSL samples come from the same vertical column as was sampled for impact markers, or from sufficiently close by that they are on the same scale of absolute depth. No indicates that 14C and OSL samples are from parts of the site other than where samples were collected for impact markers and are not on the same absolute depth scale.

  • Two different depths are provided for the supposed YDB layer at Abu Hureyra: as layer 445 at depth of 284.70 masl (ref. 3, SI p. 2) and 284.29 masl (ref. 10, SI table S1). Our recalculated predicted depth of YDB-age deposits is compared with each of these depths.