Supplementary Materials for

Transcription

1 advances.sciencemag.org/cgi/content/full/4/5/eaar5040/dc1 Supplementary Materials for Deglaciation of the Pacific coastal corridor directly preceded the human colonization of the Americas Alia J. Lesnek, Jason P. Briner, Charlotte Lindqvist, James F. Baichtal, Timothy H. Heaton This PDF file includes: Published 30 May 2018, Sci. Adv. 4, eaar5040 (2018) DOI: /sciadv.aar5040 fig. S1. Map of southeastern Alaska with labeled islands. fig. S2. Representative boulder and bedrock samples collected for 10 Be dating. fig. S3. Normal kernel density estimates of 10 Be ages. fig. S4. Fossilized mammal bone 14 C ages from caves in southeastern Alaska. fig. S5. Box-and-whisker plot of fossilized cave bone δ 13 C values from Prince of Wales Island. fig. S6. Sensitivity testing of the fossilized cave bone 14 C age calibration. fig. S7. Fossilized cave bone δ 13 C values and marine carbon percentages through time. table S1. 10 Be sample information. table S2. 10 Be ages calculated with alternative production rates and scaling schemes. table S3. Fossilized cave bone sample information used for 14 C calibration. Reference (66)

2 fig. S1. Map of southeastern Alaska with labeled islands. Shuká Káa on Prince of Wales Island is denoted by the orange star.

3 fig. S2. Representative boulder and bedrock samples collected for 10 Be dating. (A- B) Bedrock samples from Dall Island. (C) Perched boulder from Suemez Island. (D) Bedrock sample from the abraded surface of a rôche moutonée at Suemez Island. (E-F) Perched boulders from a cirque on Baker Island. (G) Bedrock sample from Warren Island. The old apparent 10 Be age of this sample is due to cosmogenic nuclide inheritance from previous exposure. (H) Perched boulder sample from Warren Island.

4 fig. S3. Normal kernel density estimates of 10 Be ages. In both panels, individual 10 Be ages are represented by the gray lines and the thicker black line represents the summed probability distribution of the entire 10 Be age population. (A) 10 Be ages from a cirque on Baker Island. Average excludes one outlier from a bedrock surface (15SEAK- 11; 17.0 ± 0.7 ka) that is >3 SD older than the remaining three 10 Be ages. (B) 10 Be ages from perched boulders and bedrock at Dall, Suemez, and Warren Islands. Average age excludes one outlier from a bedrock surface (17SEAK-12; 24.8 ± 1.0 ka) that is >3 SD older than the remaining nine 10 Be ages.

5 Cal ka BP fig. S4. Fossilized mammal bone 14 C ages from caves in southeastern Alaska. (A) Summed probability distribution of all ages. Dark green line = Shuká Káa; light green line = all other caves. (B) Fossilized mammal bones by species. Dots represent the mean of the total range of each calibrated 14 C age. Vertical gray bar denotes the timing of maximum CIS extent in southeastern Alaska.

6 fig. S5. Box-and-whisker plot of fossilized cave bone δ 13 C values from Prince of Wales Island. Fossils are grouped by species. White boxes show the Q1-Q3 interquartile range, and the horizontal black line in each box denotes the median. Black circles represent the average δ 13 C value for each species, and white circles denote outliers which have δ 13 C values exceeding 1.5 times the Q1-Q3 interquartile range from the median. Blue shading shows the divisions between various percentages of marine carbon used for the 14 C age calibration.

7 20.17 ± 0.59 to ± 1.20 cal ka BP ± 0.60 to ± 1.29 cal ka BP ± 0.59 to 17.1 ± 1.23 cal ka BP Cal ka BP fig. S6. Sensitivity testing of the fossilized cave bone 14 C age calibration. Under multiple calibration schemes, a hiatus in fossil 14 C ages (blue arrow) appears from ~20-17 ka.

8 Age (cal ka BP) fig. S7. Fossilized cave bone δ 13 C values and marine carbon percentages through time. Blue dots = 100% marine carbon; teal dots = 50% marine; green dots = 0% marine. Hiatus in fossil ages from ~20-17 ka, which is interpreted as CIS cover of the Alexander Archipelago, is indicated by the gray bar.

9 table S1. 10 Be sample information.

10 table S2. 10 Be ages calculated with alternative production rates and scaling schemes.

11 table S3. Fossilized cave bone sample information used for 14 C calibration.

12 table S3, continued

13 table S3, continued

14 table S3, continued

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