Matthew R. Bennett David Bustos Jeffrey S. Pigati Kathleen B. Springer Thomas M. Urban Vance T. Holliday Sally C. Reynolds Marcin Budka Jeffrey S. Honke Adam M. Hudson Brendan Fenerty Clare Connelly Patrick J. Martinez Vincent L. Santucci Daniel Odess 20210923 CSV FILES Denver CO U.S. GEOLOGICAL SURVEY https://doi.org/10.5066/P9ABZEM9 Matthew R. Bennett David Bustos Jeffrey S. Pigati Kathleen B. Springer Thomas M. Urban Vance T. Holliday Sally C. Reynolds Marcin Budka Jeffrey S. Honke Adam M. Hudson Brendan Fenerty Clare Connelly Patrick J. Martinez Vincent L. Santucci Daniel Odess 20210924 publication Science vol. 373, issue 6562 n/a American Association for the Advancement of Science (AAAS) ppg. 1528-1531 https://doi.org/10.1126/science.abg7586 Archaeologists and researchers in allied fields have long sought to understand human colonization of North America. When, how, and from where did people migrate, and what were the consequences of their arrival for the established fauna and landscape are enduring questions. Here, we present evidence from excavated surfaces of in situ human footprints from White Sands National Park (New Mexico, USA), where multiple human footprints are stratigraphically constrained and bracketed by seed layers that yield calibrated 14C ages between ~23 and 21 ka. These findings confirm the presence of humans in North America during the Last Glacial Maximum, adding evidence to the antiquity of human colonization of the Americas and providing a temporal range extension for the coexistence of early inhabitants and Pleistocene megafauna. These data were used to determine when early humans were present in what is now White Sands National Park, New Mexico. Entity_and_Attribute_Detail_Citation: 0_Data_Dictionary_WHSA_trackway_study.csv 2018 2021 2021 Complete NONE PLANNED -106.4500 -106.2000 32.9500 32.8000 USGS Thesaurus, USGS Biocomplexity Thesaurus, Agricultural Library Thesaurus White Sands National Park Paleolake Otero footprints radiocarbon dating last glacial maximum USGS Metadata Identifier USGS:6036950cd34eb12031174c77 NONE White Sands National Park New Mexico Chihuahuan Desert NONE Unless otherwise stated, all data, metadata and related materials are considered to satisfy the quality standards relative to the purpose for which the data were collected. Although these data and associated metadata have been reviewed for accuracy and completeness and approved for release by the U.S. Geological Survey (USGS), no warranty expressed or implied is made regarding the display or utility of the data on any other system or for general or scientific purposes, nor shall the act of distribution constitute any such warranty. Pigati, Jeffrey S. Mailing Address

USGS, MS 980, Box 25046, Denver Federal Center

Denver CO 80225 303-236-7870 303-236-5349 jpigati@usgs.gov n/a No formal attribute accuracy tests were conducted. Map elements and Topology were checked if needed. No formal logical accuracy tests were conducted. Data set is considered complete for the information presented. Location data collected with handheld GPS, accuracies unknown. Excavation: The site at White Sands National Park (WHSA) Locality 2 was selected for excavation as result of (a) an initial ground-penetrating-radar survey by T.M.U. that revealed potential targets following the method outlined in Urban et al. (17); (b) field prospecting over several years by D.B. that revealed potential tracks at the surface by color contrasts; (c) preliminary 14C ages that established the general age of the deposits based on samples collected in April 2019 by D.B., K.B.S., and J.S.P. along a transect ~50 m north of WHSA Locality 2; and (4) a preliminary surface excavation in September 2019, conducted by D.B., P.M., C.C., and M.R.B. The main east-west trench was cut in January 2020 perpendicular to the slope using a mini trencher (dirt-rated chainsaw) coupled with manual block removal. The north-south trench was also cut in January 2020. The base of the cut blocks broke along natural bedding planes facilitating this process while also exposing in situ bedding planes in the floor of the trench. Loose excavated sediment was sieved, but no artifacts were recovered. Figure S2 details the southern wall of the main east-west trench, which was prepared for sampling. Footprint recovery: Best practices for ichnological studies, as set out in Falkingham et al. (30) and Bennett and Budka (31) were followed. Two scales of structure from motion (SfM) photogrammetry were used. Closeup methods were used to capture individual traces identified in the field in 3D using between 30 and 40 oblique photographs with models generated via OpenMVG (https://github.com/openMVG/openMVG) running as part of the freeware DigTrace (www.digtrace.co.uk). Individual models were scaled, and auto-rotated to the principal plane. Color rendering was undertaken in Cloud Compare (https://www.danielgm.net/cc) having first applied a Delaunay triangulation. Small-scale photogrammetry of the whole site and tracked surfaces was completed using Agisoft Metashape v.1.5.2 (https://www.agisoft.com) with an emphasis on producing orthomosaic images. Footprint analysis: Landmarks were placed (Fig. S3) on 3D models in DigTrace to determine basic dimensions and for a comparative analysis with other 3D footprints. A total of 33 complete tracks from all tracked surfaces (TH1-TH7) were used in the comparative analysis. These were compared to 341 modern footprints made by volunteers in a shallow sand tray (32). A further 78 unpublished Holocene fossil footprints from Namibia were also used in this analysis. Details on these sites can be found in Morse et al. (33) and Bennett et al. (34). The modern tracks and Namibian tracks were imaged using a Konica-Minolta Vi900 optical laser scanner. Landmarks were subject to Generalized Procrustes Analysis (GPA) removing aspects of size and the subsequent coordinates were used in principal component analysis (PCA) optimized for geometric analysis within the software PAST v4.03 (35). Radiocarbon dating: The samples were treated at the U.S. Geological Survey Radiocarbon Laboratory in Denver, CO, using the standard acid-base-acid (ABA) procedure. The ABA treatment included an initial acid wash with 1N HCl at 60 °C for 30 minutes to remove carbonate minerals, a base wash with 1N NaOH at 60 °C for 30 minutes to remove humic acids and other base-soluble compounds (this step was repeated until the supernatant remained clear), and a final acid wash in 1N HCl at 60 °C for at least 10 minutes to acidify the sample. The treated samples were washed with ASTM Type 1, 18.2 MΩ water and dried. Pretreated seeds were initially heated to 150 °C for 15 minutes under vacuum to drive off atmospheric gases and then combusted online at 625 °C in the presence of excess high-purity oxygen. Water and other contaminant gases (including SOx, NOx, and halide species) were removed by precise cryogenic separation at -140 °C using a variable temperature trap capable of holding temperatures to within 1-2 °C of the desired target. The resulting purified CO2 gas was measured manometrically, converted to graphite using an iron catalyst and hydrogen reduction (56), and submitted for AMS 14C analysis. The 14C ages were calibrated using the IntCal20 dataset (33) and OxCal v.4.4.2 (34). Ages are presented in thousands of calibrated years before present (ka = thousands of years before present; 0 ka = 1950 CE), and uncertainties are given at the 95% (2σ) confidence level (Table S5). Uranium-series dating: Aliquots of gypsum sand were weighed into Teflon™ PFA vials, 2 mL of 6N HCl was added, and then samples were immediately spiked with known amounts of a 236U-233U-229Th mixed-isotope tracer. Samples were first digested for approximately 24 hours in 6N HCl at atmospheric pressure at 90 °C. The samples were then centrifuged, and the supernatant solution was separated from insoluble residue. The supernatant was then dried and redissolved in 7N HNO3. HCl-insoluble residue was then further digested using a 2:1 mix of concentrated HF and concentrated HNO3 for approximately 24 hours at atmospheric pressure at 90 °C. Following this digestion, the supernatant was separated, dried, and redissolved in 7N HNO3 as before. After this second digestion step was complete, significant undissolved residue remained. After inspection under the binocular microscope, this residue was clearly dominated by undissolved gypsum. Total digestion of samples was not obtained; therefore, apparent U and Th concentrations are inaccurate and not reported. The HCl and HF leachates were combined and equilibrated in 7N HNO3 overnight prior to column chemistry. U and Th were separated and purified by ion chromatography using Biorad™ AG1×8 (200-400 mesh) resin. Resulting U salts were loaded on the evaporation side of rhenium double-filament assemblies. Th salts were loaded onto single rhenium filament assemblies as a sandwich between layers of graphite suspension. Isotope ratios were obtained on a Thermo Finnigan Triton™ thermal ionization mass spectrometer using a single ETP™ discrete dynode electron multiplier operating in peak-jumping mode. Activity ratios (AR) were determined using decay constants for 234U and 230Th from Cheng et al. (58) and for 238U and 232Th from Steiger and Jäger (59). U isotopic compositions of NIST SRM 4321B U-isotope standard determined during the measurement period yielded an average 234U/235U AR of 0.0073147±0.000007 (±2, n=5), which is within analytical uncertainty of the certified value of 0.007294±0.000028. U isotope ratios for unknown materials were normalized by the factor required to correct the 234U/235U values for the NIST standard measured at the same time. Internal laboratory standards were also measured to monitor data quality. Results for a solution of uranium ore from the Schwartzwalder mine yielded an average 234U/238U AR of 0.9976±0.0028 and an average 230Th/238U AR of 1.0001±0.0041 (±2, n=1), which are within analytical uncertainty of the secular equilibrium values of 1.000 expected for the 69.3-Ma ore (60). Results for an in-house late Pleistocene Acropora coral dating standard (age of 119.6±1.9 ka) yielded an average age of 120.6±1.2 ka (±2, N=1) and an initial 234U/238U AR value of 1.150±0.002 (±2), which is within uncertainty of accepted values for modern seawater (1.150±0.0060) (61). Measured AR values for samples were corrected for detrital 230Th assuming a uniform detrital composition with a Th/U ratio equivalent to average continental crust (Th/U = 4±2) (62-64) and U-series isotopes in secular equilibrium (234U/238U AR = 1.0±0.10, 230Th/238U AR = 1.0±0.25). Detrital correction was performed and sample 230Th/U ages and initial 234U/238U ratios were calculated from detritus-corrected isotope ratios using the implementation of the Isoplot program (65) in R, called IsoplotR (66). All uncertainties are given at 2 [sigma] and include errors from within-run counting statistics, external errors based on reproducibility of standards, and errors propagated from uncertainties assigned to the assumed detrital component and the amount of detrital material present in each sample. Note: References, tables, and figures cited above can be found in the Supplemental Information of the associated journal article. 2021 Universal Transverse Mercator 11 0.9996 -117.0 0.0 500000.0 0.0 coordinate pair 0.001 0.001 meters WGS84 GRS_1980 6378206.4 294.98 Entity and Attribute Overview Table_Name Field_name Definition Units Valid_values_or_range_of_valid_values 1_Footprint_summary_information Track horizon Unique_track_horizon_identifier n/a n/a 1_Footprint_summary_information Track Unique_track_identifier n/a n/a 1_Footprint_summary_information Trackway Unique_trackway_identifier n/a n/a 1_Footprint_summary_information Heel-D1_length Length_between_heel_and_digit_D1 mm 167.9_to_286.2 1_Footprint_summary_information Stature Approximate_height_of_individual mm 1.12_to_1.91 1_Footprint_summary_information Age Age_of_individual years 4.87_to_15.85 1_Footprint_summary_information SE Standard_error_of_the_age_of_individual years 0.08_to_0.43 1_Footprint_summary_information Q75 3rd_quartile_or 75th_percentile_of_the_age_of_individual years 5.33_to_17.17 2_Walking_speed_estimates Trackway Unique_trackway_identifier n/a n/a 2_Walking_speed_estimates Foot_length Length_of_foot centimeters 22.17_to_26.51 2_Walking_speed_estimates SE Standard_error centimeters 1.18_to_9.1 2_Walking_speed_estimates Step_Length Length_of_step centimeters 39.3_to_62.59 2_Walking_speed_estimates Speed Average_speed meters_per_second 0.56_to_1.34 2_Walking_speed_estimates Max Maximum_speed meters_per_second 0.77_to_1.69 2_Walking_speed_estimates Min Minimum_speed meters_per_second 0.37_to_1.09 2_Walking_speed_estimates N Number_of_step_lengths n/a 1_to_3 3_Mininum_Number_of_Trackmakers Track horizon Unique_track_horizon_identifier n/a n/a 3_Mininum_Number_of_Trackmakers Range Range_of_track_lengths mm 30.49_to_122.89 3_Mininum_Number_of_Trackmakers Sigma-1 Average_of_tracks_in_trackways_present person_or_people 1_to_4 3_Mininum_Number_of_Trackmakers Sigma-2 Maximum_based_on_trackways_present person_or_people 1_to_3 3_Mininum_Number_of_Trackmakers Sigma-3 Minimum_based_on_trackways_present person_or_people 1_to_5 3_Mininum_Number_of_Trackmakers Sigma-4 Value_used_by_Webb_et_al. person_or_people 1_to_5 3_Mininum_Number_of_Trackmakers Sigma-5 Average_of_18_Homo_sapiens_trackways_with_at_least_10_tracks person_or_people 1_to_3 4_Footprint_summary_information_for_TH4 Track horizon Unique_track_horizon_identifier n/a n/a 4_Footprint_summary_information_for_TH4 Track Unique_track_identifier n/a n/a 4_Footprint_summary_information_for_TH4 Trackway Unique_trackway_identifier n/a n/a 4_Footprint_summary_information_for_TH4 Heel-D1_length Length_between_heel_and_digit_D1 mm 158.15_to_281.04 4_Footprint_summary_information_for_TH4 Stature Approximate_height_of_individual mm 1.05_to_1.87 4_Footprint_summary_information_for_TH4 Age Age_of_individual years 4.12_to_16.51 4_Footprint_summary_information_for_TH4 SE Standard_error_of_the_age_of_individual years 0.08_to_0.21 4_Footprint_summary_information_for_TH4 Q75 3rd_quartile_or 75th_percentile_of_the_age_of_individual years 4.79_to_17.46 5_Radiocarbon_sample_info_for_Locality_2 Sample_no Unique_sample_identifier n/a n/a 5_Radiocarbon_sample_info_for_Locality_2 AMS_no Unique_accelerator_mass_spectrometer_identifier n/a n/a 5_Radiocarbon_sample_info_for_Locality_2 Elevation Elevation_above_sea_level 1197.14_to_1197.36 5_Radiocarbon_sample_info_for_Locality_2 Material_dated Type_of_material_dated n/a 5_Radiocarbon_sample_info_for_Locality_2 no_seeds Number_of_seeds_dated 40_to_80 5_Radiocarbon_sample_info_for_Locality_2 14C_age Radiocarbon_ages thousands_of_radiocarbon_years_before_present 17.47_to_19.02 5_Radiocarbon_sample_info_for_Locality_2 plus_minus Age_uncertainties_of_radiocarbon_ages thousands_of_radiocarbon_years_at_the_1_sigma_(68%)_confidence_level 0.09_to_0.12 5_Radiocarbon_sample_info_for_Locality_2 Cal_age_range_minimum Minimum_calibrated_ages thousands_of_years_before_present 21.38_to_23.18 5_Radiocarbon_sample_info_for_Locality_2 Cal_age_range_maximum Maximum_calibrated_ages thousands_of_years_before_present 20.88_to_22.57 5_Radiocarbon_sample_info_for_Locality_2 Cal_age Mean_calibrated_ages thousands_of_years_before_present 21.13_to_22.87 5_Radiocarbon_sample_info_for_Locality_2 plus_minus Age_uncertainties thousands_of_years_at_the_2_sigma_(95%)_confidence_level 0.23_to_0.32 6_Uranium_series_sample_info_for_Locality_2 Sample_no Unique_sample_identifier n/a n/a 6_Uranium_series_sample_info_for_Locality_2 Sample_weight Sample_weight grams 0.14838_to_0.27579 6_Uranium_series_sample_info_for_Locality_2 232Th/238U_AR Activity_ratios_of_232Th/238U n/a 0.238_to_0.445 6_Uranium_series_sample_info_for_Locality_2 plus_minus Uncertainties_of_activity_ratios_of_232Th/238U n/a 0.002_to_0.007 6_Uranium_series_sample_info_for_Locality_2 230Th/_238U_AR Activity_ratios_of_230Th/_238U n/a 0.497_to_1.165 6_Uranium_series_sample_info_for_Locality_2 plus_minus Uncertainties_of_activity_ratios_of_230Th/_238U n/a 0.005_to_0.074 6_Uranium_series_sample_info_for_Locality_2 234U/_238U_AR Activity_ratios_of_234U/_238U n/a 1.470_to_1.884 6_Uranium_series_sample_info_for_Locality_2 plus_minus Uncertainties_of_activity_ratios_of_234U/_238U n/a 0.006_to_0.034 6_Uranium_series_sample_info_for_Locality_2 230Th/_232Th_AR Activity_ratios_of_230Th/_232Th n/a 1.72_to_2.77 6_Uranium_series_sample_info_for_Locality_2 230Th/238U_AR Activity_ratios_of_230Th/238U n/a 0.382_to_1.253 6_Uranium_series_sample_info_for_Locality_2 plus_minus Uncertainties_of_activity_ratios_of_230Th/238U n/a 0.028_to_0.074 6_Uranium_series_sample_info_for_Locality_2 234U/238U_AR Activity_ratios_of_234U/238U n/a 1.669_to_2.124 6_Uranium_series_sample_info_for_Locality_2 plus_minus Uncertainties_of_activity_ratios_of_234U/238U n/a 0.062_to_0.163 6_Uranium_series_sample_info_for_Locality_2 Initial_234U/238U_AR Initial_activity_ratios_of_234U/238U n/a 1.745_to_2.312 6_Uranium_series_sample_info_for_Locality_2 plus_minus Uncertainties_of_initial_activity_ratios_of_234U/238U n/a 0.056_to_0.188 6_Uranium_series_sample_info_for_Locality_2 230Th/U_Age Uranium_series_ages thousands_of_years_before_present 24.80_to_100.56 6_Uranium_series_sample_info_for_Locality_2 plus_minus Age_uncertainties thousands_of_years_at_the_2_sigma_(95%)_confidence_level 8.65_to_22.54 7_Radiocarbon_sample_info_near_Locality_2 Sample_no Unique_sample_identifier n/a n/a 7_Radiocarbon_sample_info_near_Locality_2 AMS_no Unique_accelerator_mass_spectrometer_identifier n/a n/a 7_Radiocarbon_sample_info_near_Locality_2 Elevation Elevation_above_sea_level 1196.73_to_1197.90 7_Radiocarbon_sample_info_near_Locality_2 Material_dated Type_of_material_dated n/a 7_Radiocarbon_sample_info_near_Locality_2 no_seeds Number_of_seeds_dated 45_to_130 7_Radiocarbon_sample_info_near_Locality_2 14C_age Radiocarbon_ages thousands_of_radiocarbon_years_before_present 17.02_to_19.40 7_Radiocarbon_sample_info_near_Locality_2 plus_minus Age_uncertainties_of_radiocarbon_ages thousands_of_radiocarbon_years_at_the_1_sigma_(68%)_confidence_level 0.09_to_0.12 7_Radiocarbon_sample_info_near_Locality_2 Cal_age_range_minimum Minimum_calibrated_ages thousands_of_years_before_present 20.83_to_23.75 7_Radiocarbon_sample_info_near_Locality_2 Cal_age_range_maximum Maximum_calibrated_ages thousands_of_years_before_present 20.36_to_23.06 7_Radiocarbon_sample_info_near_Locality_2 Cal_age Mean_calibrated_ages thousands_of_years_before_present 20.59_to_23.41 7_Radiocarbon_sample_info_near_Locality_2 plus_minus Age_uncertainties thousands_of_years_at_the_2_sigma_(95%)_confidence_level 0.21_to_0.39 8_Radiocarbon_sample_info_context_sections Sample_no Unique_sample_identifier n/a n/a 8_Radiocarbon_sample_info_context_sections AMS_no Unique_accelerator_mass_spectrometer_identifier n/a n/a 8_Radiocarbon_sample_info_context_sections Elevation Elevation_above_sea_level 1193.20_to_1197.40 8_Radiocarbon_sample_info_context_sections Material_dated Type_of_material_dated n/a 8_Radiocarbon_sample_info_context_sections 14C_age Radiocarbon_ages thousands_of_radiocarbon_years_before_present 17.69_to_24.55 8_Radiocarbon_sample_info_context_sections plus_minus Age_uncertainties_of_radiocarbon_ages thousands_of_radiocarbon_years_at_the_1_sigma_(68%)_confidence_level 0.10_to_0.17 8_Radiocarbon_sample_info_context_sections Cal_age_range_minimum Minimum_calibrated_ages thousands_of_years_before_present 21.84_to_29.17 8_Radiocarbon_sample_info_context_sections Cal_age_range_maximum Maximum_calibrated_ages thousands_of_years_before_present 21.01_to_28.42 8_Radiocarbon_sample_info_context_sections Cal_age Mean_calibrated_ages thousands_of_years_before_present 21.43_to_28.79 8_Radiocarbon_sample_info_context_sections plus_minus Age_uncertainties thousands_of_years_at_the_2_sigma_(95%)_confidence_level 0.26_to_0.42 0_Data_Dictionary_WHSA_trackway_study.csv 1_Footprint_Summary_Information_WHSA_trackway_study.csv 2_Walking_Speed_Estimates_WHSA_trackway_study.csv 3_Minimum_Number_of_Trackmakers_WHSA_trackway_study.csv 4_Footprint_Summary_Information_for_TH4_WHSA_trackway_study.csv 5_Radiocarbon_Sample_Information_for_Locality_2_WHSA_trackway_study.csv 6_Uranium-series_Sample_Information_for_Locality_2_WHSA_trackway_study.csv 7_Radiocarbon_Sample_Information_near_Locality_2.csv 8_Radiocarbon_Sample_Information_for_context_sections.csv U.S. Geological Survey - ScienceBase mailing address

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Denver Colorado 80225 USA 303-236-7870 303-236-5349 jpigati@usgs.gov FGDC FGDC-STD-001-1998 none none