Research ArticleANTHROPOLOGY

Pre-Clovis projectile points at the Debra L. Friedkin site, Texas—Implications for the Late Pleistocene peopling of the Americas

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Science Advances  24 Oct 2018:
Vol. 4, no. 10, eaat4505
DOI: 10.1126/sciadv.aat4505
  • Fig. 1 Block A at the Debra L. Friedkin site.

    (A) Map showing the location of the Debra L. Friedkin site along Buttermilk Creek. The geomorphic setting of the site is shown along with the location of the excavated areas. The red-colored area is Block A. The location of the four optically stimulated luminescence (OSL)–dated columns is indicated. Solid squares and rectangles indicate the location of trenches and excavation units. T-1, Terrace 1; T-2, Terrace 2. The inset map shows the location of the Friedkin site in Texas. (B) Map of Block A excavation area and the year each area was excavated. OSL sample locations are shown. Geological sections A-A′, B-B′, and C-C′ are indicated with dashed lines and correlate with Figs. 2 and 3. Modern topographic contours are shown with elevations in meters above datum (m AD). (C) Photograph of the floodplain sediments (north wall of excavation unit N1312 E1362). Late Archaic hearth feature occurs near the top of the section, and the complete lanceolate stemmed point (AM9875-2) dating ~15 ka ago is seen in the excavation unit at the base of the wall profile. Photo Credit: Michael Waters, Texas A&M University.

  • Fig. 2 Cross section A-A′ showing the site stratigraphy, location of time-diagnostic artifacts, and Bayesian-modeled OSL ages.

    Archaeological time periods are as follows: Late Prehistoric/Late Archaic (LP/LA), Middle Archaic/Early Archaic (MA/EA), Late Paleoindian (LP), Folsom/Clovis, and Buttermilk Creek Complex (BCC). Some Late Prehistoric and Late Archaic artifacts appear above the profile because there are places where the ground surface is higher than the contour line along the A-A′ profile (see Fig. 1B for the location of this cross section). OSL ages from 2008 and 2015 are shown. The location of each pre-Clovis projectile point is identified, and the artifact number beginning with the designation AM allows identification of specific artifacts. This profile includes all artifacts 3.5 m west and east of the A-A′ line from 91.15 m AD to the surface because of the surface slope. All artifacts 5.5 m west and east of the A-A′ line between 90.5 and 91.5 m AD are shown because the deposits are horizontal. All artifacts 3.5 m west and east of the A-A′ line below 90.5 m AD are shown because the deposits slope to the east.

  • Fig. 3 Cross sections B-B′ and C-C′ showing the site stratigraphy, location of time-diagnostic artifacts, and Bayesian-modeled OSL ages.

    Archaeological time periods are as follows: Late Prehistoric/Late Archaic (LP/LA), Middle Archaic/Early Archaic (MA/EA), Late Paleoindian (LP), Folsom/Clovis, and Buttermilk Creek Complex (BCC). Some Late Prehistoric and Late Archaic artifacts appear above the C-C′ profile because there are places where the ground surface is higher than the contour line along this transect (see Fig. 1B for the location of these cross sections). The location of each pre-Clovis projectile point is identified, and the artifact number beginning with the designation AM allows identification of specific artifacts. The B-B′ profile includes all OSL ages and artifacts from the areas excavated in 2015 and 2016. The C-C′ profile includes all OSL ages and artifacts from the areas excavated in 2007, 2008, 2009, and 2011.

  • Fig. 4 Lithic artifact counts by depth and maps of diagnostic artifacts for Block A.

    (A) Total artifacts from 52 units with comparable data for all horizons excavated between 2009 and 2016, including all tools and debitage >0.625 cm in size, by 5-cm levels for the Late Archaic (LA), Middle/Early Archaic (MA/EA), Late Paleoindian (LP), Folsom/Clovis (F/C), and Buttermilk Creek Complex (BCC) horizons. (B) Total formal and informal tools from 52 units with comparable data for all horizons excavated from 2009 to 2016 (>0.625 cm in size) by 5-cm levels. (C) Counts of formal and informal tools from all 104 units from 2006 to 2016 (>0.625 cm in size for only the LP, F/C, and BCC layers) at 2.5-cm levels. Occurrence of artifacts below 90.15 m AD is accounted for by the slope of the BCC artifact–bearing deposits. (D) Counts of formal and informal tools from 2015 to 2016 excavations >0.625 cm in size for the LP, F/C, and BCC layers west of E1363. (E) Counts of formal and informal tools from 2015 to 2016 excavations >0.625 cm in size for the LP, F/C, and BCC layers east of E1363. (F) Horizontal distribution of diagnostic artifacts by archaeological component for Block A.

  • Fig. 5 Pre-Clovis projectile points from the Debra L. Friedkin site and other sites in North America.

    (A) Triangular lanceolate point (AM9811-1), (B) lanceolate stemmed point (AM9875-2), (C) lanceolate stemmed point midsection with base and blade sections (AM12017-1), (D) lanceolate stemmed point midsection with base and blade sections (AM6233-1), (E) lanceolate stemmed point midsection with base and blade sections (AM12271-1), (F) point tip (AM4668-6), (G) lanceolate stemmed point base (AM8286-16), (H) point midsection (AM4819-7), (I) beveled point tip (AM12170-1), (J) beveled point tip (AM8380-3), (K) beveled point tip midsection (AM12029-2), and (L) point tip (AM12274-13). (M) Point from Iztapan Mammoth II, Mexico [from (29)], (N) point from Iztapan Mammoth II, Mexico [from (29)], (O) point from Iztapan Mammoth I, Mexico [from (29)], and (P) Miller point from Meadowcroft Rockshelter, Pennsylvania.

  • Fig. 6 Proposed models explaining the peopling of the Americas.

    (A) The earliest people exploring the Americas used stemmed projectile points and traveled along the coast ~16 ka ago, moved inland, and reached the Debra L. Friedkin site by ~15.5 ka ago and South America by ~14.2 ka ago (blue arrows). (B) A triangular lanceolate projectile point form develops in situ from the earlier lanceolate stemmed form ~14 ka ago, with Clovis developing ~13 ka ago and spreading across most of the United States and northern Mexico (red arrows). (C) Alternatively, the origin of Clovis may be explained by a second migration that occurs with people using triangular lanceolate points traveling through the ice-free corridor and reaching the Friedkin site by ~14 ka ago. Clovis develops in situ ~13 ka ago and spreads across central and eastern North America (red arrows). Archaeological sites with ages are shown. Colored regions on the map show the general distribution of Clovis, with highest densities in the east (brown), moderate densities in the central United States (orange), and light densities in the west (yellow), overlapping with the Western Stemmed Tradition shown by the cross-hatch pattern.

Supplementary Materials

  • Supplementary material for this article is available at http://advances.sciencemag.org/cgi/content/full/4/10/eaat4505/DC1

    Supplementary Text

    Fig. S1. Bayesian ages of Block A OSL columns.

    Fig. S2. Regenerative growth curves and plots of De values for six OSL samples.

    Fig. S3. Preheat dose recovery test for sample BG4066 that was completed for two initial doses of 8 and 31 Gy.

    Fig. S4. Diagnostic Folsom and Clovis artifacts.

    Fig. S5. Clovis bifaces.

    Fig. S6. Pre-Clovis projectile points.

    Fig. S7. Pre-Clovis bifaces.

    Fig. S8. Use-wear on pre-Clovis artifacts.

    Table S1. OSL ages on 4- to 11-μm quartz grains for sediments from the Debra L. Friedkin site, Texas.

    Table S2. Correlation of OSL ages with archaeological horizons.

    Table S3. Clovis, Folsom, and Buttermilk Creek Complex bifaces.

    References (47, 48)

  • Supplementary Materials

    This PDF file includes:

    • Supplementary Text
    • Fig. S1. Bayesian ages of Block A OSL columns.
    • Fig. S2. Regenerative growth curves and plots of De values for six OSL samples.
    • Fig. S3. Preheat dose recovery test for sample BG4066 that was completed for two initial doses of 8 and 31 Gy.
    • Fig. S4. Diagnostic Folsom and Clovis artifacts.
    • Fig. S5. Clovis bifaces.
    • Fig. S6. Pre-Clovis projectile points.
    • Fig. S7. Pre-Clovis bifaces.
    • Fig. S8. Use-wear on pre-Clovis artifacts.
    • Table S1. OSL ages on 4- to 11-μm quartz grains for sediments from the Debra L. Friedkin site, Texas.
    • Table S2. Correlation of OSL ages with archaeological horizons.
    • Table S3. Clovis, Folsom, and Buttermilk Creek Complex bifaces.
    • References (47, 48)

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