DOI: 10.5061/dryad.tqjq2bw52
title: Starch granule analysis of bedrock metates in Warner Valley, Oregon

description: Starch-rich geophytes are a highly-valued food among many human societies.
 For example, Indigenous people in the northern Great Basin plan social
 activities around the seasonal foraging of bulbs, roots, and tubers.
 Despite such obvious dietary and cultural importance, the antiquity of
 geophyte use in the Great Basin remains difficult to establish. Herbaceous
 underground storage organs do not preserve well in the archaeological
 record. Therefore, most studies rely on indirect evidence to infer
 geophyte consumption by hunter-gatherers during the late Pleistocene/early
 Holocene.  It has been suggested that bedrock metates found among
 upland rock art sites in the northern Great Basin reflect seasonal
 geophyte exploitation over 14,000 years. Our study tests this hypothesis
 by analyzing starch residue extracted from bedrock metates at three
 archaeological sites in the uplands of Warner Valley, Oregon. Species of
 biscuit root (Lomatium) were collected in the field and sampled for
 starch. Systematic studies conducted on granules defined morphological
 characteristics were then applied to the identification of archaeological
 granules. Starch granules from geophytes, specifically Lomatium spp., were
 identified on metate surfaces at all sites, thereby providing direct
 evidence for the collection and processing of geophytes. These results
 support previous hypotheses regarding Paleoindian foraging strategies in
 the northern Great Basin.
description: <em>Reference
 Materials</em>. Our approach to identifying
 archaeological starch granules from bedrock metates began with a
 systematic study of <em>Lomatium</em> granules extracted from
 extant plant populations within the vicinity of the sites (Louderback et
 al. 2022b). Three <em>Lomatium </em>species (<em>L.
 donnellii, L. macrocarpum, </em>and<em> L.
 triternatum</em>)<em> </em>were collected and each
 taproot (n = 3 per species) was sampled for starch (Figure 3).<em>
 </em>Using randomly generated X-Y coordinates on the microscope
 stage, morphological characteristics (e.g., size, shape, surface features)
 of 100 starch granules from each taproot (n=900 granules total) were
 measured and described (see Louderback et al. 2022a for descriptions of
 morphological characteristics). The frequency of those characteristics
 occurring on granules was calculated and expressed as a number between 0.0
 and 1.0. This approach allowed us to develop a set of statistically
 defined characteristics frequently observed in
 <em>Lomatium</em> granules, which can then be applied to the
 identification of archaeological granules. <em>Sample Collection in
 the Field</em>. Starch samples were
 collected from the surfaces of 58 bedrock metates from all three sites
 (Barry Spring n=28, Corral Lake n=6, Long Lake n=24). To minimize
 contamination, nitrile-free disposable gloves were worn throughout the
 extraction process, a new pair for each sample (see Wilks et al, in prep).
 Loose sediment was brushed from metate surfaces prior to sampling.
 Approximately 50 ml of distilled water (DH<sub>2</sub>0) was
 then added to the stone surface and cleaned with an ultrasonic brush. A
 sterile syringe was then used to transfer the DH<sub>2</sub>0
 and sediment to a sterile test tube labeled
 <strong>‘<em>metate surface</em>’</strong>. This
 was repeated until the DH<sub>2</sub>0 wash was clear.
 Next, 50 ml of a 2.5 percent
 solution of sodium hexametaphosphate (Na-Hex) was added to the cleaned
 bedrock surfaces to deflocculate residue that was more deeply embedded in
 the stone’s interstitial matrix. After about one hour ~ 50ml of
 DH<sub>2</sub>0 was added and a sterile electric toothbrush
 was used to vigorously clean the surface for five minutes. A sterile
 syringe was then used to transfer the resultant serum to a 50 ml test tube
 labeled <strong>‘<em>metate
 interstitial</em>’</strong>. <em>Control
 Samples.</em> Thirteen control samples
 (Barry Spring n=6, Corral Lake n=1, Long Lake n=6) were also collected
 from non-worked or non-cultural stone surfaces approximately 5–10 meters
 from the sampled archaeological bedrock metates. Figure 4 demonstrates the
 location of control samples in relation to sampled surfaces at Long Lake.
 These control samples were collected at each site and treated in the same
 way as the surface and interstitial starch samples. Control samples were
 labeled <strong><em>‘control’</em></strong> and
 numbered consecutively as they were collected in the field. The purpose is
 to compare the control sample residue to the residue extracted from the
 bedrock metate. Although non-cultural stone surfaces in the vicinity of
 bedrock metates may have been contaminated with starch from associated
 plant materials, this source would have insignificant levels of starch
 granules when compared to starch granules ground into the stone matrix of
 bedrock cultural features and artifacts. <em> Laboratory
 Analysis</em>. All samples were processed
 in the Archaeobotany lab at the Natural History Museum of Utah (NHMU).
 Each residue serum was sieved through a 125 <em>μm </em>mesh Endecott sieve into a beaker
 using deionized water (DiH<sub>2</sub>0). Sample water
 &gt;125 <em>μm </em>was discarded, while sampled portion
 &lt;125 <em>μm </em>was retained and transferred to a 50 ml test tube and
 centrifuged for 3 minutes at 3000 RPM. The supernatant was then discarded,
 the sample pellet transferred to a new 15 ml test tube, re-suspended with
 ~10 ml of DiH<sub>2</sub>0, mixed with a vortex, and centrifuged
 for 3 minutes at 3000 RPM. Approximately, 7 ml of Lithium
 heteropolytungstate (LST:
 specific
 gravity 2.2) was added, resuspended with a vortex mixer then
 centrifuged for 15 minutes at 1000 RPM. The starch samples were
 extracted
 from
 the
 surface of the heavy liquid using a pipette and transferred
 to a freshly labeled 15 ml test tube. To remove any residual heavy liquid
 each sample was rinsed 2–3 times with ~10 ml
 of DiH<sub>2</sub>0, vortexed, and centrifuged for 3
 minutes at 3000 RPM. The sample was then decanted and resuspended with
 ~7ml of acetone, mixed with a vortex, and centrifuged for 3 minutes at
 3000 RPM. The acetone was decanted and samples were covered and left to
 dry overnight. Individual samples were reconstituted with 50%
 DiH<sub>2</sub>0
 and 50% glycerol and mounted
 on
 a glass
 slide for observation.
 Each slide was scanned in its entirety using a transmitted brightfield
 microscope fitted with polarizing filters and Nomarski optics (Zeiss
 Axioscope 2, Zeiss International, Göttingen, Germany). Starch granules
 were photographed under 400x magnification with a digital camera (Zeiss
 HRc) and measured with Zeiss Zen
 software.
description: # This readme file was generated on 2023-08-21 by Stefania Wilks; Starch
 Granule Analysis of Bedrock Metates in Warner Valley, Oregon GENERAL
 INFORMATION 1\. Title of Dataset: Starch Granule Analysis of Bedrock
 Metates in Warner Valley\, Oregon A. Author/Principal Investigator
 Information Name: Stefania Wilks ORCHID:0000-0003-3752-8856 Institution:
 Natural History Museum of Utah, Department of Anthropology, University of
 Utah Address: 301 Wakara Way, Salt Lake City, Utah 84108 Email:
 stefania.wilks@anthro.utah.edu 2\. Date of data collection: 6/2021\-8/2023
 3\. Geographic location of data collection: Lakeview\, Oregon\, and the
 Natural History Museum of Utah\, University of Utah\, Salt Lake City\,
 Utah 4\. Information about funding sources that supported the collection
 of the data: This project was funded with a United States Bureau of Land
 Management Grant \(L20AS00005\) Lakeview\, Oregon District SHARING/ACCESS
 INFORMATION 1\. Licenses/restrictions placed on data: N/A 2\. Links to
 publications that cite or use the data: N/A 3\. Links to other publicly
 accessible locations of the data: N/A 4\. Links/relationships to ancillary
 data sets: These data sets are referred to in both of the research papers
 cited below. Wilks, S., Louderback, L.A., Simper, H. & W. J.
 Cannon (2024) Geophyte Starch Granules on Bedrock Metates in the Uplands
 of Warner Valley, Oregon. Wilks, S., Paredes, S., and L.A. Louderback
 (2024) Starch Granule Yields from Open-Air Metates Unaffected by
 Environmental Contamination. 5\. Data was derived from another source? NO
 6\. Recommended citation for this dataset: Wilks\, et al \(2024\) Starch
 Granule Analysis of Bedrock Metates in Warner Valley\, Oregon\, Dryad\,
 Dataset DOI: 10\.5061/dryad\.tqjq2bw52 DATA & FILE OVERVIEW 1\.
 File List: LS#, Slide Number, Photo Number, Length(µm),
 Hilum(0=centric/1=eccentric), Lamellae(absent=0/present=1), Extinction
 Cross(0=absent/1=present),
 Shape(0=irregular/1=round/2=angular/3=elongate)\*\*data were combined and
 some observations are recorded as numbers while others are written out\*\*
 Fissures(absent=0/present=1)\*\*fissure-type should be described in the
 notes\*\*, Pressure Facets(absent=0/Present=1), Notes All data includes
 indiviual observations of identifying morphological features on starch
 granules recovered from open-air metates. 2\. Relationship between files\,
 if important: Interstitial starch data are organized by site, each tab is
 a site. Each site's observations are listed by lab sample number. All
 Control and Surface starch data are each organized on one spreadsheet tab.
 3\. Additional related data collected that was not included in the current
 data package: N/A 4\. Are there multiple versions of the dataset? NO
 METHODOLOGICAL INFORMATION Identification and Quantification of
 Archaeological Starch 1\. Starch Reference Materials: Our approach to
 identifying archaeological starch granules from bedrock metates began with
 a systematic study of Lomatium granules extracted from extant plant
 populations within the vicinity of the sites. Three Lomatium species (L.
 donnellii, L. macrocarpum, and L. triternatum) were collected and each
 taproot (n = 3 per species) were sampled for starch. Using randomly
 generated X-Y coordinates on the microscope stage, morphological
 characteristics (e.g., size, shape, surface features) of 100 starch
 granules from each taproot (n=900 granules total) were measured and
 described (see Louderback et al. 2022 for descriptions of morphological
 characteristics). The frequency of those characteristics occurring on
 granules was calculated and expressed as a number between 0.0 and 1.0.
 This approach allowed us to develop a set of statistically defined
 characteristics frequently observed in Lomatium granules, which can then
 be applied to the identification of archaeological granules Granule size
 distributions for each of the species were pooled (n=300 per species) and
 their distributions were plotted. Morphological characteristics occur more
 frequently in the top 20% size range of starch granules, and therefore, we
 report frequencies for those granules (Liu et al. 2014, Louderback et al.
 2017). Seven diagnostic characteristics were used to identify
 archaeological granules of Lomatium spp. (Louderback et al 2022). These
 include 1) 10.7-31.0 µm size range, 2) circular to oval shape, 3) centric
 hilum, 4) distinct extinction cross, 5) fissure (transverse/stellate), 6)
 visible lamellae, and 7) pressure facets. Archaeological starch granules
 exhibiting 6 or 7 characteristics are considered Lomatium spp. Granules
 displaying 4 or 5 characteristics are attributed to their family, Apiaceae
 (Figure). Starches with fewer than 3 characteristics remain
 unidentifiable. 2\. Sample Collection in the Field: Starch samples were
 collected from the surfaces of 58 bedrock metates from all three sites
 (Barry Spring n=28, Corral Lake n=6, Long Lake n=24). Metate surfaces were
 chosen by William Cannon (Lakeview BLM archaeologist) for their
 association with recorded Rock Art Panels. To minimize contamination,
 nitrile-free disposable gloves worn throughout the extraction process were
 switched to a new pair for each sample collection. Loose sediment was
 brushed from metate surfaces prior to sampling. Approximately 50 ml of
 distilled water (DH20) was then added to the stone surface and cleaned
 with an ultrasonic brush. A sterile syringe was then used to transfer the
 DH20 and sediment to a sterile test tube labeled ‘metate surface’. This
 was repeated until the DH20 wash was clear. Next, 50 ml of a 2.5 percent
 solution of sodium hexametaphosphate (Na-Hex) was added to the cleaned
 bedrock surfaces to deflocculate residue that was more deeply embedded in
 the stone’s interstitial matrix. After \~ one hour, \~ 50ml of DH20 was
 added and a sterile electric toothbrush was used to vigorously clean the
 surface for five minutes. A sterile syringe was then used to transfer the
 resultant serum to a 50 ml test tube labeled ‘metate interstitial’. 3\.
 Control Samples: Thirteen control samples (Barry Spring n=6, Corral Lake
 n=1, Long Lake n=6) were also collected from non-worked or non-cultural
 stone surfaces approximately 5-10 meters from the sampled archaeological
 bedrock metates. For example, Figure 4 demonstrates the location of
 control samples in relation to sampled surfaces at Long Lake. These
 control samples were collected at each site and treated in the same way as
 the surface and interstitial starch samples. Control samples were labeled
 ‘control’ and numbered consecutively as they were collected in the field.
 The purpose is to compare the control sample residue to the residue
 extracted from the bedrock metate. Although non-cultural stone surfaces in
 the vicinity of bedrock metates may have been contaminated with starch
 from associated plant materials, this source would have insignificant
 levels of starch granules when compared to starch granules ground into the
 stone matrix of bedrock cultural features and artifacts. 4\. Laboratory
 Processing Methodology: All samples were processed in the Archaeobotany
 lab at the Natural History Museum of Utah (NHMU). Each residue serum was
 sieved through a 125 μm mesh Endecott sieve into a beaker using distilled
 water (DIH20). Sample water &gt;125 μm was discarded, while sampled
 portion &lt;125 μm was retained and transferred to a 50 ml test tube
 and centrifuged for 3 minutes at 3000 RPM. The supernatant was then
 discarded, the sample pellet transferred to a new 15 ml test tube,
 re-suspended with \~10 ml of DIH20, mixed with a vortex, and centrifuged
 for 3 minutes at 3000 RPM. Approximately, 7 ml of Lithium
 heteropolytungstate (LST: specific gravity 2.2) was added, resuspended
 with a vortex mixer then centrifuged for 15 minutes at 1000 RPM. The
 starch samples were extracted from the surface of the heavy liquid using a
 pipette and transferred to a freshly labeled 15 ml test tube. To remove
 any residual heavy liquid each sample was rinsed 2-3 times with \~10 ml of
 DIH20, vortexed, and centrifuged for 3 minutes at 3000 RPM. The sample was
 then decanted and resuspended with \~7ml of acetone, mixed with a vortex,
 and centrifuged for 3 minutes at 3000 RPM. The acetone was decanted and
 samples were covered and left to dry overnight. Individual samples were
 reconstituted with 50% DIH20 and 50% glycerol and mounted on a glass slide
 for observation. Each slide was scanned in its entirety using a
 transmitted brightfield microscope fitted with polarizing filters and
 Nomarski optics (Zeiss Axioscope 2, Zeiss International, Göttingen,
 Germany). Starch granules were photographed under 400x magnification with
 a digital camera (Zeiss HRc) and measured with Zeiss Zen software. 5\.
 Laboratory Analysis: Starch granules were measured and described based on
 a set of established criteria, including maximum length through the hilum
 (µm), hilum position, two-dimensional shape, clarity of the extinction
 cross, and the presence or absence of surface features such as fissures
 and pressure facets (Brown and Louderback 2020; Holst et al., 2007; ICSN,
 2011; Joyce et al 2021; Louderback and Pavlik, 2017; Louderback et al.,
 2022; Musaubach et al., 2013; Piperno et al., 2004, 2009; Reichert, 1913;
 Torrence and Barton, 2016). These criteria were recorded as absent (0) or
 present (1) and expressed as a percentage of the occurrence. Slides were
 scanned with a transmitted brightfield microscope using polarizing filters
 and Nomarski optics (Zeiss Axioskop Imager M1, Zeiss International,
 Göttingen, Germany). Observations were obtained using randomly generated X
 and Y coordinates on the microscope stage. All starch granules observed
 within each field of view were measured and described. Images and
 measurements at 400X were captured under polarized light (POL) with a
 digital camera (Zeiss AxioCam MRc5) using Zen Core 3.1 imaging and
 measurement software. The presence of surface features was imaged and
 recorded in differential interference contrast (DIC) micrographs.
 DATA-SPECIFIC INFORMATION FOR: 1\. File List: LS# (lab-sample number),
 Slide Number, Photo Number, Length(µm), Hilum(0=centric/1=eccentric),
 Lamellae(absent=0/present=1), Extinction Cross(0=absent/1=present),
 Shape(0=irregular/1=round/2=angular/3=elongate)\*\*data were combined and
 some observations are recorded as numbers while others are written out\*\*
 Fissures(absent=0/present=1)\*\*fissure-type should be described in the
 notes\*\*, Pressure Facets(absent=0/Present=1), Notes\*\*All additional
 observations including, GOOD PHOTO\*\* 2\. Missing data codes: n/a