Starch granule analysis of bedrock metates in Warner Valley, Oregon
Data files
Sep 26, 2023 version files 56.34 KB
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InterstitialStarchData_DRYAD.xlsx
45.73 KB
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README.md
10.61 KB
Abstract
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.
README: 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 >125 μm was discarded, while sampled portion <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
Methods
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 (Louderback et al. 2022b). Three Lomatium species (L. donnellii, L. macrocarpum, and L. triternatum) were collected and each taproot (n = 3 per species) was sampled for starch (Figure 3). 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 Lomatium granules, which can then be applied to the identification of archaeological granules.
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). 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 (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 about 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’.
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. 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.
Laboratory Analysis. 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 deionized water (DiH20). Sample water >125 μm was discarded, while sampled portion <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.