Spatial analysis and neotaphonomy data from two landscape bone assemblages in the Ngorongoro

Creator(s): Charles Egeland; Cynthia Fadem

Year: 2024

Summary

Two 100 m x 200 m survey blocks, located approximately one kilometer from each other and referred to as Olduvai Transect 1 (OT1) and Olduvai Transect 2 (OT2), were visited in 2015 (OT1) and 2018 (OT2) at the height of the dry season in mid-June or July. OT1 occurs in a treeless section of the plain , while OT2 contains a stand of trees surrounding a seasonal waterhole (Figure 2). A series of abandoned Maasai homesteads (bomas) were located to the south and to the west of OT2 at the time of data collection. The survey blocks’ borders lie along an arbitrary grid system established with a laser total station. Systematic pedestrian survey was carried out to document the spatial distribution of bone specimens within these borders. The survey team was arranged in a line and spaced one arm’s length apart (~65 cm). The survey line progressed back and forth in transects at a slow walk. Individuals at either end of the survey line used compasses and regularly checked and adjusted spacing to ensure that parallel, non-overlapping transects were maintained. Vegetation is sparse in both survey areas, so ground visibility was generally excellent. All specimens—whether fully exposed or partially buried—were marked with colored pin flags (in some cases, tight clusters of bone specimens were marked with a single pin flag). Partially buried bones were generally quite conspicuous in the soft, fine sand substrate. No attempt was made to identify or recover fully buried material through excavation. While most specimens were encountered during systematic transect survey, a handful were discovered ad hoc, either as the survey team roamed the block between transect runs or as previously flagged bones were being recorded. Each specimen was plotted to the nearest millimeter at its center point with the total station and then collected. Articulated remains were plotted separately. Given the close spacing and slow pace of the survey teams and the excellent visibility, we are confident that high recovery rates were attained for all fully exposed and partially buried remains. Our analysis focuses on all recovered specimens > 2 cm in maximum dimension. To our knowledge, neither survey block experienced any systematic collection in the past, and the presence of bones in weathering stage 5 suggest that both faunal assemblages represent at least 12 years of deposition (Behrensmeyer, 1978). At OT2, all trees equal to or greater than three meters in height were also plotted with the total station by measuring three to five points around the circumference. The resulting points were imported into ArcGIS Pro (version 3.2.0) and connected to form individual polygons. The “Feature to Point” geoprocessing tool calculated the centroid of each polygon. These tree centroids were used for all distance-to-tree calculations (see below). Topographic points were recorded in UTM coordinates with a Trimble GeoXH 6000 and then converted into local total station coordinates. Elevations were recorded as meters above mean sea level.

Cite this Record

Spatial analysis and neotaphonomy data from two landscape bone assemblages in the Ngorongoro. Charles Egeland, Cynthia Fadem. 2024 ( tDAR id: 501009) ; doi:10.48512/XCV8501009

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Data Set Structure

Measurement Column
Count Column
Coded Column
Filename Column
Integration Column (has Ontology)

Table Information: OT_Data

Column Name Data Type Type Category Coding Sheet Ontology Search
CM Cutmark presence/absence
VARCHAR  Uncoded Value Fauna : Modification none none true
TM Fauna modification presence/absence
VARCHAR  Uncoded Value uncategorized none none true
ID Artifact Class: BN=Bone TC=Tree Center TP=Topographic Point
VARCHAR  Uncoded Value uncategorized none none true
Z Elevation
DOUBLE  Uncoded Value uncategorized none none true
E Easting
DOUBLE  Uncoded Value Provenience and Context : East none none true
N Northing
DOUBLE  Uncoded Value Provenience and Context : North none none true
Number Sequential number for artifacts
DOUBLE  Uncoded Value Other : ID none none true
Year Year survey area visited
BIGINT  Uncoded Value Other : Date Created none none true
Location OT1 or OT2 survey area
VARCHAR  Uncoded Value Provenience and Context : Context none none true

Keywords

Spatial Coverage

min long: 35.155; min lat: -3.322 ; max long: 35.99; max lat: -2.801 ;

Individual & Institutional Roles

Contact(s): Charles Egeland

File Information

  Name Size Creation Date Date Uploaded Access
OT_Data.csv 70.08kb Aug 9, 2024 7:32:09 AM Confidential
  • Translated version OT_Data_translated.xlsx (87.66kb)
    Data column(s) in this dataset have been associated with coding sheet(s) and translated: