Authors:
Egeland, Charles, Fadem, Cynthia, Byerly, Ryan, Henderson, Cory, Fitzgerald, Curran, Mabulla, Audax, Baquedano, Enrique, Gidna, Agniss
Abstract:
Variable Description Type Type of sample (calibration = calibration coin for Delta Innov-X Analyzer; standard = NIST geological standard; geological = geological sample from lithic raw material source; artifact = archaeological specimen) Replicate Replicate measurement (Yes or No) Source Geological source (delta = Delta Innov-x Analyzer calibration coin; nist = National Institute of Standards and Technology (NIST) geological standard; NS = Naibor Soit; NH = Naisuisui Hill; OL = Oldonye Okule; LD = Lemagarut drainage; SS = Shifting Sand; KG = Ke (...)
Variable Description Type Type of sample (calibration = calibration coin for Delta Innov-X Analyzer; standard = NIST geological standard; geological = geological sample from lithic raw material source; artifact = archaeological specimen) Replicate Replicate measurement (Yes or No) Source Geological source (delta = Delta Innov-x Analyzer calibration coin; nist = National Institute of Standards and Technology (NIST) geological standard; NS = Naibor Soit; NH = Naisuisui Hill; OL = Oldonye Okule; LD = Lemagarut drainage; SS = Shifting Sand; KG = Kelogi Hills; EN = Engelosin) Outcrop Individual outcrop within geological source (NSM = Naibor Soit Main Hill; NSMH = Naibor Soit Manyata Hill; NSSO = Naibor Soit Southern Outlier; NH = Naisuisui Hill; LD1 = Lemagarut Drainage 1; LD2 = Lemagarut Drainage 2; BKE = BK East; SS = Shifting Sand; KG = Kelogi Hills; EN = Engelosin; NA = Not applicable) Specimen Individual find or sample number Material Raw material type (QTZ = "Quartz-rich"; GN = Gneiss; FGV = Fine-grained volcanic) Element concentration estimate Reported for each element (e.g., P, Cl, Ca; empty cells are "non-detect") Analytical error Reported for each element (e.g., P +/-, Cl +/-, Ca +/-; no error reported for "non-detect" elements) The published analysis focused only on granulite specimens (n = 186) and, more specifically, on six elements (Fe, Ti, Zr, K, Sr, and Y) that had detection rates >75% in the granulite specimens (that is, these elements were detected in more than 75% of the granulite specimens). These elements were used in the predictive models from the published analysis. Two of the 186 granulite specimens were missing values for five out of the six elements and were therefore not included in the statistical analyses. Of the remaining 184 specimens, 55 had missing data for one element, and two of those 55 had missing data for two elements. These missing values were treated as censored data (that is, the element is present but could not be measured precisely enough for the instrument to report a value). These missing values were interpolated in one of two ways. For those specimens subjected to replicate pXRF runs (n = 7), the missing value was replaced with the mean value of the replicates. The missing values for the remaining specimens (n = 48) were replaced with the mean of the four closest (as determined in two-dimensional space) specimens with measured (rather than interpolated) values. The main data file does not include these interpolated values. Should analysts choose to use them, interpolated values can be found in the additional .csv file.
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