Geochemical properties -- Covariate calculation

[sigmafelix]

Targets

1. National Geochemical Database: Soil
2. National Geochemical Database: Rock
3. National Geochemical Survey Database

File footprints

• All are negligible (<1 GB)

Strategy

• Point data; nearest spatial join

[sigmafelix]

10/10/2023

• National Geochemical Survey Database: used principal analytical methods (ICP40 and AA) -> reference
• National Geochemical Database-- Soil: 81 elements are included (with unit in the column name);
  • Multiple measurements from the same lab analysis are summarized as:
    • Negative values (with flags indicating "less than the value given" (reference): the largest value
    • Both negative and positive values are present: maximum positive value
    • Positive values: maximum positive value
    • No measurement: NA
• National Geochemical Database-- Rock: rock type (metamorphic, igneous, sedimentary ...) and geologic age are taken. All are categorical