| dd | Data dictionary provided as a download from the repository. |
| geochem | Sample identifiers, characteristics, processing information, and results of chemical analysis. |
| limits | Characteristics of the analytical methods, including limits of detection. |
| locations | Geographic locations of the samples, duplicates information found in the table geochem. |
| qaqc | Analytical results obtained from geochemical reference materials using the same procedures and instruments as were used for the field-collected samples. |
| focus | Associative table relating geochemical sample locations to Earth MRI phase 3 focus areas. |
