Description of database fields
| Field |
Description |
| Lab No. |
A reference number to indicate a unique entry in the Canadian Geochronology Knowledgebase |
| Sample No |
sample number - either the sample number indicated in the publication, or one assigned using the rock's published name |
| Age |
The interpreted age of the rock or mineral given in millions of years (Ma). All ages have been corrected to the recommended decay constants of Steiger and Jager (1977). Ar-Ar ages have been corrected to the following apparent ages for monitor standards to better approximate equivalence with U-Pb ages:
| FCT 28.02 Ma | (Renne et al, 1994; 1998; Villeneuve et al, 2001; Baksi et al, 1996) |
| MMhb-1 523.1 Ma | (Renne et al (1998) |
| Hb3gr 1072 Ma | (Roddick, 1983; Turner et al., 1971) |
| TCR 28.34 Ma | (Renne et al, 1998) |
| GA-1550 98.79 Ma | (Renne et al, 1998) |
| Alder Creek 1.194 Ma | (Renne et al, 1998) |
| GHC-305 105.2 Ma | (Renne et al, 1998) |
| LP-6 128.4 Ma | (Baksi et al, 1996) |
| Bern 4 Mu 18.56 Ma | (Baksi et al, 1996) |
| Bern 4 Bi 17.25 Ma | (Baksi et al, 1996) |
The original monitor used to calibrate the age is noted in the notes field. |
| Error Plus |
2 sigma positive uncertainty in Ma. This is 0 when no error is given by the author. |
| Error Minus |
2 sigma negative uncertainty in Ma. This is 0 when no error is given by the author. |
| Age Method |
Isotopic system or methodology used to derive the age (e.g. U-Pb, Ar-Ar, fission track). |
| Age Interpretation |
A general category that describes the type of geological event dated (e.g. cooling, igneous crystallization etc.). |
| Material |
The mineral or material (e.g. whole rock) analyzed. |
| Technique |
The analytical technique used to determine the age (e.g. SHRIMP, TIMS) |
| Qualifier |
A qualifier describing constraints on the age. "Direct" means analytical errors are statistically representative; "Estimate" is used when the author indicates no statistical validity to assigned errors. Other qualifiers include "Maximum Age" (i.e. statistical limit on how old the sample can be) and "Minimum Age" (i.e. statistical limit on how young the sample can be). |
| Note |
A text descriptor highlighting salient features used by the author in arriving at the published interpretation of the date. |
| Geological Province |
A broad category indicating which major geological province the sample was collected from. |
| Province |
Geographic province or territory. |
| Longitude |
Latitude in decimal degrees, NAD27. |
| Latitude |
Latitude in decimal degrees, NAD27. |
| Location |
A text description indicating sample location relative to geographic features. |
| Geological Info |
Description of the geological framework (e.g. unit, formation) |
| Rock Type |
Broad categorization of rock into one of five types: Plutonic, Volcanic Sedimentary, Metamorphic or Hydrothermal. |
| Rock Desc |
Brief text description of rock lithology. |
| Authors |
Text string with a list of authors in standard reference format. |
| Year |
Year published |
| Title |
Title of paper, book, memoir, map etc. |
| Reference Info |
Journal, book, thesis etc. information, including volume and page numbers if pertinent. |
| Compilation Name |
Title of compilation under which the sample was included. |
