Table: `ndb.geochronology`#

Description#

This table stores geochronologic data. Geochronologic measurements are from geochronologic samples, which are from Analysis Units, which may have a depth and thickness. Geochronologic measurements may be from the same or different Analysis Units as fossils. In the case of faunal excavations, geochronologic samples are typically from the same Analysis Units as the fossils, and there may be multiple geochronologic samples from a single Analysis Unit. In the case of cores used for microfossil analysis, geochronologic samples are often from separate Analysis Units; dated core sections are often thicker than microfossil Analysis Units.

TODO: Expand this description with: - What data does this table store? - What is the business/research purpose? - How is this data collected or generated? - Are there any important caveats or data quality issues?

Table Structure#

Schema: ndb | Table Comment: This table stores geochronologic data. Geochronologic measurements are from geochronologic samples, which are from Analysis Units, which may have a depth and thickness. Geochronologic measurements may be from the same or different Analysis Units as fossils. In the case of faunal excavations, geochronologic samples are typically from the same Analysis Units as the fossils, and there may be multiple geochronologic samples from a single Analysis Unit. In the case of cores used for microfossil analysis, geochronologic samples are often from separate Analysis Units; dated core sections are often thicker than microfossil Analysis Units.

Statistics#

Metric	Value
Row Count	46,891
Total Size	21 MB
Table Size	7016 kB
Indexes Size	15 MB

Relationships#

Primary Key: geochronid

Foreign Keys:

agetypeid → agetypes.agetypeid
geochrontypeid → geochrontypes.geochrontypeid
sampleid → samples.sampleid

Referenced By:

TODO: Document which tables reference this table (will be auto-detected in validation).

Data Dictionary#

Column	Type	Nullable	Default	Constraints	Description
`geochronid`	integer	✗	`nextval('ndb.seq_geochronol...`	PRIMARY KEY	An arbitrary Geochronologic identification number.
`sampleid`	integer	✗	`-`	FOREIGN KEY, UNIQUE	Sample identification number. Field links to Samples table.
`geochrontypeid`	integer	✗	`-`	FOREIGN KEY	Identification number for the type of Geochronologic analysis, e.g. «Carbon-14», «Thermoluminescence». Field links to the GeochronTypes table.
`agetypeid`	integer	✗	`-`	FOREIGN KEY	Identification number for the age units, e.g. «Radiocarbon years BP», «Calibrated radiocarbon years BP».
`age`	double precision	✓	`-`	-	Reported age value of the geochronologic measurement.
`errorolder`	double precision	✓	`-`	-	The older error limit of the age value. For a date reported with ±1 SD or σ, the ErrorOlder and ErrorYounger values are this value.
`erroryounger`	double precision	✓	`-`	-	The younger error limit of the age value.
`infinite`	boolean	✗	`-`	-	Is «True» for and infinite or “greater than” geochronologic measurement, otherwise is «False».
`delta13c`	double precision	✓	`-`	-	The measured or assumed δ13C value for radiocarbon dates, if provided. Radiocarbon dates are assumed to be normalized to δ13C, and if uncorrected and normalized ages are reported, the normalized age should be entered in the database.
`labnumber`	character varying(40)	✓	`-`	UNIQUE	Lab number for the geochronologic measurement.
`materialdated`	character varying(255)	✓	`-`	-	Material analyzed for a geochronologic measurement.
`notes`	text	✓	`-`	-	Free form notes or comments about the geochronologic measurement.
`recdatecreated`	timestamp without time zone	✗	`timezone('UTC'::text, now())`	-
`recdatemodified`	timestamp without time zone	✗	`-`	-

TODO: Review column descriptions and add comments where missing.

Usage Examples#

Example 1: Basic Selection#

-- Get recent records from geochronology
SELECT *
FROM geochronology
ORDER BY geochronid DESC
LIMIT 10;

Purpose: Retrieve the 10 most recent records from geochronology

Example 2: Count Records#

-- Count total records
SELECT COUNT(*) as total_records
FROM geochronology;

Purpose: Get the total number of records in geochronology

Example 3: Filter by Date Range#

-- Get records within a date range
SELECT *
FROM geochronology
WHERE recdatecreated >= '2024-01-01'
  AND recdatecreated < '2025-01-01'
ORDER BY recdatecreated DESC;

Purpose: Retrieve records from geochronology within a specific date range

Example 4: Join with agetypes#

-- Join with related table
SELECT 
    t1.*,
    t2.*
FROM geochronology t1
INNER JOIN agetypes t2 
    ON t1.agetypeid = t2.agetypeid
LIMIT 100;

Purpose: Retrieve geochronology records with related data from agetypes

Example 5: Aggregate Data#

-- Aggregate records by sampleid
SELECT 
    sampleid,
    COUNT(*) as count
FROM geochronology
GROUP BY sampleid
ORDER BY count DESC
LIMIT 10;

Purpose: Count records grouped by sampleid

TODO: Add more specific examples relevant to common research questions or operational tasks.

Data Quality Notes#

TODO: Document: - Known data quality issues - Validation rules - Expected data ranges - Update frequency and mechanisms - Any ETL processes that populate this table

Maintenance#

Data Owner: TODO: Assign owner
Update Frequency: TODO: Document frequency
Last Major Schema Change: TODO: Document when schema last changed

Table: ndb.geochronology#