25983 rows


This table stores Chronology data. A Chronology refers to an explicit chronology assigned to a Collection Unit. A Chronology has Chronology Controls, the actual age-depth control points, which are stored in the ChronControls table. A Chronology is also based on an Age Model, which may be a numerical method that fits a curve to a set of age-depth control points or may simply be individually dated Analysis Units.
A Collection Unit may have more than one Chronology, for example one in radiocarbon years and another in calibrated radiocarbon years. There may be a Chronology developed by the original author and another developed by a later research project. Chronologies may be stored for archival reasons, even though they are now believed to have problems, if they were used for an important research project. One Chronology per Age Type may be designated the default Chronology, which is the Chronology currently preferred by the database stewards.
Based upon the Chronology, which includes the Age Model and the Chron Controls, ages are assigned to individual samples, which are stored in the SampleAges table.
A younger and older age bounds are assigned to the Chronology. Within these bounds the Chronology is regarded as reliable. Ages may be assigned to samples beyond the reliable age bounds, but these are not considered reliable


Column Type Size Nulls Auto Default Children Parents Comments
chronologyid serial 10 nextval('ndb.seq_chronologies_chronologyid'::regclass)
accumulationrates.chronologyid fk_accumulationrates_chronologiesR
chroncontrols.chronologyid fk_chroncontrols_chronologiesC
sampleages.chronologyid fk_sampleages_chronologiesC
collectionunitid int4 10 null
collectionunits.collectionunitid fk_chronologies_collectionunitsC
agetypeid int4 10 null
agetypes.agetypeid fk_chronologies_agetypesC
contactid int4 10 null
contacts.contactid fk_chronologies_contactsR
isdefault bool 1 null
chronologyname varchar 80 null
dateprepared date 13 null
agemodel varchar 80 null
ageboundyounger int4 10 null
ageboundolder int4 10 null
notes text 2147483647 null
recdatecreated timestamp 22 timezone('UTC'::text, now())
recdatemodified timestamp 22 null


Constraint Name Type Sort Column(s)
chronologies_pkey Primary key Asc chronologyid
chroldage_idx Performance Asc ageboundolder
chryoungage_idx Performance Asc ageboundyounger
oldage_idx Performance Asc ageboundolder
youngage_idx Performance Asc ageboundyounger