▁rem an ent ▁magnet ism ▁of ▁each ▁sample . ▁ ▁The ▁results ▁are ▁statist ically ▁processed ▁and ▁an ▁eigen vector ▁is ▁generated ▁that ▁shows ▁the ▁three - dimensional ▁magnetic ▁decl ination ▁that ▁will ▁yield ▁a ▁location ▁for ▁the ▁North ▁P ole ▁at ▁the ▁time ▁of ▁the ▁last ▁thermal ▁event ▁of ▁the ▁feature . ▁ ▁Data ▁from ▁this ▁feature ▁is ▁compared ▁to ▁the ▁regional ▁sec ular ▁variation ▁curve ▁in ▁order ▁to ▁determine ▁the ▁best - fit ▁date ▁range ▁for ▁the ▁feature ' s ▁last ▁firing ▁event . ▁ ▁See ▁also ▁ ▁Mag net ism ▁ ▁Pale om agnet ism ▁ ▁Mag net ic ▁flux ▁ ▁References ▁▁ ▁Arch ae om agnet ic ▁d ating ▁- ▁gu idel ines , ▁English ▁Heritage ▁book let ▁( p .   3 3 ), ▁ 2 0 0 6 ▁ ▁( a ▁popular ▁introduction ▁with ▁illustr ations ▁and ▁references ) ▁ ▁Her ries , ▁A . I . R ., ▁K ov ache va , ▁M ., ▁Kost adin ova , ▁M ., ▁Shaw , ▁J ., ▁ 2 0 0 7 . ▁Arch ae o - direction al ▁and ▁- int ens ity ▁data ▁from ▁bur nt ▁structures ▁at ▁the ▁Th ra cian ▁site ▁of ▁Hal ka ▁Bun ar ▁( B ul g aria ): ▁The ▁effect ▁of ▁magnetic ▁min eral ogy , ▁temperature ▁and ▁atmosphere ▁of ▁he ating ▁in ▁anti qu ity , ▁Physics ▁of ▁the ▁Earth ▁and ▁Planet ary ▁Inter iors . ▁ 1 6 2 , ▁ 1 9 9 – 2 1 6