Direct dating of human fossils
Provides information about environmental conditions from variations in ring width.
Matching up distinctive bands from one tree to another allows construction of a master chronology that extends beyond the age of a single tree.
Geosciences /2/04 Direct-dating of fossils Absolute (calendar) age vs relative age Direct dates vs associated dates Methods for direct-dating 1. Dendrochronology and sclerochronology Individual fossils and cross-dating 2.
Radiocarbon dating Radiocarbon incorporated into living material Exponential decay and half-lives Two key assumptions: (1) near-constant production rate and (2) rapid mixing Correcting for the assumptions: (1) tree-ring calibration and (2) reservoir ages Two applications: constructing a sea level curve and dating the Shroud of Turin 3.
Growth rings: in wood (=dendrochronology) or accretionary skeleltons (coral, or mollusks) (=sclerochronology).
Secondly, a combination of Th/U―Pa/U dating could be applied on bones.
The maps show a complex system of U-migration in and out of the dental tissues.
There are clearly domains in the dentine of the tooth where the Th/U ratios indicate continuing U-accumulation.
Here we apply a direct fossil dating, micro-drilling sampling approach that minimises damage to and destruction of precious museum specimens.
We carried out a systematic U–Th dating study (Th-age profiles across three teeth exposed in cross-section, using micro-drilling and thermal ionisation mass spectrometry.