手法を比較

	ウラン・トリウム年代測定法	Archaeomagnetic Dating
分野	考古学	考古学
系統	Process / pipeline	Process / pipeline
提唱年	1955	1968
提唱者	Harmon Craig	Robert Coe
種類	Decay series dating technique	Magnetic reference frame dating
原典	Edwards, R. L., Chen, J. H., & Wasserburg, G. J. (1987). U-238, U-234 and Th-230 in seawater. Geochimica et Cosmochimica Acta, 51(5), 1213-1225.	Coe, R. S. (1968). The determination of paleointensities and neomagnetic effects on pottery. Journal of Geophysical Research, 73(12), 3247-3262.
別名	U-Th dating, thorium-230 dating	paleomagnetic dating, magnetic declination dating
関連	4	3
概要	Uranium-thorium (U-Th) dating is a chronometric method that determines the age of carbonates, shells, bones, and coral by measuring the ratio of uranium isotopes to thorium-230. First applied by Harmon Craig in the 1950s, it exploits the natural radioactive decay chain of uranium. U-Th dating is particularly valuable for dating materials from 500 to 500,000 years old, filling a crucial chronological gap between radiocarbon and potassium-argon dating.	Archaeomagnetic dating uses changes in Earth's magnetic field intensity and direction recorded in fired clay artifacts to determine age. Pioneered by Robert Coe in the 1960s, the method measures the magnetization of pottery and baked clay features, comparing measurements to a master curve of geomagnetic variation through time. Archaeomagnetic dating is most effective for materials dated to the last 10,000 years and is particularly powerful in arid regions where clay artifacts are well-preserved.