U-th/he dating - Problems U-Pb Radioisotope Dating Methods | Answers in Genesis


Apatite is one of a few minerals produced and used by biological micro-environmental systems. Apatite is the defining mineral for 5 on the Mohs scale . Hydroxyapatite, also known as hydroxylapatite, is the major component of tooth enamel and bone mineral . A relatively rare form of apatite in which most of the OH groups are absent and containing many carbonate and acid phosphate substitutions is a large component of bone material.

Zircon is ubiquitous in the crust of Earth. It occurs as a common accessory mineral in igneous rocks (as primary crystallization products), in metamorphic rocks and as detrital grains in sedimentary rocks . [1] Large zircon crystals are rare. Their average size in granite rocks is about – mm, but they can also grow to sizes of several centimeters, especially in mafic pegmatites and carbonatites . [1] Zircon is also very resistant to heat and corrosion.

The decay of 238 U and 235 U to 206 Pb and 207 Pb, respectively, forms the basis for one of the oldest methods of geochronology (Dickin 2005; Faure and Mensing 2005). While the earliest studies focused on uraninite (an uncommon mineral in igneous rocks), there has been intensive and continuous effort over the past five decades in U-Pb dating of more-commonly occurring trace minerals. Zircon (ZrSiO 4 ) in particular has been the focus of thousands of geochronological studies, because of its ubiquity in felsic igneous rocks and its claimed extreme resistance to isotopic resetting (Begemann et al. 2001).


U-th/he dating

U-th/he dating