Start Lead isotope analysis dating

Lead isotope analysis dating

1999) 2) using Pb has a half-life of 22.3 years, allowing dating within the past 100 years.

As an example, uranium and thorium concentrate in the liquid phase during melting and crystallization of magma, and are subsequently incorporated into acidic, silica-rich components.

Thus, granites have high uranium and thorium content compared to basaltic rocks.

Three of these isotopes are radiogenic and are produced through the decay of uranium.

Sedimentary and igneous rocks have similar thorium/uranium ratios, but carbonate-rich rocks are strongly enriched in uranium.

Chief among these are: 1) common Pb methods, or single stage models (e.g., Holmes-Houtermans model; see Holmes 1946, Houtermans 1946) for lead minerals that have single-stage histories, i.e., that experienced no lead gain or loss.

Such models plot trajectories of Pb growth after a primeval Pb state from the time of deposition in the earth's crust.

In contrast to the stable isotopes of lead, Lead isotopes are most commonly measured using thermal ionization mass spectrometry (TIMS).