Details

Autor(en) / Beteiligte

• Boehnke, Patrick
• Harrison, T. Mark

Titel

A meta-analysis of geochronologically relevant half-lives: what's the best decay constant?

Ist Teil von

• International geology review, 2014-05, Vol.56 (7), p.905-914

Ort / Verlag

Philadelphia: Taylor & Francis

Erscheinungsjahr

2014

Link zum Volltext

Quelle

Taylor & Francis

Beschreibungen/Notizen

• Twenty-first century advances in both the analytical procedures and instrumentation used in geochronology promise age accuracy better than ±1‰, but realizing this potential requires knowledge of decay constants (λ) that exceed this level. Given the paucity of improved recent measurements of λ, the community has experimented with hybrid methodologies utilizing data largely generated during the 1970s. In this article, we perform a systematic review of laboratory decay constant determinations relevant to geochronology (i.e. 87 Rb, 147 Sm, 176 Lu, 230 Th, 232 Th, 235 U, and 238 U), focusing on methodological consistency. For radioisotopes for which multiple studies are available, results are combined through a random effects model to yield the best available values and associated uncertainties. Unfortunately, despite its vital role in modern geochronology, only one experimental determination of 238 U decay met our criteria for consideration, significantly limiting the ability to assess its reliability. Thus, utilizing λ 238 as an anchor for establishing other decay constants (e.g. 40 K, 176 Lu, and spontaneous 238 U fission) places an unverified result at the core of geochronology. For geochronology to attain its greatest potential, more and better laboratory determinations of decay constants are required, along with a community methodology that permits us to continuously take advantage of new data.