Author name: Mark D. Schmitz

High-precision geochronology is integral to testing hypotheses regarding the correlation, causes, and rates of events and processes in Earth history. Recent studies have sought to reconcile very precise, but apparently conflicting, ages for the same geological samples and events using different chronometers. Both systematic (decay constants, ages of standard materials) and geological (daughter-nuclide loss, inheritance) complexities contribute to the challenges of rock-clock calibration. Community-wide efforts to improve radioisotope geochronology have successfully mitigated many of these factors, and have brought high-precision geochronology to a threshold of unprecedented integration with stratigraphic and geochemical proxies of Earth systems dynamics.

In 1913, Frederick Soddy’s research on the fundamentals of radioactivity led to the discovery of “isotopes.” Later that same year, Arthur Holmes published his now famous book The Age of the Earth, in which he applied this new science of radioactivity to the quantification of geologic time. Combined, these two landmark events did much to establish the field of “isotope geochronology” – the science that underpins our knowledge of the absolute age of most Earth (and extraterrestrial) materials. In celebrating the centenary, this issue brings together modern perspectives on the continually evolving fi eld of isotope geochronology – a discipline that reflects and responds to the demands of studies ranging from the early evolution of the Solar System to our understanding of Quaternary climate change, and the 4.5 billion years in between.