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Tracking Time of the Earth and Solar System

The current estimate of the age of the earth (and the accretion of the other planets) is close to 4,567 million years before present, a value that has been refined progressively since the discovery of radioactivity and its implications to the evolution of the earth. The science (and to some extent art) of geo- and cosmo-chronology underpins this ancient age and involves a huge array of technical and scientific achievements where more precise estimates increasingly depend upon ever more precise measurement of tiny amounts of rare terrestrial and extraterrestrial material. The reliability of the measurements and their evolution of techniques can be traced back to metrology, or the science of measurement. 

Much of what we know about the earth and its evolution is made possible because of geochronology, without which the duration and rate of events cannot be determined with any certainty in the geological record. In fact testing hypotheses regarding the synchronicity of global events (extinctions, rapid climate excursions, etc.) and determining cause and effect (bolide impact leading to extinctions…) is crucially dependent on further refinements of precision and accuracy in geochronology. 

The lecture will wander through earth and cosmic events and highlight some of the more interesting advances in thinking and method that have shaped our view of the antiquity of the earth and its methods of time keeping.


Randy Parrish (BGS)


Randall Parrish has been Professor of Isotope Geology at the University of Leicester and head of the NERC Isotope Geosciences Laboratory at the British Geological Survey since 1996 when he came to the UK from Canada. He has worked in an interdisciplinary environment involving geology, geochronology, isotope geochemistry, and tectonics for the past ~30 years in Canada and the UK and has active research programmes in both laboratory and the field. 

He has published more than 230 research articles and collaborates with many students and colleagues in the UK and internationally. His current research interests involve the tectonics and erosion of the eastern Himalaya in Bhutan, India and China, the influence on global climate of the Late Neogene rise of the Coastal Mountains of Canada and Alaska, the detection and implications to health of depleted uranium used in military theatre, and in innovations in thermal- and plasma ionisation mass spectrometry.