Scientists Refine Earth's Clock

Reference:
http://www.sciencedaily.com/releases/2012/03/120329141918.htm

Summary:
New research has revealed that some events in Earth's history happened more recently than previously thought. Scientists from the British Geological Survey and the Massachusetts Institute of Technology, publishing recently in the journal Science, have refined the data used to determine how much time has passed since a mineral or rock was formed. They report uranium isotopic composition of minerals, used to date major geological events, which are more accurate than previously published. The major effect of this is to reduce previous age determinations by up to 700,000 years.


Critique:
what geological events have been shown through these mineral rocks?


Impact:
reduce previous age determinations