Recalibrating the stratigraphic column

Managers of isotopic dating labs may be rubbing their hands with glee.  The absolute dating on which proper correlation of events in Earth’s history depends, is “officially” a dog’s breakfast.  This is partly due to the slowly improving precision and accuracy of radiometric dating applied to ever smaller samples, but also to the high cost of getting the age data.  Many important geological boundaries were dated long ago by methods that would not pass muster today, yet those earlier dates are all that palaeontologists, sedimentologists and palaeoclimate specialists have to go on when estimating rates and correlating events.  Many important stratigraphic and more complex igneous and metamorphic events remain undated, no matter how much their discoverers plead with the isotopic community.  The trend has been to eschew mundane dating in favour of isotopic approaches to petrogenesis, now that really precise data can be had.  Sponsored by a number of geochronological labs in the United States, a meeting in Washington, DC during October 2003 set in motion means to redress the balance.  A proposal is being developed to obtain US$6 million to found three new labs devoted to dating in the USA (plus $2 to 3 million annual operating costs).  The idea is to link similar labs internationally, which would use the same methodology and perform multiple analyses to set standardised dates for important events.  Attendees from other countries will be busy formulating their own proposals at around the same levels, you can be sure.

Source:  Clarke, T. 2003.  Geologists seek to put an end to blind dates.  Nature, v. 425, p. 550-551.

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