News Release

GSA Today: Putting time in its place

Reports and Proceedings

Geological Society of America

March 2013 <i>GSA Today</i> cover

image: The monument at Klonk, Czech Republic, to the Silurian/Devonian boundary stratotype, which was defined in a section in the adjacent hillside. The people in the photograph formed part of a meeting of the International Commission on Stratigraphy in Prague in 2010. view more 

Credit: GSA Today

Boulder, Colorado, USA – In the March issue of GSA Today, seven scientists from six countries, led by Jan Zalasiewicz of the University of Leicester, propose a realignment of the terms "geochronology" and "chronostratigraphy" in an attempt to resolve the debate of whether units of the Geological Time Scale should have a single (time) or dual (time and time-rock) hierarchy.

In their system, which retains both parallel sets of units, with an option to adopt one or other when appropriate, geochronology refers to all methods of numerical dating and is used to express the timing or age of events in Earth's history and to qualify rock bodies with respect to time intervals. Chronostratigraphy, on the other hand, includes all methods used to establish the relative time relationships of stratigraphic successions and to formally name stratified rock bodies.

In this way, both hierarchies would remain available for use -- geochronologic units continuing as the time units (eons/eras/periods/epochs/ages), while chronostratigraphic units continue as the time-rock units (eonothems/erathems/systems/series/stages).



Chronostratigraphy and geochronology: A proposed realignment

Jan Zalasiewicz et al., Dept. of Geology, University of Leicester, University Road, Leicester LE1 7RH, UK. Pages 4 doi: 10.1130/GSATG160A.1.

GSA Today articles are open access online; for a print copy, please contact Kea Giles. Please discuss articles of interest with the authors before publishing stories on their work, and please make reference to GSA Today in articles published. This press release was written by GSA Today science editor Damian Nance and managing editor Kea Giles.

Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.