Governance, Contacts and Get Involved

The EARTHTIME Initiative is an international community collaborative effort.  Leadership is currently provided through an ad hoc international steering group who organise workshops, facilitate the working group and help coordinate EARTHTIME activities.

Steering Committee Members

Dan Condon, British Geological Survey, UK

I have been involved with the EARTHTIME Initiative since the 2003 Smithsonian Workshop. Up until 2005 I was a post-doc working as part of the Bowring group at MIT, and then I moved back to the UK (as a NERC Fellow) to work at the NERC Isotope Geosciences Facility at the British Geological Survey and I have not managed to leave yet!

My involvement in EARTHTIME has been focused on the U-Pb calibration efforts, expansion to bring in groups such as the microbeam U-Pb, Re-Os and U-Th isotope dilution communities.  I have also been involved with developing the EARTHTIME programme with colleagues in Europe and in recent years been working with this ad hoc group, organising some workshops to plan the future of this international community endeavour.

I am also interested in the application and specifically the chronology of the stratigraphic record, working on time intervals from the Paleoproterozoic to the Holocene, through a range of collaborative projects.

Email: and Twitter @danjcondon

John Cottle, University of California Santa Barbara, USA

Bio and photo to follow

Rebecca Flowers, University of Colorado Boulder, USA

I was first exposed to EARTHTIME as a PhD student in Sam Bowring’s lab. I subsequently completed a postdoc at Caltech in Ken Farley’s lab where I was trained in the methods, applications, and development of (U-Th)/He geo- and thermochronology. I now run a (U-Th)/He geochronology lab at the University of Colorado Boulder. My group has focused on deciphering the history and causes of unroofing, uplift, and topography in diverse settings, and on the development and refinement of both novel and conventional (U-Th)/He thermochronometers. My lab especially seeks creative, collaborative applications of (U-Th)/He data to problems in fields in which the technique has not typically been utilized (e.g., to constrain lunar impact histories, calibrate mantle dynamic models, date kimberlite emplacement). I also co-lead the AGeS (Awards for Geochronology Student) research program, which is aimed at promoting training and new interactions between students, scientists, and geochronology labs at different institutions. I feel it is important for the future of our science to develop a broad and strong collaborative geochronology community that encompasses producers and users of geochronology data.

Email: Rebecca.Flowers@Colorado.EDU

Sidney Hemming, Lamont-Doherty Earth Observatory, USA

I have been involved with the EARTHTIME Initiative since attending the 2003 Smithsonian Workshop. I am a professor in the Department of Earth and Environmental Sciences at Columbia, and I have been managing the argon geochronology lab at Lamont-Doherty Earth Observatory- part of the Noble Gas Group at Lamont- since 1996.

My involvement in EARTHTIME has been focused on inter-laboratory calibration experiments of solid natural samples as well as the Argon Pipette Intercalibration System (led by Brent Turrin of Rutgers University). The recent acquisition of a new multi collector noble gas mass spectrometer is opening exciting opportunities for measuring smaller samples with higher precision. I hope to continue calibration experiments with my colleagues in U-Pb and Ar-Ar labs and to develop new experiments with scientists using other chronometers.

Many of my research initiatives involve the use the Ar system for sediment provenance, but I am also keenly interested in the chronology of the stratigraphic record throughout Earth history. I am eager to collaborate on a variety of projects in both realms.


Klaudia Kuiper, Vrije Universiteit Amsterdam, Netherlands

My first Earthtime meeting was the October 2004 meeting in Boston and since then I am involved in Earthtime. My PhD and post-doc research focused on integrating astronomical time and radio-isotope (mainly 40Ar/39Ar) time scales and fitted perfectly in the Earthtime theme. I was involved – with many others – in initiating an European Earthtime branch through developing a training network and a networking programme. In my current position as associate professor at the Vrije Universiteit Amsterdam my research still focuses on integration of stratigraphy, sedimentology and geochronology.


Leah Morgan, United States Geological Survey, USA

My first EARTHTIME meeting was the 2008 meeting in Denver, just before finishing my PhD at Berkeley with Paul Renne. I then spent five years as a post-doc in Europe—first with GTSnext at VU Amsterdam with Jan Wijbrans and Klaudia Kuiper, then at SUERC with Darren Mark. Since 2015, I have been in the Argon Geochronology Laboratory at the USGS in Denver.

Since my first meeting, I have participated in many EARTHTIME workshops around the world, including Europe and China, and hosted the 2016 workshop in Denver. I have also focused on measurements of 40Ar abundances and K isotope measurements in mineral standards. At the USGS, I collaborate with the geologic mapping and mineral deposits groups.


Paul Renne, Berkeley Geochronology Centre, USA

 I’ve been involved in EARTHTIME since the watershed 2003 Smithsonian workshop, after which I helped write the NSF proposal that launched the EARTHTIME initiative. EARTHTIME is invaluable for bringing people together to hash out everything from nuts-and-bolts technical issues to strategies for solving diverse problems across the Earth and planetary sciences. Our aim is sharpening the tools of geochronology and bringing these tools to bear effectively and opportunistically on important problems.

My research interests emphasize large igneous provinces, mass extinctions, human evolution, and general chronostratigraphy. For these and other applications I use mainly the 40Ar/39Ar technique and to a lesser extent, paleomagnetism. I’ve been involved in calibrating the 40Ar/39Ar chronometer for many years, and this has come into focus through EARTHTIME. There is still lots to do!


Mark Schmitz, Boise State University, USA

Bio and photo to follow

Blair Schoene, Princeton, USA

I have been involved in EARTHTIME since I was a young graduate student in Sam Bowring’s lab at MIT. I remember fondly being introduced to and impressed by the community of geochronologists that came together for the 2004 meeting in Boston, which shaped the way I do science.  For me, EARTHTIME and geochronology go hand in hand and are the MO of how we do good geochronology.  Upon finishing my PhD at MIT, I went to the University of Geneva to do a postdoc in Urs Schaltegger’s lab and was fortunate not only to be among another fantastic group of geochronologists, but also to help in the launching of the GTSnext project, which was an EARTHTIME inspired multinational grant funded by the European funding agencies.

I have been at Princeton setting up and running a U-Pb ID-TIMS geochronology lab since 2009, where my students, postdocs and I have focused on using accessory mineral U-Pb geochronology to understand magmatic processes and zircon growth in the crust, the rates of flood basalt volcanism, the thermal histories of Archean cratons, the causes and consequences of mass extinction events, and other problems in Earth History such as the enigmatic carbon cycle during the Neoproterozoic and Late Cretaceous climate in Bolivia.  The community of geochronologists participating in EARTHTIME activities, such as data reduction and methods development or making and distributing community standards and tracer solutions, play a crucial role in pushing the science of Geochronology to new levels.  With higher precision and accuracy comes even more interesting questions to be answered, which inspires new types of collaborations daily!


Brad Singer, University of Wisconsin–Madison, USA

Bio and photo to follow

Christian Zeeden, Observatoire de Paris, France

My first Earthtime involvement was as PhD in the GTSnext network. My PhD and recent post-doc research focuses on details of the astronomical time scale ant testing of tuned time scales. In my current position I am working on improving the astronomical time scale in the Cenzoic, and on understanding of uncertainties in astrochronology. Further I am working on integration of different geochronometers and age-depth modelling.

Photo to follow

Working Group ‘Champions’

EARTHTIME has developed a number of thematic working groups that comprises people from multiple laboratories that are working together to further developments in a specific topic area.  Working groups have naturally formed around the different chronometers where the focus is on issues specific to that chronometer, but have also developed to address cross-cutting topics, such as inter-calibration and the development of cyber-infrastructure.

These working groups are ‘bottom up’ entities and are manged by those communities as best suits their needs.

Working Group membership

Get Involved!

We are always seeking additional members to help represent the broader geochronology community, please contact us to get involved.  In particular, representation for the areas of tectonics, astrochronology and thermochronology would be welcomed.  EARTHTIME also needs representation from early career researchers, if you are keen to be involved then please contact a member of the ad hoc steering group