Allan Rooney starts off the new Re-Os section with a brief introduction to the method

Sidney Hemming reports on inter-laboratory and inter-method comparison of the Fire Clay tonstein. See her report here.

Learn how to qualify for aliquots of EARTHTIME 205Pb-233U-235U and 202Pb-205Pb-233U-235U tracer solutions. See the U-Pb page.

This paper reports high precision analyses of common U standards which are a big improvement over existing results.

Here are examples of integrating high precision geochronology with astrochronology for the Carboniferous and the Cretaceous.


Ar-Ar pipette blog


U-Pb_Redux 2.7 and Tripoli 4.7



A new EARTHTIME tool is now available for recalculating Ar-Ar dates in light of new decay constants and fluence monitors. Check it out!!

K12 teachers will want to see our new educational module on radioactive decay and isotope dilution

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Synthetic U-Pb solutions for assessing ID-TIMS intra- and inter- laboratory reproducibility are now available.

Tripoli, a powerful new program for viewing, filtering, and interpreting cycle-by-cycle mass spectrometer data, is now available free of charge. For more information, click here.

Data Sucker is also here. Learn about it here.

Meeting Report: Here's a PDF summarizing the recent European EARTHTIME meeting.

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EARTHTIME is an organized, community-based international scientific initiative aimed at sequencing Earth history through the integration of high-precision geochronology and quantitative chronostratigraphy. Our main goal is the development of the geochronological techniques necessary to produce temporal constraints with uncertainties approaching 0.1 percent of the radioisotopic ages.

There are many fundamental problems in Earth's history that can be addressed with a highly-resolved, calibrated time scale because temporal relations are often keys to causality arguments in Earth history, and our understanding of these processes depends on precise knowledge of both dates and rates. For example, a better calibrated time scale will provide insight into biological evolution, adaptive radiations, extinctions and recoveries, climate change, catastrophes, and a better understanding of how Earth as a complete system evolved. Additionally, a deeper appreciation of the importance of geological time and the timescales at which biologic and climatic processes occur is crucial for our continued stewardship of Earth.

In addition to new laboratory and machine procedures, EARTHTIME's goals for improving the precision of uranium-lead geochronology also depend on developing robust software systems for data-handling. The Cyber Infrastructure and Development Lab for the Earth Sciences (CIRDLES.org) is leading this effort on behalf of EARTHTIME. CIRDLES.org develops open source software and provides community forums to support EARTHTIME and EarthChem. The software packages "Tripoli" and "U-Pb_Redux" currently support ID-TIMS. Software support for LA-ICP MS is under development.

EARTHTIME is supported by the National Science Foundation.