In the past year, EARTHTIME project, funded by NSF, has made significant strides towards uniting the geochronological communities and working towards a common goal of establishing a record of earth history of high temporal precision. There is great potential for the application of these techniques to determining accurate and precise absolute ages, thus yielding previously unattainable insights into rates of geological processes, biological evolution, climate change, and ocean circulation patterns. Modern laboratories can now determine both 40Ar/39Ar and U-Pb dates to better than 0.1% precision. However, given the significantly improved analysis, interlaboratory and inter-decay-scheme differences are now clearly apparent, in some cases being more than 1%, e.g., several million years in the mid-Paleozoic. These discrepancies can lead to major uncertainties when comparing dates obtained using the two systems, which in turn can lead to incorrect geological inferences, for example the potential linking of extinction events with geological events or bolide impacts. The EARTHTIME project is currently organizing the geochronological community to eliminate interlaboratory bias and reduce systematic errors by: 1) developing a standardized set of analytical protocols; and 2) establishing a widely agreed upon set of mineral and isotopic standards for interlaboratory comparison; such an approach will permit the full evaluation of interdecay-scheme bias and allow for the confident integration of U-Pb and 40Ar/39Ar geochronology applied to the calibration of the geological timescale. The current workshop will bring together noted scientists in this area: 1) To evaluate how evolutionary rates vary through time, in different systems (e.g., terrestrial versus marine) and in different clades. 2) To determine the rates of change associated with major climatic events and perturbations to global geochemical cycles in deep time. 3) To determine whether cyclical patterns in deep time are controlled by astronomical cycles; whether the forcing cycles can be identified; and how astronomically controlled cyclostratigraphy can be integrated with other techniques to improve the temporal resolution of the geologic time scale. 4) To improve the calibration of the magnetostratigraphic and chemostratigraphic records. 5) To explore new methods of integrating geochronology and biostratigraphy. This proposal has broad implications for the international Earth Sciences community. Geological time is central to our science and we now have the capability to examine major periods of earth history with unprecedented resolution.
