The astrochronology working group is an informal worldwide collective of people applying astrochronology, developing methods and who have been working together since the start of the EARTHTIME Initiative (ca. 2003) to improve the geological time scale by astronomical calibration of sedimentary successions. This includes paleoclimatic interpretations based on orbitral climate forcing. Below we provide a short summary of the topics being discussed and progressed in astrochronology.
Interested in joining the working group? Email: email@example.com with ‘Astrochronology Working Group’ in the subject line.
[toggle title=”IGCP 652 – Reading time in Paleozoic sedimentary Rock“]
Major events punctuated the Paleozoic: ecological crises and diversifications, shifts in ocean chemistry, climatic changes, etc. One of the key-obstacles in understanding these events lays in the difficulty of providing precise estimates of the duration represented by a sequence of Paleozoic sedimentary rocks. This lack of temporal precision severely hampers the evaluation of forcing mechanisms and rates of climatic, ecological or biogeochemical changes in the Paleozoic. It is therefore essential to first improve the Paleozoic timescale to then unravel the history of the Paleozoic Earth system.
Cyclostratigraphy is a powerful chronometer, based on the detection of the Milankovitch cycles in the sedimentary record. Those cycles result from periodic variations in the Earth-Sun system, affecting the distribution of solar energy over the Planet influencing Earth’s climate on time scales between 104 and 106 years. Through the integration of this astronomical time scale with biostratigraphy and radio-isotopic dating, this project intends to document the environmental evolution during the Paleozoic with a focus on the Ordovician to Devonian (485 – 359 million years). It gathers participants (> 200) from all over the world (36 countries) and promotes the participation of young scientists and scientists from developing countries.
[toggle title=”Cyclostratigraphy intercomparison project“]
A broad range in methodological approaches exists in the field of cyclostratigraphy. However, comparative study between the different approaches is lacking. Different cases demand different approaches, but with the growing importance of the field, questions arise about reproducibility, uncertainties and standardization of results. To satisfy this need in cyclostratigraphy, we initiate a comparable framework for the community. The aims are to investigate and quantify reproducibility of, and uncertainties related to cyclostratigraphic studies and to provide a platform to discuss the merits and pitfalls of different methodologies, and their applicabilities. The intercomparison project will initially be structured around several “test scenarios”, which are signals to be analyzed by participants that feature state-of-the-art challenges in time-series analysis of geologic signals. The aim of the project is not to rank the different methods according to their merits, but to get insight into which specific methods are most suitable for which specific problems, and obtain more information on different sources of uncertainty. As this intercomparison project should be supported by the broader cyclostratigraphic community, we open the floor for suggestions, ideas and practical remarks.
To sign up for the newsletter please contact Matthias.firstname.lastname@example.org
[toggle title=”Astrochron: A Computational Tool for Astrochronology“]
Astrochron is an “open source” computational platform for conducting, and learning about: (1) paleoclimate time series analysis, (2) astronomical time scale construction, and (3) the statistical integration of astrochronologies with other geochronologic/chronostratigraphic data (e.g., radioisotopic geochronology). An ultimate goal of the project is to facilitate efficient and transparent communication of the analytical approaches used, enabling rapid verification of results, while fostering science & methodological innovation through community involvement. Astrochron is written for R, the free software for statistical computing and graphics.
For more information about the Astrochron project, please see: http://www.geology.wisc.edu/~smeyers/software.html
[toggle title=”Key Papers & Software“]
Batenburg, S.J., Gale, A.S., Sprovieri, M., Hilgen, F.J., Thibault, N., Boussaha, M., Orue-Etxebarria, X., 2014. An astronomical time scale for the Maastrichtian based on the Zumaia and Sopelana sections (Basque country, northern Spain). J. Geol. Soc. 171, 165–180. doi:10.1144/jgs2013-015
Batenburg, S.J., Sprovieri, M., Gale, A.S., Hilgen, F.J., Hüsing, S., Laskar, J., Liebrand, D., Lirer, F., Orue-Etxebarria, X., Pelosi, N., Smit, J., 2012. Cyclostratigraphy and astronomical tuning of the Late Maastrichtian at Zumaia (Basque country, Northern Spain). Earth Planet. Sci. Lett. 359–360, 264–278. doi:10.1016/j.epsl.2012.09.054
Hilgen, F.J., Hinnov, L.A., Aziz, H.A., Abels, H.A., Batenburg, S., Bosmans, J.H.C., Boer, B. de, Hüsing, S.K., Kuiper, K.F., Lourens, L.J., Rivera, T., Tuenter, E., Wal, R.S.W.V. de, Wotzlaw, J.-F., Zeeden, C., 2014. Stratigraphic continuity and fragmentary sedimentation: the success of cyclostratigraphy as part of integrated stratigraphy. Geol. Soc. Lond. Spec. Publ. 404, SP404.12. doi:10.1144/SP404.12
Hinnov, L.A., Hilgen, F.J., 2012. Chapter 4 – Cyclostratigraphy and Astrochronology, in: Gradstein, F.M., Ogg, J.G., Schmitz, M.D., Ogg, G.M. (Eds.), The Geologic Time Scale. Elsevier, Boston, pp. 63–83.
Kuiper, K.F., Deino, A., Hilgen, F.J., Krijgsman, W., Renne, P.R., Wijbrans, J.R., 2008. Synchronizing Rock Clocks of Earth History. Science 320, 500–504. doi:10.1126/science.1154339
Liebrand, D., Bakker, A.T.M. de, Beddow, H.M., Wilson, P.A., Bohaty, S.M., Ruessink, G., Pälike, H., Batenburg, S.J., Hilgen, F.J., Hodell, D.A., Huck, C.E., Kroon, D., Raffi, I., Saes, M.J.M., Dijk, A.E. van, Lourens, L.J., 2017. Evolution of the early Antarctic ice ages. Proc. Natl. Acad. Sci. 201615440. doi:10.1073/pnas.1615440114
Liebrand, D., Beddow, H.M., Lourens, L.J., Pälike, H., Raffi, I., Bohaty, S.M., Hilgen, F.J., Saes, M.J.M., Wilson, P.A., van Dijk, A.E., Hodell, D.A., Kroon, D., Huck, C.E., Batenburg, S.J., 2016. Cyclostratigraphy and eccentricity tuning of the early Oligocene through early Miocene (30.1–17.1 Ma): Cibicides mundulus stable oxygen and carbon isotope records from Walvis Ridge Site 1264. Earth Planet. Sci. Lett. 450, 392–405. doi:10.1016/j.epsl.2016.06.007
Meyers, S.R., 2014. astrochron: An R Package for Astrochronology Version 0.6.5.
Meyers, S.R., Siewert, S.E., Singer, B.S., Sageman, B.B., Condon, D.J., Obradovich, J.D., Jicha, B.R., Sawyer, D.A., 2012. Intercalibration of radioisotopic and astrochronologic time scales for the Cenomanian-Turonian boundary interval, Western Interior Basin, USA. Geology 40, 7–10. doi:10.1130/G32261.1
Pälike, H., Hilgen, F., 2008. Rock clock synchronization. Nat. Geosci. 1, 282–282.
Pälike, H., Laskar, J., Shackleton, N.J., 2004. Geologic constraints on the chaotic diffusion of the solar system. Geology 32, 929–932. doi:10.1130/G20750.1
Pälike, H., Norris, R.D., Herrle, J.O., Wilson, P.A., Coxall, H.K., Lear, C.H., Shackleton, N.J., Tripati, A.K., Wade, B.S., 2006. The Heartbeat of the Oligocene Climate System. Science 314, 1894–1898. doi:10.1126/science.1133822
Rivera, T.A., Storey, M., Zeeden, C., Hilgen, F.J., Kuiper, K., 2011. A refined astronomically calibrated 40Ar/39Ar age for Fish Canyon sanidine. Earth Planet. Sci. Lett. 311, 420–426. doi:10.1016/j.epsl.2011.09.017
Zeeden, C., Meyers, S.R., Lourens, L.J., Hilgen, F.J., 2015. Testing astronomically tuned age models. Paleoceanography 30, 369–383.
Zeeden, C., Rivera, T.A., Storey, M., 2014. An astronomical age for the Bishop Tuff and concordance with radioisotopic dates. Geophys. Res. Lett. 41, 2014GL059899. doi:10.1002/2014GL059899