Chronostratigraphy allows earth scientists to determine the synchronicity of geologic events and the rate at which they occur. It is a fundamental tool when investigating the cause-and-effect relationships of environmental and palaeobiological change. The chronostratigraphic tool kit includes index fossils, stratal boundaries, radiogenic geochronometers, and magnetostratigraphy. Unfortunately, not all rock units contain these common chronostratigraphic markers. This is especially true in many packages of marine and lacustrine mudstone which compose approximately two-thirds of the sedimentary record . One relativity recent advancement is the use of rhenium-osmium geochronology of organic-rich mudstones to directly determine their depositional age.
Re-Os Isotope Geochronology of Organic-rich Mudstones: Development of a New Sampling Strategy to Reduce Age Uncertainty
Pietras, J.T., Dennett, A., Selby, D., and Birdwell, J.E., 2022, The role of organic matter diversity on the Re-Os systematics of organic-rich sedimentary units: Insights into the controls of isochron age determinations from the lacustrine Green River Formation: Chemical Geology, v. 604.
Pietras, J.T., Selby, D., Brembs, R., and Dennett, A., 2020, Tracking drainage basin evolution, continental tectonics, and climate change: Implications from osmium isotopes of lacustrine systems: Palaeogeography, Palaeoclimatology, Palaeoecology, v. 537.