Abstract

Telling time in sedimentary successions allows us to understand rates of change in sedimentary systems, connect cause and effect in Earth’s complex and co-evolving systems, and place sedimentary records into broader global contexts. An absolute temporal framework for sediments is very useful but often elusive in ancient rocks, especially those without clear biostratigraphy. The Ediacaran Period, an interval of Earth history which saw major geochemical perturbations, climatic change, and the early diversification of animals, can help us understand the co-evolution of Earth and life. Yet telling time in Ediacaran strata is not always straightforward, and temporal challenges have prevented us from a fuller understanding of the period. I present new radiometric age constraints using the Re-Os geochronometer from the Huqf Supergroup of Oman which pin its rich sedimentological and geochemical records in time and define a temporal framework for the period. These constraints elucidate the timing and synchroneity of Earth’s largest negative carbon isotope excursion, the Shuram. I also leverage these results to test the chronostratigraphic potential of sedimentary carbonates from Oman using the U-Pb system and laser ablation ICP -MS. I present some of my recent work from other field areas exploring this rapidly developing technique.