Tiny fossils, tectonics, and the timescale
Abstract
The base of the Cambrian Period (~538 Ma) marks the boundary between the Precambrian and the Phanerozoic. Represented by only a simple (but often debated) line on the timescale, this is one of the most extraordinary transitions in Earth history, marking the change from a microbe-dominated world to a world teeming with complex animal life. Among these animals were some of the first skeleton-bearers; the “small shelly fossils”, and their remains—tiny spines, caps, tubes and plates—are preserved in Cambrian-aged rocks around the globe. Small shelly fossils reveal key evidence for evolutionary relationships between the earliest animals, but they are also important applied tools. In concert with an array of other methods and proxies, small shelly fossil occurrences are essential for dating and correlation, timescale building and refinement, and are increasingly used in palaeobiogeographic and tectonic reconstructions. This talk will be a tour of Cambrian shelly fossil palaeobiology and applications via my work (and that of my students and colleagues) in South Australia, Queensland, Antarctica and Mongolia.
Biography
Dr Marissa Betts is a geologist and palaeontologist at the University of New England in Armidale, working on the Cambrian Period (~538 - 485 million years ago). The early Cambrian "explosion of life" was one of the most important evolutionary events in Earth's history. Her research in Australia, Antarctica, China and Mongolia unearths new fossil species, aims to track how the positions of continents have changed and continues to refine the geological timescale by dating and correlating key packages of rocks around the world. After completing her PhD at Macquarie University in 2016, Marissa came to UNE in 2017 on a Postdoctoral Fellowship and has since transitioned to Senior Lecturer in Earth Science, and is now a DECRA-funded Research Fellow. In 2023, she was appointed as Secretary of the International Subcommission on Cambrian Stratigraphy. She has been awarded the Geological Society of Australia's A.H. Voisey Medal (NSW Division) and Walter Howchin Medal (SA Division), selected as a NSW Young Tall Poppy and an STA Superstar of STEM. In 2022, she directed and produced the award-winning film ROLA[STONE].
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