3 December 2025

11:45 AM – 12:30 PM

Amphi Grand Kursaal

Apolline Lefort

How are spatial and temporal boundaries defined in geology?Biographical For Apolline Lefort, heritage curator and geologist, the history of the Earth and the Universe that scientists collectively seek to understand and describe is the most beautiful story of all. A naturally tree-like way of thinking and a curiosity deeply rooted in a naturalist education led her to a PhD thesis in integrated stratigraphy, combining geology, paleontology, biology, and chemistry, at the Géoressources laboratory at the University of Lorraine. A globetrotting student (MNHN in Paris, UQAM in Montreal, University of Geneva), teacher, and cultural mediator, between 2012 and 2018 she contributed to a unique research mission on the reconstruction of paleoenvironments from dinosaur trace levels in Switzerland, using Jurassic stratigraphy. The desire to communicate in a different way—through exhibitions, educational tools, and explaining science to all audiences—and a secret passion for natural history collections led her to become director of the Natural History Museum in Besançon. Preserving, studying, promoting, and managing a vast and highly diverse natural history collection, nestled in the heart of the Citadel of Besançon, a UNESCO World Heritage Site, is a daily challenge. Apolline Lefort also participates, as a curator and/or geologist, in various committees and commissions, where she works to highlight and promote collections and natural heritage on a national scale. She is currently campaigning for dialogue between science and the arts to facilitate understanding of contemporary environmental and societal issues, and for museums to remain places of life and sharing, where critical thinking, science, and contemplation come together in harmony.

How are spatial and temporal boundaries defined in geology?

Welcome to Besançon, at the gateway to the Jura Mountains, where the Jurassic period was described and defined! This term, familiar to all, refers to an era in the geological time scale—the international stratigraphic scale—in which millions of years are the unit of measurement. Each period, era, system, or stage that makes up this scale has been defined so that the scientific community can use the same reference points, wherever we are on Earth. The boundaries between these time units are determined by crises (biological, climatic, etc.) and/or sudden events (meteorites, intense volcanic activity, etc.) that have caused a significant and visible change in the succession of sedimentary layers. Each stratum represents a page in a book that makes up the history of the Earth. Since the 17th century, tools have been available to help us navigate sedimentary deposits: a specific temporal vocabulary, stratotype boundaries defined by international commissions, etc., which we will discover together. In the same way, a geological map is a representation of the division of time. The areas delineated on these colorful maps require the expertise of cartographers and geologists, which is being refined by new technological approaches. Whether for knowledge, preservation, exploration, or exploitation, stratigraphy is an essential tool. Not to mention the definition of the “Anthropocene” era, whose boundaries are currently the subject of open debate.