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Durham University

Department of Earth Sciences


Publication details for Professor David Harper

Schmitz, Birger, Farley, Kenneth A., Goderis, Steven, Heck, Philipp R., Bergström, Stig M., Boschi, Samuele, Claeys, Philippe, Debaille, Vinciane, Dronov, Andrei, van Ginneken, Matthias, Harper, David A.T., Iqbal, Faisal, Friberg, Johan, Liao, Shiyong, Martin, Ellinor, Meier, Matthias M. M., Peucker-Ehrenbrink, Bernhard, Soens, Bastien, Wieler, Rainer & Terfelt, Fredrik (2019). An extraterrestrial trigger for the mid-Ordovician ice age: Dust from the breakup of the L-chondrite parent body. Science Advances 5(9): eaax4184.

Author(s) from Durham


The breakup of the L-chondrite parent body in the asteroid belt 466 million years (Ma) ago still delivers almost a third of all meteorites falling on Earth. Our new extraterrestrial chromite and 3He data for Ordovician sediments show that the breakup took place just at the onset of a major, eustatic sea level fall previously attributed to an Ordovician ice age. Shortly after the breakup, the flux to Earth of the most fine-grained, extraterrestrial material increased by three to four orders of magnitude. In the present stratosphere, extraterrestrial dust represents 1% of all the dust and has no climatic significance. Extraordinary amounts of dust in the entire inner solar system during >2 Ma following the L-chondrite breakup cooled Earth and triggered Ordovician icehouse conditions, sea level fall, and major faunal turnovers related to the Great Ordovician Biodiversification Event.