On the 8^th of October 2021, Ellinor Martin successfully defended her doctoral thesis:  The micrometeorite flux to Earth through the Phanerozoic Eon. The Faculty opponent was Professor Timothy Swidle, University of Arizona, USA. The examination committee comprised three persons: Professor Ulf Hålenius, The Swedish Museum of Natural History;  Professor Vivi Vajda, The Swedish Museum of Natural History, and Professor Kristina Stenström, Lund University. Chairman of the event was Professor Knut Deppert, Lund University.

Ellinor has been a great asset for the AGB laboratory and we will miss her. We whish her all the luck in the future. Her impressing thesis comprising nine articles in high ranked journals will undoubtedly be a great stepping stone for the future career!

https://www.pnas.org/content/pnas/118/24/e2020977118.full.pdf

https://advances.sciencemag.org/content/7/9/eabe3647

On the 13^th of December 2019, Samuele Boschi successfully defended his doctoral thesis:  The flux of extraterrestrial spinels to Earth associated with He-3 anomalies in Cenozoic and Ordovician sediments. The Faculty opponent was Professor Luigi Folco, University of Pisa, Italy. The examination committee comprised three persons: Professor Jan Smit, Vrije Universiteit Amsterdam; Associate Professor Davide Lenaz, University of Trieste; and Professor Per Ahlberg, Lund University.

Samuele’s hard and meticulous work for 4 years resulted in a thesis with many peer-reviewed articles in high ranked journals. He is also the first to become a PhD within the field of Astrogeobiology.

Two members of the examination committee and the Faculty opponent at the AGB office. From left to right: Jan Smit (holding a fossil meteorite), Luigi Folco and Davide Lenaz.

Luigi Folco, Jan Smit and Davide Lenaz in the hydrochloric acid laboratory.

Link to article in Science Advances

Link to editorial highlight in Science

An extraterrestrial trigger for the mid-Ordovician ice age: Dust from the breakup of the L-chondrite parent body

Birger Schmitz¹*, Kenneth A. Farley², Steven Goderis³, Philipp R. Heck^4,5, Stig M. Bergström⁶, Samuele Boschi¹, Philippe Claeys⁷, Vinciane Debaille⁸, Andrei Dronov^9,10, Matthias van Ginneken¹¹, David A.T. Harper¹², Faisal Iqbal¹, Johan Friberg¹, Shiyong Liao^13,14, Ellinor Martin¹, Matthias M. M. Meier^15,16, Bernhard Peucker-Ehrenbrink¹⁷, Bastien Soens⁷, Rainer Wieler¹⁵, Fredrik Terfelt¹

¹Astrogeobiology Laboratory, Department of Physics, Lund University, Lund, Sweden.²Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, CA, USA. ³Department of Chemistry, Vrije Universiteit Brussel, Brussels, Belgium.  ⁴Robert A. Pritzker Center for Meteoritics and Polar Studies, The Field Museum of Natural History, Chicago, IL, USA. ⁵Department of the Geophysical Sciences, The University of Chicago, Chicago, IL, USA. ⁶School of Earth Sciences, The Ohio State University, Columbus, OH, USA. ⁷Analytical, Environmental, and Geo-Chemistry, Vrije Universiteit Brussel, Brussels, Belgium. ⁸Laboratoire G-Time, Université Libre de Bruxelles, Brussels, Belgium. ⁹Geological Institute, Russian Academy of Sciences, Moscow, Russia. ¹⁰Institute of Geology and Oil and Gas Technologies, Kazan (Volga Region) Federal University, Kazan, Russia. ¹¹Royal Belgian Institute of Natural Sciences, Brussels, Belgium. ¹²Department of Earth Sciences, Durham University, Durham, UK. ¹³Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing, China. ¹⁴CAS Center for Excellence in Comparative Planetology, Hefei, China. ¹⁵Department of Earth Sciences, ETH Zürich, Zürich, Switzerland. ¹⁶Naturmuseum St. Gallen, St. Gallen, Switzerland. ¹⁷Department of Marine Chemistry and Geochemistry, Woods Hole Oceanographic Institution, Woods Hole, MA, USA.

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.

NASA’s  New Horizons spacecraft passed within 2200 miles of  object 2014 MU69, also called “Ultima Thule”,  in the Kuiper Belt 6.6 billion kilometres from Earth and 1.6 billion kilometres beyond Pluto. Ultima Thule is the most distant object ever studied up-close by humans.

At the NOVA-NASA event in connection with the flyby at New Years Eve Walter Alvarez gave a talk entitled “Studying the Solar System by looking down”.

In February 2017 we published the article Rare Meteorites Common in the Ordovician Period in Nature Astronomy.  This the first empirical reconstruction of variations in the meteorite flux to Earth in deep time. We show that the meteorites falling  on Earth in the Ordovician period one million years before the L-chondrite parent body breakup were very different from todays meteorites.  We show that primitive achondrites that are extremely rare in today’s flux were one of the most common types of Ordovician meteorites. The article was accompanied by a News and Views item “Meteorites: A shift in shooting stars” by Francesca DeMeo at the Massachusetts Institute of Technology, US. Our article received much media attention,  reaching an altmetric value in the top 99th percentile.

The article in Nature Astronomy can be found here 2017-Nature Astronomy.pdf, and the accompanying News and Views item here: DeMeo.pdf.

We just published completed another of our first “windows” into the meteorite flux to Earth in deep time. We extracted and analyzed 108 extraterrestrial spinels from 1652 kg of pelagic limestone from  the Lower Cretaceous Maiolica Formation in the Apennines of Italy.  You find the paper here: 9-2017Schmitz-Geology

In June 2016 we published the paper “A new type of solar-system research recovered from Ordovician limestone” in Nature Communications. This led to an unexpected reaction: Almost every leading daily news paper around the world highlighted the discovery of the world’s first “extinct” meteorite.

According to altmetrics value the article is now ranked as number 181 of the 271,861 tracked articles of a similar age in all journals (Sept. 18, 2017). Among the 759 tracked articles of a similar age published in Nature Communications it is ranked as number 7.

The media frenzy started after BBC wrote about our discovery. Then Nature.com highlighted our discovery at their prime space slot for a couple of days. Discover Magazine ranked our finding among the 100 most important during 2016.

You can find the article in Nature Communications here.

Here are some of the media highlights:

New York Times:

New ‘Extinct’ Meteorite Hints at Violent Cosmic Collision

Washington Post:

https://www.washingtonpost.com/news/speaking-of-science/wp/2016/06/15/ancient-swedish-space-rock-may-be-a-whole-new-kind-of-meteorite/?utm_term=.1f8adda9e967

BBC:

http://www.bbc.com/news/science-environment-36532174#

The Hindu:

http://www.thehindu.com/todays-paper/tp-in-school/unknown-alien-rock-found/article14424213.ece1