Congratulations to Samuele Boschi – a successful doctoral thesis defense makes him the first Astrogeobiology PhD!


On the 13th 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.

AGB Laboratory publishes article in Science Advances – highlighted in an editorial in Science

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. Heck4,5, Stig M. Bergström6, Samuele Boschi1, Philippe Claeys7, Vinciane Debaille8, Andrei Dronov9,10, Matthias van Ginneken11, David A.T. Harper12, Faisal Iqbal1, Johan Friberg1, Shiyong Liao13,14, Ellinor Martin1, Matthias M. M. Meier15,16, 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.


AGB Laboratory highlighted at NASA event during Ultima Thule flyby on New Year’s Eve

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”.

Meteorite flux has changed in deep time – First experimental results published in Nature Astronomy

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.

Doing astronomy by “looking down, instead of up”. Fredrik Terfelt collects some of the 270 kg of Ordovician rock from which the micrometeoritic spinels grains for the Nature Astronomy paper were recovered. The Lynna River section in the St. Petersburg region of Russia.

First reconstruction of Mesozoic meteorite flux published in Geology – no signs of a Baptistina asteroid breakup event

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

The crew that did the first pilot sampling in July 2014, Jan Smit, Walter Alvarez, and Birger, Laura and Nelly Schmitz, in front of the micrometeorite-rich bed MMA 36 of the Maiolica Formation. The pilot samples showed that the Maiolica limestone is perfect for our type of work, being extremely pure and very easy to dissolve.
The crew that did the first pilot sampling in July 2014, Jan Smit, Walter Alvarez, and Birger, Laura and Nelly Schmitz, in front of the micrometeorite-rich bed MMA 36 of the Maiolica Formation. The pilot samples showed that the Maiolica limestone is perfect for our type of work, being extremely pure and very easy to dissolve.
Karl Terfelt collects 300 kg of Maiolica limestone bed MMA 335.
Karl Terfelt collects 300 kg of Maiolica limestone bed MMA 335.

Discover Magazine ranks our “extinct” meteorite as one of the 100 most important discoveries in 2016

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 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.

The fossil meteorite Österplana 065 from Ordovician limestone at Kinnekulle. The chromium- and oxygen-isotopic composition of relict spinel grains from the meteorite show that it is a kind of meteorite that is not known among the documented 50,000 meteorites that have fallen on Earth in recent times. Probably the parent-body of Österplana 065 has been consumed in collisions in space, thus there will never fall such a meteorite on Earth again. Hence it is an “extinct” type of meteorite.


Here are some of the media highlights:

New York Times:

New ‘Extinct’ Meteorite Hints at Violent Cosmic Collision

Washington Post:


The Hindu: