Discriminating between impact or nonimpact origin of small meteorite crater candidates: No evidence for an impact origin for the Tor crater, Sweden

1Jüri Plado,2,3Ania Losiak,1Argo Jõeleht,4Jens Ormö,5Helena Alexanderson,5Carl Alwmark,6Eva Maria Wild,6Peter Steier,2Marek Awdankiewicz,3Claire Belcher
Meteoritics & Planetary Science (in Press) Link to Article [https://doi.org/10.1111/maps.13914]
1Department of Geology, University of Tartu, Ravila 14A, EE 50411 Tartu, Estonia
2Institute of Geological Sciences, Polish Academy of Sciences, Podwale 75, PL 50-449 Wrocław, Poland
3WildFIRE Lab, University of Exeter, Exeter, EX4 4PS UK
4Centro de Astrobiología CSIC-INTA, Instituto Nacional de Técnica Aeroespacial, 28850 Torrejon de Ardoz, Spain
5Department of Geology, Lund University, SE-22362 Lund, Sweden
6VERA Laboratory, Faculty of Physics, Isotope Physics, University of Vienna, Währinger Straße 17, A-1090 Vienna, Austria
Published by arrangement with Johne Wiley & Sons

Compared to intensive research on km-sized meteorite impact craters, fewer studies focus on smaller craters. The small craters are often hard or impossible to recognize using “classical” criteria like the presence of shatter cones, shocked quartz, and geochemical indicators. Therefore, a long list of candidate structures awaiting approval/disapproval of their origin has been formed over the last decades. One of them is the Tor structure in central Sweden. To test a hypothesis of an impact origin of this structure, we have performed topographical analysis, geophysical studies, 10Be exposure dating of boulders, and 14C dating of Tor-associated charcoal. None of the methods gave us a reason to claim the Tor structure is of impact origin. Thus, we support a recently suggested idea of Tor being formed by a grounded iceberg within a glacial lake.


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