View source for Earth:Hummeln structure

{{Infobox terrestrial impact site
| name = Hummeln structure
| other_name = 
| photo = 
| photo_size = 
| photo_alt = 
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| map = Sweden
| map_alt = 
| map_caption = Location of the crater in Sweden
| map_size = 
| location = 
| label =
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| coordinates = {{coord|57|22|N|16|15|E|scale:100000|display=inline,title}}
| coordinates_ref = 
| confidence = Confirmed
| diameter = {{convert|1.2|km|mi|abbr=on}}
| depth = 
| rise =
| imp_size =
| age = 443-470 Ma<br>[[Earth:Ordovician|Ordovician]]
| exposed = Yes
| drilled = No
| bolide = [[Astronomy:Chondrite|Chondrite]]<br>[[Earth:Ordovician meteor event|Ordovician meteor event]]?
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| country = Sweden
| state = 
| province = Småland
| district = 
| municipality = 
}}
The '''Hummeln structure''' was confirmed, in 2015, as an [[Astronomy:Impact crater|impact crater]] in Småland province, Sweden.<ref>{{cite Earth Impact DB | name = Hummeln | accessdate = 2016-05-25}}</ref> It is a {{convert|1.2|km|mi}} wide depression within Lake Hummeln and is estimated to have formed between 470 and 443 [[Megaannum|Ma]] ago, during the [[Earth:Ordovician|Ordovician]]. 

== Description ==
The depression was first described in 1826 but was considered to be the result of volcanism or [[Earth:Tectonics|tectonics]].<ref name=hummeln>L. Ferrière, C. Alwmark, S. Holm-Alwmark, J. Ormö, H. Leroux, and E. Sturkell (2015). [http://www.hou.usra.edu/meetings/lpsc2015/pdf/1758.pdf The Hummeln Structure (Sweden) – Impact Origin Confirmed And Its Link To The L-Chondrite Parent Body Break-Up Event], 46th Lunar and Planetary Science Conference</ref> In the 1960s, mapping of the lake [[Earth:Topography|topography]] gave the first hints of an impact event. More conclusive evidence was found recently when scientists from [[Organization:Lund University|Lund University]], while trying to get to nearby [[Earth:Siljan Ring|Siljan crater]], found [[Chemistry:Shocked quartz|shocked quartz]] around the lake.<ref>Daniel Kelly (2015). [http://www.lakescientist.com/space-rock-created-swedens-hummeln-lake/ Space Rock Created Sweden’s Hummeln Lake], Lake Scientist, Mar 2015.</ref> Further investigation led to more details such as breccia that firmly established the structure's impact nature. 

It has also been suggested that this structure, the nearby [[Earth:Granby crater|Granby crater]], and other coeval small craters in [[Place:Baltoscandia|Baltoscandia]] may be connected to the [[Earth:Ordovician meteor event|Ordovician meteor event]] of 470 Ma.<ref name=hummeln/>

== See also ==
* [[Earth:Ordovician meteor event|Ordovician meteor event]]
* [[Earth:Granby crater|Granby crater]]

== References ==
{{reflist}}

{{Impact cratering on Earth}}

[[Category:Ordovician impact craters]]



{{Sourceattribution|Hummeln structure}}