Meteorite crater re-interpreted as iceberg pit in west-central Sweden

• This study shows the occurrence of numerous iceberg imprints on the bottom of former ice-dammed lakes in Harjedalen, west-central Sweden. Discussion of the genesis of the so-called "impact crater" known as the Tor structure at Torbygget, which is located in this area, motivated an examination of the area using high-resolution digital elevation models. Previous investigations have suggested that this crater was created by a meteorite impact about 2000 years ago, forming a semi-round depression. The results of our investigation clearly indicate that the feature was formed by a grounding iceberg, scouring the bed of an ice-dammed lake during deglaciation about 11 000-10 000 cal. BP. Geomorphic evidence of an ice-dammed lake (multiple and abundant well-developed shorelines) are consistent with earlier mapping efforts in the area. Furthermore, an abundance of geomorphological traces of iceberg activity is found within the paleo-ice-dammed lake basins. Based on this we suggest that the depression at Torbygget is not an impact crater but formed by a grounded iceberg.

Ämnesord

NATURVETENSKAP  -- Geovetenskap och miljövetenskap (hsv//swe)

NATURAL SCIENCES  -- Earth and Related Environmental Sciences (hsv//eng)

Nyckelord

Deglaciation

ice-dammed lake

iceberg

impact crater

Ljusnan Ice Lake

Torbygget

impact

marks

erosion

Geology

Paleontology

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