Lumparn - Hypervelocity Impact Crater

Alternate Names N/A
Coordinates 60° 8' 53" N; 20° 7' 40" E
Notes
  1. Bay in island of Åland Archipelago.
Country Finland
Region Southwest Finland
Date Confirmed 1992
Notes
  1. Confirmed by shatter cones found in the southwest shoreline (Svensson, 1993).
Buried? Yes
Notes
  1. Underwater, buried by Pleistocene sediment and Palaeozoic limestone.
Drilled? Yes
Notes
  1. Centre drilled (NRCAN binder).
Target Type Mixed
Notes
  1. Cambrian-Ordovician Rapakivi granite and limestone (Svensson, 1993).
Sub-Type Limestone, Granite
Apparent Crater Diameter (km) 10 km
Age (Ma) ≤458
Notes :
  1. A rough range of ≤458 Ma is recommended based on stratigraphic age constraints (Middle Ordovician, Caradocian, or younger) (Merrill, 1980) (Abels, 2003). Previous work on local stratigraphy suggests an age of 450 ± 10 Ma (Abels et al. 2002). Additional age constraints: Previously dated using stratigraphy as ~1000 Ma Contains only "Baltic limestone" (Ordovician) in the area, (Merrill, 1979).

Method :
  1. Stratigraphy
Impactor Type Unknown

Advanced Data Fields

Notes

Local Language
N/A
Erosion
5
  1. Deeply eroded structure (Svensson, 1993).
Final Rim Diameter
Unknown
Apparent Rim Diameter
10 km
Rim Reliability Index
4
  1. Quite circular at sea level but lower positions in basin are more circular in shape (Merrill, 1980).
Crater Morphology
Complex
Central Uplift Diameter
Unknown
Central Uplift Height
Unknown
Uplift Reliability Index
Unknown
Structural Uplift
Unknown
Thickness of Seds
Unknown
Target Age
Palaeozoic
Marine
No
Impactor Type
Unknown
Other Shock Metamorphism
No
Shatter Cones
Yes
  1. Weakly developed shatter cones have been found along the southwestern shore line of bay (Svensson, 1993) (Svensson, 1994).
Planar Fractures
No
Planar Deformation Features
Yes
  1. (Svensson, 1994)
Diaplectic Glass
No
Coesite
No
Stisovite
No
Crater Fill
LB
  1. Lithic breccias are reported by (Abels et al., 1998), but there is not a thorough description.
Proximal Ejecta
Unknown
Distal Ejecta
Unknown
Dykes
LB, MB?
Volume of Melt
Unknown
Depth of Melting
Unknown

References

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N B Svensson (1993) Lumparn Bay: A meteorite impact crater in the Aland Archipelago, southwest Finland, Meteoritics 28(3), p. 445, Arizona State University, Center for Meteorite Studies, Tempe, AZ, url

F Pipping, V Puura (1996) Impact craters in the surroundings of the Gulf of Finland, Geological Survey of Finland Special Paper 21, p. 127-133, Geologian Tutkimuskeskus, Espoo, url

A Abels, P Mannola, M Lehtinen, L Bergman, L J Pesonen (1998) New observations of the properties of the Lumparn impact structure, Aland islands, southwestern Finland, Meteoritics & Planetary Science 33(4), p. A7-A8

A Abels, L Bergman, M Lehtinen, L J Pesonen (2000) Structural constraints and interpretations on the formation of the Söderfjärden and Lumparn impact structures, Finland, Meteorite Impacts in Precambrian Shields. Programme and Abstracts, the 4th Workshop of the European Science Foundation Impact Programme, J Plado, L J Pesonen (ed.), p. 26-26, Lappajärvi-Karikkoselka-Saaksjärvi: Geological Survey of Finland, pdf