Saarijarvi - Hypervelocity Impact Crater

Alternate Names
Local Language
Coordinates 65° 17' 31" N; 28° 23' 30" E
Notes
  1. Lake, south of Taivakoski, North Finland.
Country Finland
Region Oulu
Date Confirmed 1998
Notes
  1. PDFs in quartz grains from breccias (Pesonen et al., 1998).
Buried? No
Drilled? Yes
Notes
  1. One hole N of central island (Pesonen et al., 1998)
Target Type Crystalline
Notes
  1. Archean granitoids.
Sub-Type Granitoid
Apparent Crater Diameter (km) 2 km
Age (Ma) <600
Notes :
  1. <~520-600 Ma based on stratigraphic age constraints (Ediacaran to Early Cambrian or younger) (Öhman, 2007). Previous work suggests the impact is older than the 600 Ma approximate age of the microfossil acritarchs of the infilled sediments and younger than 2.45 Ga which is the approximate age of the truncated mafic dykes (Pesonen et al., 1998).

Method :
  1. Stratigraphy
Impactor Type Unknown

Advanced Data Fields

Notes

Erosion
7
  1. Heavily eroded by glaciation.
Final Rim Diameter
Unknown
Apparent Rim Diameter
2 km
  1. Presently has an apparent diameter of 1.5-2km (Ohman and Preeden, 2013). Diameter of ~1.5 km (Pesonen et al., 1998).
Rim Reliability Index
2
  1. Structure is mostly filled by a lake and bogs. A small, elongated island is observed in the middle of the lake but this is attributed to tectonic lifting of a block--not central uplift. (Ohman and Preeden, 2013). Note: stratigraphic column in same paper. The units of even closely-spaced drill cores cannot be correlated; they are very chaotic. See p. 961 in (Ohman et al., 2013). Breccias of the northern/central part of the structure largely missing (Ohman, 2007).
Crater Morphology
Simple
Central Uplift Diameter
km
Central Uplift Height
Unknown
Uplift Reliability Index
4
Structural Uplift
Unknown
Thickness of Seds
Target Age
Precambrian
Marine
No
Impactor Type
Other Shock Metamorphism
Maskelynite Kink bands Mosaicism
  1. (Papunen, 1973) Kink bands were found in some biotite grains and mosaicism observed in feldspar (Pesonen et al., 1998)."
Shatter Cones
Yes
  1. Nice photographs in (Ohman and Preeden, 2013). Shatter cones were seen in granitoid boulder and metadiabase outcrop (Ohman and Preeden, 2013).
Planar Fractures
Yes
  1. (Ohman and Preeden, 2013) identify planar fractures in drill core. See Fig. 5.
Planar Deformation Features
Yes
  1. PDF in quartz grains and feldspars (Papunen, 1969). PDFs in quartz grains from the drilled breccia layer (Pesonen et al., 1998).
Diaplectic Glass
No
  1. (Ohman et al., 2013) p968.
Coesite
No
Stisovite
No
Crater Fill
LB, MB
  1. Highly eroded crater. The entire structure has been tectonically tilted, with the southern side lower/better preserved. However, this modification is likely a relatively recent development (Ohman, 2007). No mineral melts or impact melt rocks have been observed (Ohman et al., 2013). A sediment/granitoid breccia dyke injected into basement is observed in a drill core. See fig. 6 in (Ohman et al., 2013).
Proximal Ejecta
Distal Ejecta
Dykes
LB
Volume of Melt
Depth of Melting

References

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L J Pesonen, M Lehtinen, P Tuukki, Andreas Abels (1998) The Lake Saarijarvi: A new meteorite impact structure in northern Finland, 29th Lunar and Planetary Science Conference, p. Abstract 1262, Lunar and Planetary Science Conference, Houston, TX, pdf

L J Pesonen, Andreas Abels, M Lehtinen, P Tuukki (1998) Lake Saarijarvi: A new impact structure in northern Finland, Meteoritics & Planetary Science 33(4, Suppl.), p. A121-A122, Meteoritical Society, Fayetteville, AR, url

Teemu Öhman, Lauri J Pesonen, J Raitala, A Uutela, P Tuisku (2000) The Saarijarvi Crater; older and larger than assumed?, Workshop of the European Science Foundation (ESF) Impact Programme, Juri Plado, Lauri J Pesonen (ed.), p. 82, Geological Survey of Finland, Espoo, url

Teemu Öhman, L J Pesonen, S Elo, A Uutela, P Tuisku, J Raitala (2003) The origin and evolution of the Saarijarvi impact structure, Meteoritics & Planetary Science 38, Suppl., p. 52, Meteoritical Society, Fayetteville, AR, url

Teemu Öhman (2007) The origin and tectonic modification of the Saarijarvi impact structure, northern Finland, Bridging the Gap II: Effect of Target Properties on the Impact Cratering Process 1360, p. 85-86, url

S Staffieri, A Coletta, M L Battagliere, M Virelli (2019) Saarijärvi, Finland, Encyclopedic Atlas of Terrestrial Impact Craters, p. 419-420, Springer, Cham, url, doi:https://doi.org/10.1007/978-3-030-05451-9_112