Siljan - Hypervelocity Impact Crater

Alternate Names Siljan Ring
Coordinates 61° 2' 18" N; 14° 56' 18" E
Notes
  1. The Siljan Ring, about 210 km NW of Stockholm, in central Sweden, is Europe's largest impact crater.
Country Sweden
Region Kopparberg
Date Confirmed 1971
Notes
  1. PDFs identified in quartz (Svensson, 1971). Shatter cones discovered in 1973 (Svensson, 1973).
Buried? No
Drilled? Yes
Notes
  1. Seven boreholes to a depth of between 100 and 700 m penetrated the fractured central uplift. A deep drill hole Graveberg) was at a depth of ~6.6 km in 1990 in the central granite as part of an abiogenic gas search (see Boden and Eriksson, 1988).
Target Type Mixed
Notes
  1. Proterozoic granites and volcanic rocks and Ordovician-Silurian sandstones, shales and limestones (Vlierboom et al., 1985). Debate exists as to how thick the sedimentary cover atop crystalline basement was. E.g.: (Tullborg et al., 1995) vs. (Hendriks and Redfield, 2005). Best-fit modelling by (Holm-Alwmark et al., 2017) suggests ~3km.
Sub-Type Carbonate, Limestone, Mudstone, Sandstone, Volcanics, Granite
Apparent Crater Diameter (km) 75 km
Age (Ma) 380.9 ± 4.6
Notes :
  1. 380.9 ± 4.6 Ma determined by 40Ar/39Ar of impact melt rocks (Jourdan and Reimold, 2012). Additional age constraints: 376.0 ± 1.7 Ma determined by 40Ar/39Ar (Reimold et al. 2004). 368.0 ± 1.1 Ma by 40Ar/39Ar of two different samples of melt yielded two plateau ages (Bottomley et al., 1990).

Method :
  1. 40Ar/39Ar
Impactor Type Unknown
Notes
  1. Modelling by (Holm-Alwmark et al., 2017) suggests a 5km-diameter impactor.

Advanced Data Fields

Notes

Local Language
N/A
Erosion
7
  1. The original topographic relief has been removed by erosion and the sub-structure of the crater floor is exposed. Approximately 1.0 km or erosion has occurred (Grieve, 1988). (Holm-Alwmark et al., 2017) estimated 4 km of erosion for the central part of the structure, and ~4.5 km for the rim area
Final Rim Diameter
65 km
Apparent Rim Diameter
75 km
  1. Rim to rim diameter of 65 km (Holm-Alwmark et al., 2017). On the basis of a new relationship to derive the apparent diameter using maximum shatter cone extent, the apparent diameter is ~75 km (Osinski and Ferriere, 2016). Previous apparent diameter was 52 km.
Rim Reliability Index
1
  1. Consists of a 32 km diameter central core of Dala granites surrounded by a 45 km diameter annular depression, which is partially filled with lakes and contains downfaulted Ordovician and Silurian sediments (Grieve, 1988). SU cannot be estimated due to crystalline rocks in the core of the central uplift.
Crater Morphology
Complex
Central Uplift Diameter
22 km
Central Uplift Height
Unknown
Uplift Reliability Index
4
Structural Uplift
Unknown
Thickness of Seds
~3
Target Age
Precambrian Palaeozoic
Marine
No
Impactor Type
Unknown
  1. Modelling by (Holm-Alwmark et al., 2017) suggests a 5km-diameter impactor.
Other Shock Metamorphism
Shock-twinned zircon and shock-twinned magnetite
  1. Shocked zircon and shocked magnetite reported in shocked granite by Holm-Alwmark et al. (2021).
Shatter Cones
Yes
  1. Shatter cones were first found in 1970 by N.B. Svensson at outcrops along road. Shatter cones, poorly-developed (rarely well-developed), occur in fine- to medium-grained granite and in fine-grained diabasic rocks, from less than 1 cm to as much as 10-12 cm in length (Svensson, 1973). A nice shatter cone in coarse-grained granite is shown in (Thorslund and Auton, 1974). Apical angles varies but is close to 90° (Svensson, 1973). Shatter cones are restricted to a circle with a diameter of ~10 km (based on the map in (Svensson, 1973)). [Occurrence of shatter cones up to 17.2 km from the centre according to (Holm, 2011)]. Whole or partial shatter cones are usually a few tens of centimeters to a meter or two in length, and are covered with horsetail arrangements of striae (Komor et al., 1988). Shatter cones have been registered all over the central part of the structure (Collini, 1988). Apical angles from 70 to 91° (Wickman, 1980). (Wickman, 1980) used shatter cones to determine the impact centre of the structure.
Planar Fractures
No
Planar Deformation Features
Yes
  1. PDF in quartz grains (Svensson, 1971) (Ramseyer et al., 1992).
Diaplectic Glass
Yes
  1. In a few places (and in partial grains only), transformation of quartz, and to an even lesser degree, feldspar, into diaplectic glass is noted" (Reimold, 2015).
Coesite
No
Stisovite
No
  1. No optical microscopic indication for presence of high-pressure phases like coesite or stishovite (Reimold, 2015).
Crater Fill
Unknown
  1. The structure has been eroded below the crater floor. Crater-fill impactites are not preserved (Reimold et al., 2015). (Reimold et al., 2005) dated clast-bearing melt rock dykes. Pseudotachylite also reported by (Reimold et al., 2015).
Proximal Ejecta
Unknown
Distal Ejecta
Unknown
Dykes
M, LB, P
Volume of Melt
Unknown
Depth of Melting
Unknown

References

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N B Svensson (1971) Probable meteorite impact crater in Central Sweden, Nature Physical Science 229, p. 90-92, url

N B Svensson (1973) Shatter cones from the Siljan structure, Central Sweden, Geologiska Föreningen i Stockholm Förhandlinger 95(1), p. 139-143, url

F E Wickman (1980) The impact center of the Siljan Structure, central Sweden, Geologiska Foreningens i Stockholm Forhandlingar 102(2), p. 105-109, Geological Society of Sweden, Stockholm, url

Å Johansson (1984) Geochemical studies on the Boda Pb-Zn deposit in the Siljan astrobleme, central Sweden, Geologiska Föreningen i Stockholm Förhandlingar 106(1), p. 15-25, url, doi:10.1080/11035898409454598

G Berg, B Bollmark (1985) Retention of U and Pb in zircons from shocked granite in the Siljan impact structure, Sweden, Earth and Planetary Science Letters 74(4), p. 347-349, url, doi:10.1016/S0012-821X(85)80006-6

F W Vlierboom, B Collini, J E Zumberge (1986) The occurrence of petroleum in sedimentary rocks of the meteor impact crater at Lake Siljan, Sweden, Organic Geochemistry 10(1-3), p. 153-161, url, doi:10.1016/0146-6380(86)90019-7

A K Gibbs (1986) What will the deep drilling At Siljan, Sweden, prove?, Journal of Petroleum Geology 9, p. 477-478, url, doi:10.1306/BF9AB66C-0EB6-11D7-8643000102C1865D

C Juhlin, L B Pedersen (1987) Reflection seismic investigations of the Siljan impact structure, Sweden, Journal of Geophysical Research: Solid Earth 92(B13), p. 14113-14122, American Geophysical Union, Washington, DC, url, doi:http://dx.doi.org/10.1029/JB092iB13p14113

A A Aldahan, S Morad, B Collini (1987) Clouded, untwinned albite in the Siljan Granite, central Sweden, Neues Jahrbuch fuer Mineralogie. Monatshefte 1987(7), p. 327-335, E. Schweizerbart'sche Verlagsbuchhandlung, Stuttgart, url

C Juhlin, L B Pedersen, P Zhang (1987) Geophysical investigations of the Siljan impact structure, Geoexploration 24(3), p. 261, url, doi:10.1016/0016-7142(87)90046-9

J R Castano, A W A Jeffrey, I R Kaplan, D Karlsson, T Laier, M Schmitt (1988) Geochemical investigations for deep gas drilling in Sijian impact structure, Sweden, AAPG Bulletin 72(2), p. 169, American Association of Petroleum Geologists, Tulsa, OK, url

C Juhlin, G Rissler-Akesson (1988) Relationship between surface and borehole geophysics during deep gas drilling in Siljan impact structures, AAPG Bulletin 72(2), p. 203, American Association of Petroleum Geologists, Tulsa, OK

J R Castano, R M Sneider, G W Bolger (1988) Characterization of lithology and reservoir rock for deep gas drilling in Siljan impact structure, Sweden, AAPG Bulletin 72(2), p. 169-170, American Association of Petroleum Geologists, Tulsa, OK, url

S C Komor, J W Valley, P Brown (1988) Fluid-inclusion evidence for impact heating at the Siljan Ring, Sweden, Geology 16(8), p. 711-715, Geological Society of America (GSA), Boulder, CO, url, doi:http://dx.doi.org/10.1130/0091-7613(1988)016<0711:FIEFIH>2.3.CO;2

P Zhang, T M Rasmussen, L B Pedersen (1988) Electric resistivity structure of the Siljan impact region, Journal of Geophysical Research 93(B6), p. 6485-6501, American Geophysical Union, Washington, DC, url, doi:http://dx.doi.org/10.1029/JB093iB06p06485

A W A Jeffrey, I R Kaplan (1988) Hydrocarbons and inorganic gases in the Gravberg-1 well, Siljan Ring, Sweden, Chemical Geology 71(1-3), p. 237-255, url, doi:10.1016/0009-2541(88)90118-0

D R Hilton, H Craig (1989) The Siljan Deep Well: Helium isotope results, Geochimica et Cosmochimica Acta 53(12), p. 3311-3316, url, doi:10.1016/0016-7037(89)90110-5

G Aberg, B Collini, B Schmitz (1989) K-Ar isotope analyses from the Siljan ring meteorite impact structure, Sweden, Geologiska Foreningens i Stockholm Forhandlingar 111(4), p. 355-360, Geological Society of Sweden, Stockholm, url

S Morad, A Fillipidis, A A Aldahan (1989) Stellerite and Sr‐containing stilbite in granitic rocks from the Siljan Ring structure, central Sweden, Bulletin of the Geological Institutions of the University of Uppsala 12, p. 143-149, url

R A Kerr (1990) Is the Siljan hole completely dry?, Science 247(4947), p. 1178, American Association for the Advancement of Science, Washington, DC, url

S C Komor, J W Valley (1990) Deep drilling at the Siljan Ring impact structure: oxygen-isotope geochemistry of granite, Contributions to Mineralogy and Petrology 105(5), p. 516-532, url, doi:10.1007/BF00302492

L B Pedersen, T M Rasmussen (1990) The gradient tensor of potential field anomalies; some implications on data collection and data processing of maps, Geophysics 55(12), p. 1558-1566, Society of Exploration Geophysicists, Tulsa, OK, ps, doi:http://dx.doi.org/10.1190/1.1442807

C Juhlin (1990) Interpretation of the reflections in the Siljan Ring area based on results from the Gravberg-1 borehole, Tectonophysics 173(1-4), p. 345-360, url, doi:10.1016/0040-1951(90)90229-2

A A AlDahan (1990) Alteration and mass transfer in cataclasites and mylonites in 6.6 km of granitic crust at the Siljan impact structure, central Sweden, Contributions to Mineralogy and Petrology 105(6), p. 662-676, url, doi:10.1007/BF00306532

S Å Elming, G Bylund (1991) Palaeomagnetism and the Siljan impact structure, central Sweden, Geophysical Journal International 105(3), p. 757-770, doi:10.1080/11035899209453472

L B Pedersen, C Juhlin, T M Rasmussen (1992) Electric resistivity in the Gravberg-1 deep well, Sweden, Journal of Geophysical Research 97(B6), p. 9171-9182, American Geophysical Union, Washington, DC, url, doi:http://dx.doi.org/10.1029/91JB02991

K Ramseyer, A A Al Dahan, B Collini, O Landstrom (1992) Petrological modifications in granitic rocks from the Siljan impact structure; evidence from cathodoluminescence, Tectonophysics 216(1-2), L J Pesonen, H Henkel (ed.), p. 195-204, Elsevier, Amsterdam, url

F E Wickman (1994) The Siljan Ring impact structure; possible connections with minor ores in its neighborhood, GFF 116, Part, p. 145-146, Geological Society of Sweden, Stockholm, url

N Papasikas, C Juhlin (1997) Interpretation of reflections from the central part of the Siljan Ring impact structure based on results from the Stenberg-1 borehole, Tectonophysics 269(3-4), p. 237-245, url, doi:10.1016/S0040-1951(96)00167-9

N Juhojuntti, C Juhlin (1998) Seismic lower crustal reflectivity and signal penetration in the Siljan Ring area, Central Sweden, Tectonophysics 288(1-4), p. 17-30, url, doi:10.1016/S0040-1951(97)00279-5

G R McGhee (2001) The 'multiple impacts hypothesis' for mass extinction: A comparison of the Late Devonian and the late Eocene, Palaeogeography, Palaeoclimatology, Palaeoecology 176(1-4), p. 47-58, url, doi:10.1016/S0031-0182(01)00325-X

T Hode, I Dalwigk, C Broman (2003) A hydrothermal system associated with the Siljan impact structure, Sweden - implications for the search of fossil life on Mars, Astrobiology 3(2), p. 271-289, url

Björn Bergman, Ari Tryggvason, Christopher Juhlin (2004) High-resolution seismic traveltime tomography incorporating static corrections applied to a till-covered bedrock environment, Geophysics 69(4), p. 1082, url, doi:10.1190/1.1778250

W U Reimold, S P Kelley, S C Sherlock, H Henkel, C Koeberl (2005) Laser argon dating of melt breccias from the Siljan impact structure, Sweden: Implications for a possible relationship to Late Devonian extinction events, Meteorics & Planetary Science 40(4), p. 591-607, url, doi:10.1111/j.1945-5100.2005.tb00965.x

H Henkel, S Aaro (2005) Geophysical investigations of the Siljan impact structure - A short review, Impact Tectonics, H Koeberl, C and Henkel (ed.), p. 247-283, HEIDELBERGER PLATZ 3, D-14197 BERLIN, GERMANY: SPRINGER-VERLAG BERLIN, doi:10.1007/3-540-27548-7_9

J I Rodríguez-Tablante, C Juhlin, B Bergman (2006) First Arrival Seismic Tomography (FAST) vs. PStomo_eq applied to crooked line seismic data from the Siljan ring area, Computers and Geosciences 32(4), p. 497-511, url, doi:10.1016/j.cageo.2005.08.005

H Stein, G Yang, A Zimmerman, J L Hannah, S Egenhoff (2009) Re-Os fractionation from instantaneous maturation from the Siljan impact site, central Sweden, Annual Meeting - American Association of Petroleum Geologists 2009, American Association of Petroleum Geologists and Society for Sedimentary Geology, Tulsa, OK, url

F Jourdan, W U Reimold (2012) Age of the Siljan impact structure, Meteoritics & Planetary Science 47(1, SI), p. A217, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA: WILEY-BLACKWELL

O Lehnert, G Meinhold, S M Bergström, M Calner, J O R Ebbestad, S Egenhoff (2012) The Siljan Ring in central Sweden - a window into the Palaeozoic history of Baltoscandia, Geophysical Research Abstracts 14, p. 11247

O Lehnert, G Meinhold, S M Bergström, M Calner, J O R Ebbestad, S Egenhoff, Å M Frisk, J L Hannah, A E S Hogstrom, W D Huff, C Juhlin, J Maletz, H J Stein, E Sturkell, T R A Vandenbroucke (2012) New Ordovician-Silurian drill cores from the Siljan impact structure in central Sweden; an integral part of the Swedish Deep Drilling Program, GFF 134(2), p. 87-98, Geological Society of Sweden, Stockholm, url, doi:http://dx.doi.org/10.1080/11035897.2012.692707

C Juhlin, E Sturkell, J O R Ebbestad, O Lehnert, A E S Högström, G Meinhold (2012) A new interpretation of the sedimentary cover in the western Siljan Ring area, central Sweden, based on seismic data, Tectonophysics 580, p. 88-99, Elsevier B.V., url, doi:10.1016/j.tecto.2012.08.040

S Holm, L Ferrière, C Alwmark (2012) A statistical study of shocked quartz grains from the Siljan umpact structure (Sweden)- horizontal versus vertical C-axes, 43rd Lunar and Planetary Science Conference, p. 43-44, pdf

O Lehnert, G Meinhold, A Arslan, J O R Ebbestad, M Calner (2013) Ordovician stratigraphy of the Stumsnäs 1 drill core from the southern part of the Siljan Ring, central Sweden, GFF 135(2), p. 204-212, url, doi:10.1080/11035897.2013.813582

A Arslan, G Meinhold, O Lehnert (2013) Ordovician sediments sandwiched between Proterozoic basement slivers: tectonic structures in the Stumsnäs 1 drill core from the Siljan Ring, central Sweden, Gff 135(2), p. 213-227, url, doi:10.1080/11035897.2013.809016

Manzur Ahmed, O Lehnert, D Fuentes, G Meinhold (2014) Origin of oil and bitumen in the Late Devonian Siljan impact structure, central Sweden, Organic Geochemistry 68, p. 13-26, Elsevier Ltd, url, doi:10.1016/j.orggeochem.2013.12.010

F E Wickman (2015) Displacements and the Siljan ring structure, Geografiska Annaler: Series A, Physical Geography 63(3), p. 313-317

W U Reimold, L Fischer, J Müller, T Kenkmann, R T Schmitt, U Altenberger, A Kowitz (2015) Impact-generated pseudotachylitic breccia in drill core BH-5 Hättberg, Siljan impact structure, Sweden, GFF 137(2), p. 141-162, url, doi:10.1080/11035897.2015.1015264

H Muhamad, C Juhlin, O Lehnert, G Meinhold, M Andersson, M G Juanatey, A Malehmir (2015) Analysis of borehole geophysical data from the Mora area of the Siljan Ring impact structure, central Sweden, Journal of Applied Geophysics 115, p. 183-196, Elsevier B.V., url, doi:10.1016/j.jappgeo.2015.02.019

S Holm-Alwmark, A S P Rae, Ludovic Ferrière, Carl Alwmark, G S Collins (2017) Combining shock barometry with numerical modeling: Insights into complex crater formation—The example of the Siljan impact structure (Sweden), Meteoritics & Planetary Science 52(12), p. 2521-2549, University of Arkansas, url, doi:10.1111/maps.12955

Y I Pikovsky, M P Glasko, V G Kutcherov (2017) The block structure and the presense of oil and gas in the Siljan impact crater, Russian Geology and Geophysics 58(2), p. 199-205, url

H Muhamad (2017) Geophysical studies in the western part of the Siljan Ring Impact Crater, url

H Muhamad, C Juhlin, A Malehmir, D Sopher (2018) Integrated interpretation of geophysical data of the Paleozoic structure in the northwestern part of the Siljan Ring impact crater, central Sweden, Journal of Applied Geophysics 148, p. 201-215, url

H Drake, N M W Roberts, C Heim, M J Whitehouse, S Siljeström, E Kooijman, Curt Broman, M Ivarsson, M E Åström (2019) Timing and origin of natural gas accumulation in the Siljan impact structure, Sweden, Nature Communications 10, p. 4736, url

Y I Pikovsky, N I Khlynina, V G Kutcherov (2021) Polycyclic Aromatic Hydrocarbons in Rocks and Soils of the Siljan Impact Crater, Sweden, Lithology and Mineral Resources 56, p. 236-247, url

H Drake, M Ivarsson, C Heim, O Snoeyenbos-West, S Bengtson, V Belivanova, M J Whitehouse (2021) Fossilized anaerobic and possibly methanogenesis-fueling fungi identified deep within the Siljan impact structure, Sweden, Communications Earth & Environment 2(1), p. 1-10, url