Chemical composition and origin of the shock metamorphic rocks of the Sääksjärvi area, Finland

Papunen, H.

doi:10.17741/bgsf/45.1.004

Cited by 12 publications

(7 citation statements)

References 6 publications

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“…Mostly on the basis of morphological and petrographical features, Lappajarvi (MCCALL, 1968;SVENSSON, 1968aSVENSSON, , 1971LEHTINEN, 1970LEHTINEN, , 1976 and Saaksjarvi (PAPUNEN, 1969(PAPUNEN, , 1973 in Finland, Dellen (SVENSSON, 1968b), Mien (SVENSSON and WICKMAN, 1965;SVENSSON, 1969;STANFORS, 1969), and Hummeln (SVENSSON, 1966) in Sweden, and Lake Kaali in Estonia, USSR (ESKOLA, 1937) were later interpreted as astroblemes rather than extinct volcanos. The diameter of Lake Kaali is only about one hundred meters and it is notable that as early as in 1922 KALJUVEE (1933) recognized it as a meteorite crater.…”

Section: Occurrence Of Astroblemes In Fennoscandiamentioning

confidence: 99%

Major elements and REE in tektites and three probable shock-metamorphic rock series of the Baltic shield.

Koljonen¹,

Rosenberg²

1976

Geochem. J.

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REE contents of four tektites from separate strewn-fields have been determined and the REE and major elements in ten shock-metamorphic rocks from lakes Lappajarvi , Saaksjarvi (Finland), and Tinisjarvi (Soviet Karelia). Neither the impact of meteorite or comet nor secondary weathering seems to change the REE content or distribution pattern in rocks. Therefore, where the texture and major element compo sition in country rock has changed through impact and after it, REE can be used as indicators of the original rock or sediment type. The surfaces of the Moon and each planet, including the earth, probably have unique REE distribution patterns as a result of the prevailing endogenic and exogenic processes . The distribution patterns of REE in tektites, are quite similar to those found in sediments, sedimentary rocks and shock-melted rocks. Accordingly, the origin of tektites from silica-rich clayey sediments or silicic rocks through impact is strongly indicated.

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Section: Occurrence Of Astroblemes In Fennoscandiamentioning

confidence: 99%

Major elements and REE in tektites and three probable shock-metamorphic rock series of the Baltic shield.

Koljonen¹,

Rosenberg²

1976

Geochem. J.

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“…It was later discovered, however, that some agates were embedded in vesicles of impactite-like lava boulders in gravel pits within the Karhiniemi esker at Huittinen (Papunen, 1969). These boulders were tentatively interpreted as impactite rocks by Papunen (1969Papunen ( , 1973. Detailed studies at the Max Planck Institute in Germany verified the impact origin, and an age of 5 14 2 12 Ma (40Ar-39Ar) was obtained for three whole rock melt samples (Muller et al, 1990).…”

Section: The Saaksjarvi Impact Structurementioning

confidence: 99%

“…Detailed studies at the Max Planck Institute in Germany verified the impact origin, and an age of 5 14 2 12 Ma (40Ar-39Ar) was obtained for three whole rock melt samples (Muller et al, 1990). The boulder train of agates and impact melt rocks occurs mainly to the southeast of the lake Saiiksjavi and has been mapped by Papunen (1973), Halme (1974) and Salonen and Aumo (1984). Regional gravity and lowaltitude aerogeophysical measurements over the lake SWsjlrvi site revealed a circular Bouguer anomaly of 4 .…”

mentioning

confidence: 99%

“…Papunen (1969Papunen ( , 1973 classified the boulders into four types: ( I ) impact melt, dark greenish gray, similar to andesite in composition, and small dark green amygdales occasionally filled with silica, (2) vesicular impact melt breccia with crystalline matrix divided to greenish and light brown subtypes, the latter frequently containing agates, (3) impact melt breccia with aphanitic matrix lacking open vesicles, and (4) impact breccia. \duller et al…”

mentioning

confidence: 99%

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Agate as an indicator of impact structures: An example from Sääksjärvi, Finland

Kinnunen

Lindqvist

1998

Meteorit & Planetary Scien

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Abstract-Mineralogical, petrographical and chemical determinations were made for 743 agate (banded variety of chalcedonic quartz) nodules (diameters from 5 mm to 5 cm) formed during postimpact, low-temperature hydrothermal activity as vesicle fillings in the melt rocks of the SZiksjWi meteorite impact structure (diameter 5 km) in southwest Finland. Other hydrothermal vesicle fillings in the impact melt rocks include chlorite, mordenite, smectite and kaolinite. The agates were classified into two types, whose mineralogical properties and chemical compositions fall within the range of volcanic agates (basaltic and rhyolitic host rocks). The relatively high age (-510 Ma) of the StiaksjWi impact melt rocks, however, is reflected by the presence of recrystallization textures, which are rare in younger volcanic agates. The Stitiksjtirvi structure was initially located after following the fortuitous discovery of agate "path-finders" in the glacial overburden. It is recommended that wherever volcanic type agates are found as float in Precambrian shield areas devoid of younger volcanic rocks, the possible presence of impact (or volcanic) craters in the vicinity should be considered.

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“…With regard to the position of point 13 (Palaeogene silty clay), point 16 shifted to the field of the impact glasses of andesitic composition. Papunen (1973) described andesite-like porphyrites from the shock metamorphic rocks of the Lake Saaksjarvi area, Finland, whereas the country rocks there consist only of Precambrian gneisses and migmatites. The "andesites" of this area are chemically intermediate between the country rocks and the impact breccias.…”

Section: Origin and Parent Rock Materials Of Irghizites And Zhamanshinmentioning

confidence: 99%

Irghizites and Zhamanshinites: Zhamanshin Crater, Ussr

et al. 1981

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Two irghizites, three zhamanshinites and one sample each of lechatelierite, vein‐quartz, Palaeogene silty clay and Palaeogene quartzite were analyzed using neutron activation analysis. A silicate analysis of the Palaeogene silty clay has also been performed, as well as an incomplete analysis of the Palaeogene quartzite from the Zhamanshin impact crater. The REE abundances of irghizites resemble those of sedimentary rocks. On the Köhler and Raaz diagram all projection points of irghizites lie inside the field of tektites, and indicate that they were derived from terrestrial sedimentary rocks. The Zhamanshin impact glasses may be divided into three types: (a) silica‐rich zhamanshinites (x̄SiO2 = 73.89%), (b) zhamanshinites (x̄SiO2 = 54.34%), and (c) silica‐poor zhamanshinites (x̄SiO2 = 39.64%). These are also characterized by varying proportions of alkalis and Al. Mn and Ca contents. Irghizites and silica‐rich zhamanshinites display a depletion of Eu. Zhamanshinites do not show this Eu depletion. Partial melting is assumed to be an important process in the origin of zhamanshinites.

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Chemical composition and origin of the shock metamorphic rocks of the Sääksjärvi area, Finland

Cited by 12 publications

References 6 publications

Major elements and REE in tektites and three probable shock-metamorphic rock series of the Baltic shield.

Major elements and REE in tektites and three probable shock-metamorphic rock series of the Baltic shield.

Agate as an indicator of impact structures: An example from Sääksjärvi, Finland

Irghizites and Zhamanshinites: Zhamanshin Crater, Ussr

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