RESEARCH PAPER
New K-Ar Cooling Ages of Granitoids from the Strzegom-Sobótka Massif, SW Poland
 
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1
Institute of Geological Sciences, Wrocław University, M. Borna 9, 50-205 Wrocław
 
2
Institute of Physics, Maria Curie-Sklodowska University, Plac Marii Curie-Skłodowskiej 1, 20-031 Lublin, Poland
 
 
Online publication date: 2007-07-04
 
 
Publication date: 2007-07-01
 
 
Geochronometria 2007;27:5-9
 
KEYWORDS
ABSTRACT
The Strzegom-Sobótka Variscan Massif (Fore-Sudetic Block, NE Bohemian Massif) consists of various post-kinematic Variscan granitoids emplaced into Palaeozoic low grade metamorphic rocks. Biotite from five samples representing the hornblende-biotite monzogranite, biotite monzogranite and biotite granodiorite has been dated using the K-Ar method for two size-fractions (0.25-0.35 and 0.35-0.5 mm). Finer fractions show more intense chloritization and therefore the results for them were rejected in further discussion. Coarser fractions with higher potassium content were accepted as yielding a maximum estimate approaching the true K-Ar biotite cooling ages. The results are clustered in two groups. The older age group (308.8±4.6 Ma and 305.5±4.3 Ma) comprises results obtained from the biotite granodiorites. They are generally consistent with the zircon crystallization age of 308.4±1.7 Ma reported by Turniak et al. (2005) and imply rapid cooling of the biotite granodiorite from magmatic temperatures down to the closure temperature of K-Ar isotopic system in biotite. The younger group is defined by 291.0±4.4 Ma and 298.7±5.2 Ma ages for the hornblende-biotite monzogranite and 294.2±4.3 Ma age for the biotite monzogranite. In the absence of precise U-Pb or Pb-Pb zircon data further geochronological studies are needed to decipher precisely the cooling history of the monzogranites.
 
REFERENCES (23)
1.
Borucki J, 1966. Wstępne wyniki datowań bezwzględnych (K-Ar) granitoidów dolnośląskich (Preliminary results of K-Ar dating of the Lower Silesia granitoids). Kwartalnik Geologiczny 10: 1-18 (in Polish).
 
2.
Depciuch T, 1971. Wiek bezwzględny granitoidów strzegomskich określony metodą K-Ar (Absolute age of Strzegom granitoids determined by K-Ar method). Kwartalnik Geologiczny 15: 862-869 (in Polish).
 
3.
Di Vincenzo G, Viti C and Rocchi S, 2003. The effect of chlorite interlayering on 40Ar-39 Ar biotite dating: an 40Ar-39 Ar laser-probe and TEM investigations of variably chloritised biotites. Contribiutions to Mineralogy and Petrology 145: 643-658.10.1007/s00410-003-0472-z.
 
4.
Domańska-Siuda J, 2006. Origin and evolution of mother melt ofthe hornblende-biotite granite of western part of the Strzegom massif (in Polish). PhD Thesis, Archiwum Uniwersytetu Warszawskiego: 176pp.
 
5.
Domańska-Siuda J, Bachliński R and Słaby E, 2004. Rb-Sr and Sm-Nd isotopic study of hornblende-biotite granite from the Strzegom-Sobótka massif and its enclaves. VIII Ogólnopolska Sesja Naukowa: Datowanie Minerałów i Skał: 11-14.
 
6.
Dodson MH and McClelland-Brawn E, 1985. Isotopic and paleomagnetic evidence for rates of cooling, uplift and erosion. Geological Society of America Memoirs 10: 315-325.10.1144/GSL.MEM.1985.010.01.26.
 
7.
Halas S, 2007. Low-blank crucible for Ar extraction from minerals at temperatures up to 1550° C. Geochronometria 27: 1-3, DOI 10.2478/v10003-007-0014-1.10.2478/v10003-007-0014-1.
 
8.
Kretz R, 1983. Symbols for rock-forming minerals. American Mineralogist 68: 277-279.
 
9.
Kural S and Morawski T, 1968. Strzegom-Sobótka granitic massif. Biuletyn Instytutu Geologicznego 227: 33-74.
 
10.
Maciejewski S and Morawski T, 1975. Zmienność petrograficzna granitów masywu strzegomskiego (Petrographic variability of granites from Strzegom Massif). Kwartalnik Geologiczny 19(1): 47-65 (in Polish).
 
11.
Majerowicz A, 1972. Masyw granitowy Strzegom-Sobótka. Studium petrologiczne (Strzegom-Sobótka granitic massif. Petrological study). Geologia Sudetica 6: 7-88 (in Polish).
 
12.
Mikulski SZ and Stein HJ, 2005. The Re-Os age for molybdenite from the Variscan Strzegom-Sobótka massif, SW Poland. In: Jingwen Mao and Frank P. Bierlein, eds, Mineral Deposit Research: Meeting the Global Challenge: 789-792. Springer.10.1007/3-540-27946-6_201.
 
13.
Mitchell JG and Taka AS, 1984. Potassium and argon loss patterns in weathered micas: implications for detrital mineral studies, with particular reference to the Triassic palaeogeography of the British Isles. Sedimentary Geology 39: 27-52.10.1016/0037-0738(84)90023-X.
 
14.
Pin C, Puziewicz J and Duthou JL, 1989. Ages and origins of a composite granitic massif in the Variscan belt: a Rb-Sr study of the Strzegom-Sobótka Massif, W Sudetes (Poland). Neues Jahrbuch für Mineralogie - Abhandlungen 160: 71-82.
 
15.
Puziewicz J, 1985. Petrologia skał masywu granitowego Strzegom-Sobótka (Petrology of rocks from Strzegom-Sobótka granitic massif. Conference Proceedings "Petrologia skał masywu granitowego Strzegom-Sobótka i jego osłony": 19-27 (in Polish).
 
16.
Puziewicz J, 1990. Masyw granitowy Strzegom-Sobótka. Aktualny stan badań (Strzegom-Sobótka granitic massif. Recent state of studies). Archiwum Mineralogiczne 45: 135-152 (in Polish).
 
17.
Puziewicz J, 1994. Zawartość tytanu w biotycie z granitoidów jako wskaźnik warunków krystalizacji magmy. Studium biotytu z metaaluminowych granitoidów masywu Strzegom-Sobótka (Titanium content in biotite from granitoids as indicator of magma crystalization conditions. Study of biotite in metaaluminic granitoids of Strzegom-Sobótka Massif). Archiwum Mineralogiczne 50(1): 89-134 (in Polish).
 
18.
Roberts HJ, Kelley SP and Dahl PS, 2001. Obtaining geologically meaningful 40Ar-39 Ar ages from altered biotite. Chemical Geology 172: 277-290.10.1016/S0009-2541(00)00255-2.
 
19.
Steiger RH and Jaeger E, 1977. Subcommision on geochronology: convention on the use of decay constants in geo- and cosmochronology. Earth and Planetary Science Letters 36: 359-362.10.1016/0012-821X(77)90060-7.
 
20.
Turniak K and Bröcker M, 2002. Age of the two-mica granite from the Strzegom-Sobótka massif: new data from U/Pb monazite and xenotime study. Mineralogical Society of Poland - Special Papers 20: 211-213.
 
21.
Turniak K, Tichomirowa M and Bombach K, 2005. Zircon Pbevaporation ages of granitoids from the Strzegom-Sobótka Massif (SW Poland). Mineralogical Society of Poland - Special Papers 25: 241-245.
 
22.
Wichrowska M, 1974. Biotyty z granitów strzegomskich (Biotites from Strzegom granites). Kwartalnik Geologiczny 18(1): 33-43 (in Polish).
 
23.
Wichrowska M, 1977. Pierwiastki śladowe w łyszczykach z granitoidów masywu Strzegom-Sobótka i Strzelin-Žulová (Trace elements in micas from granitoids of Strzegom-Sobótka and Strzelin-Žulová Massif). Biuletyn Instytutu Geologicznego 298: 209-261 (in Polish).
 
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ISSN:1733-8387
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