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Tytuł:
Provenance petrological study of the Upper Vendian and Cambrian clastic material; foreland of the Pomeranian Caledonides (northern Poland)
Autorzy:
Sikorska, M.
Powiązania:
https://bibliotekanauki.pl/articles/2059450.pdf
Data publikacji:
2000
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
northern Poland
Lower Cambrian
Upper Vendian
clastic material
zircon
Opis:
The provenance of clastic material in the oldest part of the sedimentary cover of the East European Craton, in northern Poland, is analysed. Analysis of the Żarnowiec Formation sandstones (Upper Vendian-lowest Cambrian) confirm earlier views of a local origin. The crystalline basement in the Kościerzyna IG 1 region mainly yielded enderbitic detritus while that in the Gdańsk IG 1 region provided migmatitic detritus. Triangle diagrams of the overlying, mature, sandy marine Cambrian show unequivocally that the detritus was transported from the craton interior. Analysis of mono- and polycrystalline quartz and cathodoluminescence (CL) analysis indicates erosion of metamorphic, magmatic and sedimentary rocks, and this is confirmed by CL observations of zircons. These results are consistent with the view that the Upper Vendian and Cambrian strata on the Pomeranian Caledonides foreland were formed on the passive margin of Baltica.
Źródło:
Geological Quarterly; 2000, 44, 3; 237-247
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Charakterystyka morfologiczna i geochemiczna kryształów cyrkonu z migmatytu ze Smreczyńskiego Wierchu (Tatry Zachodnie)
Morphological and geochemical characteristics of zircon crystals from Smreczyński Wierch migmatite (Western Tatra Mts.)
Autorzy:
Burda, J.
Powiązania:
https://bibliotekanauki.pl/articles/2074380.pdf
Data publikacji:
2005
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
kryształ cyrkonu
katodoluminescencja
migmatytyzacja
zircon morphology
cathodoluminescence
migmatites
Tatra Mts.
Opis:
In the Polish part of the metamorphic envelope of the granitoid Rohače pluton, migmatites are the predominant component. Migmatisation took place in the amphibolite facies conditions (T = 690–780C ; P =7.5–11 kbar). To observe the response of zircon crystals to the melt formation, zircon from the anatectic group of migmatites was investigated (both from leucosome and mesosome of stromatitic migmatite). Different generations of zircon present in leuco- and mesosome reflect different geological processes acting during the rock formation. Zircon from leucosome represent mainly the euhedral varieties, with two typological maxima: S1-2 (I generation) and S21-22 (II generation). Zircon from mesosome represents the anhedral varieties with one maximum at S1 (I gen-eration). In CL images the first generation (S1-2) comprises an inherited core surrounded by younger metamorphic and magmatic rims. The microchemical analyses showed that the inherited cores have higher Zr/Hf ratios than the overgrowing rims. The second genera-tion (S21-22) revealed only oscillatory zonation. The zones with strong luminescence are characterized by a decrease of Hf and U con-tent. Zircon showing polyphase internal structure might represent a component of mesosome which survived the dissolution in granitic melt, while zircon with oscillatory zonation might have crystallized from anatectic melt.
Źródło:
Przegląd Geologiczny; 2005, 53, 2; 127--133
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Gneiss protolith ages and tectonic boundaries in the NE part of the Bohemian Massif (Fore-Sudetic Block, SWPoland
Autorzy:
Oberc-Dziedzic, T.
Kryza, R.
Klimas, K.
Fanning, M.C.
Madej, S.
Powiązania:
https://bibliotekanauki.pl/articles/2059703.pdf
Data publikacji:
2005
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Bohemian Massif
East-West Sudetes boundary
zircon ages
Opis:
Published geochronological data, petrology, geochemistry and geological context of orthogneisses in the Strzelin and the Stachów complexes (NE-part of the Fore-Sudetic Block), together with structural observations help to locate the northern extension of the boundary between the East and West Sudetes within the poorly exposed NE margin of the Bohemian Massif. The Strzelin complex, in the east, comprises the Strzelin gneiss, with zircon ages of 600š7 and 568š7Ma, and the Nowolesie gneiss with a mean zircon age of 1020_ 1Ma. The Stachów complex to the west, which forms several tectonic klippen in the Strzelin Massif and in the Lipowe Hills Massif, contains the Gościęcice gneiss and pale Stachów gneiss, both yielding Late Cambrian zircon ages (~500š5 Ma). The orthogneisses in both complexes correspond to peraluminous S-type granites, but have different inherited zircon ages and display contrasting trace element characteristics, indicating different sources and petrogenetic histories. Based on the ages, petrology and overall geological context, the Strzelin orthogneiss is similar to the Keprník orthogneiss of the East Sudetes, whereas the orthogneisses of the Stachów complex correspond to rocks known from theWest Sudetes (e.g. the Izera and Śnieżnik orthogneisses). The Stachów and the Strzelin complexes are separated by the Strzelin Thrust, which may be interpreted as the northern extension of the boundary between the East and West Sudetes, i.e. part of the boundary between the Brunovistulian and Moldanubian terranes of the NE part of the Bohemian Massif.
Źródło:
Geological Quarterly; 2005, 49, 4; 363--378
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Rewizja wieku "najstarszych" skał w podłożu krystalicznym północno-wschodniej Polski
Revision of the "oldest" rocks age in the crystalline basement of NE Poland
Autorzy:
Krzemińska, E.
Wiszniewska, J.
Williams, I.S.
Powiązania:
https://bibliotekanauki.pl/articles/2074437.pdf
Data publikacji:
2006
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
pegmatyt
monacyt
ziarna cyrkonu
mikroskopia elektronowa
wysokopróżniowy mikroskop skaningowy
zircon
monazite
U-Pb SHRIMP geochronology
Late Paleoproterozoic
NE Poland
Opis:
The oldest geochronological results between 2.69–2.57 Ga was previously obtained by using K–Ar method on biotite from pegmatite from Jastrzębna IG–1 borehole. In consequence, in many published reports up to 1998, the Mazowsze (or Masovian) granitoid massif has been regarded as Archean age structure. Therewithal, other rocks in the area, e.g. Bargłów gneiss sequence traditionally were described as Archean in age. In the paper we present new U–Pb SHRIMP zircon and monazite results for above mentioned rocks which have been considered as Archean. Cathodoluminescence images and SHRIMP analysis were carried out for zircons and monazites from Jastrzebna IG–1 pegmatite of 514 m depth (a historical sample previously dated by K–Ar method) and for zircon magmatic cores from Bargłów IG–2 orthogneiss of the 708 m depth. The obtained U–Pb ages of 1826 š12 Ma (zircon) and 1789š34 Ma (monazite), and 1835š28 Ma (zircon) for two rock samples respectively have shown Paleoproterozoic origin. Only 4 of the 24 analysed zircons have clearly discordant results, which are all from the Jastrzebna pegmatite, where Pb–loss was possible (in partially metamict U–rich zircon grains). The new U–Pb SHRIMP dating indicates that Jastrzębna pegmatite and Bargłów magmatic protolith of the orthogneiss is only Late Paleoproterozoic in age and in general about 700 Ma younger than previously reported by K–Ar method. Therefore, there is no unequivocal evidence of the presence of Archean rocks in crystalline basement of NE Poland. This study has been undertaken as a part of a collaborative research agreement between the Polish Geological Institute and Geochronology and Isotope Geochemistry Research School of Earth Sciences of the Australian National University in Canberra.
Źródło:
Przegląd Geologiczny; 2006, 54, 11; 967-973
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wczesnokarboński wiek intruzji platformowych w podłożu krystalicznym NE Polski
Early Carboniferous age of the cratonic intrusions in the crystalline basement of NE Poland
Autorzy:
Krzemińska, E.
Wiszniewska, J.
Williams, I.S.
Powiązania:
https://bibliotekanauki.pl/articles/2074482.pdf
Data publikacji:
2006
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
zircon
U-Pb SHRIMP geochronology
closure temperature
mafic-alkaline magmatism
Early Carboniferous
NE Poland
Opis:
Three mafic-alkaline intrusive bodies in NE Poland: Ełk, Pisz and Tajno, have been dated recently with U-Pb SHRIMP method. An earlier Rb-Sr whole rock isochron of Ełk syenites pointed to an age 355š4 Ma, while K-Ar age estimates suggested a Late Paleozoic age of Pisz and Tajno rocks, however, in a wide range between 349-291 Ma and 327-289 Ma, respectively. In the paper, we present new geochronological results and discuss the problem of the closure temperatures for different minerals and different isotopic systems used in previous age determinations. Much of the early dating works has been done using K-Ar method. Biotite and K-feldspar retain radiogenic Ar quantitatively below 280 -200şC. Only if magmatic bodies cooled quickly and remained unmetamorphosed, K-Ar and Rb-Sr ages estimate accurately the intrusion emplacement. Zircon used for U-Pb datings has a closure temperature over 800şC, that is comparable to the temperature of magma’s solidus. Therefore U-Pb magmatic zircons dates could be interpreted as an intrusion emplacement ages. The obtained U-Pb results of 347.7 š8 Ma (Ełk) and 345.5š5 Ma (Pisz) have shown very consistent Early Carboniferous age of platform mafic-alkaline magmatic activity. This new U-Pb SHRIMP dating indicates that Ełk and Pisz intrusions are coeval and together with the Tajno alkaline-carbonatite massif could be affined with the Late Devonian Kola Alkaline Carbonatite Province (KACP).
Źródło:
Przegląd Geologiczny; 2006, 54, 12; 1093-1098
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Late Svecofennian sedimentary basins in the crystalline basement of NE Poland and adjacent area of Lithuania: ages, major sources of detritus, and correlations
Autorzy:
Krzeminska, E.
Wiszniewska, J.
Skridlaite, G.
Williams, I. S.
Powiązania:
https://bibliotekanauki.pl/articles/2059225.pdf
Data publikacji:
2009
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Fennoscandia
Sarmatia
Greenland
Svecofennian basin
detrital zircon
geochronology
Opis:
The Pre cam brian base ment of Lith u a nia and NE Po land, much of which is metasedimentary paragneiss, can be ac cessed only by cores from deep bore holes. Ion microprobe dat ing of de tri tal zir cons from sam ples of these meta sedi ments and the geo chem i cal sig na tures of the rocks pro vide new in sights into their age and prov e nance. De tri tal zir cons from meta sedi ments from Jastrzebna and Monki have Pb iso to pic ages in the ranges 3.14–1.83 and 3.53–1.82 Ga, re spec tively. Sim i lar re sults have been ob tained from the Lith u a nian Lazdijai and Bliudziai paragneisses. About 30% of the ana lysed Pol ish de tri tal zir con cores are of Late Archaean age (2.90–2.60 Ga) and about 70% are Palaeoproterozoic (2.10–1.90 Ga), sim i lar to the age dis tri bu tions of de tri tal zir con from Svecofennian meta sedi ments ex posed in Cen tral Swe den and South ern Fin land. The youn gest de tri tal zir con sub-groups in di cate max i mum de po si tion ages of about 1.86 Ga, sim i lar to the ages of ex posed Svecofennian sed i men tary bas ins. Pos si ble source rocks of com pa ra ble ages and af fin i ties can be found within Fennoscandia, Green land and Sarmatia.
Źródło:
Geological Quarterly; 2009, 53, 3; 255-272
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Early Carboniferous (~337 Ma) granite intrusion in Devonian (~400 Ma) ophiolite of the Central-European Variscides
Autorzy:
Kryza, R.
Powiązania:
https://bibliotekanauki.pl/articles/2059145.pdf
Data publikacji:
2011
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Variscides
ophiolites
SHRIMP zircon geochronology
Opis:
The Central-Sudetic ophiolites comprise mafic-ultramafic complexes around the E and S edges of the Góry Sowie Massif in SW Poland and are recognized as fragments of Devonian (~400 Ma old) oceanic crust. They contain small rodingite bodies and tectonized granite dykes that potentially can highlight the igneous, metamorphic and structural development of the ophiolitic suites. The granite dykes have been tentatively correlated with the Variscan granitoids of the Strzegom-Sobótka Massif to the north. However, new U-Pb SHRIMP zircon data for granites from the serpentinite quarry at Jordanów show a concordia age of 337 š4 Ma for the main zircon population, and of 386 š10 Ma for minor inheritance. Thus, the age of the granite is considerably older than the ages of the Strzegom-Sobótka granitoids, dated at ~310-294 Ma. The granite dyke has a similar age as some other granitoids found near the ophiolitic fragments, e.g., the Niemcza granitoids to the south, dated at 338 +2/-3 Ma; these older granitoids all represents a relatively early stage of granitoid magmatism recorded in that part of the Variscan Orogen. The age of the granitoid dyke within serpentinites confirms that the Paleozoic ophiolites were incorporated into the continental crust already in early Visean times.
Źródło:
Geological Quarterly; 2011, 55, 3; 213-222
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
SHRIMP U-Pb zircon chronology of the Polish Western Outer Carpathians source areas
Autorzy:
Budzyń, B.
Dunkley, D. J.
Kusiak, M. A.
Poprawa, P.
Malata, T.
Skiba, M.
Paszkowski, M.
Powiązania:
https://bibliotekanauki.pl/articles/191475.pdf
Data publikacji:
2011
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
zircon
U-Pb geochronology
ion microprobe
provenance
Carpathians
Opis:
The Western Outer Carpathians flysch of Poland comprises clasts of crystalline rocks representing source areas that supplied sedimentary basins with clastic material. Zircon from quartz syenite and granite cobbles representing the Silesian Ridge, the currently unexposed source area located at the southern margin of the Silesian Basin, yielded uniform U-Pb dates of 604š6 Ma and 599š6 Ma. These are interpreted as the age of igneous crystallization. Similarly, zircon from a gneiss cobble derived from the northern source terrain gave 610š6 Ma date, which is interpreted as the age of crystallization of the granitic protolith to the gneiss. The Neoproterozoic magmatism is interpreted to have occurred at the Gondwana active margin.
Źródło:
Annales Societatis Geologorum Poloniae; 2011, 81, No 2; 161-171
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Ambiguous geological position of Carboniferous rhyodacites in the Intra-Sudetic Basin (SW Poland) clarified by SHRIMP zircon ages
Autorzy:
Kryza, R.
Awdankiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/2058977.pdf
Data publikacji:
2012
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Sudetes
Variscan orogeny
Carboniferous
SHRIMP zircon dating
volcanism
subvolcanic intrusions
Opis:
Rhyodacite sheets (the Sady Górne Rhyodacites) in the lowermost part of the Permo-Carboniferous Intra-Sudetic Basin molasse fill have been mapped as intrusives but, later on, based on ambiguous field and petrographic evidence, reinterpreted as lower Carboniferous lavas and tuffs; if so, they would mark the earliest episode of late-orogenic volcanism in the Intra-Sudetic Basin and in the whole Sudetes region in SW Poland. However, re-examination of field relationships and new observations are consistent with an intrusive emplacement of the rhyodacites as conformable to semiconformable, simple to composite sheets. SHRIMP zircon study indicates that the rhyodacites contain rare inherited zircons of ca. 560 Ma, and ca. 470 Ma (or slightly older), and a main population of zircons with an average concordia age of 306.1 š2.8 Ma. This latter age documents the emplacement of the rhyodacites during a mid/late late Carboniferous (Westphalian) stage of volcanism in the Intra-Sudetic Basin in the Central European Variscides. This post-orogenic volcanism was possibly initiated several million years later than previously assumed, and could have comprised a few pulses over a relatively prolonged time span of millions of years.
Źródło:
Geological Quarterly; 2012, 56, 1; 55-66
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Late stage Variscan magmatism in the Strzelin Massif (SW Poland): SHRIMP zircon ages of tonalite and Bt-Ms granite of the Gęsiniec intrusion
Autorzy:
Oberc-Dziedzic, T.
Kryza, R.
Powiązania:
https://bibliotekanauki.pl/articles/2058999.pdf
Data publikacji:
2012
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Strzelin Massif
Gęsiniec composite intrusion
Variscan granitoids
SHRIMP zircon ages
Opis:
The Gęsiniec composite intrusion in the northern part of the Strzelin Massif (Fore-Sudetic Block, SW Poland) was formed in the course of three late Variscan magmatic episodes: tonalitic I, granodioritic, and tonalitic II/granitic. The age of the Gęsiniec tonalite, 295 š3 Ma, is the same as that of another tonalite body in the southern part of the Strzelin Massif, the Kalinka tonalite. The younger biotite-muscovite (Bt-Ms) granite, in a dyke cutting the Gęsiniec tonalite, has an indistinguishable isotopic age of 295 š5 Ma; it contains, however, inherited zircons with ages between ca. 1.5 Ga to 374 Ma, similar to zircon ages from surrounding gneisses. This suggests that the magmatic protolith of gneisses and the magma of the Bt-Ms granite could have come from similar sources, or that the magma of the Bt-Ms granite was contaminated by the gneisses. Both the tonalite and Bt-Ma granite represent a late stage of the granitoid magmatism in the eastern part of the Variscan orogen.
Źródło:
Geological Quarterly; 2012, 56, 2; 225-236
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Neoproterozoic pegmatite from Skoddefjellet, Wedel Jarlsberg Land, Spitsbergen: Additional evidence for c. 640 Ma tectonothermal event in the Caledonides of Svalbard
Autorzy:
Majka, Jarosław
Larionov, Alexander N.
Gee, David G.
Czerny, Jerzy
Pršek, Jaroslav
Powiązania:
https://bibliotekanauki.pl/articles/2051474.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Arctic
Svalbard
zircon
monazite
uraninite
geochronology
Źródło:
Polish Polar Research; 2012, 1; 1-17
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Baddeleyite segregations in zircon of the Azov zirconium-rare-earth deposit (Ukrainian Shield)
Autorzy:
Voznyak, Dmytro K.
Chernysh, Dariia D.
Melnikov, Volodymyr S.
Ostapenko, Stepanyda S.
Powiązania:
https://bibliotekanauki.pl/articles/127603.pdf
Data publikacji:
2013
Wydawca:
Polskie Towarzystwo Mineralogiczne
Tematy:
baddeleyite
zircon
high-thermobaric CO2-fluid flows
Azov zirconium-rare-earth deposit
Opis:
Baddeleyite as inclusions in zircon crystals is described for the first time from the ore zone of the Azov zirconium-rare-earth deposit in the Volodarsky (Pivdennokalchytsky) syenite Massif in the Ukrainian Shield. The main admixture in the zircon containing baddeleyite is hafnium (0.68 wt%). The baddeleyite occurs in a substance that fills cracks and that probably corresponds to glass. The chemical compositions of four baddeleyite segregations, and of the hosting glass, are presented. The baddeleyite formed as a result of interaction between zircon and silicate melt with a low SiO2 content. The silicate melt formed under the influence of highthermobaric CO2-fluid flows on the rock.
Źródło:
Mineralogia; 2013, 44, 3/4; 125-131
1899-8291
1899-8526
Pojawia się w:
Mineralogia
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Heavy-mineral, mineral-chemical and zircon-age constraints on the provenance of Triassic sandstones from the Devon coast, southern Britain
Autorzy:
Morton, Andrew
Hounslow, Mark W.
Frei, Dirk
Powiązania:
https://bibliotekanauki.pl/articles/94463.pdf
Data publikacji:
2013
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
heavy minerals
zircon
provenance
Triassic
Devon
ciężkie minerały
cyrkon
proweniencja
Trias
Dewon
Opis:
An integrated heavy-mineral, mineral-chemical and zircon-dating study of the Triassic succession exposed on the south Devon coast, in the western part of the Wessex Basin, indicates derivation from a combination of granitic and metasedimentary lithologies of ages of mostly over 550 Ma. These sources were probably located at a relatively proximal location near the southern margin of the basin. Derivation from more distal sources in the Armorican Massif or local Variscan sources to the west appears unlikely in view of the scarcity of Permo-Carboniferous (Variscan-age) zircons. The Budleigh Salterton Pebble Bed Formation was derived from a different combination of source lithologies than the Otter Sandstone Formation, the former including staurolite-grade metasediments that were absent in the catchment area of the Otter Sandstone. The Devon coast succession has provenance characteristics that differ from equivalent sandstones further east in the Wessex Basin, and from sandstones in the East Irish Sea Basin to the north. These differences indicate that sediment supply patterns to the linked Triassic basin systems in southern Britain are complex, involving multiple distinct sub-catchment areas, and that heavy-mineral studies have considerable potential for unravelling these sub-catchment area sources.
Źródło:
Geologos; 2013, 19, No. 1-2; 67-85
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Niemcza diorites and moznodiorites (Sudetes, SW Poland) : a record of changing geotectonic setting at ca. 340 Ma
Autorzy:
Pietranik, A.
Storey, C.
Kierczak, J.
Powiązania:
https://bibliotekanauki.pl/articles/2059736.pdf
Data publikacji:
2013
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Variscidies
Niemcza Zone
diorites
LA-ICP-MS zircon age
potassic magmatism
Opis:
Granites sensu lato in the Sudetes intruded in several episodes during the Variscan orogeny recording different stages of crust and mantle evolution. Correlating precise ages with geochemistry of the Variscan granites provides information on the evolution of these sources within the Variscan orogen. The Variscan intrusive rocks from the Niemcza Zone (Bohemian Massif, Sudetes, SW Poland) include undeformed dioritic to syenitic rocks and magmatically foliated granodiorites. In this study we analysed low SiO2 (48–53 wt.%) monzodioritic rocks from Przedborowa and Koźmice. The monzodiorites contain late-magmatic zircons with ages of 341.8 ± 1.9 Ma for Przedborowa and 335.6 ± 2.3 Ma for Koźmice, interpreted as emplacement ages of the dioritic magmas. Older Przedborowa rocks are lower in K, Mg, Rb and Ni than the Koźmice rocks and similar compositional trend is also observed in the Central Bohemian Plutonic Complex. The implication is that the mantle underlying the Niemcza Zone became more enriched from ca. 342 to ca. 336 Ma, probably following the collision of the Saxothuringian and Moldanubian/Lugian domains. The magmatism related to the collision occurred ca. 12 Ma later than that in the Central Bohemian Plutonic Complex, but was accompanied by a similar change in magma chemistry from high-K (Przedborowa) to shoshonitic (Koźmice, Kośmin enclaves) and probably to ultrapotassic (Wilków Wielki).
Źródło:
Geological Quarterly; 2013, 57, 2; 325--334
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Variscan granitoid plutonism in the Strzelin Massif (SW Poland) : petrology and age of the composite Strzelin granite intrusion
Autorzy:
Oberc-Dziedzic, T.
Kryza, R.
Pin, C.
Madej, S.
Powiązania:
https://bibliotekanauki.pl/articles/2059728.pdf
Data publikacji:
2013
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
zircon SHRIMP geochronology
composite granitoid plutons
Variscan granitoids
Strzelin Massif
Opis:
Petrological data and recently published U/Pb zircon SHRIMP ages reveal a protracted Variscan magmatic evolution in the Strzelin Massif (SW Poland), with three main stages of granitoid plutonism: 1 – tonalitic I, 2 – granodioritic and 3 – tonalitic II/granitic. The granitoids of the second and third stages form the Strzelin intrusion that is composed of three varieties: medium-grained biotite granite, fine-grained biotite granite and fine-grained biotite-muscovite granite. New SHRIMP data show that the medium-grained and fine-grained biotite granites comprise different zircon populations that reflect complex and prolonged plutonic processes. Two distinct magmatic events seem to be represented by well-defined zircon populations with apparent 206Pb/238U ages of 303 ± 2 Ma in the medium-grained biotite granite, and 283 ± 8 Ma in the fine-grained biotite granite. These dates, however, do not necessarily reflect the true magmatic ages, possibly being “rejuvenated” by radiogenic lead loss in zircons (impossible to resolve based on routine SHRIMP data). Based on field evidence, the third variety, the biotite-muscovite granite, postdates both types of biotite granites. The petrographic and geochemical features, including Nd isotope signature, along with various zircon inheritance patterns and ages, suggest that the parental magmas of the three granites originated from different crustal sources and were emplaced during three successive magmatic pulses.
Źródło:
Geological Quarterly; 2013, 57, 2; 269--288
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 37

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