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Wyświetlanie 1-9 z 9
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
  • odwiedzone
Tytuł:
An insight into a gneiss core of the Orlica–Śnieżnik Dome, NE Bohemian Massif : new structural and U-Pb zircon data
Autorzy:
Redlińska-Marczyńska, A.
Żelaźniewicz, A.
Fanning, C. M.
Powiązania:
https://bibliotekanauki.pl/articles/2059909.pdf
Data publikacji:
2016
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Cambrian
migmatites
Variscan orogeny
SHRIMP
Sudetes
Opis:
The Orlica–Śnieżnik Dome in the Sudetes, the NE Bohemian Massif, embraces two formations of felsic gneisses of controversial origin and evolution. Our study shows that despite similar geochemical signatures, they carry systematic minor differences in mineral, isotope, zircon and geothermobarometric characteristics. Four variants of the Gierałtów gneisses include migmatites and have a longer structural history than the Śnieżnik augen orthogneisses. U-Pb SHRIMP analyses yielded U-Pb ages of ~500 Ma for cores and ~498 Ma for wide outer parts of zircon grains in the twice-folded Gierałtów gneisses, and an age of ~500 Ma for a discordant neosome vein. Neoproterozoic metasediments were among precursors of the lithologically diversified Gierałtów Gneiss Formation. First deformation, metamorphism, and migmatisation of these rocks occurred at 515–475 Ma and overlapped with the development and emplacement of a porphyritic S-type granite precursor to the Śnieżnik Gneiss Formation. The metagranite (= Śnieżnik augen orthogneiss) embraced migmatitic xenoliths. Zircon grains from such xenoliths revealed distorted and replaced cores which yielded U-Pb ages that dispersed around 507–487 Ma, whilst wide darker poorly zoned outgrowths yielded ages from ~343 Ma to ~325 Ma (mean ~340 Ma). These outgrowths were interpreted as a record of Carboniferous metamorphism assisted by rich Zr- and U-carrying fluids. The Variscan metamorphic overprint was heterogeneous, and variously affected rocks of the two gneiss formations.
Źródło:
Geological Quarterly; 2016, 60, 3; 714--736
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Zircon U-Pb ages of granitoid apophyses in the western part of the Kłodzko–Złoty Stok Granite Pluton (SW Poland)
Autorzy:
Mikulski, S.Z.
Williams, I. S.
Powiązania:
https://bibliotekanauki.pl/articles/2059727.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Variscan granitoids
apophyses
zircon
SHRIMP geochronology
Sudetes
Opis:
Granitoids from the Graniec–Bardo and Myszak apophyses of the Kłodzko–Złoty Stok (KZS) Granite Pluton that intrude the Upper Paleozoic flysch of the Bardo Unit have zircon U-Pb ages, measured by SHRIMP, of 341.6 ± 2.8 Ma and 341.4 ± 2.2 Ma, respectively. These results augment our previous dating that recorded a short period of Middle Mississippian (Visean) hypabyssal magmatism that produced a variety of KZS igneous rocks of different compositions between ca. 341 and 331 Ma. The Graniec–Bardo and Myszak apophyses belong to the earliest stage of the pluton emplacement. Geochemical and petrographic studies of the dated samples indicate that they are biotite- and hornblende-rich tonalite and syenogabbro of diverse composition and typical of rocks originating from hybrid magmas formed in the geotectonic transition from an early stage collisional granitoid emplacement to its fast orogenic uplift. The polymetallic auriferous ore mineralisation of contact metasomatic type found in intimate contact with the Graniec–Bardo apophysis near Bardo Śląskie may also be of Visean age.
Źródło:
Geological Quarterly; 2014, 58, 2; 251--262
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The Saxothuringian Terrane affinity of the metamorphic Stachów Complex (Strzelin Massif, Fore-Sudetic Block, Poland) inferred from zircon ages
Autorzy:
Oberc-Dziedzic, T.
Kryza, R.
Madej, S.
Pin, C.
Powiązania:
https://bibliotekanauki.pl/articles/2059781.pdf
Data publikacji:
2018
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Stachów Complex
Saxothuringian Terrane
SHRIMP zircon ages
Strzelin Massif
Opis:
The Saxothuringian Terrane defined in the western part of the Bohemian Massif is regarded to have easterly continuations in the Karkonosze–Izera Massif, the Kamieniec Ząbkowicki Belt and the Orlica–Śnieżnik Dome. All these units comprise Early Ordovician (~500 Ma) metagranites associated with mica schists. Even more to the east, ~500 Ma metagranites and metasedimentary rocks occur also in the Strzelin Massif of the East Sudetes, where they are known as the pale and dark Stachów gneisses, respectively. Altogether, these rocks form the Stachów Complex which was thrust on the Strzelin Complex of the Brunovistulicum Terrane during the Variscan Orogeny. The contribution presents lines of evidence for a Saxothuringian affinity of the Stachów Complex rocks: (1) the new SHRIMP U-Pb age data of zircons from both the pale and dark Stachów gneisses; (2) the indication that the zircon age spectra from the ~500 Ma granitoids and their accompanying metasedimentary rocks are similar to those found in other parts of the Sudetes; (3) the “Armorican” age pattern of inherited zircons of the pale Stachów gneisses, as also observed in the Saxothuringian Terrane; (4) the similarity of trace elements and Sm-Nd isotope data of the Stachów gneisses and correlative rocks from the Karkonosze–Izera Massif and the Orlica–Śnieżnik Dome.
Źródło:
Geological Quarterly; 2018, 62, 2; 237--256
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:
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:
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
Tytuł:
Last stage of Variscan granitoid magmatism in the Strzelin Massif (SW Poland) : petrology and age of the biotite-muscovite granites
Autorzy:
Oberc-Dziedzic, T.
Kryza, R.
Pin, C.
Powiązania:
https://bibliotekanauki.pl/articles/2060004.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
biotite-muscovite granite
cordierite nodules
SHRIMP zircon ages
Variscan granitoids
Strzelin Massif
Opis:
New petrographic and geochemical data show some differences between Variscan Bt-Ms granites occurring either as small plutons or dykes in the Strzelin Massif (SW Poland). The granites of the Gromnik and Górka Sobocka plutons are rich in micas and crystallized from "wet" magmas; the granites in the dykes and in the Gębczyce pluton are mica-poorer and cordierite-bearing rocks, derived from “dryer” magmas. The lower initial eNd values in the Bt-Ms granites of the dykes, compared with those in the plutons, reflect a more "crustal" signature of the former, possibly due to local crustal assimilation, via AFC, shortly before emplacement. Much more radiogenic initial 87Sr/86Sr ratios in the dykes, up to 0.726, further suggest the involvement of extraneous, hydrous crustal fluids enriched in 87Sr during the evolution of late-stage magma derivatives. The new U-Pb SHRIMP zircon age of 296 ± 6 Ma for the Gębczyce Bt-Ms granite shows that this body belongs to the third stage of magmatism in the Strzelin Massif. The U-Pb SHRIMP zircon data for the Bt-Ms granite dykes provide ages similar to those of their host rocks: c. 295 Ma for the Gęsiniec tonalite and the enclosed Bt-Ms granite, and c. 285 Ma for the Strzelin biotite granite and its Bt-Ms granite dykes. These new data from peraluminous rock-types complement our previous studies focused on the tonalites, granodiorites and biotite granites, and shed light on the late-stage igneous evolution of the Strzelin Massif.
Źródło:
Geological Quarterly; 2015, 59, 4; 718--737
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A Carboniferous/Permian, calc-alkaline, I-type granodiorite from the Małopolska Block, Southern Poland: implications from geo chemi cal and U-Pb zircon age data
Autorzy:
Żelaźniewicz, A.
Pańczyk, M.
Nawrocki, J.
Fanning, M.
Powiązania:
https://bibliotekanauki.pl/articles/2059094.pdf
Data publikacji:
2008
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Brunovistulian
Upper Silesian Block
Kraków-Lubliniec fault zone
SHRIMP
Variscan foreland
strike-slip
Opis:
A granodiorite from bore hole WB-102A in the Dol ina Będkowska, the Małopolska Block (MB), South ern Po land, yielded a mean U-Pb zir con age of 300 š3 Ma with SHRIMP II. No in her ited older com po nent was de tected. Geo chemically, it is a K-rich, I-type, calc-al ka line granodiorite with su pra-subduction char ac ter is tics (neg a tive Nb and Ti anom a lies). Silicic ig ne ous rocks are abun dant at the MB mar gin along the Kraków-Lubliniec Fault Zone (KLFZ) across which it ad joins to the Up per Silesian Block (USB) where such rocks are scarce. Both blocks be long to the Variscan fore land. Gra nitic rocks can not, how ever, gen er ate at fore land set tings. Thus, the hy poth e sis is put for ward that the par ent melt for the silicic rocks was de rived from the thick ened lower crust of the Variscan orogenic belt ow ing to extensional de com pres sion melt ing, and trans ported away to wards pul-apart open ings de vel oped along the crustal-scale fault zone (KLFZ) that un der went a com plex strike-slip his tory around the Car bon if er ous/Perm ian bound ary.
Źródło:
Geological Quarterly; 2008, 52, 4; 301-301
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-9 z 9

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