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Tytuł:
U-Pb and K-Ar geochronology of the subvolcanic rock pebbles from the Cretaceous and Paleogene gravelstones and conglomerates of the Pieniny Klippen Belt (Carpathians; Poland, Slovakia) – relevance for tectonic evolution and palaeogeography
Autorzy:
Poprawa, Paweł
Krobicki, Michał
Nejbert, Krzysztof
Krzemińska, Ewa
Armstrong, Richard
Pecskay, Zoltan
Powiązania:
https://bibliotekanauki.pl/articles/24202117.pdf
Data publikacji:
2023
Wydawca:
Akademia Górniczo-Hutnicza im. Stanisława Staszica w Krakowie. Wydawnictwo AGH
Tematy:
Pieniny Klippen Belt
geochronology
palaeogeography
Opis:
In the Pieniny Klippen Belt (PKB), the Cretaceous and Paleogene conglomerates and cohesive debrites commonly contain pebbles and blocks of the subvolcanic rocks among other, mainly sedimentary rocks (e.g. multicoloured sandstones, oolitic limestones, dark bivalve coquinas, dolostones, etc.). This detritus was interpreted as derived from the Andrusov Ridge located south of the PKB basin (Birkenmajer, 1988). Age of these subvolcanic rocks, regarded to represent subduction-related igneous activity, was previously constrained by K-Ar whole rock dating as c. 140–90 Ma, leading to suggestion that during Late Jurassic to Early Cretaceous PKB basin developed on oceanic lithosphere, subducted during at the end of Early Cretaceous (Birkenmajer, 1988). Within this study, the geochemical composition, the K-Ar whole rock age and the U-Pb zircon ages of the above mentioned subvolcanic rocks were studied. The pebbles are well rounded. They are represented by granitic and subvolcanic andesitic-type rocks (mainly andesite, basaltic andesite, basaltic trachyandesite, trachyandesite and rhyolitic pebbles, and rare dacite, tephrite, trachybasaltic and basaltic pebbles). Domination of andesitic pebbles, bimodal spectrum of volcanic rocks with high content of SiO2 (rhyolites, dacites) and Na2O and K2O within mafic and transitional ones is observed. Their petrographic character and geochemical analysis of concentration of rare elements with MgO > 2% ratio and La/Yb 4–35, Sc/Ni < 1.5, Sr/Y < 20, Ta/Yb > 0.1, Th/Yb > 1 values, indicate magmatic island arc of active continental margin similar to Andean-type subduction regime. The K-Ar whole rock dating was performed for 17 samples. The obtained ages cover mainly the Early Cretaceous time span, with the most data representing the Barremian-Albian, therefore are coherent with Birkenmajer (1988) results. However, the U-Pb SHRIMP zircon dating reveled different results. Most of the analyzed subvolcanic rock samples (9) give ages in the narrow range of c. 270–266 Ma. The ages are based on concordant data with amount of measured point in a range of 20–30, and are characterized by low error bars, usually lower than ±2 Ma. In addition, one sample of subvolcanic rock gave lower quality results, with a few youngest, partly concordant, zircons grains giving the age of 251.0 Ma ±8.5 Ma. Moreover, one sample of orthogenesis was analyzed, which is regarded to represent crust on which the volcanic arc developed. In this case the U-Pb SHRIMP zircon dating result is 493.9 Ma ±4.1 Ma. We regard these pebbles/blocks to be derived from the Inner Carpathians, assuming therefore lack of the Andrusov Ridge located south of the PKB basin (comp. Plašienka, 2018). The results of K-Ar whole rock dating is representative for intensive diagenetic overprint, rather than age of the rock. The U-Pb data clearly indicate, that subduction-related magmatic arc developed during the middle Permian (Guadalupian). This follows, that the oceanic crust was of the middle Permian or older age, and thus cannot be related to the Jurassic-Early Cretaceous development of the PKB basin. The magmatic arc was presumably connected with southern margin of Laurusia and subduction of oceanic crust of the Paleotethys (proto-Vardar Ocean?).
Źródło:
Geotourism / Geoturystyka; 2023, 1-2 (72-73); 58--58
1731-0830
Pojawia się w:
Geotourism / Geoturystyka
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:
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:
K/Ar geochronology of igneous amphibole phenocrysts in Miocene to Pliocene volcaniclastics, Styrian Basin, Austria
Autorzy:
Bojar, H. P.
Bojar, A. V.
Hałas, S.
Wójtowicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/2060550.pdf
Data publikacji:
2013
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
geochronology
igneous amphibole
volcanic tuffs
Styrian Basin
Opis:
We present fifteen new K/Ar ages on amphibole phenocrysts of Neogene volcaniclastic rocks from the Styrian Basin, Austria. The westernmost sub-basin of the Pannonian Basin is the Styrian Basin, which hosts a large number of phreatomagmatic tuff occurrences beside Middle Miocene shield volcanoes and Pliocene effusive alkaline volcanic rocks. The investigated tuffs contain the well-known mantle xenoliths and frequent amphibole and pyroxene phenocrysts. The new K/Ar ages indicate that the Late Miocene phreatomagmatic volcanism started in Pontian (7.51 Ma) and ended in Romanian (2.73 Ma) times. The complete interval of the youngest volcanism in the Styrian Basin covers 5.8 Ma, similar to the volcanism of the western part of the Pannonian Basin and the Nógrád/Novohrad area (West Carpathians). The dated volcanic occurrences display NNW–SSE oriented arrays which are approximately parallel to the Auersbach basinal high zone. The new data indicate that the Late Miocene to Pliocene volcanism of the Styrian Basin is synchronous with the onset of a regional compressional event and eastward tilting of the Styrian basin fill.
Źródło:
Geological Quarterly; 2013, 57, 3; 405--416
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:
Geochemistry and geochronology of the Jawornik granitoids, Orlica–Śnieżnik Dome, Sudetes, Poland
Autorzy:
Białek, Dawid
Powiązania:
https://bibliotekanauki.pl/articles/2060123.pdf
Data publikacji:
2020
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Jawornik granitoids
geochemistry
geochronology
Sudetes
Variscan
granitoids
Opis:
The Jawornik granitoids intrude, in vein-like form, a sequence of a polymetamorphic metavolcanic and metapelitic rocks of the Orlica-Śnieżnik Dome, Sudetes, Poland. This paper provides whole-rock geochemical data, sensitive high-resolution ion microprobe (SHRIMP) U-Pb zircon geochronological data as well as 40Ar-39Ar age determinations to constrain the genetic and temporal relationships of the different rock types forming these veins. Based on macroscopically visible features of the granitoids and their relationship with tectonic structures visible in the country rocks, four varieties of the Jawornik granitoids have been distinguished: amphibole- and biotite-bearing granites (HBG), biotite-bearing granites (BG), biotite- and muscovite-bearing granites (BMG) and muscovite-bearlng granites (MG). The Jawornik granitoids as a whole show a limited but significant variation in major element chemical composition, with SiO2 ranging from 65 to 76 wt.% (average 69.16 wt.%, n = 24). They are subalkalic, peraluminous and calc-alkaline [average A/CNK = 1.07, average (Na2O + K2O) = 7.75, average (Fe2O3t/(Fe2O3t + MgO) = 0.59]. Close inspection of their geochemical parameters showed that the samples investigated can be subdivided into two groups. The first group, the HBG, BG, and BMG varieties, comprising most of the granitoids in the Złoty Stok-Skrzynka Tectonic Zone, were formed by melting of greywackes or/and amphibolites. The MG, belonging to the second group, were formed by partial melting of a more felsic source. The HBG yielded a zircon U-Pb age of 351 ±1.3 Ma and well-defined Ar-399Ar plateau ages for hornblende (351.1 ±3.9 Ma) and coexisting biotite (349.6 ±3.8 Ma), indicating probably the oldest magmatic event in this region. Zircons from the MG, the youngest rock variety on the basis of their relationship with the tectonic structures in the host rocks yielded a U-Pb age of 336.3 ±2.4 Ma, though based on three points only. The biotites and muscovites from the BMG have Ar-39Ar plateau ages of 344.1 ±4.7 Ma and 344.6 ±3.8 Ma, respectively. These data, in combination with already published isotopic ages, suggest that the Jawornik granitoids intruded host rocks of the Orlica-Śnieżnik Dome in three stages, at ~350, ~344 and ~335 Ma.
Źródło:
Geological Quarterly; 2020, 64, 4; 942--957
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
New 40Ar-39Ar age constrains for magmatic and hydrothermal activity in the Holy Cross Mts. (southern Poland)
Autorzy:
Nawrocki, J.
Salwa, S.
Pańczyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/2060553.pdf
Data publikacji:
2013
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Ar-Ar geochronology
diabases
mineralization
Holy Cross Mountains
Opis:
New 40Ar-39Ar isotope ages of diabase intrusions from the Holy Cross Mountains (Poland) confirm the presence of at least two events of Paleozoic magmatic activity in the study area. The oldest, latest Silurian/earliest Devonian (ca. 424–416 Ma) episode is recorded by a diabase from the Bardo Syncline (Zarobiny PIG-1 borehole) in the Kielce Region. A younger, Serpukhovian (ca. 331–323 Ma) event is documented by a diabase from the Milejowice-1 borehole drilled in the Łysogóry Region. The diabase intrusion penetrated by the Wzorki-1 borehole, also located in the Łysogóry Region, is most probably of the same age. It provided, however, consistent mid-Triassic (243 Ma) 40Ar-39Ar isotopic age reflecting its pervasive hydrothermal alteration. The first stage of the post-Caledonian hydrothermal activity in the Holy Cross Mts. which produced polymetallic copper and iron-bearing mineralisation may be linked with the younger magmatic phase defined here. The second stage of post-Caledonian hydrothermal activity in the Holy Cross Mts., associated with the lead-zinc mineralisation, may be correlated with the Middle Triassic hydrothermal event recorded in the Wzorki diabase. Suggestions of temporal relationships between magmatic/hydrothermal activities and mineralisation events should, however, be constrained by further detailed geochemical and mineralogical studies.
Źródło:
Geological Quarterly; 2013, 57, 3; 551--560
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:
Zircon U-Pb dating of igneous rocks in the Radzimowice and Wielisław Złotoryjski auriferous polymetallic deposits, Sudetes, SW Poland
Autorzy:
Mikulski, S. Z.
Williams, I. S.
Powiązania:
https://bibliotekanauki.pl/articles/191720.pdf
Data publikacji:
2014
Wydawca:
Polskie Towarzystwo Geologiczne
Tematy:
zircon
SHRIMP geochronology
gold deposit
porphyries
Variscides
Sudetes
Opis:
A rhyolite porphyry in the Radzimowice deposit at Bukowinka Hill has a SHRIMP zircon U-Pb age of 314.9 ± 3.1 Ma. This is consistent with previous zircon dating of a monzogranite and a rhyodacite (ca. 315 Ma) in the Żeleźniak sub-volcanic intrusion (ZI), considered to be the igneous rocks, representing the oldest magmatic pulses in the region. First-stage mesothermal auriferous sulphide mineralization in the deposit was connected to hydrothermal processes, associated with the rhyodacite intrusions. This was followed by tectonic activity and younger alkaline magmatism in a post-collisional geotectonic setting. The first-stage Au-bearing sulphide mineralization was cataclased and overprinted by younger epithermal base-metal sulphides with microscopic Au, associated with Bi-Te-Ag minerals. The younger magmatic pulses are represented by porphyritic andesites and lamprophyric dykes, which cut the ZI. Zircon from these dykes yielded ages of 312.8 ± 2.8 Ma for an andesite porphyry and 312.4 ± 4 Ma for a lamprophyre. All these magmatic pulses, evidenced in the Radzimowice deposit, are considered to be the oldest post-orogenic sub-volcanic magmatism cutting the basement of the intramontane basins in the Sudetes, on the NE margin of the Bohemian Massif. A rhyolite porphyry in the famous 'Organy' exposure at Wielisław Złotoryjski (WZ) on the SE margin of the North-Sudetic Basin is younger, 297.5 ± 2.8 Ma. Vein-type auriferous ore mineralization, hosted by Early Palaeozoic graphitic schists in intimate contact with rhyolite porphyry in WZ, is also correlated with this magmatism. The auriferous ore mineralization at Radzimowice and Wielisław Złotoryjski formed at different times, during different magmatic pulses and successive hydrothermal stages, despite several similarities in geologic setting and country- and host-rock compositions. There was a transition from a post-collisional to a within-plate setting over about 20 Ma in Late Carboniferous-Early Permian times, with the older Żeleźniak and Bukowinka sub-volcanic intrusions in the uplifted part of the Kaczawa Metamorphic Complex (ZI) and the younger Wielisław Złotoryjski sub-volcanic intrusion in the metamorphic basement of an intramontane basin.
Źródło:
Annales Societatis Geologorum Poloniae; 2014, 84, 3; 213-233
0208-9068
Pojawia się w:
Annales Societatis Geologorum Poloniae
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
40Ar-39 Ar ages of selected rocks and minerals from the Kraków-Lubliniec Fault Zone, and their relation to the Paleozoic structural evolution of the Malopolska and Brunovistulian terranes (S Poland)
Autorzy:
Nawrocki, J.
Krzemiński, L.
Pańczyk, M.
Powiązania:
https://bibliotekanauki.pl/articles/2059087.pdf
Data publikacji:
2010
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
S Poland
late Paleozoic
palaeogeography
Ar-Ar geochronology
Opis:
New 40Ar-39 Ar isotope ages of mafic and felsic rocks from the contact zone of the Malopolska and Brunovistulian terranes are presented and discussed. A 40Ar-39 Ar age estimation of detrital muscovite from a Lower Devonian "old red" type sandstone drilled on the Malopolska side of this zone was also done. Our studies reveal that three events of Paleozoic magmatic activity took place in the study area. The oldest, late Emsian episode is recorded by a diorite from the core part of an intrusion penetrated by the Sosnowiec IG 1 borehole. A younger, Visean event is documented by a diabase cored in the borehole WB-137. Diabases from Niedwiedzia Góra and from borehole PZ-10, and a rhyodacite from borehole 16-WB gave early Permian (Artinskian-early Sakmarian) ages. The youngest, middle Sakmarian age was obtained for a diabase forming the external parts of the Sosnowiec IG 1 polycyclic intrusion. A diorite penetrated by the Sosnowiec IG 1 borehole was emplaced during the late Emsian extension that preceded the Lochkovian-Pragian? transpression related to the final docking and amalgamation of the Brunovistulian Terrane.
Źródło:
Geological Quarterly; 2010, 54, 3; 289-300
1641-7291
Pojawia się w:
Geological Quarterly
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:
A reappraisal of K-Ar and new U-Pb age data for felsic rocks in the vicinity of the Kraków-Lubliniec Fault Zone (southern Poland)
Autorzy:
Jarmołowicz-Szulc, Katarzyna
Powiązania:
https://bibliotekanauki.pl/articles/2060264.pdf
Data publikacji:
2020
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
magmatic rocks
zircon
geochronology
Kraków-Lubliniec Fault Zone
Opis:
New U-Pb zircon SHRIMP determinations from magmatic silicic rocks adjacent to the NE part of the Upper Silesia Coal Basin (USB) are provided and compared with earlier data obtained by K-Ar dating. The zircon samples studied came from the same boreholes and depth intervals previously sampled for K-Ar datings. Recalculations of the earlier K-Ar values for biotites yielded isochron ages in the range of 297-309 Ma. The zircon U-Pb SHRIMP values gave more precise ages between 300.1 ±1.2 Ma and 292.6 ±1.3 Ma (1б) consistent with U-Pb and Re-Os determinations. In two cases, the recalculated results of K-Ar dates were nearly identical with those obtained from the SHRIMP isotopic analyses. In this context, the granitoids and porphyries of the USB area, once assigned to the Carboniferous-Permian based on the older K-Ar studies, actually are of the same age as other felsic igneous rocks from the vicinity of the Kraków-Lubliniec Fault Zone, with a higher dating precision, however. The new data underline the importance of Late Carboniferous-Early Permian felsic magmatism at the SW margin of the Trans-European Suture Zone in southern Poland. In the zircon populations dated, besides the dominant Late Paleozoic ages, there are some inherited zircon cores, likely remnant detrital grains from a sediment component in the source rocks, that reveal much older ages which range from ~2051 to 569 Ma.
Źródło:
Geological Quarterly; 2020, 64, 3; 754--765
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Karst processes and time
Procesy krasowe a czas
Autorzy:
Bosak, Pavel
Powiązania:
https://bibliotekanauki.pl/articles/94511.pdf
Data publikacji:
2008
Wydawca:
Uniwersytet im. Adama Mickiewicza w Poznaniu
Tematy:
kras
speleogeneza
geochronologia
niezgodności
karst
speleogenesis
geochronology
unconformities
Opis:
Karst evolution depends particularly on the time available for process evolution and on the geographical and geological conditions of the exposure of the rock. The longer the time, the higher the hydraulic gradient and the larger the amount of solvent water entering the karst system, the more evolved is the karst. In general, stratigraphic discontinuities directly influence the intensity and extent of karstification. Unconformities influence the stratigraphy of the karst through the time-span that is available for subaerial processes. The end of karstification can also be viewed from various perspectives. The definite end occurs at the moment when the host rock, together with its karst phenomena, has completely been eroded/denuded. Karst forms of individual evolution stages (cycles) can also be destroyed by erosion, denudation and abrasion without the necessity of the destruction of the whole succession of karst rocks. Temporary and/or final interruption of the karstification process can be caused by the “fossilisation” of the existing karst phenomena due to loss of hydrological activity. The shorter the time available for karstification, the greater is the likelihood that karst phenomena are pre-served in the stratigraphic record. While products of short-lived karstification on shallow carbonate platforms can be preserved by deposition during a immediately succeeding sea-level rise, products of more pronounced karstification can be destroyed by various geomorphological processes. The longer the duration of subaerial exposure, the more complex these geomorphological agents are.
Rozwój procesów krasowych jest funkcją czasu oraz geograficznych i geologicznych warunków odsłonięcia skał. Im dłuższy czas ekspozycji skał na czynniki meteorologiczne, większy gradient hydrauliczny, większa ilość wody w układzie krasowym, tym bardziej zaawansowana jest ewolucja krasu. Intensywność i zasięg krasowienia zależą też od niezgodności stratygraficznych, czyli przerw w sedymentacji. Zakończenie rozwoju procesów krasowych rozpatrywać można w różnych kategoriach. Za definitywny koniec należy uznać czas, gdy skały podlegające krasowieniu ulegną całkowitej denudacji/erozji. O wiele częściej bywa, że zniszczeniu ulegają tylko formy krasowe, natomiast niżej położone skały systemu krasowego pozostają zachowane. Okresowe lub całkowite przerwanie procesów krasowych może być spowodowane przez fosylizację systemu krasowego, która zachodzi w efekcie zaniku aktywności hydrologicznej. Taka fosylizacja może być spowodowana przez metamorfizm, transgresję morską, pogrzebanie osadami kontynentalnymi lub skałami wulkanicznymi, w wyniku np. ruchów tektonicznych, zmiany klimatu, itp. Im krótszy jest czas krasowienia, tym większe jest prawdopodobieństwo zachowania śladów procesów krasowych. I tak, produkty krótkookresowej karstyfikacji na płytkich, okresowo wynurzanych platformach węglanowych mogą ulegać łatwemu zachowaniu poprzez pogrzebanie osadami deponowanymi podczas podniesienia poziomu morza. Natomiast efekty długotrwałego krasowienia bywają często niszczone przez późniejsze degradacyjne procesy geomorfologiczne. Charakter tych ostatnich jest tym bardziej skomplikowany, im dłużej trwa subaeralna ekspozycja skrasowiałych skał.
Źródło:
Geologos; 2008, 14, 1; 19-36
1426-8981
2080-6574
Pojawia się w:
Geologos
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Tournaisian 40Ar/39Ar age for alkaline basalts from the Lublin Basin (SE Poland)
Autorzy:
Pańczyk, M.
Nawrocki, J.
Powiązania:
https://bibliotekanauki.pl/articles/2059639.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
alkaline basaltic rocks
Ar-Ar geochronology
Carboniferous
Lublin Basin
Opis:
The main aim of this study is to define precisely the age of the alkaline basalts occurring within the lowermost part of Carboniferous succession in the northeastern part of LublinBasin(drill core Parczew IG-7 and IG-9; SE Poland). The new, whole-rocks 40Ar/39Ar data constrain the age of volcanic activity and emplacement of alkaline basalts to the Late Tournaisian (348 ± 0.8 Ma) with possible prolongation to the Middle Visean (338.5 ± 0.7 Ma). The younger age is however of evidently poorer quality than the older one. The new data caused to correlate the volcanic processes occurring within the Lublin Basin with alkaline intrusions drilled inNE Poland inside the Paleozoic cover of the East European Platform. They also correspond to the volcanoclastic levels defined in different parts of the Trans European Suture Zone in Poland.
Źródło:
Geological Quarterly; 2015, 59, 3; 473--478
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
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