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Tytuł:
Constraints on the nature and evolution of the volcanic fields of the Andahua Group, Central Volcanic Zone, southern Peru
Autorzy:
Gałaś, Andrzej
Németh, Károly
Lewińska, Paulina
Powiązania:
https://bibliotekanauki.pl/articles/2201223.pdf
Data publikacji:
2022
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
monogenetic volcanoes
small lava dome
petrological modelling
Andes
Opis:
The Andahua Group is a distinct cluster of typically monogenetic volcanoes located in the northernmost part of the Central Volcanic Zone in the Andes, characterized by small-volume lava domes and scoria cones. Seven volcanic clusters have been distinguished. Using satellite imagery, geological mapping, and fieldwork, we found a total of 103 lava domes, 43 scoria cones, and 3 small composite volcanoes. Most of the lava domes are monogenetic but 9 were formed by multiple eruptions. Petrogenetic models have been developed for the magma evolution of the Andahua Group. They show local crustal influence on the magmas generated, and possible controls on the magma pathway to the surface, and potential segregation. Local compositional variation of the crustal rocks is inferred to have a strong influence on the magma that ascends through the thick continental crust. Assimilation and contamination by deeply seated granitoids of the Arequipa and Paracas massifs are also inferred to play a role in the final magmatic products. Future activity with gas emissions from the Andahua Group volcanoes may cause hazardous conditions for tourists.
Źródło:
Geological Quarterly; 2022, 66, 3; art. no. 25
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Model przestrzenny struktury solnej Inowrocław a wizualizacja przemieszczeń powierzchni terenu zarejestrowanych na podstawie badań interferometrycznych
Application of the spatial model of the Inowrocław salt structure for clarification and visualization of surface movements registered by inter- ferometric investigation
Autorzy:
Piątkowska, A.
Czuryłowicz, K.
Przyłucka, M.
Powiązania:
https://bibliotekanauki.pl/articles/2075123.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
salt dome
interferometry
spatial model
wysad solny
interferometria
model przestrzenny
Opis:
The Inowrocław salt dome can be considered one of the model structures in the Polish Lowlands. Salt structures formed as the result of halotectonic and halokinetic action. The Permian salt was squeezed upwards from deep geological levels due to the overburden load, using fractured zon es and faults. The salt dome is presented as a dynamie three- A Piątkowska K Czuryłowicz M Przyłucka -dimensional geological model developed using advanced technology to create and visualize 3D spatial data. Thanks to the relationship between the dynamics of the land surface and natural geological processes, the results and conclusions can be quickly drawn. For this purpose, average values of displacements in mm peryear, obtained by Satellite Radar Interferometry - Persistent Scatterers (PS) for the time span 1992-2006, are presented in the form of interpolation, creating a surface ofground movement (subsidence and uplift) above the Inowrocław salt dome.
Źródło:
Przegląd Geologiczny; 2014, 62, 2; 97--102
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Oxygen and sulphur isotopes of gypsum from the Mogilno Salt Dome cap-rock (Central Poland)
Autorzy:
Jaworska, J. K
Wilkosz, P.
Powiązania:
https://bibliotekanauki.pl/articles/2059001.pdf
Data publikacji:
2012
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
gypsum
oxygen isotopes
sulphur isotopes
cap-rock
Mogilno Salt Dome
Opis:
The stable-isotope compositions of oxygen and sulphur from 30 gypsum samples obtained from three drill cores of the Mogilno Salt Dome cap-rock have been analysed; the Mogilno Salt Dome itself is composed of Zechstein evaporites. d344 184242418344182418181818218218218218182
Źródło:
Geological Quarterly; 2012, 56, 2; 249-260
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An oxygen and sulfur isotopic study of gypsumfrom the Wapno Salt Dome cap-rock (Poland)
Autorzy:
Jaworska, J.
Powiązania:
https://bibliotekanauki.pl/articles/2059040.pdf
Data publikacji:
2010
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
Wapno Salt Dome
cap-rock
gypsum
oxygen and sulfur isotopes
Opis:
The stable isotope compositions of oxygen and sulfur from gypsum samples derived from borehole cores of the Wapno Salt Domecap-rock have been determined. The d18O values were measured (for both the SO4 and the H2O) in bulk samples of gypsum(CaSO4 2H2O) and in its dehydrated equivalents (CaSO4). The SO4 is enriched in the heavy oxygen isotope, which unequivocally indicates the Zechstein sea as the place of origin of the sulfate. The variable δ18O values of the H2O (water of crystallization) indicate different conditions (and stages) of diagenetic processes of these samples, primarily recrystallization (hydration) episodes. Two groups ofgypsum were distinguished: (1) a group in which the δ18O values of H2O range between -9.0 and -10.2‰ (interpreted as gypsum in equilibrium with recent or subrecent meteoric water), (2) a group in which the d18O values of the H2O were less than -10.2‰ (this gypsum hasrecrystallized in the presence of water enriched in the light isotopes of oxygen). In addition, in one single analysis the δ18O value of the H>sub>2O amounts to -5.6‰ (gypsum with mixed isotopic composition).
Źródło:
Geological Quarterly; 2010, 54, 1; 25-32
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Phase transitions in the borate minerals from the Kłodawa Salt Dome (Central Poland) as the indicators of the temperature processes in salt diapirs
Autorzy:
Wachowiak, J.
Toboła, T.
Powiązania:
https://bibliotekanauki.pl/articles/2060065.pdf
Data publikacji:
2014
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
boracite
congolite
phase transitions
temperature study
Zechstein
salt dome
Kłodawa
Polska
Opis:
The diapiric structures of the Polish Lowlands are tectonically deeply seated down to the autochthonous Zechstein strata at a depth of ca. 6 km. In the process of deep burial and halokinetic diapirism, the salt rocks were subjected to diagenetic and metamorphic transformations, with the temperature being an essential factor. Considering the thermal gradient, a temperature of up to ca. 200°C can be achieved in the salt dome within a depth range from several hundred metres to 6 km, which may lead to transformations of the majority of salt minerals. Phase transitions of two borate minerals – boracite and congolite from the Kłodawa salt dome – provide evidence for higher temperatures in the salt dome rocks. The authigenic euhedral crystals of those borate minerals display their external habitus in ambient temperature in the form of regular symmetry (F43c – pseudo-regular polyhedrons), whereas their internal structure is lower: orthorhombic (Pca21) for boracite and rhombohedral (R3C) for congolite. The heating and cooling of boracite and congolite crystals show reversible phase transition. At a temperature of ca. 270°C, boracite crystals change their symmetry: orthorhombic ↔ cubic. In the case of congolite three reversible phase transitions within a temperature range of 50–339°C can be observed: rhombohedral ↔ monoclinic ↔ orthorhombic ↔ cubic symmetry. Those phase transitions, confirmed experimentally in our study, clearly document at least local occurrences of temperatures exceeding 339°C in the Kłodawa salt dome.
Źródło:
Geological Quarterly; 2014, 58, 3; 543--554
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Palaeoecologic significance of the Callovian-Oxfordian trace fossils of Gangeshwar Dome, Southeast of Bhuj, Mainland Kachchh, India
Autorzy:
Bhatt, N. Y.
Patel, S. J.
Powiązania:
https://bibliotekanauki.pl/articles/2060982.pdf
Data publikacji:
2017
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
trace fossils
Gangeshwar Dome
Mainland Kachchh
India
Late-Middle Jurassic
ichnocoenoses
skamieniałości śladowe
Indie
Opis:
The shallow marine deposits of the Late-Middle Jurassic (Callovian–Oxfordian) Jumara Formation of the Gangeshwar Dome of Mainland Kachchh, India, comprise a succession of ~247 m thick clastic sediments with few non-clastic bands and contain a diverse group of ichnofauna. The succession is subdivided into seven lithofacies, viz., laminated shale-siltstone facies (LSS), sheet sandstone facies (SS), herringbone sandstone facies (HS), bivalve sandstone facies (BS), bioclastic limestone facies (BL), intraformational conglomerate facies (IC) and oolitic limestone facies (OL). The ichnofaunal study shows 29 ichnospecies of 23 ichnogenera including Arenicolites, Bifungites, Bolonia, Chondrites, Didymaulichnus, Diplocraterion, Gyrochorte, Helminthopsis, Isopodichnus, Laevicyclus, Lockeia, Monocraterion, Taenidium, Ophiomorpha, Palaeophycus, Planolites, Phycodes, Protopalaeodictyon, Rhizocorallium, Skolithos, Thalassinoides, Tisoa, and Zoophycos. These trace fossils are distributed among nine ichnocoenose, characterized by Chondrites, Diplocraterion, Gyrochorte, Ophiomorpha, Rhizocorallium, Skolithos, Taenidium, Thalassinoides and Zoophycos. Their occurrence in the facies corresponds to their trophic and ethological properties. The colonisation of the opportunistic Diplocraterion and the Skolithos ichnocoenose shows a high den¬sity and marks foreshore/nearshore environmental conditions. The Gyrochorte, the Rhizocorallium, the Taenidium and the Thalassinoides ichnocoenose indicate the typically lower energy zone of the shoreface-offshore region. The Chondrites ichnocoenosis indicates fluctuation in bottom water oxygen while the Zoophycos ichnocoenosis typically exploited a calm water niche in the offshore region. These ich-nocoenose recur throughout the sequence and belong to the Skolithos and the Cruziana ichnofacies which marked changes in energy gradient, substrate stability, water depth and mode of life of invertebrate organisms. The study of trace fossil assemblages with sediment characteristics gives a detailed and accurate picture of foreshore to offshore palaeoenvironmental conditions.
Źródło:
Volumina Jurassica; 2017, 15, 1; 17--40
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monazite Th-U-total Pb geochronology and P-T thermodynamic modelling in a revision of the HP-HT metamorphic record in granulites from Stary Gierałtów (NE Orlica-Śnieżnik Dome, SW Poland)
Autorzy:
Budzyń, B.
Jastrzębski, M.
Kozub-Budzyń, G. A.
Konečný, P.
Powiązania:
https://bibliotekanauki.pl/articles/2060006.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
monazite
Th-U-total Pb dating
thermodynamic modelling
granulite
Orlica-Śnieżnik Dome
Bohemian Massif
Opis:
Thermodynamic modelling and monazite Th-U-total Pb dating via electron microprobe were used to improve the pressure, temperature and timing constraints of the HP-HT metamorphic record in granulites from Stary Gierałtów (NE Orlica-Śnieżnik Dome (OSD), SW Poland). The thermodynamic calculations constrained the P-T conditions to 20-22 kbar and ca. 920ºC in the felsic to intermediate granulites and 20-22 kbar and ca. 970ºC in the mafic granulite. These conditions are considered to closely represent the peak temperatures experienced by these rocks. In the intermediate granulite, the matrix monazite and monazite inclusions in garnet and allanite yielded an age of 349±2.5 Ma. An HP-HT metamorphic event with temperature conditions exceeding 900ºC, which are greater than the closure temperatures of most geochronometers, must have disturbed and completely reset the isotopic systems, including the Th-U-Pb system in the monazite. Consequently, this resetting prevented us from constraining the age of potential earlier metamorphic events or the igneous protolith. The 349±2.5 Ma age reflects the timing of the late-stage HP-HT event and cooling below 900ºC related to the initial exhumation of the granulites. A comparison of the new P-T-t constraints with previous data from the NE Orlica-Śnieżnik Dome indicates that the activation of the channels that exhumed the HP rocks to mid-crustal depths most likely initiated at ca. 350 Ma, and all the metamorphic rocks in the OSD likely shared a common Variscan evolution after ca. 340 Ma.
Źródło:
Geological Quarterly; 2015, 59, 4; 700--717
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Facies and diagenetic evolution of the Bathonian-Oxfordian mixed siliciclastic-carbonate sediments of the Habo Dome, Kachchh Basin, India
Autorzy:
Ahmad, A. H. M.
Irshad, R.
Bhat, G. M.
Powiązania:
https://bibliotekanauki.pl/articles/2077322.pdf
Data publikacji:
2015
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
facies
diagenetic evolution
Habo Dome
Kachchh Basin
India
facja
diageneza
ewolucja diagenetyczna
Kachchh
Indie
Opis:
This paper examines the depositional environment and diagenetic aspects of the exposed Patcham and Chari formation within the Habo Dome. The Patcham Formation is represented by the Black Limestone Member. The Chari Formation is represented by two distinct sedimentary successions: (i) shale and carbonates, and (ii) coarse clastics. The paper describes eleven lithofacies from these successions. The depositional framework constituents of these facies have been greatly modified by diagenetic evolution through time. Two main depositional environments, i.e. foreshore intertidal and shoreface (subtidal), have dominated during their deposition. The diagenetic signatures observed within these sediments suggest early or syndepositional changes in marine phreatic and burial environments. Two phases of early mechanical compaction have largely governed porosity evolution within the limestone facies. Micritization of the allochems was caused by endolithic algae prevalent within the restricted lagoon environments with stagnant marine phreatic zone conditions. Random dissolution of microcrystalline grains has created vugs with patchy distribution reflecting neomorphism within the meteoric vadose zone. The types of cements within the sandstone facies include silica, calcite, and its replacement by Fe-calcite cement. The sandstones were deposited in a relatively low energy environment below storm wave base. The depositional conditions have controlled the early diagenesis of the sandstones which in turn have influenced their burial diagenesis.
Źródło:
Volumina Jurassica; 2015, 13, 1; 83--104
1896-7876
1731-3708
Pojawia się w:
Volumina Jurassica
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Wyznaczanie kształtu ścian bocznych wysadów solnych metodą tomografii sejsmicznej na przykładzie wysadu "Góra"
Shape estimation of the salt domesside walls with seismic tomography- a salt dome "Góra" case study
Autorzy:
Krynicki, T.
Mieszkowski, R
Wojas, A.
Powiązania:
https://bibliotekanauki.pl/articles/2074359.pdf
Data publikacji:
2005
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
tomografia sejsmiczna
wysad solny
obraz falowy
seismic tomography
salt dome
storage of gas
wave picture
Opis:
Salt Dome “Góra” was studied with seismic tomography method. Three profiles are described. The interpretation of wave pictures helped to locate the walls of the studied salt dome’s. The research confirmed the salt dome has good properties for storage of gas or toxic and radioactive wastes.
Źródło:
Przegląd Geologiczny; 2005, 53, 8; 695--698
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Utwory pogranicza cyklotemów PZ1 i PZ2 cechsztynu w kłodawskim wysadzie solnym (środkowa Polska)
Deposits from the transition of Zechstein PZ1 to PZ2 cyclothems in the Kłodawa salt dome (central Poland)
Autorzy:
Czapowski, G.
Tomassi-Morawiec, H.
Powiązania:
https://bibliotekanauki.pl/articles/2075825.pdf
Data publikacji:
2018
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
ewaporaty
brom
cechsztyn
kłodawski wysad solny
Polska centralna
evaporites
bromine
Zechstein
Kłodawa salt dome
Central Poland
Opis:
The possible occurrence of the Oldest Halite (Na1) unit of the Zechstein PZ1 cyclothem in the Kłodawa salt dome was a discussed matter for many years. Profiling and sampling of the evaporite Zechstein succession (a transition of PZ1 to PZ2 cyclothems) visible in a corridor of the "Kłodawa” Salt Mine at the mining level -650 m, located near the NE marginal pillar of the dome, were done in 2011. The studied section includes rock salt, shale, sulphate and carbonate rocks inclined at 60-90o to the NE and represents a normal succession of the PZ1 and PZ2 cyclothems. The normal succession of the top part of the PZ1 cyclothem consists of two lithological units: 1) rock salt complex (extending over a distance of ca. 5.8 m), defined as the Oldest Halite (Na1) lithostratigraphic unit, and 2) anhydrite bed, c.a. 1.3 m thick, distinguished as the Upper Anhydrite (A1g). These deposits are overlain by 4 lithological units, considered as those creating the normal sequence of the lower part of the younger PZ2 cyclothem. The first one is a dolomitic shale bed, ca. 3.7 m thick, defined as the Stink Shale (T2). It is overlain by a dolomite layer, 0.3-0.5 m thick, representing the Main Dolomite (Ca2), and by an anhydrite series, over 17 m thick, attributed to the Basal Anhydrite (A2). The studied section ends with a rock salt complex, ca. 4 m thick, interpreted as the Older Halite (Na2). The bromine (Br) content in both salt units is relatively low: 81-86 ppm (7 samples) in the Na1 unit and 54-77 ppm (4 samples) in the Na2 unit, with a distinct upward-increasing trend in the latter. Similar low Br values and their distribution trends were characteristic for the top of the Na1 standard bromine curve in Poland and for the lower part of such curve for the Na2 salts. This geochemical similarity could support a proper stratigraphic position of both units. The analysed section was interpreted as a tectonic slice or intrusion, composed of Na1 rock salt overlain with the younger A1g sulphate, incorporated within the folded complex of Na2 rock salt. Such image confirms the current opinion of a more complicated internal structure of the so-called "marginal anticlines” within the Kłodawa dome, composed of intensively folded both salt units. It also documents that the oldest Zechstein evaporites (chlorides and sulphates) could occur above within the dome section than was stated earlier.
Źródło:
Przegląd Geologiczny; 2018, 66, 5; 303--308
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Współczesne ruchy wysadu solnego Inowrocławia w świetle badań geodezyjnych
Contemporary movements of the Inowrocław Salt Dome in the light of geodetic surveys
Autorzy:
Szczerbowski, Zbigniew
Gawałkiewicz, Rafał
Powiązania:
https://bibliotekanauki.pl/articles/2076109.pdf
Data publikacji:
2020
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
wysad solny
ruchy wysadu
niwelacja
odkształcenia górnicze
subrozja
salt dome
diapir movements
levelling
mining deformations
subrosion
Opis:
The paper presents results of long-standing geodetic measurements including the most recent results of levelling measurements carried out by the authors. Based on the results, a model of ground surface movements was created, which roughly reflects contemporary tectonic activity of the Inowrocław salt structure. The performance of vertical displacements of benchmarks of the research network for the last quarter-century shows its significant mobility. The results of measurements were discussed in the context of the state of art of tectonic mobility of the area and the geological structure of the dome. Unusual agreement in rates of geological processes (salt diapir uplift) determined by geodetic measurements and estimated by geological methods for a long time interval confirms trueness of previous ideas about contemporary diapir movements of the Inowrocław Salt Dome. Repeated levelling evaluated for two last time intervals provided similar regions and rates of uplifts, giving additional control of reliability of the measurements.
Źródło:
Przegląd Geologiczny; 2020, 68, 3; 195--203
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Pochodzenie stylolitów w gipsach z czapy wysadu solnego Wapna
Origin of stylolites in gypsum cap rock of Wapno Salt Dome (NW Poland)
Autorzy:
Jaworska, J.
Powiązania:
https://bibliotekanauki.pl/articles/2074477.pdf
Data publikacji:
2006
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
stylolit
czapa gipsowa
wysad solny
stylolites
evaporates
gypsum cap rock
Zechstein
detached block
Wapno Salt Dome
Opis:
Stylolites have been found in a core sample from the gypsum cap rock of the Wapno salt dome (figs 1-3) at a depth of 40 m below the land surface. These structures are inclined at 40-45ş to the core axis and cut by neomorphic gypsum crystals. Stylolites are products of the solution pressure. They commonly occur in carbonates but are very rarely encountered in evaporates, thus the origin and preservation of these structures in the cap rock of Wapno dome are interesting problems. Lithostatic pressure near the surface where the cap rock has been formed is insufficient to develop stylolites. Thus stylolites (fFigs 4-5) in gypsum cap rock of the Wapno salt diapir are probably early diagenetic structures preserved in a fragment of Zechstein anhydrite of Z2 or Z3 cyclothems. This anhydrite block with stylolites have been carried inside intruding salt masses to the top ofWapno dome. Halite and other easy soluble minerals had been dissolved, but the anhydrites with preserved stylolites have been incorporated in the cap rock and secondary altered into gypsum, similarly to the phenomenon found in Gorleben Salt Dome by Bäuerle et al. (2000).
Źródło:
Przegląd Geologiczny; 2006, 54, 2; 166-169
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Karłowate wulkany formacji Andahua w południowym Peru
Dwarf volcanoes of Andahua Formation in South Peru
Autorzy:
Gałaś, A.
Paulo, A.
Powiązania:
https://bibliotekanauki.pl/articles/2074409.pdf
Data publikacji:
2005
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
formacja Andahua
strumień lawy
kopuła wulkaniczna
wulkan karłowaty
Peru
lava flow
lava dome
pyroclastic cone
Andahua formation
Opis:
In July 2003 and 2004 small groups of geologists of AGH — The University of Science and Technology in Kraków investigated recent Andahua volcanic formation of Southern Peru. It was identified first some 45 years ago but its extension is not definitely determined yet. Field work resulted in discovery of about 100 individual emission centres: apparent pyroclastic cones 50–300 metres high, and usually smaller lava domes and vents by controlled fractures. Morphology of the Andahua lava flows coalescing into composite lava fields as well as criteria for their stratigraphy and tectonic controls are given.
Źródło:
Przegląd Geologiczny; 2005, 53, 4; 320--326
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Monazite stability and the maintenance of Th-U-total Pb ages during post-magmatic processes in granitoids and host metasedimentary rocks: A case study from the Sudetes (SW Poland)
Autorzy:
Budzyń, B.
Jastrzębski, M.
Powiązania:
https://bibliotekanauki.pl/articles/2060191.pdf
Data publikacji:
2016
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
monazite stability
Th-U-total Pb dating
Jawornik granitoids
Kłodzko–Złoty Stok Pluton
Orlica-Śnieżnik Dome
Bohemian Massif
Opis:
The stability and maintenance of the age record of monazite during post-magmatic processes were studied in granitic and host metasedimentary rocks from the Sudetes (SW Poland). Unaltered monazite in the Kłodzko–Złoty Stok granitoid provided a Th-U-total Pb age of 329 ± 5 Ma, which was related to the late stage of pluton emplacement. In contrast, monazite in the Jawornik granitoid remained unaltered or was partially replaced by secondary phases, including (1) allanite, epidote and, occasionally, apatite; (2) cheralite, allanite and a mixture of clays, Fe oxides and possible unknown rare earth element (REE) phases; and (3) K-feldspar and cheralite with subsequent formation of titanite. Different alteration products on the thin section scale indicate the local character of the post-magmatic processes affecting monazite induced by alkali-rich fluids. The altered and unaltered monazite grains both yielded a Th-U-total Pb age of 343 ± 4 Ma. The Th-U-total Pb ages of the monazite in the accompanying metasedimentary rocks thermally affected by intruding magmas were also constrained. In the paragneiss in contact with the Jawornik granitoid, the unaltered monazite and monazite partially replaced by allanite yielded an age of 344 ± 5 Ma. The monazite from the mica schist, farther from the contact with the granitoids, exhibited an age of 336 ± 4.5 Ma. The 344–336 Ma ages exhibited a record of monazite (re)growth during prolonged Variscan metamorphism. The predominant early Viséan ages constrain the timing of the development of the Złoty Stok Skrzynka Shear Zone and the emplacement of the Jawornik granitoid intrusion. The age results, which are consistent with previous geochronology, indicate that the partial alteration of the monazite did not affect the internal domains or the maintenance of the monazite ages. Thus, this study reveals that monazite geochronology can provide meaningful data in crystalline rocks affected by fluid-induced post-magmatic processes.
Źródło:
Geological Quarterly; 2016, 60, 1; 106--123
1641-7291
Pojawia się w:
Geological Quarterly
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Struktury hydratacyjne i deformacyjne w skałach czapy gipsowej wysadu solnego Dębiny w rowie Kleszczowa
Deformation and hydrational structures in cap rocks of the Dębina Salt Dome, the Kleszczów Graben, central Poland
Autorzy:
Krzesińska, A.
Redlińska-Marczyńska, A.
Wilkosz, P.
Żelaźniewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/2074779.pdf
Data publikacji:
2010
Wydawca:
Państwowy Instytut Geologiczny – Państwowy Instytut Badawczy
Tematy:
wysad solny Dębiny
czapa skalna
gips
stylolity
strefa ścinania
rekrystalizacja
Dębina Salt Dome
cap rock
gypsum
stylolites
shear zones
recrystallization
Opis:
The Dębina salt dome is situated in central part of the Tertiary Kleszczów Graben, central Poland. Cap rocks of the dome were characterized on the basis of analysis of core material from a well drilled in the northern part of that structure. The cap rock sequence may be subdivided into two parts. Its lower part with breciated structure represents residuum from dissolution of saline series whereas the upper comprises rocks developed by coalescence of shale cover with gypsum. Gypsum rocks of the cap form 6 lithotypes. In these lithotypes it is possible to distinguish: 1) recrystallizational structures developed during diagenesis and multiple hydration transformations, 2) structures developed in a local stress field related to displacements evoked by dissolution of the cap rocks and fluid circulation. Structures of the first type include microcrystalline gypsum with anhydrite relics and carbonate nodules, lenticular and acicular gypsum, porphyroblastic and even-grained gypsum as well as vein gypsum and first generation of stylolites. The other type of structures is represented by: gypsum showing shape fabrics and associated gypsum nodules, gypsum grains with geometry of -clasts, fibrous gypsum in pressure shadows, structures of the core-and-mantle type, subgrains developing in bigger crystals and second generation of stylolites and slickolites. Five sets of fractures were recorded. These fractures developed in the cape rocks under stress field with the vertical maximum stress axis and active shear planes. The normal faults of B, C and D sets could be formed during upward motion of the dome, its stagnation, or during gravitational collapse triggered by karst processes. Oblique striations on microfault B surfaces point to later reactivation under local normal-slip regime caused by ongoing subsidence of the cap rocks, or alternatively - a reactivation that occurred in response to external stress field which controlled evolution of the extensional Kleszczów Graben.
Źródło:
Przegląd Geologiczny; 2010, 58, 6; 522-530
0033-2151
Pojawia się w:
Przegląd Geologiczny
Dostawca treści:
Biblioteka Nauki
Artykuł

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