scholarly journals Permian A-type rhyolites of the Muráň Nappe, Inner Western Carpathians, Slovakia: in-situ zircon U–Pb SIMS ages and tectonic setting

2018 ◽  
Vol 69 (2) ◽  
pp. 187-198 ◽  
Author(s):  
Martin Ondrejka ◽  
Xian-Hua Li ◽  
Rastislav Vojtko ◽  
Marian Putis ◽  
Pavel Uher ◽  
...  
Keyword(s):  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Western Carpathians ◽  
Magmatic Activity ◽  
Extensional Tectonics ◽  
Geochronological Data ◽  
Pb Isotope ◽  
Isotope Technique ◽  
Rhyolitic Rock

AbstractThree representative A-type rhyolitic rock samples from the Muráň Nappe of the inferred Silicic Unit of the Inner Western Carpathians (Slovakia) were dated using the high-precision SIMS U–Pb isotope technique on zircons. The geochronological data presented in this paper is the first in-situ isotopic dating of these volcanic rocks. Oscillatory zoned zircon crystals mostly revealed concordant Permian (Guadalupian) ages: 266.6 ± 2.4 Ma in Tisovec-Rejkovo (TIS-1), 263.3 ± 1.9 Ma in Telgárt-Gregová Hill (TEL-1) and 269.5 ± 1.8 Ma in Veľká Stožka-Dudlavka (SD-2) rhyolites. The results indicate that the formation of A-type rhyolites and their plutonic equivalents are connected to magmatic activity during the Permian extensional tectonics and most likely related to the Pangea supercontinent break-up.

U–Pb and Re–Os geochronology of the Haolibao porphyry Mo–Cu deposit, NE China: implications for a Late Permian tectonic setting

2013 ◽  
Vol 150 (6) ◽  
pp. 975-985 ◽  
Author(s):  
QING-DONG ZENG ◽  
YAN SUN ◽  
XIAO-XIA DUAN ◽  
JIAN-MING LIU
Keyword(s):  
North China ◽  
Tectonic Setting ◽  
Magmatic Activity ◽  
Late Permian ◽  
Ne China ◽  
Geochronological Data ◽  
The North ◽  
Intrusive Rocks ◽  
North China Plate ◽  
Age Determinations

AbstractNew geochronological data for the Haolibao porphyry Mo–Cu deposit, NE China, yield Permian crystallization zircon U–Pb ages of 278 ± 5 Ma for granite and 267 ± 10 Ma for the granite porphyry that hosts the Mo–Cu mineralization, and four Re–Os molybdenite ages yield an isochron age of 265 ± 3 Ma. These ages disagree with the previous K–Ar age determinations that suggest a correlation of intrusive rocks of the Haolibao area with the Yanshanian intrusive rocks of Cretaceous age. The mineralizations at the Haolibao area may be related to the tectonic–magmatic activity caused by collisional events between the North China Plate and Mongolian terranes during the Permian. The occurrence of the Haolibao plutonic rocks indicates that the Palaeo-Asian-Mongolian Ocean closed during the Permian along the Xilamulun River suture.

Metallogenic significance of trace element and U–Pb isotope data for uraninite-rich mineral separates from the Labrador Central Mineral Belt

1993 ◽  
Vol 30 (12) ◽  
pp. 2352-2365 ◽  
Author(s):  
Derek H. C. Wilton ◽  
Henry P. Longerich
Keyword(s):  
Inductively Coupled Plasma ◽  
Genetic Relationships ◽  
Volcanic Rocks ◽  
Analytical Techniques ◽  
Geochronological Data ◽  
Pb Isotope ◽  
Isotope Data ◽  
Mineral Belt ◽  
Felsic Volcanic ◽  
Host Rocks

Thirteen concentrates of uraniferous material were prepared from uranium occurrences in the Central Mineral Belt of Labrador. Host rocks to these occurrences include granitoid rocks of the Archean basement, ca. 2000 Ma metasedimentary rocks of the Lower Aillik Group, and 1860 Ma felsic volcanic rocks of the Upper Aillik Group. Common lead corrected Pb isotope data from inductively coupled plasma mass spectrometry analyses define 207Pb/206Pb ages ranging from 1805 to 1697 Ma for all but one sample, with a mean age of 1752 ± 27 Ma (1 σ). Ages calculated for individual samples are similar to those derived by previous workers using standard analytical techniques. Eleven of these samples define linear trends that intersect the U–Pb concordia at 1741 ± 23 Ma and a Tera-Wasserburg curve at 1740 ± 21 Ma, respectively. These data suggest that the occurrences are epigenetic with respect to host rocks and possibly related to a common metallogenic event, therefore resolving a long-standing controversy about the timing and mode of occurrence of the widespread uranium mineralization in this part of the belt. These ages broadly correlate with a period of migmatization, metamorphism, and granitoid plutonism, as defined by U–Pb zircon geochronological data for regional units. Rare earth element data for uraninite from all concentrates resemble those of uraninite in granite-related deposits. One sample has a distinctly different calculated 207Pb/206Pb age of 495 Ma, indicative of a later remobilization of the ca. 1741 Ma mineralization. The geochemical and geochronological data collectively suggest that the Central Mineral Belt uranium occurrences were related to posttectonic granite magmatism and have no direct genetic relationships with nongranitoid host rocks.

scholarly journals Study of the mineralization potential of the intrusives around Valis (Tarom-Iran)

2015 ◽  
Vol 18 (2) ◽  
pp. 123-129 ◽  
Author(s):  
Mojtaba Bahajroy ◽  
Saeed Taki
Keyword(s):  
Tectonic Setting ◽  
Volcanic Rocks ◽  
Central Iran ◽  
Lava Flows ◽  
Magmatic Activity ◽  
Petrographic Composition ◽  
Molar Ratios ◽  
Exposed Rock ◽  
Metallogenic Zone ◽  
Northwestern Iran

<p>The study area is located in northwestern Iran in the central Iran zone, specifically the western Alborz sub-zone south of the Tarom-Hashtjin metallogenic zone. The exposed rock units in this area generally include Eocene volcanic rocks (lava flows and pyroclasts belonging to the Karaj formation) and Oligocene granitoid intrusive bodies. The intrusive bodies in the area have a petrographic composition of granite, syenite and monzonite and are mostly metaluminous. The dual characteristics of these intrusives (for example, the behavior of elements such as Rb, P, Ga/Al, Y/Nb, K/Na, and FeO/Fe2O3, the Rb/Nb ratios, the A/CNK molar ratios and the ACF and A/CNK-Fe2O3+FeO diagrams), some of which are consistent with the I nature and others with the S and A natures, show that the rocks are among hybrid granitoids and, in terms of the tectonic setting, lie within the WPG range. According to the Rb/Sr, Zr/Hf, K/Rb ratios, the granite melts that form the aforementioned bodies are not extremely evolved and have not undergone post magmatic activity, which would lead to mineralization. The Sm/Eu and Rb/Ba ratios and the behavior of Rb, Ba and Sr within the aforementioned granitoids show that the rocks are similar to average granitoids unrelated to Li, Be, Sn, W and Ta deposits; they fall within the range of barren granitoids but are partially fertile in Cu.</p><p> </p><p><strong>Resumen</strong></p><p>El área de este estudio está localizada en el noroeste de la zona central de Irán, específicamente en el oeste de la subzona de Alborz y al sur de la zona metalogénica de Tarom-Hashtjin. Las unidades de roca expuesta en esta área se clasifican generalmente como rocas volcánicas del Eoceno (flujos de lava y piroclastos pertenecientes a la formación Karaj) y como cuerpos granitoides intrusivos del Oligoceno. Los cuerpos intrusivos en el  área tienen una composición petrográfica de granito, sienita y monzonita mayormente metaluminosa. Las  características duales de estas intrusiones (por ejemplo, el comportamiento de de elementos como Rb, P, Ga/ Al, Y/Nb, K/Na, y Feo/Fe2O3, los índice de Rb/Nb, la proporción molar de los A/CNK y los diagramas ACF y A/CNK-Fe2O3+FeO), algunas de las cuales son consistentes con la índole I y otras con las índoles S y A, muestran que las rocas son granitoides híbridos y, en términos de orden tectónico, subyacen en la cadena WPG. De acuerdo con los índices Rb/Sr, Zr/Hf, K/Rb, los granitos fundieron la forma de los cuerpos sin desarrollarse completamente y sin registrar actividad magmática posterior, lo que llevó a la mineralización. Los índices Sm/Eu y Rb/Ba y el comportamiento del Rb, Ba y Sr al interior de los granitoides mencionados muestran que las rocas son similares al promedio de los granitoides no relacionados con los depósitos de Li, Be, Sn, W y Ta; estos incluyen en el rango de granitoides estériles, pero son parcialemente fértiles en Cu.</p><p><strong><br /></strong></p>

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