scholarly journals Petrology and dating of the Permian lamprophyres from the Malá Fatra Mts. (Western Carpathians, Slovakia)

2018 ◽  
Vol 69 (5) ◽  
pp. 453-466 ◽  
Author(s):  
Ján Spišiak ◽  
Lucia Vetráková ◽  
David Chew ◽  
Štefan Ferenc ◽  
Tomáš Mikuš ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Granitic Rocks ◽  
Western Carpathians ◽  
Magma Ascent ◽  
Crustal Material ◽  
Calc Alkaline ◽  
Nd Isotopes ◽  
Granitoid Rocks ◽  
Alkaline Lamprophyres

Abstract Calc–alkaline lamprophyres are known from several localities in the Malá Fatra Mountains. They form dykes (0.5–3 m) of varying degree of alteration that have intruded the surrounding granitoid rocks which are often incorporated xenoliths. Clinopyroxenes (diopside to augite), amphiboles (kaersutitic), biotites (annite) and plagioclases are major primary minerals of the dykes, accessory minerals include apatite, ilmenite, rutile, pyrite, chalcopyrite, and pyrrhotite. Apatite has a relatively low F, but increased Cl content compared to typical apatite from lamprophyres or magmatic apatite from granitic rocks in the Western Carpathians. The chemical composition of the lamprophyres indicates their calc–alkaline character, but affinity to alkaline lamprophyres is suggested by the Ti enrichment in clinopyroxene, amphibole and biotite. According to modal classification of the minerals, the studied rocks correspond to spessartite. The differences in the chemical composition of the rocks (including Sr and Nd isotopes) probably result from the contamination of primary magma by crustal material during magma ascent. The age of the lamprophyres, based on U/Pb dating in apatite, is 263.4 ± 2.6 Ma.

Permian lamprophyres from the Western Carpathians: a review

2021 ◽  
pp. SP513-2020-237
Author(s):  
Ján Spišiak ◽  
Lucia Vetráková ◽  
David Chew ◽  
Štefan Ferenc ◽  
Viera Šimonová ◽  
...  
Keyword(s):  
Hydrothermal Fluid ◽  
Mineralogical Composition ◽  
Western Carpathians ◽  
Crustal Material ◽  
Calc Alkaline ◽  
Geochemical Composition ◽  
Nd Isotope ◽  
Icp Ms ◽  
Compositional Variations ◽  
Alkaline Lamprophyres

AbstractCalc-alkaline lamprophyres from the Western Carpathians occur as dykes and sills in the crystalline complexes (predominantly granites and gneisses) of the Tatric Unit. Some of the lamprophyre dykes have been strongly overprinted by tectonism and hydrothermal fluid ingress. They have a similar mineralogical composition, and they are comprised of clinopyroxene, amphibole, biotite and plagioclase. Based on their modal composition, they can be classified as spessartites and kersantites, and based on their geochemical composition, most of them are of calc-alkali type. Lamprophyres from individual core complexes (e.g. the Malá Fatra Mountains and Nízke Tatry Mountains) exhibit variable Nb, Ta and Sr–Nd isotope signatures. These differences are probably due to compositional variations in the mantle source and/or the lower crust at the site of lamprophyre melt generation, or variable incorporation of crustal material. The age of the lamprophyres is Permian (c. 265 Ma) based on U–Pb LA-ICP-MS dating of apatite micro-phenocrysts.

scholarly journals Petrology of the Doda Granites, Jammu Lesser Himalaya, India

1996 ◽  
Vol 14 ◽  
Author(s):  
B. L. Dhar ◽  
A. K. Raina ◽  
B. K. Fotedar ◽  
R. Singh
Keyword(s):  
Partial Melting ◽  
Granitic Rocks ◽  
Crustal Material ◽  
Lesser Himalaya ◽  
Calc Alkaline ◽  
Nw Himalaya ◽  
Jammu And Kashmir ◽  
Lower Crustal ◽  
Highly Evolved

Granitic rocks in the Doda district of Jammu and Kashmir State, NW Himalaya are exposed at eight places. They are named as Dramman, Piparan, Kaplas, Khol Dedni, Chinta, Bhala, Kai Nala, and Nagin Dhar Granites. They occur in the form of irregular bodies of varying dimensions. These granites are mostly leucocratic, two-mica, porphyritic to aplitic, massive and highly jointed with crude foliation in some cases. The contact with the Older Metamorphics is sharp and thermal aureole is absent. These granites are monzo- to syeno-granitic in composition with peraluminous, S-type (equivalent to ilmenite series) and calc-alkaline affinity. These intrusive bodies are emplaced within the Older Metamorphics under tectonic influences at later stages of metamorphism. They have formed from highly evolved anatectic granites derived by partial melting of lower crustal material with diapiric situations. These processes had been operative at a temperature of 600-700°C at a depth of 20-30 km under 5 Kb Pressure. The emplacement of these granites is suggested to be due to transient dilation where the diapir is enhanced by sheeting mechanism.

scholarly journals Extensional Carboniferous magmatism at the western margin of Gondwana: Las Lozas valley, Catamarca, Argentina

2016 ◽  
Vol 43 (1) ◽  
pp. 105 ◽  
Author(s):  
Beatriz Coira ◽  
Clara E. Cisterna ◽  
Horstpeter H. Ulbrich ◽  
Umberto G. Cordani
Keyword(s):  
Mantle Source ◽  
Granitic Rocks ◽  
Magma Source ◽  
Crustal Material ◽  
Nd Isotopes ◽  
Sierras Pampeanas ◽  
Juvenile Material ◽  
Lithospheric Extension ◽  
Eastern Sierras Pampeanas ◽  
Volcanic Succession

The Las Lozas volcanic sequence, which crops out at northwestern border of the Famatina belt-southeastern Puna, NW Argentina, is constituted mainly by rhyolites and a lesser volume of basalts and trachytes, and volcanoclastic deposits. These rocks, previously considered of Early Paleozoic age, are now assigned to the Lower Pennsylvanian (320 Ma U-Pb age). They represent a bimodal volcanic succession that plot in the subalkaline/tholeiitic (rhyolites), alkaline basalts (basalts) and alkaline (trachytes) fields on the total alkali-silica diagram. The basalts display features comparable to transitional MORB and within-plate tholeiites, with contributions from a mantle source affected by crustal contamination. The acid members also show geochemical affinities to within-plate magmas, and their composition suggest a derivation from continental crustal material with mantle source interaction or a juvenile essentially mantle derived crust. The 320 Ma age from the Las Lozas volcanic succession as well as the 342 and 348 Ma U-Pb ages, from rocks in the nearby Cazadero Grande section, to the south, and the U-Pb ages from Sierra Pampeanas granites (332-357 Ma) highlight the importance achieved by Carboniferous magmatic activity in that region, framed between 320 and 350 Ma. Low strontium initial ratios from the Las Lozas (0.70479-0.70164) indicate a predominant contribution by a juvenile component, while the ratios in the nearby Cazadero Grande (0.71433-0.71233) and Sierras Pampeanas granites (0.717 to 0.7124) point to an input by enriched sources with restricted contribution of a mantle component. Nd isotopes from a basalt from the Las Lozas section (εNd(320) with +3.11, TDM with 774.6 Ma) indicates a possible asthenospheric source, with evidence for some mixture between juvenile and reworked crustal material. In contrast Sr-Nd isotopes in a rhyolite from Cazadero Grande (εNd(t) of -2.91 and -0.3, TDM of 1.09 and 1.1 Ga) and of Sierra Pampeanas granites (εNd(t) of -0.6, TDM of 1.19 and 1.1 Ga) suggest a crustal source with minor juvenile input. Taking in account the age difference in the region between Mississippian and the Lower Pennsylvanian magmatism, this would indicate a change in the magma source consistent with a more pronounced extensional tectonic regime for the Lower Pennsylvanian. This assumption need to be considered together with observations along a transect at 27º30’S, where the Carboniferous Eastern Sierras Pampeanas granitic rocks show, regardless of age, a greater contribution of juvenile material of mantle character to the west. Among these rocks, with a major juvenile component, are those of the Las Lozas succession as well the Cerro Gloria Granite, the eastern manifestations of the Carboniferous Eastern Sierras Pampeanas magmatism. From the foregoing emerges that the contribution of juvenile material could be continuously varied in the region through the Carboniferous, due to varying lithospheric extension. An example of this arise from the presented data of the Lozas succession, which indicate that this rocks resulted from reworking of supra-crustal material with input of juvenile magmas, linked to the change in the lithospheric extension

Alteration and breakdown of xenotime-(Y) and monazite-(Ce) in granitic rocks of the Western Carpathians, Slovakia

Lithos ◽  
2005 ◽  
Vol 82 (1-2) ◽  
pp. 71-83 ◽  
Author(s):  
Igor Broska ◽  
C. Terry Williams ◽  
Marian Janák ◽  
Géza Nagy
Keyword(s):  
Granitic Rocks ◽  
Western Carpathians

Geochemistry and Sr–Nd isotopic composition of Eocene lamphrophyre dykes, southeastern British Columbia

2003 ◽  
Vol 40 (6) ◽  
pp. 853-864 ◽  
Author(s):  
J H Sevigny ◽  
R J Thériault
Keyword(s):  
British Columbia ◽  
Limited Range ◽  
Calc Alkaline ◽  
Lithospheric Thinning ◽  
Enriched Mantle ◽  
Mantle Enrichment ◽  
Mantle Reservoir ◽  
Geochemical Analyses ◽  
Alkaline Lamprophyres

Mineral compositions, geochemical analyses, and Sr–Nd isotopic compositions are reported for alkaline and calc-alkaline lamprophyres collected along the southern margin of the Valhalla Complex, southeastern British Columbia. The lamprophyres were emplaced during Eocene extension and lithospheric thinning associated with tectonic denudation of the Valhalla Complex. SiO2 contents range from 44.4–51.6 wt.%, K2O from 1.3–3.7 wt.%, and volatile contents (H2O + CO2 + SO3) from 0.8–4.6 wt.%. MgO and Cr contents are 9.5–7.6 wt.% and 540–130 ppm, respectively, for samples with Mg#s between 0.69 and 0.65. Chrondrite-normalized rare-earth element patterns are strongly fractionated with Cen = 120–375 and Ybn = 8.4–12.7. Alkaline lamprophyres contain biotite ± kaersutite ± calcic plagioclase and exhibit a limited range in initial 87Sr/86Sr (0.7051–0.7057), initial εNd (–3.7 to –4.3), and TDM (766–796 Ma). Calc-alkaline lamprophyres contain F-rich phlogopite and sodic plagioclase, and exhibit a wider range in initial 87Sr/86Sr (0.7064–0.7090), initial εNd (–6.3 to –11.9), and TDM (917–1,614 Ma). Alkaline lamprophyres are interpreted as uncontaminated melts derived from a long-term, volatile, and incompatible element-enriched mantle reservoir. Mantle enrichment coincided with continental rifting of western North America (ca. 760 Ma). The enriched mantle reservoir remained isolated for ~700 Ma. Lamprophyres were generated by partial melting of the mantle reservoir in response to adiabatic decompression and lithospheric thinning during Eocene extension.

scholarly journals Discrimination of Genealogical Groups of Arabica Coffee by the Chemical Composition of the Beans

2019 ◽  
Vol 11 (16) ◽  
pp. 141
Author(s):  
Larissa O. Fassio ◽  
Marcelo R. Malta ◽  
Gladyston R. Carvalho ◽  
Antônio A. Pereira ◽  
Ackson D. Silva ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Chemical Composition ◽  
Chemical Markers ◽  
Total Lipids ◽  
Germplasm Bank ◽  
Total Sugars ◽  
Coffee Beans ◽  
Different Levels ◽  
Important Marker

This work aimed to characterize and discriminate genealogical groups of coffee as to the chemical composition of the grains through the model created by PLS-DA method. 22 accessions of Coffea arabica, from the Active Germplasm Bank of Minas Gerais, were divided into groups according to the genealogical origin. Samples of ripe fruits were harvested selectively and processed by the wet method, to obtain pulped coffee beans, with 11% (b.u.) of water content. The raw beans were assessed as to the content of polyphenols, total sugars, total lipids, protein, caffeine, sucrose, and fatty acids. The data were submitted the chemometric analysis, PCA and PLS-DA. The results of PLS-DA identified the variables which most influence the classification of genealogical groups and possible chemical markers to accessions processed by the pulped method. The sucrose content was an important marker for the Exotic accession group. However, the content of polyphenols has been identified as a marker for the group Tymor Hybrid, and the caffeine for the bourbon group. The different fatty acids have been identified as markers for all genealogical groups, at different levels. The model PLS-DA is effective in discriminating genealogical groups from the chemical composition of the beans.

Lower Palaeozoic and Precambrian igneous rocks from eastern England, and their bearing on late Ordovician closure of the Tornquist Sea: constraints from U-Pb and Nd isotopes

1993 ◽  
Vol 130 (6) ◽  
pp. 835-846 ◽  
Author(s):  
S. R. Noble ◽  
R. D. Tucker ◽  
T. C. Pharaoh
Keyword(s):  
Volcanic Rocks ◽  
Igneous Rocks ◽  
Calc Alkaline ◽  
Nd Isotopes ◽  
Nd Isotope ◽  
Magmatic Arc ◽  
The North ◽  
Basement Rocks ◽  
Continental Arc ◽  
Lower Palaeozoic

AbstractThe U-Pb isotope ages and Nd isotope characteristics of asuite of igneous rocks from the basement of eastern England show that Ordovician calc-alkaline igneous rocks are tectonically interleaved with late Precambrian volcanic rocks distinct from Precambrian rocks exposed in southern Britain. New U-Pb ages for the North Creake tuff (zircon, 449±13 Ma), Moorby Microgranite (zircon, 457 ± 20 Ma), and the Nuneaton lamprophyre (zircon and baddeleyite, 442 ± 3 Ma) confirm the presence ofan Ordovician magmatic arc. Tectonically interleaved Precambrian volcanic rocks within this arc are verified by new U-Pb zircon ages for tuffs at Glinton (612 ± 21 Ma) and Orton (616 ± 6 Ma). Initial εNd values for these basement rocks range from +4 to - 6, consistent with generation of both c. 615 Ma and c. 450 Ma groups of rocksin continental arc settings. The U-Pb and Sm-Nd isotope data support arguments for an Ordovician fold/thrust belt extending from England to Belgium, and that the Ordovician calc-alkaline rocks formed in response to subductionof Tornquist Sea oceanic crust beneath Avalonia.

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