Geochemical and geochronological evidence for Early Triassic calc-alkaline magmatism in the Menderes Massif, western Turkey

2001 ◽  
Vol 89 (4) ◽  
pp. 822-835 ◽  
Author(s):  
O. E. Koralay ◽  
M. Satir ◽  
O. Ö. Dora
Keyword(s):  
Alkaline Magmatism ◽  
Early Triassic ◽  
Calc Alkaline ◽  
Western Turkey ◽  
Menderes Massif ◽  
Geochronological Evidence

Volcanisme triasique calco-alcalin a shoshonitique du Nevada occidental

2001 ◽  
Vol 172 (2) ◽  
pp. 189-200 ◽  
Author(s):  
Olivier Blein ◽  
Henriette Lapierre ◽  
Richard A. Schweickert ◽  
Arnaud Pecher ◽  
Cedric Reynaud
Keyword(s):  
Sierra Nevada ◽  
Middle Triassic ◽  
Island Arc ◽  
Primitive Mantle ◽  
Alkaline Magmatism ◽  
Early Triassic ◽  
Late Permian ◽  
Calc Alkaline ◽  
High K ◽  
T Values

Abstract Two types of island-arc occur in the North American Cordillera during the Permian-Triassic times. The first type is exposed in the eastern Klamath and Blue Mountains (fig. 1). Its stratigraphy is continuous from Permian to Triassic, and is composed of arc-tholeiites with minor calc-alkaline lavas. This suite shows high epsilon Nd (sub (T)) values similar to the range of intra-oceanic island-arc [Lapierre et al., 1987; Brouxel et al., 1987, 1988; Charvet et al., 1990; Lapierre et al., 1990, 1994]. In contrast, the second type, exposed in northern Sierra Nevada and central-western Nevada (Black Dyke) (fig. 1), is characterized by an early Permian calc-alkaline suite, with positive to negative epsilon Nd (sub (T)) values. Its basement is inferred to present continental affinities [Rouer et Lapierre, 1989; Rouer et al., 1989; Blein et al., 1996, 2000]. In western Nevada, volcanic rocks of early Triassic age are present in few localities: (1) the Triassic Koipato Group in central Nevada (fig. 1); (2) the Pablo Formation in the Shoshone mountains and the Paradise Range (figs. 1 and 2); and (3) the Garfield Flat formation in the Excelsior mountains (figs. 1 and 2). Silberling [1959] has subdivided the Pablo formation into three members: clastic, limestone, and greenstone (fig. 3). The clastic member consists of andesites, interbedded with volcaniclastic turbidites. The contact between the clastic and the limestone members is gradational and interlensing. The limestones are locally bioclastic with shell fragments, indicating a shallow-water deposition. They yielded a reworked late Permian fauna which suggests a late Permian or younger age. The clastic and limestone members could represent the recurrent rapid deposition in a shallow marine basin of volcanic flows, reworked material from a nearby terrane of volcanic, granitic, and sedimentary rocks. The greenstone member is composed of andesites, volcanic breccias and tuffs. The middle Triassic Granstville formation rests conformably on the Pablo formation. Both formations are affected by Mesozoic polyphase deformations [Oldow, 1985]. The Permian and/or Triassic Garfield Flat formation is composed of ignimbrites and pyroclastic breccia interlayered with conglomerates, sandstones, calcareous and red pelites (fig. 4). The Jurassic-Triassic Gabbs-Sunrise formation rests unconformably on the Garfield Flat formation. Both formations are affected by Mesozoic polyphase deformations [Oldow, 1985]. In the Pablo formation, lavas are shoshonitic basalts and calc-alkaline andesites, while calc-alkaline andesites and rhyolites predominate in the Garfield Flat formation. Basalts and andesites exhibit enriched LREE patterns (fig. 6) with slight negative anomalies in TiO 2 , Nb and Ta typical of subducted-related magmas in the primitive mantle-normalized spidergrams (fig. 7). The lavas show epsilon Sr (sub (T)) and epsilon Nd (sub (T)) values which range between -0.4 to +19.6, and -1.4 to +0.8 respectively (fig. 8). Most of the samples are displaced from the mantle array toward higher epsilon Sr (sub (T)) values, due to the alteration. The epsilon Nd (sub (T)) values, close to the Bulk Earth composition, record an interaction between material from a juvenile pole (mantle or young crust) and from an old crust. The Pablo and Garfield Flat formations differ from the Permian Black Dyke formation. This latter is characterized by calc-alkaline basalts and mafic andesites enriched in LREE, and a mantle source contaminated by subducted sediments or arc-basement [Blein et al., 2000]. The Pablo and Garfield Flat formations show many similarities with the Koipato Group. In central Nevada, the Koipato Group is a sequence of andesites, dacites and rhyolites interbedded with tuffs and volcaniclastic sediments. It rests with a marked angular unconformity on folded Upper Paleozoic oceanic rocks [Silberling and Roberts, 1962]. Fission-track dating on zircon [McKee and Burke, 1972] indicate an age of 225+ or -30 Ma for the Koipato Group. Ammonites, near the top, are considered to be upper early Triassic [Silberling, 1973]. The Pablo and Garfield Flat lavas share in common with the Koipato Group: (1) late Permian to middle Triassic ages; (2) abundant andesites and rhyolites with minor basalts, associated with felsic pyroclastic breccias; (3) LILE and LREE enrichement; (4) low epsilon Nd (sub (T)) values suggesting a juvenile source with slight contamination by a crustal component; (5) La/Nb ratios close to the lower limit of orogenic andesites [Gill, 1981]; and (6) high Nb/Zr ratios suggesting a generation far from a subduction zone [Thieblemont and Tegyey, 1994]. This Triassic high-K calc-alkaline to shoshonitic magmatism is enriched in K, Rb, Th, Nb and Ta relative to the calc-alkaline Black Dyke lavas, and is mainly juvenile judging from Nd isotopic ratios. The source may correspond either to a juvenile crust composed of high-K andesites [Roberts and Clemens, 1993], which could be the Black Dyke lavas, or to phlogopite-K-richterite enriched lithospheric mantle. In both cases, the generation of the high-K calc-alkaline magmatism needs the former existence of an important subduction phase to generate its source. The lavas of the Pablo and Garfield Flat formations are similar to calc-alkaline and shoshonitic lavas emitted in post-collisional setting. Post-collisional arc/continent magmatism is varied from intermediate to felsic, calc-alkaline to shoshonitic, low to high-K and meta-aluminous to hyper-aluminous. The studied lavas may be compared to the arc/passive margin collision of Papua-New Guinea, where a post-collisional magmatism characterized by high-K basalts, andesites and shoshonites [McKenzie, 1976]. In Nevada, this post-collisional event develops after the accretion of the Permian Black Dyke island-arc (Type 2), and before the accretion of the intra-oceanic Permo-Triassic arc (Type 1).

scholarly journals 207Pb-206Pb dating of magnetite, monazite and allanite in the central and northern Nagssugtoqidian orogen, West Greenland

2006 ◽  
Vol 11 ◽  
pp. 101-114 ◽  
Author(s):  
Henrik Stendal ◽  
Karsten Secher ◽  
Robert Frei
Keyword(s):  
Hydrothermal Activity ◽  
Alkaline Magmatism ◽  
Calc Alkaline ◽  
Isotopic Data ◽  
Sulphide Deposit ◽  
Late Archaean ◽  
West Greenland ◽  
Isotopic Signatures ◽  
Source Characteristics ◽  
Isotopic Measurements

Pb-isotopic data for magnetite from amphibolites in the Nagssugtoqidian orogen, central West Greenland, have been used to trace their source characteristics and the timing of metamorphism. Analyses of the magnetite define a Pb-Pb isochron age of 1726 ± 7 Ma. The magnetite is metamorphic in origin, and the 1726 Ma age is interpreted as a cooling age through the closing temperature of magnetite at ~600°C. Some of the amphibolites in this study come from the Naternaq supracrustal rocks in the northern Nagssugtoqidian orogen, which host the Naternaq sulphide deposit and may be part of the Nordre Strømfjord supracrustal suite, which was deposited at around 1950 Ma ago. Pb-isotopic signatures of magnetite from the Arfersiorfik quartz diorite in the central Nagssugtoqidian orogen are compatible with published whole-rock Pb-isotopic data from this suite; previous work has shown that it is a product of subduction-related calc-alkaline magmatism between 1920 and 1870 Ma. Intrusion of pegmatites occurred at around 1800 Ma in both the central and the northern parts of the orogen. Pegmatite ages have been determined by Pb stepwise leaching analyses of allanite and monazite, and source characteristics of Pb point to an origin of the pegmatites by melting of the surrounding late Archaean and Palaeoproterozoic country rocks. Hydrothermal activity took place after pegmatite emplacement and continued below the closure temperature of magnetite at 1800– 1650 Ma. Because of the relatively inert and refractory nature of magnetite, Pb-isotopic measurements from this mineral may be of help to understand the metamorphic evolution of geologically complex terrains.

The relationship between potassic, calc-alkaline and Na-alkaline magmatism in South Italy volcanoes: A melt inclusion approach

2004 ◽  
Vol 220 (1-2) ◽  
pp. 121-137 ◽  
Author(s):  
Pierre Schiano ◽  
Robert Clocchiatti ◽  
Luisa Ottolini ◽  
Alessandro Sbrana
Keyword(s):  
Melt Inclusion ◽  
Alkaline Magmatism ◽  
Calc Alkaline ◽  
South Italy ◽  
The Relationship

Fluids composition in the mantle beneath the Eastern Transylvanian Basin inferred from mineral chemistry and noble gases in fluid inclusions of ultramafic xenoliths

2021 ◽  
Author(s):  
Andrea Luca Rizzo ◽  
Barbara Faccini ◽  
Costanza Bonadiman ◽  
Theodoros Ntaflos ◽  
Ioan Seghedi ◽  
...  
Keyword(s):  
Fluid Inclusions ◽  
Noble Gases ◽  
Mineral Chemistry ◽  
Mantle Xenoliths ◽  
Alkaline Magmatism ◽  
Volcanic Area ◽  
Crustal Material ◽  
Calc Alkaline ◽  
Depleted Mantle ◽  
Magmatic Gases

<p>The investigation of noble gases (He, Ne, Ar) and CO<sub>2</sub> in fluid inclusions (FI) of mantle-derived rocks from the Sub Continental Lithospheric Mantle (SCLM) is crucial for constraining its geochemical features and evolution as well as the volatiles cycle, and for better evaluating the information arising from the study and monitoring of volcanic and geothermal gases. Eastern Transylvanian Basin in Romania is one of the places in Central-Eastern Europe where mantle xenoliths are brought to the surface by alkaline magmatism, offering the opportunity for applying the above-mentioned approach. Moreover, this locality is one of the few places on Earth where alkaline eruptions occurred contemporaneously with calc-alkaline activity, thus being a promising area for the investigation of subduction influence on the magma sources and volatiles composition.</p><p>In this work, we studied petrography, mineral chemistry and noble gases in FI of mantle xenoliths found in Perşani Mts. alkaline volcanic products. Our findings reveal that the local mantle recorded two main events. The first was a pervasive, complete re-fertilization of a previously depleted mantle by a calc-alkaline subduction-related melt, causing the formation of very fertile, amphibole-bearing lithotypes. Fluids involved in this process and trapped in olivine, opx and cpx, show <sup>4</sup>He/<sup>40</sup>Ar* ratios up to 1.2 and among the most radiogenic <sup>3</sup>He/<sup>4</sup>He values of the European mantle (5.8 ± 0.2 Ra), reflecting the recycling of crustal material in the local lithosphere. The second event is related to a later interaction with an alkaline metasomatic agent similar to the host basalts, that caused slight LREE enrichment in pyroxenes and crystallization of disseminated amphiboles, with FI showing <sup>4</sup>He/<sup>40</sup>Ar* and <sup>3</sup>He/<sup>4</sup>He values up to 2.5 and 6.6 Ra, respectively, more typical of magmatic fluids.</p><p>Although volcanic activity in the Perşani Mts. is now extinct, strong CO<sub>2</sub> degassing (8.7 × 10<sup>3</sup> t/y) in the neighbouring Ciomadul volcanic area may indicate that magma is still present at depth (Kis et al., 2017; Laumonier et al., 2019). The gas manifestations present from Ciomadul area are the closest to the outcrops containing mantle xenoliths for comparison of the noble gas composition in FI. <sup>3</sup>He/<sup>4</sup>He values from Stinky Cave (Puturosul), Doboşeni and Balvanyos are up to 3.2, 4.4 and 4.5 Ra, respectively, indicating the presence of a cooling magma (Vaselli et al., 2002 and references therein). In the same area and more recently, Kis et al. (2019) measured <sup>3</sup>He/<sup>4</sup>He ratios up to 3.1 Ra, arguing that these values indicate a mantle lithosphere strongly contaminated by subduction-related fluids and post-metasomatic ingrowth of radiogenic <sup>4</sup>He. Our findings consider more likely that magmatic gases from Ciomadul volcano are not representative of the local mantle but are being released from a cooling and aging magma that resides within the crust. Alternatively, crustal fluids contaminate magmatic gases while they are rising to the surface.</p><p> </p><p>Kis et al. (2017). Journal of Volcanology and Geothermal Research 341, 119–130.</p><p>Kis et al. (2019) Geochem. Geophys. Geosyst. 20, 3019-3043.</p><p>Laumonier et al. (2019) Earth and Planetary Science Letters, 521, 79-90.</p><p>Vaselli et al. (2002) Chemical Geology 182, 637–654.</p>

scholarly journals A step towards unraveling the paleogeographic attribution of pre-Mesozoic basement complexes in the Western Alps based on U–Pb geochronology of Permian magmatism

2020 ◽  
Vol 113 (1) ◽  
Author(s):  
Michel Ballèvre ◽  
Audrey Camonin ◽  
Paola Manzotti ◽  
Marc Poujol
Keyword(s):  
Early Stage ◽  
Western Alps ◽  
Geochemical Data ◽  
Alkaline Magmatism ◽  
Low Grade ◽  
Calc Alkaline ◽  
Alpine Orogeny ◽  
History Of ◽  
External Part ◽  
The One

Abstract The Briançonnais Domain (Western Alps) represented the thinned continental margin facing the Piemonte-Liguria Ocean, later shortened during the Alpine orogeny. In the external part of the External Briançonnais Domain (Zone Houillère), the Palaeozoic basement displays microdioritic intrusions into Carboniferous sediments and andesitic volcanics resting on top of the Carboniferous sediments. These magmatic rocks are analysed at two well-known localities (Guil volcanics and Combarine sill). Geochemical data show that the two occurrences belong to the same calc-alkaline association. LA-ICP-MS U–Pb ages have been obtained for the Guil volcanics (zircon: 291.3 ± 2.0 Ma and apatite: 287.5 ± 2.6 Ma), and the Combarine sill (zircon: 295.9 ± 2.6 Ma and apatite: 288.0 ± 4.5 Ma). These ages show that the calc-alkaline magmatism is of Early Permian age. During Alpine orogeny, a low-grade metamorphism, best recorded by lawsonite-bearing veins in the Guil andesites, took place at about 0.4 GPa, 350 °C in the External Briançonnais and Alpine metamorphism was not able to reset the U–Pb system in apatite. The Late Palaeozoic history of the Zone Houillère is identical to the one recorded in the Pinerolo Unit, located further East in the Dora-Maira Massif, and having experienced a garnet-blueschist metamorphism during the Alpine orogeny. The comparison of these two units allows for a better understanding of the link between the Palaeozoic basements, mostly subducted during the Alpine convergence, and their Mesozoic covers, generally detached at an early stage of the convergence history.

Tertiary calc-alkaline magmatism associated with lithospheric extension in the Pacific Northwest

1995 ◽  
Vol 100 (B6) ◽  
pp. 10303-10319 ◽  
Author(s):  
P. R. Hooper ◽  
D. G. Bailey ◽  
G. A. McCarley Holder
Keyword(s):  
Pacific Northwest ◽  
Alkaline Magmatism ◽  
Calc Alkaline ◽  
The Pacific ◽  
Lithospheric Extension

Magnetite–apatite intrusions and calc-alkaline magmatism, Camsell River, N.W.T.

1976 ◽  
Vol 13 (2) ◽  
pp. 348-354 ◽  
Author(s):  
J. P. N. Badham ◽  
R. D. Morton
Keyword(s):  
Volcanic Rocks ◽  
Orogenic Belt ◽  
Alkaline Magmatism ◽  
Calc Alkaline ◽  
Immiscible Liquids ◽  
Intermediate Composition ◽  
Andean Type

The Camsell River area comprises a roof pendant of volcanic rocks within an Aphebian (~1800 m.y.) orogenic belt. Magnetite–apatite intrusions and related bodies are common and are closely associated with plutons of intermediate composition. The magnetitic intrusions are interpreted as immiscible liquids that separated from a magma of intermediate composition. The immiscible fractions were predominantly crystalline when they reached their present higher levels, and final emplacement was facilitated by volatile-streaming and fluidization. Their presence in the orogenic belt is taken as further support for the hypothesis that the orogen was of Andean type.

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