Generation of calc-alkaline andesite magma through crustal melting induced by emplacement of mantle-derived water-rich primary magma: Evidence from Rishiri Volcano, southern Kuril Arc

Lithos ◽  
2020 ◽  
Vol 354-355 ◽  
pp. 105362 ◽  
Author(s):  
Hajime Taniuchi ◽  
Takeshi Kuritani ◽  
Mitsuhiro Nakagawa
Keyword(s):  
Primary Magma ◽  
Crustal Melting ◽  
Calc Alkaline

Petrology and geochronology of the high-K calc-alkaline Mésanger magmatism (Armorican massif, France): a ca. 320 Ma old volcano-plutonic association

2011 ◽  
Vol 182 (6) ◽  
pp. 467-477 ◽  
Author(s):  
Céline Ducassou ◽  
Marc Poujol ◽  
Erwan Hallot ◽  
Olivier Bruguier ◽  
Michel Ballevre
Keyword(s):  
Variscan Orogeny ◽  
Crustal Melting ◽  
Calc Alkaline ◽  
Zircon Age ◽  
High K ◽  
Granitic Intrusions ◽  
Armorican Massif ◽  
First Time ◽  
Late Stages ◽  
Magmatic Event

Abstract The late stages of the Variscan orogeny in western and central Europe are characterized by the emplacement of numerous Carboniferous granitic intrusions. In the southern part of the Armorican massif, volcanic and plutonic rocks occur within the Carboniferous series of the Ancenis basin. Chemical analyses indicate that they belong to the same magmatic high-K calc-alkaline association of peraluminous composition, which likely derives from crustal melting of an igneous source. A LA-ICPMS U-Pb/zircon age of 319.3 ± 3.1 Ma dates, for the first time, this magmatic event and, by there, constrains the maximum age of both the end of the sedimentation and the northward tilting of the sediments in the Ancenis basin. This magmatic event is coeval with the sedimentation of the coal-bearing Namurian basins located along the Nort-sur-Erdre fault. These intrusions are interpreted as the feeding conduits of the volcano-sedimentary layers encountered in these basins. This would imply a minimal dextral displacement of ca. 20–25 km along the Nort-sur-Erdre fault.

scholarly journals Petrogenesis and tectonic evolution of metaluminous sub-alkaline granitoids from the Takab Complex, NW Iran

2010 ◽  
Vol 148 (2) ◽  
pp. 250-268 ◽  
Author(s):  
ROBAB HAJIALIOGHLI ◽  
MOHSSEN MOAZZEN ◽  
AHMAD JAHANGIRI ◽  
ROLAND OBERHÄNSLI ◽  
BEATE MOCEK ◽  
...  
Keyword(s):  
Tectonic Evolution ◽  
Mineral Chemistry ◽  
Quartz Diorite ◽  
Igneous Rocks ◽  
Metamorphic Rocks ◽  
Crustal Melting ◽  
Calc Alkaline ◽  
Nw Iran ◽  
Magmatic Rocks ◽  
Crustal Origin

AbstractThe Takab complex is composed of a variety of metamorphic rocks including amphibolites, metapelites, mafic granulites, migmatites and meta-ultramafics, which are intruded by the granitoid. The granitoid magmatic activity occurred in relation to the subduction of the Neo-Tethys oceanic crust beneath the Iranian crust during Tertiary times. The granitoids are mainly granodiorite, quartz monzodiorite, monzonite and quartz diorite. Chemically, the magmatic rocks are characterized by ASI<1.04, AI<0.87 and high contents of CaO (up to ~14.5 wt%), which are consistent with the I-type magmatic series. Low FeOt/(FeOt+MgO) values (<0.75) as well as low Nb, Y and K2O contents of the investigated rocks resemble the calc-alkaline series. Low SiO2, K2O/Na2O and Al2O3 accompanied by high CaO and FeO contents indicate melting of metabasites as an appropriate source for the intrusions. Negative Ti and Nb anomalies verify a metaluminous crustal origin for the protoliths of the investigated igneous rocks. These are comparable with compositions of the associated mafic migmatites, in the Takab metamorphic complex, which originated from the partial melting of amphibolites. Therefore, crustal melting and a collision-related origin for the Takab calc-alkaline intrusions are proposed here on the basis of mineralogy and geochemical characteristics. The P–T evolution during magmatic crystallization and subsolidus cooling stages is determined by the study of mineral chemistry of the granodiorite and the quartz diorite. Magmatic crystallization pressure and temperature for the quartz-diorite and the granodiorite are estimated to be P~7.8±2.5 kbar, T~760±75°C and P~5±1 kbar, T~700°C, respectively. Subsolidus conditions are consistent with temperatures of ~620°C and ~600°C, and pressures of ~5 kbar and ~3.5 kbar for the quartz-diorite and the granodiorite, respectively.

Late Archean tectono-magmatic evolution of the central Slave Province, Northwest Territories

1992 ◽  
Vol 29 (10) ◽  
pp. 2156-2170 ◽  
Author(s):  
J. E. King ◽  
W. J. Davis ◽  
C. Relf
Keyword(s):  
Northwest Territories ◽  
Lake Area ◽  
Crustal Melting ◽  
Magmatic Evolution ◽  
Calc Alkaline ◽  
Thermal Peak ◽  
Suprasubduction Zone ◽  
Slave Province ◽  
Peraluminous Granites ◽  
Intense Deformation

An early tectono-stratigraphic and late plutonic assemblage are distinguished in the central part of the Archean Slave Province (Contwoyto Lake area) on the basis of their relationship to deformation and metamorphic episodes, and by geochemical characteristics. The older assemblage, which predates the onset of intense deformation and the thermal peak of metamorphism, comprises 2.68–2.65 Ga calc-alkaline volcanic and plutonic rocks, as well as extensive turbidites. The younger assemblage comprises ca. 2.61–2.58 Ga plutonic units that were emplaced during and after deformation (D,–D3) and the thermal peak of metamorphism. Compositions of the late plutonic units vary systematically with time of intrusion from an early, calc-alkaline, diorite – tonalite suite to late peraluminous granites. The early assemblage is interpreted to represent remnants of an island arc (or arcs) overlain by turbidites and accreted during D1 and D2. The later assemblage is interpreted as a product of late- to post-accretion, suprasubduction-zone magmatism and associated crustal melting.

Laramide to Miocene syn-extensional plutonism in the Puerta del Sol area, central Sonora, Mexico

2017 ◽  
Vol 34 (1) ◽  
pp. 45 ◽  
Author(s):  
Elizard González-Becuar ◽  
Efrén Pérez-Segura ◽  
Ricardo Vega-Granillo ◽  
Luigi Solari ◽  
Carlos Manuel González-León ◽  
...  
Keyword(s):  
Metamorphic Core Complex ◽  
Primitive Mantle ◽  
Isotopic Ratios ◽  
Magmatic Evolution ◽  
Calc Alkaline ◽  
Core Complex ◽  
High K ◽  
Sierra Madre ◽  
Plutonic Rocks ◽  
Metamorphic Core

Plutonic rocks of the Puerta del Sol area, in central Sonora, represent the extension to the south of the El Jaralito batholith, and are part of the footwall of the Sierra Mazatán metamorphic core complex, whose low-angle detachment fault bounds the outcrops of plutonic rocks to the west. Plutons in the area record the magmatic evolution of the Laramide arc and the Oligo-Miocene syn-extensional plutonism in Sonora. The basement of the area is composed by the ca. 1.68 Ga El Palofierral orthogneiss that is part of the Caborca block. The Laramide plutons include the El Gato diorite (71.29 ± 0.45 Ma, U-Pb), the El Pajarito granite (67.9 ± 0.43 Ma, U-Pb), and the Puerta del Sol granodiorite (49.1 ± 0.46 Ma, U-Pb). The younger El Oquimonis granite (41.78 ± 0.32 Ma, U-Pb) is considered part of the scarce magmatism that in Sonora records a transition to the Sierra Madre Occidental magmatic event. The syn-extensional plutons are the El Garambullo gabbro (19.83 ± 0.18 Ma, U-Pb) and the Las Mayitas granodiorite (19.2 ± 1.2 Ma, K-Ar). A migmatitic event that affected the El Palofierral orthogneiss, El Gato diorite, and El Pajarito granite between ca. 68 and 59 Ma might be related to the emplacement of the El Pajarito granite. The plutons are metaluminous to slightly peraluminous, with the exception of El Oquimonis granite, which is a peraluminous two-mica, garnet-bearing granite. They are mostly high-K calc-alkaline with nearly uniform chondrite-normalized REE and primitive-mantle normalized multielemental patterns that are characteristic of continental margin arcs and resemble patterns reported for other Laramide granites of Sonora. The Laramide and syn-extensional plutons also have Sr, Nd and Pb isotopic ratios that plot within the fields reported for Laramide granites emplaced in the Caborca terrane in northwestern and central Sonora. Nevertheless, and despite their geochemical affinity to continental magmatic arcs, the El Garambullo gabbro and Las Mayitas granodiorite are syn-extensional plutons that were emplaced at ca. 20 Ma during development of the Sierra Mazatán metamorphic core complex. The 40Ar/39Ar and K-Ar ages obtained for the El Palofierral orthogneiss, the Puerta del Sol granodiorite, the El Oquimonis granite, and the El Garambullo gabbro range from 26.3 ± 0.6 to 17.4 ± 1.0 Ma and are considered cooling ages associated with the exhumation of the metamorphic core complex.

Two episodes of monazite crystallization during metamorphism and crustal melting in the Everest region of the Nepalese Himalaya

Geology ◽  
2000 ◽  
Vol 28 (5) ◽  
pp. 403-406 ◽  
Author(s):  
Robert L. Simpson ◽  
Randall R. Parrish ◽  
Mike P. Searle ◽  
David J. Waters
Keyword(s):  
Crustal Melting

scholarly journals Magma Mixing Genesis of the Mafic Enclaves in the Qingshanbao Complex of Longshou Mountain, China: Evidence from Petrology, Geochemistry, and Zircon Chronology

Minerals ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 195 ◽  
Author(s):  
Wenheng Liu ◽  
Xiaodong Liu ◽  
Jiayong Pan ◽  
Kaixing Wang ◽  
Gang Wang ◽  
...  
Keyword(s):  
Host Rock ◽  
Inductively Coupled Plasma ◽  
Magma Mixing ◽  
Coarse Grained ◽  
Calc Alkaline ◽  
Quartz Crystals ◽  
Alkaline Rocks ◽  
Mafic Enclaves ◽  
Normal Zoning ◽  
Host Rocks

The Qingshanbao complex, part of the uranium metallogenic belt of the Longshou-Qilian mountains, is located in the center of the Longshou Mountain next to the Jiling complex that hosts a number of U deposits. However, little research has been conducted in this area. In order to investigate the origin and formation of mafic enclaves observed in the Qingshanbao body and the implications for magmatic-tectonic dynamics, we systematically studied the mineralogy, petrography, and geochemistry of these enclaves. Our results showed that the enclaves contain plagioclase enwrapped by early dark minerals. These enclaves also showed round quartz crystals and acicular apatite in association with the plagioclase. Electron probe analyses showed that the plagioclase in the host rocks (such as K-feldspar granite, adamellite, granodiorite, etc.) show normal zoning, while the plagioclase in the mafic enclaves has a discontinuous rim composition and shows instances of reverse zoning. Major elemental geochemistry revealed that the mafic enclaves belong to the calc-alkaline rocks that are rich in titanium, iron, aluminum, and depleted in silica, while the host rocks are calc-alkaline to alkaline rocks with enrichment in silica. On Harker diagrams, SiO2 contents are negatively correlated with all major oxides but K2O. Both the mafic enclaves and host rock are rich in large ion lithophile elements such as Rb and K, as well as elements such as La, Nd, and Sm, and relatively poor in high field strength elements such as Nb, Ta, P, Ti, and U. Element ratios of Nb/La, Rb/Sr, and Nb/Ta indicate that the mafic enclaves were formed by the mixing of mafic and felsic magma. In terms of rare earth elements, both the mafic enclaves and the host rock show right-inclined trends with similar weak to medium degrees of negative Eu anomaly and with no obvious Ce anomaly. Zircon LA-ICP-MS (Laser ablation inductively coupled plasma mass spectrometry) U-Pb concordant ages of the mafic enclaves and host rock were determined to be 431.8 5.2 Ma (MSWD (mean standard weighted deviation)= 1.5, n = 14) and 432.8 4.2 Ma (MSWD = 1.7, n = 16), respectively, consistent with that for the zircon U-Pb ages of the granite and medium-coarse grained K-feldspar granites of the Qingshanbao complex. The estimated ages coincide with the timing of the late Caledonian collision of the Alashan Block. This comprehensive analysis allowed us to conclude that the mafic enclaves in the Qingshanbao complex were formed by the mixing of crust-mantle magma with mantle-derived magma due to underplating, which caused partial melting of the ancient basement crust during the collisional orogenesis between the Alashan Block and Qilian rock mass in the early Silurian Period.

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