Geochemistry and petrogenesis of the Proterozoic dykes in Tamil nadu, southern India: another example of the Archaean lithospheric mantle source

1998 ◽  
Vol 87 (3) ◽  
pp. 268 ◽  
Author(s):  
T. Radhakrishna ◽  
M. Joseph
Keyword(s):  
Mantle Source ◽  
Lithospheric Mantle ◽  
Tamil Nadu ◽  
Southern India ◽  
Lithospheric Mantle Source

scholarly journals Deep Crustal Contamination of the Lithospheric Mantle Source to Variscan Ultrapotassic Magmas – Geochemical and Geodynamic Consequences

2020 ◽  
Author(s):  
Vojtěch Janoušek ◽  
John Milan Hora ◽  
Yulia Erban Kochergina ◽  
Simon Couzinié ◽  
Tomáš Magna ◽  
...  
Keyword(s):  
Mantle Source ◽  
Lithospheric Mantle ◽  
Crustal Contamination ◽  
Lithospheric Mantle Source

scholarly journals Petrology and origin of the Lar igneous complex of the Sistan suture zone, Iran

Geologos ◽  
2020 ◽  
Vol 26 (1) ◽  
pp. 51-64
Author(s):  
Mohammad Boomeri ◽  
Rahele Moradi ◽  
Sasan Bagheri
Keyword(s):  
Partial Melting ◽  
Mantle Source ◽  
Lithospheric Mantle ◽  
Crustal Contamination ◽  
Suture Zone ◽  
Fractional Crystallisation ◽  
Igneous Rocks ◽  
Positive Anomaly ◽  
Igneous Complex ◽  
Lithospheric Mantle Source

AbstractThe Oligocene Lar igneous complex is located in the Sistan suture zone of Iran, being emplaced in Paleocene to Eocene flysch-type rocks. This complex includes mainly intermediate K-rich volcanic (trachyte, latite and andesite) and plutonic (syenite and monzonite) rocks that belong to shoshonitic magma. The geochemical characteristics of the Lar igneous complex, such as an enrichment of LREE and LILE relative to HREE and HFSE, respectively, a negative anomaly of Ti, Ba and Nb and a positive anomaly of Rb and Th are similar to those of arc-type igneous rocks. Tectonic discrimination diagrams also show that rocks of the Lar igneous complex fall within the arc-related and post-collisional fields and K-enrichment of these rocks confirm the post-collisional setting. Based on geochemical features, the Lar igneous complex magma was derived from partial melting of a phlogopite-bearing, enriched and metasomatised lithospheric mantle source and the magma was affected by some evolutionary processes like fractional crystallisation and crustal contamination.

scholarly journals The enriched Variscan lithosphere of NE Iberia: data from postcollisional Permian calc-alkaline lamprophyre dykes of Les Guilleries

2021 ◽  
Vol 19 ◽  
pp. 1-23
Author(s):  
Esteban Mellado ◽  
Mercè Corbella ◽  
Didac Navarro ◽  
Andrew Kylander
Keyword(s):  
Mantle Source ◽  
Lithospheric Mantle ◽  
Subcontinental Lithospheric Mantle ◽  
Volatile Content ◽  
Calc Alkaline ◽  
Geochronological Data ◽  
Metamorphic Basement ◽  
Lithospheric Mantle Source ◽  
Porphyritic Texture ◽  
Alkaline Lamprophyres

Post-collisional mafic dykes crosscut the Paleozoic metamorphic basement and late-Variscan plutons in Les Guilleries massif (Catalan Coastal Ranges, NE Iberia). The predominance of mafic phenocrysts, porphyritic texture, abundant amphibole, high MgO and volatile content, together with crustal-like trace-element patterns indicate that the dykes correspond to calc-alkaline lamprophyres, mainly spessartites. Their enrichment in LILE, HFSE and REE and initial Sr-Nd isotopic compositions (87Sr/86Sri between 0.70851 and 0.71127, epsilon Ndi between -5.23 and -4.63) are consistent with an enriched subcontinental lithospheric mantle source. U-Pb ages of matrix titanite crystals yield concordia ages of 262±7Ma, congruent with crosscutting relationships. Postmagmatic processes are evidenced by intense chloritization and albitization of the lamprophyres, together with systematic variations of Na2O vs SiO2, K2O, CaO, Ba, Rb, Cs, Pb, Sr, Tl, and Zn, and possibly the removal of F. The geochemical and geochronological data support an orogenic geochemical affinity, in accordance with the transitional tectonic regime between Variscan compression/transpression and post-collisional transtension/extension, related to the fragmentation of Pangea and thinning of the lithosphere. The lamprophyre dykes studied could represent the youngest pulse of Variscan orogenic magmatism and, therefore, mark its end in NE Iberia before the onset of the generalized Triassic extension.

scholarly journals Geochemical and isotopical variations within the Campanian Comagmatic Province: implications on magma source composition

2021 ◽  
Vol 47 (4) ◽  
Author(s):  
Monica Piochi ◽  
Lucia Pappalardo ◽  
Gianfilippo De Astis
Keyword(s):  
Mantle Source ◽  
Lithospheric Mantle ◽  
Campi Flegrei ◽  
Magma Source ◽  
Isotopic Ratios ◽  
Italian Peninsula ◽  
Mantle Sources ◽  
Compositional Variations ◽  
Volcanic Islands ◽  
Lithospheric Mantle Source

A spatial variation in chemical and isotopical composition is observed between the volcanoes belonging to the Campanian Comagmatic Province. At a given MgO content, magmas from volcanic islands (Procida and Ischia) are enriched in Ti, Na, depleted in La, Ba, Rb, Sr, Th, K contents, and shows lower LREE/HFSE (e.g., La/Nb = = 1-2), lower Sr-Pb isotopic ratios and higher Nd isotopic ratios with respect to magmas from volcanoes locat- ed inland (Campi Flegrei and Somma-Vesuvius). The observed compositional variations are explained involving two different mantle sources in the genesis of the magmas erupted in this region: a deeper asthenospheric man- tle source, from which the Tyrrhenian magmas also derived and a lithospheric mantle source enriched by slab- derived fluids. The contribution of the enriched-lithospheric mantle became more pronounced moving from the Tyrrhenian abyssal plain through the Italian Peninsula where it dominates, likely in response to the thickening of the lithosphere observed under the Peninsula

Two-pyroxene syenitoids from the Moldanubian Zone of the Bohemian Massif: Peculiar magmas derived from a strongly enriched lithospheric mantle source

Lithos ◽  
2019 ◽  
Vol 342-343 ◽  
pp. 239-262 ◽  
Author(s):  
Vojtěch Janoušek ◽  
František V. Holub ◽  
Kryštof Verner ◽  
Renata Čopjaková ◽  
Axel Gerdes ◽  
...  
Keyword(s):  
Mantle Source ◽  
Bohemian Massif ◽  
Lithospheric Mantle ◽  
Moldanubian Zone ◽  
Lithospheric Mantle Source
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