کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
4731354 | 1640406 | 2012 | 13 صفحه PDF | دانلود رایگان |
The Nagarparker area of the Trans-Aravalli Belt comprises Precambrian igneous and metamorphic basement rocks, predominantly granites. These granites are subalkalic to alkalic A-type containing riebeckite, ferro-richterite, ferro-edenite ± arvedsonite amphiboles, and rutile, zircon, apatite, allanite, titanite, titano-magnetite, ilmenite, magnetite and fluorite accessory minerals. The variations in Nb, Y, Ce and Ga and Ga/Al ratios typify the granites of the area as post-orogenic A2-type, formed possibly by partial melting of the island arc crust in a rift-related within plate tectonic setting. The granites of the area yielded U–Th–Pb EPMA zircon and monazite radiometric ages between 1100 and 700 Ma, mostly concentrating around ∼750 Ma. Based on petrological, geochemical and geochronological resemblance of granites of the Nagarparker area with those of the Seychelles islands and the Malani Igneous Suite, it is inferred that being part of Trans-Aravalli Belt of the Indian shield, the Nagarparker area might have shouldered the Seychelles islands towards the western side of the Rodinia before the supercontinent rifted in Neoproterozoic.
► Nagarparker area comprises Precambrian basement rocks (igneous and metamorphic).
► Granites are dominant which occur as stocks, bosses and sheet-like intrusions.
► They are A2-type granites formed in a rift-related within plate tectonic setting.
► Zircon and monazite U–Th–Pb ages are 1100–700 Ma and concentrate at 750 Ma.
► Nagarparker shouldered Seychelles on west of Rodinia which tore in Neoproterozoic.
Journal: Journal of Asian Earth Sciences - Volume 59, 1 October 2012, Pages 39–51