Tectonic Fabric, Geochemistry, and Zircon-Monazite Geochronology as Proxies to Date an Orogeny: Example of South Delhi Orogeny, NW India, and Implications for East Gondwana Tectonics

We have dated the South Delhi orogeny, Aravalli-Delhi Mobile Belt (ADMB), NW India, using tectonic fabric, geochemistry, and zircon-monazite geochronology as proxies. The Terrane (SDT), a passive margin domain in ADMB, consists of multiply deformed (D 1 –D 4 ) greenschist facies rocks several granite plutons. D deformation is characterized by pervasive isoclinal recumbent F fold axial planar tectonometamorphic S , developed all rock types. minerals belong to peak metamorphism, M suggesting syntectonic nature with . age -M constrained syncollisional peralkaline type Sewariya which magmatic/submagmatic fabric (S m coplanar pluton turned into quartzofeldspathic gneiss carrying evidence high temperature deformation. estimated at ca. 878 Ma zircon geochronology. further monazite mica schist 865–846 Ma. other plutons metarhyolite are pre-D emplaced 992–946 2 produced NE-SW trending open upright folds coaxial northwesterly vergent –axial thrusts. Monazite constrains 811–680 3 small large scale NW-SE folds, faults fractures marking brittle rocks. 588–564 There upper amphibolitic slivers along -Phulad thrust, belonging pre-Delhi rocks, show 1,638 metamorphism age. From above study, it suggested that orogeny belongs 878–680 final amalgamation Marwar Craton rest India. This overlaps early phase Pan-African (900–630 Ma). deformation, coincides Kuunga (650–500 Our study implies like continents East Gondwana, underwent internal blocks until late part Neoproterozoic.