Gr. Dikshitulu et Rd. Raju, PETROLOGY AND GEOCHEMISTRY OF THE GRANITOIDS OF CENTRAL GNEISSIC COMPLEX IN THE KAMENG DISTRICT, ARUNACHAL-PRADESH, Journal of the Geological Society of India, 50(4), 1997, pp. 407-419
Petrology and geochemistry (major, minor and trace elements including
REE) of the different granitoids from Central Gnessic Complex indicate
that, (a) the dominant Palaeoproterozoic migmatite, hornblende granit
e gneiss, two-mica granite and augen gneiss are syn-kinematic, autocht
honous, peraluminous, low-Ca granodiorite, with the first three being
of S-type formed by high-degree (> 50%) anatexis of sediments of psamm
opelitic composition, whereas the augen gneiss is I-type formed by par
tial melting of a basic rock of mantle affinity coupled with notable c
rustal contamination and affected by soda metasomatism; (b) the minor
Mesoproterozoic Salari granite is late-kinematic, allochthonous, metaa
luminous, epidote-bearing, high-Ca monzogranite of I-type formed by pa
rtial melting of basic rock from crustal depth; (c) the youngest (ca.
30 Ma) tourmaline granite is post-kinematic, allochthonous, strongly p
eraluminous, high-level syenogranite of S-type, with its parental melt
derived from a peraluminous granitoid by anatexis induced by large vo
lume of volatiles and fluids, and (d) tectonically, these granitoids a
re of 'syn-collision' type.