Geochemical and geochronological data from charnockites and anorthosites from India's Kodaikanal-Palani Massif, Southern Granulite Terrain, India


Sayıt K. , Catlos E. J. , Sivasubramanian P., Dubey C. S.

Topics in Igneous Petrology: a tribute to Prof. Mihir K. Bose, Ray,J.,Sen,G.,and Ghosh,B., Editör, Springer, Berlin, ss.383-417, 2011

  • Basım Tarihi: 2011
  • Yayınevi: Springer
  • Basıldığı Şehir: Berlin
  • Sayfa Sayıları: ss.383-417
  • Editörler: Ray,J.,Sen,G.,and Ghosh,B., Editör

Özet

The Kodaikanal–Palani Massif is an important component of India’s

Southern Granulite Terrain; understanding the tectonic history of its rocks lends

considerable insight into its role within South India. The massif is located south

of the Palghat Cauvery Shear Zone (PCSZ). Compilations of available geochronologic

and geochemical information from charnockites north and south of the PCSZ

show these rocks largely differ in age, with northern samples recording Archaean

crystallization events, whereas those to the south yielding Cambro-Ordovician and

Neoproterozoic ages. The Kodaikanal–Palani charnockitic rocks contain monazite

grains that fall within the Cambro-Ordovician timescale. The Oddanchatram

anorthosite, located along the northern boundary of the Kodaikanal–Palani Massif,

contains zircon grains that record mid-Neoproterozoic to Cambro-Ordovician

crystallization ages. This anorthosite differs in texture and composition depending

on location, that may be the result of its multi-stage metamorphic and/or intrusion

history. Charnockitic rocks north and south of the PCSZ also differ geochemically.

For example, north of the PCSZ, these rocks become more calcic with increasing

SiO2 contents, whereas those to the south become alkali-calcic.