Journal of Geological Society of India (Online archive from Vol 1 to Vol 78)

Open Access Open Access  Restricted Access Subscription Access
Open Access Open Access Open Access  Restricted Access Restricted Access Subscription Access

Rare Earth Element Geochemistry of the Munnar Carbonatite, Central Kerala


Affiliations
1 Centre for Earth Science Studies, P. B. 2235, Sasthamangalam, Trivandrum 695010, India
2 Departmento de Processos Especiais-MEC, Institute de Resquisas Energ. e Nucleares, Caixa Postal 11049-Butanta, Sao Paulo, Brazil
     

   Subscribe/Renew Journal


Rare earth element abundance in carbonatite associated with the 740 Ma old alkaline complex of Munnar is reported. High values of La (up to 232 ppm) and Ce (up to 261 ppm), moderate Sm (upto 11 ppm), with low Tb (up to 1.1 ppm), Yb (upto 3 ppm) and Lu (up to 0.6 ppm) are observed, comparable with similar values for carbonatites from other regions. The chondrite normalised patterns exhibit a steep slope from LREE to HREE, with (La/Lu)cn ranging upto 191. A genetic model involving CO2 degassing from the mantIe and ion exchange reactions with deep crustal rocks is envisaged, with the carbonatites probably representing a late immiscible fraction that separated from a polymerized alkali silicate melt. REE geochemistry of the carbonatite substantiates the view of a Late Precambrian alkaline magmatic regime in this part of the Indian Shield.
Subscription Login to verify subscription
User
Notifications
Font Size

Abstract Views: 499

PDF Views: 4




  • Rare Earth Element Geochemistry of the Munnar Carbonatite, Central Kerala

Abstract Views: 499  |  PDF Views: 4

Authors

M. Santosh
Centre for Earth Science Studies, P. B. 2235, Sasthamangalam, Trivandrum 695010, India
P. K. Thampi
Centre for Earth Science Studies, P. B. 2235, Sasthamangalam, Trivandrum 695010, India
S. S. Iyer
Departmento de Processos Especiais-MEC, Institute de Resquisas Energ. e Nucleares, Caixa Postal 11049-Butanta, Sao Paulo, Brazil
Marina B. A. Vasconcellos
Departmento de Processos Especiais-MEC, Institute de Resquisas Energ. e Nucleares, Caixa Postal 11049-Butanta, Sao Paulo, Brazil

Abstract


Rare earth element abundance in carbonatite associated with the 740 Ma old alkaline complex of Munnar is reported. High values of La (up to 232 ppm) and Ce (up to 261 ppm), moderate Sm (upto 11 ppm), with low Tb (up to 1.1 ppm), Yb (upto 3 ppm) and Lu (up to 0.6 ppm) are observed, comparable with similar values for carbonatites from other regions. The chondrite normalised patterns exhibit a steep slope from LREE to HREE, with (La/Lu)cn ranging upto 191. A genetic model involving CO2 degassing from the mantIe and ion exchange reactions with deep crustal rocks is envisaged, with the carbonatites probably representing a late immiscible fraction that separated from a polymerized alkali silicate melt. REE geochemistry of the carbonatite substantiates the view of a Late Precambrian alkaline magmatic regime in this part of the Indian Shield.