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Rare earth abundances and origin of some Indian lamprophyres

Published online by Cambridge University Press:  01 May 2009

D. K. Paul  and
P. J. Potts
D. K. Paul
Affiliation:
Geochronology Division, Geological Survey of India, Calcutta, India
P. J. Potts
Affiliation:
Department of Earth Sciences, The Open University, Milton Keynes, England
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Summary

Abundances of rare-earth elements (REE) and Th, Ta, Hf, Sc, Co, Ba determined by instrumental neutron activation analysis show similarity between lamprophyres and other potassic rocks including kimberlite. The Indian lamprophyres have fractionated REE patterns with enrichment of light REE. The light REEs show more variation than the heavy REEs within the group.

Lamprophyres occurring in intimate association with the alkaline basalt may be genetically related. The trace element characteristics of the abundant lamprophyre dykes in granitic terrain are unlikely to be generated by assimilation of alkaline basalt by granitic crust. Small amounts of partial melting in mantle pockets enriched in incompatible elements as a result of metasomatic processes would explain the elemental concentration observed in the lamprophyres.

Type
Articles
Information
Geological Magazine , Volume 118 , Issue 4 , July 1981 , pp. 393 - 399
Copyright
Copyright © Cambridge University Press 1981

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