Clinopyroxenes from metasomatized spinel-peridotite mantle xenoliths from Nemby (Paraguay): crystal chemistry and petrological implications

Authors
Princivalle, F Tirone, M Comin-Chiaramonti, P
Citation
F. Princivalle et al., Clinopyroxenes from metasomatized spinel-peridotite mantle xenoliths from Nemby (Paraguay): crystal chemistry and petrological implications, MINER PETR, 70(1-2), 2000, pp. 25-35
Citations number
23
Categorie Soggetti
Earth Sciences
Journal title
MINERALOGY AND PETROLOGY
ISSN journal
09300708 → ACNP
Volume
70
Issue
1-2
Year of publication
2000
Pages
25 - 35
Database
ISI
SICI code
0930-0708(2000)70:1-2<25:CFMSMX>2.0.ZU;2-H
Abstract
The Nemby mantle xenoliths are represented by spinel peridotites variably a ffected by "metasomatic processes" in Proterozoic times (1.2-0.5 Ga). Clino pyroxene compositional variations mainly reflect variably degrees of basalt extraction and mantle "metasomatic processes". Clinopyroxene crystal chemi stry allows to estimate the equilibration pressure by V(Cell) and V(M1) rel ationship. The investigated clinopyroxenes yielded a pressure range of 12-1 8 kb. Therefore, the Nemby xenoliths we representative of about 20 km thick ness of subcontinental lithospheric mantle of the South America platform at Tertiary times (ca. 46 Ma).