A micro-analytical approach to partition coefficients in plagioclase and clinopyroxene of basaltic sills in Serra Geral Formation, Paraná Basin, Brazil
| Autor: | Léo Afraneo Hartmann, Wilson Wildner, Thomas Theye, Leonardo Cardoso Renner, Hans-Joachim Massonne |
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| Jazyk: | angličtina |
| Rok vydání: | 2011 |
| Předmět: |
Basalt
geography geography.geographical_feature_category lcsh:QE1-996.5 Geochemistry Serra Geral Formation Electron microprobe engineering.material Partition coefficient lcsh:Geology Augite Sill clinopyroxene Pigeonite engineering General Earth and Planetary Sciences Plagioclase Partition (number theory) plagioclase LA-ICP-MS Geology |
| Zdroj: | Brazilian Journal of Geology v.41 n.2 2011 Brazilian Journal of Geology Sociedade Brasileira de Geologia (SBGEO) instacron:SBGEO Brazilian Journal of Geology, Vol 41, Iss 2, Pp 263-289 |
| Popis: | In the present study, detailed micro-analytical data (major and trace elements) in minerals from sills of Serra Geral Formation represents the fi rst attempt to evaluate the partition coeffi cient of Sc, Ti, V, Cr, Co, Ni, Cu, Zn, Rb, Sr, Y, Zr, Nb, Mo, Cs, Ba, REE, Hf, Ta, Pb, Th and U among coexisting plagioclase, augite and pigeonite from 12 tholeiitic basaltic sills along the eastern border of the Parana Basin, Brazil. These 12 samples come from Rio Grande do Sul, Parana, Sao Paulo and Goias states. Plagioclase/melt partition coeffi cients K D were determined in core, intermediate and rim zones using LA-ICP-MS and the results were compared with the variations of the elements Ca, Al, Na and Si in those areas. Partition coeffi cients of Sr and Eu decrease with the increase of Ca concentration in plagioclase. A reduction in temperature and consequently a rise in Na and Si levels increase the partition coeffi cients of Sr and Eu at the rim of mineral The K D of Ni and V in clinopyroxene has positive correlations with Mg 2+ , Ca 2+ and Al 3+ due to higher concentrations of those elements at the core and lower concentration towards the rim and negative correlations of K D of Sc, Cr, Co, Pb and Lu, due to preferential substitutions by Fe 2+ in sixfold coordination. The use of LA-ICP-MS and EPMA made possible the chemical quantifi cation of major and trace elements and the determination of partition coeffi cients in coexisting plagioclase and clinopyroxene in basaltic melts. |
| Databáze: | OpenAIRE |
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