Abstract
Presents geochemical data for the metamorphic cordierite-orthoamphibole rocks that occur in the Early Proterozoic Svecofennian supracrustal rocks at Orijarvi, Finland, and associated cummingtonite-biotite-plagioclase gneisses. The protoliths for COR and CBP were chlorite-quartz-sericite schists produced from basaltic to rhyolitic precursors by interaction with heated seawater prior to metamorphism. This resulted in a gain of Mg, and a loss of Ca and Sr (by plagioclase dissolution), Variations in Eu abundance, which could be enhanced by alteration, more likely record feldspar fractionation in the igneous environment. Subsequent regional metamorphism of these altered materials produced the observed mineral assemblages. -from Authors
| Original language | English |
|---|---|
| Pages (from-to) | 545-559 |
| Number of pages | 15 |
| Journal | Journal of Geology |
| Volume | 100 |
| Issue number | 5 |
| DOIs | |
| State | Published - 1992 |