Retrograde metamorphism in the Klodzko-Zloty Stok area, SW Poland. Textures, physical conditions, and mass transfer
Ferrow, Embaie A.; Baginski, Boguslaw
published: Mar 24, 1998
ArtNo. ESP154017301003, Price: 29.00 €
The overall mineralogical changes that took place when rocks from the Klodzko-Zloty Stok area in SW Poland were metamorphosed from amphibolite to greenschist facies are summarised by: l.72plg + 0.55hbl1 + 0.03cpx + 0.l7ilm + 0.85K + 0.44Mg + 0.35Fe + 5.09H2O + 0.55HCO3- 1.15alb + 0.57bio + 0.55cal + 0.02mus + 0.10preh + 0.02sph + 0.04chl + 0.015hbl2 + 0.71Ca + 0.0l Mn The reaction shows that plagioclase (pig), amphibole (hbl 1), and pyroxene (cpx), primary minerals stabilised during regional metamorphism to amphibolite facies, were replaced by albitic plagioclase, biotite, calcite, prehnite, and chlorite. Retrograde metamorphism to greenschist facies was initiated by a fluid carrying Fe and Mg ions, resulting in an increase in volume by 9.5 %. The fluid temperature during hydration is estimated to be in the range of 290-350 DC; while the appearance of high temperature phases like hypersthene, corundum, and hercynite in hornfelses close to the intrusion suggest that a temperature range of 650-750 DC was locally attained by the influence of the igneous body. The excess metal ions were probably supplied by the intrusive body, whereas quartz was supplied by the breakdown of cordierite to pinnite in the adjacent rocks.