Paragenetic interpretation of Ti-clinohumite-bearing marblefrom Zorovac Creek, Mt. Moslavačka Gora (Croatia) and itspetrogenesis

This study examines impure grey marble occurring as interlayers in amphibolite and diopside-amphibole schists which belong to the magmatic-metamorphic complex of Mt. Moslavačka Gora in Croatia. The marble is composed mainly of calcite with abundant accessory minerals: dolomite, forsterite, spinel, pargasite, phlogopite, ilmenite, apatite, Ti-clinohumite, tremolite, chlorite, serpentine and talc. Detailed descriptions of mineral assemblages, their textural relationships and mineral chemistry analyses in situ, as well as compositional maps of characteristic mineral assemblages, revealed that the marble experienced at least three different metamorphic stages. These can be summarized as follows: a) the regional metamorphic stage characterised by peak metamorphic stage in granulite facies and a mineral assemblage consisting of calcite + dolomite + forsterite + spinel + pargasite + phlogopite + ilmenite + apatite; b) the stage of subsequent infiltration of an external Ti-rich, fluorinated fluid into the marble giving rise to the origin of Ti-clinohumite, the Ti content of which varies from 0.070 to 0.325 pfu and its XF value, defined as F/(F + OH), is in the range of 0.32 to 0.57; c) the stage of uplift and exhumation of the terrain causing diverse retrograde metamorphic reactions such as the replacement of Ti-clinohumite, spinel and pargasite by chlorite, formation of tremolite on the rims of pargasite and forsterite, as well as the replacement of forsterite by serpentine and talc. Due to the differences in the age determinations of both metamorphisms and magmatic intrusions, good correlation between the occurrence of the Ti-clinohumite bearing marbles of Mt. Moslavačka Gora with those found in surrounding terrains, for instance in Alps (Switzerland/Italy, Austria, Czech Republic) and Rhodope massif (Greece), could not be established at this stage of the investigation.