Ardennite-bearing mineral association related to sulfide-free ores with chalcophile metals at Nežilovo, Pelagonian Massif, North Macedonia

Among numerous minerals determined at Nežilovo, Pelagonian Massif, North Macedonia, ardennite-(As) has been discovered in two different associations and studied by means of optical microscopy, electron microprobe analysis (EMPA), and single-crystal and powder X-ray diffraction methods. The refractive indices of ardennite-(As) from Nežilovo are α=1.537(2), β=1.579(1) and γ=1.741(1), where γ corresponds to the c direction. The optical axial angle is 2Vx=49(1)∘. EMPA of the investigated samples yields the following empirical formulae: [Mn3.272+Ca0.73]Σ4.00[Al4.18Mg1.24Fe0.29Mn0.193+Zn0.10]Σ6.00(Si4.73Al0.27)Σ5.00(As0.96Si0.03V0.01)Σ1.00O22 [OH5.36(H2O)0.64]Σ6.00 for ardennite-(As) and (K0.95Na0.04Ba0.02)Σ1.01(Al1.44Fe0.303+Mg0.20Mn0.03Ti0.02 Zn0.01)Σ2.00(Si3.21Al0.79O10) (OH1.97O0.03)Σ2.00 for the associated red mica. The unit cell parameters of ardennite-(As) determined by X-ray powder diffraction are a=8.757(2) Å, b=5.836(2) Å, c=18.578(2) Å and V=941.97 Å3. The unit cell parameters of ardennite-(As) were also determined by single-crystal X-ray diffraction and are a=8.760(1) Å, b=5.838(1) Å, c=18.582(2) Å and V=950.30 Å3. Regularities of isomorphism in ardennite-related minerals are discussed. The presence of ardennite-(As) in association with 2M1 and 3T phengite polytypes provides evidence for three separate stages of formation. Conditions at which ardennite-(As) crystallized have been estimated based on compositional features of associated micas.

The association of oxygen-bearing minerals of chalcophile elements in the orogenetic zone related to the “mixed series” complex near Nežilovo, Republic of Macedonia

<p>New data are obtained for minerals from metasomatic rocks of the orogenetic zone related to the “Mixed series” metamorphic complex situated in the Pelagonian massif near the Nežilovo village, about 40 km SW of Veles, Republic of Macedonia. A specific feature of these rocks is the concentration of chalcophile elements (S, As, Sb, Zn, Pb) mainly in the form of oxides and oxysalts, whereas sulfides and sulfosalts are present only in trace amounts. Rock-forming and accessory minerals have been characterized by electron microscopy, electron mictoprobe analyses and in part by X-ray diffraction and IR spectroscopic data. Some of described minerals (Sb-rich analogue of zincohögbomite-2<em>N</em>6<em>S</em>, hydroxyplumbobetafite, Fe³⁺-analogue of coronadite) are potentially new mineral species. Some genetic aspects of the formation of oxidized As-Sb-Zn-Pb-rich rocks are discussed.</p>

High-pressure metamorphism between the pelagonian Massif and Vardar Ophiolite Belt, Yugoslavia

A reported occurrence of metamorphic rocks containing sodic pyroxenes, in the transition zone between the Pelagonian Crystalline Massif and the Vardar Ophiolite Belt, in Macedonia, Yugoslavia, has been re-investigated, and pyroxenes, micas, plagioclase, and clinozoisite analysed by microprobe. The presence of the high-pressure metamorphic assemblage quartz + omphacite+albite is confirmed, giving the first definite indication of blueschist-facies metamorphic conditions in Yugoslavia.

Existence d'une serie cretacee allochtone dans la region occidentale du Parnasse (Grece)

There are two distinct Cretaceous series in the western Parnassus massif in Greece. The Parnassus series corresponds to a zone of shallow calcareous sedimentation, which was emergent for a considerable period of time, during which bauxites were formed. The Jerolekas series is characterized by detrital material derived from the Pelagonian massif and contains flyschlike zones. It constitutes an allochthonous tectonic unit overthrust from the east on the Parnassus series.