The Lavrion mining district of Attica, Greece, is one of the oldest mining areas of the world. In present master’s thesis investigations on three minerals from this area are presented. The samples were especially studied by single-crystal X-ray diffraction as well as by infrared and Raman spectroscopy. The formula of guérinite, was revised, based on a structure refinement in space group P21/n, with unit cell parameters a = 17.631 (2), b = 6.731 (1), c = 23.388 (3) Å, β = 90.69 (1)°, V = 2775.2 (6) Å3, R1 = 0.051, wR2 = 0.094, Z = 4. Bismoclite BiOCl was analyzed in space group P4/nmm with the following cell parameters a = 3.887 (2), c = 7.357 (5) Å, Z = 2, and V = 111.16 (14) Å3, and refined to R1 = 0.013, wR2 = 0.036. Further, there is a contribution in the description of the new mineral tzeferisite, the results of the single-crystal X-ray diffractometry in space group Rc are a = 8.369 (12), c = 67.794 (14) Å, V = 4112.5 (14) Å3, Z = 6, R1 = 0.036, wR2 = 0.089.
The Lavrion mining district is situated in the southeast part of the Attika peninsula, Greece. The mining area extends around 150 km2 divided into several districts (e.g. Kamariza, Plaka, Lavrion). Athens, the capital of Greece, is located 50 km northwest of the Lavrion mining district (Figure 1). The Lavrion stratigraphy is believed to have formed about 5 million years ago by tectonic uplift associated with variations in paleoclimate (Voudouris et al., 2021).
The sample material for my studies was provided by mineralogist Branko Rieck (B.R.), Austria, who has been travelling to the Lavrion area for decades, exploring, surveying and investigating the old mines and new outcrops. He regularly brings back new sample material leading to the discovery of new mineral species (Rieck, B. 2012; Rieck et al., 2018; Rieck et al., 2020c; Rieck et al., 2022).
Guérinite Ca6(HAsO4)3(AsO4)2•10.5H2O (Figure 2) was collected from a banded, vein-type mineralization from the Plaka mine No. 145 on 12th April 2019. The veins known as “vein 80” or “Filoni 80” are up to two meters wide and extend 1 km from East to West between Plaka and Adami Valley (Conophagos, 1980; Skarpelis, 2007; Voudouris, et al., 2008). Alteration of hydrothermal hornfels and skarnoids are rich in Pb-As-Sb-Zn-Cu-Ag sourced from a contact metamorphic zone. The mineralogy of the oxidation zone comprises rauenthalite, marcasite, pharmacolite, arsenopyrite, chalcopyrite, sphalerite, pyrite, calcite, fluorite, quartz (Rieck, B. & Rieck, P. 1999; Wendel et al., 1999a; Wendel et al., 1999b; Skarpelis 2007; Voudouris et al., 2008; Rieck et al., 2018).
Agios Konstantinos is located in the northwestern part of Lavrion mining area, were B.R. found bismoclite BiOCl in the Jean Baptiste mine on 26th April 2014 (Figure 3). The small mine is connected by shafts to a more profitable winding shaft of the Serpieri mine. The few stockpiles indicate a low economic outcome from mining. The Jean Baptiste shaft is known as a locality for adamine Zn2(AsO4)(OH) and carminate PbFe3+2(AsO4)2(OH)2.
Tzeferisite CaZn8(SO4)2(OH)12Cl2•9H2O (Figure 4), identified as a new mineral species (IMA no. 2022-094) (Rieck et al., 2023), was collected from the small Ary mine in Dimoliaki on 2nd November 2021. The Ary mine is characterized by a carbonate-replacement Pb-Zn-Ag mineralization (Skarpelis, 2007; Voudouris et al., 2008a,b; Skarpelis & Argyraki, 2009; Bonsall et al., 2011; Voudouris et al., 2021). In the ore-poor mine, tzeferisite is associated with sphalerite, galena, greenockite, hemimorphite, gypsum, calcite and dolomite.
Figure 3. Locality of bismoclite in the Jean Baptiste mine, April 2014. © Branko Rieck 
Figure 4. Spot of tzeferisite in the Ary mine, November 2021. © Branko Rieck
Loading…
Reload document 
Open in new tab