The 11.6 to 9.5 Ma Serifos pluton intruded schists and marbles of the Cycladic Blueschist unit, causing thermal metamorphism, the development of magnetite Ca-exo- and endo-skarns and the formation of low-temperature vein and carbonate-replacement ores. Potentially, the most important ores occur in the Moutoulas prospect where the mineralization in retrograde skarn and quartz veins culminated with the deposition of native bismuth. A combination of fluid inclusion microthermometry and isotope geothermometry suggests that the Moutoulas mineralization formed at a hydrostatic pressure of ~100 bars, from moderate-to-low temperature (~190–250 °C), and low-salinity (1.3–5.6 wt% NaCl equivalent) fluids. The calculated δ³⁴SH₂S compositions are consistent with the ore fluids having been derived from the Serifos pluton. Bismuth mineralization is interpreted to have occurred as a result of wall-rock interaction and mixing of a Bi-bearing ore fluid with meteoric waters. Native bismuth and bismuthinite deposited at ~200 °C, near neutral pH (6.5), low fS₂ (< –16.5), and low fO₂ (< –44). Supergene alteration in Serifos led to the oxidation of native bismuth to bismite and bismutite.

The promotion of geological heritage can significantly contribute to geoeducation. As geosites are areas that can be visited by everyone and not just experts on the field, a good comprehension of the processes under which they were formed can improve their understanding of the Earth in general. In this work, we have selected two Greek regions, namely Samaria Gorge (Crete) and Mount Pentelicus (Attica), and their sites of geological interest were mapped. Subsequently, some georoutes are proposed, covering both these sites and other locations of cultural, historical, archaeological, and/or religious interest. Through a detailed description of each site and its georoutes, we intend to promote the two areas’ geological heritage on the one hand, and contribute to the development of geoeducation on the other hand. For this purpose, we have also created an online story map and a Virtual Reality (VR) application for each one of them, both addressed to the general public.