Fig. 2

The calcite-cemented chert breccia: a angular chert clasts and smaller microsparitic clasts in predominantly xenotopic sparite with relicts of a not completely replaced and recrystallised intrapelmicritic matrix (XPL: LA 4.4 mm). b The chert clasts partly replaced by calcite in xeno- to hipidiotopic sparite (XPL: LA 2.34 mm). c The chert: inclusion of less silicified biomicrite with radiolarians and opaque minerals (pyrite) in microquartz with small inclusions of not completely replaced biomicrite (PPL: LA 4.4 mm). d Lamination in the chert amplified by different degrees of silicification and inclusions of not completely replaced limestone with radiolarians, sponge spicules and opaque minerals (pyrite) in darker laminae (PPL: LA 4.4 mm). e Chert—microquartz with radiolarians, sponge spicules, euhedral crystals of pyrite and dolomite replacing microquartz (PPL: LA 1.17 mm). f Same as e (XPL: LA 1.17 mm). g Chert laminae in stylolitic contact enriched with opaque minerals cut by veins filled by elongated mega- and microquartz (XPL: LA 4.4 mm). h Chert—microquartz with inclusions of not completely replaced limestone with oxidised pyrite, radiolarians and some euhedral crystals of dolomite replacing microquartz (PPL: LA 1.17 mm). Key: PPL plane-polarised light, XPL cross-polarised light, LA longer photo axis