The frequency of authigenic megaquartz in thin sections of Mesozoic carbonate rocks makes it possible to estimate the relative degree of thermal exposition of the compared tectonic units. The following groups were distinguished in the Western Carpathians: 1 — unaffected complexes (Pieninicum, Silicicum), 2 — affected by intensive diagenesis (pre-metamorphic stage — e.g. Krizna Nappe), 3 — anchimetamorphosed (part of Tatricum) and epimetamorphosed complexes (e.g. Borinka Unit). Dating of the origin of authigenic megaquartz was derived from its relation to compaction, cementation, lithification, dolomitization, microstylolites, veinlets and metamorphism. The regional distribution of a special authigenic quartz type with zonally arranged inclusions proceeding from an exotic source was traced in the younger sediments.