9 SYMPOSIUM I: EVOLUTION O THE DEPOSITIONAL SYSTEMS MINERALOGICAL CHARACTERIZATION increase of siliciclastic sedimentation with the progressive shallow- O LYSCH SEQUENCES O THE SE ALPS ing of the basin from deep-sea to delta facies. In the Vipava lysch (VI) carbonates are predominant. In the lysch of Brkini (BK) the AND OUTER DINARIDES (NE ITALY, mineral content is similar to that of the coeval sandstones in the JB. SLOVENIA, CROATIA) Dolomite appears only in the molasse samples. In the Istrian Basin (IB) no clear trend is noticed. In the western part the siliciclastic material content is higher than in the eastern part (ig. 2). A. ALBERTI1, D. LENAZ 1, . PRINCIVALLE 1 As for heavy minerals, Cr-spinel, garnet (pyralspite and gran- and G. TUNIS 2 dite series), zircon, tourmaline, rutile, pyrite, chloritoid, pyroxene (opx and cpx), staurolite and amphibole were identified, but their 1Dipartimento di Scienze della Terra, Via Weiss 8, 34127 Trieste, Italy 2Dipartimento di Scienze Geologiche, Ambientali e Marine, Via Weiss 2, 34127 Trieste, Italy; *
[email protected] Key words: lysch, X-ray powder diffraction, heavy mineral assemblage, source areas. Introduction An extensive lysch complex of Late Cretaceous to Early Ter- tiary age outcrops in north-eastern Italy, western Slovenia and Is- tria (Croatia) (ig. 1). The rock sequences belong to different dep- ositional basins and have different ages. Sedimentation in the basins of the northern part of the complex (Slovenia and riuli) occurred from the Maastrichtian to Middle Eocene (Engel 1974; Tunis & Venturini 1989), while in the southern part (Trieste, SW Slovenia and Istria) it took place from the Middle to Late Eocene (Marincic et al.