Fig. 10 in Palynology and microfacies of Lower Devonian mixed carbonate-siliciclastic deposits in Podolia, Ukraine

Fig. 10. Lower Devonian bivalve−ostracod bioclastic limestone microfacies of the uppermost Ivanye Horizon, Ivanye Zolote locality (see Fig. 3 for the sample location; compare coeval microfacies details from Ustechko in Uchman et al. 2004: fig. 4). Variable but mostly micrite−dominated peloidal−sandy matrix, and variously packed (stacking in some places) skeletal concentrations of originally aragonitic bivalve valves (as moulds) and largely disarticulated calcitic ostracod shells are most numerous. Note a distinctive graded bedding (normal in the lower part and reversed in the upper half) and plane lamination (A, sample I3; close−ups of coquina partings in A2–A4), frequent shelter cavities and geopetal infillings (within gastropod shell, B; sample K15), as well as iron oxide impregnation of the shelly material (largely ostracods) and ferruginized pressure−solution seam (B), and dolomitized internal sediment (dl in D; sample I2). Associated skeletal components include diverse ichthyoliths (Ic, arrowed in C; sample I0), locally abundant small−sized and smooth articulate brachiopods (Br, arrowed in A, note different preservation of brachiopod and bivalve shells in A4) and orthocone nautiloids (Or, note a broken wall chamber, arrowed in D), as well as chaetetid demosponge colonies (cf. Gritsenko et al. 1999; Ch in B2 and C2, rfc, radial−fibrous cement), "vermiform" microconchids (Mi in A3), phosphatic lingulid shells (Li in A2), and conical ribbed tentaculitids (Te in C2).