Crystallographic orientations of structural elements in skeletons of Syringoporicae (tabulate corals, Carboniferous): implications for biomineralization processes in Palaeozoic corals

摘要: The crystallographic orientation of structural elements in skeletons representatives Carboniferous Syringoporicae (Auloporida) has been analysed by scanning electron microscopy (SEM), petrographic and backscatter diffraction (EBSD) on specimens from the Iberian Peninsula. tabulate corals consist biogenic calcite crystals, their microstructure is composed lamellae, fibres granules, or a combination these. Independent microstructure, c-axis oriented towards lumen, quasi-perpendicular to growth direction skeleton (perpendicular morphological axis parallel fibres). Most phaceloid taxa have turbostratic distribution, as response prevent cleavage crystals. Cerioid some corals, whose conditioned wall elements, do not exhibit distribution. Wall are determined biology each taxon. Holacanth septal spines arranged cone-shape structure, sometimes clamped external part corallite show complex crystallography. Monacanth spindle shaped bundles fibres. Tabulae lamellae. Their development depends position epithelium case. Shared walls formed two independent corallites with median lamina, granules; these between that corallites. derived coordinated stepping mode growth, similar other groups organisms such molluscs scleractinians. nucleation formation packages co-oriented microcrystals suggest mineral bridges competitive crystal. pattern suggests divided into main components: horizontal lumen vertical top.