Fig. 2 in Nanostructural and geochemical features of the Jurassic isocrinid columnal ossicles

Fig. 2. Micro− and nanostructural organization and basic geochemical characteristics of the Middle Jurassic (Middle Bathonian) isocrinid columnals from Gnaszyn clay pit, Poland. A. Transverse section of the columnal (beige in color) of Chariocrinus andreae (Desor, 1845), GIUS 8−2570 (A2 enlargement) in optical microscope (A1, A2) and in SEM back−scattered electron (BSE; A6, A7) images. Nanogranular organization of the stereom in AFM images (A4, A9 height−2D, and A5, A10 deflection images respectively; contact mode; buffered pH = 8, ammonium persulfate 1%, 10 min.). B. Slightly oblique section of the columnal (black in color) of Balanocrinus berchteni Hess and Pugin 1983, GIUS 8−2510 (B2 enlargement) in optical microscope (B1, B2) and in BSE (B6–B8) images. Note a clear border between stereom with distinct nanogranular texture and inter−stereom deposits with more flat surface (parallel lines are polishing scratches); B4, B10 height, and B5, B11 phase images, respectively. BSE mode enhances atomic number contrast; elements with lower atomic numbers appear darker, those with higher atomic numbers appear lighter (e.g., framboidal pyrite grains, B7). Spot geochemical analyses of the stereom (A3, B3) and inter−stereom deposits (A8, B9).