Skeletal Microstructure of Paleozoic Stromatoporoids and Its Mineralogical Implications

Treatise Online, no. 6, Part E, Revised, Volume 4, Chapter 9D: Microstructure and Mineralogy of Paleozoic Stromatoporoidea

“…1,1-2), like the crystals described as bossulure by laFuSte (for example, laFuSte & FiSCher, 1971) from ultrathin sections in many corals. The alignment of elongate crystals may impart a crude fibrosity to the structural element observed in the SEM (Stearn & Mah, 1987). It has been described in such Paleozoic stromatoporoids as Hammatostroma, Amphipora, and Anostylostroma ( Fig.…”

“…2,2). This effect could be caused by the refraction of light around minute voids, such as fluid inclusions, as postulated by Stearn and Mah (1987).…”

“…Stearn (1977) described specimens of Stromatopora with cellular microstructure, which showed traces of a radial arrangement of elongate crystals, suggesting they were remnants of spherules. These radial structures are rare, however (Stearn & Mah, 1987), and may be a diagenetic product unrelated to original microstructure. In stromatoporoids of well-preserved cellular microstructure, the cellules are formed by calcite in coarser crystals than those in the more opaque areas of the structural elements and like those in the gallery filling (Fig.…”

“…ClarK (2005) found organic matrix remnants dispersed throughout the recrystallized calcite skeleton of an unidentified stromatoporoid. Stearn and Mah's (1987) investigations with the SEM showed that the specks were small cavities that they interpreted as filled with fluid inclusions (see below).…”

“…1,1-2; Fig. 2,1; Stearn, 1977;Stearn & Mah, 1987). Although galleries are almost universally filled with calcite, Kano and lee (1997) have described Ordovician specimens with fluorite in the galleries.…”