Page 79 - Carbonate Sedimentology and Sequence Stratigraphy
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P
Fig. 4.15.— Pendent cement (P) under a crinoid fragment, subsequently encased by turbid marine cement. Convincing evidence
of exposure is created by the combination of pendent cement geometry, brown stain from humic substances and the decrease in
the carbon-isotope ratio at this level (see Fig. 4.14). Pendent-cement geometry by itself indicates supratidal or terrestrial conditions.
Carboniferous, NE Spain. field of view is 5 mm across. After Immenhauser et al.(2002).
a
Fig. 4.16.— Thin section of layered calcrete (or caliche) - a typical carbonate soil. Upward bending of layers, wiggly cracks and
alveole, a, filled with whitish calcite spar indicate early cementation. Dark iron oxides/hydroxides at the top. Exposure surface in
mid-Cretaceous Nahr Umr Formation, Oman. After Immenhauser et al. (2000).
