Figure 7-15. Subtle layer boundary in calcite (C) defined by scattered clusters of scalenohedral calcite crystals (red arrows). Note that absence of such clusters leaves no evidence of a layer boundary at all (blue arrow).
A corresponding image provides a matching view in cross-polarized light. In that image, columnar calcite fabric not evident here is made visible. Photomicrograph was taken in plane-polarized light; field of view is 1.9 mm wide. Carlsbad Caverns, New Mexico, U.S.A.; Georgia Giant Stalagmite; thin section CB17. Sample colected by Dr. George A. Brook. |
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