skip all navigation
skip banner links
skip primary navigation

A Geologic Odyssey: Laboratory Observations

  1. Calcium carbonate amounts and densities within nodules
  2. Thin sections
Cemented tubular sandstone with calcified root mat preservation in thin section (nodule 1).
Photomicrograph approximately 400 microns across (plain light, red carbonate stain) showing micrite and minor sparry calcium carbonate cementing silicate-sand grains in nodule 1.
Cemented tubular sandstone suggesting horizontal fingered flow (nodule 2).
Photomicrograph approximately 400 microns across (plain light, red carbonate stain) showing micrite around grains and sparry calcium carbonate in former pores between silicate-sand grains in nodule 2.
Cemented sandstone suggesting anastomosing three-dimensional flow (nodule 3).
Photomicrograph approximately 1.2 mm across (plain light, red carbonate stain) showing oriented micrite around grains and sparry calcium carbonate in former pores between silicate-sand grains in nodule 3. Note secondary porosity along edges of some grains.
Stage III plugged pedogenic calcium-carbonate horizon. (nodule 1).
Photomicrograph approximately 400 microns across (plain light, red carbonate stain) showing micrite, clay, and Mn-Fe hydroxides in concentric bands around grains (oolitic calcitans) in Stage III calcium-carbonate horizon.