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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)
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Photomicrograph approximately 400 microns across (plain light, red carbonate stain) showing micrite and minor sparry calcium carbonate cementing silicate-sand grains in nodule 1.
(click image to zoom)



Cemented tubular sandstone suggesting horizontal fingered flow
(nodule 2)
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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.
(click image to zoom)



Cemented sandstone suggesting anastomosing three-dimensional flow
(nodule 3)
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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.
(click image to zoom)



Stage III plugged pedogenic calcium-carbonate horizon.
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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.
(click image to zoom)



Previous < Navigate the Geologic Odyssey > Next
Definitions | Geologic setting
Field observations | Laboratory observations | Hypothesis
Develop a semi-quantitative model to test the hypothesis
Discussion and variations | Abstract | References