Exercises in carbonate Petrology

chertification (silicification)

1. (B/109/Pen/Tx-BTI) (Marble Falls) shows infilling of voids by chert. Sketch.

2. (B/110/Pa/NMx-BRJ) (Dry Creek) shows chert filling micrite envelopes and beginning to replace calcite fossils. Sketch.

3. (B/111/D/Tx-BAM) (Edwards 1st) shows chert replacing everything except micrite envelopes.

4. (B/113/Eo/Ut-CND) shows fossils unreplaced but cemented by quartz. Sketch.

5. (B/112/Pm/NMx-BUJ) shows fusillinids replaced by chert but micrite matrix remains.

6. (O/41/Ord/Pa) Silicified oolite from the Ordovician of Pennsylvania. Describe the original ooid structure. What aspect(s) of the original structure has silification preserved? Describe and account for this sample's porosity.