ABSTRACT
The lake Worth Subsea of the Tarantian Age represented the last vestige of the Okeechobean sea, and the culmination of 40 million years of shallow marine deposition in the Everglades area. The original high-magnesium fossils have been altered in place to low-magnesium calcite through the removal of excess magnesium within the meteoric zone. Aragonite is being dissolved currently by meteoric water, and the dissolved calcium carbonate is being redeposited near the site of dissolution as low-magnesium calcite cement. The Key Largo reef crest, however, was largely removed by wave action and dissolution during the Wisconsinan sea level lows, leaving the reef platform and back reef as the only remnants of a once-wider feature. At the Windley key quarry, the encrusting bivalves Chama macerophylla and Spondylus americanus can be seen to have grown on the eroded undersides of some of the massive coral heads.
