Ocean Reef Park is a beach park on Singer Island, a barrier island/peninsula on the east coast of Florida in Palm Beach County. Like Blowing Rocks Preserve, it also has a notable exposure of the Anastasia Formation. It is roughly 15 miles south of Blowing Rocks. An overview of the Anastasia Formation and map of its extent are in my post on Blowing Rocks Preserve. The Anastasia here is significantly more weathered and eroded than Blowing Rocks. The pockmarked texture is much more rounded, similar to the southern end of the Blowing Rocks exposure where it grades into the sand. The rock appears to consist of more quartz sand grains and less shell fragments, and the shell fragments that are present are finer. The distinctive rod-like bioturbation, so pervasive at Blowing Rocks, is absent here.
The weathered surface of the exposure.
The dissolution pits have expanded, eroding away much of the surrounding rock and leaving only small peaks between pits.
Dissolution pits have eroded out at low points where water collects and flows, forming rills.The exposure grading into the surf, beach sand filling in the weathered pits and rills.
A lower point of the exposure to the north where its surface is at the summer low tide line. Small, pyramid-shaped remnants dot the heavily weathered and eroded surface. A close up of the texture of the rock, showing primarily quartz sand grains cemented with carbonate mud. Life on the rocks.
Solution pipes dissolved through the formation.A dissolution pit actively filling with shell fragments. If the fragments sit in the water, will the solution become super saturated and will calcium carbonate recrystallize, cementing the fragments and lithifying into coquina?
Dissolution pits that have filled with shell fragments, especially oyster shells, then have become lithified by calcium carbonate cement, appearing to answer my earlier question. Would these be classified as actively forming coquina? It’s an interesting feature that I think could warrant further study. The “dissolution pit coquina” seems to be more resistant to weathering than the surrounding lithology.
A collapsed sea cliff. The wave-cut notch eroded further and further landward, and the overhanging sea cliff collapsed under its own weight once it lost support.More collapsed sea cliffs in the surf, the wave-cut notch is visible on the right side of the photo.What I believe are boulders from past collapsed sea cliffs on the northern limit of exposure. This line of boulders further landward marks where a past shoreline was, showing a drop in sea level (regression) since that time.
Concave pattern from beach drift erosion and wave-cut notches visible in the exposure above the surface. This concavity can also be seen in the wave-cut platform under the surface as well.
John Harris 