Sunday, March 21, 2010

Oolite Highway

Oolite is found in certain parts of the world and the Lower Keys is one of those places. It's not found north of Big Pine Key even though the term "Lower Keys" is usually used to indicate all the islands south of the Seven Mile Bridge. However because oolite, known as egg stone -derived from the Greek for egg- nestles among the limestone only from Big Pine south and it creates holes like these:The limestone rock that formed the Keys is similar to the rock that created the Bahamas which makes these islands much more similar geologically to our island neighbors than to the sandy mainland of Florida. Oolitic limestone looks something like this:
And I titled this essay the way I did because this is what one of several wide pathways through the pine trees looks like in the BPK (Big Pine Key) deer refuge:From Virginia Key, off Miami the barrier islands are sedimentary limestone, but down here something different happened when these islands were being formed. For some reason calcium carbonate got deposited on these limestone rocks, possibly owing to corals growing on sandy shoals on top of the limestone, then as conditions changed the coral died and became the calcium carbonate deposits. Pick your theory according to various sources I have consulted but the end result is rock that looks like petrified sponge. And where the rock forms shallow bowls rainwater accumulates leaving behind a mud hole during dry season. And some Labradors happen to find these mud holes inexplicably attractive. The dry season came late this winter and these holes were full of delicious tannic water a few weeks ago. Now Cheyenne could find nothing but mud:
She looked hard and long for water:
Entirely satisfying even though there was no water:
From small acorns as it were, above, do large oak trees grow. In this case mangroves and pines. If you needed a spare limestone rock you might find plenty here for your landscaping, except the Feds don't much care for people removing stuff from public land.
More stuff growing out of the oolite holes:
I stuck my camera into a particularly large hole and turned on the flash to see what I might see.
You could break an ankle in one these if you felt like it. People sometimes stick a branch down the hole to alert walkers to their presence. This was a red letter walk.
By the time we stumped back to the car... ...Cheyenne was ready for a rest. And yes, she got a bath and spent the rest of the afternoon in a sulk in the back of the car. I left the car door open and went upstairs for a well earned cup of tea. To each her own.