Fossils and Tears
13 April 2013 | San Juanico (not Calleta as Sue told the net this morning, lol)
Craig
This was one of our worst anchorages ever. Winds from one direction and seas from the other. The poop-deck was getting pooped so often that Sue and I had to sleep in the forward cabin and listen the the wind howl through the rigging.
The morning brought relative calm and beautiful weather so we decided to explore some of the strange and wonderful geography that is San Juanico. A place that has everything from sandstone to fossil clam beds to lava flows with obsidian Apache Tears. We took our kayak ashore through crystal clear, green-blue water and began our walk at the "yatistas shrine"...a tree covered with signs and artifacts that other visiting yachts had left to commemorate their passage through here. One of the displays was a boat name written in obsidian nuggets. Just behind the tree, Craig spied a vein of shinning material and it turned out to be crystals (maybe gypsum). We collected a few of those, but were really interested in finding the source of the Apaches Tears.
We walked about 200 yards down the beach, collecting shells as we went and noticed that the geology had changed again. There was a gray cliff that looked knobby. On close inspection we discovered that the entire cliff was fossilized clam shells, some of a species that we had never seen in modern times. We took lots of pictures and collected a few shells that were loose at the bottom of the cliff. Craig, still looking for the obsidian moved west into the next geologic bed. The topography here is almost vertical bedding planes because of the severe geologic uplift, so you can go millions of years in time just by walking a hundred feet. There in the cliff was a grey volcanic flow with large grey blobs in it. The blobs contained the obsidian concretion (crystals) that the local people call Apache Tears. After we found them on the ground and in the cliff in sizes from pea to as big around as a dime, we noticed that the local beach was black like the black-sand beaches in Hawaii. The nodules are shaped like blueberries, but are shinny black. They are formed in a grey crystal matrix that was the fist-sized knobs that Craig first noticed in the rock.
Moving on down the beach in the kayak, we discovered another strange thing. A cliff with grey shale-like rock that had sea salt crystals on it. ONLY on the grey shale, not on the adjacent brown rock. Our supposition is that the shale absorbs salt spray and then excretes it at a rate that allows evaporation and deposit of the salt...any other speculations?
As we watched the sunset, we were amazed at the multitude of grebes, a small diving bird with bright red eyes. At home we may see one or two, here we see hundreds. They float on the surface and then all at once, dive below the surface as a group, resurfacing at almost the same time to resume their paddling.
A fun day was finished with a good wine and a pizza and hopefully a calm nights sleep before we leave tomorrow to begin our trip back to La Paz and ultimately home.