January 4: Life's a Beach

Steven Dutch, Professor Emeritus, Natural and Applied Sciences, University of Wisconsin - Green Bay

After digging a compost pit for food waste, it soon became apparent that Morpho butterflies love pineapple.
Police stops are common. Mostly it's a serious crackdown on speeding but our rental vehicles got stopped for out of date temporary plates. A little mordida was also not out of the question.

Playa Leona

On the way in to Playa Leona. Believe it or not, there was a serious reason to come here. One purpose of the course was to compare different approaches to conservation in Costa Rica. This is a private sanctuary that offers serious nature walks (canopy tours and the like) and conservation but supports it and attracts visitors with resort activities.
This is the publicly accessible beach.
Picking up survival essentials for a grueling day on the beach.
Jaime Kozloski and Kelly Hirsch
Saving the rain forest through miniature golf.
Waiting for the shuttle.
The central resort complex.

Below: views on the way to the private beach at Playa Blanca. Playa Blanca is part of the Playa Leona complex but restricted access.

Signal flags for wave conditions.

Below: The main resort center at Playa Blanca.

Vigorous research seminar in progress.

Playa Blanca Beach

Looking north along the beach.
Looking south along the beach.
Looking west to the Nicoya Peninsula.
Our group plunged into their research.
Seminar on oceanography in progress.
Sign at the north end of the beach:


Don't cross when the tide is rising

You run the risk of being trapped.

Ripple marks exposed by the retreating tide
A small spring emerging on the beach. Small sand boils were visible erupting under the water.
Same spot half an hour later after the tide had fallen still further.

The Headland

At the north end of the beach is a rocky headland. The flat terrace at the base is a former wave-cut platform, recently uplifted.
The rocks here are Tertiary siltstones.

Below: deep, joint-controlled slots cut the wave cut terrace at regular intervals and make rounding the point a lot harder than it looks from a distance.

A notch provides an easy path to the far side of the rocks.
Left and below: views on the far side of the headland.
Although there's no coral on the beach, beyond the point coral fragments were abundant.
Left: mineralized fractures erode more slowly than the surrounding rock and stand out in relief.

Below: the wave-cut platform on the far side of the point.

A mollusk-bored rock.

Below: cacti on the cliffs.

From a distance, it looks like an easy walk around the point, but deep, joint-controlled slots like this occur every fifty yards or so. On both sides, some are dangerous enough to block progress.
Below: the tracks in the silt were made by snails and other bottom dwellers.
Above: at high tide the sea cave and surf block the path (above), but when the tide goes down (left) it's an easy crossing.
Below: Former sea cliff and uplifted terrace. The prevailing wind twists the trees.
Above: fracture zones in the rocks.

Left and below: mineralized fractures standing out in relief.

Left and below: breaking waves on the edge of the terrace.
This side view shows a nice cross section of the former sea cliff and elevated terrace.
Left and below: wave action swirls sand and pebbles around in crevices, eventually abrading potholes.
Slickensides on this slab indicate fault motion.
A colorful crab washed ashore.
Nearly horizontal layers (left) are cut by a wide shear zone (right two thirds of the picture).
End of the line. There doesn't seem to be any safe way to cross this slot regardless of the state of the tide.


Coatis are close relatives of raccoons and just as brazen moochers. Despite signs warning visitors not to feed them, people do, and so a pack patrols the seawall. The youngsters are tan and look at first glance like cats except for the long snout.
Does it get any more brazen than this?

South End of the Beach

Contorted bedding like this at the south end of the beach generally indicates submarine slumping of loose sediment.
Fugu, anyone? A puffer fish on the beach.

Below: the contemporary wave-cut platform

Dark heavy minerals concentrated by wave action and backwash.


This pelican was a constant fixture. Here he dives and gets a fish.
Frigate bird.


Left and below: bougainvillea
Coconut palm

After Hours

♫ Wastin' away in margaritaville... ♪

Below: twilight on the beach

Some people went to dinner in style. Samantha Olsen gets a ride from Greg Sheier, while Phil Hahn approves.
Dinner at a seafood buffet.
We were welcomed home by one of the locals.

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Created 18 January 2008, Last Update 11 June 2020