Galapagos Trip 2023 -- Day 6 -- Floreana Island, Part 2 -- Post Office Bay

After our exploration by panga of the area around Onslow Islet, we proceeded further southwest along the coast and made a wet landing on a green sandy beach in what is known as Post Office Bay.  Yes it really was green, or at least had a greenish tint.  More on that later. 

GPS track of the Day 6 morning adventures on the northern shore of Foreana Island

As seen in the photos below, the setting was quite picturesque. 

Beach at Post Office Bay

Beach at Post Office Bay with La Pinta in the distance

Why is this called "Post Office Bay"?  To answer that, we first we need a little history.  Commercial whaling was a major economic activity in the world in the 18th and 19th centuries. It was driven primarily by the need for whale oil to illuminate homes and to lubricate machines of the Industrial Revolution.  

Whaling begins in the Pacific.  By the latter part of the 18th century competition, trade restrictions, and a significantly reduced Atlantic whale population resulted in exploration of the Pacific as a potential new source of whales.  In 1788, the British whaler Emilia  undertook the first major Pacific whale hunts, finding whales off the South American coast.  That extremely successful voyage prompted many others in Britain and the U.S. to soon follow.  It was found that the nutrient rich waters around the Galapagos Islands as well as a deep water area to the west of the islands were prime locations for whales.

Floreana Island became a major whaling stopover.  Whaling expeditions typically lasted two years or longer.  Floreana Island in the Galapagos became a major stopover for  provisioning of ships.  It was one of the only islands with fresh water and it also had a plentiful source of fresh meat, the tortoises.  Given the description below of the whalers' diet staple, salt meat, it is no wonder ships would go out of their way to seek provisions of fresh meat.

Fresh meat of any kind was indeed a wondrous change for sailors restricted to a diet of salt meat. It is hard to imagine how unpalatable and disgusting salt meat truly was. Beef and pork—and occasionally horse—were chopped up, with no attempt to separate the bones and fat, and then thrown into wooden casks of salt brine where the meat would turn green with age.

Somebody's brilliant idea.  To take advantage of all of these ships stopping at Floreana Island, the whalers setup their own whaler post office. As legend has it, a wooden whiskey barrel was left on Floreana Island in 1793.  Any passing sailor could leave a letter in the barrel, but he also had to check if there was any mail that he might be able to deliver when he returned home.  When he finally reached port he was then responsible to deliver it. This was obviously a very slow mailing system, but it was simple and it worked for centuries.

It is still working!  There is still a barrel at Post Office Bay.  It is no more than a hundred yards or so from the beach.    This system has been in continuous use since it first started over 200 years ago.

"Post Office" at Post Office Bay

Even the post office has an interesting tidbit of history.  British whaling vessels had acted as privateers when Britain had conflicts with other nations and, as such, were considered fair game in time of war.  During the War of 1812, the American frigate USS Essex, under Captain David Porter, was dispatched to the Pacific.  She decimated the British whaling fleet, capturing 12 British whalers and taking 360 prisoners.   As the story goes, Capt. Porter was able to identify what British whaling ships were in the area and their approximate locations by going through the mail left in the post office barrel on Floreana Island. 

The first USS Essex of the United States Navy was a 36-gun or 32-gun sailing frigate that participated in the Quasi-War with France, the First Barbary War, and in the War of 1812. The British captured her in 1814 and she then served as HMS Essex until sold at public auction in 1837. (By Joseph Howard (1789 - 1857) - Originally from de.wikipedia; description page is/was here., Public Domain, https://commons.wikimedia.org/w/index.php?curid=1741968)

 Visiting the Post Office. While we gathered around, the guides dug out the postcards left in the barrel and began to read off addresses.  Quite a few postcards were claimed by our group to be delivered once they returned home.  We did not hear any cities close to us, so we did not take any.  However, we did leave some from us, hopefully to be picked up and delivered by future visitors.

Guides with the postcards

Reading off destination cities on the postcards

There is more.  While people were milling around I went over and acted like I was checking out the inside, which actually I was.  Inside the barrel above the door was a geocache, GC3ND9R.  Found and log signed!

Back out on the beach. Once that was finished, we began to move on to other activities.  Most of the group was going snorkeling off the beach.  We were going to explore a bit and see what there was to see.  With that in mind, we started to walk down the beach.

Frog on the beach at Post Office Bay.  Several of the cinder or tuff cones are visible in the distance.

Another geocache.  However, the first order of business was yet another geocache, Green Sand Beach Earthcache (GC521N2)..  As the name implies, this has to do with the fact that this is a green beach.  

Only four green beaches in the world.  According to this article there are only four green beaches in the world:  Papakolea Beach on Hawaii's big island, Talofofo Beach on Guam, Hornindalsvatnet in Norway, and what they list as Punta Cormorant, which is on Floreana Island a bit further east from Post Office Bay.  Punta Cormorant is part of the afternoon adventures.

One requirement for claiming the cache was to identify what colors are in the sand and the approximate percentage of each.  Below is a picture of sand we scooped up off the beach.

Dry sand from the beach

The first thing to note is that this is dry sand.  Any dark color is the color of the sand, not from being wet.  Below is a blow-up of sand on the beach which I took later that may be wet.  However it really shows the array of different things in the sand..

Close-up of the sand

Rainbow of colors.  All of the rock/dirt/sand on the island came from the magma ejected when the volcano that created this island erupted.  As the magma cooled, crystals were formed. These crystals can be a rainbow of colors depending on which minerals are present.  In this case there appears to be some red from iron, as we saw in great abundance on Rabida Island.  The white is probably silica and the black is probably basalt.  However, of interest here is the green, which is the mineral olivine.  

Question for my snorkeling friends:  Olivine is more dense than the black lava rock.  Wave action on the beach will tend to wash away the less dense lava rock and concentrate the olivine crystals on the beach.  I saw one place that suggested the sand under the water is therefore darker, i.e. more rich in lava rock, than the sand on the beach, which contains more olivine.  Did you observe that?

Olivine crystals.  Olivine is a magnesium iron silicate.  It is the most abundant mineral in the earth's upper mantle.   I don't know much geology, but my understanding is that to form crystals and hence be able to create a green beach, the magma had to be explosively expelled through water.  I don't know what happened here, but it is true that there are on the order of 50 cinder cones (baby volcanoes?) on the island.  There was enough soft material (cinders and/or tuff?) ejected from these that enabled them to grow to hill or mountain size.

Floreana Island is a broad shield volcano whose surface is densely covered with cinder cones. The most conspicuous of these is Cerro de Pajas, seen here from the north with a spatter cone in the right foreground  There are more than 50 cinder cones dotting the island. (Photo by Ed Vicenzi, 2002, Smithsonian Institution.  https://volcano.si.edu/volcano.cfm?vn=353805&vtab=Photos)

Weathering of olivine.  Despite the fact that olivine is the most abundant mineral in the earth's upper mantle, it weathers rapidly above ground.  The olivine which which weathers away on the beach is replenished by material from the cinder/tuff mounds on the island.  The decomposition process involves combination with CO2 and is, in fact, one of nature's ways of removing CO2 from the atmosphere.  Some have suggested that olivine, volcanic ash and similar silicate rocks should be mined, milled, and spread  widely, mainly in the humid tropics where weathering rates are highest.  This would increase the rate of weathering and reduce the amount of CO2 in the atmosphere.  Who knew!?

Oops.  I am geeking out again.

Back to the travel blog.  As we walked down the beach, we saw one or two blue-footed boobies flying over the water.

 

Boobies hunting for breakfast.  It soon became apparent that they were looking for breakfast. They would fly along scanning the water below.  We could not see anything in the water, but they apparently could.

Once they spotted something they would generally turn back and hover in place, aligning on the selected target

Then they would begin a near vertical powered dive.

 

 Once close to the water they pulled back their wings along their body.

They entered the water looking like a  torpedo.  My guidebook says they may be going as fast as 60 mph when they break the water.

After a small splash, there was a longer than expected delay.  Apparently they swoop down under their prey and grab them from below on the way up.

Then they reappeared and flew low above the water, most of the time getting ready for another go around.  I never saw them with a fish, but the guidebook indicated they can swallow fish underwater, at the surface, or in flight.  If this bird caught anything, he always swallowed it under the water.

 Blue-footed boobies are comical birds when they are walking around on land, but they are anything but while diving for food.  There were only a couple of birds, but they were incredible to watch.  We spent quite some time just watching them dive over and over again.

Snorkeling.  By this time, most of the snorkelers were making their way into the water, so we walked back down to watch them.

We were content sitting on the beach watching the action, but the panga arrived to take those of us not snorkeling back to the ship.  Off we went.  That gave us plenty of time to get ready for lunch and one last afternoon of activities.