Hazards for bikers in Puerto Villamil include iguanas snoozing in the roads being cleared by policemen, thick mooring lines (old rope) used as speed bumps and sand traps ready to grab your wheels but the biking is pretty quiet. So the loud squeal on my right caused me to swerve sharply until I realized it was a smiling woman on the porch inflating Helium balloons for a Saturday party. Helium has been on my mind. Each of us have an interesting information web to draw on. The sailors on the boat anchored to the north are connected to the sailboats crossing the pacific through a whatsap group. I continue to lean on my network of scientist friends and Helium has come up.

The Park Guides frame the geology but I am always hungry for more. This week I pinged an old friend who is also an expert on Galapagos lavas. Mark specializes in dating ocean rocks. Most of us think of helium as a way to make your voice squeak or for parties. Helium is Mark’s tool to figure out when lavas covered at the land and where in the earth the lava comes from. Heliem is one of those gases that does not like to do much with anyone else. Mark’s favorite helium, Helium3 is either really old (primorial) or came from cosmic rays damaging a rock. In the molten rocks that rush up from deep in the earth, the Helium gets trapped in the itty bitty melt lenses in middle of olivine crystals. Marc crushes olivine crystals in a vacuum inside his sensitive instrument to measure the primordial Helium. The lavas on the island to the west, Fernandina, have higher Helium3 values than any the other Galapagos island. Mark says because there is so much old, primordial Helium 3 the hotspot is right under Fernandina. The hotspot is the sharpie writing on the paper in our model earth the other day. All the Park Guide say the hotspot is under Fernandina because of Mark’s Helium measurements.

Thinking about the other way Heium3 is formed Mark realized he had a clock. The longer the olivine crystals in a lava are at the surface the more they are hit by cosmic rays and the more new Helium3 is made. This process is similar to the longer you are in the sun the more sunburned your exposed skin will get. The Helium3 from the cosmic rays is not released when Mark crushed the olivine crystals as it is stuck in the crystal lattices. So Marc heats up the melts crushed rock and measures the cosmic ray Helium. The Helium clock, how long the lavas have been in the sun, read 4000 years for Fernandina. Fernandina island was formed during the Middle Kingdom of Egypt, after the oldest Pyramids were built and just as the Chinese mastered Bronze working. Still plugging away trying to understand more but so grateful to have such a network of friends. Mark also sent new references on Finch DNA... still digesting those.

We had a quiet day of Saturday pancakes and list making for chores in Santa Cruz. At last we connected with the American sailors anchored next door. We shared lunch, a visit to a tortoise sanctuary and a bike to the edge of town, the solar array and a lava flow. I could not talk anyone into biking to the airport to see the stranded beach deposits with relatively young shells at 3-4 meters above sea level.

Tortoise Reflection: The process of repopulating the tortoises is slow. Darwin said the average ship took 200 tortoises for meat. This went on for decades. The center has released 3000 tortoises or 15 boatloads over 20 years. The process will be slow even if the center continues to hatch more females by incubating the eggs at higher temperatures. Local students adopt and release tortoises but these students are likely to have their own children before the tortoises begin to reproduce at 35 years.