Sunday May 12 2018
We did not think we would need to set an alarm
for our 10:30 am meeting time for our guided snorkel trip, but maybe we should
have. We slept and slept and slept in our super cozy camper van.
The neighboring campers were already having an adventure of their own
being stuck in the soft turf of the campground. Not good.
being stuck in the soft turf of the campground. Not good.
In general, I do not love guided tours with a
lot of other tourists. (Personal guide to a specific historic or natural site
is a different matter and highly recommended.) But there is really no other
practical way to experience swimming through the Mid-Atlantic ridge, so we laid
down our $125 per person for this chance.
Geoinfo
The Mid-Atlantic Ridge (MOR) is where the huge
North American tectonic plate and the huger Eurasian tectonic plate are
diverging. For us Americans, this movement creates a convergent plate boundary
with the Pacific plate on the West Coast. It is why we have volcanoes in
Washington, Oregon, and Alaska, and part of the reason we have earthquakes
throughout the West. The MOR is a ridge of volcanic mountains on the
seafloor in the middle of the Atlantic Ocean (clever naming, eh?) except it surfaces
on Iceland. Coupled with a mantle “hot-spot” (more clever naming of a spot on
the Earth where heat from the mantle is closer to the surface, creating
volcanoes and geothermal areas like Hawaii and Yellowstone), Iceland is racked
by volcanic and geothermal activity. Its cold climate means trees and
vegetation do not obscure the amazing geologic exhibit.
We met our Romanian guide and 6 other tourists
at a parking lot within walking distance of the “put-in”. We suited up in
thermal onesies and a dry suit, got explicit instructions to not miss the turn
off for the “take-out”, then put our neoprene hoods and gloves on and were
handed snorkels and masks. We walked about 100 yards to a platform where we
waited, sweating in the 8 degree (50ish Fahrenheit) degree weather in suits
made to withstand 0 degrees (32 Fahrenheit).
 |
| Lucy |
 |
| Drew. It is very hard to push little shutter buttons with big neoprene gloves on. |
The point of all this was to “swim” (float) for 40 minutes down the Silfra fissure.
The Silfra fissure
Entering the water was a shock on the face and
hands, but my body felt surprisingly little cold. Instead, the experience of
floating with the current in super clear water took over. I was simply happy to
look around at the volcanic rocks partially covered with green stringy algae
and white goopy algae, knowing I was floating at the place where two tectonic
plates are spreading at a rate of about 2 cm per year, which is a little less
than an inch and about the rate your fingernails grow.
 |
| Green stringy algae |
The spreading creates a rift zone - essentially a long valley between mountains where new crust can be added to the plates.
 |
| I think this is me pointing to the North American plate on the right and the Eurasian plate on my left. Underwater photography is hard. |
 |
| Pretty narrow section. |
 |
| Imagine these two land masses moving apart from each other at 1 inch per year. It is just so cool. And cold. The water was very cold. |
The current in the crack is created by surface
water and groundwater flowing through the crack to Þingvallavatn (Þ is
pronounced “th” and vatn means lake in Icelandic). This lake is fed by 90%
groundwater and 10% rivers or direct precipitation. The groundwater comes from
recharge on Langjokull ice cap 60 km (40 miles) north of the lake. The travel
time is only 50 or 60 years! That crazy fast recharge rate compared to a lot of
the arid Western US.
We did not miss the left hand turn to get to the take out. At this point we had to actually swim or dog paddle to the take out platform because we were out of the current. Swimming in a giant balloon is kind of hard.
 |
| Looking to the take-out platform. |
I‘m glad Drew was persuaded (by me) to do this
excursion. It was really a once in a lifetime unique experience. Now we
have seen the innards of a rift valley.
