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Tufa Thoughts — Scenic Limestone Towers
By David Carle, Park Ranger, Mono Lake
Tufa State Reserve
Sure, a picture is worth a thousand words, but the
real thing is always worth a thousand pictures.
The subject is tufa. Pronounced "too-faw."
Not "tuffa" — that's actually a different
kind of mineral. Nor is it "tofu" — that's
a food made from soybean curd.
As a ranger at the Mono Lake Tufa State Reserve, tufa
is my main topic — the primary justification for
the presence of State Park Rangers around the shores
of Mono Lake. So it might seem strange that in the 18
months since I began writing these articles for Mammoth
Times I have never written just about tufa.
The name has come up, of course. There was the article
about the lake's strange water chemistry, where I couldn't
help but mention the chemical reaction between alkaline
lake water and freshwater springs which produce tufa
towers. Another article mentioned the importance of
the rocks to alkali flies when they go underwater to
lay their eggs on them. The flies even help create more
tufa by accumulating calcium carbonate in glands during
their larvae stage and then depositing it on the submerged
towers when they pupate and leave the water as adults.
If I've avoided directly writing on the subject of
the towers themselves, it's because words strain to
do them justice.
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Photographers try to capture
their beauty and mystery. In fact, every summer
sunrise and sunset brings a mini-rush-hour of
photographers to the South Tufa area at Mono Lake.
But nothing can match being there yourself. You
have to see them to believe them.
Plenty of words have been written,
of course. The lake's towers have been called
"cemented cauliflower", "inferior
mortar, dried hard", "the skeletons
of a dying lake", and "petrified springs".
The walk through South Tufa provokes comparisons
to a lunar landscape. People struggle to find
words to capture the experience and the images.
You need to go see for yourself.
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What? You're still sitting there reading this magazine?
Well, despite the difficulty of the task, I'll just
have to try myself. Maybe a couple more paragraphs will
convince you to get up and go.
Think of stalagmites — the columns and spires
which grow up from the floors of caves, below ceiling
drips. Now, subtract the cave.
No, that doesn't quite do the job, does it? Cave formations
and tufa do have a common chemistry — they are
calcium carbonate. But if you ask a geologist to define
"tufa", he should tell you that it is calcium
carbonate formed from the mixing of waters. Two water
sources are necessary.
Mono Lake's alkaline water provides the carbonates
which go into the mix. Think of it as dissolved baking
soda. And underground freshwater, emerging as springs
beneath the lake, provides the calcium source. Mix them
together under the right conditions and, voila! tufa.
Let the reaction continue for awhile, with the spring
flowing constantly up through the heavier, more dense,
saltwater. As it rises through and around the growing
mass, more and more solid material will be deposited.
Ultimately, the towers can grow upward until they reach
the surface of the lake.
Got that? You can now dazzle your friends with these
two fundamental facts: Wherever you find a tufa formation,
1) Mono Lake had to have covered that area at some time,
and 2) a source of freshwater also had to have been
there.
Today we walk among many of the towers stranded on
dry land. That "petrified springs" image evokes
a feeling for the change that has occurred. Few of the
tufas stranded on land have springs still gushing through
or around them. As Mono Lake dropped (a result of the
diversions of streams which are needed to replace evaporation
from the lake), the springs tended to follow the declining
shoreline.
Snorkel or scuba dive among the tufas still underwater
and you will experience something very different. Most
of the underwater towers still appear to have tendrils
of freshwater rising from their peaks. New calcium carbonate
crystals can sometimes be seen forming. The towers are
changing and alive — alive with algae and feasting
fly larvae and adult flies walking around in their silver
bubbles of air.
The interaction between water and tufa shows up even
on land. Visitors to the "groves" don't spend
much of their time amidst the dry, upland formations.
Most of you walk the shoreline itself, where the towers
meet the lake and where the best views can be had of
towers jutting from the water offshore (like emerging
"skeletons"?), doubled in number and scale
by their mirror-image reflections on the lake surface.
It is true that the decline in the lake has actually
allowed us to walk among the tufa towers. It is also
true that experiencing the tufas, without the lake,
is not the same. If you want to see tufa formations
in a dry lake, you can visit "the pinnacles"
in the dry bed of Searles Lake, near Ridgecrest. But
that spot doesn't attract even close to the 200,000
visitors that come to Mono Lake each year.
Mono Lake's tufa towers are only one part of the experience
of a visit here. Tufa formations are the primary focus
of the State Reserve. But they do not stand alone. They
are just part of an unusual mix of scenery, setting
and life at Mono Lake. The total package is what impresses
most; something more than the sum of its individual
parts.
It took me this long to finally write about tufa because
they are not easy to capture in words. But, most of
all, because they are only part of the whole.
Come and see for yourself. Bring your camera. You will
find yourself looking far across the lake, at the vista
of the Sierra Crest to the west and volcanic formations
forming the other three walls of the basin. Soon your
focus will shift. Textures and color and light will
vary and change. A flock of birds will suddenly come
into the picture. And as your attention moves in closer
and closer, you will become aware that the water near
your feet teems with life — brine shrimp and alkali
flies, the unique animals adapted to this unique chemical
soup.
Bent over now, peering into the water, you may suddenly
spot a freshwater spring, not mixing with the salty
lake water, but pushing up through in its quest to float
atop the brine. And there, around the base of the spring,
you may see the yellowish crystals of calcium carbonate
being added to the rocky bottom.
The water of Mono Lake is at the center of it all.
Salty, soapy, and strange. It controls what can —
and cannot — live here. It is at the center of
human controversy over this lake. And it creates the
conditions for tufa towers to form.
There's a joke that says that the name "tufa"
is used here because people used to sell these decorative
towers "tu-fa the price of one". No such sale
could ever be held for Mono Lake as a whole. In its
beauty, setting, and life, Mono Lake is one of a kind.
You need to go see for yourself.
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