Saudi Aramco World: May/June 2014 - page 19

May/June 2014
17
can often be found on the walls of the sandstone escarp-
ments that surround the lake basin. It can be sampled, the
elevation of deposits noted, and then it can be carbon-dated.
By adding the approximate depth of the lake, and using a
“virtual flooding” computer model, you can, in theory, pro-
ject the extent of the “paleolakes” during each time period.
Kröpelin makes his way around a palm grove near Lake
Edem in Ounianga Serir and up a steep gully of the sand-
stone escarpment that in the Humid Period must have had a
rivulet. He reaches a jutting ledge that offers a view of Edem,
which is completely covered by reeds.
Kröpelin takes notes, and then takes out his geologist’s
hammer to chip out diatomite specimens. “I’m the first ge-
ologist since the origin of Earth to take a sample at this site,”
says Kröpelin. He scrapes away the crust. The sediment does
not resist. He digs his hand into the hole he has dug and
pulls out the diatomaceous earth in white chunks. They’re
fragile. They crunch easily in his hand.
Without carbon dating, it’s hard to be sure of their age,
but he guesses they will prove to be “younger than 6000 to
7000 years old.” Other samples have dated to between 8500
and 9500 years ago. His altimeter reads 405 meters (1300')
above sea level, plus or minus 10 meters.
Less scientifically, but with no less enthusiasm, Fati Dadi,
from the tourism office, brings Kröpelin a handful of sun-
bleached mollusk shells she has chipped from another part
of the ancient lake sediment. “I am making necklaces,” she
explains. “I take a needle and I pierce some holes.
C’est origi-
nale?
” Kröpelin smiles. “Ten thousand years old,” he says.
“You can’t buy that.”
Back near Lake Boukou, we pass a train of camels, and
shortly afterward, our smaller caravan of three Land Cruisers
stops at the water’s edge. We get out and, though the heat of
the day is finally breaking, the lure of a freshwater swim has
one, then another and another of the crew plunging into the
lake. Kröpelin’s last dip here left him with schistosomiasis, the
waterborne, parasitic disease that frequently infects tropical
waters. Yet in true desert-adventurer style, he declares “No risk,
no fun!” and dives in, too. (Four months later, he reports he
has to repeat the treatments.)
A
t Yoan, the largest lake in Ounianga Kebir, huge
drifts of sand blow down to the edge of the deep-
green water. A group of Toubous, men of the local
ethnic group, take shade beneath palm trees that
look as if they had been placed by a landscape
designer. I realize one of the men is Baba. I join him and ask him
where he is more at home, in the desert or in the laboratory?
“Sincerely, I’d rather be in the laboratory. It’s where my joy
is,” says soft-spoken Baba. But then he catches himself. “I think
they are complementary. I love the desert, but I would love the
possibility to submit the results from the desert in the appropri-
ate laboratory where I can participate. But that’s the problem,”
he continues. “Today, in Chad, institutes and universities have
been created, and we have formed a knowledge-based elite, a
core group of researchers, but we have not the laboratories.”
As we speak, a few Chadian members of the expedition’s sup-
port staff fill plastic bottles with the natural salt foam that gath-
ers on the shore of the hyper-saline lake. Kröpelin later explains
that it’s natural salt foam. “You can eat it,” he says, adding that
Chadians regard it as a health tonic.
“With Stefan Kröpelin
[right],
we’re in debt,” says Baba,
left.
“We are
able to understand precisely how these lakes function,” he says.
“Naturally, if we had the means, we’d do [the coring and analysis]
here, and it would be uniquely a Chadian discovery.” In Baba, says
Kröplen, “I have a decade-long friend and trust.”
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