We began our trip in Cairo. From there we drove to the Dakhla
Oasis and from there into the Sahara Desert.
Our path from Dakhla
is shown in Fig, 1 which shows the rainfall rate for this region
of the Sahara (from Vance 1987). |
 |
Our first stop was in the very dry region at a site called Prince
Kemal el Din Hussein Monument. Fig 2.
This monument is a commemorative
stone that was placed circa 1930 to honor Prince Kemal who
lead many expeditions in the area in the 1920's. We collected
a soil sample on the shoulder of the ridge in the background
about 1 km from the monument. This is probably the driest part
of the Sahara. |
 |
We continued to Jebel Uweinat, a large sandstone formation that
sits on the triple border of Egypt, Lybia, and Sudan. Fig 3
Over several days we hiked extensively around Jebel Uweinat
searching for algae growing under small quartz rocks. In the
Atacama desert the percentage of quartz rocks that are colonized
by algae decreases from about 30% in the wet end to less than
0.1% in the arid core. The presence of these algae is a indicator
of the dryness of the area.
In the Jebel Uweinat area the quartz stones were very sparsely
colonized. In one site on the Sudan side of Uweinat we found
colonization of about 1%.
|
 |
| Jebel Uweinat is a sandstone mountain with many valleys and basins
Fig 4. Rain only falls there about once a decade but the mountain
collects the water and is seeps underground. Trees and plants thrive
just after a rain and those with deep roots can grow on the stored
water. |
 |
 It
had rained a few months before were arrived and the flowers in
the valleys (Wadi) were in bloom. Fig 5. |
The Acacia trees line the valleys and take
water from the subsurface. Fig 6. |
There are springs in the valley of Jebel
Uweinat that have water persistently Fig 7. |
 Apparently
they tap into the water collected
during the infrequent rains. An inscription by the spring dates
to 1934. Fig 8. |
| Although Jebel Uweinat is made
of sandstone we did not find any evidence for endolithic algae
which are known to grown just below the surface of sandstone
in hot and cold deserts. This was a bit puzzling since we expected
that if there was any hypolithic algae then there would also
be endolithic algae if sandstone is present. |
From Jebel Uweinat we continued northeast to another large sandstone
formation, Gilf Kebir. Here again we found sparse hypolithic
algae and no endolithic algae.
At Gilf Kebir we visited the cave of the swimmers.
Fig 9. There are many locations in the area of Jebel Uweinat
and Gilf Kebir that have prehistoric rock art. A common theme
for the rock art is drawings of wild animals such as giraffes.
Some of these show depictions of swimmers. |
 |
When people lived in this area 5000 to 10,000
years ago there was considerably more water. Apparently even
lakes for swimmers.
We discovered some evidence for such lake.
Fig 10. We found reef-like carbonate structures that look very
similar to structures we find on the bottom of carbonate lakes
such as Pavilion Lake in Canada. |
 |
From Gilf Kebir, we drove north toward wetter locations stopping
in the great sand sea. Here we found extensive colonization of
quartz rocks |
|
 |
| Our four trucks fully loaded. We carried all of our fuel and
water and food for 18 days in the desert. We covered a total of
4000 km. |
 |
