Space data unveils evidence of ancient mega-lake in northern Darfur (Forwarded)

Boston University
Boston, Massachusetts

Contact:
Kira Edler, 617-358-1240

For Release: March 28, 2007

SPACE DATA UNVEILS EVIDENCE OF ANCIENT MEGA-LAKE IN NORTHERN DARFUR

Discovery could lead to detection of new groundwater resources

Boston -- Researchers at the Boston University Center for Remote Sensing
used recently acquired topographic data from satellites to reveal a now dry,
ancient mega-lake in the Darfur province of northwestern Sudan. Drs. Eman
Ghoneim and Farouk El-Baz made the finding while investigating Landsat
images and Radarsat data. Radar waves are able to penetrate the fine-grained
sand cover in the hot and dry eastern Sahara to reveal buried features.

Segments of the lake's shoreline were identified at the constant altitude of
573 +/- 3 meters above sea level. Ghoneim incorporated these segments with
the Shuttle Radar Topography Mission (SRTM) data into a Geographical
Information System to reconstruct the lake and the ancient river courses
that led to it. At its maximum extent, the lake occupied an area of about
30,750 km2 (larger than the area of Massachusetts) and would have contained
approximately 2,530 km3 when full of water in the past.

The researchers made no inferences regarding the age of the lake; however,
its vast extent suggests that it existed for a long period of time when
rainfall was plentiful in the eastern Sahara.

"Field investigations and samples will determine the exact age of the lake,"
said El-Baz, director of the Boston University Center for Remote Sensing.
"One thing is certain -- much of the lake's water would have seeped through
the sandstone substrate to accumulate as groundwater."

"This ancient lake, which represents indisputable evidence of the past rainy
conditions in the eastern Sahara, will have significant consequences for
improving our knowledge of continental climate change and regional
palaeohydrology," said Ghoneim.

According to the researchers, mapping the site of the former lake, named the
Northern Darfur Mega-lake, will help with groundwater exploration efforts in
the Darfur region, where access to fresh water is essential for refugee
survival.

As proven by El-Baz in Egypt, just north of Darfur, former lakes in this
part of the Sahara are underlain by vast amounts of groundwater. His earlier
detection of the "East Uweinat" basin in southwestern Egypt -- where the
groundwater rises to 25 meters below the surface -- resulted in the drilling
of 500 wells to irrigate 100,000 acres of agricultural land.

"Such large sedimentary basins have potential not only in groundwater
resources, but also oil and gas resources at depth," said El-Baz.

A paper detailing the discovery will be published in an upcoming issue of
the International Journal of Remote Sensing.

The Boston University Center for Remote Sensing is a research facility that
was established in 1986. Researchers at the Center apply techniques of
remote sensing and geographic information systems (GIS) to research in the
fields of archaeology, geography and geology. In 1997, the Center was
recognized by NASA as a "Center of Excellence in Remote Sensing."

Founded in 1839, Boston University is an internationally recognized
institution of higher education and research. With more than 30,000
students, it is the fourth largest independent university in the United
States. BU contains 17 colleges and schools along with a number of
multi-disciplinary centers and institutes, which are central to the school's
research and teaching mission.

[NOTE: An image supporting this release is available at
http://www.bu.edu/news/releases/dbte...alake3.JPG.jpg
(68KB)]