Geology Reference
In-Depth Information
1
Buddha's Dam
A
S A GEOLOGIST
, I've had plenty of surprises in the field, but I never expected that an excur-
sion to a remote corner of Tibet would lead me to a new appreciation for the biblical story of
Noah's Flood. My specialty is geomorphology, the study of processes that create and shape
topography. Over the last several decades I've explored how landscapes evolve—where
stream channels begin, how landslides sculpt hillslopes, and why rivers carve deep gorges
through mountain ranges.
In the spring of 2002 I joined a research expedition to the Tsangpo River in southeastern
Tibet. The team needed a geomorphologist with river experience to study how the Tsangpo
had sawed down through kilometers of rock to carve the world's deepest gorge. I couldn't
turn down the chance to visit the roof of the world.
As we drove down from the pass toward the Tsangpo on the newly paved road southeast
of Lhasa, I noticed flat-topped piles of sediment rising above the valley floor. Known as to-
pographic terraces, these elevated islands of flat ground can form in different ways, most
commonly when an incising river abandons an old riverbed. I watched for clues to determ-
ine what created these.
