Print this pageLake Edward in East Africa occupies a classic half graben, bordered by a major fault scarp in the west and a gently sloping hanging wall (basin floor) in the east. The lake is connected to Lake George to the east, via the Kazinga Channel. From Lake George there is today only sluggish flow towards Lake Edward, but it is believed that the Channel functioned as a river channel during low stand periods.
During an IDEAL cruise on Lake Edward in 1996, four cores and several km of shallow seismic data were collected from the lake floor. The seismic data reveals an east facing, northsouth oriented, syn-sedimentary fault ca 15 km off the eastern coast that has a scarp with a minimum of 10 m relief. This fault may be the southern continuation of a large synthetic fault to the major rift fault in the west, observed on satellite images over the area. Sediment on-lap on the uplifted fault block to the west, suggest former lake levels at least 40 m below today’s level.
A core collected from this on-lap area shows a break in sedimentation between ~13,000 and 4,000 14C-yrs BP, perhaps (?) related to a period of intense faulting. This tectonic phase may correlate to volcanic activity in the area. The core also indicates lower lake levels (with exposure?) prior to ~15,000 14C-yrs BP. This correlates well climatic with evidence from nearby Lakes Victoria and Albert, suggesting a dry Late Pleistocene period in East Africa.
AAPG Search and Discovery Article #90925©1999 AAPG Foundation Grants-in-Aid