Lost River - Karst Information Portal

2007 NSS Convention Guidebook
Plain, were not glaciated due to their sheltered
positions between the Crawford Upland and
the Knobstone Escarpment. In the Upper East
Fork drainage basin, flow has been diverted
from three or possibly four separate pre-glacial
basins into the current river. This diversion led
to increased flow and rapid entrenchment of
the East Fork White River.
The remaining history of the East Fork
White River is one of alternating alluviation
and entrenchment due to the several advances
and retreats of the Wisconsinan (ending 15,000
years ago) ice sheets. Outwash from the Illinoian
(ending 100,000 years ago) ice sheet entrenched
the East Fork White River approximately 200
feet below the elevation of the Mitchell Plain
surface. Subsequent aggradation has deposited
approximately 60 to 100 feet of alluvial and
colluvial fill in the river valley (Palmer and
90
Palmer, 1975). The lowest elevation of the
river valley is at approximately 400 to 430 feet
above sea level. Palmer and Palmer (1975)
argued that during the intermittent periods of
glaciation, when the river began rapid down
cutting, karst processes predominated and
cavern development was initiated. The periods
between advancing and retreating ice sheets
yielded several periods of relatively short-lived
stable base levels (Palmer and Palmer, 1975).
Aggradation during glacial advance flooded
the majority of the pre-Pleistocene caves in the
area with silt and clay (Powell, 1961).
Three definite periods of static base level
have been recognized by the Palmers in the
Mitchell Plain and/or southern Indiana area:
1. The Lexington-Highland Rim Peneplain
(900 to 1,000 feet above sea level) formed during
Cretaceous time. Represented by accordant
Figure 9. Physiographic and stratigraphic cross-sections from Figure 8 which highlight details of the Mitchell
Plain surfaces and the relationship of lithology to physiology (Palmer and Palmer, 1975)