Abstract

Mississippian limestones of the Madison, Deseret and Humbug Formations form a band along the south slopes of the Uinta Mountains. Since the uplift of the Uinta Mountain arch in the Late Cretaceous, these limestones have been continually exposed to erosion. One result of erosion was the development of karst aquifers. Dye tracing studies have helped to trace flow paths through several of these karst aquifers.

In strongly glaciated canyons, the lack of measurable water loss from streams crossing the limestone outcrop indicates that karst aquifers have not developed in the 11,000 years since glacial scour. In contrast, well-developed karst aquifers exist in canyons where glacial effects are absent or minimal, such as Pole Creek, Dry Fork and the Brush Creeks. Erosion rates measured in the Dry Fork-Ashley Spring system indicate that 500 cubic yards of calcite are dissolved annually. An “S”-shaped curve showing rates of aquifer enlargement over time may explain the presence of well-developed aquifer systems in some areas and their absence in others.

The zone of active cave development moved down the dip of the limestone as the water table was lowered by canyon cutting and renewed uplift of the mountains. This process could be called monoclinal shifting. Caves marking former underground streams are now exposed in cliffs on canyon sides.

Today, cave systems with high solution rates produce significant amounts of sediment by freeing insoluble material, which is periodically flushed out of the system during periods of high flow, usually during spring snowmelt.