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Pipe Spring National Monument, in the northernmost part of central
Arizona, is an oasis in an arid landscape. Its springs have
played a part in the history of the American Indians, early
explorers, and Mormon pioneers. The Monument lies within the
boundaries of the Kaibab Indian Reservation.
The
historic fort at Pipe Spring National Monument is known
as "Winsor Castle." |
"Over the past forty years, spring flow from the main spring
(Pipe Spring) gradually diminished, and in the summer
of 1999, the
spring beneath Winsor Castle stopped producing water. Two
other water-producing features on the Monument continued
to flow.... The decline in spring flow has resulted in
a series of hydrological research projects aimed at increased
understanding
of the Pipe Spring groundwater aquifer" (National Park
Service News Release, 3/27/02).
The geologic framework of the region strongly controls groundwater
flow. As part of a National Park Service and USGS partnership,
USGS scientists are mapping the bedrock, surficial, and structural
geology of the Monument and its environs. Four 7.5-minute
(1:24,000)
quadrangles comprise the mapping area: Pipe Valley, Pipe
Spring, Moccasin, and Kaibab quadrangles. They will be mapped
to USGS
standards with emphasis on the local character of the Navajo
Sandstone and Kayenta Formation, their contact, and the
structures
associated with the Sevier fault system. The geologic mapping
and compilation will take three years, beginning in Fiscal
Year 2003.
This task represents one piece of an interdisciplinary USGS
effort to develop a better three-dimensional understanding
of the pathways for groundwater movement to the springs,
and the vulnerability of the springs to groundwater extractions.
The geologic mapping complements proposed high resolution
seismic profiling of features below the surface such as
fracture
zones, jointing, and water tables.
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U.S.
Department of the Interior, U.S.
Geological Survey