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Geologic map of the Alley Spring quadrangle, Shannon County, Missouri

Scientific Investigations Map 3161

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Abstract

The Alley Spring 7.5-minute quadrangle is located in south-central Missouri within the Salem Plateau region of the Ozark Plateaus physiographic province. About 1,990 feet (ft) of flat-lying to gently dipping Lower Paleozoic sedimentary rocks, mostly dolomite, chert, sandstone, and orthoquartzite, overlie Mesoproterozoic volcanic rocks. A small exposure of the volcanic rocks exists near the eastern edge of the quadrangle. Unconsolidated residuum, colluvium, terrace deposits, and alluvium overlie the sedimentary rocks. Karst features, such as sinkholes, caves, and springs, have formed in the carbonate rocks. Many streams are spring fed. Alley Spring, the largest karst spring in the quadrangle, has an average discharge of 81 million gallons per day. The topography is a dissected karst plain with elevation ranging from 630 ft where the Jacks Fork River exits the quadrangle to more than 1,140 ft at numerous places in the northern half of the quadrangle. The most prominent physiographic feature is the valley of the Jacks Fork River. Most of the land in the quadrangle is privately owned and used primarily for grazing cattle and horses and growing timber. A large minority of the land within the quadrangle is publicly owned, either by the Missouri State Forests or by the Ozark National Scenic Riverways of the National Park Service. Geologic mapping for this investigation was conducted in 2003 and 2004.

Geospatial Extents

Additional Publication Details

Publication type:
Report
Publication Subtype:
USGS Numbered Series
Title:
Geologic map of the Alley Spring quadrangle, Shannon County, Missouri
Series title:
Scientific Investigations Map
Series number:
3161
Year Published:
2012
Language:
English
Publisher:
U.S. Geological Survey
Publisher location:
Reston, VA
Contributing office(s):
National Center
Description:
1 Map: 55 inches x 33 inches
Country:
United States
State:
Missouri
Datum:
1927 North American datum
Projection:
Polyconic, Universal Transverse Mercator zone 15
Scale:
24000