Summary
The Scotts Mills, Silverton, and Stayton NE 7.5 minute quadrangles are situated along the
eastern margin of the Willamette Valley and adjacent lower foothills (Waldo and Silverton Hills) of
the Cascade Range (Fig. 1). The terrain within this area is of low to moderate relief, ranging from
100 to more than 1000 ft above sea level. This area is largely rural, with most of the valley floor
and low-relief foothills under cultivation. In the last decade, the rural areas outside the boundaries
of established towns have experienced significant growth in new homes built and the expansion of
housing subdivisions. This growth has placed an increased demand on existing geologic resources
(e.g., groundwater, sand and gravel, crushed stone) and the need to better understand potential
geologic hazards within this region.
Previous geologic mapping by Piper (1942), Peck and others (1964), Newton (1969),
Hampton (1972), Miller and Orr (1984), Orr and Miller (1984), and Miller and Orr (1986, 1988)
established and refined the general stratigraphic framework of this region. This mapping identified
few faults or folds; earlier investigators were hindered by the lack of reliably identifiable marker
horizons within the stratigraphic section. Werner (1991), using available seismic profile lines and
well data in the Willamette Valley to locate the top of the Columbia River Basalt Group, was able to
identify and map faults within the subsurface. Reconnaissance mapping of the Columbia River
Basalt Group (CRBG) units in this region in the early 1980’s indicated that these stratigraphic units
could serve as a series of unique reference horizons for identifying post-Miocene folding and
faulting (Beeson and others, 1985, 1989; Beeson and Tolan, 1990).
The major emphasis of this investigation was to identify and map CRBG units within the
Scotts Mills, Silverton, and Stayton NE quadrangles and to utilize this detailed CRBG stratigraphy
to identify and characterize structural features.
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Updated December 16, 2005
Data
- Data package TAR.GZ (10 MB)
Digital databases are available for GIS users in ARC/INFO export format format. Those who download digital data should also download the descriptive pamphlet.
Plot Files
The National Geologic Map Database has additional data about this publication
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