Open-File Report 00-351
Online version 1.0
Print On Demand version
Geologic Map and Database of the Salem East and Turner 7.5-Minute Quadrangles, Marion County, Oregon: A Digital Database
Terry L. Tolan and Marvin H. Beeson
Digital Database By
Christopher B. DuRoss
The Salem East and Turner 7.5-minute quadrangles are situated in the center of the Willamette Valley near the western margin of the Columbia River Basalt Group (CRBG) distribution. The terrain within the area is of low to moderate relief, ranging from about 150 to almost 1,100-ft elevation. Mill Creek flows northward from the Stayton basin (Turner quadrangle) to the northern Willamette Valley (Salem East quadrangle) through a low that dissects the Columbia River basalt that forms the Salem Hills on the west and the Waldo Hills to the east. Approximately eight flows of CRBG form a thickness of up to 700� in these two quadrangles. The Ginkgo intracanyon flow that extends from east to west through the south half of the Turner quadrangle is exposed in the hills along the southeast part of the quadrangle.
Previous geologic mapping by Thayer (1939) and Bela (1981) while providing the general geologic framework did not subdivide the CRBG which limited their ability to delineate structural elements. Reconnaissance mapping of the CRBG units in the Willamette Valley 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). Crenna, et al. (1994) compiled previous mapping in the Willamette Valley in a study of the tectonics of the Salem area.
The major emphasis of this study was to identify and map CRBG units within the Salem East and Turner Quadrangles and to utilize this detailed CRBG stratigraphy to identify and characterize structural features. Water well logs were used to provide better subsurface stratigraphic control. Three other quadrangles (Scotts Mills, Silverton, and Stayton NE) in the Willamette Valley have been mapped in this way (Tolan and Beeson, 1999).
This area was a lowland area of weathered and eroded marine sedimentary when the Columbia River basalts encroached on this area approximately 15-16 m.y. ago. An incipient Coast Range apparently stopped or diverted the fluid lava flows from moving much farther westward toward the coast at this latitude. It is assumed also that an ancestral Willamette River flowed northward through this low-lying area so that water was present as streams and ponds along the flood plain.
Files Available for Download
|Salem East Quadrangle map as a PDF document. Map is 30 x 35 inches. Scale 1:24,000||
|Turner Quadrangle map as a PDF document. Map is 30 x 35 inches. Scale 1:24,000||
|A tarred and gzipped package that contains both maps as Postscript files. Will open into a directory named "00351ps" when unzipped and untarred.||
|The complete database package as a tarred, gzipped file. Will open into a directory named "00351db" when unzipped and untarred.||
|The same data as above but in zip form. Will open into a directory named "00351db" when unzipped.||
|Readme file that describes how to use the digital database as a Microsoft Word document||
|Readme file that describes how to use the digital database as an ASCII text file||
|Readme file that describes how to use the digital database as a PDF document||
|Sometimes clicking on an FTP hyperlink such as those below will display, or attempt to display the file on the screen rather than downloading it. To force a download instead, do the following: Macintosh: hold the mouse button down for a moment to display a pop-up menu and select "Save this link as..." (Netscape Navigator) or "Download Link to Disk" (Internet Explorer) and navigate to where you want the file saved. Windows machines: use the right mouse button to display a pop-up menu and select "Save Link As..." (Netscape Navigator) or "Save Target As..." (Internet Explorer) and navigate to where you want the file saved.|
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Maintained by: Carolyn Donlin
Created: January 3, 2001 (cad)
Last modified: July 28, 2011 (mfd)