DOGAMI Geologic Map Series

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GMS-127, Geologic map of the Dufur area, Wasco County, Oregon, by Jason D. McClaughry, Heather H. Herinckx, Clark A. Niewendorp, Carlie J.M. Azzopardi, and Joshua A. Hackett; 209 p. report; 3 map plates, scale 1:24,000; Esri format geodatabases; shapefiles; metadata; spreadsheets.

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INTRODUCTION [from the report pamphlet]

The Dufur area of Wasco County, Oregon encompasses an area of ~567 km2 (219.1 mi2) in the Middle Columbia Basin, lying across the eastern slopes of the northern Oregon Cascade Range, ~46 km (28.5 mi) east of Mount Hood volcano (Figure 1-1; Plates 1, 2, and 3). The oldest rocks cropping out in the Dufur area are part of the Columbia River Basalt Group (CRBG), the smallest and youngest flood basalt province in the world (Reidel and others, 2013). Younger upper Miocene to lower Pleistocene volcanic rocks unconformably overlie the CRBG in the Dufur area, recording part of the volcano-tectonic development of the northern Oregon Cascade Range over the past 9 m.y. (McClaughry and others, 2020a).

The geology of the Dufur area was mapped by the Oregon Department of Geology and Mineral Industries (DOGAMI) between 2014 and 2020, in collaboration with geoscientists from the Oregon Water Resources Department. Mapping covers the Wolf Run, Dufur West, and Dufur East 7.5' quadrangles, as well as parts of the Friend, Postage Stamp Butte, Sherars Bridge, and Summit Ridge 7.5' quadrangles lying within the watershed boundary of the Middle Columbia Basin. The primary objective of this investigation is to provide an updated and spatially accurate geologic framework for the Dufur area as part of a multi-year study of the geology of the larger Middle Columbia Basin (Figure 1-1, Figure 1-2). Additional key objectives of this project are to: 1) determine the geologic history of volcanic rocks in this part of the northern Oregon Cascade Range; 2) provide significant new details about the structure and fault history of the Yakima Fold Belt and eastern slopes of the northern Oregon Cascade Range; 3) characterize the stratigraphic framework and geologic conditions controlling the distribution of water resources; 4) determine the distribution of potential aggregate sources and other mineral resources; and 5) describe the nature of geologic hazards. New detailed geologic data presented here also provides a basis for future geologic, geohydrologic, and geohazard studies in the Middle Columbia Basin (Figure 1-1).

The core products of this study are this report, accompanying geologic maps and cross sections (Plates 1, 2, and 3), Esri ArcGIS™ geodatabases, and Microsoft Excel® spreadsheets tabulating point data for geochemistry, geochronology, magnetic polarity, orientation points, and well data. The geodatabases present new geologic mapping in a digital format consistent with the USGS National Cooperative Geologic Mapping Program Geologic Map Schema (GeMS) (U.S. Geological Survey National Cooperative Geologic Mapping Program, 2020). They contain spatial information, including geologic polygons, contacts, structures, geochemistry, geochronology, magnetic observation, orientation points, and well data, as well as data about each geologic unit such as age, lithology, mineralogy, and structure. Digitization at scales of 1:8,000 or better was accomplished using a combination of high-resolution lidar topography and imagery. Surficial and bedrock geologic units in the geodatabase are depicted on Plates 1, 2, and 3 at a scale of 1:24,000. The three plates include: 1) a detailed geologic map showing the relationship of both bedrock and surficial units; and 2) a simplified derivative bedrock geologic map used to more readily show the distribution of contrasting bedrock lithologies and critical structural relationships in the map area. Both the geodatabases and geologic maps are supported by this report describing the geology in detail.

Detailed geologic mapping in this part of the Middle Columbia Basin is a high priority of the Oregon Geologic Map Advisory Committee (OGMAC), supported in part by grants from the STATEMAP component of the U.S. Geological Survey (USGS) National Cooperative Geologic Mapping Program under cooperative agreement numbers G15AC00180 and G20AC00202, and by the Oregon Water Resources Department (OWRD) through Interagency Agreements DOGAMI/OWRD IAA #12102013/OWRD 13 057 (2014) and DOGAMI IAA# DASPS-2542-16/OWRD IAA 16 047 (2016). Additional funds were provided by the State of Oregon through the Oregon Department of Geology and Mineral Industries.


Geodatabase is Esri® version 10.7 format.
Metadata is embedded in the geodatabase and in the shapefiles and is also provided as separate .xml formatted files.

MAP PLATES (georeferenced PDFs)

Note: The map plate PDFs are in geospatial PDF format, allowing you to turn on and off layers in the map frame and to find geographic coordinates in the PDF.

Plate 1. Geologic Map of the Wolf Run and Northern Part of the Friend 7.5' Quadrangles, Wasco County, Oregon, scale 1:24,000, 46" x 50"


Plate 2. Geologic Map of the Dufur West and Northern Part of the Postage Stamp Butte 7.5' Quadrangles, Wasco County, Oregon, scale 1:24,000, 44" x 56"

Plate 3. Geologic map of the Dufur East and parts of the Sherars Bridge and Summit Ridge 7.5ʹ Quadrangles, Wasco County, Oregon, scale 1:24,000, 62" x 50"