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Open-File Report O-12-01, Preliminary geologic map of the Mount McLoughlin 7.5-minute quadrangle, Jackson and Klamath Counties, Oregon, by S. A. Mertzman, R. W. Hazlett, S. G. Weaver, I.P. Weaver, J. M. Baum, H. M. Cruz, M. S. Gilmore, T. J. McElfresh, J. L. Nauert, K. E. Nicolaysen, J. T. Rowe, A. Tittler, and W. R. Wright

Order publication CD-ROM, $15, from Nature of the Northwest. CD-ROM contains text report, 1:24,000-scale map plate, Esri and MapInfo GIS files, GIS file metadata, and geochemical sample data.

[Abstract from metadata file] This map is one of a series of geologic maps created for quadrangles in south-central Oregon in the area of the Cascade Mountains just to the west of Klamath Lake in Jackson and Klamath Counties (and and including a small area of northern California at the Oregon and California border).The digital raster graphic (DRG) of the 1988 provisional edition of the U.S. Geological Survey (USGS) 7.5' Mount McLoughlin quadrangle provides the base map on top of which have been placed geospatial vector format layers of the geologic units and unit boundaries/contacts; and point data format layers of the analyzed rock sample collection locations and volcanic centers. The geologic units and their boundaries were determined based on a combination of observations from the field and of hand-sample, thin-section, and geochemical analyses of 85 samples collected from within the Mount McLoughlin USGS 7.5' quadrangle as well as of relevant samples collected from surrounding USGS 7.5' quadrangles.

Although the chemistry data and thin-section observations were used in creating the map, the units are meant to be field-mappable, that is, recognizable by the study of outcrops in the field. The various layers (i.e., geologic units, samples, etc.) of the map were digitized in MapInfo Professional v.7.0 from drawings on paper quadrangles, UTM coordinates, or maps from student research reports. Rock samples were collected and analyzed by X-ray fluorescence (XRF) in 1984, 1991, 1992, 2004, 2006, and 2009. A total of 14 samples from within the Mount McLoughlin 7.5' quadrangle, plus several from surrounding quadrangles (but from units found in the Lake of the Woods North quadrangle), were dated using K-Ar dating methods. The major and trace elemental chemistry data and ages (if dated) of specimens collected within the Lake of the Woods North quadrangle are made available in the samples table of this data set.

preview of Mount McLoughlin geologic map

 

from the text report: