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Limited Geological Evaluation <br /> Exploratory Coring, Rose Red Granite Quarry <br /> Lyons,Colorado <br /> SUBSURFACE CONDITIONS AND DISCUSSION <br /> Published maps (e.g., Punongbayan, Cole, Braddock, and Colton 1989)' depict the site <br /> as underlain by the Silver Plume Granite (Ysp). A portion of that geologic map is <br /> reproduced below. Alluvium and Colluvium (Qc) (undivided on the geologic quadrangle <br /> map), the Boulder Creek Granodiorite (Xbc), and Quartzofeldspathic Mica Schist (Xqs) <br /> area also mapped in the project area. The Silver Plume Granite primarily consists of <br /> porphyritic granite with microcline phenocrysts and generally contains microcline, <br /> plagioclase, quartz, biotite, and muscovite. The Boulder Creek Granodirite generally <br /> consists of medium to coarse grained, gray gneissic granodiorite and generally occurs in <br /> small bodies included in the Silver Plume Granite. Quartzofelspathic Mica Schist <br /> generally consists of mica schist and phyllite interbedded with meta-sandstone and its <br /> mineral assemblage varies by metamorphic zone. The alluvium and colluvium mapped <br /> in the project area generally consist of varying fractions of silts, clays, fine to coarse <br /> sands and gravels, cobbles, and boulders. <br /> 55 / <br /> P� i j 1 <br /> oc' <br /> •Ac j Xbc /. <br /> 36 <br /> Approximate Project Area �� Ysp f <br /> Punongbayan, Raymundo, Cole, J.C., Braddock, W.A., and Colton, R.B., 1989, Geologic map of the <br /> Pinewood Lake quadrangle, Boulder and Lanmer Counties, Colorado: U.S. Geological Survey, Geologic <br /> Quadrangle Map GQ-1627, scale 1:24,000 <br /> Job No. 17-3043 GROUND Engineering Consultants, Inc. Page 3 <br />