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HomeMy WebLinkAboutWEST FOSSIL CREEK PUD, FIRST FILING, PACE WAREHOUSE - PRELIMINARY - 61-88, D - CORRESPONDENCE - GEOTECHNICAL (SOILS) REPORT; „Y Empire Mboratories, Inc. GEOTECHNICAL ENGINEERING & MATERIALS TESTING January 3, 1989 Pace Membership Warehouse 3315 Peoria Street Aurora, Colorado 80010 Attention: Mr. Peter Insana, P.E. Re: Pace Membership Warehouse Fort Collins, Colorado ELI Project No. 7693-2-88 Gentlemen: CORPORATE OFFICE P.O. Box 503 • (303) 484-0359 301 No. Howes • Fort Collins, Colorado 80522 Empire Laboratories, Inc. has reviewed Map 1-855-F of the USGS Miscellaneous Investigations Series "Map Showing Outstanding Natural and Historic Landmarks In The Boulder -Fort Collins -Greeley Area, Front Range Urban Corridor, Colorado" by Brent N. Petrie as well as comments by the City staff regarding the above -mentioned project. The Petrie study states that "Some of the earliest collections of fossil mollusks of the Upper Cretaceous Pierre shale were taken here in the 19th century. Fossils occur chiefly in calcareous concretions in the Larimer Sandstone Member of the Pierre Shale whose outcrop has a south -southwestward trend through the common corner of Sections 1, 2, 11 and 12, which is just south of the U. S. 287 bridge over Fossil Creek." During the site observation performed by an engineering geologist of Empire Laboratories, Inc. as part of the geotechnical investigation for the Pace project, only minor surface outcrops were encountered within the project area. The only area where fossils were encountered on the property was in the bedrock outcrops noted along the crest and the south and east slopes of the knoll in the west -central portion of the site. The fossil encountered is the clam Inoceramus. This fossil is very common and of little value to paleontologists and students. The fossils cannot be removed from the bedrock without destroying them. There are massive bedrock outcrops and large concentrations of fossils in the sandstone member of the Pierre shale south of the project area just north of the Skyview Subdivision. Extensive fossils have been encountered in the sandstone member of the Pierre formation north of Trilby Road in the area of the Good Samaritan Nursing Home. Professor Robert Johnson, a retired engineering geology and paleontology professor from Colorado State University, is of the opinion that the clams and cephalopods found in the Pierre shale are not unique and are not of academic importance. Branch Offices P.O. Box 16859 P.O. Box 1 135 P.O. Box 1744 P.O. Box 5659 Colorado Springs, CO 60935 Longmont, CO 80502 Greeley, CO 80632 Cheyenne, WY 82003 (303) 597-2116 (303) 776-3921 (303) 351-0460 (307) 632-9224 Member of Consulting Engineers Council Pace Membership Warehouse Page 2 January 3, 1989 Mr. Jeff Hynes of the Colorado State Geological Survey also indicated that the fossils found in the Pierre shale are very common. The study by Petrie covered an area that was not site specific for the Pace warehouse site. The Pierre shale outcrops in the project area do not contain extensive exposures of fossils. In our opinion, development of the site would not destroy any rare fossils. The City's comments stated that with regard to geologic hazard the site is rated 4A on a scale of 1 to 7. The geology of the project area along with recommendations for mitigating geologic hazards are included in our "Report of a Geotechnical Investigation" prepared for the site dated November 28, 1988. In our opinion, if the recommendations set forth in our report are followed, geologic hazards at the site will be minimal. If you have any questions regarding our opinion regarding these concerns or if we can be of further service to you on this project, please do not hesitate to contact us. Very truly yours, EMPIRE LABORAT IES, I I C. / A P ei I R , r rod Senior Engineering Geologist cic cc: Vaught Frye Architects - Mr. Frank Vaught RBD, Inc. - Mr. Lloyd McLaughlin