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1100318 R0T0 0811 JRW1 23 <br />landslide complex (contemporaneous with deposition of the unit in Early Ordovician time). <br />Because of its age, composition, and location, this ancient landslide did not cause or contribute <br />to the Pikeview Landslide. The Manitou Formation has an exposed thickness of over 200 feet in <br />portions of the Pikeview Quarry, as indicated on the geologic cross sections in Appendix 39. <br />The Manitou Formation is bounded on the east by the Pierre Shale, an Upper Cretaceous age <br />marine unit consisting of yellowish-gray, friable, siltstone, sandstone and shale. It is juxtaposed <br />against the Manitou Formation and other Paleozoic strata in the quarry along the unnamed <br />eastern branch of the Rampart Range Fault Zone (see geologic map and cross sections B-B' <br />through F-F' in Appendix 39). The Pierre Shale is very weak, highly erodible and subject to <br />slope instability. Exposures at the Pikeview Quarry are highly contorted due to tectonic activity <br />associated with the Rampart Range fault. <br />More recent surficial units of Quarternary age are present to the east and north of the main <br />active quarry area. As shown on the geologic map (Appendix 39), these units include alluvium, <br />colluvium, and old landslide deposits. The alluvium is derived from watersheds draining the <br />Rampart Range. The colluvium and old landslide deposits are locally-derived units resulting <br />from weathering of the weak bedrock of the Pierre Formation. <br />Artificial fill, derived from mining and reclamation activities at the quarry, are widely present in <br />the mapped area (Appendix 39). This material varies widely in thickness, from a few feet to 50 <br />feet or more in some areas. Most of the artificial fill on site is derived from reworked Pikes <br />Peak Granite. Unmarketable material derived from the basal Manitou and Sawatch Formations <br />also comprises significant volumes of artificial fill on the quarry property. <br />The approximate limits of the Pikeview Landslide and September 6, 2009 episode of movement <br />are shown on the geologic map (Appendix 39). The approximate limits of the Pikeview <br />Landslide are shown in red on the geologic map. The outlined area includes both the portion of <br />the slope that was displaced, became rubblized, and flowed or slid into Area H, as well as the <br />scarp that formed along the crest of the quarry within the Pikes Peak Granite at the same time. <br />The limits of the September 6, 2009 episode of slope movement are shown in orange on the <br />geologic map. The Pikeview Landslide is shown in profile on cross sections A-A', D-D', E-E',