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Doc Date:12/11!2001 ~ lI I' ll l ll l ll llll III sss ,~ s/~ : 2.2 CHARACTERIZATION OF SUBSURFACE GEOLOGY 2.2.1 SUMMARY AND CONCLUSIONS The regional geological setting may be characterized as a sequence Creotaceous clastic sedimentary rocks That were deposited in coastal and marine environments. These coal-bearing sedimentary units were folded and faulted during the Laramide Orogeny and are unconformably overlain by the Browns Pork formation and Tertiary basalis 9 To 14 million years in age. At least two systems of faults con be found in the area. These faults have steep dips and where recognizable, normal displacements. Subsequent erosion has produced a rolling terrain that does not closely correspond to the underlying structure although Thick shale sequences generally produce gently rolling topography and hills and ridges are held up by massive sandstones. 2.2.2 RESULTS 2.2.2.1 Geologic Cross Sections Four geologic cross sections (A-A', B-B', C-C', D-D') were constructed for the Moffat area. One cross section (E-E') included here is located on the West Ridge. The location of these cross sections is shown on Exhibit 2.1-I. In addition to drill hole data collected during This project (well logs and analyses are contained in Section 2.2.4), information from holes previously drilled by PB~M as well as from field mapping was used for construction of the cross sections. The cross sections have been drawn with a vertical exaggeration of eight. Cross Section A-A' N,,./ ~~P~ ~~ Cross section A-A' (Exhibit 2.2-I) is the westernmost of two north-south trending cross sections that transect the Moffat Area (Exhibit 2.2-I). The cross section incorporates data from four drill holes (05-01-0002, OS-01-0004, 05-01-0007, OS-01-0009) That intersect the lower coal-bearing member of The Williams Fork Formation. Cross section A-A' shows the lithology and structure from below the Wolfcreek coals to above the Lennox coal. 2.2-I