Geologic Map of the Estes Park 30’ x 60’ Quadrangle, North-Central Colorado By James C. Cole and William A. Braddock Pamphlet to accompany Scientific Investigations Map 3039 U.S. Department of the Interior U.S. Geological Survey CONVERSION FACTORS Multiply By To obtain centimeters (cm) 0.3937 inches (in.) meters (m) 3.281 feet (ft) kilometers (km) 0.6214 miles (mi) To convert Celsius (°C) to Fahrenheit (°F), use formula (°C x 1.8) + 32 Suggested citation: Cole, J.C., and Braddock, W.A., 2009, Geologic map of the Estes Park 30’ x 60’ quadrangle, north-central Colorado: U.S. Geological Survey Scientific Investigations Map 3039, 1 sheet, scale 1:100,000, pamphlet, 56 p. Contents Abstract ...........................................................................................................................................................1 Introduction.....................................................................................................................................................2 Geography and Geomorphology ........................................................................................................3 Compilation Sources and Methods ...................................................................................................5 Acknowledgments ................................................................................................................................5 Description of Map Units ..............................................................................................................................6 Alluvial Units ..........................................................................................................................................6 Glacial Units ...........................................................................................................................................7 Other Surficial Units .............................................................................................................................8 Post-Laramide Sedimentary Rocks ...................................................................................................8 Post-Laramide Intrusive Rocks ..........................................................................................................8 Post-Laramide Volcanic Rocks ...........................................................................................................9 Laramide Sedimentary and Volcanic Rocks .....................................................................................9 Laramide Intrusive Rocks ..................................................................................................................10 Pre-Cenozoic Sedimentary Rocks ...................................................................................................10 Paleozoic(?) Intrusive Rocks .............................................................................................................12 Mesoproterozoic Intrusive Rocks ....................................................................................................13 Mesoproterozoic and (or) Paleoproterozoic Intrusive Rocks .....................................................14 Paleoproterozoic Intrusive Rocks ....................................................................................................14 Paleoproterozoic Metamorphic Rocks ...........................................................................................15 Geologic Setting ...........................................................................................................................................15 Paleoproterozoic Layered Rocks .....................................................................................................16 Paleoproterozoic Intrusive Rocks ....................................................................................................18 Paleoproterozoic Metamorphism ....................................................................................................19 Mesoproterozoic Intrusive Rocks ....................................................................................................22 Kimberlite .............................................................................................................................................23 Pre-Cenozoic Sedimentary Rocks ...................................................................................................25 Laramide Synorogenic Sedimentary Rocks ...................................................................................26 Laramide Intrusive Rocks ..................................................................................................................27 Post-Laramide Sedimentary Rocks .................................................................................................27 Post-Laramide Intrusive and Volcanic Rocks ................................................................................29 Fluvial Gravel .......................................................................................................................................29 Quaternary Deposits ...................................................................................................................................29 Alluvial Deposits..................................................................................................................................29 Diamicton .............................................................................................................................................32 Glacial Deposits ..................................................................................................................................32 Other Surficial Deposits ....................................................................................................................33 Structure........................................................................................................................................................34 Paleoproterozoic Structures ............................................................................................................34 Mesoproterozoic Structures ............................................................................................................35 Longs Peak-St Vrain Batholith .................................................................................................35 Moose Mountain Shear Zone ..................................................................................................36 iv Laramide Orogeny...............................................................................................................................37 Eastern Margin of the Front Range .........................................................................................37 Boulder-Weld Fault Zone ..........................................................................................................38 Western Margin of the Front Range .......................................................................................38 Sandstone Dikes ........................................................................................................................39 Post-Laramide Structures ................................................................................................................39 Braddock Peak Intrusive-Volcanic Complex .........................................................................40 Colorado River Fault Zone ........................................................................................................40 Block-Glide Landslides .............................................................................................................41 Late Miocene-Pliocene Uplift and River Incision ...................................................................................41 Economic Geology .......................................................................................................................................44 Colorado Mineral Belt ........................................................................................................................44 Coal, Oil, and Gas ................................................................................................................................45 Sand and Gravel ..................................................................................................................................46 Quarry Stone ........................................................................................................................................46 Water ..................................................................................................................................................46 Environmental Geology ...............................................................................................................................47 Landslides, Rockfalls, and Debris Flows .........................................................................................47 Expansive Soils....................................................................................................................................48 Floods ..................................................................................................................................................48 References Cited..........................................................................................................................................49