Geological Map with location of Steamboat Springs (star) and Howelsen Hill- Steamboat Springs (yellow rectangle).  Howelsen Hill is the NE part of Emerald Mountain.  North is up on the map.

Howelsen Hill is a hill on Emerald Mountain (Quarry Mt) near downtown Steamboat Springs. – The oldest continuously operating ski hill, west of the Mississippi.  Howelsen Hill is a well-known for ski jumping and Steamboat’s Winter Carnival Events.

Existing geological data can be compiled and investigated to understand the rock type, topography, slope, and soil types, for example.  Geospatial software like Esri’s ArcMap is very useful for digital analysis and compilation.

 

Map of Howelsen Hill (Google Earth basemap) with 2ft digital contour lines overlain.  Notice the north area in the upper right corner.  The map was oriented from a downtown Steamboat Springs viewpoint as that is how most locals and visitors look to Howelsen Hill.

Topographic contours overlain on Google Earth image of Howelsen Hill – rotated to view as from downtown Steamboat Springs. Contours courtesy of City of Steamboat Springs GIS digital data:  http://steamboatsprings.net/index.aspx?NID=210

 

Using the 2 ft topographic contours, a smooth 3- dimensional surface provides a pleasing visual reference for the Howelsen Hill area. See if you can identify the ski jumps, and alpine slide that are visible in the topographic map.

Howelsen Hill

Howelsen Hill: Smooth 3D surface generated from 2ft contours

 

 

From the topographic surface (using the change in elevation/distance between grid cells), we can construct a slope map.  The slopes on Howelsen Hill range from o to 60 degrees.  Commonly 20-40 degree slopes exist and make it a great ski hill.

Howelsen Hill Slope

Howelsen Hill calculated slope

We can also overlay the geology (as mapped by the USGS – United States Geological Survey) on Howelsen Hill.  For anyone who has hiked the hill, the ridge of sandstone near the top is called the Dakota Sandstone (Kd – dark greenish blue)).  There is extensive geological literature about this formation.  This is also the target of the sandstone quarried from updip or the top of Quarry/Emerald Mountain.  This sandstone unit dips to the west at high angles 65 to 80°degrees.  Otherwise, Howelsen Hill is dominated by Tbp – or Tertiary (age) Browns Park Fm.  This is a variable lithology (type of sediment) unit that is fairly common in Routt County.  Composed of mud, sand, gravel, the Browns Park Fm was deposited as alluvium and mass movements.   Upwelling magma produced uplifts and volcanic eruptions.  Additionally, the Qtr (Quaternary-age, less than 1.8 Million years) is composed of travertine or calcium carbonate deposits.  Think about the thermal and mineral springs around Steamboat.  They are related to the ‘Tertiary’ volcanics and have been around for millions of years.  Not only do they bubble with mineral-rich water, but they can deposit sediment (calcium carbonate/ calcite and sulfate-rich minerals).  The mass of Qtr in the middle of the map was deposited by an ancient mineral spring and has been uplifted since then. The Qal – is Quaternary alluvium (or river deposited material) – Yampa River deposits.  Other important deposits are the Quaternary glacial deposits (which the Old Town is situated on).  Much of the Qal is not actively deposited by the modern Yampa River, but by a glacial Yampa River.  It is composed of unsorted mud to boulder deposits (think about the banks of the Yampa in many places).  Again, Thanks to the USGS Geological Mapping Program that produced this great resource, but also to the USGS for archiving these maps and distributing them online.

Geological Map - Howelsen Hill

Geological Map overlain on Howelsen Hill

 

Not only did the USGS mapping program produce geological maps, but also interpretive cross sections (Snyder, 1980).  The A-A’ cross section is the large-scale E-W cross section across Steamboat Springs to Emerald/Quarry Mountain.  The a-a’ is the snapshot that can be extracted for the Howelsen Hill area.  What is very interesting is the juxtaposition (placing next to each other) of very different types of rocks of very different ages.  The Xgn is Precambrian-age igneous and metamorphic rocks (~1.7 Billion years old – more on this later) – But VERY OLD ROCKS, with a thin covering of Tbp (Tertiary Browns Park).  The Js, Jm, Kd, Kbm… (blue to greenish blue to green) units are Jurassic to Cretaceous (~150 to 100 Million years old).  Yes, old, but not nearly as old as 1.7 Billion.   Uplift during the End of the Cretaceous (~85-65 Million years) and again in the Tertiary (30 to 3 Million years) juxtaposed the VERY OLD ROCKS against the old rocks. The surface/feature that was produced by the forces that lifted up the VERY OLD ROCKS

Howelsen Hill Geological Map and Cross Sections – USGS

 

Another layer of information that can be added includes the USDA (United States Department of Agriculture) soils data.  The USDA provides soils data in the form of georeferenced polygon files.  Interesting observations can be made.  In general, different types of soils are produced or weathered on the rock substrate.  The Kd and Jm (Cretaceous Dakota and Jurassic Morrison) rocks have a couple of soils developed that tend to be sandier whereas the Tbp (Tertiary Browns Park), Kbm (Cretaceous Mancos), Qtr (Quaternary travertine), and Qal (Qaternary alluvium) have different types of soils that tend to be muddy.  The geology/rocks is/are the parent material which form(s) the soils (through weathering processes).  The slope also impacts the soil formation and retention (or lack of soil retention) as well as impacts the correlation between the geology and soils.

Geology (USGS) and Soils (USDA) data for Howelsen Hill as color-draped layer.  Yellow, hollow geological formation polygons with abbreviation (Kd, Jm, Kbm, Qtr, Qal…).  Compare the geological map image (above) with this soil map image.

In summary, Howelsen Hill (the oldest continuous ski area – west of the Mississippi) is part of an uplift (Emerald Mountain) and is composed of ~100 Million year old rocks.  These sedimentary rocks have been tilted upward to relatively high angles (up to 85º) and dip to the west, northwest. Howelsen Hill has relatively high slopes developed on weathered sandstone, mudstone, and carbonate rocks.

 

 

References:

—Snyder, G.L., 1980, Geologic map of the northernmost Gore Range and southernmost Northern Park Range, Grand, Jackson, Routt Counties, Colorado; USGS  Miscellaneous Investigations Series Map I-1114. Map Scale 1:48,000.  http://ngmdb.usgs.gov/Prodesc/proddesc_8974.htm

—Madole, R.F. (1991b). Surficial Geologic Map of the Steamboat Spring 30′ x 60′ quadrangle, Grand, Jackson & Routt counties, Colorado. Us. Geological Survey Miscellaneous Investigation Series Map 1-1825.

—Klein, T.L., Evans, K.V., and DeWitt, E.H., 2010, Geochronology Database for Central Colorado United States Geological Survey (USGS) Data Series 489

—Green, G.N., 1992, The Digital Geologic Map of Colorado in ARC/INFO Format: U.S. Geological Survey Open-File Report 92-0507, 9 p.; http://pubs.usgs.gov/of/1992/ofr-92-0507/ .

—Sloan, Jan, Henry, C.D., Hopkins, M., and Ludington, S., 2003; National Geochronological Database; USGS Report 2003-236 http://pubs.usgs.gov/of/2003/0236/intro.html