Cal Ruleman
Current Research:
Neotectonics of the northern Rio Grande rift between Taos, New Mexico and Leadville, Colorado
Geomorphic evolution and timing of basin integration in the San Luis Valley, Colorado and New Mexico
Rates of bedrock canyon incision along the Rio Grande, New Mexico
Timing late Pleistocene glacial maximum and rates of deglaciation, central Colorado
Biography
Education
1999:B.A., University of Montana, Missoula
2002:M.S., Montana State University, Bozeman
Professional Society Memberships
1996-Present: Geological Society of America
2000-Present: Colorado Scientific Society
Professional Experience
2000-2002: USGS student intern
2002-2004: U.S. Peace Corp Volunteer, Suriname, South America
2004-2007: Geologist, USGS contractor and private sector
2007-Present: Research Geologist, USGS
Science and Products
Denali National Park Geohazards Geologic Mapping
Denali National Park (DENA) is a major draw for tourism and recreation and a major economic engine for central Alaska. However, the geologic forces that created the steep landscape of DENA also make it prone to geologic hazards (geohazards) like landslides, debris flows, and earthquakes. DENA has only one major road, called the ‘Park Road’, that serves nearly all of its infrastructure.
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Plio-Pleistocene Geomorphic Evolution
The Southern Rocky Mountains encompass the highest elevation within the conterminous United Sates, having fifty-three 14,000-ft peaks. Two national parks (Great Sand Dunes and Rocky Mountain), the San Luis Valley National Heritage Area, the Rio Grande Del Norte National Monument, and several wildlife preserves are also in this area. This region has experienced multiple episodes of tectonic...
Geologic map of the Homestake Reservoir 7.5′ quadrangle, Lake, Pitkin, and Eagle Counties, Colorado
The Homestake Reservoir 7.5' quadrangle lies at the northwestern end of the Upper Arkansas Valley, and headwaters of the Arkansas River, and the Roaring Fork, Fryingpan, and Eagle Rivers of the Colorado River system. The quadrangle lies within tectonic provinces of the 1.4 giga-annum (Ga) Picuris orogeny and includes the late Paleozoic...
Ruleman, Chester A.; Michael G. Frothingham; Brandt, Theodore R.; Shaw, Colin A.; Caffee, Marc W.; Goehring, Brent M.; Brugger, Keith A.
Assessing geohazards to the Denali National Park road with geologic mapping
Denali National Park (DENA) is home to iconic and breathtaking landscapes surrounding the tallest mountain range in North America, the Alaska Range. The park, which covers 6 million acres, is a major draw for tourism and recreation, making it an important economic engine for central Alaska. However, the geologic forces that created the beautiful,...
Hudson, Adam M.; Ruleman, Chester A.; Capps, Denny M
Middle Pleistocene formation of the Rio Grande Gorge, San Luis Valley, south-central Colorado and north-central New Mexico, USA: Process, timing, and downstream implications
The Rio Grande is the fourth longest river in North America extending over 3,000 km from the Rocky Mountains to the Gulf of Mexico. The Pleistocene evolution of this river from individual subbasins into a coalesced fluvial system has been long debated. Herein, we constrain the middle Pleistocene evolution of the northernmost and largest Rio Grande...
Ruleman, Chester A.; Hudson, Adam M.; Thompson, Ren A.; Miggins, Daniel P.; Paces, James; Goehring, Brent M.
Geologic map of the Poncha Pass area, Chaffee, Fremont, and Saguache Counties, Colorado
This report presents a 1:24,000-scale geologic map, cross sections, and descriptive and interpretative text for the Poncha Pass area in central Colorado. The map area is irregular in shape, covering all of one 7 ½' quadrangle (Poncha Pass) and parts of five others (Mount Ouray, Maysville, Salida West, Salida East, and Wellsville). The map...
Minor, Scott A.; Caine, Jonathan Saul; Ruleman, Chester A.; Fridrich, Christopher J.; Chan, Christine F.; Brandt, Theodore R.; Holm-Denoma, Christopher S.; Morgan, Leah E.; Cosca, Michael A.; Grauch, V. J. Establishing chronologies for alluvial-fan sequences with analysis of high-resolution topographic data: San Luis Valley, Colorado, USA
On active alluvial fans, debris-flow deposits and frequent avulsions produce a rough topographic surface. As is the case in many initially rough landforms produced by catastrophic processes, the topography of alluvial fans is progressively smoothed, producing textural differences useful in establishing relative age criteria for fans. Here, we...
Johnstone, Samuel A.; Hudson, Adam M.; Nicovich, Sylvia; Ruleman, Chester A.; Sare, Robert M.; Thompson, Ren A.
Geologic map of the Leadville North 7.5’ quadrangle, Eagle and Lake Counties, Colorado
The Leadville North 7.5’ quadrangle lies at the northern end of the Upper Arkansas Valley, where the Continental Divide at Tennessee Pass creates a low drainage divide between the Colorado and Arkansas River watersheds. In the eastern half of the quadrangle, the Paleozoic sedimentary section dips generally 20–30 degrees east. At Tennessee Pass and...
Ruleman, Chester A.; Brandt, Theodore R.; Caffee, Marc W.; Goehring, Brent M. Geophysical expression of buried range-front embayment structure: Great Sand Dunes National Park, Rio Grande rift, Colorado
Great Sand Dunes National Park and Preserve (GRSA, Colorado) lies along the eastern margin of the San Luis Basin and the tectonically active Sangre de Cristo fault system that are part of the northern Rio Grande rift. GRSA lies within a prominent embayment in the range front where two separate sections of the Sangre de Cristo fault system...
Drenth, Benjamin J.; Grauch, V. J.; Ruleman, Chester A.; Schenk, Judith A Geomorphic evolution of the San Luis Basin and Rio Grande in southern Colorado and northern New Mexico
The San Luis Basin encompasses the largest structural and hydrologic basin of the Rio Grande rift. On this field trip, we will examine the timing of transition of the San Luis Basin from hydrologically closed, aggrading subbasins to a continuous fluvial system that eroded the basin, formed the Rio Grande gorge, and ultimately, integrated the Rio...
Ruleman, Chester A.; Machette, Michael; Thompson, Ren A.; Miggins, Dan M; Goehring, Brent M; Paces, James B. Neotectonics and geomorphic evolution of the northwestern arm of the Yellowstone Tectonic Parabola: Controls on intra-cratonic extensional regimes, southwest Montana
The catastrophic Hebgen Lake earthquake of 18 August 1959 (MW 7.3) led many geoscientists to develop new methods to better understand active tectonics in extensional tectonic regimes that address seismic hazards. The Madison Range fault system and adjacent Hebgen Lake–Red Canyon fault system provide an intermountain active tectonic analog for...
Ruleman, Chester A.; Larsen, Mort; Stickney, Michael C. Late Miocene-Pleistocene evolution of a Rio Grande rift subbasin, Sunshine Valley-Costilla Plain, San Luis Basin, New Mexico and Colorado
The Sunshine Valley-Costilla Plain, a structural subbasin of the greater San Luis Basin of the northern Rio Grande rift, is bounded to the north and south by the San Luis Hills and the Red River fault zone, respectively. Surficial mapping, neotectonic investigations, geochronology, and geophysics demonstrate that the structural, volcanic, and...
Ruleman, C.A.; Thompson, R.A.; Shroba, R.R.; Anderson, M.; Drenth, B.J.; Rotzien, J.; Lyon, J.
Geologic map of the Mount Sherman 7.5' quadrangle, Lake and Park Counties, Colorado
The Mount Sherman 7.5- minute quadrangle is located along the crest of the Mosquito Range in between Leadville and Fairplay, Colorado. There are eleven 13,000-foot peaks and one fourteener, Mount Sherman, within the quadrangle. General elevations range from 10,400–14,036 feet (3,200–4,278 meters). The western half of the quadrangle primarily...
Bohannon, Robert G.; Ruleman, Chester A. Identifying buried segments of active faults in the northern Rio Grande Rift using aeromagnetic, LiDAR,and gravity data, south-central Colorado, USA
Combined interpretation of aeromagnetic and LiDAR data builds on the strength of the aeromagnetic method to locate normal faults with significant offset under cover and the strength of LiDAR interpretation to identify the age and sense of motion of faults. Each data set helps resolve ambiguities in interpreting the other. In addition, gravity data...
Grauch, V.J.S.; Ruleman, Chester A.